JPH0875473A - Vibration gyro device - Google Patents

Abstract

PURPOSE: To simplify the structure and manufacturing process, stabilize the quality, and reduce the cost of product by detecting an angle speed on the basis of the fluctuation of the tensile stress and compression stress caused in the longitudinal direction of a piezoelectric oscillator having a beam structure by the Coriolis force by the rotation and vibration of the oscillator. CONSTITUTION: The drive signal corresponding to the natural frequency of an oscillator 101 oscillated from a sine-wave transmitter 301 is amplified by an AC amplifier 302 and applied to electrode parts 108, 109. The electrode parts 108, 109 output signals corresponding to the deflection displacement of the oscillator 101. A differential amplifier 303 determines the signal voltage difference from the electrode parts 106, 107 as a signal corresponding to the amplitude of natural vibration of the oscillator 101. A synchronizer 304 synchronously detects the signal of the amplifier 303 and outputs the result to a divider 309. An adder 306 similarly determines the sum of the signal voltages followed by synchronous detection, and outputs the result to the divider 309. Since each speed is thus detected on the basis of the tensile and compression stresses of the oscillator 101, a simple structure, a simple manufacturing process and a stable quality can be ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration gyro device for detecting a rotational angular velocity by using a piezoelectric vibrator in which a piezoelectric element is bonded to the vibrator.

[0002]

2. Description of the Related Art As a conventional gyro device, for example, there is a vibrating gyro device or a tuning fork gyro device which detects a rotational angular velocity by using a Coriolis force acting on a beam structure oscillator. Specific examples of these vibrating gyro devices and tuning fork gyro devices include radio navigation No. 1987. Three
3, Sp.15-21 "Vibration Gyro Technology and Its Application and Future Trends", as detailed in the 1950s Sperry type tuning fork gyro device (see Fig. 11).
, A cup-type gyro device (also referred to as an annular gyro device: see FIG. 12), a Watson-type tuning fork gyro device (see FIGS. 13 (a) and 13 (b)), and a twin resonance developed for an aircraft in the 1960s. Type gyro device (see Fig. 14)
Or, various forms of the twin resonance type gyro device such as an improved and improved twin resonance type gyro device having a triangular cross-section have been developed.

These gyro devices are driving means for generating bending vibration in a specific direction of the vibrator and detecting means for detecting bending vibration corresponding to Coriolis force generated in a direction orthogonal to the bending vibration direction. In many cases, the driving means and the detecting means are constituted by a piezoelectric element bonded to the vibrator.

[0004]

However, according to the conventional gyro device described above, the bending vibration in the direction orthogonal to the bending vibration direction on the driving side is detected, and the bonding surface of the piezoelectric element to the vibrator is Since the drive side and the detection side are orthogonal or three-dimensional, the following factors cause difficulties in quality control during manufacturing, difficulties in ensuring stable quality, and increased equipment prices. There is a problem that the manufacturing process becomes complicated.

First, in order to maintain the detection accuracy and the stability of bonding, it is necessary to secure the surface accuracy of the vibrator, and the surface accuracy condition of the vibrator becomes strict. Second, in the joining process, it is necessary to join one after joining the other, so there is a time lag in the joining of the drive side and the detection side in the process, and the adhesive viscosity, coating amount, pressing load, heating conditions, etc. It is difficult to keep the bonding conditions of (1) uniform, and it is difficult to ensure the uniformity of the vibrator. Thirdly, since it is difficult to ensure the uniformity of the vibrator, the processing such as cutting off a part of the vibrator is performed in the final process,
It is necessary to adjust the natural frequency of the oscillator or adjust the sensitivity on the circuit.

Further, a biresonant gyro having a generally simple structure also requires three piezoelectric elements, that is, a piezoelectric element for driving means, a piezoelectric element for detecting drive amplitude and a piezoelectric element for detecting angular velocity. Since it is technically difficult to stably bond the piezoelectric element to the vibrator, there is also a problem that the product yield is low.

The present invention has been made in view of the above problems, and has a simple structure, a simple manufacturing process, easy quality control during manufacturing, stable quality, and inexpensive vibration. An object is to provide a gyro device.

[0008]

In order to achieve the above-mentioned object, the present invention provides a vibrating gyroscope according to claim 1, wherein a vibrating gyro device is provided with a piezoelectric vibrator joined to a vibrator and is rotated. In a vibration gyro device that detects angular velocity,
It is generated in the longitudinal direction of the piezoelectric vibrator by a piezoelectric vibrator having a symmetrical cantilever structure whose center is rotatably supported by a support column and Coriolis force by rotation and vibration of the piezoelectric vibrator. An angular velocity detecting means for detecting the angular velocity based on the fluctuations of the tensile stress and the compressive stress is provided.

In the vibrating gyro device according to a second aspect of the invention, the piezoelectric vibrator has a plate-shaped first piezoelectric element bonded to one surface of the plate-shaped vibrator and a plate-shaped piezoelectric element on the other surface. It is a structure in which a second piezoelectric element is joined, and the angular velocity detecting means is
Applying means for applying an AC drive voltage to the first piezoelectric element, and output from the second piezoelectric element according to the Coriolis force when the AC drive voltage is applied to the first piezoelectric element Detecting means for detecting a signal, control means for controlling the value of the AC drive voltage applied by the applying means based on the signal detected by the detecting means, and the signal detected by the detecting means by the applying means. An angular velocity signal output means for converting the applied AC drive voltage into a phase different from the phase of 90 degrees and outputting it as an angular velocity signal is provided.

In the vibrating gyro device according to claim 3, the vibrator is a metal plate, and the first piezoelectric element is a joint surface between the first piezoelectric element and the metal plate which is the vibrator. The electrode layer divided into two parts is joined to the surface opposite to and the sinusoidal voltage having a frequency matching the natural frequency of the vibrator is applied to the divided electrode layer. There is something.

Further, in the vibrating gyro device according to a fourth aspect, the vibrator is a metal plate, and the second piezoelectric element is a bonding surface between the second piezoelectric element and the metal plate which is the vibrator. An electrode layer divided into two is joined to a surface opposite to the one side, and the detection means outputs a first signal output from one electrode layer of the two divided electrode layers and a second signal output from the other. Is obtained, and the difference between the first signal and the second signal is synchronously detected with reference to the drive signal of the applying means.
The sum of the first signal and the second signal is obtained, the sum of the first signal and the second signal is synchronously detected with the drive signal of the applying means as a reference, and the control means uses the detection means. The value of the AC drive voltage is controlled on the basis of the difference between the first signal and the second signal which are synchronously detected, and the angular velocity signal output means is configured to detect the first signal and the second signal which are synchronously detected by the detecting means. The angular velocity signal is output based on the sum of the signals.

Further, in the vibrating gyro device according to a fifth aspect, the vibrator is a metal plate, and the second piezoelectric element is a joint surface between the second piezoelectric element and the metal plate which is the vibrator. A two-divided electrode layer is joined to a surface opposite to the first surface, and the detection means outputs from one of the two-divided electrode layers with the drive signal of the applying means as a reference. Signal is synchronously detected and the other second signal output is synchronously detected, and the angular velocity signal output means determines the output ratio of the first signal and the second signal synchronously detected by the detection means. Based on this, the angular velocity signal is output.

Further, in the vibration gyro device according to a sixth aspect, the first piezoelectric element and the second piezoelectric element are made of the same material, and are polarized in the same direction in the thickness direction over the entire surface of the vibrator. To do.

In the vibrating gyro device according to a seventh aspect, the vibrator and the piezoelectric element have the same length,
The electrode layer formed on the piezoelectric element is divided at the center of the piezoelectric element and is formed over the entire surface up to the end portion of the vibrator.

Further, in the vibrating gyro device according to the eighth aspect, the supporting column holds the central portion of the piezoelectric vibrator.

Further, in the vibration gyro device according to a ninth aspect, the piezoelectric vibrator is composed of a laminated body of a vibrator, a piezoelectric element, and an electrode layer, and the electrode layer is a central portion of the piezoelectric vibrator. The support columns are missing and sandwich the missing central portion of the electrode layer.

[0017]

A vibrating gyro device according to the present invention (claim 1)
Is a cantilever structure in which the central portion is rotatably supported by a support column and has a symmetrical structure, and the angular velocity detection means uses the Coriolis force generated by the rotation and vibration of the piezoelectric oscillator to generate the piezoelectric oscillator. By detecting the angular velocity based on the fluctuations in the tensile stress and the compressive stress generated in the longitudinal direction of the piezoelectric vibrator, the piezoelectric vibrator has a simple structure and can be manufactured by a simple manufacturing process. This also facilitates quality control during manufacturing. Furthermore, an inexpensive vibration gyro device with stable quality can be obtained.

Further, the vibrating gyro device according to the present invention (claim 2) is characterized in that the plate-shaped vibrator is provided on one surface of the plate-shaped vibrator.
, A piezoelectric vibrator having a structure in which a plate-shaped second piezoelectric element is bonded to the other surface, an applying unit, a detecting unit,
Using the angular velocity detecting means having the control means and the angular velocity signal output means, the applying means applies the AC driving voltage to the first piezoelectric element, and the detecting means applies the AC driving voltage to the first piezoelectric element. Second, depending on Coriolis force
The signal output from the piezoelectric element of
The value of the AC drive voltage applied by the application unit is controlled based on the signal detected by the detection unit, and the angular velocity signal unit controls the value of 90 relative to the phase of the AC drive voltage applied by the application unit.
The signals detected by the detection means are converted into different phases and output as an angular velocity signal.

Further, in the vibrating gyro device according to the present invention (claim 3), a divided electrode layer is bonded to the surface opposite to the bonding surface between the first piezoelectric element and the metal plate which is the vibrator. By using the first piezoelectric element having the above structure, a sine wave voltage having a frequency matching the natural frequency of the vibrator is applied to the two-divided electrode layers of the first piezoelectric element.

Further, in the vibrating gyro device according to the present invention (claim 4), a divided electrode layer is bonded to the surface opposite to the bonding surface between the second piezoelectric element and the metal plate which is the vibrator. Using the second piezoelectric element having the above structure, the detecting means obtains the difference between the first signal output from one of the two electrode layers and the second signal output from the other electrode layer, and applies the difference. Means for synchronously detecting the difference between the first signal and the second signal with reference to the drive signal of the means, and further obtaining the sum of the first signal and the second signal. And the second
The synchronous detection of the sum of the signals of No. 1, and the control means controls the value of the AC drive voltage based on the difference between the first signal and the second signal synchronously detected by the detection means, and the angular velocity signal output means The angular velocity signal is output based on the sum of the first signal and the second signal that are synchronously detected by the detection means.

Further, in the vibrating gyro device according to the present invention (claim 5), the divided electrode layer is bonded to the surface opposite to the bonding surface between the second piezoelectric element and the metal plate which is the vibrator. Using the second piezoelectric element having the above configuration, the detection means synchronously detects the first signal output from one of the two electrode layers divided by the drive signal of the application means, and the other Of the output second signal is synchronously detected, and the angular velocity signal output means outputs the angular velocity signal based on the output ratio of the first signal and the second signal synchronously detected by the detection means.

The vibrating gyro device according to the present invention (claim 6) is made of the same material, and the first piezoelectric element and the second piezoelectric element which are polarized in the same direction in the thickness direction over the entire surface of the vibrator, respectively. A piezoelectric element is used.

Further, a vibrating gyro device according to the present invention (claim 7) uses a vibrator and a piezoelectric element having the same length, and further, an electrode layer formed on the piezoelectric element has a central portion of the piezoelectric element. It is divided by and is formed over the entire surface up to the end of the vibrator.

Further, in the vibrating gyro device according to the present invention (claim 8), the central portion of the piezoelectric vibrator is sandwiched by the supporting columns.

Further, in the vibrating gyro device according to the present invention (claim 9), the piezoelectric vibrator is composed of a laminated body of a vibrator, a piezoelectric element and an electrode layer, and the electrode layer is a piezoelectric vibrator. The central part is missing, and the central part where the electrode layer is missing is sandwiched between the supporting columns.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vibrating gyro device of the present invention will be described below in detail in the order of [Embodiment 1], [Embodiment 2], [Embodiment 3], [Embodiment 4] with reference to the drawings.

[Embodiment 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a piezoelectric vibrator 100 in a vibrating gyro device according to a first embodiment. As illustrated, the piezoelectric vibrator 100 according to the first embodiment uses a constant elastic metal or the like to suppress a change in natural frequency due to temperature, and has a plate-shaped vibrator 101 and a vibrator 101.
Piezoelectric elements 104 and 105 bonded to both surfaces of the
And the electrode portion 10 bonded to the surface of the piezoelectric element 104 opposite to the surface of the piezoelectric element 104 bonded to the vibrator 101.
6 and 107, and electrode portions 108 and 109 bonded to the surface of the piezoelectric element 105 opposite to the surface of the piezoelectric element 105 bonded to the vibrator 101.

In the figure, 102 is a vibrator 10
1 is a support column made of a metal material that is joined to the central portion of 1 to rotatably support the vibrator 101, and 103 is a pedestal part made of an insulating material that fixes the support column 102.
Reference numerals 0 to 113 denote terminals connected to the electrode portions 106 to 109.

Further, the vibrator 101 is divided into left and right by a support column 102, and both the left and right of the divided vibrator 101 have a cantilever structure, and further, each cantilever structure is completely equivalent as a vibrator. Has been formed.

Generally, the natural frequency of a vibrator is determined by the shape of the vibrator. Therefore, in the vibration gyro device, the natural frequency of the vibrator is set by changing the shape of the vibrator according to the required responsiveness and the angular velocity range to be detected. In the first embodiment, in the above structure, the natural frequency of the vibrator 101 is set by changing the thickness of the vibrator 101 and the length of the vibrator 101. That is, it is possible to set the natural frequency of the vibrator according to various requirements by changing only the plate-shaped vibrator 101 while keeping many components common, and to meet various requirements. The vibration gyro device can be easily provided.

Next, referring to FIG. 2, the piezoelectric element 104,
The polarization direction of 105 will be described. In the first embodiment, 104a indicates the polarization direction of the piezoelectric element 104,
Reference numeral 05a indicates the polarization direction of the piezoelectric element 105. here,
Polarization directions 104a and 105a of the piezoelectric elements 104 and 105
Are in the same direction over the entire surface in the thickness direction of the piezoelectric elements 104, 105. The polarization directions 104a and 105a
Shows the case where the piezoelectric elements 104 and 105 are opposite to the direction in which the vibrator 101 is bonded, but the polarization direction may be the same direction as the direction in which the piezoelectric elements 104 and 105 and the vibrator 101 are bonded. Of course.

Since the electrodes 106 to 109 are bonded to the surfaces of the piezoelectric elements 104 and 105 so as to be bilaterally symmetric (horizontal equivalent) with respect to the center of the vibrator 101, the positional accuracy can be easily controlled. At the same time, it becomes possible to assemble while considering the homogenization of the joining conditions. Furthermore, the piezoelectric elements 104 and 105 and the vibrator 101 can be joined by stacking plate-like members in the same direction in a single plane and assembling them, so that the automation of the assembly becomes extremely easy.

Next, the configuration of the detection circuit of the vibration gyro device of the first embodiment will be described with reference to FIG. In addition,
The detection circuit (angular velocity detection means of the present invention) is roughly divided into three systems of a drive system, a detection system and a calculation system.

The drive system inputs a drive signal from a sine wave oscillator 301 which oscillates a sine wave signal corresponding to the natural frequency of the vibrator 101 as a drive signal, and a drive signal from the sine wave oscillator 301, and an electrode based on the drive signal. AC amplifier 302 with automatic gain adjustment function for applying voltage to parts 108 and 109
And a differential amplifier 303 that obtains a difference between the voltages (or charges) output from the electrode units 106 and 107 and outputs a signal corresponding to the amplitude of vibration of the vibrator 101, and a drive signal from the sine wave oscillator 301. And a first phase adjuster 305 that generates a first synchronization timing signal based on the drive signal, and a differential increase based on the first synchronization timing signal of the first phase adjuster 305. It is composed of a first synchronous rectifier 304 that synchronously detects the signal input from the amplifier 303. As shown in the drawing, the signal output from the first synchronous rectifier 304 is fed back to the AC amplifier 302 with the automatic gain adjusting function, and the output level of the signal output from the first synchronous rectifier 304 is constant. Therefore, the voltage level of the drive signal described above is automatically adjusted.

Further, the detection system obtains the sum of the voltages (or charges) output from the electrode portions 106 and 107 and obtains a signal corresponding to the angular velocity produced by the oscillator 101.
06, a second synchronous rectifier 307 that synchronously detects a signal output from the adder 306 based on a second synchronous timing signal described later, and a first synchronous timing signal from the first phase adjuster 305. , A second phase adjuster 308 which outputs a second synchronization timing signal whose phase is 90 degrees different from that of the first synchronization timing signal.

Further, the calculation system is the first synchronous rectifier 30.
A divider 309 that outputs a signal in which the temperature characteristics and the sensitivity deterioration of the piezoelectric element are corrected by calculating the output ratio of the signal output by the fourth phase adjuster 308 and the signal output by the second phase adjuster 308.
Consists of

The operation of the above configuration will be described. The drive signal corresponding to the natural frequency of the oscillator 101 transmitted from the sine wave oscillator 301 is amplified by the AC amplifier 302 and applied to the electrode units 108 and 109. When a drive signal is applied, the electrode portions 106 and 107 are provided with the vibrator 1
A signal corresponding to the flexural displacement of 01 is output.

The differential amplifier 303 includes electrode parts 106, 10
The voltage difference between the signals output from 7 is obtained as a signal corresponding to the amplitude of the natural vibration of the vibrator 101. The first synchronous rectifier 304 uses the drive signal as a reference, and the differential amplifier 30
The signal input from 3 is subjected to synchronous detection by the first synchronous timing signal obtained by the first phase adjuster 305 and output to the divider 309.

On the other hand, the adder 306 includes the electrode units 106, 1
The sum of the voltages of the signals output from 07 is obtained as a signal corresponding to the Coriolis force of the vibrator 101. The second phase adjuster 308 provides the second synchronous rectifier 307 with a second synchronous timing signal that is 90 degrees out of phase with the first synchronous timing signal obtained by the first phase adjuster 305. The second synchronous rectifier 307 performs synchronous detection on the signal output from the adder 306 with the second synchronous timing signal obtained by the second phase adjuster 308, and outputs the signal to the divider 309.

The divider 309 is the first synchronous rectifier 30.
The output ratio of the signal output from the signal No. 4 and the signal output from the second phase adjuster 308 is calculated. Specifically, for example, when the synchronization timing of the first synchronous rectifier 304 is A and the synchronization timing of the second synchronous rectifier 307 is B, the output ratio C can be obtained as follows. C = B / A

Next, referring to FIGS. 4A and 4B, the piezoelectric vibrator 100 in the case where the angular velocity is not applied
The operating state of will be specifically described. Figure 4 (a) shows
The state where the voltage of the drive signal is applied to the piezoelectric vibrator 100 with the maximum amplitude is shown. In the state where the positive (positive) charge is applied to the electrode portion 108 and the negative (negative) charge is applied to the electrode portion 109, the piezoelectric element 105 causes the support column 102 to be sandwiched between the piezoelectric element 105 and the piezoelectric element 105, and the piezoelectric element 105 bends in the opposite directions. Here, since the polarization direction of the piezoelectric element 105 and the polarity of the applied charge are opposite, when the right side portion of the piezoelectric element 105 to which the electrode portion 108 is joined extends, the piezoelectric element 105 to which the electrode portion 109 is joined. The left side of the will shrink. On the other hand, in the piezoelectric element 104, the right side portion is warped in the electrode portion 106 direction, and the left side portion is warped in the vibrator 101 direction.

Here, the relationship between the tensile stress and the compressive stress generated in the longitudinal direction of the piezoelectric vibrator 100 will be described by mathematical expressions. Since the vibrator 101 has the same potential, the piezoelectric element 1
A negative voltage is generated in the electrode portion 106 joined to the right half of 04. The voltage of the electrode portion 106 is V1, the generated charge is Q,
When the capacitance of the piezoelectric element is C, a voltage V1 corresponding to V1 = -Q / C is generated. In addition, the piezoelectric element 104
Assuming that the positive voltage of the electrode portion 107 joined to the left half of V is V2, V2 = -V1 V2 =-(-Q / C) V2 = Q / C occurs.

The difference (differential output) between the voltage V1 of the electrode portion 106 and the voltage V2 of the electrode portion 107 is V1-V2 = -Q / C-Q / C = -2Q / C, and the voltage of the electrode portion 106 is The sum of V1 and the voltage V2 of the electrode portion 107 is V1 + V2 = -Q / C + Q / C = 0. Here, the voltage V1 of the electrode portion 106 and the electrode portion 10
The difference in the voltage V2 of 7 corresponds to the maximum amount of deflection in the vibrator 101.

FIG. 4B shows the piezoelectric vibrator 1 of FIG.
This is a state in which the phase of the drive signal is shifted by 180 degrees with respect to the state in which the voltage of the drive signal is applied to 00 with the maximum amplitude. Contrary to FIG. 4A, tensile stress acts on the right half and compressive stress acts on the left half in the longitudinal direction of the oscillator 101. At this time, the voltage V1 of the electrode portion 106 and the voltage V1 of the electrode portion 107
The difference of 2 (differential output) is V1-V2 = Q / C-(-Q / C) = 2Q / C, and the sum of the voltage V1 of the electrode portion 106 and the voltage V2 of the electrode portion 107 is V1 + V2 = Q / C + (-Q / C) = 0.

Therefore, the oscillator 101 is not supported by the support pillar 102.
In the condition that the angular velocity with
Electrode portion 106 bonded to the piezoelectric element 105 on the detection system side
Differential output voltage (charge) generated between the electrode and the electrode 107
Is an AC output corresponding to the maximum bending deflection amount of the oscillator 101 in substantially the same phase as the drive voltage output from the sine wave oscillator 301, and the sum thereof is zero voltage.

Next, referring to the oscillator model of FIG. 5, the vibration state and the stress generation state when the angular velocity acts on the oscillator will be described. FIG. 5A shows a vibrator model in a state where no angular velocity is applied to the vibrator. This oscillator model is arranged such that a mass point 501 and a mass point 502 corresponding to the mass point m of the center of gravity of the oscillators arranged symmetrically, a spring 503 connecting the two mass points 501 and 502, and a position above and below the mass point 501. , The springs 504 and 505 that hang the mass 501, and the mass 50 located above and below the mass 502.
1 springs 506 and 507 and mass points 501 and 5
02, springs 503 to 507 are accommodated, and springs 504 to 50
7 and a box 508 for holding the mass points 501 and 502 so that they can move freely. Here, it is assumed that the oscillator is formed by the mass points 501 and 502 and the spring 503, and the longitudinal direction of the spring 503 is the longitudinal direction of the oscillator.

The mass point 501 and the mass point 502 are respectively located in the center of the box 508 with respect to the vertical direction.
4, 505 and springs 506, 507 hang. The constants of the springs 504, 505, 506 and 507 are set to the same predetermined constant.

In the figure, when vibration is applied to the mass point 501, the mass point 501 and the mass point 502 vibrate in opposite directions with respect to the vertical direction. At this time, mass point 501 and mass point 50
No. 2 vibrates in the vertical and reverse directions, but at the neutral position (the position where the vibration speed is maximum at the zero amplitude position), the external force acts in the longitudinal direction of the oscillator (that is, the action on the spring 503).
Does not occur.

FIG. 5B shows the operation when the angular velocity Ω is applied together with the vibration. When the angular velocity Ω is added,
Coriolis force F = 2 mV at the neutral position on the right mass point 501
Ω (where V is the vibration velocity at the neutral position) acts.
In addition, a mass point 501 and a mass point 502 are provided on the left mass point 502.
Have the same mass m and opposite velocity vectors,
Coriolis force F = -2 mVΩ acts at the neutral position.

That is, when the angular velocity Ω is applied, a compressive stress acts on the central portion (spring 503) of the vibrator as a combined force of the Coriolis force on the left and right mass points 501 and 502.

On the other hand, as shown in FIG.
In the phase at the timing 180 degrees out of phase with the vibration in (b), even at the same neutral position, the mass points 501, 502
5 is in the opposite direction to the case of FIG. 5 (b), the Coriolis force acting on each mass point 501, 502 is also shown in FIG.
In the opposite direction to (b), the center of the oscillator (spring 50
Tensile stress acts on 3).

That is, when the angular velocity about the support column of the vibrator acts on the vibrator, the drive voltage has the maximum amplitude at the neutral point of zero. In other words, an AC expansion / contraction stress whose phase is delayed by 90 degrees with respect to the phase of the drive voltage is generated in the longitudinal direction of the vibrator.

When the angular velocity Ω shown in FIGS. 5 (b) and 5 (c) is rotated in the opposite direction, that is, when the angular velocity is −Ω, as shown in FIGS. 6 (a) and 6 (b). And the mass point 501
Since the Coriolis force is in the opposite direction with respect to the same velocity direction of the mass point 502, the phase is delayed by 180 degrees in FIGS. 6A and 6B as compared with the case of FIGS. 5B and 5C. Stretching stress (inverted) will act. Therefore,
Also in this case, an AC expansion and contraction stress whose phase is delayed by 90 degrees with respect to the phase of the drive voltage is generated in the longitudinal direction of the vibrator.

Next, the operation of the detection system will be described with reference to FIGS. 4A and 4B, based on the principle of stress generation by the above-described oscillator model. Detection system electrode section 106,
Looking at the generated voltage (charge) of the electrode portion 107, FIG.
4B, in the middle of the stage where the bending of the vibrator 101 is zero and the neutral position, only the stretching force due to the Coriolis force acts on the left and right sides of the vibrator 101 in common, so that the electrode portion 106 and the electrode portion 107 The output difference becomes zero, and the sum of the outputs of the electrode portion 106 and the electrode portion 107 becomes a positive or negative voltage according to the expansion / contraction force.

Therefore, as shown in FIG. 7A, the output of the differential amplifier 303 is synchronously detected and rectified with the drive signal as a reference to obtain a DC voltage corresponding to the vibration amplitude of the vibrator 101. To be Further, the second synchronization timing signal output from the second phase adjuster 308 is a signal having a phase difference of 90 degrees from the first synchronization timing output from the first phase adjuster 305, and further, the second Synchronous rectifier 3
At 07, by synchronously detecting and rectifying the signal obtained by the adder 306 with the second synchronous timing signal from the second phase adjuster 308, as shown in FIG. Positive and negative DC voltages corresponding to the rotational direction of the angular velocity about the reference voltage can be obtained.

As described above, in the first embodiment, the oscillator 1
The level of the drive voltage is controlled by the AC amplifier 302 with the automatic gain adjusting function so that the DC voltage corresponding to the vibration amplitude of 01 becomes constant, and the DC voltage corresponding to the angular velocity is set to the vibration amplitude of the vibrator 101. By dividing by the corresponding DC voltage, it is possible to cancel the sensitivity change due to the deterioration of the piezoelectric element and the temperature change, so that it is possible to provide a vibration gyro device that can detect the angular velocity extremely stably.

Further, according to the first embodiment, in the drive system and the detection system attached to the left and right vibrators, which are important for ensuring the performance of the vibration gyro device, from the viewpoint of the left and right uniformity, the drive system is also used. Piezoelectric element 104 and piezoelectric element 105 for detection
Since each is a single piezoelectric element, and the process of forming electrodes can be performed simultaneously for driving and detection,
An extremely high homogeneity can be assured on the left and right sides of the vibrator 101 centered around 2.

Further, the vibrator 101 and the piezoelectric elements 104, 1
The connection with 05 is suitable for automating the bonding process because they can be stacked in one direction. Furthermore, the left and right bonding processes are simultaneous processes, and the vibrator 10
Since the left and right homogeneity of the vibrator 101 can be easily ensured only by controlling the alignment accuracy between the piezoelectric element 104 and the piezoelectric elements 104 and 105, the drive system and the detection system are separated from each other like the vibrator in the conventional three-dimensional structure. Since it is not necessary to adjust the natural frequency and the left-right balance of the oscillator by cutting the oscillator,
An inexpensive and high-performance vibrating gyro device can be realized.

In the first embodiment, the vibrator 101 is made of a metal material, the piezoelectric vibrator 100 is composed of a thick metal plate as the vibrator 101, and thin piezoelectric elements 104 and 105 are partially bonded to the central portion. However, the present invention is not limited to this.

[Embodiment 2] In Embodiment 2, in the piezoelectric vibrator, the width and length of the piezoelectric element are the same as those of the metal plate which is the vibrator. The basic structure is the same as that of the first embodiment.
In this case, only different parts will be explained here.

FIG. 8 shows the structure of the piezoelectric vibrator 800 according to the second embodiment, in which the width and length of the piezoelectric elements 802 and 803 are set to the vibrator 8.
The vibrator 801 and the piezoelectric elements 802 and 803 are bonded to each other with the same metal plate as 01. Next, the electrode parts 804-8
07 is bonded to the piezoelectric elements 802 and 803 so that the electrode portion is missing at the central portion as shown in the drawing.

In the piezoelectric vibrator 800, the vibrator 801
If the structure is bilaterally symmetric with respect to the central part, a predetermined performance can be obtained as the vibration gyro device. Therefore,
In the second embodiment, for example, when the vibrator 801 is a metal plate having a relatively large area, the piezoelectric elements 802 and 803 having the same area are joined and then the piezoelectric element 80
After bonding the electrode layer to the entire surface of 2,803, cut only the electrode layer at the central position with a diamond saw or cut it by an electrochemical treatment such as etching, and then use a diamond saw or the like to give a predetermined width and length. Piezoelectric vibrator with
The feature is that many can be cut out and created. Therefore, according to the configuration of the piezoelectric vibrator 800 of the second embodiment,
It is possible to mass-produce piezoelectric resonators that are all homogeneous.

[Third Embodiment] The basic structure of the third embodiment is common to that of the first embodiment, and only different parts will be described here. In the third embodiment, the structure of the supporting column is different and the structure of the supporting column and its effect will be described with reference to FIG.

FIG. 9 shows the structure of the piezoelectric vibrator 900 of the third embodiment, and the support column 901 has a structure in which the center of the vibrator 902 is sandwiched. The support columns 901 are piezoelectric elements 903, 90.
The vibrator 902 and the piezoelectric elements 903 and 904 are sandwiched from both sides in a portion where the electrode portions 905 to 908 bonded to the No. 4 do not exist. In the second embodiment, as compared with the first embodiment, the structure of the support column 901 can be robustly formed regardless of the thickness of the vibrator 902. Therefore, the fixed end of the cantilever structure in the vibrator 902 becomes clear, stable vibration of the vibrator 902 is possible, and even if the thickness of the vibrator 902 is thin, the angular velocity can be detected stably.

[Fourth Embodiment] In the fourth embodiment, similarly to the third embodiment, a support column for sandwiching a vibrator is used. Also,
In Examples 1 to 3, a metal plate was used for the vibrator, but in Example 4, an electrode layer was used for the vibrator. Here, the difference from the first to third embodiments is only that an electrode layer is used for the vibrator, and the other configurations are common, and the description is omitted.

FIG. 10 shows a piezoelectric vibrator 1000 according to the fourth embodiment.
In the same manner as in the third embodiment, the vibrator 1001 including the electrode layer is arranged, and the vibrator 1001 is supported by the support column 1004.
1 and the piezoelectric elements 1002 and 1003 are sandwiched from both sides. The electrode layer which is the vibrator 1001 is grounded as a neutral point potential. By using the electrode layer for the vibrator 1001, the step of joining the metal plate (vibrator) and the piezoelectric element becomes unnecessary. The electrode layer that is the vibrator 1001 and the piezoelectric element 1002
The manufacturing process with 1003 is the same as the manufacturing process of the multilayer capacitor, for example, by laminating with a green sheet,
Since it can be cut after sintering, it has higher mass productivity than the case where a metal plate is used for the vibrator.

[0066]

As described above, in the vibrating gyro device of the present invention (claim 1), the piezoelectric vibrator is structured as a bilaterally symmetric cantilever structure in which the central portion is rotatably supported by the supporting column. However, the angular velocity detection means detects the angular velocity based on the fluctuations of the tensile stress and the compressive stress generated in the longitudinal direction of the piezoelectric vibrator by the Coriolis force due to the rotation and vibration of the piezoelectric vibrator, so that the simple structure It is possible to provide a vibrating gyro device that is simple in quality, easy in quality control during manufacturing, stable in quality, and inexpensive in manufacturing process.

Further, in the vibrating gyro device of the present invention (claim 2), the plate-shaped first piezoelectric element is bonded to one surface of the plate-shaped vibrator, and the plate-shaped second piezoelectric element is bonded to the other surface. An AC drive voltage is applied to the first piezoelectric element by the applying means by using the piezoelectric vibrator having a structure in which the piezoelectric elements are joined and the angular velocity detecting means including the applying means, the detecting means, the controlling means and the angular velocity signal outputting means. Then, when the AC drive voltage is applied to the first piezoelectric element by the detection means, the signal output from the second piezoelectric element according to the Coriolis force is detected, and by the control means, it is detected by the detection means. The value of the AC drive voltage applied by the applying means is controlled based on the signal, and the signal detected by the detecting means in the angular velocity signal means in a phase different by 90 degrees from the phase of the AC drive voltage applied in the applying means. It is converted and output as an angular velocity signal. , With a simple structure, a simple manufacturing process, easy quality control during production with stable quality, and it is possible to provide an inexpensive vibration gyro device.

Further, in the vibrating gyro device of the present invention (claim 3), the divided electrode layer is bonded to the surface opposite to the bonding surface between the first piezoelectric element and the metal plate which is the vibrator. Using the first piezoelectric element having the configuration, a sinusoidal voltage having a frequency matching the natural frequency of the vibrator is applied to the two-divided electrode layers of the first piezoelectric element. In the drive system and the detection system attached to the left and right vibrators, which are important for ensuring the performance, the drive piezoelectric element and the detection piezoelectric element each have 1 even from the viewpoint of the left and right uniformity.
Since it is a single piezoelectric element and the process of forming electrodes can be performed simultaneously for driving and detection, extremely high homogeneity can be guaranteed on the left and right sides of the vibrator centered on the support column.

Further, in the vibrating gyro device of the present invention (claim 4), a divided electrode layer is bonded to the surface opposite to the bonding surface between the second piezoelectric element and the metal plate which is the vibrator. By using the second piezoelectric element having the configuration, the detecting means obtains the difference between the first signal output from one of the two electrode layers and the second signal output from the other electrode layer, and the applying means Of the first signal and the second signal are synchronously detected with reference to the drive signal of No. 1, and the sum of the first signal and the second signal is obtained. The sum of the second signals is synchronously detected, and the control means controls the value of the AC drive voltage based on the difference between the first signal and the second signal which are synchronously detected by the detecting means, and outputs the angular velocity signal. Means outputs an angular velocity signal based on the sum of the first signal and the second signal synchronously detected by the detection means. Therefore, the drive voltage level is controlled by the AC amplifier with the automatic gain adjustment function so that the DC voltage corresponding to the vibration amplitude of the vibrator becomes constant, and the DC voltage corresponding to the angular velocity is vibrated. By dividing by the DC voltage corresponding to the amplitude, it is possible to cancel the sensitivity change due to the deterioration of the piezoelectric element and the temperature change, so that it is possible to provide a vibration gyro device that can detect the angular velocity extremely stably.

Further, in the vibrating gyro device according to the present invention (claim 5), the divided electrode layer is bonded to the surface opposite to the bonding surface between the second piezoelectric element and the metal plate which is the vibrator. Using the second piezoelectric element having the above configuration, the detection means synchronously detects the first signal output from one of the two electrode layers divided by the drive signal of the application means, and the other Is detected synchronously, and the angular velocity signal output means outputs the angular velocity signal based on the output ratio of the first signal and the second signal synchronously detected by the detection means. It is possible to provide a vibration gyro device capable of canceling sensitivity change due to element deterioration and temperature change and capable of detecting angular velocity extremely stably.

The vibrating gyro device according to the present invention (claim 6) is made of the same material, and the first piezoelectric element and the second piezoelectric element which are polarized in the same direction in the thickness direction over the entire surface of the vibrator, respectively. Since a piezoelectric element is used, it is possible to mass-produce an all-homogeneous piezoelectric vibrator.

Further, the vibrating gyro device according to the present invention (claim 7) uses the vibrator and the piezoelectric element having the same length, and the electrode layer formed on the piezoelectric element has a central portion of the piezoelectric element. Since it is divided by and is formed over the entire surface to the end of the vibrator, it is possible to mass-produce piezoelectric vibrators that are all homogeneous.

Further, in the vibrating gyro device according to the present invention (claim 8), since the central portion of the piezoelectric vibrator is sandwiched between the supporting columns, the structure of the supporting column can be robustly formed regardless of the thickness of the oscillator. , The fixed end of the cantilever structure in the vibrator becomes clear and stable vibration of the vibrator is possible, so that the angular velocity can be detected stably even when the thickness of the vibrator is thin.

In the vibrating gyro device according to the present invention (claim 9), the piezoelectric vibrator is composed of a laminate of a vibrator, a piezoelectric element and an electrode layer, and the electrode layer is a piezoelectric vibrator. Since the central part where the electrode layer is missing is sandwiched between the supporting pillars because the electrode part is sandwiched between the supporting pillars, the electrode layer is used for the vibrator, which eliminates the need to join the metal plate (vibrator) and the piezoelectric element The process of manufacturing the electrode layer and the piezoelectric element, which are the children, can be performed in the same manner as the process of manufacturing the multilayer capacitor.
It is possible to make mass production even higher than when using a metal plate for the oscillator.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a piezoelectric vibrator in a vibrating gyro device according to a first embodiment.

2A and 2B are diagrams for explaining polarization directions of the piezoelectric element in Example 1. FIG.

FIG. 3 is an explanatory diagram showing a configuration of a detection circuit of the vibration gyro device of the first embodiment.

FIG. 4 is an explanatory diagram showing an operating state of the piezoelectric vibrator in the first embodiment when no angular acceleration is applied.

FIG. 5 is an explanatory diagram showing a vibration state and a stress generation state when an angular velocity (Ω) acts on the vibrator.

FIG. 6 is an explanatory diagram showing a vibration state and a stress generation state when an angular velocity (−Ω) acts on the vibrator.

FIG. 7 is an explanatory diagram showing a synchronous detection output in the first embodiment.

FIG. 8 is an explanatory diagram showing a structure of a piezoelectric vibrator of Example 2.

FIG. 9 is an explanatory diagram showing a configuration of a piezoelectric vibrator of Example 3.

FIG. 10 is an explanatory diagram showing a configuration of a piezoelectric vibrator of Example 4.

FIG. 11 is an explanatory diagram showing a conventional Sperry type tuning fork gyro device.

FIG. 12 is an explanatory diagram showing a conventional cup-type gyro device.

FIG. 13 is an explanatory diagram showing a conventional Watson-type tuning fork gyro device.

FIG. 14 is an explanatory diagram showing a conventional twin resonance type gyro device.

[Explanation of symbols]

100 piezoelectric vibrator 101 vibrator 102 support pillar 103 pedestal part 104, 105 piezoelectric element 106, 107, 108, 109 electrode part 110, 111, 112, 113 terminal 301 sine wave oscillator 302 AC thickener 303 differential thickener 304 First Synchronous Rectifier 305 First Phase Adjuster 306 Adder 307 Second Synchronous Rectifier 308 Second Phase Adjuster 309 Divider 800 Piezoelectric Oscillator 900 Piezoelectric Oscillator 901 Support Pillar 1000 Piezoelectric Oscillator 1001 Oscillator

Claims (9)

[Claims] 1. A vibrating gyro device for detecting a rotational angular velocity using a piezoelectric vibrator in which a piezoelectric element is bonded to a vibrator, wherein a central portion is rotatably supported by a support column and a symmetrical cantilever beam is provided. A piezoelectric vibrator having a structure, and an angular velocity detecting means for detecting an angular velocity based on fluctuations in tensile stress and compressive stress generated in the longitudinal direction of the piezoelectric oscillator by Coriolis force caused by rotation and vibration of the piezoelectric oscillator. A vibrating gyro device comprising: 2. The piezoelectric vibrator has a structure in which a plate-shaped first piezoelectric element is bonded to one surface of a plate-shaped vibrator and a plate-shaped second piezoelectric element is bonded to the other surface. The angular velocity detecting means includes an applying means for applying an AC drive voltage to the first piezoelectric element, and a first means according to the Coriolis force when the AC drive voltage is applied to the first piezoelectric element. Detecting means for detecting a signal output from the piezoelectric element, control means for controlling the value of the AC drive voltage applied by the applying means on the basis of the signal detected by the detecting means, and detecting means for the detecting means. 2. The vibration according to claim 1, further comprising: an angular velocity signal output unit that converts the generated signal into a phase different from the phase of the AC drive voltage applied by the applying unit by 90 degrees and outputs the phase as an angular velocity signal. Gyro device. 3. The vibrator is a metal plate, and the first piezoelectric element is divided into two parts on a surface opposite to a joint surface between the first piezoelectric element and the metal plate which is the vibrator. The electrode layers are joined, and a sinusoidal voltage having a frequency matching the natural frequency of the vibrator is applied to the two-divided electrode layers. Two
The described vibration gyro device. 4. The vibrator is a metal plate, and the second piezoelectric element is divided into two parts on the surface opposite to the joint surface between the second piezoelectric element and the metal plate which is the vibrator. The electrode layers are joined, and the detection means obtains a difference between a first signal output from one electrode layer of the two divided electrode layers and a second signal output from the other electrode layer, and the application means The synchronous detection of the difference between the first signal and the second signal with reference to the drive signal of No. 1, the sum of the first signal and the second signal is obtained, and the first with reference to the drive signal of the applying unit. Signal and second
Synchronously detecting the sum of the signals of, and the control means controls the value of the AC drive voltage based on the difference between the first signal and the second signal synchronously detected by the detection means, and outputs the angular velocity signal. The vibrating gyro device according to claim 2, wherein the means outputs the angular velocity signal based on a sum of the first signal and the second signal synchronously detected by the detecting means. 5. The vibrator is a metal plate, and the second piezoelectric element is divided into two parts on a surface opposite to a joining surface between the second piezoelectric element and the metal plate which is the vibrator. The electrode layers are joined, and the detection means synchronously detects the first signal output from one of the two divided electrode layers with the drive signal of the application means as a reference, and detects the other signal. Synchronously detecting the output second signal, and the angular velocity signal output means outputs the angular velocity signal based on an output ratio of the first signal and the second signal synchronously detected by the detection means. The vibrating gyro device according to claim 2, wherein: 6. The first piezoelectric element and the second piezoelectric element are made of the same material, and are polarized in the same direction in the thickness direction over the entire surface of the vibrator. The vibrating gyro device according to 3, 4, or 5. 7. The vibrator and the piezoelectric element have the same length, and an electrode layer formed on the piezoelectric element is divided at the center of the piezoelectric element and extends to the end portion of the vibrator. The vibrating gyro device according to claim 2, wherein the vibrating gyro device is formed over the entire surface. 8. The vibrating gyro device according to claim 1, wherein the support column holds the central portion of the piezoelectric vibrator. 9. The piezoelectric vibrator is composed of a laminated body of a vibrator, a piezoelectric element, and an electrode layer, the electrode layer is missing in a central portion of the piezoelectric vibrator, and the support column is 9. The vibrating gyro device according to claim 7, wherein a central portion of the electrode layer that is missing is sandwiched.