JPH11281369A - Tuning fork type vibration gyro - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To provide a small-sized vibrating gyroscope with a simple manufacturing process, high reliability and high reliability. The two arms are made of a piezoelectric material.
In the tuning fork-shaped vibrating gyroscope having the arm 20, the arm driving electrodes 111, 113, 12
A detection electrode 141 for detecting an angular velocity due to a change in capacitance at a position close to and adjacent to a tuning fork vibration surface which is the same plane as a plane including the two arms;
143 were provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tuning fork type vibrating gyroscope for detecting a rotational angular velocity.

[0002]

2. Description of the Related Art FIG. 6 is a schematic structural view of a conventional vibrating gyroscope disclosed in Japanese Patent Application Laid-Open No. 58-174854.

The vibrating gyroscope has tuning fork arms 60 and 61.
Have vibrating sound pieces 62 and 63 configured to vibrate at right angles to the vibration direction of the tuning fork arm. The tuning fork arms 60 and 61 and the vibrating reeds 62 and 63 are made of metal, and are thinned in a thickness direction.
65, 66 and 67 are joined. The tuning fork arms 60 and 61 are caused to vibrate by applying an alternating voltage to the piezoelectric ceramic thin plates 64 and 65. When the vibrating gyroscope is rotated about the axis 68 in this state, a force is generated in a direction perpendicular to the vibration direction of the tuning fork arms 60 and 61 by the action of the Coriolis force, and this force causes the vibrating sound pieces 62 and 63 to move. Vibrate. As a result, a voltage proportional to the rotational angular velocity is generated on the piezoelectric ceramic thin plates 66 and 67.

[0004]

However, in the above-mentioned conventional vibrating gyroscope, the tuning fork arm, the vibrating sound piece and the piezoelectric ceramic thin plate are bonded by using an adhesive, so that the bonding position varies or the adhesive layer varies. Etc.
There was a problem that the characteristics of the vibrating gyroscope fluctuated.

Further, the vibrating sound pieces 62 and 63 are connected to the tuning fork arm 6.
There is a problem that it is necessary to join at right angles to 0 and 61, which is a very difficult process.

In addition, there is a problem that the temperature characteristics are poor because the piezoelectric ceramic is used.

[0007] In addition, there is a problem that the entire structure becomes large due to the two-story structure of the tuning fork arm and the vibrating reed.

Accordingly, the present invention is to solve such a problem, and it is an object of the present invention to provide an inexpensive and highly reliable vibration gyro having a simple structure.

[0009]

According to a first aspect of the present invention, there is provided a vibrating gyroscope having a tuning fork shape having two arms made of a piezoelectric material. A detection electrode for detecting an angular velocity is provided at a position which has electrodes and is opposed to and close to an arm vibration surface which is the same as a plane including the two arms.

Therefore, there is no variation in characteristics due to the adhesion of the piezoelectric ceramic or the joining of the vibrating sound piece, and the manufacturing process is simple, so that an inexpensive and reliable vibration gyroscope can be provided.

(2) The vibratory gyroscope according to claim 2 is claim 1.
3. The vibrating gyroscope according to claim 1, wherein the piezoelectric material is quartz.

Therefore, a vibrating gyroscope having good temperature characteristics can be provided.

(3) The vibrating gyroscope according to the third aspect of the present invention is the tuning fork type vibrating gyroscope according to the first aspect, wherein the detecting electrode for detecting the angular velocity is formed on an inner surface of a holding case of the vibrating gyroscope having a tuning fork shape made of the piezoelectric material. It is characterized by doing.

Therefore, it is possible to provide a very small vibration gyro including the package.

According to a fourth aspect of the present invention, there is provided a vibration gyro according to the third aspect, wherein the drive electrode on the arm and the detection electrode formed on the inner surface of the case are provided on the arm support portion of the tuning fork type vibration gyro. Characterized in that a step is provided to secure a gap between the two.

Therefore, the interval between the two electrodes can be secured with high accuracy, and the angular velocity can be detected with high accuracy.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments.

(Embodiment 1) FIG. 1 is a schematic view of a vibrating gyroscope according to Embodiment 1, and FIGS. 2 and 3 show the operation thereof.

In FIG. 1, a tuning fork type vibration gyro 100 is shown.
Are the two arms 110 and 120 and the arm support 13
It is composed of 0. As shown in FIGS. 1 to 3, drive electrodes 111, 112, 113 for vibrating the arms 110 and 120 in the directions of arrows 150 and 151 in the X-Z plane are provided on the side surfaces. , 114, 121,
122, 123, and 124 are formed.

The driving electrodes 111, 112 and 12
Detection electrodes 142, 141, 144, and 143 for detecting angular velocity are formed at positions close to and in proximity to 1, 122.

The operation of the tuning fork type vibrating gyroscope 100 will now be described with reference to FIGS. By applying an alternating voltage to the driving electrodes, the tuning fork type vibrating gyroscope 10
The two arms 110 and 120 in the stationary state move away from each other (in the direction of arrow 150) as shown in FIGS. 2 (a) to 2 (b) and 2 (c), and approach each other in the next half cycle. (Direction of arrow 151).

As shown in FIG. 3B, when the tuning fork type vibrating gyroscope 100 is rotated about the Z axis in the direction of arrow 160, when the arms 110 and 120 are displaced in the direction of arrow 150, Coriolis forces 170, 171 act on the arms 110, 120, and the arms 110, 1
20 are respectively displaced in the direction of the Coriolis force. Therefore, the drive electrodes 112 and 121 and the detection electrodes 141 and 1
44 approach each other, and the drive electrodes 111 and 122 and the detection electrodes 142 and 143 move away. FIG. 3 (c)
As shown in FIG.
When moving in the direction of
3B, Coriolis forces 180 and 181 opposite to those in FIG. 3B act, and the arms 110 and 120 are displaced in the direction opposite to that in FIG. The Coriolis force is proportional to the rotation speed around the Z axis. Therefore, when the Coriolis force changes according to the rotational angular velocity and direction about the Z axis, the distance between the drive electrode and the detection electrode changes. Therefore, the angular velocity can be accurately detected by electrically detecting the change in capacitance between the two electrodes.

Further, by using quartz as a piezoelectric material in the tuning fork type vibration gyro of the present invention, the resonance frequency fluctuation of the vibration due to the ambient temperature is small, so that a tuning fork type vibration gyro having good temperature characteristics can be realized. I can do it.

FIG. 4 is a sectional view including a holding case of the tuning fork type vibrating gyroscope 100. The tuning fork type vibrating gyroscope 100 is fixed and sealed by a case main body 190 and a lid 200 for holding.

On the case 190 and the lid 200, detection electrodes 141, 142, 143, 144 are formed at positions facing the drive electrodes 112, 111, 122, 121.

Therefore, a small and thin tuning-fork type vibrating gyroscope including a package can be realized.

(Embodiment 2) FIG. 5 is a plan view and a sectional view of a tuning fork type vibrating gyroscope according to Embodiment 2. The arm supporting portion 130 of the tuning fork type vibrating gyroscope 100 is provided with a step portion 300 for securing a gap between the drive electrode on the arm and the detection electrode formed on the case body and the lid. Since the tuning fork type vibrating gyroscope 100 can be made by fine processing such as etching, the step can be formed with high accuracy. Therefore, the gap between the drive electrode and the detection electrode can be accurately formed, so that the angular velocity can be accurately detected.

[0028]

As described above, the present invention has the following effects.

First, according to the first aspect of the present invention, since there is no step of bonding the piezoelectric ceramic and the diaphragm, it is possible to manufacture the gyro with high accuracy and low cost, and to provide a highly reliable tuning fork type vibrating gyroscope. Can do things.

According to the second aspect of the present invention, by using quartz as the piezoelectric material, a resonance frequency fluctuation of vibration due to a change in ambient temperature is small, and therefore a tuning fork type vibration gyro having good temperature characteristics is realized. can do. Further, since the arm shape and the drive electrode can be manufactured by the photolithography technology and the etching technology, they can be manufactured accurately and at low cost, and a highly accurate and highly reliable tuning fork type vibration gyro can be provided.

According to the third aspect of the present invention, since the angular velocity is detected by the electrodes on the side surfaces of the arm and the electrodes formed on the inner surface of the holding case, a small and thin tuning-fork type vibrating gyroscope including a package is provided. Can be realized.

According to the fourth aspect of the present invention, a step for securing a gap between the electrode on the arm and the detection electrode formed on the inner surface of the case is formed in the arm support by fine processing such as etching. Thus, a gap between the two electrodes can be secured with high accuracy, and thus a tuning fork type vibration gyro with high angular velocity accuracy can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a tuning fork type vibration gyro according to a first embodiment.

FIG. 2 is an explanatory diagram of an operation of the tuning fork type vibration gyro according to the first embodiment.

FIG. 3 is an operation explanatory diagram of the tuning fork type vibration gyro according to the first embodiment.

FIG. 4 is a sectional view of a unit of the tuning fork type vibration gyro according to the first embodiment.

5A and 5B are a plan view and a cross-sectional view of a tuning fork type vibration gyro according to a second embodiment.

FIG. 6 is a schematic diagram of a conventional vibrating gyroscope.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Tuning fork vibrating gyroscope 110, 120 Arm 111-114 Drive electrode 121-124 Drive electrode 140 Substrate 141-144 Detection electrode 150, 151 Arm vibration direction 160 Rotation direction 170, 171 Coriolis force direction 180, 181 Coriolis force direction 190 Case 200 Lid 300 Step

Claims (4)

[Claims] 1. A tuning fork-shaped vibrating gyroscope having two arms made of a piezoelectric material, wherein a driving electrode for driving the arm is provided on a side surface of the two arms, and a plane including the two arms is provided. Opposing the arm vibration surface which is the same surface,
A tuning fork type vibrating gyroscope, wherein a detecting electrode for detecting an angular velocity is provided at a position close to the vibrating gyroscope. 2. The tuning fork type vibration gyro according to claim 1, wherein said piezoelectric material is quartz. 3. The tuning fork type vibration gyro according to claim 1, wherein said detection electrode is formed on an inner surface of a holding case of the tuning fork-shaped vibration gyro made of said piezoelectric material. 4. A tuning fork type vibration gyro according to claim 3, wherein a step for securing a gap between a drive electrode on said arm and a detection electrode formed on the inner surface of the case is formed in an arm support portion of said tuning fork type vibration gyro. A tuning fork-type vibrating gyro characterized by being provided.