JPH0748048B2 - Vibrating gyro - Google Patents

Description

The present invention relates to a vibrating gyro that detects Coriolis force for the purpose of detecting angular velocity.

[Conventional technology]

Conventionally, as this type of vibration gyro, for example, there is a piezoelectric type gyro as shown in FIG. 7, which is provided on each of the surfaces of the base 1 orthogonal to the Y axis in the three-dimensional coordinate system. , A bimorph oscillator made of a piezoelectric material, a unimorph oscillator, and other drive oscillators 2 are fixed in a tuning fork shape so that they protrude in the Z-axis direction, and the free ends of the respective drive oscillators 2 are also Further, the detection vibrator 3 made of a piezoelectric material is fixed by fixing each wide surface in a direction orthogonal to that of the drive vibrator 2.

In using such a vibration gyro, first, an AC voltage is applied to the drive vibrator 2 to cause the drive vibrator 2 to vibrate symmetrically in the direction of the solid arrow (Y-axis direction). In addition to the method of applying an AC voltage to each of the drive vibrators 2, as a method of producing such symmetrical vibration, an AC voltage is applied to only one drive vibrator 2 and the other drive vibrator 2 is applied.
Is used as a vibration monitor to control the vibration state,
There is a method of stabilizing the vibration by this. Each of these is of a type in which the drive vibrator 2 is vibrated in a resonance state to increase the vibration amplitude in order to increase the Coriolis force described later.

Then, under the vibrating state of the drive vibrator 2, by rotating the entire vibrating gyro at an angular velocity ω about the Z axis,
Set it on the sensing oscillator 3 in the direction of the broken arrow in the figure (X-axis direction).
To generate a Coriolis force Fc that acts so as to bend depending on the magnitude of the angular velocity ω. As a result, a voltage is generated between the electrodes provided on the detection vibrator 3.

Since the generated voltage is proportional to the Coriolis force Fc, the magnitude of the angular velocity ω can be detected by measuring the voltage.

Incidentally, in general, a device for increasing the operating efficiency in a resonance state by supporting the entire device as described above by the supporting member 4 is made.

[Problems to be Solved by the Invention]

However, in such a conventional technique, since the detection oscillator 3 is connected to the tip of the drive oscillator 2, the size of the device is increased and an AC voltage is supplied to the drive oscillator 2. There is a drawback that the wiring, the wiring for taking out the signal voltage from the detection vibrator 3 and the like are complicated. In particular, the wiring for the detection vibrator 3 has a great deal of difficulty in routing the wire rod.

That is, the detection oscillator 3 is always about several μm to 100 μm.
It is placed under a vibration amplitude of about μm, and the mass and elastic modulus of the wire rod for extracting the signal voltage, as well as the deformation state and the like, have a large influence mainly on the vibration of the drive vibrator 2 and the detection sensitivity. Since the wire rod adheres to the side surface 2 ′ of the drive vibrator 2 and extends to the vicinity of the base 1 where vibration is small, and pulls out from there to a predetermined connection terminal. The connection terminal is extended to a position near the detection vibrator 3 to shorten the length of the wire rod to reduce the influence of the wire rod.

However, according to such a method, it is inevitable to significantly reduce the manufacturing work efficiency of the vibration gyro.

On the other hand, when the wide surface of the drive vibrator 2 and the wide surface of the detection vibrator 3 are not exactly orthogonal to each other,
A vibration component in the Y-axis direction leaks into the detection signal from the detection vibrator 3, and the detection accuracy itself decreases. By the way, as shown in the figure, under the structure in which the end face of the drive vibrator 2 and the end face of the detection vibrator 3 are directly connected, it is possible to obtain high connection accuracy by simply fixing them with an adhesive. Nor.

Therefore, there has been proposed a method of connecting the drive vibrator 2 and the detection vibrator 3 via a connecting member 5 as shown in FIG. According to the method of using the connecting member 5, the respective end portions of the driving vibrator 2 and the detecting vibrator 3 are provided on the surfaces of the connecting member 5 which are formed in the connecting member 5 and are oriented in directions orthogonal to each other. By bonding via the electrodes, the drive vibrator 2 and the detection vibrator 3 can be connected relatively easily with a high squareness.

However, even in this case, since the driving oscillator adhering surface and the detecting oscillator adhering surface are oriented in directions orthogonal to each other, in order to perform the adhering at the same time, the driving oscillator 2 and the detecting oscillator are attached. Each of the three must be accurately positioned and held on the connecting member 5 under a predetermined relative relationship until the adhesive is hardened, and a jig structure required for that purpose must be complicated. It As a result, the jig becomes large and the workability deteriorates. Further, if such a bonding work is performed in two steps, the number of work steps will be significantly increased.

The present invention advantageously solves the above-mentioned problems of the prior art, and realizes sufficient miniaturization of the device, routing of various wirings, and highly accurate assembly of the detection means and the driving means. It is an object of the present invention to provide a vibrating gyro, which can be greatly improved in productivity by making it extremely easy and has excellent detection sensitivity.

[Means for Solving the Problems]

A vibrating gyroscope according to the present invention is a vibrating gyroscope in which a first arm member and a second arm member are protruded and fixed to respective surfaces orthogonal to a Y axis of a base in a three-dimensional coordinate system. In the Y-axis direction, each of the arm members having the major axis in the Z-axis direction has two surfaces orthogonal to the X axis, two surfaces orthogonal to the Y axis, and two surfaces orthogonal to the Z axis. Of the polarized hexahedral piezoelectric material,
A first vibrator in which driving electrodes are provided on the respective surfaces orthogonal to the Y axis without being offset in the X axis direction; and a rectangular parallelepiped shape similar to that of the piezoelectric material is formed and polarized in the Z axis direction. A second vibrator, in which at least one detection electrode is arranged on one of the surfaces in the other piezoelectric material orthogonal to the Y axis with one side in the X axis direction offset, Each surface orthogonal to the
The electrodes, which are offset in the axial direction, are joined to each other so that they are located on the outside, and the first and second biased members are respectively biased to the free ends of the first and second arm members in the Y-axis direction. The oscillating mass is provided.

Here, preferably, the first and second vibrators are bonded to each other via a conductive shim, and preferably, the connection terminal of the detection electrode provided on the second vibrator is connected to the Y-axis of the piezoelectric material. It is arranged on each surface orthogonal to.

[Action]

The operation of the vibration gyro will be described below with reference to the schematic diagram shown in FIG.

In the figure, when the device is rotated around the Z axis at an angular velocity ω while vibrating the free end of the arm member 6 at a velocity V, a Coriolis force Fc is generated in the X axis direction. The magnitude is expressed as Fc = 2mVω. According to this, even if the vibration velocity V and the angular velocity ω are the same, the Coriolis force Fc generated increases as the mass m increases.

Therefore, in the present invention, by providing the vibrating mass 7 as shown at the free end of the arm member 6, the generated Coriolis force itself is sufficiently increased, and the vibrating mass 7 is moved in the Y-axis direction. By locating it in an eccentric position, the moment arm of the torsion moment M acting on the arm member 6 can be made sufficiently large.

Thus, according to such a vibration gyro, the angular velocity ω
It is possible to detect with high sensitivity the torsional moment M, which is caused by the above, and the Coriolis force Fc.

Further, according to the present invention, the first vibrator functioning as the driving unit and the second vibrator functioning as the detecting unit are surface-bonded to each other to form the arm member. In addition to being simple and quick, the device can be made compact enough and signals can be supplied and taken out in the vicinity of the base so that the wire can be run for a long time. It is possible to eliminate all inconveniences caused by.

In addition, here, when the first and second vibrators are joined via a conductive shim, the mechanical strength of the arm member can be increased, and the mutual connection of these both vibrators and those It is possible to facilitate the connection to an external circuit. Among them, the ease of electrical connection is that the connection terminal of the detection electrode provided on the second vibrator is
It becomes more prominent when they are arranged on the respective planes orthogonal to the axis, and by any of them, it is possible to advantageously eliminate the difficulty of routing the wire rod.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention.

In the figure, 16 and 17 respectively indicate the first and second arm members, and these arm members 16 and 17 are in the three-dimensional coordinate system
One end of each of 8 is fixed to each surface orthogonal to the Y-axis, and the projection is provided in the Z-axis direction.

Here, each of the arm members 16 and 17 will be described with reference to FIGS. 2 to 5 by taking the first arm member 16 as an example. At least a first vibrator 11 and a second vibrator 14 are provided. It is composed of. That is, the first oscillator 11 has two surfaces x ₁ and x ₂ orthogonal to the X axis, two surfaces y ₁ and y ₂ orthogonal to the Y axis, and two surfaces z ₁ and z ₂ orthogonal to the Z axis. The rectangular hexahedron-shaped piezoelectric material 8 is polarized in the Y-axis direction, and driving electrodes are respectively formed on the surfaces y ₁ and y ₂ of the piezoelectric material 8 orthogonal to the Y-axis.
By providing 9,10, they are configured to function as a drive means.

Further, as shown in FIG. 3, the second vibrator 14 polarizes the piezoelectric material 8 having the same shape and dimensions as the first vibrator 11 shown in FIG. 2 in the Z-axis direction, and On the surfaces y ₁ and y ₂ which are orthogonal to the Y axis, there are provided detection electrodes 12 and 13 which are respectively arranged near the x ₂ plane which extends in the Z axis (long axis direction) and intersects the X axis. Each of them is provided so that they function as a detecting means.

That is, at least one of the detection electrodes 12 and 13 is arranged so as to be offset to either side in the X-axis direction.

And, such first and second vibrators 11 and 14 are
It is also preferred, fourth through the conductive shim 15 made of sheet metal and other such as shown in FIG., The surface y ₂ of the first vibrator 11 and the surface y ₁ of the second oscillator 14, As shown in FIG. 5, the detection electrodes 13 which are offset in the X-axis direction are made to face each other so as to be located at least on the outer side, and pressure-bonded by a conductive adhesive for electrical connection. Such a first arm member 16 is configured. In addition to the purpose of electrical connection, this pressure bonding functions to improve mechanical strength and facilitate mutual connection of the electrodes 10 and 12 and connection to an external circuit.

With each member thus configured, as shown in a perspective view in FIG. 1, the first and second arm members 16 and 17 are provided on the respective surfaces of the base 18 that are orthogonal to the Y axis. The second vibrators 14 are opposed to each other and pressure-bonded, and further, the free ends of the arm members 16 and 17 are provided with the first and second vibrating masses 19 and 20, respectively. In the figure, they are mounted so as to be biased in the Y-axis direction and biased in the direction in which they are separated from each other.

Here, these oscillating masses 19, 20 are, as described above,
In order to increase the generated Coriolis force Fc, and the deviation of the oscillating masses 19 and 20 in the Y-axis direction, as described above, the Coriolis force is applied to the respective arm members 16 and 17. Each acts to increase the torsional moment caused by Fc.

The electrode configuration of the second vibrator 14 shown in FIG.
The configuration is not limited to this, but may be configured as shown in FIG. 6, for example. That is, the rectangular parallelepiped-shaped piezoelectric material 8 is polarized in the Z-axis direction, and one surface y ₁ thereof orthogonal to the Y-axis has the detection electrode 12 attached to substantially the entire surface thereof while the other surface is attached. The y ₂ may be provided only in the portion near the X-axis intersecting surface. Furthermore, in a part of the surfaces y ₁ and y ₂ of each transducer 14 illustrated in FIGS. 3 and 6 where the detection electrodes are not formed, in a form separated from the adjacent electrodes already formed, In particular, a new electrode may be added near the x ₁ side, and there is no difference in the operating effect between them.

In each vibrating gyro as described above,
The lead wire 21 connected to the lower end of the conductive shim 15 is grounded, and the lead wire 22 connected to the lower end of the drive electrode 9 provided on the first vibrator 11 of the first arm member 16 is grounded. When an AC voltage is applied via the first arm member 16, the first arm member 16 vibrates in the Y-axis direction, and at the resonance point, the first arm member 16 and the second arm member 17 vibrate symmetrically with a large amplitude. Therefore, when the device is rotated around the Z axis at an angular velocity ω while maintaining the vibration state of the arm members 16 and 17, the respective arm members 1
Torsional moments due to Coriolis force act on 6 and 17, and torsional shear stress acts on the second vibrator 14 as a component of the arm members 16 and 17 to cause detection electrode 1
Between 2 and 13, torsional shear stress, and eventually electrical displacement (voltage) according to Coriolis force is generated.

Therefore, for example, the Coriolis force can be detected by outputting an electric signal from the detection electrode 13 via the lead wire 23. In addition, here, it is possible to stabilize the vibration by using the first vibrator of the second arm member 17 as a monitor of the vibration state.
An electric signal resulting from the Coriolis force can also be taken out from the second vibrator of the second arm member 17.

Although the present invention has been described above based on the illustrated example, the first and second oscillators of the respective arm members may have a relative positional relationship opposite to that of the illustrated example, and the respective vibration masses are , It is also possible to bias them in the direction in which they are close to each other.

〔The invention's effect〕

Thus, according to the present invention, by assembling the arm member by surface-bonding the first vibrator functioning as the driving unit and the second vibrator functioning as the detecting unit, the device can be assembled with high accuracy. The device can be made extremely small, and the device can be sufficiently miniaturized, so that the application field is expanded. Moreover, by joining the wide-width vibrators to each other and then cutting them into a predetermined width, a large amount of arm members can be efficiently produced, and the variation in the performance of each arm member is effectively removed. Therefore, it becomes possible to supply a well-balanced vibrating gyro inexpensively and in large quantities.

Further, since the electrodes of the second vibrator may be formed on a wide surface orthogonal to the Y axis, like the first vibrator, work such as etching is easy, and lead wires are generally connected. It also has the effect of being able to do the same as bimorphs.

Further, in the device of the present invention, since all of the signal supply and signal extraction can be performed in the vicinity of the base,
It is possible to almost completely eliminate the inconvenience caused by the wiring of the wire.

In this device, the vibration mass is provided at the free end of the arm member, and the vibration mass is positioned so as to be offset in the Y-axis direction, whereby the detection sensitivity of the Coriolis force can be greatly improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIGS. 2 to 5 are perspective views illustrating constituent parts of arm members and arm members made of them, respectively, and FIG. Particularly, a perspective view showing an embodiment of the second vibrator, FIG. 7 is a perspective view showing a conventional example, FIG. 8 is a perspective view showing a conventional connecting member, and FIG. 9 is a view showing the device of the present invention. It is a schematic diagram for demonstrating an effect. 8 ... Piezoelectric material, 9,10 ... driving electrode, 11 ... first vibrator, 12,13 ... detecting electrode, 14 ... second vibrator, 15
...... Conductive shim, 16 …… First arm member, 17 …… Second arm member, 18 …… Base, 19,20 …… Vibration mass, 21,22,23 ……
Lead.

Claims (1)

[Claims] 1. A vibrating gyroscope in which a first arm member and a second arm member are fixed by projecting in the Z-axis direction on respective surfaces orthogonal to the Y-axis of a base in a three-dimensional coordinate system. Each arm member having the major axis in the Z-axis direction has two surfaces orthogonal to the X axis, two surfaces orthogonal to the Y axis, and two surfaces orthogonal to the Z axis, and is polarized in the Y axis direction. Of a rectangular hexahedral piezoelectric material,
A first vibrator in which driving electrodes are provided on the respective surfaces orthogonal to the Y axis without being offset in the X axis direction; and a rectangular parallelepiped shape similar to that of the piezoelectric material is formed and polarized in the Z axis direction. A second vibrator in which at least one sensing electrode is provided on one of the surfaces of the other piezoelectric material orthogonal to the Y axis and is offset to one side in the X axis direction. Each surface orthogonal to the
The electrodes, which are offset in the axial direction, are joined to each other so that they are located on the outside, and the first and second biased members are respectively biased to the free ends of the first and second arm members in the Y-axis direction. A vibrating gyroscope equipped with a vibrating mass.