JPH04134208A - Angular velocity sensor - Google Patents

Abstract

PURPOSE:To provide an angular velocity sensor with good machining quality by fitting a detecting piezoelectric element disposed on the cut part in the side surface of a column material whose section is circular and a driving piezoelectric element disposed on the cut part where the element is not disposed. CONSTITUTION:When a driving signal is inputted in a driving piezoelectric element 14 with angular velocity not working upon an angular velocity sensor 10, the sensor 10 makes bending movement in an orthogonal direction to the main surface of the element 14. At this time, a signal outputted from detecting piezoelectric elements 12, 13 is compensated in a detecting circuit 32, and it meets a condition where angular velocity does not work. When the sensor 10 rotates around the axis, however, Coriolis force works in an orthogonal direction to the vibrating direction of a vibrator 11. The vibrating direction of the vibrator 11 is shifted from the vibrating direction at the time of no rotation. The element 12 makes bending moment in an orthogonal direction to the main surface, and the element 13 makes bending moment in a direction next to the parallel direction to the main surface. For this reason, outputted voltage generated in the element 12 becomes higher, and outputted voltage generated in the element 13 become lower. It is thus possible to detect angular velocity easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an angular velocity sensor, and is particularly used for mounting on an automobile and detecting its movement state.

(Prior art) As a prior art related to the present invention, Japanese Patent Application Laid-Open No. 2-51066
There are some listed in the issue. The vibrating gyroscope disclosed in this prior art is shown in FIG.

The vibrating gyroscope 50 includes a vibrating body 51.

The vibrating body 51 is formed, for example, in the shape of an equilateral triangle.

This vibrating body 51 is made of a constant elastic metal material.

Detection piezoelectric elements 52 and 53 are arranged at the center of two side surfaces of the vibrating body 51, respectively. Two driving piezoelectric elements 53 and 54 are formed at the center in the longitudinal direction on the side surface of the vibrating body 51 where the detection piezoelectric elements 52 and 53 are not provided. These driving piezoelectric elements 53
and 54 are formed side by side in the width direction of the vibrating body 51.

(Problem to be Solved by the Invention) In the vibrating gyroscope according to the prior art, the vibrating body is a triangular prism, and the direction in which the vibrating body is bent (the direction in which the detecting piezoelectric element is bent) and the detecting piezoelectric element are perpendicular to each other. By arranging the detection piezoelectric element, the output voltage generated in the detection piezoelectric element could be increased. However, since the vibrating body is a triangular prism, it is necessary to ensure sufficient machining accuracy when forming the vibrating body.

The present invention has been made to improve the workability of the conventional technology, and an object thereof is to provide a vibrating body for an angular acceleration sensor with good workability.

σStructure of the Invention] (Means for Solving the Problems) The technical means taken to solve the above technical problems is as follows: A vibrating body having a plurality of notches formed therein; a piezoelectric detection element disposed on at least one notch of the vibrating body; and a piezoelectric detection element disposed on a notch on which the piezoelectric detection element is not disposed. The angular velocity sensor has a driving piezoelectric element that drives the vibrating body.

(Function) By using the above technical means, the detection piezoelectric element is located perpendicular to the vibration direction, so the detection piezoelectric element can detect all the angular velocity components, and the vibrating body It has become possible to reliably detect minute angular velocity or action as an electrical signal.

(Embodiments) Hereinafter, preferred embodiments using the technical means of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of the angular velocity sensor 10. FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1.

This angular velocity sensor 10 includes a vibrating body 11. In this embodiment, the vibrating body 11 is a cylindrical member, and has notches 11a and llb on its outer periphery.

Ilc is formed. The vibrating body 11 is made of, for example, Ni
, Fe, Cr and Ti. Detection piezoelectric elements 12 and 13 are disposed at the center of the two notches 11b and llc of the vibrating body 11.

As shown in FIG. 2, electrodes 12a and 12b are fixed to both surfaces of the detection piezoelectric element 12. Similarly, electrodes 13a and 13b are fixed to both sides of the detection piezoelectric element 13.

The remaining notch portion 1ia of the vibrating body 11 is provided with a drive piezoelectric element 14. As shown in FIG. 2, electrodes 14a are provided on both sides of the driving piezoelectric element 14.

14b is provided. Two electrodes 12a, 13. are in direct contact with each notch. a and 14a are directly bonded to the vibrating body.

By applying a drive signal to this drive piezoelectric element 14, bending vibration is excited in the vibrating body 11.

This angle sensor 10 is used under the circuit configuration shown in FIG. An AGC circuit 30 is connected to the driving piezoelectric element 14 of the angular velocity sensor 10. AGC circuit 30
is for controlling the gain of the drive signal. AG
An oscillation circuit 31 is connected to the C circuit 30. The oscillation circuit 31 outputs a pulse signal having a predetermined period. An output signal output from one detection piezoelectric element 12 is connected to an oscillation circuit 31. This detection piezoelectric element 1
The signal output from 2 becomes a feedback signal,
The period, etc. of the pulse signal output from the oscillation circuit 31 is stabilized. Output lines from the detection piezoelectric elements 12 , 13 are connected to the detection circuit 32 . The electrical signal input to the detection circuit 32 is subjected to electrical processing (such as determining the difference between two detection piezoelectric elements or smoothing the electrical signal). The electrical signal processed within the detection circuit 32 is amplified by the amplifier circuit 33 and output as an output signal.

When a drive signal is input to the driving piezoelectric element 14 in a state where no angular velocity acts on the angular velocity sensor 10, the angular velocity sensor 10 moves as shown in FIG. That is, the angular velocity sensor 10 makes a bending motion in a direction perpendicular to the main surface of the driving piezoelectric element 14. At this time, since the amount of bending of the surface of the vibrating body 11 on which the detection piezoelectric elements 12 and 13 are arranged is the same,
The output voltages generated in the detection piezoelectric elements 12 and 13 become equal. In other words, the signals output from the detection piezoelectric elements 12 and 13 are canceled out within the detection circuit 32, which corresponds to a state in which no angular velocity is acting.

When the angular velocity sensor 10 rotates about its axis, a force J acts in a direction perpendicular to the vibration direction of the vibrating body 11. At this time, a force J acts as shown in FIG. Such a movement occurs in the angular velocity sensor lO.

The direction of vibration of the vibrating body IL will deviate from the direction of vibration during non-rotation. The detection piezoelectric element 12 makes a bending motion in a direction close to the direction perpendicular to its two principal surfaces, and the detection piezoelectric element 13 makes a bending motion in a direction close to the direction parallel to its principal surface. Therefore, the output voltage generated by the detection piezoelectric element 12 becomes larger, and the output voltage generated by the detection piezoelectric element 13 becomes smaller. Therefore, the detection of angular velocity becomes easy.

In this embodiment, the angular velocity was detected using the output voltages generated in the two detection piezoelectric elements 1213, but the output voltage of either one of the detection piezoelectric elements 1213 may be measured.

FIG. 7 shows an example of a method of supporting the angular velocity sensor 10. Support wires 41 are attached to the fixed parts 40a...40b.
a, 41b, 42a, 42b are connected. The support lines 41a, 41b, 42a, and 42b intersect with each other at four locations, and are fixed to each other at these intersections. The angular velocity sensor 10 is fixed to five support lines 41a and 141b.

:Effects of the invention: The present invention provides a unique vibrating body.Thus, the vibrating body can be made into a vibrating body with two excellent workability, and the adhesive surface of the detection piezoelectric element can be easily broken. I hope you can get great results when

[Brief explanation of the drawing]

Figure 1 is a perspective view of the angular velocity sensor, Figure 2 is the ■- of Figure 1.
■A cross-sectional view along the line, Figure 3 is a block diagram of the electric circuit used when using the angular velocity sensor, Figure 4 is an explanatory diagram showing the vibration state when the angular velocity sensor is not rotating, Figure 5 is the angular velocity An explanatory diagram showing the vibration state when the sensor is rotating, FIG. 6 is an explanatory diagram showing the fixed state of the angular velocity sensor,
FIG. 7 is a perspective view of a vibrating gyroscope according to the prior art that is the background of the present invention. 11b, llc... Notch, vibrating body, 13... Piezoelectric element for detection, piezoelectric element for drive.

Claims (1)

[Claims] A vibrating body having a plurality of notches formed at predetermined intervals on the side surface of a columnar member having a circular cross section; a detection device disposed on at least one notch of the vibrating body. Piezoelectric element: and an angular velocity sensor having a driving piezoelectric element for driving the vibrating body, which is disposed on a notch where the detection piezoelectric element is not disposed.