Monolithic resonator for vibrating beam force sensors

• US 5,109,175 A
• Filed: 09/14/1990
• Issued: 04/28/1992
• Est. Priority Date: 12/21/1989
• Status: Expired due to Term

• Current Assignee: Crystal Image Company Limited
• Original Assignee: Lucas Schaevitz, Inc.
• Inventors: Albert, William C.
• Primary Examiner(s): Budd, Mark O.
• Assistant Examiner(s): Dougherty, Thomas M.
• Application Number:
  US07/582,103
• Time in Patent Office: 592 Days
• Field of Search: 310/312, 310/321, 310/323, 310/329, 73/517 AV, 73/517 R, 73/777, 73/778, 73/781, 73/DIG. 1, 73/DIG. 4
• US Class Current: 310/321
• CPC Class Codes: G01P 15/097 by vibratory elements
• CPC Class Codes: H03H 9/0595 the holder support and resonator being formed in one body

Abstract

A monolithic resonator structure for a vibrating beam force sensor, comprising an accelerometer and pressure transducer, is provided which comprises an outer structure including a mounting structure, a force transfer structure, a plurality of flexure beams extending between the mounting and force transfer structures; and an inner structure including a vibrating beam extending between the mounting structure and the force transfer structure. The monolithic resonator is non-planar in that the outer structure has a thickness greater than said inner structure.

Claims

1. A monolithic resonator for a force sensor, wherein said force sensor includes a vibrating beam, said resonator comprising:

an outer structure including a mounting structure, a force transfer structure, and at least one flexure beam extending between said mounting and force transfer structures; and

an inner structure including said vibrating beam extending between said force transfer structure and said mounting structure;

wherein said outer structure has a thickness greater than said inner structure.

2. A monolithic resonator according to claim 1 wherein said outer structure thickness is about three to about ten times the thickness of said inner structure.

3. A monolithic resonator according to claim 1, wherein said inner and outer structures lie within a common plane along one face of the resonator, and said inner and outer structure lie, respectively, within a pair of parallel planes along another face.

4. A monolithic resonator according to claim 3, wherein the resonator has a height extending in an X direction, a length extending in a Y direction, and a thickness extending in a Z direction, said X, Y, and Z directions being substantially mutually perpendicular.

5. A monolithic resonator according to claim 4, wherein said parallel planes extend in the X-Y directions.

6. A monolithic resonator according to claim 1 and further including a mounting structure appendage for attaching said resonator to an accelerometer housing.

7. A monolithic resonator according to claim 1 and further including a structure appendage for attaching a force input structure to said force transfer structure.

8. A monolithic resonator according to claim 1, wherein said at least one flexure beam is located in proximity to one end of said vibrating beam and extend substantially perpendicular thereto.

9. A monolithic resonator according to claim 1, wherein said vibrating beam extends longitudinally in the X-direction.

10. A monolithic resonator according to claim 4 wherein said force transfer structure comprises a proof mass structure and said proof mass structure extends in the X-direction less than about one half an extent in the X-direction of said mounting mass structure.

11. A monolithic resonator according to claim 8, wherein said at least one flexure beam comprises three flexure beams for load stiffness in the Z-direction and load sensitivity in the X-direction.

12. A monolithic resonator according to claim 4, wherein said mounting structures and said force transfer structure extend substantially equally in the X-direction, and wherein said at least one flexure beam is located in proximity to one end of said vibrating beam.

13. A monolithic resonator according to claim 12, wherein at least one additional flexure beam is provided between said mounting and force transfer structure in proximity to the other end of said beam.

14. A monolithic resonator as defined in claim 12 wherein alternative electrode terminations are provided on both said mounting structure and said force transfer structure.

15. A monolithic resonator as defined in claim 1 wherein alternative electrode terminations are provided on both said mounting structure and said force transfer structure.

16. A monolithic resonator as defined in claim 8 wherein said at least one flexure beam comprises a pair of vertically spaced beams.

17. A monolithic resonator comprising:

a vibrating beam;

unitary isolator mass means at either end of said beam;

isolator beams extending from each of said isolator mass means;

a mounting structure to one side of said beam, and a force transfer structure to the other side of said beam; and

at least one flexure beam extending between said mounting structure and said force transfer structure, below said vibrating beam and substantially perpendicular thereto.

18. A monolithic resonator as defined in claim 17 and further comprising at least one additional flexure beam extending between said mounting structure and said force transfer structure above said vibrating beam and substantially parallel to said flexure beams.

19. A monolithic resonator according to claim 17 and further including alternative external mount appendages and alternative electrode terminations for selective attachment of leads, the choice of termination determined by the use of the resonator as a tension or compression resonator.

20. The monolithic resonator as defined in claim 17 wherein the vibrating beam, isolator mass means and isolator beams have a first thickness, and the mounting and force transfer structures have a second thickness, said second thickness greater than said first thickness.

21. A monolithic resonator as defined in claim wherein the first thickness is within the range of from 1/3 to 1/10 said second thickness.

22. A monolithic resonator as defined in claim wherein said force transfer and mounting structures have substantially identical height dimensions.

23. A monolithic resonator comprising:

a vibrating beam;

unitary isolator mass means at either end of said beam;

isolator beams extending from each of said isolator mass means;

a mounting structure to one side of said vibrating beam, and a force transfer structure to the other side of said vibrating beam; and

at least one flexure beam extending between said mounting structure and said force transfer structure, below said vibrating beam and substantially perpendicular thereto;

wherein said vibrating beam, said isolator mass means and said isolator beams have thicknesses within the range of from 1/3 to 1/10 thicknesses of at least said mounting structure and said force transfer structure.

24. A monolithic resonator for a vibrating beam pressure transducer comprising:

an outer structure including a mounting structure, a lever arm structure and at least one flexure beam connecting said lever arm structure to said mount structure at a pivot point; and

an inner structure including a vibrating beam structure extending between said lever arm structure and said mounting structure;

means for converting fluid pressure to a force on said lever arm structure in a direction other than toward said pivot point; and

wherein said outer structure has a thickness greater than said inner structure.

25. A monolithic resonator according to claim 24 wherein said outer structure thickness is about three to about ten times the thickness of said inner structure.

26. A monolithic resonator according to claim 24, wherein said inner and outer structures lie within a common plane along one face of the resonator, and said inner and outer structure lie, respectively, within a pair of parallel planes along another face.

27. A monolithic resonator according to claim 26, wherein the resonator has a height extending in an X direction, a length extending in a Y direction, and a thickness extending in a Z direction, said X, Y, and Z directions being substantially mutually perpendicular.

28. A monolithic resonator according to claim 27, wherein said parallel planes extend in the X-Y directions.

29. A monolithic resonator according to claim 24 and further including an external mount appendage for attaching said resonator to a pressure transducer housing.

30. A monolithic resonator according to claim 24 wherein said means for converting fluid pressure comprises a bellows.

31. A monolithic resonator according to claim 24, wherein said at least one flexure beam comprises at least two flexure beams orthogonally oriented at said pivot point.

32. A monolithic resonator according to claim 24, wherein said vibrating beam structure extends longitudinally in the X-direction.

33. A monolithic resonator according to claim 27 wherein said lever arm structure includes a lever arm and a balance weight, said lever arm and said balance weight substantially equally balanced in the x and y directions about said pivot point.

34. A monolithic resonator comprising:

a vibrating beam;

unitary isolator mass means at either end of said beam;

isolator beams extending from each of said isolator mass means;

a mounting structure to one side of said beam, and a lever arm structure to the other side of said beam; and

at least one flexure beam extending between said mounting structure and said lever arm structure, below said lever arm and substantially parallel to said vibrating beam.

35. A monolithic resonator as defined in claim 34 and further comprising at least one additional flexure beam extending between said mounting structure and said lever arm structure adjacent said vibrating beam and substantially perpendicular thereto.

36. The monolithic resonator as defined in claim 34 wherein the vibrating beam, isolator mass means and isolator beams have a first thickness, and the mounting and lever arm structures have a second thickness, said second thickness is greater than said first thickness.

37. A monolithic resonator as defined in claim 36 wherein the first thickness is within the range of from 1/3 to 1/10 the second thickness.

38. A monolithic resonator comprising:

a vibrating beam;

unitary isolator mass means at either end of said beam;

isolator beams extending from each of said isolator mass means;

a mounting structure to one side of said beam, and a lever arm structure to the other side of said beam; and

at least one flexure beam extending between said mounting structure and said lever arm structure, substantially parallel to said vibrating beam;

wherein said vibrating beam, said isolator mass means and said isolator beams have thicknesses within the range of from 1/3 to 1/10 thicknesses of said mounting structure and said lever arm structure.