Angular rate detecting device

• US 5,038,613 A
• Filed: 05/21/1990
• Issued: 08/13/1991
• Est. Priority Date: 05/19/1989
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ichinose, Toshihiko, Manabe, Takahiro, Terada, Jiro, Takenaka, Hiroshi, Ueda, Kazumitsu, Senda, Hiroshi, Nozu, Mikio, Osada, Yasuhito
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US07/526,027
• Time in Patent Office: 449 Days
• Field of Search: 73/493, 73/505, 73/510, 73/431
• 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

Abstract

An angular rate sensor detects an angular rate which is produced when a mobile body such as a motor vehicle moves. The angular rate detecting device comprises at least two angular rate sensors housed in a case perpendicularly to each other. Each angular rate sensor comprises a pair of vibratory units which are interconnected by a connector in a tuning-fork configuration. The vibratory units of different angular rate sensors are vibrated at different frequencies. The angular rate sensors may be accommodated in a damper block, which may be housed in the case. Since the angular rate sensors are housed in the single case, the angular rate detecting device is compact in structure and small in size. With the angular rate sensors accommodated in the damper block, they are protected from resonance, crosstalk interferences, and noise, and hence can produce reliable detected output signals.

Claims

1. An angular rate detecting device comprising:

at least two angular rate sensors, each comprising a first vibratory unit including a first piezoelectric drive element and a first piezoelectric detection element which are joined to each other in orthogonal planes, respectively, and a second vibratory unit including a second piezoelectric drive element and a second piezoelectric detection element which are joined to each other in orthogonal planes, respectively, said first and second vibratory units extending parallel to a detection axis;

a connector interconnecting ends of said first and second piezoelectric drive elements in a tuning-fork structure;

a case housing said angular rate sensors perpendicularly to each other; and

means for vibrating said first vibratory units of the angular rate sensors at different frequencies.

2. An angular rate detecting device according to claim 1, wherein each of said first and second piezoelectric drive elements and said first and second piezoelectric detection elements is of a bimorph structure.

3. An angular rate detecting device according to claim 1, further comprising means for applying a signal to said first piezoelectric drive element to vibrate said first vibratory unit for thereby causing said second vibratory unit to vibrate due to tuning-fork vibration, means for detecting electric charges produced on said second piezoelectric drive element by the vibration of said second vibratory unit, and means for controlling said signal applied to said first piezoelectric drive element so that the detected electric charges will be of a constant amplitude.

4. An angular rate detecting device comprising:

at least two angular rate sensors, each comprising a first vibratory unit including a first piezoelectric bimorph drive element and a first piezoelectric bimorph detection element which are joined to each other in orthogonal planes, respectively, and a second vibratory unit including a second piezoelectric bimorph drive element and a second piezoelectric bimorph detection element which are joined to each other in orthogonal planes, respectively, said first and second vibratory units extending parallel to a detection axis;

a connector interconnecting ends of said first and second piezoelectric drive elements in a tuning-fork structure;

a damper block accommodating therein said angular rate sensors perpendicularly to each other;

a metallic casing housing said damper block; and

means for vibrating said first vibratory units of the angular rate sensors at a different frequencies.