JPH05288554A - Vibrating gyroscope - Google Patents

Abstract

PURPOSE:To provide a vibrating gyroscope capable of accurately measuring the rotational angular velocity without reducing sensitivity when the ambient temperature is changed. CONSTITUTION:A vibrating gyroscope 10 contains a vibrator 12. The vibrator 12 is formed into a triangle pole shape with a constant-elasticity metal material. Piezoelectric elements 14, 16, 18 are formed at the center sections of side faces of the vibrator 12. The piezoelectric elements 14, 16, 18 are divided at the center section in the longitudinal direction of the vibrator 12 respectively. The divided piezoelectric elements 14, 16, 18 are connected with lead wires 20 made of a soft material such as gold.

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, for example, the present invention relates to a vibration gyro that can be applied to a navigation system that detects the position of a moving body by detecting an angular velocity and performs appropriate guidance, or a yaw rate sensor that detects external vibration and appropriately suppresses vibration.

[0002]

2. Description of the Related Art FIG. 4 (A) is a perspective view showing a conventional vibrating gyro which is the background of the present invention, and FIG. 4 (B) is a sectional view thereof. The vibrating gyro 1 includes a vibrating body 2.
The vibrating body 2 is made of, for example, a constant elastic metal material and is formed into a regular triangular prism shape. Piezoelectric elements 3, 4, and 5 are formed in the central portions of the side surfaces of the vibrating body 2, respectively. Piezoelectric elements 3, 4, 5
Is, for example, one in which electrodes are formed on both surfaces of a piezoelectric ceramic. Then, the piezoelectric elements 3, 4, 5 are adhered to the side surface of the vibrating body 2 with an adhesive or the like. The two piezoelectric elements 3 and 4 are used for driving and detecting an output signal. The other piezoelectric element 5 is used for feedback.

In this vibration gyro 1, an oscillation circuit or the like is connected between the driving piezoelectric elements 3 and 4 and the feedback piezoelectric element 5 as a feedback loop for self-excited driving.
The oscillator 2 flexurally vibrates in the direction orthogonal to the surface on which the feedback piezoelectric element 5 is formed by the signal from the oscillation circuit. When the vibration gyro 1 rotates in this state, an output difference occurs between the two piezoelectric elements 3 and 4 for detecting the output signal, and the rotational angular velocity can be detected by measuring the output difference.

[0004]

In such a vibration gyro, the linear expansion coefficient of the vibrating body, the piezoelectric element, and the adhesive for bonding the piezoelectric element are different from each other. Therefore, stress acts on the vibrating body due to the temperature change around the vibrating gyro. In particular, when the vibrating body bends and vibrates, as shown in FIG. 5, the displacement of the central portion of the vibrating body in the longitudinal direction becomes maximum. Therefore, the influence of stress becomes large when the vibrator is placed at the center in the length direction. This stress affects the flexural vibration of the vibrating body, which may cause an error in the measured rotational angular velocity.

Therefore, a main object of the present invention is to provide a vibrating gyroscope capable of accurately measuring the rotational angular velocity without lowering the sensitivity even when the ambient temperature changes.

[0006]

According to the present invention, a vibrating body having a polygonal prism shape and a piezoelectric element formed on a side surface of the vibrating body are provided, and the piezoelectric element is divided at a central portion in a length direction of the vibrating body. It is a vibrating gyro.

[0007]

Since the piezoelectric element is divided, the stress applied to the vibrating body is dispersed as compared with the integrally formed piezoelectric element. Further, since the piezoelectric element is divided at the portion where the displacement of the central portion of the vibrating body in the length direction is maximum, stress is not applied to the portion where the displacement of the vibrating body is maximum.

[0008]

According to the present invention, since the stress applied to the vibrating body is dispersed by the change in the ambient temperature, the flexural vibration of the vibrating body is less affected. In addition, since no stress is applied to the portion where the flexural vibration of the vibrating body has the maximum displacement, the piezoelectric element has little influence on the flexural vibration of the vibrating body. Therefore, the rotational angular velocity applied to the vibration gyro can be accurately measured. Further, since the divided piezoelectric elements are connected by the lead wires, the sensitivity can be kept good.

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

[0010]

1A is a perspective view showing an embodiment of the present invention, and FIG. 1B is a sectional view taken along line IB-IB in FIG. 1A. The vibrating gyro 10 includes a vibrating body 12. The vibrating body 12 is, for example, a constant elastic metal material,
It is formed in a regular triangular prism shape. Piezoelectric elements 14, 16 and 18 are formed on the side surfaces of the vibrating body 12, respectively. The piezoelectric element 14 includes, for example, a piezoelectric body 14a.
Electrodes 14b and 14c are formed on both surfaces of a. And
One of the electrodes 14c is attached to the vibrating body 12 by an adhesive or the like.
Glued to the sides of. Similarly, the piezoelectric elements 16 and 18 are
The piezoelectric bodies 16a and 18a are included, and electrodes 16b and 16c and electrodes 18b and 18c are formed on both surfaces of the piezoelectric bodies 16a and 18a. Then, one of the electrodes 16c and 18c is bonded to the side surface of the vibrating body 12.

As shown in FIG. 2, each of the piezoelectric elements 14, 16 and 18 is divided into two at the center of the vibrating body 12 in the longitudinal direction. Then, the divided piezoelectric elements 14 are connected by the lead wires 20 formed of a soft metal such as gold. Similarly, the divided piezoelectric element 16 is connected by the lead wire 20, and the divided piezoelectric element 18 is also connected by the lead wire 20. The lead wire 20 is drawn to the outside and connected to an oscillation circuit, an output signal detection circuit, and the like. In this vibrating gyro 10, two piezoelectric elements 1
4, 16 are used for driving and detecting an output signal, and another piezoelectric element 18 is used for feedback. A damping material or the like may be applied to the lead wires 20 between the divided piezoelectric elements in order to suppress the vibration of the lead wires 20.

In this vibrating gyro 10, the piezoelectric elements 14 and 16 used for driving and the piezoelectric element 18 for feedback are used.
An oscillation circuit or the like is connected as a feedback loop for self-excited driving. Therefore, the vibrating body 12 flexurally vibrates in the direction orthogonal to the surface on which the feedback piezoelectric element 18 is formed, in response to the signal from the oscillation circuit.

In this state, when the vibrating gyroscope 10 rotates about its axial direction, the Coriolis force changes the vibrating direction of the vibrating body 12, resulting in a difference in voltage generated between the piezoelectric elements 14 and 16 used for detecting the output signal. Occurs.
Therefore, a large output can be obtained by detecting the difference between the output voltages of the piezoelectric elements 14 and 16. By measuring this output, the rotational angular velocity applied to the vibration gyro 10 can be detected.

In this vibrating gyroscope 10, the piezoelectric elements 14, 16 and 18 are provided at the center of the vibrating body 12 in the longitudinal direction.
Since the vibrating body 12 is divided, even if the ambient temperature changes, the vibrating body 12 and the piezoelectric elements 14, 16 and 18 and the viscous body 12 due to the difference in the coefficient of linear expansion of the adhesive for bonding them
The stress acting on is dispersed. Further, as shown in FIG. 3, when the vibrating body 12 is flexurally vibrating, the displacement of the central portion in the longitudinal direction of the vibrating body 12 is maximum, but there is no piezoelectric element in this portion. Therefore, the piezoelectric element has little influence on the flexural vibration of the vibrating body 12. From these facts, the vibration gyro 10 can accurately measure the rotational angular velocity even if the ambient temperature changes. Moreover, since the divided piezoelectric elements are connected by the lead wires, the sensitivity can be kept good.

Although the vibrating body 12 is formed in the shape of a regular triangular prism in the above-mentioned embodiment, the vibrating body 12 may have another polygonal column shape.

[Brief description of drawings]

FIG. 1A is a perspective view showing an embodiment of the present invention, and FIG. 1B is a sectional view taken along line IB-IB in FIG.

FIG. 2 is a side view of the vibrating gyro shown in FIG.

FIG. 3 is a side view showing a state where the vibrating gyro shown in FIG. 1 is flexibly vibrating.

FIG. 4A is a perspective view showing an example of a conventional vibrating gyro, which is the background of the present invention, and FIG. 4B is a sectional view thereof.

FIG. 5 is a side view showing a state in which the conventional vibrating gyro shown in FIG. 4 is flexibly vibrating.

[Explanation of symbols]

 10 vibrating gyro 12 vibrating body 14, 16, 18 piezoelectric element

Claims (1)

[Claims] 1. A vibrating gyroscope comprising a vibrating body having a polygonal prism shape and a piezoelectric element formed on a side surface of the vibrating body, wherein the piezoelectric element is divided at a central portion in a longitudinal direction of the vibrating body.