Vibration gyro sensor

• US 6,240,781 B1
• Filed: 12/23/1999
• Issued: 06/05/2001
• Est. Priority Date: 10/15/1996
• Status: Expired due to Fees

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Takeuchi, Yukihisa, Namerikawa, Masahiko, Shibata, Kazuyoshi
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US09/471,993
• Time in Patent Office: 530 Days
• Field of Search: 735/041.3, 735/041.2, 735/041.4
• US Class Current: 73/504.13
• CPC Class Codes: G01C 19/5677 of essentially two-dimensional vibrators, e.g. ring-shaped vibrators

Abstract

Disclosed is a vibration gyro sensor comprising an annular frame having an approximately square planar contour with a central opening having an approximately circular planar configuration, an annular section arranged in the opening of the annular frame and having an approximately circular planar contour for constructing a vibrator, and a plurality of resilient sections which span the inner circumference of the annular frame and the outer circumference of the annular section, wherein the annular frame, the annular section, and the plurality of resilient sections are constructed by an integrated fired product made of ceramics. The vibration gyro sensor further comprises piezoelectric/electrostrictive elements (driving piezoelectric/electrostrictive elements and detecting piezoelectric/electrostrictive elements) formed on upper surfaces of the respective resilient sections. Each of the resilient sections has a thickness in its direction of height designed to be smaller than a thickness of the annular section, which is thus thin-walled so that the rigidity in the direction of vibration of the piezoelectric/electrostrictive elements is lowered to give a large amplitude of vibration caused on the annular section (vibrator).

Claims

1. A vibration gyro sensor comprising:

a support member;

an annular section for defining a vibrator, said annular section having a first thickness;

a plurality of resilient sections for resiliently coupling said annular section to said support member, at least two of said resilient sections each having a plate-shaped portion having a second thickness less than said first thickness, said thicknesses being measured in a direction parallel to an extension of the longitudinal axis of said annular section;

a first piezoelectric/electrostrictive element formed on said plate-shaped portion of one of said resilient sections; and

a second piezoelectric/electrostrictive element formed on said plate-shaped portion of another one of said resilient sections;

wherein all of said support member, said annular section, and said plurality of resilient sections constitute an integrated fired ceramic product.

2. The vibration gyro sensor according to claim 1, wherein said plurality of resilient sections are arranged at postions separated from each other by equal spacing distances and are mutually point-symmetrical respectively.

3. The vibration gyro sensor according to claim 1, wherein said first and second piezoelectric/electrostrictive elements are formed on adjacent resilient sections, said first piezoelectric/electrostrictive element is a driving element for vibrating said resilient sections and said second piezoelectric/electrostrictive element is a detecting element for detecting a strain caused by vibration generated in a direction of 45°

with respect to a direction of vibration of said resilient sections, upon rotation about the longitudinal axis of said annular section.

4. The vibration gyro sensor according to claim 3, wherein:

each of said resilient sections is constructed by a ring section having an approximately elliptical planar configuration with its minor axis directed in a radial direction with respect to the longitudinal axis of said annular section, said driving piezoelectric/electrostrictive element is formed on said plate-shaped section which spans said ring section in a direction perpendicular to said radial direction; and

said detecting piezoelectric/electrostrictive element is formed on said plate-shaped section which spans said ring section in said radial direction.

5. The vibration gyro sensor according to claim 1, wherein said support member has an approximately circular planar configuration with an outer diameter which is smaller than an inner diameter of said annular section.

6. The vibration gyro sensor according to claim 1, wherein said support member has an opening having an approximately circular planar configuration with an inner diameter which is larger than an outer diameter of said annular section, and said annular section is supported in said opening through said plurality of resilient sections.

7. The vibration gyro sensor according to claim 1, wherein the contour of each of said resilient sections is constructed by a ring section having an approximately elliptical planar configuration with its minor axis directed in a radial direction with respect to the longitudinal axis of said annular section.

8. The vibration gyro sensor according to claim 1, wherein the contour of each of said resilient sections is constructed by a ring section having an approximately elliptical planar configuration with its major axis directed in a radial direction with respect to the longitudinal axis of said annular section.

9. The vibration gyro sensor according to claim 1, wherein:

said support member comprises an outer support member disposed outside said annular section, for resiliently supporting said annular section, and an inner support member disposed inside said annular section, for resiliently supporting said annular section;

said resilient sections comprise outer resilient sections provided between said outer support member and said annular section, and inner resilient sections provided between said inner support member and said annular section, at least one of said outer resilient sections has said plate-shaped portion and at least one of said inner resilient sections has said plate-shaped portion; and

said piezoelectric/electrostrictive elements are formed on said plate-shaped portions of said at least one outer resilient section and said at least one inner resilient section.

10. The vibration gyro sensor according to claim 9, wherein:

said inner support member has an approximately circular planar configuration with an outer diameter which is smaller than an inner diameter of said annular section;

said outer support member has an opening having an approximately circular planar configuration with an inner diameter which is larger than an outer diameter of said annular section; and

said annular section is supported in said opening through said plurality of resilient sections.

11. The vibration gyro sensor according to the claim 9, wherein the contour of said inner resilient sections and said outer resilient sections is constructed by a ring section having an approximately elliptical planar configuration with its minor axis directed in a radial direction with respect to the longitudinal axis of said annular section.

12. The vibration gyro sensor according to claim 9, wherein the contour of said inner resilient sections and said outer resilient sections is constructed by a ring section having an approximately elliptical planar configuration with its major axis directed in a radial direction with respect to the longitudinal axis of said annular section.

13. The vibration gyro sensor according to claim 9, wherein said plurality of inner and outer resilient sections are arranged at positions separated from each other by equal spacing distances and are mutually point-symmetrical respectively.

14. The vibration gyro sensor according to claim 9, wherein said first piezoelectric/electrostrictive element is formed on at least one resilient section of one of said inner resilient sections and said outer resilient sections and is a driving element for vibrating said resilient sections and said second piezoelectric/electrostrictive element is formed on at least one resilient section of the other one of said inner and outer resilient sections and is a detecting element for detecting a strain caused by vibration generated in a direction of 45°

with respect to a direction of vibration of said resilient sections, upon rotation about the longitudinal axis of said annular section.