JP5202019B2 - Angular velocity sensor - Google Patents

Description

  The present invention relates to an angular velocity sensor, and more particularly to a sensor that detects an angular velocity by detecting a Coriolis force acting on a moving vibrator.

  As an angular velocity sensor that is small and suitable for mass production, sensors that detect the angular velocity by causing the vibrator to perform periodic motion (single vibration or rotational motion) and detecting the Coriolis force acting on the vibrator have become widespread. ing. For example, in the following Patent Documents 1 to 3, a structure in which a vibrator is supported on a fixed member in a device housing via a flexible member, and a driving piezoelectric element formed on the surface of the flexible member is provided. By supplying an AC drive signal, the vibrator is maintained in a vibrating state, and the Coriolis force acting on the vibrator in this state is based on the charge generated by the Coriolis force detecting piezoelectric element formed on the surface of the flexible member. An angular velocity sensor that detects an angular velocity by detecting it is disclosed.

  The angular velocity sensor disclosed in each of these documents can be constituted by a piezoelectric element provided on the surface of a flexible member, both of a mechanism for vibrating a vibrator and a mechanism for detecting Coriolis force. Therefore, it can be physically realized by a simple structure in which a necessary number of piezoelectric elements are arranged at predetermined positions of the flexible member, and can be widely used for industrial products that are small and mass-produced. .

Further, Patent Documents 3 and 4 below also disclose examples in which a capacitive element is used as a mechanism for vibrating a vibrator and a mechanism for detecting Coriolis force. Patent Document 5 below discloses a sensor that can detect both angular velocity and acceleration by combining a piezoelectric element and a piezoresistive element.
JP-A-8-35981 JP-A-8-94661 JP-A-8-226931 JP-A-10-227644 Japanese Patent Application No. 2007-023959

  As described above, the operation principle of the conventional general angular velocity sensor is to detect the angular velocity by causing the vibrator in the apparatus casing to perform a periodic motion and measuring the Coriolis force acting on the vibrator. Is. However, since the vibrator is supported in the apparatus housing via the flexible member, vibration energy and circular motion energy of the vibrator are slightly transferred to the apparatus housing via the flexible member. It will be transmitted. If a part of the kinetic energy of the vibrator leaks to the apparatus housing in this way, it is not preferable because it causes a decrease in the measurement accuracy of the angular velocity.

  For example, touching the device housing of the angular velocity sensor during operation will affect the leakage of kinetic energy, and consequently affect the motion of the vibrator. In addition, the angular velocity sensor is usually used by attaching the device housing to a desired detection target.However, if a part of the kinetic energy of the vibrator leaks to the device housing side, The detected value of angular velocity may be different.

  In order to avoid such an adverse effect and enable more accurate angular velocity detection, it is necessary to take measures to avoid leakage of kinetic energy (vibration leakage) from the vibrator to the apparatus housing as much as possible. For this reason, conventionally, measures such as fixing the basic structure of the sensor to the device casing using a flexible adhesive have been taken, but it is difficult to obtain a complete anti-vibration effect. Such vibration leakage has been a factor of reducing the detection accuracy of the angular velocity sensor.

  Therefore, an object of the present invention is to provide an angular velocity sensor that can eliminate vibration leakage from a vibrator to an apparatus housing and improve detection accuracy.

(1) According to a first aspect of the present invention, in the angular velocity sensor,
The main vibrator, the sub vibrator arranged adjacent to the main vibrator, the pedestal arranged adjacent to the sub vibrator, and the flexibility to connect the main vibrator and the sub vibrator. A basic structure having an inner connecting member having a flexible outer connecting member for connecting the sub-vibrator and the pedestal;
An apparatus housing that supports and fixes the pedestal and accommodates the main vibrator and the sub vibrator in a suspended state,
Drive means for driving the main oscillator to perform periodic motion within the apparatus housing;
Detecting means for detecting Coriolis force acting on the main vibrator in a state in which the main vibrator performs a periodic motion, and outputting this as a detected value of angular velocity about a predetermined axis;
Provided,
The main vibrator is constituted by a central weight body, the sub vibrator is constituted by a plurality of M weight bodies arranged in an annular closed region surrounding the side surface of the central weight body, and a pedestal, The inner connection member is configured by M sets of inner bridging portions that connect the center weight body and each of the M weight bodies, and the outer connection member is formed as M. It is constituted by M sets of outer bridge portions that connect each of the weight bodies and the pedestal,
When an XYZ three-dimensional coordinate system having the origin O at the center position of the upper surface of the central weight is defined, and M radiations extending around the origin O are defined on the XY plane of this coordinate system, the basic structure Has an upper surface along the XY plane of this coordinate system, and one weight body constituting each sub-vibrator is arranged on each of the M radiations, and the inner bridging portion and the outer side are arranged along each radiation. Make sure that the bridges are placed one by one,
The inner bridge is connected to the upper end of the “facing surface against the central weight body” of the weight body constituting the sub-vibrator, and outside the upper end of the “facing surface against the pedestal” of the weight body constituting the sub-vibrator. A bridge portion is connected, and a groove portion extending in a direction perpendicular to the radiation in which the weight body is disposed is formed on the upper surface of the weight body constituting the sub vibrator,
The driving means drives the main vibrator to perform a periodic motion in the device casing, and drives the sub-vibrator to move in a direction opposite to the motion of the main vibrator in the device casing. The child and the sub-vibrator are simply oscillated with the same amplitude and the same frequency in the direction parallel to the predetermined common vibration axis, respectively, and the movement direction of the main vibrator and the movement direction of the sub-vibrator are always opposite to each other, and The absolute value of the movement speed of the main oscillator and the absolute value of the movement speed of the sub-vibrator are driven to be equal.

(2) According to a second aspect of the present invention, in the angular velocity sensor,
The main vibrator, the sub vibrator arranged adjacent to the main vibrator, the pedestal arranged adjacent to the sub vibrator, and the flexibility to connect the main vibrator and the sub vibrator. A basic structure having an inner connecting member having a flexible outer connecting member for connecting the sub-vibrator and the pedestal;
An apparatus housing that supports and fixes the pedestal and accommodates the main vibrator and the sub vibrator in a suspended state,
Drive means for driving the main oscillator to perform periodic motion within the apparatus housing;
Detecting means for detecting Coriolis force acting on the main vibrator in a state in which the main vibrator performs a periodic motion, and outputting this as a detected value of angular velocity about a predetermined axis;
Provided,
The main vibrator is constituted by a central weight body, the sub vibrator is constituted by a plurality of M weight bodies arranged in an annular closed region surrounding the side surface of the central weight body, and a pedestal, The inner connection member is configured by M sets of inner bridging portions that connect the center weight body and each of the M weight bodies, and the outer connection member is formed as M. It is constituted by M sets of outer bridge portions that connect each of the weight bodies and the pedestal,
When an XYZ three-dimensional coordinate system having the origin O at the center position of the upper surface of the central weight is defined, and M radiations extending around the origin O are defined on the XY plane of this coordinate system, the basic structure Has an upper surface along the XY plane of this coordinate system, and one weight body constituting each sub-vibrator is arranged on each of the M radiations, and the inner bridging portion and the outer side are arranged along each radiation. Make sure that the bridges are placed one by one,
The inner bridge is connected to the upper end of the “facing surface against the central weight body” of the weight body constituting the sub-vibrator, and outside the upper end of the “facing surface against the pedestal” of the weight body constituting the sub-vibrator. A bridge portion is connected, and a groove portion extending in a direction perpendicular to the radiation in which the weight body is disposed is formed on the upper surface of the weight body constituting the sub vibrator,
The driving means drives the main vibrator to perform a periodic motion in the device casing, and drives the sub-vibrator to move in a direction opposite to the motion of the main vibrator in the device casing. The child and the sub-vibrator are moved in a circular motion in the same period and in the opposite directions on their own motion planes parallel to a predetermined common reference plane, and the motion direction of the main vibrator and the motion direction of the sub-vibrator Is always in the opposite direction, and is driven so that the absolute value of the motion speed of the main vibrator is equal to the absolute value of the motion speed of the sub-vibrator.

(3) According to a third aspect of the present invention, in the angular velocity sensor according to the first or second aspect described above,
A plurality of M weight bodies constituting the sub-vibrator are annularly connected in order to form a single annular weight body.

(4) According to a fourth aspect of the present invention, in the angular velocity sensor according to the first to third aspects described above,
The driving means has a driving piezoelectric element fixed to the surface of the inner connecting member, and a drive control circuit for supplying an AC driving signal to the driving piezoelectric element,
A detecting means for detecting a piezoelectric element fixed on the surface of the inner connecting member; and an angular velocity detecting circuit for detecting a charge generated in the detecting piezoelectric element and outputting a detected value of the angular velocity based on the detection result. It is what you have.

(5) According to a fifth aspect of the present invention, in the angular velocity sensor according to the first to third aspects described above,
The driving means is an AC drive between the driving displacement electrode provided on the surface of the main vibrator, the driving fixed electrode facing the driving displacement electrode and fixed to the apparatus housing, and the pair of driving electrodes. A drive control circuit for supplying a signal,
The detection means includes a detection displacement electrode provided on the surface of the main vibrator, a detection fixed electrode opposed to the detection displacement electrode and fixed to the apparatus housing, and an electrostatic capacitance between the pair of detection electrodes. And an angular velocity detection circuit that detects the capacitance and outputs a detected value of the angular velocity based on the detection result.

(6) According to a sixth aspect of the present invention, in the angular velocity sensor according to the first to third aspects described above,
The driving means is connected to the main driving piezoelectric element fixed to the surface of the inner connecting member, the sub driving piezoelectric element fixed to the surface of the outer connecting member, and the main driving piezoelectric element and the sub driving piezoelectric element. A drive control circuit for supplying a drive signal,
A detecting means for detecting a piezoelectric element fixed on the surface of the inner connecting member; and an angular velocity detecting circuit for detecting a charge generated in the detecting piezoelectric element and outputting a detected value of the angular velocity based on the detection result. It is what you have.

(7) According to a seventh aspect of the present invention, in the angular velocity sensor according to the first to sixth aspects described above,
The mass of the main vibrator and the mass of the sub vibrator are made equal.

  In the angular velocity sensor according to the present invention, a sub vibrator is provided adjacent to the main vibrator, the main vibrator and the sub vibrator are connected by a flexible member, and the sub vibrator and the apparatus housing are connected to each other. Since a structure that connects the fixed pedestal with another member having flexibility is adopted, the kinetic energy transmitted from the main vibrator to the device housing side is absorbed by the movement of the sub vibrator. Will be able to. For this reason, vibration leakage from the main vibrator to the apparatus housing can be eliminated as much as possible, and detection accuracy can be improved. Further, if the sub vibrator is moved in the direction opposite to the main vibrator, the effect of canceling the kinetic energy leaking from the main vibrator and the kinetic energy leaking from the sub vibrator can be obtained. It is possible to more effectively eliminate vibration leakage to the.

  Hereinafter, the present invention will be described based on the illustrated embodiments.

<<< §1. Structure of conventional angular velocity sensor and basic concept of the present invention >>>
First, an example of a basic structure of a conventional angular velocity sensor proposed in the above-mentioned patent documents will be described. FIG. 1 is a top view of a basic structure 100 used in this conventional sensor, and FIG. 2 is a sectional side view of the basic structure 100 shown in FIG. As shown in the figure, the basic structure 100 is a plate-like structure having a square plane, and its upper surface forms a plane. Here, for convenience of explanation, as shown in FIG. 1, an XYZ three-dimensional coordinate system having an origin O at the center position of the upper surface of the basic structure 100 and the upper surface of the basic structure 100 coinciding with the XY plane is defined. . In FIG. 1, the X axis is rightward, the Y axis is upward, and the Z axis is vertically upward with respect to the paper surface. 2 corresponds to a side sectional view of the basic structure 100 shown in FIG. 1 cut along the XZ plane.

  The weight body 110 located at the center of the basic structure 100 is a quadrangular columnar block, and functions as a vibrator as described later. The origin O of the coordinate system is defined at the center position of the upper surface of the weight body 110. On the outer side of the weight body 110, a plate-like bridge portion 120 (X-axis positive region), bridge portion 130 (Y-axis positive region), bridge portion 140 (X-axis negative region), bridge portion 150 (Y-axis negative region) Region) is connected, and a pedestal 160 forming a frame structure is connected to the outside thereof. As shown in the figure, windows W1 to W4 are formed between adjacent bridge portions, and the weight body 110 is connected to the base 160 only by the four bridge portions 120 to 150. It has become.

  As described above, the basic structure 100 forms an integral structure including the weight body 110, the bridging portions 120 to 150, and the base 160. The bottom surface of the pedestal 160 is fixed to the apparatus housing 180. Although only a part of the device housing 180 is shown in FIG. 2, the device housing 180 is a housing that accommodates the entire basic structure 100. That is, the apparatus housing 180 functions to support and fix the pedestal 160 and to accommodate the weight body 110 in a suspended state. The bridging portions 120 to 150 that support the weight body 110 in a suspended state are flexible because they are thin plate-like structures. For this reason, when an external force is applied to the weight body 110, the bridging portions 120 to 150 are bent, and the weight body 110 is displaced with respect to the pedestal 160 (device housing 180).

  In order to configure the angular velocity sensor, in addition to the basic structure 100 shown in the figure, a driving unit that drives the weight body 110 to perform periodic motion (for example, simple vibration) in the apparatus housing 180, and Detection means for detecting Coriolis force acting on the weight body 110 and outputting it as a detected value of angular velocity around a predetermined axis in a state where the weight body 110 is performing periodic motion is required. For example, if the displacement of the weight body 110 in the X-axis direction (Coriolis force acting in the X-axis direction) is detected by the detection means in a state where the weight body 110 is simply vibrated in the Z-axis direction by the driving means, The angular velocity ωy acting around the Y axis can be obtained, and the angular velocity ωx acting around the X axis can be obtained by detecting the displacement of the weight 110 in the Y axis direction (Coriolis force acting in the Y axis direction). Can do. As these driving means and detection means, examples using piezoelectric elements and capacitive elements have been put to practical use, as disclosed in the above-mentioned patent documents.

  As described above, the basic principle of the conventional general angular velocity sensor is to detect the angular velocity by causing the weight body 110 functioning as a vibrator to perform periodic motion and measuring the Coriolis force acting on the weight body 110. Is to do. However, as shown in the figure, the weight body 110 is supported by the apparatus housing 180 via the bridging portions 120 to 150 and the pedestal 160, so that a part of vibration energy of the weight body 110 is part of the apparatus housing 180. It is inevitable that vibration is leaked. As described above, such vibration leakage causes a decrease in angular velocity measurement accuracy. For example, in FIG. 2, when a hand is touched on the apparatus housing 180, the vibration state of the weight body 110 changes, and the detection result of the angular velocity is affected. Specifically, even in a state where “detection value of angular velocity = 0” is supposed to be output as a detection result (a state where angular velocity is not acting), a phenomenon in which some detection value is output occurs. Become.

  Conventionally, in order to reduce the measurement error due to such vibration leakage, for example, measures such as inserting an elastic material between the base 160 and the apparatus housing 180 have been taken. However, it is difficult to obtain a complete vibration isolation effect, and measurement errors due to vibration leakage still occur.

  The present invention proposes a new countermeasure for eliminating such vibration leakage from the vibrator to the apparatus housing and improving detection accuracy. The basic concept is that, apart from the original vibrator (main vibrator) used for angular velocity detection, a sub-vibrator is prepared and the physical path from the main vibrator to the device housing ( This sub-vibrator is arranged in the middle of the vibration transmission path) to serve as a damper. Hereinafter, the present invention will be described based on some embodiments.

<<< §2. Basic structure used in the first embodiment of the present invention >>>
FIG. 3 is a top view showing a basic structure 200 used in the angular velocity sensor according to the first embodiment of the present invention, and FIG. 4 is a side sectional view thereof. The main structure of the basic structure 200 is the same as the structure of the basic structure 100 described in §1. That is, the basic structure 200 is a plate-shaped structure having a square plane, and there are four spaces between the central weight body 210 and the frame-shaped pedestal 260 arranged so as to surround it. The structure connected by the bridge | crosslinking part. However, different weight bodies are provided in the middle part of the four bridging parts, as will be described later.

  Again, for convenience of explanation, an XYZ three-dimensional coordinate system is defined in which the origin O is at the center position of the upper surface of the central weight body 210 and the upper surface of the basic structure 200 coincides with the XY plane. In FIG. 3, the X axis is rightward, the Y axis is upward, and the Z axis is vertically upward with respect to the paper surface. 4 corresponds to a side cross-sectional view of the basic structure 200 shown in FIG. 3 cut along the XZ plane.

  The central weight body 210 is a quadrangular columnar block and functions as a main vibrator used for original angular velocity detection. On the other hand, the weight body provided at the intermediate portion of each bridging portion functions as a sub vibrator for reducing vibration leakage. As shown in the top view of FIG. 3, an X-axis positive weight body 225 is disposed on the positive region of the X-axis, and a Y-axis positive weight body 235 is disposed on the positive region of the Y-axis. The X-axis negative weight body 245 is disposed on the X-axis negative region, and the Y-axis negative weight body 255 is disposed on the Y-axis negative region. The shape of these weight bodies is a substantially prismatic block as shown in the side sectional view of FIG.

  Grooves G1, G2, G3, and G4 are formed on the upper surfaces of the weight bodies 225, 235, 245, and 255, respectively. As for each weight body 225,235,245,255, the bridge | bridging part is connected to the both sides. Here, the side closer to the central weight body 210 is referred to as “inner side”, and the side closer to the pedestal 260 is referred to as “outer side”, and each weight body 225, 235, 245, 255 and the central weight body The bridging portion connecting 210 is called an “inner bridging portion”, and the bridging portion connecting each weight body 225, 235, 245, 255 and the base 260 is called an “outer bridging portion”.

  In the present invention, a member that connects the main vibrator and the sub vibrator is referred to as an “inner connection member”. Therefore, in the case of the first embodiment, the “inner connection member” is constituted by the four inner bridge portions. Specifically, one end is connected to the central weight body 210, the other end is connected to the X-axis positive weight body 225, and the X-axis positive inner bridge portion is disposed along the positive region of the X-axis. 221 and a Y-axis positive-side inner bridging portion 231 that has one end connected to the central weight body 210 and the other end connected to the Y-axis positive weight body 235, and is disposed along the positive region of the Y-axis. One end is connected to the central weight body 210, the other end is connected to the X-axis negative weight body 245, and the X-axis negative-side inner bridging portion 241 is disposed along the negative region of the X-axis. Is connected to the center weight body 210, the other end is connected to the Y-axis negative weight body 255, and the Y-axis negative-side inner bridging portion 251 is disposed along the negative region of the Y-axis. The member is configured.

  Similarly, in the present invention, a member that connects the sub vibrator and the pedestal is referred to as an “outer connection member”. Therefore, in the case of the first embodiment, the “outer connection member” is constituted by the four outer bridge portions. Specifically, one end is connected to the pedestal 260, the other end is connected to the X-axis positive weight body 225, the X-axis positive-side outer bridging portion 222 arranged along the positive region of the X-axis, and one end Is connected to the pedestal 260, the other end is connected to the Y-axis positive weight body 235, the Y-axis positive-side outer bridge portion 232 is disposed along the positive region of the Y-axis, and one end is connected to the pedestal 260. The other end is connected to the X-axis negative weight body 245, the X-axis negative outer bridge 242 is disposed along the negative region of the X-axis, one end is connected to the base 260, and the other end is the Y-axis The outer connection member is configured by the Y-axis negative-side outer bridging portion 252 connected to the negative-side weight body 255 and disposed along the negative region of the Y-axis.

  As shown in FIG. 4, the bottom surface of the base 260 is fixed to the apparatus housing 280. Although only a part of the device housing 280 is illustrated, the device housing 280 is a housing that accommodates the entire basic structure 200. That is, the device housing 280 functions to support and fix the pedestal 260 and accommodate the central weight body 210 in a suspended state. Each of the bridging portions 221, 222, 231, 232, 241, 242, 251, and 252 that support the central weight body 210 in a suspended state is flexible because it is a thin plate-like structure. . For this reason, when an external force is applied to the central weight body 210, the bridge portions are bent, and the weight body 210 is displaced with respect to the pedestal 260 (device housing 280).

  In this way, the weight body 210 functioning as a vibrator is supported in a suspended state from the surrounding four sides by the bridge portion, and the weight body 210 has a certain degree of freedom due to the flexibility of the bridge portion. The basic structure 200 shown in FIGS. 3 and 4 performs the same function as the basic structure 100 shown in FIGS. 1 and 2 in that it can be displaced. However, the main feature of the basic structure 200 is that the central weight body 210 serves as a main vibrator, and a weight body that functions as a sub vibrator in the middle of a connecting member that connects the main vibrator 210 and the base 260. 225, 235, 245, and 255 are provided. Moreover, the inner connection member that connects the main vibrator 210 and the sub-vibrators 225, 235, 245, and 255 and the outer connection member that connects the sub-vibrators 225, 235, 245, and 255 and the pedestal 260 are either Since each of the sub-vibrators 225, 235, 245, and 255 is displaceable with a certain degree of freedom, not only the main vibrator 210 but also each of the sub-vibrators 225, 235, 245, and 255 is constituted by a thin plate-like bridging portion. .

  According to experiments conducted by the present inventor, the basic structure according to the present invention shown in FIGS. 3 and 4 is compared with the case where the weight body 110 is vibrated in the conventional basic structure 100 shown in FIGS. It was confirmed that the vibration energy (vibration leakage) transmitted to the apparatus housings 180 and 280 is significantly reduced when the central weight body 210 is vibrated in the body 200. This is because weight bodies 225, 235, 245, and 255 that function as sub-vibrators are arranged on a path through which vibration energy of the central weight body 210 that functions as the main vibrator is transmitted to the base 260. Therefore, it is considered that vibration energy is absorbed by these sub-vibrators and propagation of vibration energy to the base 260 side is suppressed.

  Thus, the technical concept of providing a sub-vibrator between the main vibrator and the pedestal to suppress the propagation of vibration energy of the main vibrator to the pedestal is the most important concept of the present invention. However, the basic structure 200 shown in FIGS. 3 and 4 includes ancillary features for preventing a decrease in measurement accuracy due to vibration leakage to the apparatus housing.

  The first incidental feature is that the connection positions of the inner connecting member and the outer connecting member configured as flexible plate-shaped bridging portions with respect to the sub-vibrator, and the groove portions formed in each sub-vibrator. It exists. As shown in the side sectional view of FIG. 4, the inner connecting members (bridge portions) 221, 241 are the inner side surfaces of the weight bodies 225, 245 that function as sub-vibrators (opposite the center weight body 210. The outer connecting members 222 and 242 (bridged portions) are connected to the upper ends of the outer side surfaces of the weight bodies 225 and 245 that function as sub-vibrators (surfaces facing the base 260). ing. Moreover, grooves G1 and G3 are formed on the upper surfaces of the weight bodies 225 and 245. As shown by a solid line in FIG. 3, four grooves G1 to G4 are formed on the upper surface (position of the sub vibrator) of the basic structure 200, and the grooves G1 and G3 are orthogonal to the X axis. The grooves G2 and G4 extend in a direction perpendicular to the Y axis.

  Thus, when attention is paid from the viewpoints of “connection position between bridging portion and sub-vibrator” and “configuration of groove portion”, it can be seen that basic structure 200 has the following characteristics. That is, as shown in FIG. 4, when the positive direction of the Z-axis is the upward direction and the negative direction of the Z-axis is the downward direction, the upper end of the “opposite surface of the central weight body 210” of the weight 225 of the X-axis positive side The X-axis positive side inner bridging portion 221 is connected, the X-axis positive-side outer bridging portion 222 is connected to the upper end of the “surface facing the base 260” of the X-axis positive-side weight body 225, and the X-axis positive-side weight body 225 A groove portion G1 extending in a direction orthogonal to the X axis is formed on the upper surface. The Y-axis positive-side inner bridging portion 231 is connected to the upper end of the “opposite surface with respect to the central weight body 210” of the Y-axis positive-side weight body 235, and the “opposite surface with respect to the base 260” of the Y-axis positive-side weight body 235 is connected. ”Is connected to the upper end of the Y-axis positive-side outer bridging portion 232, and a groove portion G2 extending in a direction perpendicular to the Y-axis is formed on the upper surface of the Y-axis positive-side weight body 235 (not shown in FIG. 4). ). In addition, the X-axis negative-side inner bridging portion 241 is connected to the upper end of the “opposite surface with respect to the central weight body 210” of the X-axis negative-side weight body 245, and the “opposite surface with respect to the base 260” of the X-axis negative-side weight body 245 is connected. Is connected to the X-axis negative-side outer bridging portion 242, and a groove portion G <b> 3 extending in a direction perpendicular to the X-axis is formed on the upper surface of the X-axis negative-side weight body 245. Further, the Y-axis negative-side inner bridging portion 251 is connected to the upper end of the “opposite surface with respect to the central weight body 210” of the Y-axis negative-side weight body 255, and the “opposite surface with respect to the base 260” of the Y-axis negative-side weight body 255. ”Is connected to the upper end of the Y-axis negative side outer bridging portion 252, and a groove portion G 4 extending in a direction perpendicular to the Y-axis is formed on the upper surface of the Y-axis negative weight body 255 (not shown in FIG. 4). ).

  According to experiments conducted by the inventors of the present application, adopting such a structure as the support structure of the sub-vibrator is extremely effective for suppressing vibration leakage. The reason is that, when such a structure is adopted, a U-shaped section is formed in the vibration energy transmission path, and this U-shaped section does not effectively prevent propagation of vibration energy. It is thought. For example, in the side cross-sectional view of FIG. 4, the vibration energy of the main vibrator 210 is transmitted to the apparatus housing 280 via a route of the inner bridge portion 221, the sub vibrator 225, the outer bridge portion 222, and the base 260. However, when looking at the vibration energy transmission path in the upper part of the sub-vibrator 225, both the bridging portions 221 and 222 are both connected to the upper end of the side surface of the sub-vibrator 225. Since the groove portion G1 extending in the direction orthogonal to the X axis exists on the upper surface, a U-shaped section is formed. The substantial mass body constituting the sub-vibrator 225 has a structure that hangs down below the U-shaped section. The inventor of the present application considers that such a unique structure functions to effectively prevent propagation of vibration energy.

  A second incidental feature of the basic structure 200 is geometric symmetry. As shown in the top view of FIG. 3, in this basic structure 200, in the X-axis positive weight body 225, the Y-axis positive weight body 235, the X-axis negative weight body 245, and the Y-axis negative weight body 255. Are composed of weight bodies having the same shape and the same mass. Moreover, the arrangement of the four weight bodies 225, 235, 245, and 255 is symmetric with respect to both the XZ plane and the YZ plane. Actually, not only the four weight bodies but also the entire geometric structure of the basic structure 200 is symmetric with respect to both the XZ plane and the YZ plane.

  Such symmetry contributes to suppression of vibration leakage. In particular, each embodiment described in the present specification describes a state in which the main vibrator (the central weight 210) is oscillated in a predetermined axis direction in the XYZ three-dimensional coordinate system or a predetermined axis in the XYZ three-dimensional coordinate system. In order to detect the angular velocity in a state of circular movement in an orthogonal plane, it is possible to make the geometric structure of the basic structure 200 symmetrical with respect to both the XZ plane and the YZ plane. It is effective in suppressing vibration leakage to This is because when a periodic motion such as simple vibration or circular motion is performed on the vibrator, the geometrical symmetry related to the periodic motion system is maintained in the vibrator and its support structure. This is because each component of the vibration energy leaking to the apparatus housing side is canceled out.

  As described above, in the basic structure 200 according to the first embodiment of the present invention shown in FIGS. 3 and 4, the vibration energy of the main vibrator (central weight body 210) propagates to the base 260. In addition to the important feature of providing the sub-vibrator (weight bodies 225, 235, 245, 255) for suppression, a configuration in which a U-shaped section is formed in the transmission path of vibration energy It has a first incidental feature of adopting and a second incidental feature of adopting a form that maintains symmetry with respect to both the XZ plane and the YZ plane. With these features, vibration leakage of the main vibrator to the device housing side can be extremely effectively prevented.

<<< §3. Angular velocity sensor according to the first embodiment of the present invention >>>
In §2, the structure of the basic structure 200 used in the angular velocity sensor according to the first embodiment of the present invention has been described. Actually, the basic structure 200 can be configured by, for example, performing an etching process or a mechanical cutting process on a semiconductor substrate such as silicon.

  In order to configure the angular velocity sensor, in addition to the basic structure 200, a driving unit that drives the central weight body 210 that functions as the main vibrator in the apparatus housing 280, and the central weight body 210 are provided. Detection means for detecting the acting Coriolis force and outputting the detected value as an angular velocity detection value around a predetermined axis is required. Here, an example in which a piezoelectric element is used as the driving unit and the detecting unit and a specific angular velocity sensor is configured will be described.

  FIG. 5 is a top view showing a state in which a piezoelectric element is attached to the basic structure 200 shown in FIG. 3 (hatching indicates a piezoelectric element, not a cross section). On the other hand, FIG. 6 is a side cross-sectional view of the basic structure with a piezoelectric element 200 shown in FIG. 5 cut along an XZ plane. As illustrated, piezoelectric elements X11, X12, X13, and X14 are fixed on the X axis on the upper surface of the basic structure 200, and piezoelectric elements Y11, Y12, Y13, and Y14 are fixed on the Y axis. ing.

  As shown in the figure, all of the eight piezoelectric elements are arranged on the inner connecting members (inner bridging portions 221, 231, 241, 251). This is because it functions as a driving means for driving the vibrator or a detecting means for detecting the displacement (displacement based on the Coriolis force) of the central weight body 210 (main vibrator). In other words, in the case of the embodiment shown here, it is not necessary to positively drive the sub-vibrator and to detect the displacement of the sub-vibrator when performing the angular velocity detection operation. There is no need to dispose a piezoelectric element on the connecting member (outer bridge portions 222, 232, 242, 252).

  As illustrated, the piezoelectric elements X11, Y11, X14, and Y14 are disposed in the vicinity of the outer ends of the inner bridging portions 221, 231, 241, and 251 (the ends far from the central weight body 210), and the piezoelectric elements X12 and Y12. , X13, Y13 are arranged in the vicinity of the inner ends of the inner bridging portions 221, 231, 241, 251 (ends close to the central weight body 210). This is because, when the inner bridge portions 221, 231, 241, and 251 are deflected due to the displacement of the central weight body 210, stress is concentrated on both ends thereof, so that a piezoelectric element is disposed at this position. This is because it is efficient both in driving the central weight body 210 and detecting the displacement of the central weight body 210.

  FIG. 7 is a side sectional view showing the structure of the piezoelectric element disposed on the upper surface of the basic structure 200 and its characteristics. As shown in FIG. 7A, each piezoelectric element is composed of a plate-like piezoelectric element body P, an upper electrode EU bonded to the upper surface thereof, and a lower electrode EL bonded to the lower surface. The lower surface of the lower electrode EL of each piezoelectric element is fixed to the upper surface of the basic structure 200, and mechanical deformation generated in the piezoelectric element is transmitted to the basic structure 200 side, and conversely to the basic structure 200 side. The generated mechanical deformation is transmitted to each piezoelectric element side.

  Piezoelectric elements have the property that mechanical deformation occurs when a voltage is applied, and conversely, electric charges are generated when mechanical deformation is applied. The characteristics such as what kind of polarity voltage causes mechanical deformation, or what kind of polarity electric charge occurs when mechanical deformation is applied to individual piezoelectric elements. It is different for each (determined by the polarization process performed when the piezoelectric element is generated). When electrodes are formed on the upper and lower surfaces of the piezoelectric element as in the example shown in FIG. 7A, the electric charge generated by applying mechanical deformation to the piezoelectric element is proportional to the voltage generated between the upper and lower electrodes. Therefore, in the following description, “generated voltage” is treated as equivalent to “generated charge”.

  7B, when a voltage with the upper electrode EU side being positive and the lower electrode EL side being negative is applied as shown in FIG. 7B, a mechanical deformation extending in the lateral direction occurs. As shown in (c), when a voltage with the upper electrode EU side being negative and the lower electrode EL side being positive is applied, mechanical deformation contracting in the lateral direction occurs. Further, when a mechanical deformation extending in the lateral direction is applied, a voltage is generated such that the upper electrode EU side is positive and a lower electrode EL side is negative. When a mechanical deformation contracting in the lateral direction is applied, the upper electrode EU side is A voltage is generated such that the electrode EL side is positive.

  Of course, in carrying out the present invention, it is not always necessary to use a piezoelectric element having such characteristics, and a piezoelectric element having an arbitrary characteristic can be used. However, here, for convenience of explanation, the following explanation will be given by taking as an example the case of using a piezoelectric element having the characteristics shown in FIGS. 7B and 7C. In addition, here, among the eight piezoelectric elements shown in FIG. 5, four piezoelectric elements X12, Y12, X13, and Y13 arranged on the inside are used as driving piezoelectric elements, and four piezoelectric elements arranged on the outside are used. An example in which the piezoelectric elements X11, Y14, X11, and Y14 are used as detection piezoelectric elements will be described (the driving piezoelectric element and the detection piezoelectric element can be interchanged as appropriate).

  Consider a case where an AC voltage signal φ1 as shown in FIG. 8A is supplied to the driving piezoelectric elements X12, Y12, X13, and Y13. Specifically, the lower electrodes EL of the driving piezoelectric elements X12, Y12, X13, and Y13 are fixed to the ground potential, and the AC voltage signal φ1 shown in FIG. give. This AC voltage signal φ1 is a sinusoidal AC signal having a positive peak voltage Vp and a negative peak voltage −Vp, and the horizontal axis in FIG. The driving piezoelectric elements X12, Y12, X13, and Y13 that are supplied with the AC voltage signal φ1 repeat the states shown in FIGS. 7B and 7C every half cycle. It will perform a telescopic motion.

  Here, in the basic structure 200 shown in FIGS. 5 and 6, when the upper surface portion where the driving piezoelectric elements X12, Y12, X13, and Y13 are arranged is extended, the inner bridge portions 221, 231, 241, and 251 are The center weight body 210 is bent so as to be displaced in the positive Z-axis direction (upward in FIG. 6). Conversely, when the upper surface portion where the driving piezoelectric elements X12, Y12, X13, and Y13 are disposed contracts, the inner bridging portions 221, 231, 241, and 251 move the central weight body 210 in the negative Z-axis direction ( Deflection that causes displacement in the lower part of FIG. 6 occurs. Therefore, when the AC voltage signal φ1 as shown in FIG. 8A is supplied to the driving piezoelectric elements X12, Y12, X13, and Y13, the central weight body 210 is moved in the Z-axis direction (the vertical direction in FIG. 6). ).

  FIG. 8B is a graph showing the displacement of the center of gravity G of the central weight body 210. In this graph, the horizontal axis is a time axis t synchronized with the horizontal axis of FIG. 8A, and the vertical axis indicates the Z coordinate value of the center of gravity G of the central weight body 210. Here, the coordinate value Z0 is the Z coordinate value of the center of gravity G of the central weight body 210 in a stationary state when the AC voltage signal φ1 is not supplied, and corresponds to the center position of the amplitude A.

  The central weight body 210 functioning as the main vibrator vibrates in the vertical direction with an amplitude A, and the cycle thereof coincides with the cycle of the AC voltage signal φ1. However, the phase of displacement of the main vibrator 210 is delayed by a predetermined phase difference d with respect to the phase of the AC voltage signal φ1. This is because a mechanical system or a circuit is required from when a predetermined voltage is applied to the driving piezoelectric elements X12, Y12, X13, and Y13 until the main vibrator 210 is actually displaced due to mechanical deformation of the piezoelectric elements. This is because a slight time delay occurs due to the delay of the system. The phase difference d is a value determined according to parameters such as the structure of the basic structure 200, the dimensions and materials of each part, and the frequency of the AC voltage signal φ1. In general, it is known that d = π / 2 when an oscillator is vibrated at its resonance frequency in a specific vibration system.

  As described above, when the main vibrator 210 is simply vibrated in the Z-axis direction, a part of the vibration energy is transmitted to the pedestal 260 through each bridging portion and leaks to the apparatus housing 280. Become. However, as described in §2, in the basic structure 200, since the sub-vibrators 225, 235, 245, and 255 are provided in the middle of the vibration energy transmission path, vibration energy transmitted to the base 260 is obtained. Is greatly reduced.

  Now, when the angular velocity acts in a state where the main vibrator 210 is vibrated in the Z-axis direction, a Coriolis force acts on the main vibrator 210 according to the acting angular velocity. For example, if the angular velocity ωy about the Y axis is applied, the direction of motion of the main vibrator 210 is the Z axis direction, so the Coriolis force Fx in the X axis direction is applied. When the Coriolis force + Fx in the X-axis positive direction acts, the main vibrator 210 tilts in the X-axis positive direction. When the Coriolis force -Fx in the X-axis negative direction acts, the main vibrator 210. Tilts in the negative direction of the X axis.

  Such an inclination of the main vibrator 210 in the X-axis direction can be detected as generated charges of the detecting piezoelectric elements X11 and X14. That is, based on the Coriolis force + Fx in the X-axis positive direction, when the main vibrator 210 tilts in the X-axis positive direction, the piezoelectric element X11 contracts and the piezoelectric element X14 extends, so that the upper electrode of the piezoelectric element X11 has a negative polarity. A voltage is generated, and a positive voltage is generated at the upper electrode of the piezoelectric element X14. Conversely, when the main vibrator 210 tilts in the negative X-axis direction based on the Coriolis force -Fx in the negative X-axis direction, the piezoelectric element X11 expands and the piezoelectric element X14 contracts, so that the upper electrode of the piezoelectric element X11 A positive voltage is generated, and a negative voltage is generated at the upper electrode of the piezoelectric element X14. Therefore, if the potential difference between the two is taken, the absolute value indicates the magnitude of the applied Coriolis force, and the sign indicates the direction of the applied Coriolis force. The magnitude and direction of the Coriolis force indicate the magnitude and direction of the angular velocity ωy about the Y axis.

  Similarly, if the angular velocity ωx around the X axis is applied, the movement direction of the main vibrator 210 is the Z axis direction, and therefore, the Coriolis force Fy in the Y axis direction is applied. Tilt in the axial direction. Such an inclination of the main vibrator 210 in the Y-axis direction can be detected as generated charges of the Coriolis force detecting piezoelectric elements Y11 and Y14. That is, when the main vibrator 210 tilts in the Y-axis positive direction based on the Coriolis force + Fy in the Y-axis positive direction, the piezoelectric element Y11 contracts and the piezoelectric element Y14 extends, so that the upper electrode of the piezoelectric element Y11 has a negative polarity. A voltage is generated, and a positive voltage is generated at the upper electrode of the piezoelectric element Y14. Conversely, when the main vibrator 210 is tilted in the Y-axis negative direction based on the Coriolis force -Fy in the Y-axis negative direction, the piezoelectric element Y11 expands and the piezoelectric element Y14 contracts. A positive voltage is generated, and a negative voltage is generated at the upper electrode of the piezoelectric element Y14. Therefore, if the potential difference between the two is taken, the absolute value indicates the magnitude of the angular velocity ωx around the X axis, and the sign indicates the direction.

  Thus, in the angular velocity sensor according to the first embodiment shown in FIGS. 5 and 6, the angular velocity ωx around the X axis and the angular velocity ωy around the Y axis are obtained in a state where the main vibrator 210 is vibrated in the Z-axis direction. It becomes possible to detect.

  FIG. 9 is a circuit diagram showing an example of a signal processing circuit used for the angular velocity sensor. The four piezoelectric elements X12, X13, Y12, Y13 shown on the upper left side of the figure are the driving piezoelectric elements shown in FIG. 5, and the lower electrode EL thereof is grounded. The drive control circuit 30 functions to adjust the AC signal supplied from the AC signal source 31 and supply the AC drive signal to the drive piezoelectric elements X12, X13, Y12, and Y13. Specifically, for example, an AC voltage signal φ1 as shown in FIG. 8A is generated and applied to the upper electrodes EU of the driving piezoelectric elements X12, X13, Y12, Y13. As described above, the driving piezoelectric elements X12, X13, Y12, and Y13 are periodically deformed, and the main vibrator 210 generates periodic motion (single vibration in the Z-axis direction).

  On the other hand, the four piezoelectric elements X11, X14, Y11, Y14 shown on the lower left side of FIG. 9 are the detecting piezoelectric elements shown in FIG. 5, and the lower electrode EL thereof is grounded. The difference between the voltage values V (X11) and V (X14) of the upper electrodes of the piezoelectric elements X11 and X14 is obtained as the voltage value Vx by the difference circuit 21. Similarly, the voltage values V (Y11) and V (Y14) of the upper electrodes of the piezoelectric elements Y11 and Y14 are obtained by the difference circuit 22 as the voltage value Vy.

  The angular velocity detection circuit 40 is configured to detect piezoelectric elements X11, X14, Y11, Y11 at a predetermined timing synchronized with the periodic movement in a state where the main vibrator 210 performs a periodic movement (single vibration in the Z-axis direction). A process of measuring the generated charge of Y14 and outputting it as a detected value of angular velocity about a predetermined axis is performed. In the case of the angular velocity sensor according to the first embodiment, the voltage value Vx obtained by the difference circuit 21 becomes a detection value of the Coriolis force Fx acting in the X-axis direction, and thus a detection value indicating the angular velocity ωy around the Y-axis. And the voltage value Vy obtained by the difference circuit 22 becomes a detected value of the Coriolis force Fy acting in the Y-axis direction, and is output as a detected value indicating the angular velocity ωx around the X-axis.

  Note that the timing at which the angular velocity detection circuit 40 outputs the voltage values Vx and Vy as the detected values of the angular velocities ωy and ωx is such that the center of gravity G of the main vibrator 210 is the amplitude center position of the single vibration (the coordinates shown in FIG. 8B). It is preferably set at the moment of passing the position corresponding to the value Z0. If the main vibrator 210 performs simple vibration, the speed of the main vibrator reaches the maximum value at the moment when the center of gravity G passes through the center position of the amplitude, so that the acting Coriolis force also reaches the maximum value. Therefore, if the voltages Vx and Vy captured at this timing are output as detection values indicating the angular velocities ωy and ωx as they are, the most efficient detection is possible.

  One method for causing the angular velocity detection circuit 40 to recognize the timing at which the voltage values Vx and Vy are output as the detected values of the angular velocities ωy and ωx is as follows. This is a method applied to the detection circuit 40. The AC signal from the AC signal source 31 is a signal synchronized with the AC voltage signal φ1 shown in FIG. As shown in FIG. 8B, the waveform indicating the displacement of the main vibrator 210 has a predetermined phase difference d with respect to the AC voltage signal φ1. The phase difference d is determined according to mechanical characteristics and vibration frequency unique to the basic structure 200. Accordingly, if the AC signal from the AC signal source 31 and the phase difference d are given to the angular velocity detection circuit 40, the timing at which the center of gravity G of the main vibrator 210 passes through the amplitude center position (in FIG. The timing of crossing the horizontal line indicating the value Z0).

  Another method for causing the angular velocity detection circuit 40 to recognize the measurement timing is to monitor the voltages Vx and Vy obtained from the difference circuits 21 and 22 and set the timing when the absolute value thereof reaches the maximum value as the measurement timing. . As described above, if the main vibrator 210 performs simple vibration, the speed of the main vibrator reaches the maximum value at the moment when the center of gravity G passes through the amplitude center position, so that the acting Coriolis force also reaches the maximum value, The absolute values of the voltages Vx and Vy are also maximum values. Therefore, the voltages Vx and Vy indicating the maximum values may be output as detection values indicating the angular velocities ωy and ωx as they are. However, when this method is adopted, a mechanism for holding the values of the voltages Vx and Vy in time series is necessary to determine whether or not the maximum value is reached. Furthermore, in order to detect the rotational direction of the angular velocity, it is only necessary to perform synchronous detection using the signal from the AC signal source 31.

<<< §4. Modified example of the first embodiment >>
Here, some modifications of the angular velocity sensor according to the first embodiment described in §3 will be described. Note that the modification described here can be similarly applied to other embodiments described in §5 and later.

<4-1: Variation of piezoelectric element>
In the embodiment described in §3, among the eight piezoelectric elements shown in FIG. 5, four piezoelectric elements X12, X13, Y12, and Y13 arranged on the inside are used as driving piezoelectric elements and arranged on the outside. Although the four piezoelectric elements X11, X14, Y11, and Y14 thus used are used as detection piezoelectric elements, the roles of the piezoelectric elements may be reversed. However, since the displacement direction of the main vibrator 210 when the AC drive signal φ1 shown in FIG. 8A is supplied to each of the driving piezoelectric elements X11, X14, Y11, Y14 is opposite, the displacement of the main vibrator 210 However, it is necessary to take into consideration the points different from the graph shown in FIG. Further, since the polarities of charges generated in the detection piezoelectric elements X12, X13, Y12, and Y13 are also different from those in the case where the piezoelectric elements X11, X14, Y11, and Y14 are used as the detection piezoelectric elements, signals in the angular velocity detection circuit 40 are used. It is necessary to pay attention to the processing.

  Further, in the embodiment described in §3, the piezoelectric element having the electrical characteristics as shown in FIGS. 7B and 7C is used. Applying a voltage with the electrode EU side positive and the lower electrode EL side negative causes a mechanical deformation that shrinks in the lateral direction. Applying a voltage with the upper electrode EU side negative and the lower electrode EL side positive applies a horizontal When a mechanical deformation that extends in the direction is generated and a mechanical deformation that extends in the lateral direction is applied, a voltage is generated such that the upper electrode EU side is negative and the lower electrode EL side is positive. It is also possible to use a piezoelectric element having an electrical characteristic that generates a voltage such that the upper electrode EU side is positive and the lower electrode EL side is negative. In this case, it is necessary to consider the handling of electrical signals in the drive control circuit 30 and the angle detection circuit 40 in consideration of the reverse of the electrical characteristics.

  It is also possible to use a mixture of piezoelectric elements having the electrical characteristics shown in FIGS. 7B and 7C and piezoelectric elements having the opposite electrical characteristics. Of course, in this case, it is necessary to determine the phase of the AC drive signal to be supplied and the handling of the generated voltage in consideration of the electrical characteristics of the individual piezoelectric elements. For example, even when four piezoelectric elements X12, X13, Y12, Y13 arranged on the inner side are used as driving piezoelectric elements, the piezoelectric elements X12, X13 are shown in FIGS. 7 (b) and 7 (c). When piezoelectric elements having such electrical characteristics are used, and piezoelectric elements Y12 and Y13 having piezoelectric characteristics opposite to those shown in FIGS. 7B and 7C are used, piezoelectric elements are used. An AC voltage signal φ1 as shown in FIG. 10 (a) is supplied to the elements X12 and X13, and an AC voltage signal φ2 (φ1 and φ1) as shown in FIG. 10 (b) is supplied to the piezoelectric elements Y12 and Y13. Need to supply an anti-phase signal).

<4-2: Variation of the periodic motion of the main oscillator>
In the embodiment described in §3, an example in which the main vibrator 210 is simply vibrated in the Z-axis direction has been described. However, the periodic motion performed by the main vibrator 210 is caused by such simple vibration in the Z-axis direction. It is not limited.

  For example, FIG. 11 shows that 24 piezoelectric elements are arranged on the upper surface of the basic structure 200 shown in FIG. 3 so that the main vibrator 210 can be simply oscillated in an arbitrary coordinate axis direction. This is an example that can also be performed. In FIG. 11, hatching indicates a piezoelectric element, and does not indicate a cross section.

  Here, for convenience of explanation, an Xa axis and an Xb axis that are parallel to the X axis and arranged at a predetermined interval are defined on both sides of the X axis, and are defined on both sides of the Y axis with respect to the Y axis. Are defined in parallel and at predetermined intervals. The Xa axis and the Xb axis are defined at positions symmetrical with respect to the X axis, and the Ya axis and the Yb axis are defined at positions symmetrical with respect to the Y axis. In the modification shown here, as shown in FIG. 11, piezoelectric elements X11, X12, X13, and X14 are arranged on the X axis, and piezoelectric elements X21, X22, X23, and X24 are arranged on the Xa axis. The piezoelectric elements X31, X32, X33, and X34 are arranged on the Xb axis. Piezoelectric elements Y11, Y12, Y13, Y14 are arranged on the Y axis, piezoelectric elements Y21, Y22, Y23, Y24 are arranged on the Ya axis, and piezoelectric elements Y31, Y24 are arranged on the Yb axis. Y32, Y33, Y34 are arranged.

  These 24 piezoelectric elements are all arranged on the inner connecting members (inner bridging portions 221, 231, 241, 251). This means that each piezoelectric element is connected to the central weight body 210 (main vibrator). ) Or a detecting means for detecting the displacement (displacement based on the Coriolis force) of the central weight body 210 (main vibrator). Each piezoelectric element is disposed in the vicinity of both end portions of the inner bridging portions 221, 231, 241, and 251 because stress concentrates on the portions.

  In this angular velocity sensor, in order to cause the main vibrator 210 to vibrate in the X-axis direction, for example, four piezoelectric elements X21, X22, X23, and X24 arranged on the Xa axis and the Xb axis are arranged. Four piezoelectric elements X31, X32, X33, and X34 may be used as driving piezoelectric elements. Specifically, assuming that the electrical characteristics of these eight piezoelectric elements are all the same, the four piezoelectric elements X21, X23, X31, and X33 have an AC voltage signal φ1 shown in FIG. When the AC voltage signal φ2 shown in FIG. 10B is supplied to the four piezoelectric elements X22, X24, X32, and X34, the main vibrator 210 makes a single vibration in the X-axis direction.

  As described above, when both the piezoelectric element arranged on the Xa axis and the piezoelectric element arranged on the Xb axis are used as driving piezoelectric elements, the generated driving energy is symmetric with respect to the X axis. It is possible to stably perform simple vibration along the line.

  Similarly, in this angular velocity sensor, in order to cause the main vibrator 210 to vibrate simply in the Y-axis direction, for example, four piezoelectric elements Y21, Y22, Y23, and Y24 arranged on the Ya axis and on the Yb axis The four arranged piezoelectric elements Y31, Y32, Y33, and Y34 may be used as driving piezoelectric elements. Specifically, assuming that the electrical characteristics of these eight piezoelectric elements are all the same, the four piezoelectric elements Y21, Y23, Y31, Y33 have AC voltage signal φ1 shown in FIG. When the AC voltage signal φ2 shown in FIG. 10B is supplied to the four piezoelectric elements Y22, Y24, Y32, and Y34, the main vibrator 210 makes a single vibration in the Y-axis direction.

  Also in this case, since both the piezoelectric element arranged on the Ya axis and the piezoelectric element arranged on the Yb axis are used as driving piezoelectric elements, the generated driving energy is symmetric with respect to the Y axis. A single vibration along the Y axis can be stably performed.

  Further, in this angular velocity sensor, in order to cause the main vibrator 210 to vibrate in the Z-axis direction, for example, four piezoelectric elements X21, X22, X23, and X24 arranged on the Xa axis and the Xb axis are arranged. The four piezoelectric elements X31, X32, X33, and X34 may be used as driving piezoelectric elements. Specifically, assuming that the electrical characteristics of these eight piezoelectric elements are all the same, the four piezoelectric elements X21, X24, X31, and X34 have an AC voltage signal φ1 shown in FIG. When the AC voltage signal φ2 shown in FIG. 10B is supplied to the four piezoelectric elements X22, X23, X32, and X33, the main vibrator 210 makes a single vibration in the Z-axis direction.

  Alternatively, the four piezoelectric elements Y21, Y22, Y23, and Y24 arranged on the Ya axis and the four piezoelectric elements Y31, Y32, Y33, and Y34 arranged on the Yb axis are used as driving piezoelectric elements. If the electrical characteristics of these eight piezoelectric elements are all the same, the AC voltage signal φ1 shown in FIG. 10 (a) is supplied to the four piezoelectric elements Y21, Y24, Y31, and Y34. Even when the AC voltage signal φ2 shown in FIG. 10B is supplied to the four piezoelectric elements Y22, Y23, Y32, and Y33, the main vibrator 210 can be oscillated in the Z-axis direction.

  Of course, in order to cause the main vibrator 210 to vibrate in the Z-axis direction, a total of 16 piezoelectric elements arranged on the Xa axis, Xb axis, Ya axis, Yb axis are used as driving piezoelectric elements. The AC voltage signal φ1 or φ2 as described above may be supplied to each driving piezoelectric element. As described above, when all 16 piezoelectric elements arranged on the Xa axis, Xb axis, Ya axis, and Yb axis are used as driving piezoelectric elements, the generated driving energy is symmetric with respect to both the X axis and the Y axis. Therefore, the simple vibration along the Z axis can be stably performed.

  It is also possible to cause the main vibrator 210 to move circularly by synthesizing simple vibrations in directions orthogonal to each other while shifting the phase by π / 2. For example, if the above-described simple vibration along the X axis and simple vibration along the Y axis are combined, a circular motion on a plane along the XY plane becomes possible. Specifically, a total of 16 piezoelectric elements arranged on the Xa axis, Xb axis, Ya axis, and Yb axis are used as driving piezoelectric elements, and four piezoelectric elements X21, X31, X23, and X33 are used. Supplies an AC voltage signal φ1 as shown in FIG. 10 (a), and the four piezoelectric elements Y21, Y31, Y23 and Y33 have the phase of the AC voltage signal φ1 as shown in FIG. A signal delayed by 2 is supplied, and an AC voltage signal φ2 as shown in FIG. 10B is supplied to the four piezoelectric elements X22, X32, X24, and X34, and the four piezoelectric elements Y22, Y34, and Y22 are supplied. , Y34 may be supplied with a signal obtained by delaying the phase of the AC voltage signal φ2 as shown in FIG. 10B by π / 2.

  Although an example using a signal having a sine waveform as an AC voltage signal supplied to the driving piezoelectric element is described here, the AC voltage signal supplied to the driving piezoelectric element is not necessarily a signal having a sine waveform. For example, a rectangular wave signal may be used.

  As described above, in the angular velocity sensor shown in FIG. 11, the example in which the main vibrator 210 is driven in various directions has been described. Subsequently, the Coriolis force acting on the main vibrator 210 in each coordinate axis direction is detected in this angular velocity sensor. An example of the method of performing will be described. As described above, in this angular velocity sensor, a total of 16 piezoelectric elements arranged on the Xa axis, Xb axis, Ya axis, and Yb axis are used as driving piezoelectric elements. Therefore, the remaining eight piezoelectric elements are used for detecting the Coriolis force. That is, the piezoelectric elements X11, X12, X13, and X14 arranged on the X axis and the piezoelectric elements Y11, Y12, Y13, and Y14 arranged on the Y axis are used as detection piezoelectric elements.

  First, the Coriolis force Fx acting in the X-axis direction is obtained from voltages V (X11), V (X12), V (X13), and V (X14) obtained from the four piezoelectric elements X11, X12, X13, and X14. be able to. Specifically, if the electrical characteristics of these four piezoelectric elements are all the same, the Coriolis force Fx is calculated by the calculation of (V (X11) + V (X13)) − (V (X12) + V (X14)). Can be detected.

  Further, the Coriolis force Fy acting in the Y-axis direction is obtained from voltages V (Y11), V (Y12), V (Y13), and V (Y14) obtained from the four piezoelectric elements Y11, Y12, Y13, and Y14. be able to. Specifically, if the electrical characteristics of these four piezoelectric elements are all the same, the Coriolis force Fy is calculated by the calculation of (V (Y11) + V (Y13)) − (V (Y12) + V (Y14)). Can be detected.

  Further, the Coriolis force Fz acting in the Z-axis direction is obtained from voltages V (X11), V (X12), V (X13), and V (X14) obtained from the four piezoelectric elements X11, X12, X13, and X14. be able to. Specifically, if the electrical characteristics of these four piezoelectric elements are all the same, the Coriolis force Fz is calculated by the calculation of (V (X11) + V (X14)) − (V (X12) + V (X13)). Can be detected. Alternatively, the Coriolis force Fz can be obtained from the voltages V (Y11), V (Y12), V (Y13), and V (Y14) obtained from the four piezoelectric elements Y11, Y12, Y13, and Y14. Specifically, if the electrical characteristics of these four piezoelectric elements are all the same, the Coriolis force Fz is calculated by the calculation of (V (Y11) + V (Y14)) − (V (Y12) + V (Y13)). Can be detected.

  Of course, using all the voltages obtained from the eight piezoelectric elements X11, X12, X13, X14, Y11, Y12, Y13, Y14, (V (X11) + V (X14)) − (V (X12) + V ( X13)) + (V (Y11) + V (Y14))-(V (Y12) + V (Y13)) It is also possible to detect the Coriolis force Fz.

<4-3: Angular velocity detection around multiple axes>
The basic principle of angular velocity detection is that when a vibrator having mass m is moving at a predetermined speed V in the first coordinate axis direction, a Coriolis force F acting in the second coordinate axis direction acts on this vibrator. If so, the angular velocity ω acting around the third coordinate axis with respect to the apparatus housing satisfies the expression “F = 2m · V · ω”. Therefore, if this equation is used, the angular velocity sensor according to the present invention can be used as a two-axis angular velocity sensor that detects an angular velocity around two axes, or a three-axis angular velocity sensor that detects an angular velocity around three axes. Is possible.

  For example, in order to operate the angular velocity sensor shown in FIG. 11 as a biaxial angular velocity sensor, the third Coriolis force acting in the second coordinate axis direction and the third force in the state where the main vibrator 210 is simply vibrated in the first coordinate axis direction. What is necessary is just to detect the Coriolis force acting in the direction of the coordinate axis. Specifically, for example, if the Coriolis force Fx in the X-axis direction acting on the main vibrator 210 is detected in a state where the main vibrator 210 is oscillated in the Z-axis direction, the angular velocity ωy around the Y-axis is detected. If the Coriolis force Fy in the Y-axis direction acting on the main vibrator 210 is detected, this can be output as a detected value of the angular velocity ωx around the X-axis.

  On the other hand, in order to operate the angular velocity sensor shown in FIG. 11 as a three-axis angular velocity sensor, Coriolis force acting in each coordinate axis direction is detected in a state where the main vibrator 210 is circularly moved in a plane orthogonal to a predetermined coordinate axis. do it. Specifically, for example, when the main vibrator 210 is circularly moved in a plane orthogonal to the Z axis (in a plane parallel to the XY plane), and the main vibrator 210 is moving at a velocity Vx in the X axis direction. If the Coriolis force Fy acting in the Y-axis direction is detected, the angular velocity ωz around the Z-axis can be detected, and if the Coriolis force Fz acting in the Z-axis direction is detected, the angular velocity ωy around the Y-axis is detected. Can be detected. Alternatively, if the Coriolis force Fx acting in the X-axis direction is detected when the main vibrator 210 is moving in the Y-axis direction with the velocity Vy, the angular velocity ωz around the Z-axis can be detected, and Z If the Coriolis force Fz acting in the axial direction is detected, the angular velocity ωx around the X axis can be detected.

  Such a method of detecting angular velocities about multiple axes is a known method disclosed in the above-mentioned patent documents and the like, and therefore detailed description thereof is omitted here.

<4-4: Variations in the form of piezoelectric elements>
The angular velocity sensor according to the first embodiment described in §3 has the structure shown in the side sectional view of FIG. In FIG. 6, for convenience of illustration, the piezoelectric elements X11 to X14 are shown as simple black bars, but actually, each of these piezoelectric elements is shown in the side sectional view of FIG. 7 (a). As shown, it is constituted by a plate-like piezoelectric element body P, an upper electrode EU, and a lower electrode EL. Therefore, when a part of the side sectional view of FIG. 6 is enlarged, it is as shown in the side sectional view of FIG. That is, the piezoelectric elements X11 and X12 are disposed on the upper surface of the X-axis positive inner bridge portion 221 and the piezoelectric elements X13 and X14 are disposed on the upper surface of the X-axis negative inner bridge portion 241. Each piezoelectric element is a piezoelectric element. It is composed of three layers of a main body part P, an upper electrode EU, and a lower electrode EL. The same applies to the piezoelectric elements Y11 to Y14 arranged on the Y axis.

  Thus, instead of fixing individual piezoelectric elements each having an independent three-layer structure to the upper surface of each bridging portion, as shown in the example shown in FIG. If the lower electrodes EL of Y11 to Y14) are replaced with a single common conductive layer EL ′, the individual wirings for the individual lower electrodes EL become unnecessary, so that the structure can be further simplified. Thus, when the lower electrode EL of each piezoelectric element is replaced with a single common conductive layer EL ′, the lower surface of the piezoelectric element body portion P of each piezoelectric element has a common potential, but the upper electrode EU is an individual electrode. Because it functions, there is no operational problem.

  FIG. 14 further shows an example in which the piezoelectric element body P of each of the piezoelectric elements X11 to X14 (and Y11 to Y14 not shown) is replaced with a single common piezoelectric element body P ′. As described above, even if the piezoelectric element body P of each piezoelectric element is replaced with a single common piezoelectric element body P ′, the upper electrode EU functions as an individual electrode, so that there is no operational problem.

  FIG. 15 is a top view of the basic structure 200 for explaining the modification shown in FIGS. 13 and 14 (hatching is for explaining a region and does not show a cross section). The hatched region in the figure is a region where a single common conductive layer EL ′ and a single common piezoelectric element body P ′ are formed. Originally, it is not necessary to form a single common conductive layer EL ′ and a single common piezoelectric element body P ′ on the upper surface portion of the central weight body 210, but as in the example shown in FIG. If the single common conductive layer EL ′ and the single common piezoelectric element main body P ′ are formed in the hatching region including the upper surface portion of the central weight body 210, all of them are formed by a single layer. It becomes possible to constitute the lower electrode EL of the piezoelectric elements X11 to X14 and Y11 to Y14 and the piezoelectric element body P.

<4-5: Omission of groove>
FIG. 16 is a side sectional view showing a modification of the basic structure 200 according to the first embodiment of the present invention shown in FIG. A basic structure 200 ′ shown in FIG. 16 is obtained by omitting the grooves G1 to G4 of the basic structure 200 shown in FIG. 4, and is arranged on the X axis that functions as a sub vibrator. Grooves G1 to G4 are not formed on the upper surfaces of the weight bodies 225 ′ and 245 ′ (and the weight bodies 235 ′ and 255 ′ arranged on the Y axis not shown in FIG. 16).

  As already described in §2, when the groove parts G1 to G4 are formed, a U-shaped section is formed in the vibration energy transmission path, and this U-shaped section effectively prevents the propagation of vibration energy. Fulfills the function of Therefore, in practice, it is preferable to form the grooves G1 to G4 as in the basic structure 200 shown in FIG. However, even when a structure in which the groove portions G1 to G4 are not formed as in the basic structure 200 ′ shown in FIG. 16, the effect of absorbing vibration energy due to the arrangement of the sub-vibrator can be obtained. Compared with the conventional basic structure 100 shown in FIG. 2, the effect of preventing vibration leakage can be obtained.

<4-6: Variations of drive means and detection means>
In §3, an example in which a piezoelectric element is used as a driving unit that moves the main vibrator and a detecting unit that detects the Coriolis force acting on the main vibrator is described. For example, in the case of the example shown in FIG. 5, four drive piezoelectric elements X12, Y12, X13, Y13 fixed to the surface of the inner connecting member, and drive control for supplying an AC drive signal to these drive piezoelectric elements. The circuit 30 (see FIG. 9) constitutes driving means, and the four detection piezoelectric elements X11, Y11, X14, Y14 fixed to the surface of the inner connecting member and the electric charges generated in these detection piezoelectric elements. The detection means is configured by an angular velocity detection circuit 40 (see FIG. 9) that detects and outputs a detection value of the angular velocity based on the detection result.

  However, the drive means and the detection means are not necessarily configured using a piezoelectric element. For example, FIGS. 19 to 21 of JP-A-8-226931 disclose an example of an angular velocity sensor in which a driving unit and a detection unit are configured using a capacitive element. The present invention is also applicable to such an angular velocity sensor. Specifically, a driving displacement electrode provided on the surface of the main vibrator, a driving fixed electrode facing the driving displacement electrode and fixed to the apparatus housing, and a pair of the driving electrodes The drive means may be constituted by a drive control circuit that supplies an AC drive signal. In this case, the main vibrator is driven by the Coulomb force acting between the driving displacement electrode and the driving fixed electrode. Further, a detection displacement electrode provided on the surface of the main vibrator, a detection fixed electrode facing the detection displacement electrode and fixed to the apparatus housing, and a capacitance between the pair of detection electrodes The detection means may be configured by an angular velocity detection circuit that detects the angular velocity and outputs a detection value of the angular velocity based on the detection result. In this case, the Coriolis force acting on the main vibrator is detected as a change in the interelectrode distance (change in capacitance) between the detection displacement electrode and the detection fixed electrode based on the displacement of the main vibrator. become.

  In addition, it is possible to drive the main vibrator using magnetism, or to detect the Coriolis force (displacement of the main vibrator) acting on the main vibrator using magnetism. As described above, the basic concept of the present invention is to use a basic structure having a specific structure. In realizing an angular velocity sensor using such a basic structure, a driving means and a detection means are used. Any specific element may be used.

<<< §5. Angular velocity sensor according to the second embodiment of the present invention >>>
Subsequently, an angular velocity sensor according to a second embodiment of the present invention will be described. A feature of the basic structure used in the angular velocity sensor described here is that a sub-vibrator is arranged at a position surrounding the main vibrator doubly.

  FIG. 17 is a top view showing a basic structure 300 of the angular velocity sensor according to the second embodiment, and FIG. 18 is a side sectional view. When the basic structure 300 shown in FIGS. 17 and 18 is compared with the basic structure 200 shown in FIGS. 3 and 4, it can be seen that they have very similar structures. The substantial difference between the two is the number of sub-vibrators. In the basic structure 200 according to the first embodiment shown in FIG. 3, four beams extending vertically and horizontally are arranged between the central weight body 210 and the pedestal 260, and in the central portion of each beam, Sub-vibrators 225, 235, 245, and 255 are disposed, respectively. On the other hand, in the basic structure 300 according to the second embodiment shown in FIG. 17, four beams extending vertically and horizontally are arranged between the central weight body 310 and the pedestal 360. However, the sub-vibrators 325/326, 335/336, 345/346, 355/356 that are paired with each beam are arranged in each beam. The difference between the two can be easily grasped by comparing the side sectional view of FIG. 4 with the side sectional view of FIG.

  Here too, for convenience of explanation, an XYZ three-dimensional coordinate system is defined in which the origin O is at the center position of the upper surface of the central weight body 310 and the upper surface of the basic structure 300 coincides with the XY plane. FIG. 18 corresponds to a side sectional view of the basic structure 300 shown in FIG. 17 cut along the XZ plane.

  The central weight body 310 is a quadrangular columnar block, and functions as a main vibrator used for original angular velocity detection. On the other hand, the weight body provided at the intermediate portion of each bridging portion functions as a sub vibrator for reducing vibration leakage. In this embodiment, a total of eight weight bodies are used as sub-vibrators. Here, an inner annular closed region surrounding the side surface of the central weight body 310 and an outer annular closed region surrounding the inner annular closed region are defined, and four weight bodies disposed in the inner annular closed region are defined. 325, 335, 345, and 355 are called “inner weight bodies”, and the four weight bodies 326, 336, 346, and 356 arranged in the outer annular closed region are called “outer weight bodies”. To do.

  Further, the four bridging portions connecting the central weight body 310 and each of the four inner weight bodies 325, 335, 345, 355 are called inner bridging portions 321, 331, 341, 351, and four Of the inner weight bodies 325, 335, 345, 355 and the four outer weight bodies 326, 336, 346, 356 are connected to the intermediate bridge portions 322, 332, 342, respectively. The four bridging portions that connect the four outer weight bodies 326, 336, 346, and 356 and the pedestal 360 are called outer bridging portions 323, 333, 343, and 353.

  For example, in the side sectional view of FIG. 18, the right side portion of the central weight body 310 is connected to the inner bridge portion 321, the inner weight body 325, the intermediate bridge portion 322, the outer weight body 326, and the outer bridge portion 323. Connected to the pedestal 360, the left side portion of the central weight body 310 is connected to the pedestal 360 via the inner bridge portion 341, the inner weight body 345, the intermediate bridge portion 342, the outer weight body 346, and the outer bridge portion 343. Has been.

  As a result, in the basic structure 300 shown in FIG. 17, the X-axis positive inner weight body 325 is disposed on the X-axis positive region in the inner annular closed region, and the Y-axis positive region on the Y-axis positive region. An axis positive inner weight body 335 is disposed, an X axis negative inner weight body 345 is disposed on the negative area of the X axis, and a Y axis negative inner weight body 355 is disposed on the negative area of the Y axis. In the outer annular closed region, the X-axis positive outer weight body 326 is disposed on the X-axis positive region, and the Y-axis positive outer weight body 336 is disposed on the Y-axis positive region. Is arranged, the X-axis negative outer weight body 346 is arranged on the negative area of the X-axis, and the Y-axis negative outer weight body 356 is arranged on the negative area of the Y-axis. . Each of these weight bodies functions as a sub-vibrator, and the shape thereof is a substantially prismatic block as shown in the side sectional view of FIG.

  In the case of this embodiment, in order to connect the inner weight bodies 325, 335, 345, 355 and the central weight body 310, one end is connected to the central weight body 310 and the other end is the X axis positive side. An X-axis positive-side inner bridging portion 321 connected to the inner weight body 325 and disposed along the positive region of the X-axis, one end connected to the central weight body 310, and the other end to the Y-axis positive side A Y-axis positive-side inner bridging portion 331 connected to the inner weight body 335 and disposed along the positive region of the Y-axis, one end connected to the center-weight body 310, and the other end to the X-axis negative side An X-axis negative-side inner bridging portion 341 connected to the inner weight body 345 and disposed along the negative region of the X-axis, one end connected to the central weight body 310, and the other end to the Y-axis negative side Connected to the inner weight body 355 and provided with a Y-axis negative-side inner bridging portion 351 disposed along the negative region of the Y-axis. The four bridge portions is a member constituting the inner connecting member.

  Also, in order to connect the outer weight bodies 326, 336, 346, 356 and the pedestal 360, one end is connected to the pedestal 360, the other end is connected to the X-axis positive outer weight body 326, and the X-axis The X-axis positive outer bridge 323 arranged along the positive region, one end connected to the pedestal 360, the other end connected to the Y-axis positive outer weight body 336, and the Y-axis positive region A Y-axis positive outer bridge portion 333 arranged along one end and one end connected to the pedestal 360, the other end connected to the X-axis negative outer weight body 346, and arranged along the negative region of the X-axis. The Y-axis negative outer bridge 343 and one end connected to the pedestal 360, the other end connected to the Y-axis negative outer weight body 356, and arranged along the negative region of the Y-axis Side outer cross-linking portions 353 are provided, and these four cross-linking portions are members constituting the outer connecting member. It made.

  Further, in order to connect the inner weight bodies 325, 335, 345, 355 and the outer weight bodies 326, 336, 346, 356, one end is connected to the X-axis positive inner weight body 325 and the other end is connected. Connected to the X-axis positive outer weight body 326 and connected to the X-axis positive intermediate bridge 322 arranged along the positive region of the X-axis, and one end connected to the Y-axis positive inner weight body 335, The other end is connected to the Y-axis positive outer weight body 336, the Y-axis positive intermediate bridge portion 332 is disposed along the positive Y-axis region, and the one end is connected to the X-axis negative inner weight body 345. The other end is connected to the X-axis negative outer weight body 346, the X-axis negative intermediate bridge portion 342 is disposed along the negative region of the X-axis, and the one end is the Y-axis negative inner weight Connected to the body 355, the other end is connected to the Y-axis negative outer weight body 356, and the Y-axis negative side is disposed along the negative region of the Y-axis. A bridge portion 352 is provided, these four bridge portions is a member constituting the intermediate connecting member (member for connecting the inner weight body and the outer weight member).

  As shown in FIG. 18, the bottom surface of the pedestal 360 is fixed to the apparatus housing 380. Although only a part of the device housing 380 is illustrated, the device housing 380 is a housing that accommodates the entire basic structure 300. That is, the device housing 380 functions to support and fix the pedestal 360 and accommodate the central weight body 310 in a suspended state. Each bridge portion that supports the central weight body 310 in a suspended state is a plate-like structure having a small thickness, and thus has flexibility. For this reason, when an external force is applied to the central weight body 310, each bridge portion is bent, and the weight body 310 is displaced with respect to the pedestal 360 (device housing 380). Of course, not only the weight body 310 that functions as the main vibrator but also each weight body that functions as the sub-vibrator is in a displaceable state with a certain degree of freedom.

  According to experiments conducted by the inventors of the present application, compared to the case where the weight body 210 is vibrated in the basic structure 200 according to the first embodiment shown in FIGS. 3 and 4, the first structure shown in FIGS. It was confirmed that vibration energy (vibration leakage) transmitted to the apparatus housing side is further reduced when the central weight body 310 is vibrated in the basic structure 300 according to the second embodiment. This is presumably because the effect of absorbing vibration energy by the sub-vibrator becomes more prominent by arranging two sub-vibrators in the vibration energy transmission path.

  Also in the second embodiment, the connection positions of the flexible plate-like bridging portions are the weights 225, 226, 235, 236, 245, 246, 255, 256 that function as sub-vibrators. In addition, grooves G1a, G1b, G2a, G2b, G3a, G3b, G4a, and G4b are formed on the upper surface of each weight body.

  More specifically, in the basic structure 300 shown in FIGS. 17 and 18, regarding the X-axis positive side portion, the “opposite surface with respect to the central weight body 310” of the X-axis positive inner weight body 325. The X-axis positive inner bridge portion 321 is connected to the upper end of the X-axis positive inner bridge portion 321 at the upper end of the “opposite surface of the X-axis positive outer weight body 326” of the X-axis positive inner weight body 325. And the other end of the X-axis positive intermediate bridge 322 is connected to the upper end of the “opposite surface to the X-axis positive inner weight body 325” of the X-axis positive outer weight body 326, and the X-axis An X-axis positive-side outer bridging portion 323 is connected to the upper end of the “opposite surface to the pedestal 360” of the positive-side outer weight body 326, and the upper surface of the X-axis positive-side inner weight body 325 and the X-axis positive-side outer weight body. Grooves G1a and G1b extending in a direction perpendicular to the X axis are formed on the upper surface of 326, respectively. There.

  As for the Y-axis positive side portion, the Y-axis positive side inner bridging portion 331 is connected to the upper end of the “opposite surface with respect to the central weight body 310” of the Y-axis positive side inner weight body 335, and the Y-axis positive side. One end of the Y-axis positive-side intermediate bridge 332 is connected to the upper end of the “opposite surface to the Y-axis positive outer weight 336” of the inner weight body 335, and the “Y-axis of the Y-axis positive outer weight body 336” The other end of the Y-axis positive intermediate bridge portion 332 is connected to the upper end of the “opposite surface to the positive inner weight body 335”, and the upper end of the “opposite surface to the pedestal 360” of the Y-axis positive outer weight body 336 is Y. The axial positive outer bridge 333 is connected, and grooves G2a and G2b extending in the direction perpendicular to the Y axis are formed on the upper surface of the Y-axis positive inner weight body 335 and the upper surface of the Y-axis positive outer weight body 336, respectively. Is formed.

  With respect to the X-axis negative side portion, the X-axis negative inner bridging portion 341 is connected to the upper end of the “opposite surface to the central weight body 310” of the X-axis negative inner weight body 345, and the X-axis negative side One end of the X-axis negative intermediate bridge 342 is connected to the upper end of the “opposite surface to the X-axis negative outer weight 346” of the inner weight body 345, and the “X-axis of the X-axis negative outer weight body 346 is connected. The other end of the X-axis negative intermediate bridge 342 is connected to the upper end of the “opposite surface to the negative inner weight body 345”, and the upper end of the “opposite surface to the pedestal 360” of the X-axis negative outer weight body 346 is X The shaft negative outer bridge 343 is connected, and grooves G3a and G3b extending in a direction perpendicular to the X axis are formed on the upper surface of the X axis negative inner weight body 345 and the upper surface of the X axis negative outer weight body 346, respectively. Is formed.

  Further, with respect to the Y-axis negative side portion, the Y-axis negative side inner bridging portion 351 is connected to the upper end of the “opposite surface with respect to the center part weight body 310” of the Y-axis negative side inner weight body 355, One end of the Y-axis negative-side intermediate bridge 352 is connected to the upper end of the “opposite surface to the Y-axis negative-side outer weight body 356” of the inner weight body 355, and the “Y-axis of the Y-axis negative-side outer weight body 356 is connected to the“ Y-axis ”. The other end of the Y-axis negative side intermediate bridging portion 352 is connected to the upper end of the “opposite surface to the negative inner weight body 355”, and the upper end of the “opposite surface to the pedestal 360” of the Y-axis negative outer weight body 356 is connected to Y. The shaft negative outer bridging portion 353 is connected, and grooves G4a and G4b extending in the direction perpendicular to the Y axis are formed on the upper surface of the Y-axis negative inner weight body 355 and the upper surface of the Y-axis negative outer weight body 356, respectively. Is formed.

  When such a structure is adopted as the support structure of the sub-vibrator, a U-shaped section is formed in the vibration energy transmission path, and this U-shaped section effectively prevents propagation of vibration energy. The point of fulfilling the function is as described above. In particular, in the case of the second embodiment, the U-shaped section is provided at two locations on the propagation path of vibration energy, so that a more remarkable vibration leakage suppressing effect can be obtained.

  Also in this basic structure 300, geometric symmetry is maintained in the arrangement of each component. That is, as shown in FIG. 17, the X-axis positive inner weight body 325, the Y-axis positive inner weight body 335, the X-axis negative inner weight body 345, and the Y-axis negative inner weight body 355. Is composed of weight bodies having the same shape and the same mass, and the arrangement of these four inner weight bodies is symmetrical with respect to both the XZ plane and the YZ plane. Similarly, the X-axis positive outer weight body 326, the Y-axis positive outer weight body 336, the X-axis negative outer weight body 346, and the Y-axis negative outer weight body 356 have the same shape and the same mass. The four outer weights are arranged symmetrically with respect to both the XZ plane and the YZ plane. Actually, not only the eight weight bodies but also the entire geometric structure of the basic structure 300 is symmetric with respect to both the XZ plane and the YZ plane. As described above, this symmetry contributes to suppression of vibration leakage.

  The structure of the basic structure 300 shown in FIGS. 17 and 18 and the vibration leakage suppressing effect have been described above. Actually, the basic structure 300 can be configured by performing an etching process or a mechanical cutting process on a semiconductor substrate such as silicon. In order to configure the angular velocity sensor, in addition to the basic structure 300, a driving unit that drives the central weight body 310 that functions as the main vibrator in the apparatus housing 380, and the central weight body 310 are provided. Detection means for detecting the acting Coriolis force and outputting the detected value as an angular velocity detection value around a predetermined axis is required. Here, an example in which a piezoelectric element is used as the driving unit and the detecting unit and a specific angular velocity sensor is configured will be described.

  FIG. 19 is a top view showing a state in which a piezoelectric element is attached to the basic structure 300 shown in FIG. 17 (hatching indicates a piezoelectric element, not a cross section). On the other hand, FIG. 20 is a cross-sectional side view of the basic structure 300 with a piezoelectric element shown in FIG. 19 cut along an XZ plane. As illustrated, the piezoelectric elements X11, X12, X13, and X14 are fixed on the X axis on the upper surface of the basic structure 300, and the piezoelectric elements Y11, Y12, Y13, and Y14 are fixed on the Y axis. ing.

  As shown in the figure, all of the eight piezoelectric elements are arranged on the inner connecting members (inner bridging portions 321, 331, 341, 351). This is because it functions as a driving means for driving the vibrator or a detecting means for detecting the displacement (displacement based on the Coriolis force) of the central weight body 310 (main vibrator). Also in the case of the second embodiment shown here, it is not necessary to actively drive the sub-vibrator and to detect the displacement of the sub-vibrator when performing the angular velocity detection operation. It is not necessary to dispose a piezoelectric element on the member (intermediate bridge portions 322, 332, 342, 352) or the outer connection member (outer bridge portions 323, 333, 343, 353).

  As illustrated, the piezoelectric elements X11, Y11, X14, and Y14 are disposed in the vicinity of the outer ends of the inner bridging portions 321, 331, 341, and 351 (the ends far from the central weight body 310), and the piezoelectric elements X12 and Y12 are disposed. , X13, and Y13 are arranged in the vicinity of the inner ends of the inner bridging portions 321, 331, 341, and 351 (ends close to the central weight body 310). This is because when the inner bridge portions 321, 331, 341, and 351 are bent due to the displacement of the central weight body 310, stress concentrates at both ends thereof, and a piezoelectric element is disposed at this position. This is because it is efficient both in driving the central weight body 310 and detecting the displacement of the central weight body 310.

  In the angular velocity sensor according to the second embodiment shown in FIGS. 19 and 20, periodic motion is performed on the central weight body 310 (main vibrator) using eight piezoelectric elements X11 to X14 and Y11 to Y14. The configuration of the drive means for performing the above and the configuration of the detection means for detecting the Coriolis force acting on the central weight body 310 (main vibrator) are the angular velocities according to the first embodiment shown in FIGS. In the sensor, the configuration of the driving means for causing the central weight body 210 (main vibrator) to perform periodic motion using the eight piezoelectric elements X11 to X14, Y11 to Y14, and the central weight body 210 Since it is completely the same as the structure of the detection means which detects the Coriolis force which acts on (main vibrator), the description is omitted here. Further, the various modifications described in §4 can be similarly applied to the second embodiment.

<<< §6. Angular velocity sensor according to the third embodiment of the present invention >>>
Here, an angular velocity sensor according to a third embodiment of the present invention will be described. The basic structure 200 (see FIG. 3) of the angular velocity sensor according to the first embodiment described so far and the basic structure 300 (see FIG. 17) of the angular velocity sensor according to the second embodiment have four main oscillators. Is supported by a beam structure, and a sub-vibrator is provided in the middle of the beam structure. On the other hand, the basic structure of the angular velocity sensor according to the third embodiment described here is that the entire periphery of the main vibrator is supported by the diaphragm structure.

  FIG. 21 is a top view showing the basic structure 400 of the angular velocity sensor according to the third embodiment, and FIG. 22 is a side sectional view. Comparing the side sectional view of FIG. 22 with the side sectional view of FIG. 18, it can be seen that they are very similar. The difference between the two is clearly shown in the top view. That is, as can be seen from the top view of FIG. 21, no window portion or bridge portion is formed on the top surface of the basic structure 400.

  Here too, for convenience of explanation, an XYZ three-dimensional coordinate system is defined in which the origin O is at the center position of the upper surface of the basic structure 400 and the upper surface of the basic structure 400 coincides with the XY plane. FIG. 22 corresponds to a side sectional view of the basic structure 400 shown in FIG. 21 taken along the XZ plane.

  The solid and broken circles shown in FIG. 21 are all concentric circles with the origin O as the center. In FIG. 21, solid circles indicate the outlines of the annular grooves G20 and G30 formed on the upper surface of the basic structure 400, as shown in the side sectional view of FIG. In FIG. 21, broken circles indicate the contour lines of the annular grooves G15, G25, and G35 formed on the lower surface of the basic structure 400, as shown in the side sectional view of FIG. is there.

  The planar structure of the basic structure 400 is clearly shown in FIGS. FIG. 23 is a cross-sectional plan view of the basic structure 400 shown in FIG. 22 taken along the cutting plane 23-23. As shown by a broken line, a cylindrical central weight body 410 is disposed at the center, and a washer-shaped inner plate-like structure 421 (inner connection member) is disposed so as to surround the center weight 410. Is provided with a washer-like intermediate plate structure 422 (intermediate connection member) with an annular groove portion G20 interposed therebetween, and on the outer side with a circular groove portion G30 with a washer-like outer plate structure 423 ( Outer connection member) is disposed, and a pedestal 460 is disposed further outside.

  On the other hand, FIG. 24 is a cross-sectional plan view of the basic structure shown in FIG. The shape of each weight body is clearly shown in FIG. That is, the central weight body 410 functioning as the main vibrator is a cylindrical structure, and an inner annular weight body 425 is disposed so as to surround the annular groove G15, and the outer side of the outer circumferential weight body 425 is disposed. An outer annular weight body 426 is disposed so as to surround the annular groove portion G25, and a pedestal 460 is disposed so as to surround the outer periphery of the annular groove portion G35. Here, the inner annular weight body 425 and the outer annular weight body 426 are both weight bodies that function as sub-vibrators.

  As is clear from the side sectional view of FIG. 22, each of the washer-like plate-like structures 421, 422, and 423 has flexibility because of its small thickness, and functions as a diaphragm. After all, in the basic structure 400 according to the third embodiment, the main vibrator is constituted by the central weight body 410, and the sub vibrator surrounds the central weight body 410 in a separated state. An annular weight body 425 and an outer annular weight body 426 surrounding the inner annular weight body in a separated state are constituted.

  Further, the inner plate-like structure 421 is arranged so as to surround the side surface of the central weight body 410, the inner portion is connected to the central weight body 410, and the outer portion is connected to the inner annular weight body 425. An inner connecting member is formed, and is arranged so as to surround the outer annular weight body 426. The outer plate-like structure body 423 in which the inner portion is connected to the outer annular weight body 426 and the outer portion is connected to the base 460. The outer connecting member is configured by the intermediate plate-like structure 422 having flexibility to connect the inner annular weight body 425 and the outer annular weight body 426, and the pedestal 460 The outer plate-like structure 423 surrounds the structure.

  As shown in FIG. 22, the bottom surface of the base 460 is fixed to the apparatus housing 480. Although only a part of the device housing 480 is illustrated, the device housing 480 is a housing that accommodates the entire basic structure 400. That is, the device housing 480 functions to support and fix the pedestal 460 and accommodate the central weight body 410 in a suspended state. Each connecting member that supports the central weight body 410 in a suspended state is a plate-like structure having a small thickness, and thus has flexibility and functions as a diaphragm. For this reason, when an external force is applied to the central weight body 410, each diaphragm is deflected, and the weight body 410 is displaced with respect to the base 460 (device housing 480). Of course, not only the weight body 410 that functions as the main vibrator, but also the inner annular weight body 425 and the outer annular weight body 426 that function as the sub-vibrator are in a displaceable state with a certain degree of freedom. .

  According to the experiments conducted by the inventors of the present application, even when the basic structure 400 according to the third embodiment is used, the vibration energy from the central weight body 410 functioning as the main vibrator to the device housing 480 is reduced. The effect of suppressing propagation was obtained. This is provided in the middle of a vibration energy transmission path (in this example, a diaphragm provided so as to surround the entire periphery of the central weight body 410), as in the embodiments described so far. This is because vibration energy is absorbed by the sub-vibrator.

  Also in the third embodiment, the connection positions of the plate-like structures 421, 422, and 423 having flexibility are the side surfaces of the inner annular weight body 425 and the outer annular weight body 426 that function as sub-vibrators. In addition, annular groove portions G20 and G30 are formed on the upper surface of each weight body.

  More specifically, as shown in FIG. 22, in the basic structure 400, the outer side of the inner plate-like structure 421 is disposed at the upper end of the “opposite surface to the central weight 410” of the inner annular weight 425. The inner portion of the intermediate plate-like structure 422 is connected to the upper end of the “opposite surface to the outer annular weight body 426” of the inner annular weight body 425, and the “inner annular weight of the outer annular weight body 426 is connected. The outer portion of the intermediate plate-like structure 422 is connected to the upper end of the “facing surface with respect to the weight body 425”, and the inner portion of the outer plate-like structure 423 is connected to the upper end of the “opposing surface with respect to the base 460” of the outer annular weight body 426. It is connected. An annular groove G20 is formed on the upper surface of the inner annular weight body 425 along the contour line of the upper surface of the inner annular weight body 425, and the outer annular weight 426 is formed on the upper surface of the outer annular weight body 426. An annular groove G30 is formed along the outline of the upper surface of the weight body 426.

  When such a structure is adopted as the support structure of the sub-vibrator, a U-shaped section is formed in the vibration energy transmission path as shown in the side sectional view of FIG. As described above, this part functions to effectively prevent propagation of vibration energy.

  Also in this basic structure 400, geometric symmetry is maintained in the arrangement of each component. That is, as shown in FIG. 24, the projected images of the inner annular weight body 425 and the outer annular weight body 426 on the XY plane have an annular shape with the origin O as the center, and the XZ plane and YZ Symmetrical with respect to both planes. In practice, the entire geometric structure of the basic structure 400 is symmetric with respect to both the XZ plane and the YZ plane. As described above, this symmetry contributes to suppression of vibration leakage.

  The structure of the basic structure 400 shown in FIGS. 21 and 22 and the vibration leakage suppressing effect have been described above. Actually, the basic structure 400 can be configured by, for example, performing an etching process or a mechanical cutting process on a semiconductor substrate such as silicon. In order to configure the angular velocity sensor, in addition to the basic structure 400, a driving means for driving the central weight body 410 functioning as the main vibrator in the apparatus housing 480, and the central weight body 410 are provided. Detection means for detecting the acting Coriolis force and outputting the detected value as an angular velocity detection value around a predetermined axis is required. Here, an example in which a piezoelectric element is used as the driving unit and the detecting unit and a specific angular velocity sensor is configured will be described.

  FIG. 25 is a top view showing a state in which a piezoelectric element is attached to the basic structure 400 shown in FIG. 21 (hatching indicates a piezoelectric element, not a cross section). On the other hand, FIG. 26 is a sectional side view of the basic structure 400 with a piezoelectric element shown in FIG. 25 cut along an XZ plane. As illustrated, the piezoelectric elements X41, X42, X43, and X44 are fixed on the X axis on the upper surface of the basic structure 400, and the piezoelectric elements Y41, Y42, Y43, and Y44 are fixed on the Y axis. ing.

  As shown in the drawing, all of the eight piezoelectric elements are arranged on the inner connecting member (inner plate-like structure 421). This is because it functions as a driving means for driving or a detecting means for detecting displacement (displacement based on Coriolis force) of the central weight body 410 (main vibrator). Also in the case of the third embodiment shown here, it is not necessary to actively drive the sub-vibrator and to detect the displacement of the sub-vibrator in performing the angular velocity detection operation. There is no need to dispose a piezoelectric element on the member (intermediate plate-like structure 422) or the outer connecting member (outer plate-like structure 423).

  As illustrated, the piezoelectric elements X41, Y41, X44, and Y44 are disposed in the vicinity of the outer end portion (the end far from the central weight body 410) of the inner plate-like structure 421, and the piezoelectric elements X42, Y42, X43, and Y43. Is disposed in the vicinity of the inner end of the inner plate-like structure 421 (the end close to the central weight body 410). This is because, when the inner plate-like structure 421 is bent due to the displacement of the central weight body 410, stress concentrates at both ends thereof. If a piezoelectric element is arranged at this position, the central portion This is because it is efficient both in driving the weight body 410 and detecting the displacement of the central weight body 410.

  In the angular velocity sensor according to the third embodiment shown in FIGS. 25 and 26, periodic motion is performed on the central weight body 410 (main vibrator) using eight piezoelectric elements X41 to X44 and Y41 to Y44. The configuration of the drive means for performing the above and the configuration of the detection means for detecting the Coriolis force acting on the central weight body 410 (main vibrator) are the angular velocities according to the first embodiment shown in FIGS. In the sensor, the configuration of the driving means for causing the central weight body 210 (main vibrator) to perform periodic motion using the eight piezoelectric elements X11 to X14, Y11 to Y14, and the central weight body 210 Since it is completely the same as the structure of the detection means which detects the Coriolis force which acts on (main vibrator), the description is abbreviate | omitted here. Further, the various modifications described in §4 can be similarly applied to the third embodiment.

  In §6, an example in which a pair of annular sub-vibrators 425 and 426 are provided so as to surround the main vibrator 410 is described. However, two sub-vibrators are not necessarily provided, and one sub-vibrator is not necessarily provided. Only the vibrator may be provided. In this case, the main vibrator is constituted by the central weight body, the inner connecting member is constituted by the inner plate-like structure surrounding the side face of the central weight body, and the sub-vibrator is further formed by the inner plate-like structure. What is necessary is just to comprise by the annular weight body which surrounds a structure body, an outer side connection member is comprised by the outer side plate-shaped structure surrounding this annular weight body, and a pedestal by the structure body which surrounds this outer side plate-like structure body.

  Thus, even when the sub-vibrator is constituted by only one annular weight body, the outer portion of the inner plate-like structure is connected to the upper end of the “opposite surface to the central weight body” of the annular weight body. The inner portion of the outer plate-like structure is connected to the upper end of the “opposite surface to the pedestal” of the annular weight body, and a groove portion is formed on the upper surface of the annular weight body along the contour line of the upper surface. This is preferable because the effect of suppressing vibration leakage can be enhanced. Further, when an XYZ three-dimensional coordinate system having the origin O at the center position of the upper surface of the central weight body is defined, the basic structure has an upper surface along the XY plane of the coordinate system, and the XY of the annular weight body If the projected image on the plane has an annular shape with the origin O as the center, geometric symmetry can be ensured, which is also preferable for enhancing the effect of suppressing vibration leakage.

<<< §7. Angular velocity sensor according to the fourth embodiment of the present invention >>>
Subsequently, an angular velocity sensor according to a fourth embodiment of the present invention will be described. FIG. 27 is a top view showing a basic structure 500 of an angular velocity sensor according to the fourth embodiment, and FIG. 28 is a side sectional view. Again, for convenience of explanation, an XYZ three-dimensional coordinate system is defined in which the origin O is at the center position of the upper surface of the basic structure 500 and the upper surface of the basic structure 500 coincides with the XY plane. FIG. 28 corresponds to a side sectional view of the basic structure 500 shown in FIG. 27 taken along the XZ plane.

  As shown in FIG. 27, the basic structure 500 is formed with fan-shaped windows W11 to W42. In this respect, the basic structure 200 of the angular velocity sensor according to the first embodiment (FIG. 3). And the basic structure 300 (see FIG. 17) of the angular velocity sensor according to the second embodiment. That is, the central weight body 510 serving as the main vibrator is supported by the beam structure from its four sides, and a structure in which the sub vibrator is provided in the middle of the beam structure is adopted. However, the sub-vibrator is constituted by a single annular weight body 525. As described above, the sub-vibrator is constituted by an annular weight body surrounding the main vibrator. The basic structure 400 (see FIG. 24) of the angular velocity sensor according to the third embodiment described above. ).

  As shown in the top view of FIG. 27, the central weight body 510 constituting the main vibrator is a cylindrical weight body, and four beam structures provided on the top, bottom, left, and right in the figure. Is supported by the pedestal 560. And the sub-vibrator comprised by the single cyclic | annular weight body 525 is connected to center vicinity of each of the four beam structures. In short, in the basic structure 200 according to the first embodiment shown in FIG. 3, a single annular weight body is formed by sequentially connecting four weight bodies constituting the sub-vibrator in an annular manner. Can be considered to correspond to the basic structure 500 shown in FIG.

  That is, for the X-axis positive side, the central weight 510 and the single annular weight 525 are connected by the X-axis positive inner bridging portion 521, and the X-axis positive-side outer bridging portion 522 connects the single weight. One annular weight body 525 and a base 560 are connected. On the Y axis positive side, a central weight body 510 and a single annular weight body 525 are connected by a Y axis positive side inner bridge portion 531. And a single annular weight body 525 and a base 560 are connected by the Y-axis positive-side outer bridge portion 532, and the X-axis negative side is centered by the X-axis negative-side inner bridge portion 541. The part weight 510 and the single annular weight 525 are connected, and the single annular weight 525 and the pedestal 560 are connected by the X-axis negative outer bridge portion 542, and the Y-axis negative For the side, the central weight of the Y-axis negative inner bridge 551 And body 510 and the single annular weight body 525 is connected by the Y-axis negative side outer bridge portion 552, are connected with a single annular weight body 525 and the pedestal 560.

  As shown in FIG. 27, the outer contour line of the central weight body 510, the inner and outer contour lines of the single annular weight body 525, and the inner contour line of the base 560 are all centered on the origin O. It is a concentric circle. In the embodiment shown here, no groove is formed on the upper surface of the single annular weight body 525. Of course, an annular groove along the contour line may be formed here. Absent.

  As described above, in the basic structure 500 shown in FIGS. 27 and 28, the main vibrator is configured by the cylindrical central weight body 510, and the sub vibrator separates the central weight body 510. It is comprised by the single cyclic | annular weight body 525 surrounding in a state. The bottom surface of the pedestal 560 is fixed to the apparatus housing 580. Although only a part of the device housing 580 is illustrated, the device housing 580 is a housing that accommodates the entire basic structure 500. That is, the device housing 580 functions to support and fix the pedestal 560 and accommodate the central weight body 510 in a suspended state.

  The connecting member that supports the central weight body 510 in a suspended state is constituted by each bridging portion having flexibility. For this reason, when an external force is applied to the central weight body 510, the bridge portions are bent, and the weight body 510 is displaced with respect to the pedestal 560 (device housing 580). Of course, not only the weight body 510 that functions as the main vibrator but also the annular weight body 525 that functions as the sub-vibrator is displaceable with a certain degree of freedom.

  According to the experiment conducted by the inventors of the present application, even when the basic structure 500 according to the fourth embodiment is used, the vibration energy from the central weight body 510 functioning as the main vibrator to the device housing 580 is reduced. The effect of suppressing propagation was obtained. This is the same as the embodiment described so far, and the sub-path provided in the middle of the vibration energy transmission path (in this example, four beam structures connected to the central weight 510). This is probably because vibration energy is absorbed by the vibrator.

  Also in the fourth embodiment, the connection position of each bridging portion 521, 522, 531, 532, 541, 542, 551, 552 to the annular weight body 525 is the upper end of the side surface of the annular weight body 525. Yes. In the illustrated embodiment, no groove is formed on the upper surface of the annular weight body 525. However, if an annular groove section is formed along the contour line of the annular weight body 525, the transmission path for vibration energy is formed. A U-shaped section is formed, and the propagation of vibration energy can be more effectively prevented.

  Also in this basic structure 500, geometric symmetry is maintained in the arrangement of each component, and the entire geometric structure of this basic structure 500 is symmetric with respect to both the XZ plane and the YZ plane. It has become. As described above, this symmetry contributes to suppression of vibration leakage.

  The structure of the basic structure 500 shown in FIGS. 27 and 28 and the vibration leakage suppressing effect have been described above. Actually, the basic structure 500 can be configured by, for example, performing an etching process or a mechanical cutting process on a semiconductor substrate such as silicon. In order to configure the angular velocity sensor, in addition to the basic structure 500, a driving means for driving a central weight 510 that functions as a main vibrator in the device housing 580, and a central weight 510 are provided. Detection means for detecting the acting Coriolis force and outputting the detected value as an angular velocity detection value around a predetermined axis is required. Here, an example in which a piezoelectric element is used as the driving unit and the detecting unit and a specific angular velocity sensor is configured will be described.

  FIG. 29 is a top view showing a state where a piezoelectric element is attached to the basic structure 500 shown in FIG. 27 (hatching indicates a piezoelectric element, not a cross section). On the other hand, FIG. 30 is a side sectional view of the basic structure with a piezoelectric element 500 shown in FIG. 29 cut along the XZ plane. As illustrated, piezoelectric elements X51, X52, X53, and X54 are fixed on the X-axis on the upper surface of the basic structure 500, and piezoelectric elements Y51, Y52, Y53, and Y54 are fixed on the Y-axis. ing.

  As shown in the figure, all of the eight piezoelectric elements are arranged on the inner connecting members (inner bridging portions 521, 531, 541, 551). This is because it functions as a driving means for driving the vibrator or a detecting means for detecting the displacement (displacement based on the Coriolis force) of the central weight 510 (main vibrator). Also in the case of the fourth embodiment shown here, it is not necessary to actively drive the sub-vibrator and to detect the displacement of the sub-vibrator in performing the angular velocity detection operation. There is no need to dispose a piezoelectric element on the member (outer bridge portions 522, 532, 542, 552).

  As illustrated, the piezoelectric elements X51, Y51, X54, and Y54 are disposed in the vicinity of the outer ends of the inner bridging portions 521, 531, 541, and 551 (ends far from the central weight body 510), and the piezoelectric elements X52 and Y52 are disposed. , X53, Y53 are arranged in the vicinity of the inner ends of the inner bridging portions 521, 531, 541, 551 (ends close to the central weight body 510). This is because, when the inner bridge portions 521, 531, 541, and 551 are bent due to the displacement of the central weight body 510, stress concentrates at both ends thereof, and thus a piezoelectric element is disposed at this position. This is because it is efficient both in driving the central weight body 510 and detecting the displacement of the central weight body 510.

  In the angular velocity sensor according to the fourth embodiment shown in FIGS. 29 and 30, a periodic motion is performed on the central weight body 510 (main vibrator) using eight piezoelectric elements X51 to X54 and Y51 to Y54. The configuration of the drive means for performing the above and the configuration of the detection means for detecting the Coriolis force acting on the central weight body 510 (main vibrator) are the angular velocities according to the first embodiment shown in FIGS. In the sensor, the configuration of the driving means for causing the central weight body 210 (main vibrator) to perform periodic motion using the eight piezoelectric elements X11 to X14, Y11 to Y14, and the central weight body 210 Since it is completely the same as the structure of the detection means which detects the Coriolis force which acts on (main vibrator), the description is abbreviate | omitted here. Further, the various modifications described in §4 can be similarly applied to the third embodiment.

  Here, an example in which a single annular weight body 525 surrounding the main vibrator 510 is prepared as a sub vibrator has been described, but the sub vibrator may be constituted by a plurality of annular weight bodies. Absent. For example, in the basic structure 500 shown in FIG. 27, another annular weight body that surrounds the annular weight body 525 in a separated state is prepared, and is arranged between the annular weight body 525 and the pedestal 560. And you may make it join to the center part of each outer side bridge | crosslinking part 522,532,542,552. In this case, the main vibrator 510 has a structure surrounded by a sub vibrator made of a double annular weight body.

<<< §8. Angular velocity sensor according to the reference example without the arrangement of the sub-vibrator >>>
The basic concept of the present invention is that a sub-vibrator is provided in the middle of the flexible connecting member that supports the main vibrator with respect to the pedestal, and the vibration energy due to the periodic motion of the main vibrator is absorbed by the sub-vibrator. This is to suppress the occurrence of vibration leakage in the apparatus housing. Therefore, in implementing the present invention, a sub-vibrator having a certain mass is an indispensable element.

  However, according to an experiment conducted by the inventors of the present application, even if a U-shaped section is formed on the connection member that connects the main vibrator and the pedestal without providing the sub-vibrator, the pedestal can be obtained. It has been found that the effect of suppressing the vibration leakage of a certain degree can be obtained. Therefore, here, a basic structure in which the arrangement of the sub vibrator is omitted is introduced as a reference example.

FIG. 31 is a side sectional view showing a basic structure 200 ^* of an angular velocity sensor shown as a reference example. This basic structure 200 ^* is a U-shape in which each of the weight bodies 225, 235, 245, and 255 functioning as sub-vibrators in the basic structure 200 shown in FIGS. 3 and 4 has a U-shaped cross section. The bridge portions are replaced with 225 ^* , 235 ^* , 245 ^* , and 255 ^* (groove portions G1 to G4 are formed in the upper portion, respectively). In Figure 31, the right side portion of the center weight body 210, the bridge portion 221 and 225 ^*, is connected to the base 260 via 222, left side portion of the center weight body 210, bridge 241, 245 ^*, It is connected to the pedestal 260 via 242. Although not shown in FIG. 31, the back side and the near side of the central weight body 210 are similarly connected to the pedestal 260 via the bridging portion.

The substructure having a certain mass is not provided in the basic structure 200 ^* shown in FIG. 31, but U-shaped bridging portions 225 ^* , 235 ^* , 245 ^* , 255 ^* are formed in the middle. Therefore, as compared with the conventional basic structure 100 shown in FIGS. 1 and 2, the phenomenon (vibration leakage) in which the vibration energy generated by the periodic motion of the central weight body 210 escapes to the pedestal 260 side is suppressed. An effect is obtained. This is because if a U-shaped bridge portion 225 ^* , 235 ^* , 245 ^* , 255 ^* having a U-shaped cross-section is provided in the vibration energy transmission path, vibration is caused by bending deformation of the U-shaped bridge portion. This is probably because energy is absorbed.

FIG. 32 is a side sectional view showing a basic structure 300 ^* of an angular velocity sensor shown as another reference example. This basic structure 300 ^* has weights 325, 326, 335, 336, 345, 346, 355, and 356 that function as sub-vibrators in the basic structure 300 shown in FIGS. In the U-shaped bridge portions 325 ^* , 326 ^* , 335 ^* , 336 ^* , 345 ^* , 346 ^* , 355 ^* , 356 ^* (each having groove portions G1a to G4b formed on the upper part). It is a replacement. In Figure 32, the right side portion of the center weight body 310, bridge 321, 325 ^*, 322, 326 ^*, is connected to the base 360 via 323, left side portion of the center weight body 310, the bridge portion It is connected to the pedestal 360 via 341,345 ^* , 342,346 ^* , 343. Although not shown in FIG. 31, the back side and the near side of the central weight body 310 are similarly connected to the pedestal 360 via the bridging portion.

The basic structure 300 ^* shown in FIG. 32 has two vibration energy transmission paths from the central weight body 310 functioning as a vibrator to the pedestal 360, as compared with the basic structure 200 ^* shown in FIG. Since the U-shaped bridge portion is formed, the effect of suppressing vibration leakage becomes more remarkable. Of course, it is also possible to form a large number of U-shaped bridging portions by the transmission path of vibration energy.

<<< §9. Angular velocity sensor that moves sub-oscillator in reverse direction >>
As already described, in the basic structure used for the angular velocity sensor according to the present invention, the sub-vibrator is provided in the middle of the flexible connecting member that supports the main vibrator with respect to the pedestal. It is possible to absorb the vibration energy caused by the sub-vibrator and suppress the occurrence of vibration leakage in the apparatus housing via the pedestal. However, in the embodiments described so far, the sub-vibrator performs only a passive function, and does not perform an active action for eliminating vibration leakage. Here, in the angular velocity sensors according to various embodiments described so far, a device for causing the sub-vibrator to have an active action and effectively eliminating the vibration leakage will be described.

  The basic concept of the device described in §9 is that the main vibrator is driven so as to perform a periodic motion in the apparatus housing, and the sub-vibrator moves in the direction opposite to the movement of the main vibrator in the apparatus housing. It is in the point of driving.

  For example, as shown in FIG. 33, a simple model having a main vibrator 91 and a sub vibrator 92 and a connecting member 93 having flexibility for connecting them to each other is placed in an XYZ three-dimensional coordinate system. Let's consider the situation. Here, to detect the angular velocity, the main vibrator 91 is simply vibrated in the Z-axis direction, and the Coriolis force acting on the main vibrator 91 at that time is detected. In this case, not only the main vibrator 91 is caused to vibrate in the Z-axis direction but also the sub-vibrator 92 is caused to vibrate in the Z-axis direction. However, the direction of movement of the main vibrator 91 and the direction of movement of the sub-vibrator 92 are always reversed.

  Specifically, as shown in FIG. 34, when a force + Fz for displacing the main vibrator 91 in the positive Z-axis direction is applied, the sub-vibrator 92 is displaced in the negative Z-axis direction. As shown in FIG. 35, when the force −Fz is applied to the main vibrator 91 so as to be displaced in the negative Z-axis direction as shown in FIG. A force + Fz for displacing in the positive direction may be applied.

  According to experiments conducted by the inventors of the present application, in the basic structures according to the various embodiments described so far, when the main vibrator and the sub-vibrator perform such complementary movement, the pedestal is It has become possible to further reduce the vibration leakage transmitted to the device casing. In particular, when the mass of the main vibrator and the mass of the sub vibrator were set to be equal, a remarkable effect was seen in reducing vibration leakage. This is presumably because the two weight bodies having the same mass are simultaneously moved with velocity components having different directions and equal absolute values, thereby canceling out the vibration component leaking to the pedestal side.

  An example of a specific method for applying such a device to the various embodiments described so far will be described below. The basic structure according to the embodiments described so far includes a main vibrator, a sub-vibrator arranged adjacent to the main vibrator, a pedestal arranged adjacent to the sub-vibrator, and a main vibrator. An inner connecting member having flexibility for connecting the vibrator and the sub vibrator and an outer connecting member having flexibility for connecting the sub vibrator and the pedestal are provided. Therefore, AC driving signals are respectively supplied to the main driving piezoelectric element fixed to the surface of the inner connecting member, the sub driving piezoelectric element fixed to the surface of the outer connecting member, and the main driving piezoelectric element and the sub driving piezoelectric element. The drive control circuit that supplies the drive means constitutes the drive means, detects the detection piezoelectric element fixed on the surface of the inner connecting member, and detects the electric charge generated in the detection piezoelectric element, and detects the angular velocity based on the detection result The detection means is constituted by an angular velocity detection circuit that outputs a value. Then, the main vibrator can be driven by the main driving piezoelectric element, and the sub vibrator can be driven by the sub driving piezoelectric element. By adjusting the AC drive signal supplied to the main drive piezoelectric element and the sub drive piezoelectric element by the drive control circuit, the movement direction of the main vibrator and the movement direction of the sub vibrator can always be reversed. Is possible.

  FIG. 36 is a top view showing a basic structure with a piezoelectric element of an angular velocity sensor according to a fifth embodiment of the present invention (hatching indicates a piezoelectric element and does not indicate a cross section). 37 is a side sectional view of the basic structure with a piezoelectric element shown in FIG. 36 taken along the XZ plane. The basic structure 500 used in the fifth embodiment is exactly the same as the basic structure 500 used in the fourth embodiment described in §7. The difference between the fourth embodiment shown in FIGS. 29 and 30 and the fifth embodiment shown in FIGS. 36 and 37 is only the configuration of the piezoelectric element and the circuit configuration used by being connected to this piezoelectric element. is there.

  That is, in the fifth embodiment shown in FIGS. 36 and 37, in addition to the eight piezoelectric elements X51 to X54 and Y51 to Y54 shown in the fourth embodiment shown in FIGS. Piezoelectric elements x51 to x54, y51 to y54 are provided. Here, each of the piezoelectric elements X51 to X54 and Y51 to Y54 bearing the capital letter X or Y is a piezoelectric element fixed to the surface of the inner connecting member (inner bridging portions 521, 531, 541, 551). Or used as a main driving piezoelectric element for driving the main vibrator 510, or used as a main detecting piezoelectric element for detecting a Coriolis force (displacement of the main vibrator 510) acting on the main vibrator 510. be able to. On the other hand, the piezoelectric elements x51 to x54 and y51 to y54 bearing the lowercase alphabetic letter x or y are all piezoelectric elements fixed to the surface of the outer connecting member (outer bridge portions 522, 532, 542, and 552). It can be used as a sub driving piezoelectric element for driving the sub vibrator 525 or as a sub detecting piezoelectric element for detecting a Coriolis force (displacement) acting on the sub vibrator 525. Here, for the sake of convenience, the following description will be made on the assumption that all the 16 piezoelectric elements in total are piezoelectric elements having the polarization characteristics shown in FIG.

  FIG. 38 is a circuit diagram showing an example of a circuit used in the angular velocity sensor having the basic structure 500 with a piezoelectric element shown in FIG. 36 and FIG. In the angular velocity sensor using the circuit shown in FIG. 38, the four piezoelectric elements X52, X53, Y52, Y53 shown at the upper left of the circuit diagram are used as the main driving piezoelectric elements for driving the main vibrator 510. The four piezoelectric elements x52, x53, y52, and y53 shown in the upper right of the circuit diagram are used as sub-driving piezoelectric elements for driving the sub-vibrator 525.

  Here, the method of driving the main vibrator 510 using the main drive piezoelectric elements X52, X53, Y52, Y53 is the main vibrator 210 in the angular velocity sensor according to the first embodiment shown in FIGS. Is exactly the same as the method of driving. For example, if the main vibrator 510 is caused to vibrate in the Z-axis direction, the AC voltage signal φ1 shown in FIG. 10 (a) may be supplied to the main driving piezoelectric elements X52, X53, Y52, and Y53. . On the other hand, the method of driving the sub-vibrator 525 using the sub-drive piezoelectric elements x52, x53, y52, y53 is basically the same as the angular velocity sensor according to the first embodiment shown in FIGS. This is the same as the method for driving the main vibrator 210. However, since the direction of movement of the sub-vibrator 525 must always be opposite to the direction of movement of the main vibrator 510, the main driving piezoelectric elements X52, X53, Y52, and Y53 are shown in FIG. When the AC voltage signal φ1 shown in FIG. 10 is supplied, the AC voltage signal φ2 shown in FIG. 10B is supplied to the sub-driving piezoelectric elements x52, x53, y52, and y53.

  The drive control circuit 35 shown in FIG. 38 generates AC voltage signals φ1 and φ2 shown in FIGS. 10A and 10B based on the AC signal from the AC signal source 31, and one of them is a piezoelectric element for main drive. It functions to supply to X52, X53, Y52, Y53 and supply the other to the sub-driving piezoelectric elements x52, x53, y52, y53. If the polarization characteristics of the sub-drive piezoelectric elements x52, x53, y52, and y53 are reversed from those of the main drive piezoelectric elements X52, X53, Y52, and Y53 (that is, the characteristics shown in FIG. 7). If the sub-driving piezoelectric elements x52, x53, y52, y53 are constituted by piezoelectric elements having the opposite characteristics), the main driving piezoelectric elements X52, X53, Y52, Y53 and the sub-driving piezoelectric elements x52, x53, By supplying the same AC voltage signal (for example, φ1) to both y52 and y53, the main vibrator 510 and the sub vibrator 525 can be moved in opposite directions.

  By the way, as already described, even if the periodic AC voltage signal φ1 as shown in FIG. 8A is supplied, the actual periodic displacement of the vibrator is slightly as shown in FIG. 8B. This is followed by the delay time d. Accordingly, as shown in FIGS. 10 (a) and 10 (b), AC voltage signals φ1 and φ2 having opposite phases are supplied to the main driving piezoelectric element and the sub driving piezoelectric element, and the main vibrator and the sub vibration are supplied. In order to ensure that the direction of motion with respect to the child is always opposite, each part of the basic structure 500 is designed so that the delay time d for the main oscillator and the delay time d for the sub-vibrator coincide. There is a need to. Alternatively, when the delay times d of the two are different, the drive control circuit 35 may be provided with the adjustment function. For example, with respect to the AC voltage signal φ1 shown in FIG. 10A, the time axis of the AC voltage signal φ2 shown in FIG.

  Further, as described above, it is preferable to set the mass of the main vibrator 510 and the mass of the sub vibrator 525 to be equal. However, in practice, the effect of suppressing vibration leakage can be obtained even if the delay time d of the two is slightly different or the mass of the two is slightly different.

  Now, the four piezoelectric elements X51, X54, Y51, Y54 shown in the lower left of the circuit diagram of FIG. 38 are used as the main detecting piezoelectric elements for detecting the displacement (acted Coriolis force) of the main vibrator 510. The four piezoelectric elements x51, x54, y51, y54 shown in the lower right of the circuit diagram are used as sub-detecting piezoelectric elements for detecting the displacement (acted Coriolis force) of the sub-vibrator 525. .

  Here, the method for detecting the Coriolis force acting on the main vibrator 510 using the main detection piezoelectric elements X51, X54, Y51, Y54 is the angular velocity sensor according to the first embodiment shown in FIGS. The method for detecting the Coriolis force acting on the main vibrator 210 is exactly the same. For example, in the state where the main vibrator 510 and the sub vibrator 525 are vibrated in the Z-axis direction, when an angular velocity is applied, a Coriolis force is applied according to the applied angular velocity. For example, if the angular velocity ωy about the Y axis is applied, the direction of motion of the main vibrator 510 is the Z axis direction, so the Coriolis force Fx in the X axis direction is applied. When the Coriolis force + Fx in the X-axis positive direction acts, the main vibrator 510 tilts in the X-axis positive direction. When the Coriolis force -Fx in the X-axis negative direction acts, the main vibrator 510 Tilts in the negative direction of the X axis.

  Such an inclination of the main vibrator 510 in the X-axis direction can be detected as charges generated by the main detecting piezoelectric elements X51 and X54. That is, based on the Coriolis force + Fx in the X-axis positive direction, when the main vibrator 510 tilts in the X-axis positive direction, the piezoelectric element X51 contracts, the piezoelectric element X54 extends, and the X-axis negative direction Coriolis force -Fx. When the main vibrator 510 is tilted in the negative direction of the X axis, the piezoelectric element X51 expands and the piezoelectric element X54 contracts, so that a difference occurs between the voltage values V (X51) and V (X54) shown in FIG. The difference is obtained as a voltage value by 21. This voltage value is a detection value indicating the angular velocity ωy about the Y axis.

  Similarly, the inclination of the main vibrator 510 in the Y-axis direction due to the action of the angular velocity ωx around the X-axis can be detected as the generated charges of the main detection piezoelectric elements Y51 and Y54. That is, based on the Coriolis force + Fy in the Y-axis positive direction, when the main vibrator 510 tilts in the Y-axis positive direction, the piezoelectric element Y51 contracts, the piezoelectric element Y54 extends, and the Y-axis negative direction Coriolis force -Fy. When the main vibrator 510 tilts in the negative Y-axis direction, the piezoelectric element Y51 expands and the piezoelectric element Y54 contracts, so that a difference occurs between the voltage values V (Y51) and V (Y54) shown in FIG. The difference is obtained as a voltage value by 22. This voltage value is a detected value indicating the angular velocity ωx about the X axis.

  The angular velocity detection circuit 45 shown in FIG. 38 has a function of detecting and outputting the angular velocities ωx and ωy in this way. Note that the angular velocity detection timing is as already described in Section 3.

  On the other hand, such angular velocity detection can be performed not only based on the Coriolis force acting on the main vibrator 510 but also based on the Coriolis force acting on the sub vibrator 525. The components shown on the right side of the angular velocity detection circuit 45 shown in FIG. 38 are elements for detecting the Coriolis force acting on the sub vibrator 525.

  For example, consider the case where the Coriolis force in the X-axis direction acts on the sub-vibrator 525 because the angular velocity ωy around the Y-axis acts. In this case, when the sub-vibrator 525 is tilted in the X-axis positive direction based on the Coriolis force + Fx in the X-axis positive direction, the piezoelectric element x51 is contracted, the piezoelectric element x54 is expanded, and the Coriolis force -Fx in the X-axis negative direction Based on this, when the sub vibrator 525 tilts in the negative direction of the X-axis, the piezoelectric element x51 expands and the piezoelectric element x54 contracts, so that a difference occurs between the voltage values V (x51) and V (x54) shown in FIG. The difference is obtained as a voltage value by the circuit 23. This voltage value is a detection value indicating the angular velocity ωy about the Y axis.

  Similarly, the tilt in the Y-axis direction of the sub vibrator 525 caused by the action of the angular velocity ωx around the X axis can be detected as generated charges of the sub-detecting piezoelectric elements y51 and y54. That is, based on the Coriolis force + Fy in the Y-axis positive direction, when the sub-vibrator 525 tilts in the Y-axis positive direction, the piezoelectric element y51 contracts, the piezoelectric element y54 extends, and the Y-axis negative direction Coriolis force -Fy. When the sub-vibrator 525 is tilted in the negative Y-axis direction, the piezoelectric element y51 expands and the piezoelectric element y54 contracts, so that a difference occurs between the voltage values V (y51) and V (y54) shown in FIG. The difference is obtained as a voltage value by 24. This voltage value is a detected value indicating the angular velocity ωx about the X axis.

  As described above, the angular velocity detection circuit 45 shown in FIG. 38 has a function of detecting the angular velocities ωx and ωy based on the Coriolis force acting on the main vibrator 510 and an angular velocity ωx based on the Coriolis force acting on the sub vibrator 525. , Ωy are both provided. However, since the main vibrator 510 and the sub vibrator 525 are moving in opposite directions, the angular velocity ωy indicated by the output voltage of the difference circuit 21 and the angular velocity ωy indicated by the output voltage of the difference circuit 23 are signs. Therefore, it should be noted that the angular velocity ωx indicated by the output voltage of the difference circuit 22 and the angular velocity ωx indicated by the output voltage of the difference circuit 24 have opposite signs.

  Of course, it is sufficient to perform either one of the angular velocity detection based on the Coriolis force acting on the main vibrator 510 and the angular velocity detection based on the Coriolis force acting on the sub-vibrator 525. It is preferable that the average value is output as final angular velocity detection values ωx, ωy.

  Eventually, the driving means causes the main vibrator and the sub-vibrator to vibrate with the same amplitude and the same frequency in the direction parallel to the predetermined common vibration axis, respectively. Is always in the opposite direction, and if the absolute value of the movement speed of the main vibrator and the absolute value of the movement speed of the sub-vibrator are equal, the effect of suppressing vibration leakage to the device casing is further improved. It becomes possible to increase.

  In addition, in the case of the angular velocity sensor using the basic structure according to the various embodiments described so far, it is possible to improve the detection sensitivity by devising that the sub vibrator is driven in the direction opposite to the main vibrator. It has been found that a secondary effect of “encouraging” can also be obtained. The following explains why this secondary effect is obtained.

  FIG. 39 is a side sectional view showing an example of a driving state of the angular velocity sensor described above. The figure shows a state in which a Coriolis force + Fx in the X-axis positive direction acts on the main vibrator 510 and a Coriolis force -Fx in the X-axis negative direction acts on the sub-vibrator 525. . Since the drive control is performed so that the movement direction of the main vibrator 510 and the movement direction of the sub-vibrator 525 are always opposite to each other, when an angular velocity is applied, the direction of the Coriolis force generated due to the angular velocity is The main vibrator 510 and the sub vibrator 525 are always reversed. Accordingly, when the Coriolis force + Fx in the X-axis positive direction acts on the main vibrator 510 due to some angular velocity, as shown in the drawing, the Coriolis force -Fx in the X-axis negative direction is exerted on the sub-oscillator 525. Will act.

  At this time, considering the stress acting on the attention points Q1 to Q4 (one point on the upper surface of the basic structure 500) indicated by arrows in the figure, the stress generated at each position of each of the attention points Q1 to Q4 is the sub vibrator 525. As compared with the case where the is not driven, it increases. This is because the stress generated when the main vibrator 510 moves in the right direction in the figure overlaps with the stress generated when the sub vibrator 525 moves in the left direction in the figure. For this reason, if a piezoelectric element arranged in the vicinity of the points of interest Q1 to Q4 is used as a piezoelectric element for detection, detection with higher sensitivity can be performed. This is exactly the same when the Coriolis force in the Y-axis direction acts on the main vibrator 510 and the sub vibrator 525.

  Further, even when a Coriolis force in the Z-axis direction acts on the main vibrator 510 and the sub vibrator 525, detection with high sensitivity is possible. FIG. 40 shows a state in which a Coriolis force + Fz in the Z-axis positive direction acts on the main vibrator 510 and a Coriolis force −Fz in the Z-axis negative direction acts on the sub-vibrator 525. . Also in this case, considering the stress acting on the points of interest Q1 to Q4 (one point on the upper surface of the basic structure 500) indicated by arrows in the drawing, the stress generated at each position of the points of interest Q1 to Q4 is the sub-vibrator. It will increase compared with the case where 525 is not driven. This is because the stress generated when the main vibrator 510 moves upward in the figure and the stress generated when the sub vibrator 525 moves downward in the figure overlap. For this reason, if a piezoelectric element arranged in the vicinity of the points of interest Q1 to Q4 is used as a piezoelectric element for detection, detection with higher sensitivity can be performed.

  Note that the idea of driving the sub-vibrator in the direction opposite to that of the main vibrator is not limited to the case where each vibrator is simply oscillated, but can also be applied to a case where the sub-vibrator is moved in a circular motion. In this case, the driving means causes the main vibrator and the sub-vibrator to circularly move in the same cycle in opposite directions on a specific motion plane parallel to a predetermined common reference plane, respectively. The direction and the direction of motion of the sub-vibrator may always be opposite to each other, and the absolute value of the motion speed of the main vibrator and the absolute value of the motion speed of the sub-vibrator may be equal.

  Specifically, in §4-2, the modification shown in FIG. 11 can be used to cause the main vibrator to oscillate in an arbitrary coordinate axis direction or to move circularly along an arbitrary coordinate plane. I explained that. Using the same principle, for example, if an angular velocity sensor as shown in the top view of FIG. 41 is used, the main vibrator is simply oscillated in an arbitrary coordinate axis direction or circularly moved along an arbitrary coordinate plane. At the same time, the sub-vibrator can be moved in the opposite direction to the main vibrator.

  The angular velocity sensor shown in FIG. 41 has 48 piezoelectric elements arranged on the upper surface of the basic structure 500 shown in FIG. In FIG. 41, hatching indicates a piezoelectric element and does not indicate a cross section.

  Also in this figure, for convenience of explanation, an Xa axis and an Xb axis that are parallel to the X axis and arranged at a predetermined interval are defined on both sides of the X axis, and the Y axis is defined on both sides of the Y axis. The Ya axis and the Yb axis are defined in parallel to each other and at a predetermined interval. The Xa axis and the Xb axis are defined at positions symmetrical with respect to the X axis, and the Ya axis and the Yb axis are defined at positions symmetrical with respect to the Y axis.

  In the example shown here, as shown in the figure, piezoelectric elements X51 to X54 are arranged on the inner part on the X axis, and piezoelectric elements X61 to X64 are arranged on the inner part on the Xa axis, and on the Xb axis. Piezoelectric elements X71 to X74 are disposed in the inner portion. Piezoelectric elements Y51 to Y54 are disposed on the inner part on the Y axis, piezoelectric elements Y61 to Y64 are disposed on the inner part on the Ya axis, and piezoelectric element Y71 is disposed on the inner part on the Yb axis. To Y74 are arranged. Each of these piezoelectric elements bearing the capital letter X or Y is a piezoelectric element fixed to the surface of the inner connecting member (inner bridging portions 521, 531, 541, 551), and drives the main vibrator 510. Or a main detecting piezoelectric element for detecting the Coriolis force (displacement of the main vibrator 510) acting on the main vibrator 510.

  Using these 24 piezoelectric elements, a driving method in which the main vibrator 510 is simply vibrated in an arbitrary coordinate axis direction or circularly moved along an arbitrary coordinate plane, or an arbitrary action acting on the main vibrator 510 is used. Since the detection method for obtaining the Coriolis force in the coordinate axis direction is the same as the method described in §4-2 using the modification shown in FIG. 11, detailed description thereof is omitted here.

  On the other hand, the piezoelectric elements x51 to x54 are disposed on the outer portion on the X axis, the piezoelectric elements x61 to x64 are disposed on the outer portion on the Xa axis, and the piezoelectric element x71 is disposed on the outer portion on the Xb axis. To x74 are arranged. In addition, piezoelectric elements y51 to y54 are disposed on the outer portion on the Y axis, piezoelectric elements y61 to y64 are disposed on the outer portion on the Ya axis, and piezoelectric element y71 is disposed on the outer portion on the Yb axis. To y74 are arranged. Each of the piezoelectric elements bearing the lowercase alphabetic letter x or y is a piezoelectric element fixed to the surface of the outer connecting member (outer bridging portion 522, 532, 542, 552), and drives the sub vibrator 525. Or a sub-detecting piezoelectric element for detecting Coriolis force (displacement of the sub-vibrator 525) acting on the sub-vibrator 525.

  Using these 24 piezoelectric elements, the sub-vibrator 525 is simply oscillated in an arbitrary coordinate axis direction or circularly moved along an arbitrary coordinate plane, or an arbitrary action is applied to the sub-vibrator 525. Since the detection method for obtaining the Coriolis force in the coordinate axis direction is the same as the method described in §4-2 using the modification shown in FIG. 11, detailed description thereof is omitted here. However, it should be noted that the control is performed so that the driving direction of the main vibrator 510 and the driving direction of the sub vibrator 525 are always reversed.

  As described in §4-2, in the angular velocity sensor shown in FIG. 41, the main vibrator 510 is subjected to a predetermined periodic motion by using some of the 24 piezoelectric elements arranged on the inner connecting member. A method for detecting the Coriolis force acting on the main vibrator 510 using some of them, and a predetermined number for the sub vibrator 525 using some of the 24 piezoelectric elements arranged on the outer connecting member. There are various variations in the method of causing the periodic motion of the Coriolis to be detected and detecting the Coriolis force acting on the sub-vibrator 525 using some of them. By combining these variations, angular velocity detection around multiple axes becomes possible.

  However, when the main vibrator and the sub-vibrator are moved in the opposite directions, as shown in FIG. 39 and FIG. 40, a phenomenon occurs in which stress at a specific location increases. Sensitivity can be increased. From such a viewpoint, it is preferable to use the piezoelectric elements arranged at the points of interest Q1 to Q4 in FIG. 39 for detecting the Coriolis force Fx in the X-axis direction (the same applies to the Coriolis force Fy in the Y-axis direction). For detecting the Coriolis force Fz in the Z-axis direction, it is preferable to use piezoelectric elements arranged at the points of interest Q1 to Q4 in FIG.

  Specifically, for example, if the piezoelectric elements arranged on the X-axis and the Y-axis are used as detection piezoelectric elements, the piezoelectric elements x51, X52, For detecting the Coriolis force Fy in the Y-axis direction using X53, x54, it is preferable to use the piezoelectric elements y51, Y52, Y53, y54. For detecting the Coriolis force Fz in the Z-axis direction, for example, if a piezoelectric element arranged on the X-axis is used, it is preferable to use the piezoelectric elements X51, X52, X53, and X54, and on the Y-axis. If the piezoelectric element arranged at is used, it is preferable to use the piezoelectric elements Y51, Y52, Y53, Y54. Alternatively, a combination of piezoelectric elements X51, Y51, X54, and Y54 or a combination of piezoelectric elements X52, Y52, X53, and Y53 may be used for detecting the Coriolis force Fz in the Z-axis direction.

  In view of the phenomenon that the stress increases as described above, in order to vibrate the main vibrator and the sub-vibrator in the X-axis direction, it is preferable to use piezoelectric elements arranged at the points of interest Q1 to Q4 in FIG. In order to vibrate in the Z-axis direction, it is preferable to use piezoelectric elements arranged at the points of interest Q1 to Q4 in FIG. By making such a selection, each vibrator can be driven more efficiently.

<<< §10. Summary of technical ideas according to the present invention >>
The angular velocity sensor according to the present invention has been described with respect to some embodiments and modifications thereof. However, the present invention is not limited to these embodiments and modifications, and various other aspects are possible. Can be implemented. Here, technical ideas according to the present invention will be summarized.

  First, the most basic concept of the present invention is that a main vibrator, a sub-vibrator arranged adjacent to the main vibrator, a pedestal arranged adjacent to the sub-vibrator, and a main vibrator A basic structure having a first connecting member having flexibility for connecting the sub-vibrator and a second connecting member having flexibility for connecting the sub-vibrator and the pedestal; An apparatus housing that supports and fixes the pedestal and accommodates the main vibrator and the sub-vibrator in a suspended state, driving means that drives the main vibrator to perform periodic motion in the apparatus housing, and the main vibrator An angular velocity sensor is constituted by detecting means for detecting Coriolis force acting on the main vibrator and outputting it as a detected value of angular velocity about a predetermined axis in a state where periodic motion is performed. If such a configuration is adopted, the sub-vibrator is arranged on the vibration energy transmission path from the main vibrator to the pedestal, and the vibration energy leaking to the pedestal side due to the presence of this sub-vibrator. Some will be absorbed.

  In particular, in implementing the present invention, it is effective to provide a plurality of M sub-vibrators at positions surrounding the main vibrator. That is, the main vibrator is constituted by a central weight body, and the sub vibrator is constituted by a plurality of M weight bodies arranged in an annular closed region surrounding the side surface of the central weight body, The pedestal is arranged at a position further surrounding the annular closed region, and the inner connecting member is constituted by M inner bridge portions connecting the center weight body and the M weight bodies, respectively. The outer connecting member is constituted by M outer bridge portions that connect each of the M weight bodies and the pedestal.

  As a more preferred embodiment, an XYZ three-dimensional coordinate system having an origin O at the center position of the upper surface of the central weight body is defined, and M radiations extending around the origin O are defined on the XY plane of this coordinate system. The basic structure has an upper surface along the XY plane of this coordinate system, and one weight body constituting each sub-vibrator is disposed on each radiation, and each of the weights along each radiation. One set of the inner bridging portion and the outer bridging portion are arranged.

  Further, as a preferred embodiment, the inner bridge portion is connected to the upper end of the “facing surface with respect to the central weight body” of the weight body constituting the sub vibrator, and the “pedestal” of the weight body constituting the sub vibrator is formed. The outer bridging portion is connected to the upper end of the “opposite surface to”, and a groove portion extending in a direction perpendicular to the radiation on which the weight body is arranged is formed on the upper surface of the weight body constituting the sub vibrator. . The angular velocity sensor according to the first embodiment shown in FIGS. 5 and 6 corresponds to an example in which M = 4 is set in such a most preferred embodiment.

  In addition, it is also possible to constitute a single annular weight body by circularly connecting a plurality of M weight bodies constituting the sub-vibrator in order. The angular velocity sensor shown in FIG. 29 and FIG. 30 shown as the fourth embodiment is obtained by annularly connecting the four weight bodies in the angular velocity sensor according to the first embodiment shown in FIG. 5 and FIG. This corresponds to an example in which a single annular weight body 525 is configured.

  In the present invention, it is also possible to adopt a form in which the sub-vibrator is arranged so as to surround the main vibrator doubly. That is, the main vibrator is constituted by a central weight body, and the sub-vibrator is provided with a plurality of M inner weight bodies arranged in an inner annular closed region surrounding the side face of the central weight body, A plurality of M outer weights disposed in the outer annular closed region surrounding the annular closed region, the pedestal is disposed at a position further surrounding the outer annular closed region, and the inner connecting member is disposed at the center portion. M sets of inner bridging portions connecting the weight body and each of the M inner weight bodies, and the outer connection member is made up of M sets of connecting each of the M outer weight bodies and the pedestal. It is constituted by an outer cross-linked part. An intermediate connecting member constituted by a plurality of M intermediate bridge portions having flexibility to connect M inner weight bodies and M outer weight bodies in a one-to-one correspondence. It should be further provided.

  As a more preferred embodiment, an XYZ three-dimensional coordinate system having an origin O at the center position of the upper surface of the central weight body is defined, and M radiations extending around the origin O are defined on the XY plane of this coordinate system. When the basic structure has an upper surface along the XY plane of this coordinate system, one inner weight body and one outer weight body are arranged on each radiation, and along each radiation Each of the inner cross-linking portion, the intermediate cross-linking portion, and the outer cross-linking portion is arranged one by one.

  Further, as a preferred embodiment, the inner bridge is connected to the upper end of the “facing surface with respect to the central weight body” of the inner weight body, and the upper end of the “facing surface with respect to the outer weight body” of the inner weight body. One end of the intermediate bridge is connected, and the other end of the intermediate bridge is connected to the upper end of the “opposite surface to the inner weight” of the outer weight body, and the upper end of the “opposite surface to the pedestal” of the outer weight body An outer bridge is connected, and a groove extending in a direction perpendicular to the radiation on which the weight is disposed is formed on the upper surface of the inner weight, and the weight is disposed on the upper surface of the outer weight. A groove extending in a direction perpendicular to the radiation being formed is formed.

  The angular velocity sensor according to the second embodiment shown in FIGS. 19 and 20 corresponds to an example in which M = 4 is set in such a most preferred embodiment.

  A plurality of M outer weights constituting the sub-vibrator are configured by sequentially connecting a plurality of M inner weights constituting the sub-vibrator in a circular manner to form a single inner annular weight body. It is also possible to construct a single outer annular weight body by connecting the bodies in an annular fashion in order.

  Of course, in the present invention, it is possible to adopt a form in which the sub-vibrators are arranged so as to surround the main vibrator more than triple. In the embodiment shown so far, an example in which the sub-vibrator is arranged so as to surround the periphery of the main vibrator more than triple is not shown, but as a general rule, the circumference of the main vibrator is n-fold. When the sub-vibrators are arranged so as to surround, a total of n sub-vibrators are arranged on the vibration energy transmission path from the main vibrator to the pedestal, thereby further improving the effect of suppressing vibration leakage. Is possible.

  In the structure in which the main vibrator is supported using the bridging portion, if the sub-vibrator is arranged so as to surround the main vibrator n-folds, the main vibrator is constituted by a central weight body. In addition, a “first annular closed region” is defined at a position surrounding the side surface of the central weight body, and a “second annular closed region” is defined at a position surrounding the “first annular closed region”. ,..., And when the “n-th circular closed region” is defined at a position surrounding the “(n−1) -th circular closed region” (where n is an arbitrary natural number) ), The sub-vibrator is placed in a plurality of M “weights of the first circumference” arranged in the “circular closed area of the first circumference” and in the “annular closed area of the second circumference”. A plurality of M “second-round weights”, and a plurality of M “n-th weights” arranged in the “n-th circular closed region”. Body " Bayoi. Then, the pedestal is arranged at a position that further surrounds the “n-th annular closed region”, and the inner connection member is arranged with each of the central weight body and the M “first circumferential weight bodies”. And the outer connecting member is composed of M sets of outer bridging portions that connect each of the M “weights of the nth circumference” and the pedestal. It is possible to connect each of the M “weights of the i-th circumference” and the M “weights of the (i + 1) -th circumference” in a one-to-one correspondence. What is necessary is just to make it have further "the i-th intermediate connection member" (however, i = 1- (n-1)) comprised by the M bridge | crosslinking part of multiple M which has flexibility.

  As a more preferred embodiment, an XYZ three-dimensional coordinate system having an origin O at the center position of the upper surface of the central weight body is defined, and M radiations extending around the origin O are defined on the XY plane of this coordinate system. In this case, the basic structure has an upper surface along the XY plane of this coordinate system, and one weight body of each kth circumference (where k = 1 to n) is provided on each radiation. It is arranged that one set of inner cross-linking portions, one set of outer cross-linking portions, and (n-1) sets of intermediate cross-linking portions are arranged along each radiation.

  Furthermore, as a preferred embodiment, for each weight body constituting the sub-vibrator, connection to the other weight body is performed at the upper end of “an opposite surface to another weight body located on the inner peripheral side”. A bridging portion for connecting to the other weight body or pedestal is connected to the upper end of the “opposite surface to another weight body or pedestal positioned on the outer peripheral side”, A groove portion extending in a direction orthogonal to the radiation on which the weight body is arranged is formed on the upper surface of each weight body constituting the vibrator.

  In particular, when M = 4 is set, a structure for supporting the main vibrator from its four directions can be obtained. Specifically, when the XYZ three-dimensional coordinate system having the origin O at the center position of the upper surface of the central weight body is defined, the basic structure has an upper surface along the XY plane of this coordinate system, In the “k-th annular closed region”, the “k-th X-axis positive weight body” is arranged on the X-axis positive region, and “k-th circumference” is arranged on the Y-axis positive region. The “Y-axis positive weight body of the eye” is arranged, the “k-th X-axis negative weight body” is arranged on the negative region of the X-axis, and the “k-th circumference” is arranged on the negative region of the Y-axis. The Y-axis negative weight body of the eye ”is arranged (k = 1 to n). Then, one end is connected to the central weight body, the other end is connected to the “first-axis X-axis positive weight body”, and the X-axis positive inner side is disposed along the positive region of the X-axis. The bridging portion and one end are connected to the central weight body, the other end is connected to the “first-axis Y-axis positive weight body”, and the Y-axis positive electrode is disposed along the positive region of the Y-axis. A side inner bridge and one end connected to the central weight body, the other end connected to the “first-circumferential X-axis negative weight body”, and arranged along the negative region of the X-axis Axis negative side inner bridging part, one end is connected to the center part weight body, and the other end is connected to the “Y-axis negative side weight body in the first circumference”, arranged along the negative region of the Y axis Further, the inner connecting member is configured by the Y-axis negative-side inner bridge portion. Further, one end is connected to the pedestal, the other end is connected to the “n-th X-axis X-side positive weight body”, and the X-axis positive-side outer bridge portion disposed along the X-axis positive region; One end is connected to the pedestal, the other end is connected to the “n-th Y-axis positive-side weight body”, the Y-axis positive-side outer bridge portion disposed along the positive region of the Y-axis, and one end Connected to the pedestal, connected at the other end to the “nth circumference X-axis negative weight body”, arranged along the negative region of the X-axis, and one end at the pedestal The outer connection member is configured by a Y-axis negative-side outer bridging portion that is connected and connected at the other end to the “Y-axis negative-side weight body on the n-th circumference” and disposed along the negative region of the Y-axis. To be. Furthermore, one end is connected to the “X-axis positive weight body on the i-th circumference” and the other end is connected to the “X-axis positive weight body on the (i + 1) -th circumference”. The “i-th X-axis positive-side intermediate bridging portion” and one end are connected to the “i-th X-axis positive-side weight body”, and the other end is the “(i + 1) -th round”. "Y-axis positive-side weight bridge" connected to the "Y-axis positive-side weight body" and disposed along the positive region of the Y-axis, and one end of the "Y-th X-axis of the i-th circle" Connected to the “positive weight”, the other end connected to the “(i + 1) th circle X-axis negative weight”, and arranged along the negative region of the X axis `` Axis negative side intermediate bridge part '' and one end are connected to `` X-axis positive weight body on i-th circumference '', the other end is connected to `` Y-axis negative weight body on (i + 1) -th circumference '', “Y-axis Y-axis negative-side middle” arranged along the negative region of the Y-axis A bridge portion ", the intermediate connecting member" (where, i = 1~ (n-1)) "in the i-th revolution by is the as configured.

  As a more preferred embodiment, for each weight body constituting the sub-vibrator, a bridge for connecting to the other weight body at the upper end of “an opposite surface to another weight body located on the inner peripheral side” Are connected, and a bridging portion for connecting to another weight body or pedestal is connected to the upper end of “an opposite surface to another weight body or pedestal located on the outer peripheral side” to constitute a sub-vibrator A groove portion extending in a direction orthogonal to the coordinate axis where the weight body is arranged is formed on the upper surface of each weight body.

  As a more preferable embodiment, for each of the k-th circumference (where k = 1 to n), the X-axis positive weight body, the Y-axis positive weight body, the X-axis negative weight body, the Y-axis negative weight body The body is composed of weight bodies having the same shape and the same mass, and the arrangement of these four weight bodies is symmetric with respect to both the XZ plane and the YZ plane.

  Note that a plurality of M “kth circumference weights” constituting the sub-vibrator are sequentially connected in a circular manner to obtain a single “kth circumference weight” (where k = 1-n) can also be configured.

  On the other hand, instead of a structure that supports the main vibrator using the bridging portion, a structure that supports the main vibrator using a diaphragm structure may be employed. In such a structure, if the sub-vibrator is arranged so as to surround the main vibrator n-folds, the main vibrator is constituted by the central weight body, and the sub-vibrator is provided with the central weight. “Annular weight body of the first circumference” surrounding the weight body in a separated state, “Annular weight body of the second circumference” surrounding the “circular weight body of the first circumference” in a separated state, ,..., “N-th circumferential weight” surrounding the “n-th circumferential weight” in a separated state. The inner connecting member is arranged so as to surround the side surface of the central weight body, the inner part is connected to the central weight body, and the outer part is connected to the “annular weight body of the first circumference”. The outer connecting member is arranged so as to surround the “nth circumferential weight”, and the inner portion is connected to the “nth circumferential weight”. The outer portion is constituted by an outer plate-like structure connected to the pedestal, and the pedestal is constituted by a structure surrounding the outer plate-like structure. Further, it is constituted by a flexible intermediate plate-like structure connecting between the “annular weight body of the i-th circumference” and the “annular weight body of the (i + 1) -th circumference”. In addition, the “i-th circumferential intermediate connection member” may be disposed (where i = 1 to (n−1)).

  More preferably, for each annular weight body constituting the sub-vibrator, a plate for connecting to the other weight body at the upper end of the “opposite surface to another weight body located on the inner peripheral side” A plate-like structure for connecting to another weight body or pedestal is connected to the upper end of the "facing surface to another weight body or pedestal located on the outer peripheral side", A groove portion is formed on the upper surface of each annular weight body along the contour line of the upper surface of the annular weight body.

  More preferably, when an XYZ three-dimensional coordinate system having an origin O at the center position of the upper surface of the central weight body is defined, the basic structure has an upper surface along the XY plane of the coordinate system, and each annular weight The projection image of the weight body on the XY plane is formed in an annular shape with the origin O as the center.

It is a top view which shows an example of the basic structure of the conventional angular velocity sensor. It is the sectional side view which cut | disconnected the basic structure shown in FIG. 1 by the XZ plane. It is a top view which shows the basic structure of the angular velocity sensor which concerns on the 1st Embodiment of this invention. It is the sectional side view which cut | disconnected the basic structure shown in FIG. 3 by XZ plane. FIG. 4 is a top view showing a state in which a piezoelectric element is attached to the basic structure shown in FIG. 3 (hatching indicates a piezoelectric element, not a cross section). It is the sectional side view which cut | disconnected the basic structure with a piezoelectric element shown in FIG. 5 by the XZ plane. It is side sectional drawing which shows the structure and its characteristic of a general piezoelectric element. 7 is a graph showing the relationship between the AC voltage signal supplied to the piezoelectric element and the displacement of the main vibrator in the basic structure shown in FIGS. 5 and 6. FIG. It is a circuit diagram which shows an example of the circuit used for the angular velocity sensor which has the basic structure shown in FIG. 5 and FIG. It is a graph which shows the variation of the alternating voltage signal supplied to a piezoelectric element. It is a top view which shows the modification of the 1st Embodiment of this invention (a hatching shows a piezoelectric element and does not show a cross section). It is the fragmentary sectional side view which cut | disconnected the center part of the angular velocity sensor shown in FIG. 11 by XZ plane. It is a fragmentary sectional side view which shows the modification which changed the structure of the piezoelectric element shown in FIG. It is a fragmentary sectional side view which shows another modification which changed the structure of the piezoelectric element shown in FIG. It is a top view of the basic structure for demonstrating the modification shown in FIG. 13 and FIG. 14 (hatching is for demonstrating an area | region and does not show a cross section). It is a sectional side view which shows another modification of the 1st Embodiment of this invention. It is a top view which shows the basic structure of the angular velocity sensor which concerns on the 2nd Embodiment of this invention. It is the sectional side view which cut | disconnected the basic structure shown in FIG. 17 by XZ plane. It is a top view which shows the state which attached the piezoelectric element to the basic structure shown in FIG. 17 (a hatching shows a piezoelectric element and does not show a cross section). FIG. 20 is a side sectional view of the basic structure with a piezoelectric element shown in FIG. 19 cut along an XZ plane. It is a top view which shows the basic structure of the angular velocity sensor which concerns on the 3rd Embodiment of this invention. It is the sectional side view which cut | disconnected the basic structure shown in FIG. 21 by XZ plane. It is the plane sectional view which cut | disconnected the basic structure shown in FIG. 22 in the position of the cut surface 23-23. It is the plane sectional view which cut | disconnected the basic structure shown in FIG. 22 in the position of the cut surface 24-24. It is a top view which shows the state which attached the piezoelectric element to the basic structure shown in FIG. 21 (a hatching shows a piezoelectric element and does not show a cross section). It is the sectional side view which cut | disconnected the basic structure with a piezoelectric element shown in FIG. 25 by XZ plane. It is a top view which shows the basic structure of the angular velocity sensor which concerns on the 4th Embodiment of this invention. It is the sectional side view which cut | disconnected the basic structure shown in FIG. 27 by XZ plane. It is a top view which shows the state which attached the piezoelectric element to the basic structure shown in FIG. 27 (the hatching shows a piezoelectric element and does not show a cross section). FIG. 30 is a side sectional view of the basic structure with a piezoelectric element shown in FIG. 29 cut along an XZ plane. It is a sectional side view which shows the basic structure of the angular velocity sensor shown as a reference example. It is a sectional side view which shows the basic structure of the angular velocity sensor shown as another reference example. It is a perspective view which shows the simple model which has a main vibrator and a sub vibrator. It is a perspective view which shows an example of the drive state of each vibrator | oscillator in the model shown in FIG. It is a perspective view which shows another example of the drive state of each vibrator | oscillator in the model shown in FIG. It is a top view which shows the basic structure body with a piezoelectric element of the angular velocity sensor which concerns on the 5th Embodiment of this invention (a hatching shows a piezoelectric element and does not show a cross section). FIG. 37 is a side sectional view of the basic structure with a piezoelectric element shown in FIG. 36 cut along an XZ plane. It is a circuit diagram which shows an example of the circuit used for the angular velocity sensor which has a basic structure with a piezoelectric element shown in FIG. 36 and FIG. It is a sectional side view which shows an example of the drive state of the angular velocity sensor which has a basic structure with a piezoelectric element shown in FIG. FIG. 38 is a side sectional view showing another example of the driving state of the angular velocity sensor having the basic structure with piezoelectric elements shown in FIGS. 36 and 37. It is a top view which shows the modification of the 5th Embodiment of this invention (a hatching shows a piezoelectric element and does not show a cross section).

Explanation of symbols

21-24: Difference circuit 30, 35: Drive control circuit 31: AC signal source 40, 45: Angular velocity detection circuit 91: Main vibrator 92: Sub vibrator 93: Connection member 100: Basic structure 110 of conventional angular velocity sensor : Weight body (vibrator)
120 to 150: bridging section 160: pedestal 180: apparatus housing 200: basic structure 200 ′ of angular velocity sensor according to the first embodiment of the present invention: angular velocity sensor according to a modification of the first embodiment of the present invention Basic structure 200 ^* : Basic structure 210 of angular velocity sensor according to the reference example: Center weight (main vibrator)
221: X-axis positive side inner cross-linking part (inner connection member)
222: X-axis positive side outer cross-linking portion (outer connection member)
225, 225 ′: X-axis positive weight body (secondary vibrator)
225 ^* : U-shaped cross-linking portion 231: Y-axis positive inner cross-linking portion (inner connecting member)
232: Y-axis positive side outer cross-linking portion (outer connection member)
235: Y-axis positive weight body (secondary vibrator)
241: X-axis negative inner cross-linking part (inner connection member)
242: X-axis negative outer bridge (outer connecting member)
245, 245 ': X-axis negative weight body (secondary vibrator)
245 ^* : U-shaped bridge 251: Y-axis negative inner bridge (inner connection member)
252: Y-axis negative side outer cross-linking portion (outer connection member)
255: Y-axis negative weight body (secondary vibrator)
260: Base 280: Device housing 300: Basic structure 300 of angular velocity sensor according to the second embodiment of the present invention ^* : Basic structure 310 of angular velocity sensor according to reference example: Center weight body (main vibrator) )
321: X axis positive side inner cross-linking part (inner connection member)
322: X-axis positive-side intermediate bridge (intermediate connection member)
323: X-axis positive side outer cross-linking portion (outer connection member)
325: X-axis positive inner weight body (secondary vibrator)
325 ^* : U-shaped bridging portion 326: X-axis positive outer weight body (sub vibrator)
326 ^* : U-shaped bridge 331: Y-axis positive side inner bridge (inner connection member)
332: Y-axis positive side intermediate cross-linking part (intermediate connection member)
333: Y-axis positive side outer cross-linking portion (outer connection member)
335: Y axis positive inner weight body (secondary vibrator)
336: Y-axis positive outer weight body (secondary vibrator)
341: X-axis negative inner cross-linking part (inner connection member)
342: X-axis negative-side intermediate bridge (intermediate connection member)
343: X-axis negative side outer cross-linking portion (outer connection member)
345: X-axis negative inner weight body (secondary vibrator)
345 ^* : U-shaped bridge 346: X-axis negative outer weight body (secondary vibrator)
346 ^* : U-shaped bridge 341: Y-axis negative inner bridge (inner connection member)
342: Y-axis negative-side intermediate bridge (intermediate connection member)
343: Y axis negative side outer cross-linking portion (outer connection member)
345: Y-axis negative inner weight body (sub vibrator)
346: Y-axis negative outer weight body (secondary vibrator)
360: Pedestal 380: Device housing 400: Basic structure 410 of angular velocity sensor according to the third embodiment of the present invention: Center weight body (main vibrator)
421: inner plate-like structure (inner connection member)
422: Intermediate plate structure (intermediate connection member)
423: outside plate-like structure (outside connecting member)
425: Inner annular weight body (sub vibrator)
426: Outer annular weight body (sub vibrator)
460: Base 480: Device casing 500: Basic structure 510 of the angular velocity sensor according to the fourth embodiment of the present invention: Center weight body (main vibrator)
521: X axis positive side inner cross-linking part (inner connection member)
522: X-axis positive side outer cross-linking portion (outer connection member)
525: Annular weight (sub-vibrator)
531: Y-axis positive side inner cross-linking part (inner connection member)
532: Y-axis positive side outer cross-linking portion (outer connection member)
541: X-axis negative inner cross-linking part (inner connection member)
542: X-axis negative outer cross-linking portion (outer connecting member)
541: Y-axis negative inner cross-linking part (inner connection member)
542: Y-axis negative side outer cross-linking portion (outer connection member)
560: Base 580: Device casing A: Vibration amplitude value d: Phase difference / delay time EL: Lower electrode EL ′: Common conductive layer EU: Upper electrode Fx: Force in the X-axis direction Fz: Force G1 in the Z-axis direction -G4: Groove parts G1a-G4b: Groove parts G15, G20, G25, G30, G35: Annular groove part O: Origin of XYZ three-dimensional coordinate system P: Piezoelectric element body part P ': Common piezoelectric element body part Q1-Q4: Attention Point t: Time V: Voltage value Vp: Peak voltages W1 to W4, W11 to W42: Window portions X, Y, Z: XYZ coordinate axes Xa and Xb of the three-dimensional coordinate system are arranged beside the X axis, and the X axis Coordinate axes Ya, Yb parallel to the Y axis: coordinate axes X11 to X14 parallel to the Y axis: piezoelectric elements X21 to X24 disposed on the X axis: piezoelectric elements X31 to X31 disposed on the Xa axis X34: Piezoelectric elements X41 to X arranged on the Xb axis 4: Piezoelectric elements X51 to X54 arranged on the X axis: Piezoelectric elements X61 to X64 arranged on the X axis: Piezoelectric elements X71 to X74 arranged on the Xa axis: Piezoelectric elements arranged on the Xb axis x51 to x54: Piezoelectric elements arranged on the X axis x61 to x64: Piezoelectric elements arranged on the Xa axis x71 to x74: Piezoelectric elements Y11 to Y14 arranged on the Xb axis: arranged on the Y axis Piezoelectric elements Y21 to Y24: Piezoelectric elements Y31 to Y34 arranged on the Ya axis: Piezoelectric elements Y41 to Y44 arranged on the Yb axis: Piezoelectric elements Y51 to Y54 arranged on the Y axis: Arranged on the Y axis Piezoelectric elements Y61 to Y64: Piezoelectric elements Y71 to Y74 arranged on the Ya axis: Piezoelectric elements y51 to y54 arranged on the Yb axis: Piezoelectric elements y61 to y64 arranged on the Y axis: On the Ya axis set on Piezoelectric element Y71～y74: a piezoelectric element arranged on the Yb axis .phi.1, .phi.2: AC voltage signal .omega.x, .omega.y: angular velocity

Claims (7)

A main vibrator, a sub-vibrator disposed adjacent to the main vibrator, a pedestal disposed adjacent to the sub-vibrator, and a flexibility connecting the main vibrator and the sub-vibrator A basic structure having an inner connecting member having a property and a flexible outer connecting member for connecting the sub-vibrator and the pedestal;
An apparatus housing that supports and fixes the pedestal and accommodates the main vibrator and the sub vibrator in a suspended state;
Drive means for driving the main oscillator to perform periodic motion in the apparatus housing;
Detecting means for detecting Coriolis force acting on the main vibrator in a state where the main vibrator performs the periodic motion, and outputting the detected value as a detected value of angular velocity around a predetermined axis;
With
The main vibrator is constituted by a central weight body, and the sub vibrator is constituted by a plurality of M weight bodies arranged in an annular closed region surrounding a side surface of the central weight body, The pedestal is disposed at a position that further surrounds the annular closed region, and the inner connecting member is configured by M sets of inner bridging portions that connect the central weight body and the M weight bodies, respectively. The outer connecting member is constituted by M sets of outer bridging portions that connect each of the M weight bodies and the pedestal,
When an XYZ three-dimensional coordinate system having an origin O at the center position of the upper surface of the central weight body is defined, and M radiations extending around the origin O are defined on the XY plane of the coordinate system, The basic structure has an upper surface along the XY plane of the coordinate system, and one weight body that constitutes the sub-vibrator is disposed on each of the M radiations, and each of the weights along each radiation. The inner bridge part and the outer bridge part are arranged one by one,
The inner bridge portion is connected to the upper end of the “facing surface with respect to the central weight body” of the weight body constituting the sub vibrator, and the “facing surface with respect to the pedestal” of the weight body constituting the sub vibrator. The outer bridge portion is connected to the upper end of the sub-vibrator, and a groove portion extending in a direction perpendicular to the radiation on which the weight body is disposed is formed on the upper surface of the weight body constituting the sub-vibrator,
The driving means drives the main vibrator to perform a periodic motion in the apparatus housing, and causes the sub-vibrator to move in a direction opposite to the movement of the main vibrator in the apparatus housing. The main vibrator and the sub-vibrator are caused to vibrate in a direction parallel to a predetermined common vibration axis with the same amplitude and the same frequency, respectively, and the movement direction of the main vibrator and the movement of the sub-vibrator An angular velocity sensor that is driven so that the direction is always in the opposite direction, and the absolute value of the motion speed of the main vibrator is equal to the absolute value of the motion speed of the sub-vibrator. A main vibrator, a sub-vibrator disposed adjacent to the main vibrator, a pedestal disposed adjacent to the sub-vibrator, and a flexibility connecting the main vibrator and the sub-vibrator A basic structure having an inner connecting member having a property and a flexible outer connecting member for connecting the sub-vibrator and the pedestal;
  An apparatus housing that supports and fixes the pedestal and accommodates the main vibrator and the sub vibrator in a suspended state;
  Drive means for driving the main oscillator to perform periodic motion in the apparatus housing;
  Detecting means for detecting Coriolis force acting on the main vibrator in a state where the main vibrator performs the periodic motion, and outputting the detected value as a detected value of angular velocity around a predetermined axis;
  With
  The main vibrator is constituted by a central weight body, and the sub vibrator is constituted by a plurality of M weight bodies arranged in an annular closed region surrounding a side surface of the central weight body, The pedestal is disposed at a position that further surrounds the annular closed region, and the inner connecting member is configured by M sets of inner bridging portions that connect the central weight body and the M weight bodies, respectively. The outer connecting member is constituted by M sets of outer bridging portions that connect each of the M weight bodies and the pedestal,
  When an XYZ three-dimensional coordinate system having an origin O at the center position of the upper surface of the central weight body is defined, and M radiations extending around the origin O are defined on the XY plane of the coordinate system, The basic structure has an upper surface along the XY plane of the coordinate system, and one weight body that constitutes the sub-vibrator is disposed on each of the M radiations, and each of the weights along each radiation. The inner bridge part and the outer bridge part are arranged one by one,
  The inner bridge portion is connected to the upper end of the “facing surface with respect to the central weight body” of the weight body constituting the sub vibrator, and the “facing surface with respect to the pedestal” of the weight body constituting the sub vibrator. The outer bridge portion is connected to the upper end of the sub-vibrator, and a groove portion extending in a direction perpendicular to the radiation on which the weight body is disposed is formed on the upper surface of the weight body constituting the sub-vibrator,
  The driving means drives the main vibrator to perform a periodic motion in the apparatus housing, and causes the sub-vibrator to move in a direction opposite to the movement of the main vibrator in the apparatus housing. The main oscillator and the sub-oscillator are caused to move circularly so as to rotate in the opposite directions at the same period on a specific motion plane parallel to a predetermined common reference plane. The direction of motion and the direction of motion of the sub-vibrator are always opposite to each other, and the absolute value of the motion speed of the main vibrator and the absolute value of the speed of motion of the sub-vibrator are equal. Angular velocity sensor. The angular velocity sensor according to claim 1 or 2 ,
An angular velocity sensor characterized in that a single annular weight body is formed by annularly connecting a plurality of M weight bodies constituting a sub-vibrator in order. The angular velocity sensor according to any one of claims 1 to 3 ,
The driving means has a driving piezoelectric element fixed to the surface of the inner connecting member, and a drive control circuit for supplying an AC driving signal to the driving piezoelectric element,
A detecting means for detecting a piezoelectric element fixed on the surface of the inner connecting member; and an angular velocity detecting circuit for detecting a charge generated in the detecting piezoelectric element and outputting a detected value of the angular velocity based on the detection result. An angular velocity sensor comprising: The angular velocity sensor according to any one of claims 1 to 3 ,
The driving means includes a driving displacement electrode provided on the surface of the main vibrator, a driving fixing electrode opposed to the driving displacement electrode and fixed to the apparatus housing, and an alternating current between the pair of driving electrodes. A drive control circuit for supplying a drive signal,
The detection means includes a detection displacement electrode provided on the surface of the main vibrator, a detection fixed electrode facing the detection displacement electrode and fixed to the apparatus housing, and a static between the pair of detection electrodes. An angular velocity sensor comprising: an angular velocity detection circuit that detects a capacitance and outputs a detection value of the angular velocity based on a detection result. The angular velocity sensor according to any one of claims 1 to 3 ,
The driving means includes a main driving piezoelectric element fixed to the surface of the inner connecting member, a sub driving piezoelectric element fixed to the surface of the outer connecting member, the main driving piezoelectric element, and the sub driving piezoelectric element. A drive control circuit for supplying an AC drive signal,
A detecting means for detecting a piezoelectric element fixed on the surface of the inner connecting member; and an angular velocity detecting circuit for detecting a charge generated in the detecting piezoelectric element and outputting a detected value of the angular velocity based on the detection result. An angular velocity sensor comprising: In the angular velocity sensor according to any one of claims 1 to 6 ,
An angular velocity sensor characterized in that the mass of the main vibrator and the mass of the sub-vibrator are equal.