JP2000258164A - Oscillation gyro - Google Patents

Abstract

PROBLEM TO BE SOLVED: To support an oscillator at a high strength, without damping its oscillation. SOLUTION: A oscillation gyro 10 includes two tuning fork type oscillators 12a, 12b. Both oscillators 12a, 12b extend from one end of a base 24 and are integrated with the base 24. At both sides of the oscillators 12a, 12b two twist- preventing square pole-like arms 34a, 34b extend from both lateral ends of the base 24 and are integrated with the base 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating gyroscope, and more particularly, to a tuning fork type vibrating gyroscope used for, for example, camera shake prevention and car navigation systems.

[0002]

2. Description of the Related Art FIG. 9 is a perspective view showing an example of a conventional vibrating gyroscope. The vibrating gyroscope 1 shown in FIG. 9 includes two vibrators 2a and 2b of a sound piece type. The vibrators 2a and 2b each include a regular quadrangular prism-shaped vibrating body 3, and the vibrating body 3 includes a strip-shaped first piezoelectric substrate 3a and a second piezoelectric substrate 3b. The first piezoelectric substrate 3a and the second
Are laminated and bonded. Also, the first
The piezoelectric substrate 3a and the second piezoelectric substrate 3b are polarized in thickness directions opposite to each other. Two driving electrodes 4a and 4b are formed on the main surface of the first piezoelectric substrate 3a at intervals in the width direction thereof. Further, a detection electrode 5 is formed on the main surface of the second piezoelectric substrate 3b. In addition,
An intermediate electrode 6 is formed between the first piezoelectric substrate 3a and the second piezoelectric substrate 3b. These vibrators 2a and 2b extend from the base 7 and are formed integrally with the base 7. The driving electrodes 4a and 4b of the vibrators 2a and 2b are formed so as to extend over the upper surface of the base 7, and the vibrators 2a and 2b
Is connected to the driving electrode 4a of the vibrator 2b. Further, the two detection electrodes 5 of the vibrators 2 a and 2 b are formed to extend on the lower surface of the base 7.

[0003] In a vibrating gyroscope 1 shown in FIG. 9, an oscillation circuit 8 is connected between driving electrodes 4a and 4b of vibrators 2a and 2b as shown in FIG. This oscillation circuit 8
Includes, for example, an amplifier circuit and a phase correction circuit. Also,
The two detection electrodes 5 of the transducers 2a and 2b are connected to two input terminals of the differential circuit 9a, respectively. An output terminal of the differential circuit 9a is connected to an input terminal of the synchronous detection circuit 9b. Another output terminal of the oscillation circuit 8 is connected to another input terminal of the synchronous detection circuit 9b. An output terminal of the synchronous detection circuit 9b is connected to an input terminal of the integration circuit 9c. Integration circuit 9c
Is connected to the input terminal of the DC amplification circuit 9d.

In the vibrating gyroscope 1, an electric field is applied to the two vibrators 2a and 2b in a direction perpendicular to the polarization direction by the oscillation circuit 8, and the two vibrators 2a and 2b
b vibrates such that their tips open and close as indicated by the arrows in FIG. At this time, 2
Since the tips of the two vibrators 2a and 2b vibrate in the same state with respect to the polarization direction, the two vibrators 2a and 2b
The same output signal is obtained from the detecting electrode 5 of FIG. Therefore, a signal of 0 is output from the differential circuit 9a. In this state, when the rotational angular velocity ω is applied about the central axis O (FIG. 12) of the vibrating gyroscope 1, the two vibrators 2a and 2b receive the vibration during non-rotation as shown by the arrows in FIG. Coriolis force acts in orthogonal directions. Due to this Coriolis force, the vibration directions of the vibrators 2a and 2b are changed.
A signal corresponding to the Coriolis force is output from the detection electrodes 5 of the two transducers 2a and 2b. At this time, since the Coriolis force acts on the two vibrators 2a and 2b in opposite directions, the two vibrators 2a and 2b are displaced in opposite directions. Therefore, the two vibrators 2a and 2
The signals output from the detection electrode 5b are signals having phases opposite to each other. Therefore, if a difference between the output signals of the two detection electrodes 5 is obtained by the differential circuit 9a, a large signal corresponding to the Coriolis force can be obtained. Note that the differential circuit 9a
Is detected by the synchronous detection circuit 9b in synchronization with the signal of the oscillation circuit 8. The output signal of the synchronous detection circuit 9b is converted into a DC signal by the integration circuit 9c, and is further amplified by the DC amplification circuit 9d.

In the vibrating gyroscope 1 shown in FIG. 9, when the rotational angular velocity is not applied, the vibrators 2a and 2b have their tips open within the thickness of the base 7 as shown by arrows in FIG. As shown in FIG.
, Ie, the base 7 is a node portion.
Therefore, in this case, if the base 7 is supported, the vibrator 2
The vibration gyro 1 can be supported without damping the vibrations of a and 2b.

[0006]

However, in the vibrating gyroscope 1 shown in FIG. 9, when the rotational angular velocity is applied about the central axis O (FIG. 12), the vibration gyro 2 is driven by Coriolis force.
The vibrating directions of the two vibrators 2a and 2b change so as to be out of the thickness of the base 7, so that the base 7
Is twisted, and the central axis O becomes a node portion. Therefore, in the vibrating gyroscope 1, the vibrators 2a and 2b
It is necessary to support the central axis O in order not to dampen the vibrations of. In this case, the vibration gyro 1
Is supported by adhering a support member made of, for example, a thin linear metal rod as much as possible on the central axis O, but its support strength is weak. When the supporting member is formed thick to increase the supporting strength, it leads to damping of the vibrations of the vibrators 2a and 2b. When the damping of the vibration increases, the vibration becomes unstable and causes a temperature drift.

SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide a vibrating gyroscope capable of supporting a vibrator with high strength without damping the vibration.

[0008]

A vibrating gyroscope according to the present invention is arranged on both sides of two vibrators of a tuning fork type vibrating gyroscope in which one end of two vibrating vibrators is connected to a base. A vibrating gyroscope, wherein a torsion preventing arm connected to the base is provided. In the vibrating gyroscope according to the present invention, the vibrator, the base, and the arm may be integrally formed. In the vibrating gyroscope according to the present invention, the vibrator has, for example, a bimorph structure.

In the vibrating gyroscope according to the present invention, when the rotational angular velocity is not applied, the vibrator vibrates within the thickness of the base, so that the base and the arm for preventing torsion become a node portion. Further, in the vibrating gyroscope according to the present invention, when the rotational angular velocity is applied, the torsion prevention arm generates free vibration due to the reaction of Coriolis force acting on the vibrator to confine energy, so that the base is not twisted,
The base is the node part. Therefore, in the vibration gyro according to the present invention, if the base is supported, the vibration of the vibrator can be supported with high strength without damping.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments of the present invention with reference to the drawings.

[0011]

FIG. 1 is a perspective view showing an example of a vibrating gyroscope according to the present invention, and FIG. 2 is an exploded perspective view of the vibrating gyroscope. The vibrating gyroscope 10 shown in FIGS. 1 and 2 includes two vibrating pieces 12a and 12b
including.

One vibrator 12a includes, for example, a regular quadrangular prism-shaped vibrating body 14, and the vibrating body 14 includes, for example, a strip-shaped first piezoelectric substrate 16a and a second piezoelectric substrate 16a.
b. The first piezoelectric substrate 16a and the second piezoelectric substrate 16b are stacked and bonded. Further, the first piezoelectric substrate 16a and the second piezoelectric substrate 16b are polarized in opposite thickness directions. The first piezoelectric substrate 1
The direction of polarization of 6a and the second piezoelectric substrate 16b may be the same.

On the main surface of the first piezoelectric substrate 16a, two driving electrodes 18a and 18b are formed at intervals in the width direction. In addition, a detection electrode 20 is formed on the main surface of the second piezoelectric substrate 16b. Furthermore, the first
An intermediate electrode 22 is formed between the piezoelectric substrate 16a and the second piezoelectric substrate 16b.

The other vibrator 12b is connected to one vibrator 12b.
a, the first piezoelectric substrate 16a and the second piezoelectric substrate 16b to be the vibrating body 14, and the two driving electrodes 18a and 18b, the detecting electrode 20, and the intermediate electrode 22; Having.

One ends of the two vibrators 12a and 12b are connected to one end of a base 24, respectively. Base 24
Includes, for example, a first piezoelectric substrate 26a and a second piezoelectric substrate 26b having a rectangular shape. First piezoelectric substrate 26a
Are connected to one ends of the first piezoelectric substrates 16a of the two vibrators 12a and 12b, respectively. In this case, the first piezoelectric substrate 16a of the two vibrators 12a and 12b and the first piezoelectric substrate 26a of the base 24 are integrally formed of the same material. Similarly, two vibrators 12a and 12b
One ends of the second piezoelectric substrate 16b are connected to each other. In this case, the second vibrators 12a and 12b
Of the piezoelectric substrate 16b and the second piezoelectric substrate 26 of the base 24
b is integrally formed of the same material. And the first
The piezoelectric substrate 26a and the second piezoelectric substrate 26b
Laminated and bonded.

On the main surface of the first piezoelectric substrate 26a of the base 24, three driving electrodes 2 are spaced apart in the width direction.
8a, 28b and 28c are formed. In this case, 1
One driving electrode 28a is formed extending from the driving electrode 18a of one vibrator 12a, and the other driving electrode 28b is formed of the driving electrode 18b of one vibrator 12a and the other vibrator 12b. The other driving electrode 28c is formed to extend from the driving electrode 18b of the other vibrator 12b. Two detection electrodes 30a and 30b are formed on the main surface of the second piezoelectric substrate 26b of the base 24 at intervals in the width direction. In this case, one detection electrode 3
0a is formed extending from the detection electrode 20 of one vibrator 12a, and the other detection electrode 30b is formed extending from the detection electrode 20 of the other vibrator 12b. Further, an intermediate electrode 32 is formed between the first piezoelectric substrate 26a and the second piezoelectric substrate 26b of the base 24 so as to extend from the intermediate electrode 22 of the two vibrators 12a and 12b.

On both sides of the two transducers 12a and 12b, for example, two quadrangular prism-shaped arms 34a and 34b for preventing torsion extend from both ends in the width direction of the base 24 and are integrated with the base 24. Is formed. These arms 34a and 34b are connected to the vibrators 12a and 1
2b has a width twice as large as that of the vibrator 1b.
2a and 12b are formed on the same plane as the end faces.

One of the arms 34a is, for example, a strip-shaped first piezoelectric substrate 36a and a second piezoelectric substrate 36b.
including. The first piezoelectric substrate 36a extends from one end of the base 24 in the width direction of the first piezoelectric substrate 26a, and
Are formed integrally with the same material as the piezoelectric substrate 26a.
The second piezoelectric substrate 36b extends from one end of the base 24 in the width direction of the second piezoelectric substrate 26b and is integrally formed of the same material as the second piezoelectric substrate 26b. First piezoelectric substrate 36a and second piezoelectric substrate 36b
Are laminated and bonded.

The first piezoelectric substrate 3 of one arm 34a
An electrode 38 is formed on the main surface of 6a. An electrode 40 is formed on the main surface of the second piezoelectric substrate 36b of one arm 34a. Further, an intermediate electrode 42 is formed between the first piezoelectric substrate 36a and the second piezoelectric substrate 36b of one arm 34a, extending from the intermediate electrode 32 of the base 24. Note that these electrodes 38 and 40 and the intermediate electrode 42 need not be formed.

The other arm 34b is connected to one arm 34
a of the first piezoelectric substrate 2 of the base 24.
A first piezoelectric substrate 36a and a second piezoelectric substrate 36b extending from the other ends in the width direction of the second piezoelectric substrate 26a and the second piezoelectric substrate 26b and integrally formed of the same material.
And the electrodes 38 and 40 and the intermediate electrode 42.

The vibrating gyroscope 10 is formed, for example, in a state where two large piezoelectric substrates and three large electrodes are alternately laminated, grooves are formed on both electrodes, and slits are formed on the whole. , Formed by cutting the whole.

The surfaces of the two detection electrodes 30a, 30b and the two electrodes 40, 40 of the vibrating gyroscope 10 are
For example, the support member 44 may be made of a rectangular silicon sponge.
Are adhered.

As shown in FIG. 3, the vibrating gyroscope 10 has driving electrodes 1 for two vibrators 12a and 12b.
Drive electrode 28 formed extending from 8a and 18b
oscillation circuit 5 between a and 28c and drive electrode 28b
0 is connected, and the driving electrodes 28a and 28c are connected to the midpoint of the power supply voltage. Oscillation circuit 50 includes, for example, an amplification circuit and a phase correction circuit.

The two detection electrodes 30a and 30b formed from the detection electrodes 20 of the two transducers 12a and 12b are connected to two input terminals of the differential circuit 52, respectively. The differential circuit 52 includes two oscillators 1
This is for detecting a difference between output signals obtained from the detection electrodes 20 of 2a and 12b. An output terminal of the differential circuit 52 is connected to an input terminal of the synchronous detection circuit 54. Another output terminal of the oscillation circuit 50 is connected to another input terminal of the synchronous detection circuit 54. The synchronous detection circuit 54 includes a differential circuit 52
Are detected in synchronization with the output signal of the oscillation circuit 50. An output terminal of the synchronous detection circuit 54 is connected to an input terminal of the integration circuit 56. The integration circuit 56 integrates the output signal of the synchronous detection circuit 54. An output terminal of the integration circuit 56 is connected to an input terminal of the DC amplification circuit 58. The DC amplification circuit 58 is for amplifying the output signal of the integration circuit 56.

In the vibrating gyroscope 10, the oscillation circuit 50
Accordingly, the signals output from the driving electrode 18a of one vibrator 12a and the driving electrode 18b of the other vibrator 12b are amplified and the phase is corrected, and the one vibrator 12a
And the driving electrode 18a of the other vibrator 12b. As a result, an electric field is applied to the two oscillators 12a and 12b in a direction orthogonal to the polarization direction, and the two oscillators 12a and 12b
As shown by the arrows, the tips vibrate as they open and close. At this time, the two vibrators 1
Since the tip portions 2a and 12b vibrate in the same state in the polarization direction, the same output signal is obtained from the detection electrodes 20 of the two vibrators 12a and 12b. Therefore, a signal of 0 is output from the differential circuit 52.

In this state, the central axis O of the vibrating gyroscope 10 is
When a rotational angular velocity ω is applied around (FIG. 5), Coriolis force acts on the two vibrators 12a and 12b in a direction orthogonal to the vibration during non-rotation, as indicated by arrows in FIG. Due to this Coriolis force, the vibrators 12a and 12a
The vibration direction of b changes. Therefore, the two vibrators 12a
A signal corresponding to the Coriolis force is output from the detection electrodes 20 of FIGS. At this time, since the Coriolis force acts on the two vibrators 12a and 12b in opposite directions, the two vibrators 12a and 12b are displaced in opposite directions. Therefore, the two vibrators 12a and 1
The signals output from the detection electrode 20 of 2b are signals having phases opposite to each other. Therefore, if the difference between the output signals of the two detection electrodes 20 is obtained by the differential circuit 52, a large signal corresponding to the Coriolis force can be obtained.

The output signal of the differential circuit 52 is detected by a synchronous detection circuit 54 in synchronization with the signal of the oscillation circuit 50. Thereby, only the positive part or only the negative part of the output signal of the differential circuit 52 is detected. The output signal of the synchronous detection circuit 54 is converted into a DC signal by an integration circuit 56 and further amplified by a DC amplification circuit 58. The level of the output signal from the detection electrode 20 of each of the vibrators 12a and 12b is
The level of the output signal increases when a large Coriolis force acts because it is determined by the magnitude of the displacement of the tips of a and 12b. Therefore, the magnitude of the rotational angular velocity can be detected from the level of the output signal of the DC amplification circuit 58.

Also, depending on the direction in which the rotational angular velocity is applied,
The direction of the Coriolis force acting on the vibrators 12a and 12b changes. Therefore, the phases of the signals output from the two detection electrodes 20 also change, and signals having opposite phases are output from the differential circuit 52 depending on the direction of the rotational angular velocity. Therefore, in the synchronous detection circuit 54, if the positive part of the signal is detected when the rotational angular velocity is applied in one direction, the negative part of the signal is detected when the rotational angular velocity is applied in the other direction. Therefore, the polarity of the output signal of the DC amplification circuit 58 changes depending on the direction in which the rotational angular velocity is applied. That is, the direction to which the rotational angular velocity is applied can be known from the polarity of the output signal of the DC amplifier circuit 58.

In the vibrating gyroscope 10, when the rotational angular velocity is not applied, the vibrators 12a and 12b vibrate such that their tips open and close as indicated by arrows in FIG. Therefore, in this case, the portions indicated by oblique lines in FIG.
The two arms 34a and 34b form a node portion.
Therefore, in this case, the base 24 and the two arms 34a
And support member 44 adhered to the lower surface of
By supporting (FIG. 1), the vibration gyro 10 can be supported with high strength without damping the vibrations of the vibrators 12a and 12b.

In the vibrating gyroscope 10, when a rotational angular velocity is applied about the central axis O (FIG. 5), Coriolis force is applied to the vibrators 12a and 12b as shown by arrows in FIG. Join. In this case, the two arms 34a and 34b become weights, and the vibrator 12
Due to the reaction of the Coriolis force acting on a and 12b, as shown by the arrow in FIG. 5, free vibration is caused to confine energy. Therefore, in this case, a portion indicated by oblique lines in FIG. 5, that is, a portion connected to the base 24 in the base 24 and the two arm portions 34a and 34b is a node portion. Therefore, also in this case, by supporting the support member 44 adhered to the lower surface of the base 24 or the like,
The vibration gyro 10 can be supported with high strength without damping the vibrations of the vibrators 12a and 12b.

FIG. 6 is a perspective view showing another example of the vibrating gyroscope according to the present invention. Vibrating gyroscope 10 shown in FIG.
In this case, the width of the arms 34a and 34b is formed to be as narrow as the width of the vibrators 12a and 12b, as compared with the vibrating gyroscope 10 shown in FIGS.

FIG. 7 is a perspective view showing still another example of the vibrating gyroscope according to the present invention. In the vibrating gyroscope 10 shown in FIG. 7, the width of the arms 34a and 34b is formed to be smaller than half the width of the vibrators 12a and 12b, as compared with the vibrating gyroscope 10 shown in FIGS.

Each vibrating gyroscope 10 shown in FIGS. 6 and 7
However, it operates in the same manner as the vibrating gyroscope 10 shown in FIGS.

In the vibrating gyroscope 10 shown in FIGS. 1 and 2, the arms 34a and 34b are wider than the vibrating gyroscopes 10 shown in FIGS. Arm 34
Since the masses of a and 34b are heavy, the amplitude of the vibration in the vertical direction of the arms 34a and 34b is stabilized and reduced, and a space such as a case for accommodating the vibration gyro can be formed thin.

On the other hand, in the vibration gyro 10 shown in FIG.
Since the masses of the arms 34a and 34b are smaller than those of the vibrating gyroscopes 10 shown in FIGS. 1, 2 and 6, the amplitude of the vibration in the vertical direction of the arms 34a and 34b is large, but the width of the arms 34a and 34b is small. Because it ’s narrow,
The practical installation surface of the vibrating gyroscope is reduced.

In the vibration gyro 10 shown in FIG.
The vibration gyro is located between the vibration gyro 10 shown in FIGS. 1 and 2 and the vibration gyro 10 shown in FIG. 7 in terms of the size of the installation surface of the vibration gyro and the thickness of the space for accommodating the vibration gyro.

FIG. 8 is a front view showing another example of the supporting structure of the vibrating gyroscope. In the support structure of the vibrating gyroscope 10 shown in FIG. 8, the base 24 and the lower surfaces of the arms 34a and 34b are bonded to another member 48 with a silicone adhesive 46.
As described above, the lower surface of the base 24 or the like of the vibrating gyroscope 10 may be bonded to another member with the adhesive.

In the above-described vibrating gyroscope 10, the two vibrators 12a and 12b are each formed in a so-called bimorph structure, but in the present invention, the vibrators may be formed in another structure such as a unimorph structure. . Also, for the base 24 and the arms 34a and 34b,
Similarly, it may be formed in another structure such as a unimorph structure.

[0039]

According to the present invention, it is possible to obtain a gyro capable of supporting the vibrator with high strength without damping the vibration.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a vibrating gyroscope according to the present invention.

FIG. 2 is an exploded perspective view of the vibrating gyroscope shown in FIG.

FIG. 3 is an illustrative view showing a circuit for using the vibrating gyroscope shown in FIGS. 1 and 2;

FIG. 4 is an illustrative view showing a node portion in the case where no rotational angular velocity is applied to the vibration gyro shown in FIGS. 1 and 2;

FIG. 5 is an illustrative view showing a node portion when a rotational angular velocity is applied in the vibrating gyroscope shown in FIGS. 1 and 2;

FIG. 6 is a perspective view showing another example of the vibrating gyroscope according to the present invention.

FIG. 7 is a perspective view showing still another example of the vibrating gyroscope according to the present invention.

FIG. 8 is a front view showing another example of the support structure of the vibrating gyroscope.

FIG. 9 is a perspective view showing an example of a conventional vibrating gyroscope.

FIG. 10 is an illustrative view showing a circuit for using the vibrating gyroscope shown in FIG. 9;

11 is an illustrative view showing a node portion in the case where no rotational angular velocity is applied to the vibration gyro shown in FIG. 9;

FIG. 12 is an illustrative view showing a node portion in the case where a rotational angular velocity is applied to the vibration gyro shown in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vibration gyroscope 12a, 12b Vibrator 14 Vibrator 16a First piezoelectric substrate 16b Second piezoelectric substrate 18a, 18b Driving electrode 20 Detection electrode 22 Intermediate electrode 24 Base 26a First piezoelectric substrate 16b First 2 piezoelectric substrates 28a, 28b, 28c Driving electrodes 30a, 30b Detection electrodes 32 Intermediate electrodes 34a, 34b Arms 36a First piezoelectric substrate 36b Second piezoelectric substrates 38, 40 Electrodes 42 Intermediate electrodes 44 Supporting members 46 Silicon adhesive 48 Other members 50 Oscillation circuit 52 Differential circuit 54 Synchronous detection circuit 56 Smoothing circuit 58 DC amplifier circuit

Claims (3)

[Claims] 1. A tuning fork-type vibrating gyroscope in which one ends of two vibrating vibrators of a resonating type are connected to a base, respectively, and are disposed on both sides of the two vibrators and are prevented from torsion connected to the base. Characterized by the provision of an arm for
Vibrating gyro. 2. The vibrating gyroscope according to claim 1, wherein the vibrator, the base, and the arm are integrally formed. 3. The vibrating gyroscope according to claim 1, wherein the vibrator has a bimorph structure.