Vibrator, vibratory gyroscope, and linear accelerometer

• US 6,046,531 A
• Filed: 07/01/1998
• Issued: 04/04/2000
• Est. Priority Date: 07/04/1997
• Status: Expired due to Term

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Soma, Takao, Kikuchi, Takayuki, Osugi, Yukihisa, Gouji, Shosaku
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US09/108,500
• Time in Patent Office: 643 Days
• Field of Search: 310/328, 310/339, 310/367, 310/311, 310/361, 310/370, 73/504.03, 73/504.16, 73/514.15, 73/514.34
• US Class Current: 310/367
• CPC Class Codes: G01C 19/5621 the devices involving a micromechanical structure

Abstract

A vibrator comprising a base part at least one of whose ends is fixed, a first leg extending in a direction crossing this base part, a second leg extending in a direction crossing the base part and being opposed to said first leg with respect to said base part, a first bending-vibration piece extending in a direction crossing said first leg, a second bending-vibration piece extending in a direction crossing the first leg and being opposite to said first bending-vibration piece with respect to said first leg, a third bending-vibration piece extending in a direction crossing said second leg, and a fourth bending-vibration piece extending in a direction crossing the second leg and being opposite to said third bending-vibration piece with respect to said second leg.

Claims

1. A single crystal vibrator, comprising:

a base part including a fixed end,

a first leg extending in a direction crossing said base part,

a second leg extending in a direction crossing said base part and being opposed to said first leg with respect to said base part, said first and second legs being joined with said base part at an intersecting part,

a first bending-vibration piece extending in a direction crossing said first leg,

a second bending-vibration piee extending in a direction crossing said first leg and being opposite to said first bending-vibration piece with respect to said first leg,

a third bending-vibration piece extending in a direction crossing said second leg,

a fourth bending-vibration piece extending in a direction crossing said second leg and being opposite to said third bending-vibration piece with respect to said second leg, and

a projection part extending in a direction opposite to said base part from said intersecting part,

wherein said base part, said first and second legs, said first, second, third and fourth bending-vibration pieces, and said projection part all are substantially planar and lie in the same plane.

2. A vibrator as defined in claim 1, wherein:

vibrations of said first bending-vibration piece and said second bending-vibration piece are symmetrical in phase to each other with respect to said first leg, and vibrations of said third bending-vibration piece and said fourth bending-vibration piece are symmetrical in phase to each other with respect to said second leg.

3. A vibrator as defined in claim 2, wherein:

the center of gravity in a vibration of the whole vibration system comprising said first bending-vibration piece and said second bending-vibration piece is on said first leg or on an extension line thereof, and the center of gravity in a vibration of the whole vibrating system comprising said third bending-vibration piece and said fourth bending-vibration piece is on said second leg or on an extension line thereof.

4. A vibrator as defined in claim 1, wherein:

a vibration of the center of gravity in a vibration of the whole vibration system comprising said first leg, said first bending-vibration piece and said second bending-vibration piece and the center of gravity in a vibration of the whole vibration system said second leg, said third bending-vibration piece and said fourth bending-vibration piece are symmetrical in phase to each other with respect to said base part.

5. A vibrator as defined in claim 4, wherein:

a stress applied to said base part by a vibration of the whole vibration system comprising said first leg, said first bending-vibration piece and said second bending-vibration piece and a stress applied to said base part by a vibration of the whole vibration system comprising said second leg, said third bending-vibration piece and said fourth bending-vibration piece offset each other in said base part.

6. A vibrator as defined in claim 4, wherein:

the center of gravity in a vibration of the whole vibration system comprising said first leg, said first bending-vibration piece, said second bending-vibration piece, said second leg, said third bending-vibration piece, and said fourth bending-vibration piece is on said base part or on an extension line thereof.

7. A vibrator as defined in claim 5, wherein:

the center of gravity in a vibration of the whole vibration system comprising said first leg, said first bending-vibration piece, said second bending-vibration piece, said second leg, said third bending-vibration piece, and said fourth bending-vibration piece is on said base part or on an extension line thereof.

8. A linear accelerometer for detecting a linear acceleration, comprising:

a vibrator as defined in claim 1, and

detecting means for detecting deformation of said vibrator generated by a Newton force applied to said vibrator when a linear acceleration is applied to said vibrator.

9. A vibrator as defined in claim 1, further comprising:

a fixing part for fixing said fixed end of said base part, and first and second resonant arms protecting from said fixing part for resonating with a vibration of said base part.

10. A vibrator as defined in claim 9, wherein:

the projecting dimensions of both sides of each of said first and second resonant arms from the base part are different from each other.

11. A vibrator as defined in claim 1, wherein a through hole is formed in each of the bending-vibration pieces, extending in a longitudinal direction of said bending-vibration piece.

12. A vibrator as defined in claim 9, wherein:

a through hole is formed in each of said first and second resonant arms, extending in a longitudinal direction thereof.

13. A vibrator as defined in claim 1, wherein:

a fixing part is provided for fixing said fixed end,

said fixing part includes fixed ends, and

said base part is provided on one side of said fixing part, and resonant arms are provided on the other side of said fixing part.

14. A vibrator as defined in claim 9, wherein:

said fixing part includes fixed ends, and

said base part is provided on one side of said fixing part, and resonant arms are provided on the other side of said fixing part.

15. A vibratory gyroscope for detecting a turning angular velocity comprising a vibrator as defined in claim 1, further comprising:

exciting means for exciting a vibration in a specific plane in said vibrator; and

detecting means for detecting a bending vibration of said vibrator generated by a Coriolis force applied to said vibrator when said vibrator is turned in said specific plane and outputting a signal according to said bending vibration.

16. A vibratory gyroscope for detecting a turning angular velocity, as defined in claim 15, wherein:

said exciting means comprises means for exciting a bending vibration in each of said first bending-vibration piece, said second bending-vibration piece, said third bending-vibration piece and said fourth bending-vibration piece, and said detecting means comprises means for detecting a bending vibration in said base part generated by a Coriolis force applied to said vibrator when said vibrator is turned in said specific plane and outputting a signal according to said bending vibration.

17. A vibratory gyroscope for detecting a turning angular velocity, comprising:

a vibrator as defined in claim 9,

exciting means for exciting a bending vibration in each of said first bending-vibration piece, said second bending-vibration piece, said third bending-vibration piece and fourth bending-vibration piece, and

detecting means for detecting a bending vibration in one of said first and second resonant arms generated by a Coriolis force applied to said vibrator when said vibrator is turned in said specific plane and outputting a signal according to said bending vibration.

18. A vibratory gyroscope for detecting a turning angular velocity, comprising:

a vibrator as defined in claim 13,

exciting means for exciting a bending vibration in each of said first bending-vibration piece, said second bending-vibration piece, said third bending-vibration piece and said fourth bending-vibration piece, and

detecting means for detecting a bending vibration in said resonant arm generated by a Coriolis force applied to said vibrator when said vibrator is turned in said specific plane and outputting a signal according to said bending vibration.

19. A linear accelerometer for detecting a linear acceleration, comprising:

a vibrator as defined in one of claim 9, and

detecting means for detecting deformation of said vibrator generated by a Newton force applied to said vibrator when a linear acceleration is applied to said vibrator.

20. A linear accelerometer for detecting a linear acceleration, comprising:

a vibrator as defined in one of claim 13, and

detecting means for detecting deformation of said vibrator generated by a Newton force applied to said vibrator when a linear acceleration is applied to said vibrator.

21. A single crystal vibrator, comprising:

a fixing part having fixed ends,

a base part including a fixed end connected to a first side of said fixing part,

a first leg extending in a direction crossing said base part,

a second leg extending in a direction crossing said base part and being opposed to said first leg with respect to said base part,

a first bending-vibration piece extending in a direction crossing said first leg,

a second bending-vibration piece extending in a direction crossing said first leg and being opposite to said first bending-vibration piece with respect to said first leg,

a third bending-vibration piece extending in a direction crossing said second leg,

a fourth bending-vibration piece extending in a direction crossing said second leg and being opposite to said third bending-vibration piece with respect to said second leg, and

resonant arms connected to a second side of said fixing part.

22. A single crystal vibrator, comprising:

a base part including a fixed end,

a first leg extending in a direction crossing said base part,

a second leg extending in a direction crossing said base part and being opposite to said first leg with respect to said base part, said first and second legs being joined with said base part at an intersecting part,

a first vibration system provided on one side of said first leg,

a second vibration system provided on the other side of said first leg,

a third vibration system provided on one side of said second leg,

a fourth vibration system provided on the other side of said second leg, and

a projection part extending in a direction opposite to said base part from said intersecting part,

wherein (i) a vibration of the center of gravity of said first vibration system is symmetrical in phase to a vibration of the center of gravity of said second vibration system with respect to said first leg, (ii) a vibration of the center of gravity of said third vibration system is symmetrical in phase to a vibration of the center of gravity of said fourth vibration system with respect to said second leg, and (iii) said base part, said first and second legs, said first, second, third and fourth bending-vibration systems, and said projection part all are substantially planar and lie in the same plane.

23. A vibrator as defined in claim 22, wherein:

the center of gravity in a vibration of the whole vibration system comprising said first vibration system and said second vibration system is on said first leg or on an extension line thereof, and the center of gravity in a vibration of the whole vibration system comprising said third vibration system and said fourth vibration system is on said second leg or on an extension line thereof.

24. A vibrator as defined in claim 22, wherein:

a vibration of the center of gravity in a vibration of the whole vibration system comprising said first leg, said first vibration system and said second vibration system, is symmetrical in phase to a vibration of the center of gravity in a vibration of the whole vibration system comprising said second leg, said third vibration system and said fourth vibration system with respect to said base part.

25. A vibrator as defined in claim 24, wherein:

a stress applied to said base part by a vibration of the whole vibration system comprising said first leg, said first vibration system and said second vibration system and a stress applied to said base part by a vibration of the whole vibration system comprising said second leg, said third vibration system and said fourth vibration system offset each other in said base part.

26. A vibrator as defined in claim 24, wherein:

the center of gravity in a vibration of the whole vibration system comprising said first leg, said first vibration system, said second vibration system, said second leg, said third vibration system and said fourth vibration system is on said base part or on an extension line thereof.

27. A vibrator as defined in one of claims 22, wherein said first vibration system is a first bending-vibration piece extending in a direction crossing said first leg, said second vibration system is a second bending-vibration piece extending in a direction crossing said first leg and being opposite to said first bending-vibration piece with respect to said first leg, said third vibration system is a third bending-vibration piece extending in a direction crossing said second leg, and said fourth vibration system is a fourth bending-vibration piece extending in a direction crossing said second leg and being opposite to said third bending-vibration piece with said second leg as an axis.

28. A single crystal vibrator, comprising:

a base part including a fixed end,

a first leg extending in a direction crossing said base part,

a second leg extending in a direction crossing said base part and being opposite to said first leg with said base part as an axis, said first and second legs being joined with said base part at an intersecting part,

a first vibration system provided on one side of said first leg,

a second vibration system provided on the other side of said first leg,

a third vibration system provided on one side of said second leg,

a fourth vibration system provided on the other side of said second leg, and

a projection part extending in a direction opposite to said base part from said intersecting part,

wherein (i) a vibration of the center of gravity in a vibration of the whole vibration system comprising said first leg, said first vibration system and said second vibration system is symmetrical in phase to a vibration of the center of gravity in a vibration of the whole vibration system comprising said second leg, said third vibration system and said fourth vibration system with respect to said base part, and (ii) said base part, said first and second legs, said first, second, third and fourth bending-vibration systems, and said projection part all are substantially planar and lie in the same plane.

29. A vibrator as defined in claim 28, wherein:

a stress applied to said base part by a vibration of the whole vibration system comprising said first leg, said first vibration system and said second vibration system and a stress applied to said base part by a vibration of the whole vibration system comprising said leg, said third vibration system and said fourth vibration system offset each other in said base part.

30. A vibrator as defined in claim 28, wherein:

the center of gravity in a vibration of the whole vibration system comprising said first leg, said first vibration system, said second vibration system, said second leg, said third vibration system and said fourth vibration system is on said base part or on an extension line thereof.

31. A vibrator as defined in claim 28, wherein:

a vibration of the center of gravity of said first vibration system is symmetrical in phase to a vibration of the center of gravity of said second vibration system with respect to said first leg, and a vibration of the center of gravity of said third vibration system is symmetrical in phase to a vibration of the center of gravity of said fourth vibration system with respect to said second leg.

32. A vibrator, comprising:

a fixing part,

a base part including a fixed end connected to said fixing part,

a first leg extending in a direction crossing said base part,

a second leg extending in a direction crossing said base part and being opposed to said first leg with respect to said base part,

a first bending-vibration piece extending in a direction crossing said first leg,

a second bending-vibration piece extending in a direction crossing said first leg and being opposite to said first bending-vibration piece with respect to said first leg,

a third bending-vibration piece extending in a direction crossing said second leg,

a fourth bending-vibration piece extending in a direction crossing said second leg and being opposite to said third bending-vibration piece with respect to said second leg, and

first and second resonant arms projecting from said fixing part and resonating with vibration of said base part.

33. A vibrator, comprising:

a base part including a fixed end,

a first leg extending in a direction crossing said base part,

a second leg extending in a direction crossing said base part and being opposed to said first leg with respect to said base part,

a first bending-vibration piece extending in a direction crossing said first leg,

a second bending-vibration piece extending in a direction crossing said first leg and being opposite to said first bending-vibration piece with respect to said first leg,

a third bending-vibration piece extending in a direction crossing said second leg, and

a fourth bending-vibration piece extending in a direction crossing said second leg and being opposite to said third bending-vibration piece with respect to said second leg,

wherein a through hole is formed in each of the bending-vibration pieces, extending in a longitudinal direction of said bending-vibration pieces.