Angular velocity sensor having a tuning fork construction and its method of manufacture

• US 5,447,066 A
• Filed: 09/01/1993
• Issued: 09/05/1995
• Est. Priority Date: 09/01/1993
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ichinose, Toshihiko, Yoshida, Sumitake, Tamura, Masami, Terada, Jiro, Takenaka, Hiroshi, Ushihara, Masaharu
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US08/114,145
• Time in Patent Office: 734 Days
• Field of Search: 73/505, 73/510, 73/493, 310/329, 310/370, 310/321
• US Class Current: 73/504.16
• 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

The present invention relates to an angular velocity sensor utilized as a gyroscope and particularly, to a high-performance angular velocity sensor having a tuning-fork construction. The vibrator is formed of a metal base plate which is bent about 90 degrees along a center line defined by two opposite slits extending from their respective side edges to a central region of the metal base plate so that its two bent parts are orthogonal to each other. Two piezoelectric elements are bonded to the corresponding surfaces of the two parts of each vibrator which in turn serve as an actuator and a detector.

Claims

1. An angular velocity sensor comprising:

two metal base plates, each of said metal base plates having two opposite notches provided in the center thereof and extending horizontally from an edge to a center for ease of bending, an upper portion of each of said metal base plates being bent about 90 degrees from a lower portion of each of said metal base plates, so that the bent upper portion of each of said metal base plates are orthogonal to the lower portion of each of said metal base plates;

a plurality of piezoelectric elements, a piezoelectric element being bonded to a surface of each of the upper and lower portions of each metal base plates;

an electrode block coupling the lower portion of the two metal base plates to each other so as to form a tuning-fork construction; and

the piezoelectric element on the upper portion of each of said metal base plates serves as a detector and the piezoelectric element on the lower portion of each of said metal base plates serves as an actuator, wherein the two opposite notches of each of said metal base plates consist of a first notch and a second notch which extend from opposite edges of the metal base plates to a vertical center line of the metal base plates in a vertical spaced relationship,

2. The angular velocity sensor according to claim 1, wherein the two opposite notches of each of the metal base plates form first and second slits extending from opposing side edges of each of the metal base plates to a center region and are vertically spaced from each other on each of the metal base plates.

3. The angular velocity sensor according to claim 2, wherein the first and second slits of each of the metal base plates extend from the opposing side edges of each of the metal base plates to a substantially center line of each of the metal base plates.

4. The angular velocity sensor according to claim 2, wherein the first and second slits extending from the opposing side edges to the substantially center line of each of said metal base plates are substantially equal to each other in length.

5. The angular velocity sensor according to claim 4, wherein the first and second slits are horizontally extended to an overlapping distance at the center region of each of the metal base plates, which corresponds to a thickness of the metal base plates during bending.

6. An angular velocity sensor comprising:

two metal base plates, each of said metal base plates having two opposite notches provided in the center thereof and extending horizontally from an edge of each of the metal base plates to a center for ease of bending, each of said metal base plates being bent about 90 degrees so that two bent parts of each of the metal base plates are orthogonal to each other;

piezoelectric elements bonded to surfaces of the two bent parts of each of the metal base plates;

an electrode block coupling the two metal base plates with the piezoelectric elements to each other so as to form a tuning fork construction; and

said piezoelectric elements on the two bent parts of each of said metal base plates serve as an actuator and a detector, said two metal base plates being coupled at an actuator side to each other by the electrode block, the two opposite notches of the metal base plates consisting of a first slit and a second slit which extend from opposite edges of each of said metal base plates respectively to a vertical center line of each of said metal base plates in a vertical spaced relationship, wherein one side edge of each of said metal base plates where the first slit is provided is beveled to a predetermined distance and the other side edge of each of said metal base plates where the second slit is provided is beveled to a corresponding distance in order to maintain a balanced form for each of said metal base plates.

7. An angular velocity sensor comprising two vibrators, each of said vibrators consisting of a lower portion forming an actuator and an upper portion forming a detector arranged orthogonal to each other, said two vibrators being coupled to each other at each of said lower portion to form a tuning-fork structure, each of said vibrators being formed of a metal base plate which is bent about 90 degrees along a center line defined by two opposite slits extending from opposing side edges of each of said vibrators to a central region of each of said the metal base plate so that an upper part and a lower part of each of the metal base plate, separated by the center line, are orthogonal to each other, wherein piezoelectric elements are bonded to the upper part and the lower part of the metal base plate forming each of the vibrators.