JPH0762617B2 - Vibrating gyro - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration gyro,
In particular, the present invention relates to a vibration gyro used in a navigation system mounted on an automobile or the like.

[0002]

2. Description of the Related Art FIG. 8 is a perspective view showing an example of a conventional vibrating gyro, which is the background of the present invention, and FIG. 9 is a sectional view taken along line IX-IX of the vibrating gyro shown in FIG. The vibrating gyro 1 includes a vibrating body 2. The vibrating body 2 is formed in a columnar shape having a square cross section. The vibrating body 2 is formed of a constant elastic metal material or the like.

Piezoelectric detection elements 3 and 3 are formed on a pair of opposing side surfaces of the vibrating body 2. This piezoelectric detector
The children 3 and 3 are piezoelectric ceramics 3a, as shown in FIG. 9, for example .
The electrodes 3b are formed on both surfaces of.

Further, the piezoelectric drive element 4 is provided on each of the pair of side surfaces of the vibrating body 2 on which the piezoelectric detection element 3 is not formed.
Is formed. This piezoelectric drive element 4 is also, for example, a piezoelectric detector.
Similar to the output element 3, the piezoelectric ceramics 4a are formed with electrodes 4b on both surfaces.

The vibrating gyro 1 includes a vibrating body 2
Is supported by the support member 5 at the node points of. Therefore, when a drive signal is applied to the piezoelectric drive element 4, the vibrating body 2 will move to the piezoelectric drive element 4 as shown exaggeratedly in FIG.
Bending vibration occurs in the direction orthogonal to the main surface of the.

In this state, when the vibrating gyro 1 rotates about its axis, Coriolis force acts in a direction orthogonal to the vibrating direction. Therefore, as exaggeratedly shown in FIG. 11, the vibration direction of the vibrating body 2 is changed by the Coriolis force, and an output voltage is generated in the piezoelectric detection element 3. Since this output voltage is proportional to the amount of bending in the direction orthogonal to the main surface of the piezoelectric detection element 3, the rotational angular velocity of the vibration gyro 1 can be known by measuring this output voltage. The same applies when the vibrating gyro 1 rotates about an arbitrary axis along the axis.

[0007]

In such a conventional vibrating gyro, when the vibrating gyro is rotated, the direction in which the vibrating body bends, that is, the direction in which the piezoelectric detecting element bends (the bending vibration direction vector when no rotation occurs and the Coriolis direction). Since the direction of the combined vector with the displacement vector due to the force is deviated from the direction orthogonal to the main surface, the output voltage generated in the piezoelectric detection element was small. Therefore, it is difficult to measure the rotational angular velocity applied to the vibration gyro from this output voltage. Therefore, in order to increase the S / N ratio, it is necessary to adjust the output voltage to 0 when the motor is not rotating. However, for example, by cutting the corners of the vibrating body, the output voltage is adjusted.
The adjustment was difficult.

Therefore, a main object of the present invention is to provide a vibrating gyro which can increase the output voltage during rotation, and therefore does not necessarily require zero output voltage during non-rotation.

[0009]

The present invention is based on a drive source.
A columnar vibrating body for bending vibrate I, is located on the side not parallel to each other of the vibrating body, and at least two piezoelectric detector elements for detecting the direction of the bending vibration of the vibrating body, the piezoelectric detection element , they are arranged symmetrically on either side of the plane including both the vibration direction at the time of no rotation of the vibrator and the center axis of the vibration member, and stiffness caused during rotation of the vibrator
A vibrating gyroscope arranged so as to be neither parallel nor orthogonal to the direction of the orienting force, the piezoelectric gyro being at least two piezoelectric detectors.
A vibrating gyro, wherein a difference between outputs from the elements is used as a detection voltage.

[0010]

[Operation] When bending vibration is applied to the vibrating body,Piezoelectric detector
Is both sides of the plane including the vibration direction of the vibrating body when it is not rotating.
Since they are arranged symmetrically with respect to each other, the difference in output voltage is almost
It becomes zero.

When the vibrating gyro rotates about its axis, the vibrating direction changes due to the Coriolis force, but the vibrating body rotates at a position substantially orthogonal to the vibrating direction , that is, the rotating direction.
Not parallel to and orthogonal to the direction of the Coriolis force that sometimes occurs
Piezoelectric sensing element have positions are present, the piezoelectric detector element
The output voltage generated in the child is large. On the other hand, the output voltage of the piezoelectric sensing element formed on the other side becomes small, these pressure
A large output signal can be obtained by taking the difference between the output voltages of the charge detection elements .

[0012]

According to the present invention, when the vibrating gyro is not rotating, the difference between the output voltages of the piezoelectric detecting elements is almost zero.
Therefore, it can be detected that the rotational angular velocity is not applied. In addition, the bending direction of the vibrating body when the vibrating gyro rotates and the side surface on which the piezoelectric detecting element is provided are substantially orthogonal to each other, that is, the Coriolis generated during rotation.
Since it is neither parallel nor orthogonal to the direction of force ,
The output voltage generated in the piezoelectric detection element is larger than that in the conventional vibration gyro. Furthermore, since the difference in the output voltage of the piezoelectric detection element is large, a large output signal can be obtained even if a small rotational angular velocity is applied. Therefore, it is easy to detect the rotational angular velocity with this vibrating gyro.
Therefore, the delicate work of cutting the corners of the vibrating body in order to increase the S / N ratio becomes unnecessary.

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

[0014]

1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II of the embodiment shown in FIG. The vibrating gyro 10 includes a vibrating body 12. The vibrating body 12 is formed, for example, in a regular triangular prism shape.
The vibrating body 12 is formed of a material that generally causes mechanical vibration, such as elinvar, iron-nickel alloy, quartz, glass, crystal, and ceramic. In order to make this embodiment more practical, piezoelectric detecting elements 14 and 16 are formed in the central portions of the two side surfaces of the vibrating body 12, respectively.
This piezoelectric detecting element 14 is, for example, as shown in FIG.
Electrodes 14b and 14c are formed on both sides of the piezoelectric ceramic 14a. Then, the one electrode 14c is bonded to the side surface of the vibrating body 12. Similarly, the piezoelectric detection element 16
Also, for example , electrodes 16b and 16c are formed on both surfaces of the piezoelectric ceramic 16a, and one electrode 16c is bonded to the vibrating body 12.

Piezoelectric detection elements 14 and 16 of the vibrator 12.
Two piezoelectric drive elements 18 and 20 are formed at the central portion in the longitudinal direction on the side surface where no is formed. these
The piezoelectric drive elements 18 and 20 are formed side by side in the width direction of the side surface of the vibrating body 12. The piezoelectric driving element 18, if
For example, as shown in FIG. 2, the electrodes 18 are formed on both sides of the piezoelectric ceramic 18a.
b and 18c are formed. Then, one electrode 18c is bonded to the vibrating body 12. Similarly, pressure
Also in the electric drive element 20, electrodes 20b and 20c are formed on both surfaces of the piezoelectric ceramic 20a, for example , and one electrode 20c is bonded to the vibrating body 12. In this example,
The piezoelectric ceramics 18a and 20a and the electrodes 18c and 20c bonded to the vibrating body 12 are formed in common.

By applying a drive signal between the piezoelectric drive elements 18 and 20, the vibrating body 12 undergoes bending vibration, but the support members 22 and 24 are formed at the node points thereof. The support members 22 and 24 are formed, for example, by welding a metal wire or the like to the vibrating body 12.

This vibrating gyro 10 is used in a circuit configuration as shown in FIG. That is, the vibration gyro 10
An oscillation circuit 30 is connected to one of the piezoelectric drive elements 18, and the oscillation circuit 30 is connected to the other piezoelectric drive element 20 via a phase circuit 32 and an AGC circuit 34.
Therefore, the signal amplified by the oscillation circuit 30 is phase-controlled by the phase circuit 32, gain-controlled by the AGC circuit 34, and applied to the piezoelectric drive element 20. Then, the oscillator circuit 30, the phase circuit 32 and the AGC circuit 34 are provided.
This provides a stable drive signal at the resonance frequency of the vibrating body 12.

Further, the piezoelectric detecting elements 14 and 16 are
It is connected to the differential amplifier 36. The differential amplifier 36 measures the difference between the output voltages generated in the piezoelectric detecting elements 14 and 16. The differential amplifier 36 is a synchronous detection circuit 38.
Connected to. The synchronous detection circuit 38 is connected to the oscillation circuit 30, and the output of the differential amplifier 36 is detected in synchronization with the oscillation frequency of the oscillation circuit 30. The signal detected by the synchronous detection circuit 38 is smoothed by the smoothing circuit 40, and further the DC amplifier 4
It is amplified by 2 and becomes an output signal.

When the vibrating gyro 10 does not rotate, as shown exaggeratedly in FIG. 4, the vibrating gyro 10 vibrates flexibly in a direction orthogonal to the principal surfaces of the piezoelectric drive elements 18 and 20. In this case, the piezoelectric detection elements 14 and 16 are
12 including the central axis of 12 and the vibration direction of the vibrating body 12
It is arranged symmetrically on both sides. Therefore, since the amounts of bending of the surfaces of the vibrating body 12 on which the piezoelectric detection elements 14 and 16 are formed are the same, the output voltages generated at these piezoelectric detection elements 14 and 16 are equal. Therefore, the output voltages of the piezoelectric detection elements 14 and 16 are canceled by the differential amplifier 36, and the output of the differential amplifier 36 becomes zero. That is, the piezoelectric detection element 14 is L and the piezoelectric detection element 16 is
Is R, and the output voltage of each without rotation is A,
The output of the differential amplifier 36 is LR = A-A = 0.
Therefore, in the vibrating gyro 10, the output when not rotating can be easily set to zero.

Further, when the vibrating gyro 10 is rotated about its axis, Coriolis force acts in a direction orthogonal to the vibrating direction of the vibrating body 12. In this case, as shown exaggeratedly in FIG. 5, the vibrating direction of the vibrating body 12 is deviated from the vibrating direction when there is no rotation. At this time, for example, the piezoelectric detection element 1
6 is a piezoelectric sensor in a direction close to the direction orthogonal to the main surface.
The child 14 makes a bending motion in a direction close to the direction parallel to the main surface thereof. Therefore, the output voltage generated in the piezoelectric detection element 16 increases and the output voltage generated in the piezoelectric detection element 14 decreases. That is, when the output voltage corresponding to the Coriolis force during rotation is α, and is expressed by the above-described equation, LR = (A−α) − (A + α) = − 2α.
Therefore, a larger output can be obtained from the differential amplifier 36 as compared with the conventional vibration gyro. Therefore, the use of the vibration gyro 10 makes it easier to detect the rotational angular velocity than the case of using the conventional vibration gyro.

Further, in the above embodiment, the vibrating body 12 is formed in a regular triangular prism shape, but the vibrating body 12 may be formed in an isosceles triangular prism shape. In this case, the piezoelectric detection elements 14 and 16 may be formed on the side surfaces of the vibrating body 12 having the same area.

Further, the vibrating body 12 may be formed in a triangular prism other than the isosceles triangular prism, or may be formed in a polygonal prism such as a pentagonal prism or a hexagonal prism. In this case, the piezoelectric detection element may be formed on a plurality of side surfaces of the vibrating body on which the piezoelectric drive element is not formed and which are not parallel to each other.

In the embodiment shown in FIG. 1, the supporting member 2
Each of 2 and 24 is connected to the vibrating body 12 at one point, but may be connected to each of two points as shown in FIG. That is, these support members 22 and 24 are
It may be connected to the node point of the vibrating body 12.

Further, the piezoelectric drive elements 18 and 20 are
As shown in FIG. 7, it may be formed at intervals in the longitudinal direction of the vibrating body 12.

[Brief description of drawings]

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

2 is a cross-sectional view taken along the line II-II of the embodiment shown in FIG.

FIG. 3 is a block diagram showing a circuit for using the vibrating gyro shown in FIGS. 1 and 2.

FIG. 4 is an illustrative view showing a vibrating state when the vibrating gyro shown in FIGS. 1 and 2 is not rotating.

5 is an illustrative view showing a vibrating state when the vibrating gyro shown in FIGS. 1 and 2 is rotating. FIG.

FIG. 6 is a perspective view showing a modified example of the present invention.

FIG. 7 is a perspective view showing still another modified example of the present invention.

FIG. 8 is a perspective view showing an example of a conventional vibrating gyro, which is the background of the present invention.

9 is a line IX-IX of the conventional vibrating gyro shown in FIG.
FIG.

10 is an illustrative view showing a vibrating state when the conventional vibrating gyro shown in FIGS. 8 and 9 is not rotating. FIG.

FIG. 11 is an illustrative view showing a vibrating state when the conventional vibrating gyro shown in FIGS. 8 and 9 is rotating.

[Explanation of symbols]

10 Vibration Gyro 12 Vibrating Body 14 Piezoelectric Detection Element 16 Piezoelectric Detection Element 18 Piezoelectric Drive Element 20 Piezoelectric Drive Element

Claims (1)

[Claims] 1. A column-shaped vibrating body for causing flexural vibration by a drive source , and at least two piezoelectric detecting elements arranged on non-parallel side surfaces of the vibrating body for detecting the direction of flexural vibration of the vibrating body. wherein the said piezoelectric detector elements, the are arranged symmetrically on either side of the plane including both the vibration direction at the time of no rotation of the central shaft and the vibrating body of the vibration member, and green during rotation of the vibrating member
Make sure it is neither parallel nor orthogonal to the direction of the Coriolis force.
A arranged vibrating gyroscope in, characterized by a detection voltage difference between the output from said at least two piezoelectric detector elements, a vibration gyro.