JP4529286B2 - Angular velocity sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an angular velocity sensor used for attitude control of a moving body such as an aircraft or a vehicle, a navigation system, or the like.
[0002]
[Prior art]
As a conventional angular velocity sensor of this kind, one disclosed in Japanese Patent Laid-Open No. 8-1701717 is known.
[0003]
A conventional angular velocity sensor will be described below with reference to the drawings.
[0004]
FIG. 12 is a perspective view showing a state in which a tuning fork is fixed to a base in a conventional angular velocity sensor, and FIG. 13 is a side sectional view of the angular velocity sensor.
[0005]
12 and 13, reference numeral 1 denotes a columnar tuning fork, which includes a pair of column portions 2 and a connection portion 3 that connects the ends of the column portions 2. A driving piezoelectric element 4 is provided on each outer surface of the pair of column portions 2 of the tuning fork 1, and a reference piezoelectric element 5 is provided on the same side as the side surface on which the driving piezoelectric element 4 is provided. Further, a pair of detection piezoelectric elements 6 are provided on a side surface different from the side surface on which the driving piezoelectric element 4 and the reference piezoelectric element 5 are provided in the tuning fork 1. 7 is a metal support member that supports the base of the connecting portion 3 of the tuning fork 1. Reference numeral 8 denotes a metal base, and the lower surface of the support member 7 is fixed to the upper surface, and a plurality of terminal insertion holes 9 are provided in the base 8, and the terminal 10 is connected to the insulator 11 in the terminal insertion hole 9. Further, the terminal 10 is electrically connected to the driving piezoelectric element 4, the reference piezoelectric element 5, and the detecting piezoelectric element 6 of the tuning fork 1. A circuit board 12 is provided below the base 8 and is electrically connected to a lead wire 13 electrically connected to the terminal 10 of the base 8 by soldering, and the detection piezoelectric element 6 of the tuning fork 1. The electronic component 14 for processing the output signal generated by the angular velocity is provided on the upper surface. Reference numeral 15 denotes a support, which supports the base 8 and the circuit board 12 by stud bolts 16. A metal cover 17 accommodates the tuning fork 1, the base 8 and the circuit board 12 inside and covers the support base 15.
[0006]
Next, the operation of the conventional angular velocity sensor configured as described above will be described.
[0007]
By applying an AC voltage to the driving piezoelectric element 4 of the tuning fork 1, the tuning fork 1 bends and vibrates at a speed V in the driving direction at a natural frequency in the driving direction. In this state, when the tuning fork 1 rotates about the central axis of the tuning fork 1 at an angular velocity ω, a Coriolis force of F = 2 mV · ω is generated in the pair of column portions 2 of the tuning fork 1. The electric charge generated in the detection piezoelectric element 6 due to the Coriolis force is amplified by the electronic component 14 of the circuit board 12, and the angular velocity is detected by measuring the output voltage with an external computer.
[0008]
[Problems to be solved by the invention]
However, in the above conventional configuration, as shown in FIG. 13, the base 8 and the circuit board 12 are connected to the support base 15 with the stat bolt 16, so that vibration enters from the outside via the stat bolt 16. As a result, since this vibration is applied to the tuning fork 1, electric charges may be generated in the detection piezoelectric element 6 of the tuning fork 1 even when the angular velocity is not applied to the angular velocity sensor, and as a result, the output characteristics of the angular velocity sensor. Has the problem of deterioration.
[0009]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described conventional problems and to provide an angular velocity sensor with improved output characteristics in which vibration is not transmitted to the tuning fork even when vibration is applied from the outside in the state where the angular velocity is not added to the angular velocity sensor. To do.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an angular velocity sensor according to the present invention includes a tuning fork that outputs a signal in accordance with an angular velocity, a first base that fixes a part of the tuning fork to an upper surface, and an adhesive that is fixed to the first base. A first cover that covers the tuning fork, a first rubber body that comes into contact with the upper surface of the first cover, a second rubber body that comes into contact with the lower surface of the first base, A support plate whose upper surface is in contact with the lower surface of the second rubber body, a second base whose upper surface is in contact with the support plate, the second base, a tuning fork, a first base, and a first base; A cover, a first rubber body, a second rubber body, and a bottomed cylindrical second cover that covers the support plate, and at least four wall portions are provided so as to protrude upward from the upper surface of the support plate , this wall portion, thereby positioning and fixing the four sides of the second rubber body, small in the support plate By providing a contact portion at the upper end of at least two wall portions, contacting the contact portion with the lower surface of the first rubber body, and covering the first cover with the second cover, In this configuration, the support plate is pressed in the direction of the second base via a rubber body. According to this configuration, even if vibration is applied from the outside in a state where the angular velocity is not added to the angular velocity sensor, the vibration is Therefore, it is possible to provide an angular velocity sensor with improved output characteristics that is less likely to be added.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 of the present invention is a tuning fork that outputs a signal according to an angular velocity, a first base that fixes a part of the tuning fork to the upper surface, and a first base that is fixed to the first base. And a first cover that covers the tuning fork, a first rubber body that contacts the upper surface of the first cover, a second rubber body that contacts the lower surface of the first base, A support plate whose upper surface is in contact with the lower surface of the rubber body, a second base whose upper surface is in contact with the support plate, the second base and tuning fork, a first base, a first cover, A bottomed cylindrical second cover that covers the first rubber body, the second rubber body, and the support plate, and at least four wall portions are provided so as to protrude upward from the upper surface of the support plate. Since the four side surfaces of the second rubber body are positioned and fixed by the wall portion, the second rubber body is caused by lateral vibration. Four walls even attempts to move becomes possible to suppress the movement, since the tuning fork against the lateral vibration is eliminated that arises to move, together with the characteristics are improved with respect to vibration from the outside, the support By providing an abutting portion at the upper end of at least two wall portions of the plate, contacting the abutting portion with the lower surface of the first rubber body, and covering the first rubber body with the second cover, Since the support plate is pressed in the direction of the second base via the first rubber body, even if a large impact force in the vertical direction is applied to the angular velocity sensor, the support plate is moved by the inertial force to the second base. This means that there will be no separation from the top surface of the table, and no extra external force other than the Coriolis force generated by the angular velocity will be applied to the tuning fork. Those having an effect of stable.
[0012]
Hereinafter, an angular velocity sensor according to an embodiment of the present invention will be described with reference to the drawings.
[0013]
1 is an exploded perspective view of an angular velocity sensor according to an embodiment of the present invention, FIG. 2 is a side sectional view and a side view of the angular velocity sensor, FIG. 3 is a perspective view of a tuning fork in the angular velocity sensor, and FIG. FIG. 5 is a perspective view of the second rubber body in the angular velocity sensor, FIG. 6 is a perspective view of the first rubber body in the angular velocity sensor, and FIG. 7 is the perspective view of the angular velocity sensor. FIG. 8 is a perspective view of the circuit board, FIG. 8 is a top view showing a state where the flexible wiring board is soldered to the circuit board in the same angular velocity sensor, and FIG. 9 is a perspective view of the support plate in the angular velocity sensor.
[0014]
1 to 9, reference numeral 21 denotes a first vibrating body in which single crystal quartz thin plates having different crystal axes are bonded to each other. As shown in FIG. 3, a first drive electrode 22 is provided on the surface. As shown in FIG. 4, the second drive electrode 23 is provided on the back surface, the first detection electrode 24 made of gold is provided on the outer side surface, and the second detection electrode 25 made of gold is provided on the inner side surface. ing. Reference numeral 26 denotes a second vibrating body in which single crystal quartz thin plates having different crystal axes are bonded to each other. A fourth driving electrode 27 made of gold is provided on the front surface, and a third driving electrode 28 is provided on the rear surface. The third detection electrode 29 is provided on the outer side surface, and the fourth detection electrode 30 is provided on the inner side surface. Reference numeral 31 denotes a connection portion made of quartz, which connects one end of the first vibrating body 21 and the second vibrating body 26. The first vibrating body 21, the second vibrating body 26 and the connecting portion 31 constitute a tuning fork 31 a. Reference numeral 32 denotes a first base made of metal, which secures the connecting portion 31 in the tuning fork 31a, and is provided with six terminal insertion holes 33. The terminal insertion holes 33 have first drive electrodes 22, The second drive electrode 23, the third drive electrode 28, the fourth drive electrode 27, the first detection electrode 24, the second detection electrode 25, the third detection electrode 29, and the fourth detection electrode 30 are electrically connected to each other. Six terminals 34 to be connected to each other are inserted. A first metal cover 35 is fixed to the outer peripheral portion of the first base 32, and a tuning fork 31 a is housed inside the first base 32 and the cover 35. At this time, the fixing portions of the first cover 35 and the first base 32 are in close contact so that the inside of the first base 32 and the first cover 35 is in a vacuum state. Reference numeral 36 denotes a second rubber body having an upper surface abutting against the lower surface of the first base 32 and, as shown in FIG. 5, a support wall 36a protruding upward is provided on the side surface. The outer surface of the first base 32 and the first cover 35 is supported by the support wall 36a.
[0015]
In addition, the mounting portion 37 is provided on the inner side surface of the second rubber body 36, the area where the second rubber body 36 and the lower surface of the first base 32 abut is small, and is transmitted to the angular velocity sensor from the outside. The vibration / impact of the frequency is attenuated, and an angular velocity sensor having stable characteristics can be provided.
[0016]
Further, a first recess 38 is provided on the outer side surface in the longitudinal direction of the second rubber body 36. Reference numeral 39 denotes a first rubber body, which is provided so as to come into contact with the upper surface of the first cover 35 as shown in FIG. 6. A rectangular parallelepiped second recess 40 is formed on the lower surface of the first rubber body 39. At the same time, a step portion 41 is provided on the outer peripheral portion of the inner top surface portion of the second recess 40, and the step portion 41 is in contact with the upper surface of the first cover 35. Further, an escape recess 42 that protrudes further outward is provided on the inner surface of the first rubber body 39, and the end 43 of the long side of the portion excluding the escape recess 42 is in contact with the outer surface of the first cover 35. Touching.
[0017]
Since the first rubber body 39 is brought into contact with the upper surface of the first cover 35 and the second rubber body 36 is brought into contact with the lower surface of the first base 32, the vibration in the vertical direction is tuned to the tuning fork. As a result, the output characteristics are stabilized against vibrations in the vertical direction.
[0018]
Further, since the escape recess 42 protruding further outward is provided on the inner side surface of the first rubber body 39, the support wall 36a of the second rubber body 36 enters the escape recess 42 of the first rubber body 39. As a result, the first rubber body 39 is not lifted by the second rubber body 36 coming into contact with the first rubber body 39, so that the first base 32 and the first cover 35 are removed. It has the effect that it can support reliably.
[0019]
Further, the hardness of the second rubber body 36 and the hardness of the first rubber body 39 are made different, and the tuning fork 31a, the first cover 35, and the first base 32 are arranged at a portion far from the center of gravity. Since the hardness of the first rubber body 39 provided is made to be about 0.5 times that of the second rubber body 36 disposed in a portion close to the center of gravity, the impact force is applied to the angular velocity sensor. When loaded, no rotational moment is applied around the center of gravity of the tuning fork 31a, the first cover 35, and the first base 32. As a result, an angular velocity sensor with improved impact resistance can be provided. It has the effect.
[0020]
As shown in FIG. 7, a circuit board 44 is provided below the first base 32, and an electronic component 46 is provided on the upper surface and the lower surface. Output signal consisting of charges generated by the angular velocity from the third detection electrode 29 and the fourth detection electrode 30 of the second detection electrode 25, the second detection electrode 25, and the second vibrating body 26, and the flexible wiring board 47. The signal is input via the land portion 45 in the circuit board 44 and converted into an output voltage. The flexible wiring board 47 is bifurcated as shown in FIG. 8, and one of the detection electrode wiring portions 47a is divided into the first detection electrode 24, the second detection electrode 25, and the third detection electrode 29. Are electrically connected to the fourth detection electrode 30 and the other drive electrode wiring portion 47b is connected to the first drive electrode 22, the second drive electrode 23, the third drive electrode 28, and the fourth drive. The electrode 27 is electrically connected. The signal input to the drive electrode and the signal output from the detection electrode are separated from each other so that they do not affect each other.
[0021]
In addition, four groove portions 48 are provided on the side surface of the circuit board 44, and a terminal insertion hole 49 is provided in the circuit board 44. The power supply terminal 50, so as to protrude downward from the terminal insertion hole 49, The GND terminal 51 and the output terminal 52 are provided by soldering.
[0022]
A second metal base 53 is provided below the circuit board 44 and has five holes 54, and a power terminal 50, a GND terminal 51, and an output terminal 52 are provided in the holes 54. Is inserted through an insulator 55 made of glass.
[0023]
A second cover 56 is fixed to the upper surface of the second base 53, and the first base 32, the first cover 35, the second rubber body 36, the first rubber body 39, and the circuit board. 44 is provided so as to cover.
[0024]
A metal support plate 57 is provided with support legs 58 so as to protrude downward from the outer surface. The support legs 58 are fitted into the grooves 48 in the circuit board 44, and the tip ends of the support legs 58 are arranged. The second base 53 is in contact with the upper surface.
[0025]
Further, four wall portions 59 are provided so as to protrude downward from the upper surface of the support plate 57, and the four outer surfaces of the second rubber body 36 are positioned and fixed by the wall portions 59.
[0026]
At this time, four wall portions 59 are provided so as to protrude upward from the upper surface of the support plate 57, and the four side surfaces of the second rubber body 36 are positioned and fixed by the wall portions 59. Even if the second rubber body 36 tries to move due to the vibration in the direction, the four wall portions 59 suppress the movement, and as a result, an angular velocity sensor having improved characteristics with respect to the vibration in the lateral direction can be provided. It has the effect.
[0027]
Two of the four wall portions are provided with a contact portion 60 at the upper end, the lower surface of the first rubber body 39 is contacted with the contact portion 60, and the second cover 56 is attached to the first cover 56. By covering the rubber body 39, the support plate 57 is fixed to be pressed in the direction of the second base 53 via the first rubber body 39. A mounting portion 57a is provided on the upper portion of the support plate 57, and the second rubber body 36 is mounted on the upper surface of the mounting portion 57a. The first base 32 and the second rubber body 36 and the first rubber body 39 are compressed by the mounting portion 57a of the support plate 57 and the inner top surface portion of the second cover 56. The first cover 35 is supported.
[0028]
Next, a method for assembling the angular velocity sensor according to the embodiment of the present invention configured as described above will be described.
[0029]
First, a tuning fork 31a including a first vibrating body 21, a second vibrating body 26, and a connecting portion 31 is formed by bonding together thin quartz plates made of single crystals having different crystal axes.
[0030]
Next, the first drive electrode 22 on the front surface of the first vibrating body 21, the second drive electrode 23 on the back surface, the first detection electrode 24 on the outer surface, the second detection electrode 25 on the inner surface, the second The fourth drive electrode 27 is formed on the front surface of the vibrating body 26, the third drive electrode 28 is formed on the back surface, the fourth detection electrode 30 is formed on the inner surface, and the third detection electrode 29 is deposited on the outer surface by depositing gold. Form.
[0031]
Next, after inserting the terminal 34 through the terminal insertion hole 33 in the first base 32, the terminal insertion hole 33 is filled with an insulator (not shown) made of glass, The terminal 34 is fixed.
[0032]
Next, after the connecting portion 31 of the tuning fork 31a is fixed to the upper surface of the first base 32, the terminal 34 of the first base 32 is connected to the first drive electrode 22, the second drive electrode 23, the first Lead wires (not shown) made of gold for the detection electrode 24, the second detection electrode 25, the fourth drive electrode 27, the third drive electrode 28, the third detection electrode 29, and the fourth detection electrode 30, respectively. Connect by wire bonding.
[0033]
Next, the outer peripheral portion of the first base 32 is welded by a first cover 35 in a vacuum atmosphere so that the inside becomes a vacuum.
[0034]
Next, after mounting the electronic component 46 on the circuit board 44, the flexible wiring board 47 is soldered to the circuit board 44, and the flexible wiring board 47 is electrically connected to the electronic component 46.
[0035]
Next, after the power supply terminal 50, the GND terminal 51, and the output terminal 52 are inserted into the terminal insertion holes 49 in the circuit board 44, these terminals are soldered to the circuit board 44 to be electrically connected.
[0036]
Next, the support legs 58 of the support plate 57 are fitted into the grooves 48 in the circuit board 44.
[0037]
At this time, the lower end portion of the support leg 58 in the support plate 57 is configured to contact the upper surface of the second base 53.
[0038]
Next, after the second rubber body 36 is placed on the upper surface of the placement portion 57 a of the support plate 57, the first base 32 and the first cover 35 are further placed on the upper surface of the second rubber body 36. Put.
[0039]
Next, the first rubber body 39 is covered on the upper surface and the outer surface of the first cover 35, and the first cover 35 and the first base 32 are covered by the second rubber body 36 and the first rubber body 39. Pinch.
[0040]
Finally, the outer peripheral portion of the second base 53 is welded with the second cover 56, and the first rubber body 39 and the first cover 35 are placed inside the second cover 56 and the second base 53. The tuning fork 31a, the first base 32, the second rubber body 36, the support plate 57, and the circuit board 44 are accommodated.
[0041]
Next, the operation of the angular velocity sensor according to the embodiment of the present invention configured as described above will be described.
[0042]
An AC voltage is applied to the first drive electrode 22, the second drive electrode 23, the third drive electrode 28, and the fourth drive electrode 27 in the tuning fork. At this time, first, as shown in FIG. 10, when a positive voltage is applied to the second drive electrode 23 in the first vibrating body 21 and a negative voltage is applied to the first drive electrode 22, the first detection is performed. On the electrode 24 side, the direction of the crystal axis and the direction of the charge in the quartz thin plate coincide with each other, so that the electrode 24 extends, and on the second detection electrode 25 side, the direction of the crystal axis and the direction of the charge are opposite. As a result, the first vibrating body 21 tilts toward the second vibrating body 26. Next, as shown in FIG. 11, when a negative voltage is applied to the second drive electrode 23 in the first vibrating body 21 and a positive voltage is applied to the first drive electrode 22, the first detection electrode 24 is applied. On the side, the direction of the crystal axis and the direction of the charge in the quartz thin plate are opposite to each other, so that it contracts, and on the second detection electrode 25 side, the direction of the crystal axis and the direction of the charge are the same. As a result, the first vibrating body 21 is inclined outward.
[0043]
In addition, an AC voltage is similarly applied to the third drive electrode 28 and the fourth drive electrode 27 in the second vibrating body 26, and the first vibrating body 21 and the second vibrating body 26 are connected to each other. Since the first vibrating body 21 and the second vibrating body 26 are mechanically connected to each other by 31, the first vibrating body 21 and the second vibrating body 26 bend and vibrate at a speed V at a natural frequency in the driving direction in the longitudinal direction of the connecting portion 31. Further, when the tuning fork rotates at an angular velocity ω around the longitudinal center axis of the tuning fork in a state in which the first vibrating body 21 and the second vibrating body 26 are bendingly vibrated, the first vibrating body 21 and A Coriolis force of F = 2 mv · ω is generated in the second vibrating body 26. Due to this Coriolis force, an output signal composed of charges generated in the first detection electrode 24, the second detection electrode 25, the third detection electrode 29, and the fourth detection electrode 30 is sent to a lead wire (not shown). ), Converted into an output voltage by the electronic component 46 on the circuit board 44 via the terminal 34 and the flexible wiring board 47, and further on the other computer (not shown) via the output terminal 52 on the second base 53. The angular velocity is detected by inputting to.
[0044]
Here, considering the case where a strong impact force in the vertical direction is applied to the angular velocity sensor, in the angular velocity sensor according to the embodiment of the present invention, the contact portion 60 is provided at the upper ends of the two wall portions 59 of the support plate 57. The lower surface of the first rubber body 39 is brought into contact with the contact portion 60 and the second cover 56 is placed on the first rubber body 39 to thereby support the support via the first rubber body 39. The plate 57 is pressed in the direction of the second base 53. According to this configuration, even if a large impact force in the vertical direction is applied to the angular velocity sensor, the support plate 57 is moved by the inertial force to the second base 53. Since it is not separated from the upper surface of the base 53, no extra external force other than the Coriolis force generated by the angular velocity is applied to the tuning fork, and as a result, the angular velocity has a stable output characteristic against the vertical impact. Those having an effect that it is possible to provide a capacitor.
[0045]
【The invention's effect】
As described above, the angular velocity sensor of the present invention includes a tuning fork that outputs a signal in accordance with the angular velocity, a first base that fixes a part of the tuning fork to the upper surface, and a first base that is fixed to the first base. A first cover that covers the tuning fork, a first rubber body that contacts the upper surface of the first cover, a second rubber body that contacts the lower surface of the first base, and the second rubber body. A support plate whose upper surface is in contact with the lower surface of the rubber body, a second base whose upper surface is in contact with the support plate, the second base and tuning fork, a first base, a first cover, 1 with a rubber body, a second rubber body, and a bottomed cylindrical second cover that covers the support plate, and at least four wall portions are provided so as to protrude upward from the upper surface of the support plate. Since the four side surfaces of the second rubber body are positioned and fixed by the portion, the second rubber is caused by lateral vibration. Body also becomes the four walls to suppress the movement as attempts to move, since the tuning fork against the lateral vibration is eliminated that arises to move, together with the characteristics are improved with respect to external vibration, By providing a contact portion at the upper end of at least two wall portions of the support plate, contacting the lower surface of the first rubber body to the contact portion, and covering the first cover with the second cover Since the support plate is pressed in the direction of the second base through the first rubber body, even if a large impact force is applied to the angular velocity sensor in the vertical direction, the support plate is moved by the inertial force. Therefore, no extra external force other than the Coriolis force generated by the angular velocity is applied to the tuning fork, so that the output characteristics are stable against impacts in the vertical direction. Those having an effect of being able to provide a speed sensor.
[Brief description of the drawings]
1 is an exploded perspective view of an angular velocity sensor according to an embodiment of the present invention. FIG. 2 is a side sectional view and a side view of the angular velocity sensor. FIG. 3 is a perspective view of a tuning fork in the angular velocity sensor. FIG. 5 is a perspective view of the second rubber body in the angular velocity sensor. FIG. 6 is a perspective view of the first rubber body in the angular velocity sensor. FIG. FIG. 8 is a top view showing a state in which a flexible wiring board is soldered to a circuit board in the angular velocity sensor. FIG. 9 is a perspective view of a support plate in the angular velocity sensor. FIG. 10 is a tuning fork in the angular velocity sensor. FIG. 11 is a sectional view showing the operating state of the tuning fork in the angular velocity sensor. FIG. 12 shows a state in which the tuning fork is fixed to the base of the conventional angular velocity sensor. Perspective view Figure 13 is a side sectional view of the angular velocity sensor [Description of symbols]
31a tuning fork 32 first base 35 first cover 36 second rubber body 36a support wall 37 mounting portion 38 first recess 39 first rubber body 42 escape recess 53 second base 56 second Cover 57 support plate 59 wall 60 contact part

Claims (1)

A tuning fork that outputs a signal in accordance with an angular velocity, a first base that fixes a portion of the tuning fork to the upper surface, a first cover that is fixed to the first base and covers the tuning fork, A first rubber body in contact with the upper surface of the first cover; a second rubber body in which the upper surface is in contact with the lower surface of the first base; and a support in which the upper surface is in contact with the lower surface of the second rubber body. A plate, a second base whose upper surface is in contact with the support plate, the second base and tuning fork, a first base, a first cover, a first rubber body, a second rubber body, and A bottomed cylindrical second cover that covers the support plate, and at least four wall portions are provided so as to protrude upward from the upper surface of the support plate. By the wall portions, 4 in the second rubber body is provided. one of the well as positioning and fixing the side surface, a contact portion provided at the upper end of the at least two wall portions of the support plate, the abutment The lower surface of the first rubber body is brought into contact with the first rubber body, and the second cover is covered with the first rubber body, so that the support plate is directed toward the second base via the first rubber body. An angular velocity sensor designed to be pressed down.

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