Angular velocity and acceleration sensor

• US 4,750,364 A
• Filed: 10/20/1986
• Issued: 06/14/1988
• Est. Priority Date: 10/21/1985
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Sato, Kazuo, Tanaka, Shinji, Terasawa, Tsuneo, Kawamura, Yoshio
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US06/920,426
• Time in Patent Office: 603 Days
• Field of Search: 73/505, 73/510, 73/517 AV, 73/517 R, 331/156
• US Class Current: 73/510
• CPC Class Codes: G01C 19/5607 using vibrating tuning forks double-ended tuning forks using planar vibrating masses suspended at opposite ends G01C19/5719
• CPC Class Codes: G01P 15/097 by vibratory elements
• CPC Class Codes: G01P 15/14 by making use of gyroscopes gyroscopes per se G01C19/00

Abstract

The specification discloses an angular velocity and acceleration sensor in which a tuning-fork oscillator is vibrated on the main driven vibrating axis and displacement on an axis which is parallel to the main driven vibrating axis or displacement which crosses it at right angles is detected so that at least one of angular velocity and acceleration on an axis which is parallel to the main driven vibrating axis or which crosses it at right angles may be detected. The sensor is characterized in that vibrating reeds of the tuning-fork oscillator are so formed that the spring constant of the vibrating reeds on the main driven vibrating axis is substantially equal to that on the axis which crosses the main driven vibrating axis at right angles.

Claims

1. An angular velocity and acceleration sensor in which a tuning-fork oscillator is vibrated on the main driven vibrating axis and displacement which crosses said main driven vibration axis at right angles is detected so that at least one of angular velocity and acceleration which crosses said main driven vibrating axis at right angles may be detected, said sensor comprising:

a vacuum vessel in which said tuning-fork oscillator is mounted for operation in a vacuum environment;

vibrating reeds associated with said tuning-fork oscillator formed so that the spring constant of said vibrating reeds on said main driven vibrating axis is substantially equal to that on the axis which crosses said main driven vibrating axis at right angles, said vibrating reeds having flat elements each with flat surfaces that are parallel to the main driven vibrating axis;

said flat elements being integrally formed on said material as part of said vibrating reeds and located at the ends of said vibrating reeds; and

means including a pair of driven electrodes for driving said tuning-fork oscillator positioned on opposite sides of said flat elements in parallel to said main driven vibrating axis and facing the flat surfaces of said flat elements.

2. An angular velocity and acceleration sensor according to claim 1, in which said vibrating reeds are made from one material selected from the group consisting of single crystal Si, a metal, GaAs, and piezoelectric materials.

3. An angular velocity and acceleration sensor according to claim 1, in which said vibrating reeds are made of a single crystal of Si.

4. An angular velocity and acceleration sensor according to claim 1, in which said vibrating reeds are made of a single crystal of metal.

5. An angular velocity and accelerating sensor according to claim 1, in which said vibrating reeds are made of a single crystal or GaAs.

6. An angular velocity and accelerating sensor according to claim 1, in which said vibrating reeds are made of a single crystal having piezoelectric properties.

7. An angular velocity and acceleration sensor according to claim 1, further comprising a plurality of pairs of detection electrodes located at both sides of said flat elements, said electrodes having flat surfaces that are parallel to said driven vibrating axis and means mounting each pair of detection electrodes flat surfaces to be on opposite sides of and to face the respective flat surfaces of each of said flat elements.

8. An angular velocity and acceleration sensor according to claim 7, wherein the outer ends of said flat elements are located between a respective pair of said detection electrodes whereby displacement of said flat elements that is on an axis which is parallel to said main driven vibration axis is detected so that a signal related to acceleration on an axis which is parallel to said main driven vibrating axis is provided.