JPH10197256A - Angular velocity detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oscillatory angular velocity detector capable of performing mass adjustment for the resonance frequency adjustment of a vibrating substance with small energy. SOLUTION: An injector 83 is filled up with pressurized air. When a current is caused to flow in an exciting coil 90, a plunger 86 is driven upwards, and air is jetted from a nozzle 85a. Besides, a laser beam which a laser oscillator 84 emits, passes the optical path 86b of the plunger 86, and is radiated form the center of the nozzle 85a. On the other hand, powder 102 of a low melting point metal or organic coating resin from a powder injection nozzle 100 is injected to the vicinity of the jet of the nozzle 85a. This powder 102 injected is irradiated with the laser beam 84a and melts, is blown off by air injected from the nozzle 85a, and adheres to the driving vibrating strip 13a of a vibrating body 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity detecting device for detecting an angular velocity using a Coriolis force acting on a vibrating body, and is particularly suitable for adjusting a resonance frequency of the vibrating body at low cost. The present invention relates to a simple angular velocity detecting device.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. Hei 4-50461.
As disclosed in Japanese Patent No. 7, there is known a vibration type angular velocity detecting device which detects a rotational angular velocity based on a Coriolis force acting when an excited vibrating body rotates. The conventional angular velocity detecting device has a vibrating body made of a piezoelectric material. The vibrating body is provided with a drive electrode and a detection electrode. When a drive voltage is applied to the drive electrode, the vibrating body is excited in a predetermined exciting direction by an inverse piezoelectric effect of the piezoelectric body. When the vibrating body rotates in such an excited state, the vibrating body generates vibration having an amplitude proportional to the rotational angular velocity in a direction perpendicular to the exciting direction (hereinafter, referred to as a detection direction) due to the Coriolis force. Due to the piezoelectric effect of the piezoelectric body, electric charges are generated in the vibrating body according to the vibration due to the Coriolis force. Such charges are detected through the detection electrodes, and the magnitude of the angular velocity is detected based on the detected value.

In the above-described conventional angular velocity detecting device, the vibrating body is excited at a resonance frequency fx in an exciting direction in order to realize efficient excitation. In order to improve the angular velocity detection sensitivity, the resonance frequency fz in the detection direction of the vibrating body is required.
To fx. However, in this case, there is a time delay from the time when the Coriolis force starts to act until the vibration in the detection direction appears, so that the detection response of the angular velocity decreases. On the other hand, when the difference between the two resonance frequencies fx and fz increases, the vibration amplitude of the vibrating body in the detection direction decreases, and the detection sensitivity of the angular velocity decreases. Therefore, in order to achieve a good balance between the detection sensitivity and the responsiveness, the frequency difference Δf between the resonance frequency fx in the excitation direction and the resonance frequency fz in the detection direction must be adjusted with high accuracy. For this purpose, in the conventional angular velocity detecting device, the frequency difference is adjusted by depositing gold on the vibrating body, or changing the mass of the vibrating body by melting and removing gold previously deposited. I do.

[0004]

However, since gold has a high melting point, a large amount of energy is required to deposit and remove gold. For this reason, according to the conventional angular velocity detecting device, the manufacturing cost of the device increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a vibration type angular velocity detecting device capable of adding mass for adjusting a resonance frequency of a vibrating body at low cost. Aim.

[0006]

An object of the present invention is to provide a vibrating body, an exciting means for exciting the vibrating body, and a vibration of the vibrating body caused by a Coriolis force acting when the excited vibrating body rotates. In the angular velocity detecting device comprising: a vibration detecting means for detecting the angular velocity of the rotation of the vibrating body based on the vibration detected by the vibration detecting means, the resonance frequency of the vibrating body, This is achieved by an angular velocity detecting device adjusted by changing the amount of the low melting point substance attached to the vibrating body.

In the present invention, the resonance frequency of the vibrating body is
It is adjusted by changing the amount of the low melting point substance attached to the vibrator. Since the low-melting substance is melted at a low temperature, the energy required for attaching or removing the low-melting substance to or from the vibrator is small. Therefore, the energy required for adjusting the frequency of the vibrating body is suppressed to a small value.

[0008]

FIG. 1 is a perspective view of an angular velocity detecting device according to one embodiment of the present invention. As shown in FIG. 1, the angular velocity detecting device according to the present embodiment includes a detecting unit 10 and a substrate 11. The detecting unit 10 includes a vibrating body 12 and a base 20. The detection unit 10 is mounted on the board 11 by mounting and fixing the base 20 to the board 11. As described later, a processing circuit for exciting the vibrating body 12 of the detection unit 10 and detecting an angular velocity based on the vibration state is mounted on the substrate 11.

FIG. 2 is a perspective view of the detecting unit 10. As shown in FIG. In FIG. 2, the XYZ axes are orthogonal to each other,
In the figure, the left direction is defined as positive, the left and right direction is defined as the Y axis, the upward direction is defined as positive, the up and down direction is defined as the Z axis, the upper right direction is defined as positive, and the direction from the upper right to the lower left is defined as the X axis. The detection unit 10 shown in FIG. 2 is made of single crystal quartz. Detection unit 10
Is formed such that the optical axis direction coincides with the Z axis direction, the mechanical axis direction coincides with the Y axis direction, and the electric axis direction coincides with the X axis direction with respect to the crystal axis of quartz crystal. As shown in FIG. 2, the vibrating body 12 includes two vibrating pieces 13 and 14 extending parallel to each other in the Y-axis direction. The vibrating bars 13 and 14 are longitudinal members having the same rectangular cross-sectional shape and the same length, and are connected to each other by a connecting portion 16 extending in the X-axis direction at the center in the Y-axis direction. The connecting portion 16 is connected to the base 20 via the connecting portion 18 at the center in the X-axis direction. Thus, the vibrating body 1
Reference numeral 2 has a symmetrical shape with respect to an axis parallel to the Y axis, and integrally constitutes a tuning fork that resonates.

The vibrating body 12 has the following main resonance modes:
A resonance mode in which the vibrating bars 13 and 14 vibrate in opposite phases in a plane parallel to the XY plane (hereinafter referred to as a first resonance mode), and a vibrating bar 13 and 14 in opposite phases in a plane parallel to the YZ plane. (Hereinafter, referred to as a second resonance mode). As described later, in the present embodiment, the first resonance mode is used for exciting the vibrating body 12, and the second resonance mode is used for detecting the Coriolis force.

The portions of the vibrating bars 13, 14 extending in the + Y direction from the connecting portion 16 function as drive vibrating bars 13a, 14a for exciting the vibrating body 12 in the first resonance mode.
The portions extending in the −Y direction from 6 function as detection vibrating reeds 13b and 14b that detect the vibration of the vibrating body 12 in the second resonance mode.

FIG. 3 shows that the driving oscillators 13a and 14a are XZ
FIG. 3 shows a cross-sectional view when cut along a plane parallel to the plane. FIG. 4 is a cross-sectional view of the detection vibrating pieces 13b and 14b cut along a plane parallel to the XZ plane. As shown in FIG. 3, the drive electrode 2 is provided on each side surface of the drive vibrating pieces 13a and 14a.
2a to 22d and 24a to 24d are provided to extend in the Y-axis direction. As shown in FIG. 4, a pair of detection electrodes 26a, 26b, 26c, and 26d are provided on two side surfaces of the detection vibrating piece 13b parallel to the XY plane, respectively.
Also, a pair of detection electrodes 28a, 28b, and 28
c and 28d are provided so as to extend in the Y-axis direction, respectively.

Excitation of the vibrating body 12 in the first resonance mode and detection of vibration of the vibrating body 12 in the second resonance mode are performed by a processing circuit mounted on the substrate 11. Less than,
The configuration and operation of such a processing circuit will be described with reference to FIGS. FIG. 5 is a block diagram of the processing circuit. As shown in FIG. 5, the processing circuit includes an excitation circuit 40, a detection circuit 50, and an angular velocity calculation circuit 70.

The excitation circuit 40 includes a current-voltage conversion circuit 42,
An automatic gain control circuit 44 and a drive circuit 46 are provided. The input terminal and the output terminal of the current / voltage conversion circuit 42
Each is connected to a terminal 48 and an input terminal of the automatic gain control circuit 44. The output terminal of the automatic gain control circuit 44 is connected to the input terminal of the drive circuit 46. The output terminal of the drive circuit 46 is connected to the terminal 49. The terminals 49 include drive electrodes 22b and 22d provided on two sides parallel to the YZ plane of the drive vibrating piece 13a, and drive electrodes 24a provided on two side faces parallel to the XY plane of the drive vibrating body 14a. , 24c are connected. Terminal 4
8, other drive electrodes 22a, 22c, 24b, 24d
Is connected.

The detection circuit 50 includes current-voltage conversion circuits 52 and 54, a differential amplifier circuit 56, and a synchronous detection circuit 58. The input terminals of the current-voltage conversion circuits 52 and 54 are connected to terminals 60 and 62, respectively, and the output terminal thereof is connected to the input terminal of the differential amplifier circuit 56. The output terminal of the differential amplifier circuit 56 is connected to the input terminal of the synchronous detection circuit 58, and the output terminal of the synchronous detection circuit 58 is connected to the terminal 64. Terminal 60 includes
The detection electrodes 26a and 26c are provided diagonally opposite to the cross section of the detection vibration piece 13b, and the detection vibration piece 14b is opposed to the detection electrodes 26a and 26c in a symmetrical direction. Provided detection electrode 28
b and 28d are connected. The other detection electrodes 26b, 26d, 28a, and 28c are connected to the terminal 62. Further, an input terminal of the angular velocity calculation circuit 70 is connected to the terminal 64.

Next, the operation of the processing circuit will be described. The drive circuit 46 outputs a pulse wave having a predetermined frequency with an amplitude corresponding to the voltage value input from the automatic gain control circuit 44, and outputs a signal having a phase shifted from the pulse wave by 90 ° to the synchronous detection circuit 58. It is configured so as to be provided as a detection signal to the target. Therefore, the drive electrode 22b,
A pulse wave output from the drive circuit 46 is applied to 22d, 24a, and 24c. The driving electrodes 22a, 22
Since c, 24b, and 24d are connected to the input terminal of the current-voltage conversion circuit 42 via the terminal 48, the potentials of these electrodes are maintained at the intermediate potential of the pulse wave output from the drive circuit 46.

FIG. 6 is a diagram showing an electric field acting on the driving vibrating piece 13a when the driving circuit 46 outputs a low level. FIG. 6 shows a cross section taken along a plane parallel to the XZ plane as in FIG. It is shown in the figure. FIG. 7 is a diagram showing a deformation occurring in the driving vibrating piece 13a when the driving circuit 46 outputs a pulse wave.

The driving circuit 46 drives the driving electrodes 22b, 2
When a low-level voltage is applied to 2d, the drive electrode 2
Since the potentials of 2a and 22c are maintained at the intermediate potential of the pulse wave, as shown by arrows 72 to 75 in FIG. 6, the inside of the driving vibration piece 13a goes from the driving electrodes 22a and 22c to the driving electrodes 22b and 22d. An electric field is generated, and the reverse piezoelectric effect of the crystal appears due to the electric field. However, the electric field in the optical axis direction of the crystal, that is, the Z direction does not contribute to the inverse piezoelectric effect. For this reason, the effective electric field that causes the inverse piezoelectric effect appears, as shown by arrows 76 and 77 in FIG.
In the section of 3a, the electric field becomes + X on the + X side from the neutral plane 79 parallel to the YZ plane, and − on the −X side from the neutral plane 79.
It becomes an electric field in the X direction. Therefore, in the state shown in FIG. 6, the driving vibrating reed 13a
It deforms so that the + X side extends from the neutral surface 79 and the −X side contracts from the neutral surface 79. That is, the driving vibrating piece 13a has -X
Bending deformation occurs such that the side is on the inside. On the other hand, when the driving circuit 46 is outputting a high-level voltage, the direction of the electric field acting on the driving vibrating reed 13a is reversed, so that the driving vibrating reed 13a is bent so that the + X side is inside. Deformation occurs. Accordingly, when the driving circuit 46 outputs a pulse wave, the driving vibrating piece 13a becomes XY as shown in FIG.
Bending vibration occurs in the plane.

On the other hand, with respect to the drive vibrator 14a, a pulse wave output from the drive circuit 46 is applied to the drive electrodes 24a and 24c facing in a direction perpendicular to the direction in which the drive electrodes 22b and 22d face. For this reason, the direction of the electric field acting on the driving vibrating body 14a is opposite to that of the driving vibrating piece 13a, and the direction of the bending deformation of the driving vibrating body 14a is also changed.
The direction is opposite to 3a. Therefore, when the drive circuit 46 outputs a pulse wave, vibrations having phases opposite to each other are generated in the drive vibration pieces 13a and 14a. Such driving vibrating pieces 13a, 14
Due to the vibration of a, the vibrating body 12 is excited in its first resonance mode.

When the driving vibrating pieces 13a and 14a vibrate in the XY plane, electric charges corresponding to the deformation of the driving vibrating pieces 13a and 14a are generated in the driving electrodes 22a, 22c, 24b and 24d due to the piezoelectric effect of quartz. Such charges are input to the current-voltage conversion circuit 42 via the terminal 48. The DC voltage conversion circuit 42 is configured to convert the amount of change in the input charge into a voltage signal. Therefore, the DC voltage conversion circuit 4
2 outputs a voltage signal corresponding to the vibration of the driving vibrating bars 13a and 14a to the automatic gain control circuit 44. The automatic gain control circuit 44 is configured to decrease the output voltage when the amplitude of the input signal voltage increases. Therefore, the voltage signal output from the automatic gain control circuit 44 to the drive circuit 46 decreases in accordance with the increase in the vibration amplitude of the drive vibrating reeds 13a and 14a, whereby the drive circuit 46 drives the drive electrodes 22b and 22d. , 24a and 24c are reduced in amplitude. Thus, the amplitude of the pulse signal output from the drive circuit 46 is
By performing feedback control based on the vibration amplitudes of 3a and 14a, the vibration amplitudes of the driving vibrating pieces 13a and 14a are kept constant, and therefore, the vibration amplitude of the vibrating body 12 in the first resonance mode is kept constant. You.

As described above, in a state where the driving vibrating pieces 13a and 14a are excited, that is, in a state where the vibrating body 12 is excited in the first resonance mode, the detecting unit 10 rotates around the axis parallel to the Y axis. When the movement occurs, a Coriolis force Fc in the Z direction acts on the vibrating bars 13 and 14 in proportion to the product of the vibration velocity v and the angular velocity ω of the rotation. That is, a Coriolis force of Fc = 2 · m · v · ω (1) acts on the vibrating body 12. Here, m is the resonator element 13,
14 mass.

In the first resonance mode, the resonator elements 13, 1
4 vibrate in opposite phases to each other, so that the vibrating pieces 13 and 14
Also change in opposite phases. Due to such Coriolis force, the vibration of the first resonance mode is superimposed on the vibration of the vibration body 12 in the second resonance mode, which is 90 ° out of phase with the vibration. Due to the vibration of the vibrating body 12, the detection vibrating pieces 13b and 14b
And the detection electrodes 26a to 26d respectively provided in
Electric charges corresponding to the vibration of the detection vibrating reeds 13b and 14b are generated in 28a to 28d by the piezoelectric effect of quartz.

FIG. 8 shows the detected vibrating reed 1 with the vibration of the vibrating body 12 excited by the Coriolis force in the second resonance mode.
FIG. 3b shows a state in which vibration occurs in a plane parallel to the YZ plane. FIG. 9 is a diagram showing a state of polarization generated in the detection vibration piece 13b when the detection vibration piece 13b is deformed in the + Z direction. This is shown in a sectional view.

When the detecting vibrating piece 13b is deformed in the + Z direction, the + Z side of the neutral plane 80 parallel to the XY plane of the cross section shrinks in the Y-axis direction and the -Z side of the neutral plane 80 extends in the Y-axis direction. For this reason, from the neutral surface 80 of the detection vibration piece 13b, +
In the half on the Z side, polarization in the + X direction occurs as shown by an arrow 81 in FIG. 9, and in the half on the −Z side from the neutral plane 80, polarization in the −X direction occurs as shown by an arrow 82. Due to such polarization, positive charges are generated on the detection electrodes 26a and 26c, and negative charges are generated on the detection electrodes 26b and 26d.
The polarization increases as the deformation of the detection vibrating piece 13b in the Z direction increases. Therefore, the detection electrodes 26a-2
The amount of charge generated in 6d increases as the deformation of the detection vibrating piece 13b increases.

Similarly, when the detection vibration 14b is deformed in the Z direction, charges corresponding to the deformation are generated in the detection electrodes 28a to 28d. However, since the detection vibration piece 14b vibrates in the opposite phase to the detection vibration piece 13b, in a state where the detection vibration piece 13b is deformed in the positive Z direction, the detection vibration piece 14b
Direction, the detection electrodes 28b and 28d have positive charges, and the detection electrodes 28a and 28c have negative charges.
Each occurs. That is, when vibrations in the YZ plane occur in the detection vibrating pieces 13b and 14b, the detection electrodes 26a and 26b
c, 28b, 28d and detection electrodes 26b, 26d, 28
Charges of the same polarity are always generated in a and 28c.

The detection electrodes 26a to 26d, 28a to
28d also generates electric charges due to the vibration of the detection vibrating reeds 13b and 14b in the XY plane, that is, the vibration due to the vibration of the vibrating body 12 in the first resonance mode. The influence of the electric charge generated by the vibration of the first resonance mode is removed, and only the electric charge of the component generated by the vibration of the second resonance mode due to the Coriolis force is detected.

As described above, the detection electrodes 26a, 26c, 2
8b, 28d and detection electrodes 26b, 26d, 28
The charges generated at a and 28c are input to the current-voltage conversion circuits 52 and 54 via terminals 60 and 62, respectively. The current-voltage conversion circuits 52 and 54 output a voltage signal corresponding to the amount of change in the input charges to the differential amplifier circuit 56, and the differential amplifier circuit 56 amplifies and outputs the voltage difference between these signals. . Therefore, the output signal voltage of the differential amplifier circuit 56 changes according to the vibration of the detection vibrating bars 13b and 14b.

The synchronous detection circuit 58 is configured to synchronously detect the signal input from the differential amplifier circuit 56 using the detection signal provided from the drive circuit 46 of the excitation circuit 40, and then perform an integration process. ing. As described above, the phase of the detection signal is shifted by 90 ° from the phase of the output pulse wave,
Therefore, the phase of the vibration in the first resonance mode is shifted by 90 °. Further, as described above, the phase of the vibration in the second resonance mode caused by the Coriolis force is shifted by 90 ° from the phase of the vibration in the first resonance mode. Accordingly, the synchronous detection circuit 58 performs synchronous detection based on the detection signal as described above, whereby the signal component generated by the vibration in the first resonance mode is canceled, and the signal component generated by the vibration in the second resonance mode due to the Coriolis force. Only those are extracted and integrated. As a result, the output signal voltage of the synchronous detection circuit 58 changes according to only the vibration of the detection vibrating bars 13b and 14b due to the Coriolis force.

The output signal of the synchronous detection circuit 58 is input to the angular velocity calculation circuit 70. The angular velocity calculation circuit 70 calculates a rotational angular velocity ω about an axis parallel to the Y axis acting on the detection unit 10 based on the input signal using the relationship of the equation (1). In the configuration of the angular velocity detecting device described above, the drive circuit 46 outputs a pulse wave having a frequency substantially equal to the resonance frequency fx of the vibrating body 12 in the first resonance mode.
The vibration of the vibrating body 12 in the first resonance mode is excited with high efficiency. In this case, the Coriolis force also varies at the frequency fx. Therefore, if the resonance frequency fz of the second resonance mode of the vibrating body 12 coincides with fx, the vibration of the second resonance mode of the vibrating body 12 is also excited with high efficiency by the Coriolis force. Obtainable. However, the vibrating body 12 has its resonance frequency fz
Excitation at an excitation frequency equal to requires a large amount of energy. For this reason, when the resonance frequency fx coincides with fz, high detection sensitivity can be obtained, but energy storage for energy storage is performed after the Coriolis force starts to act on the vibrating body 12 until vibration of the second resonance mode occurs. A time delay occurs, and the detection response is reduced.

On the other hand, when there is a frequency difference Δf between the resonance frequencies fx and fz, as Δf increases, the excitation efficiency of the second resonance mode due to the Coriolis force decreases, so that the angular velocity detection sensitivity decreases. Since the energy required to excite the vibration in the second resonance mode is reduced, the detection response is improved. That is, it is preferable to reduce Δf in order to improve the detection sensitivity of the angular velocity detecting device, and it is preferable to increase Δf in order to improve the response. Therefore, in order to balance the securing of the detection sensitivity and the securing of the responsiveness of the angular velocity detecting device in a well-balanced manner, it is necessary to adjust the resonance frequencies fx and fz and set Δf to an optimal value. In the angular velocity detecting device of the present embodiment, it is required to set Δf to, for example, 2% of fx.

The resonance frequencies fx and fz of the vibrating body 12 in each resonance mode are determined by the geometric configuration and the mass of the vibrating body 12. Since the detection unit 10 is formed by etching, it is difficult to set Δf with high accuracy depending on the processing shape in consideration of the processing error. Therefore,
To set the resonance frequency difference Δf to a desired value, the detection unit 1
After the zero forming, it is necessary to adjust the mass of the vibrating body 12 by some method.

FIG. 10 is a diagram showing the relationship between Δm and the resonance frequencies fx and fz when masses Δm are added to the ends of the driving vibration pieces 13a and 14a, respectively. As shown in FIG. 10, both fx and fz decrease as Δm increases. However, since the degree of decrease of fz is greater, Δf changes as Δm increases. In FIG. 10, Δm
Is 0.4 mg, Δf is 2% of fx, and by adding a mass of 0.4 mg, Δf
It can be seen that f can be set to a desired value.

As a method for adjusting the Δf of the vibrating body 12 with high accuracy by adjusting the mass, it is possible to add a mass by vapor-depositing gold on the vibrating body 12 or to melt and remove gold previously deposited. And so on. However,
If the mass is adjusted by vapor deposition of gold, since the melting point of gold is high, a large amount of energy is required for the vapor deposition, which increases the manufacturing cost of the angular velocity detector.
Further, since the adjustment of Δf is performed in the vacuum device, the adjustment process must be performed as a batch process, and it is difficult to individually and precisely adjust each device. Furthermore, since the angular velocity detector is used in the atmosphere, if Δf is adjusted in a vacuum, it is necessary to consider the change in the resonance frequency between the vacuum and the atmosphere, and the adjustment procedure of Δf is required. It becomes complicated. Further, when the mass is adjusted by melting and removing gold, since the melting point of gold is high as described above, a large amount of energy is required to melt gold, and the manufacturing cost of the angular velocity detecting device increases. Would.

The angular velocity detecting device of this embodiment is characterized in that the mass adjustment of the vibrating body 12 for adjusting Δf can be performed at low cost in an atmospheric environment. Hereinafter, such a characteristic portion of the present embodiment will be described. FIG. 11 is a diagram illustrating a method of adding mass to the vibrating body 12 in the present embodiment. In this embodiment, a thermosetting resin solvent is sprayed on the ends of the driving vibrating pieces 13a and 14a by the injector 83, and the resin solvent is thermally hardened by the laser light 84a emitted from the laser oscillator 84.

As shown in FIG. 11, the injector 83 has a housing 85. The housing 85 has a nozzle 85a at the lower end in FIG. A plunger 86 made of a magnetic material is provided inside the housing 85. A valve body 86a is provided at the lower end of the plunger 86 in FIG. The plunger 86 has an optical path 86b penetrating in the axial direction. Further, the plunger 86 has a core portion 8 formed with a larger diameter than other portions.
6c. The plunger 86 is urged by a spring 88 so that the valve body 86a closes the nozzle 85a.

An excitation coil 9 is provided on the outer periphery of the housing 85.
0 is provided. When the excitation coil 90 is energized,
The plunger 86 is driven upward in FIG. 11 against the urging force of the spring 88 by the electromagnetic attraction force acting on the core portion 86c, and the nozzle 85a is opened. The inside of the housing 85 is, for example, 10 to 10 through an inlet 85b.
A thermosetting resin solvent 92 pressurized to 200 MPa is filled. Therefore, when the excitation coil 90 is energized,
The thermosetting resin solvent 92 is ejected from the nozzle 85a.
In this case, the injection amount of the thermosetting resin solvent 92 in one injection can be adjusted by the ON time of the current applied to the excitation coil 90.

A transparent window 85c is provided at a portion of the upper surface of the housing 85 in FIG. 11 which is located on the extension of the light path 86b of the plunger 86. The laser oscillator 84
The oscillating laser light 84a is arranged so as to pass through the optical path 86b of the plunger 86 via the transparent window 84b and to be emitted from the center of the nozzle 85a. Therefore, the injection of the thermosetting resin solvent 92 by the injector 83 and the irradiation of the laser beam 85a are performed in the same direction.
A shutter 94 is provided in a portion of the optical path of the laser light 84a between the laser oscillator 84 and the injector 83. Opening and closing of the shutter 94 controls on / off of the laser light 84a emitted from the nozzle 85a of the injector 83.

The angular velocity detecting device converts the thermosetting resin solvent 92 injected by the injector 83 into the driving vibrating piece 13.
It is movably installed below the injector 83 so that it can be attached to the end of the driving vibration piece 14a. Therefore, after injecting the thermosetting resin solvent 92 with the shutter 94 closed, the shutter 9
4 is opened, and the thermosetting resin solvent 92 attached to the driving vibrating piece 13a or 14a is heated and hardened by the laser beam 84a, whereby the mass can be added.

When different masses are added to the driving vibrating bars 13a and 14a, the vibration amplitudes of the vibrating bars 13 and 14 differ. In this case, the charge generated on the detection electrodes 26a to 26d of the detection vibration piece 13b and the detection vibration piece 1
4b, the balance between the charges generated on the detection electrodes 28a to 28 is lost, which causes an error in the angular velocity obtained by the detection circuit 50 and the angular velocity calculation circuit 70. For this reason, in the present embodiment, by adding a small amount of mass to the detection vibrating reeds 13a and 14a alternately, while maintaining the mass balance between the vibrating reed 13 and the vibrating reed 14,
f is to be adjusted.

In the above processing circuit, the frequency of the output signal of the current-voltage conversion circuit 42 matches the resonance frequency fx of the vibrating body 12 in the first resonance mode. Further, the frequency of the output signal of the differential amplifier circuit 56 matches the resonance frequency fz of the vibration body 12 in the second resonance mode. Therefore, by detecting the frequencies of these output signals using a frequency counter, Δf can be monitored in real time. Therefore, in the present embodiment, when adjusting Δf by adding mass to the vibrating body 12, while monitoring Δf by the above-described method, the driving vibrating pieces 13 a and 1
By adding a small amount of mass to 4a alternately and stopping mass addition when Δf reaches a desired value, highly accurate adjustment of Δf can be realized without measuring the added mass. .

As described above, in this embodiment, Δf is adjusted by adhering the thermosetting resin solvent 92 in a molten state at room temperature. For this reason, it is not necessary to apply energy to melt the adhered substance, and the output of the laser oscillator 84 is sufficient to increase the temperature of the thermosetting resin to its curing temperature (for example, about 200 ° C.). is there. In addition, since the energy absorption rate of the resin is generally high, the heating of the thermosetting resin solvent 92 by the laser beam is efficiently performed. As described above, in the present embodiment, the power of the laser beam required for adding the mass to the vibrating body 12 for the adjustment of Δf is reduced, so that relatively low-output and low-cost CO ₂ It is possible to use a laser or a YAG laser, thereby suppressing the manufacturing cost of the angular velocity detecting device.

An optical lens may be provided in the optical path of the laser beam 84a so that the laser beam 84a is focused on the thermosetting resin solvent 92 attached to the vibrator. In this case, the energy of the laser light 84a can be used more efficiently, and the output of the laser oscillator 84 can be further reduced.

Also, instead of adding mass to the ends of the driving vibrating bars 13a, 14a, the detecting vibrating bars 13b, 14b
The same effect can be obtained by adding mass to the end of the. Next, a second embodiment of the present invention will be described with reference to FIG. Note that FIG.
The same components as those in 1 are denoted by the same reference numerals and description thereof will be omitted. The present embodiment is characterized in that mass addition to the vibrating body 12 for adjusting the frequency difference Δf is performed using a finely divided organic paint resin.

As shown in FIG. 12, a fine powder supply nozzle 100 is provided below the injector 83. The fine powder supply nozzle 100 is configured to inject the fine powder 102 of the organic paint resin from the side toward the vicinity of the injection port of the nozzle 85a. An inlet 85 is provided inside the housing 85.
b is filled with air pressurized. Therefore, when the exciting coil 90 is energized to open the nozzle 85a, air is ejected from the nozzle 85a.
Injection of air from this nozzle 85a and fine powder supply nozzle 1
At the same time as the ejection of the fine powder 102 from 00, the shutter 94 is opened to irradiate the injected fine powder 102 with the laser beam 84a. Since the organic coating resin has a property of melting when heated, the fine powder 102 is melted by the irradiation of the laser beam 84a, and the melted fine powder 102 is blown off by the air injected from the nozzle 84a to be driven by the driving vibrating piece. 13a. The fine powder 102 adhered to the driving vibration piece 13a is hardened by natural cooling by closing the shutter 94 and blocking the laser beam 84a.

In this embodiment, as in the case of the first embodiment, by monitoring the Δf, the fine powder 102 is adhered little by little, whereby the Δf can be accurately adjusted. Further, since the organic coating resin has a relatively low melting temperature (about 200 ° C.), a high-output laser oscillator 84 is used.
It is not necessary to use. Therefore, also in this embodiment, as in the first embodiment, it is possible to reduce the manufacturing cost of the device. When the laser beam 84a is condensed by using a lens, the focal position of the laser beam 84a may be set to the fine powder 102 ejected from the fine powder ejection nozzle 100.

Next, a third embodiment of the present invention will be described. The present embodiment is characterized in that fine powder of a low melting point metal is used instead of the fine powder 102 of the thermosetting resin in the second embodiment. The other configuration and the method of adhering the fine powder to the vibrating body 12 are the same as those in the second embodiment, and the description is omitted. In this embodiment, as the low-melting point metal, for example, an alloy containing copper, silver, tin, lead, aluminum, and zinc as main components and having a melting point of 1100 ° C. or less can be used. In this case, the vibrating body 1 made of quartz
In order to improve the adhesion to No. 2, it is preferable that the contents of copper and silver contained in the low-melting-point metal 114b are each 10% by weight or more.

Next, a fourth embodiment of the present invention will be described with reference to FIG. 13, the same components as those in FIG. 11 are denoted by the same reference numerals, and the description thereof will be omitted. The present embodiment is characterized in that mass addition to the vibrating body 12 for adjusting Δf is performed by melting and attaching a low melting point metal formed in a wire shape.

As shown in FIG. 13, below the injector 83, a metal wire 114 guided and driven by rollers 110 and 112 is disposed so as to cross the front of the injection port of the nozzle 85a. FIG. 14 shows a metal wire 114.
FIG. 2 shows a perspective view of a state in which is cut. As shown in FIG. 14, the metal wire 114 is formed by coating a thin wire 114a made of a high melting point alloy mainly containing tungsten, iron and nickel with a layer of a low melting point metal 114b. As the low melting point metal 114b, copper as in the third embodiment,
An alloy containing silver, tin, lead, aluminum, and zinc as main components can be used.

Referring again to FIG. 13, the injector 8
The inside of the third housing 85 is filled with air pressurized from an inlet 85b. Therefore, when the nozzle 85a is opened, air is jetted from the nozzle 85a. When adding mass to the vibrating body 12, the metal wire 114
The low-melting-point metal 114b is melted by irradiating the metal wire 114 with the laser beam 84a while the shutter 94 is in the open state while driving. Then, by blowing air from the nozzle 85a in synchronization with this, the molten low-melting-point metal 114b is blown off and adhered to the vibrating body 12.

In this embodiment, as in the case of the first and second embodiments, it is possible to accurately set Δf by monitoring a small amount of the low-melting metal 114b while monitoring Δf. it can. By the way, as described above,
In the case where the adjustment of f is performed by adding a mass to the vibrating body 12, the larger the specific gravity of the attached material, the more efficient the frequency adjustment can be performed. From this viewpoint, the third
It is preferable to add the mass using a metal material as in the fourth embodiment, and it is further preferable to use a metal material having a larger specific gravity. However, in the third and fourth embodiments, since the low melting point metal is attached to the vibrating body 12 in a state of being melted by the laser, the low melting point metal is prevented from being damaged by the heat. Melting point, specific heat, and particle size of fine powder (in the case of the third embodiment)
Alternatively, it is necessary to appropriately set the thickness of the low melting point metal 114b layer (in the case of the fourth embodiment).

FIG. 15 shows ranges of the melting point, the specific heat, and the fine particle diameter of the low melting point metal which are optimally added to the vibrating body 12 and which are found experimentally by the present inventor. In FIG. 15, the x-axis indicates specific heat (cal / deg · g), the y-axis indicates fine particle size (μm), and the z-axis indicates melting point (° C.).
As shown in FIG. 15, there is an optimum range for each parameter. That is, if the specific heat is too small, the molten metal tends to cool and solidify before reaching the vibrating body 12, and if the specific heat is too large, it is difficult to cool after adhering to the vibrating body 12. Therefore, there is a possibility that the temperature of the vibrating body 12 is locally increased and the vibrating body 12 is damaged. Therefore, the specific heat is 0.01 to 0.15 (cal / deg).
・ Optimally within the range of g). Also, if the particle size of the fine powder is too small, the jetting performance from the fine powder nozzle 100 is reduced, and if the particle size of the fine powder is too large, the fine powder is difficult to melt. For this reason, the fine powder particle size is optimally in the range of 0.1 to 7 μm. Furthermore, if the melting point is too low, it may melt within the operating temperature range of the angular velocity detector,
On the other hand, if the melting point is too high, a large amount of energy is required for melting. Therefore, the melting point is 180 to 1250.
Most preferably, it is in the range of ° C. However, if the particle size increases, the fine particles become difficult to dissolve, so the upper limit of the optimum range of the melting point decreases as the particle size increases, and when the maximum particle size is 7 μm, the optimum range of the melting point is 180 to 900 ° C. Has become.

By using a low melting point metal having the above-mentioned range of parameters, a high-power laser beam can be used to melt the low melting point metal without causing thermal damage or cracks in the vibrating body 12. No, vibrating body 12
It has been experimentally confirmed that the mass adjustment, that is, the adjustment of Δf can be performed.

As described above, in the third and fourth embodiments, the low-melting point metal having a melting point of 180 to 1250 ° C. is used, so that the vibrating body 12 is formed in the same manner as in the first and second embodiments.
It is possible to suppress the energy required for adding a mass to the motor, thereby making it possible to adjust Δf with high accuracy without increasing the manufacturing cost of the angular velocity detecting device.

In the first to fourth embodiments,
The drive electrodes 22a to 22d, 24a to 24d, and the excitation circuit 40 are connected to the above-described excitation means by the detection electrodes 26a to 26d.
d, 28a to 28d, and the detection circuit 50 is for the above-described vibration detection means, the angular velocity calculation circuit 70 is for the above-described angular velocity detection means, and the thermosetting resin solvent 85b, the fine powder 102, and the low melting point metal 114a are for the above-mentioned low vibration detection means. Each corresponds to a melting point material.

[0055]

As described above, according to the present invention, the energy required for adjusting the mass of the vibrating body for adjusting the resonance frequency of the vibrating body can be suppressed. Thereby, the manufacturing cost of the angular velocity detecting device can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of an angular velocity detecting device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a detection unit of the angular velocity detection device according to the embodiment.

FIG. 3 is a cross-sectional view of the driving vibrating reed of the detection unit of the present embodiment.

FIG. 4 is a cross-sectional view of a detection vibrating reed of a detection unit according to the present embodiment.

FIG. 5 is a block diagram of a processing circuit of the angular velocity detecting device according to the embodiment.

FIG. 6 is a diagram illustrating an electric field acting on a driving vibrating piece when a voltage is applied to a driving electrode.

FIG. 7 is a diagram showing vibration generated in a driving vibrating reed when a pulse voltage is applied to a driving electrode.

FIG. 8 is a diagram showing vibration generated in a detection vibrating reed by Coriolis force.

FIG. 9 is a diagram illustrating an electric field generated in the detection vibrating piece and a charge generated in the detection electrode when the detection vibrating piece is deformed in the + Z direction.

FIG. 10 is a diagram illustrating a relationship between an additional mass Δm applied to a vibrating body and resonance frequencies fx and fz.

FIG. 11 is a diagram illustrating a method of adding mass to the vibrating body in the present embodiment.

FIG. 12 is a diagram illustrating a method of adding mass to a vibrating body in a second embodiment of the present invention.

FIG. 13 is a diagram illustrating a method for adding mass to a vibrating body in a fourth embodiment of the present invention.

FIG. 14 is a perspective view of a state where a metal wire used in the present embodiment is cut.

FIG. 15 is a diagram showing a range of characteristics of a metal material suitable for adding mass to a vibrating body.

[Explanation of symbols]

 REFERENCE SIGNS LIST 12 vibrating body 13, 14 vibrating piece 22 a to 22 d, 24 a to 24 d drive electrode 26 a to 26 d, 28 a to 28 d detection electrode 40 excitation circuit 50 detection circuit 70 angular velocity calculation circuit 85 b thermosetting resin solvent 102 fine powder 114 a low melting point metal

Claims (1)

[Claims] A vibrating body, exciting means for exciting the vibrating body, vibration detecting means for detecting vibration of the vibrating body caused by Coriolis force acting when the excited vibrating body rotates, An angular velocity detecting device for detecting the angular velocity of the rotation of the vibrating body based on the vibration detected by the vibration detecting means, wherein the resonance frequency of the vibrating body is changed to a low melting point attached to the vibrating body. An angular velocity detection device characterized by being adjusted by changing the amount of a substance.