Vibrator, vibratory gyroscope, and vibration adjusting method

• US 6,018,212 A
• Filed: 12/15/1997
• Issued: 01/25/2000
• Est. Priority Date: 11/26/1996
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: NGK Insulators Limited
• Inventors: Soma, Takao, Kikuchi, Takayuki, Osugi, Yukihisa, Gouji, Shosaku
• Primary Examiner(s): Budd, Mark O.
• Application Number:
  US08/991,011
• Time in Patent Office: 771 Days
• Field of Search: 310/316, 310/321, 310/366, 310/367, 310/370, 73/505
• US Class Current: 310/321
• 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

A vibrator of a vibratory gyroscope comprises a main arm having a base part and at least one bending-vibration piece extending from the base part in a direction crossing the longitudinal direction of the base part and a fixing part for fixing one end of the base part, and the base part and the bending-vibration piece are formed so as to extend substantially in a specified plane. Preferably, at the opposite side to one end of the base part, a projection projecting from the bending-vibration piece is provided, or at least a pair of resonant arms resonating with vibration of the base part, said pair of resonant arms projecting from the fixing part are provided. Thanks to this, it has been possible to detect a turning angular rate in a sufficiently high accuracy without providing a projection which has a certain weight and extends from the vibrator toward the axis of turning even in case of arranging the vibrator so that the vibration arm of the vibrator extends perpendicularly to the axis of turning.

Claims

1. A vibrator comprising:

a fixing part arranged in a plane;

a base part arranged in said plane and having a first end attached to said fixing part and a free second end distal from said first end in a longitudinal direction of said base part;

a substantially straight bending vibration piece arranged in said plane and having a first end attached to a portion of said base part other than said first end of said base part, and a second end distal from said first end in a longitudinal direction of said bending vibration piece, the longitudinal direction of said bending vibration piece intersecting the longitudinal direction of said base part at an angle of 45°

to 135°

; and

excitation means for vibrating at least one of said base part and said bending vibration piece;

wherein said bending vibration piece terminates at said second end thereof, and said base part and said bending vibration piece both vibrate in a bending vibration mode substantially within said plane using said first ends thereof, respectively, as their fulcrum.

2. The vibrator of claim 1, wherein said first end of said bending vibration piece is attached to said base part at said second end thereof.

3. The vibrator of claim 2, wherein said bending vibration piece comprises a pair of pieces, the first end of each piece being attached to said base part at said second end thereof so that said bending vibration pieces are symmetrical about a longitudinal axis of said base part.

4. The vibrator of claim 2, further comprising a projection piece arranged within said plane and extending from said second end of said base part in a direction substantially parallel with a longitudinal axis of said base part.

5. The vibrator of claim 3, further comprising a projection piece arranged within said plane and extending from said second end of said base part in a direction substantially parallel with a longitudinal axis of said base part.

6. The vibrator of claim 1, further comprising at least one pair of resonant arms arranged within said plane and extending from said fixing part, wherein said resonant arms resonate with vibration of said base part.

7. The vibrator of claim 6, wherein said resonant arms extend substantially parallel to said base part.

8. The vibrator of claim 7, wherein portions of said fixing part positioned between said base part and said resonant arms extend along said base part and said resonant arms a predetermined distance beyond a remaining portion of said fixing part.

9. The vibrator of claim 8, wherein said predetermined distance ranges from 1.0 mm to 6.0 mm.

10. The vibrator of claim 1, wherein said bending vibration piece has a through hole passing therethrough in a direction substantially perpendicular to said plane.

11. The vibrator of claim 6, wherein each of said resonant arms has a through hole passing therethrough in a direction substantially perpendicular to said plane.

12. The vibrator of claim 1, wherein said base part extends in a first direction away from said fixing part, and said vibrator further comprises a resonant arm arranged in said plane and extending in a second direction, diametrically opposed to said first direction, away from said fixing part.

13. The vibrator of claim 2, wherein said base part extends in a first direction away from said fixing part, and said vibrator further comprises a resonant arm arranged in said plane and extending in a second direction, diametrically opposed to said first direction, away from said fixing part.

14. The vibrator of claim 3, wherein said base part extends in a first direction away from said fixing part, and said vibrator further comprises a resonant arm arranged in said plane and extending in a second direction, diametrically opposed to said first direction, away from said fixing part.

15. The vibrator of claim 12, further comprising a pair of resonant arms arranged in said plane and extending in said first direction.

16. The vibrator of claim 13, further comprising a pair of resonant arms arranged in said plane and extending in said first direction.

17. The vibrator of claim 14, further comprising a pair of resonant arms arranged in said plane and extending in said first direction.

18. The vibrator of claim 1, wherein the longitudinal direction of said bending vibration piece intersects the longitudinal direction of said base part at an angle of about 90°

.

19. The vibrator of claim 1, wherein said excitation means comprises at least one driving electrode positioned on said base part.

20. The vibrator of claim 19, further comprising detecting electrodes positioned on said bending vibration piece.

21. The vibrator of claim 1, wherein said excitation means comprises at least one driving electrode positioned on said bending vibration piece.

22. The vibrator of claim 21, further comprising detecting electrodes positioned on said base part.

23. The vibrator of claim 12, wherein said excitation means comprises at least one driving electrode positioned on said resonant arm.

24. The vibrator of claim 23, further comprising detecting electrodes positioned on said bending vibration piece.

25. The vibrator of claim 12, wherein said excitation means comprises at least one driving electrode positioned on said bending vibration piece.

26. The vibrator of claim 25, further comprising detecting electrodes positioned on said resonant arm.

27. The vibrator of claim 6, wherein said excitation means comprises driving electrodes positioned on said resonant arms.

28. The vibrator of claim 27, further comprising detecting electrodes positioned on said bending vibration piece.

29. The vibrator of claim 6, wherein said excitation means comprises at least one driving electrode positioned on said bending vibration piece.

30. The vibrator of claim 29, further comprising detecting electrodes positioned on said resonant arms.

61. The vibrator of claim 1, wherein said base part comprises first and second base parts, each having a first end attached to said fixing part and a free second end distal from said first end in a longitudinal direction of said base part, and wherein said first end of said bending vibration piece is attached to said second end of said first base part and said second end of said bending vibration piece is attached to said second end of said second base part.

31. A vibrator comprising:

a fixing part arranged in a plane;

a base part arranged in said plane and having a first end attached to said fixing part and a free second end distal from said first end in a longitudinal direction of said base part;

a substantially straight bending vibration piece arranged in said plane and having a first end attached to a portion of said base part other than said first end of said base part, and a free second end distal from said first end in a longitudinal direction of said bending vibration piece, the longitudinal direction of said bending vibration piece intersecting the longitudinal direction of said base part at an angle of 45°

to 135°

; and

excitation means for vibrating at least one of said base part and said bending vibration piece;

wherein said base part and said bending vibration piece both vibrate in a bending vibration mode substantially within said plane using said first ends thereof, respectively, as their fulcrum.

32. The vibrator of claim 31, wherein said first end of said bending vibration piece is attached to said base part at said second end thereof.

33. The vibrator of claim 32, wherein said bending vibration piece comprises a pair of pieces, the first end of each piece being attached to said base part at said second end thereof so that said bending vibration pieces are symmetrical about a longitudinal axis of said base part.

34. The vibrator of claim 32, further comprising a projection piece arranged within said plane and extending from said second end of said base part in a direction substantially parallel with a longitudinal axis of said base part.

35. The vibrator of claim 33, further comprising a projection piece arranged within said plane and extending from said second end of said base part in a direction substantially parallel with a longitudinal axis of said base part.

36. The vibrator of claim 31, further comprising at least one pair of resonant arms arranged within said plane and extending from said fixing part, wherein said resonant arms resonate with vibration of said base part.

37. The vibrator of claim 36, wherein said resonant arms extend substantially parallel to said base part.

38. The vibrator of claim 37, wherein portions of said fixing part positioned between said base part and said resonant arms extend along said base part and said resonant arms a predetermined distance beyond a remaining portion of said fixing part.

39. The vibrator of claim 38, wherein said predetermined distance ranges from 1.0 mm to 6.0 mm.

40. The vibrator of claim 31, wherein said bending vibration piece has a through hole passing therethrough in a direction substantially perpendicular to said plane.

41. The vibrator of claim 36, wherein each of said resonant arms has a through hole passing therethrough in a direction substantially perpendicular to said plane.

42. The vibrator of claim 31, wherein said base part extends in a first direction away from said fixing part, and said vibrator further comprises a resonant arm arranged in said plane and extending in a second direction, diametrically opposed to said first direction, away from said fixing part.

43. The vibrator of claim 32, wherein said base part extends in a first direction away from said fixing part, and said vibrator further comprises a resonant arm arranged in said plane and extending in a second direction, diametrically opposed to said first direction, away from said fixing part.

44. The vibrator of claim 33, wherein said base part extends in a first direction away from said fixing part, and said vibrator further comprises a resonant arm arranged in said plane and extending in a second direction, diametrically opposed to said first direction, away from said fixing part.

45. The vibrator of claim 42, further comprising a pair of resonant arms arranged in said plane and extending in said first direction.

46. The vibrator of claim 43, further comprising a pair of resonant arms arranged in said plane and extending in said first direction.

47. The vibrator of claim 44, further comprising a pair of resonant arms arranged in said plane and extending in said first direction.

48. The vibrator of claim 31, wherein the longitudinal direction of said bending vibration piece intersects the longitudinal direction of said base part at an angle of about 90°

.

49. The vibrator of claim 31, wherein said excitation means comprises at least one driving electrode positioned on said base part.

50. The vibrator of claim 49, further comprising detecting electrodes positioned on said bending vibration piece.

51. The vibrator of claim 31, wherein said excitation means comprises at least one driving electrode positioned on said bending vibration piece.

52. The vibrator of claim 51, further comprising detecting electrodes positioned on said base part.

53. The vibrator of claim 42, wherein said excitation means comprises at least one driving electrode positioned on said resonant arm.

54. The vibrator of claim 53, further comprising detecting electrodes positioned on said bending vibration piece.

55. The vibrator of claim 42, wherein said excitation means comprises at least one driving electrode positioned on said bending vibration piece.

56. The vibrator of claim 55, further comprising detecting electrodes positioned on said resonant arm.

57. The vibrator of claim 36, wherein said excitation means comprises driving electrodes positioned on said resonant arms.

58. The vibrator of claim 57, further comprising detecting electrodes positioned on said bending vibration piece.

59. The vibrator of claim 36, wherein said excitation means comprises at least one driving electrode positioned on said bending vibration piece.

60. The vibrator of claim 59, further comprising detecting electrodes positioned on said resonant arms.