Two-axis yaw rate sensor

• US 6,539,804 B1
• Filed: 06/09/2000
• Issued: 04/01/2003
• Est. Priority Date: 06/22/1998
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Original Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Inventors: Iwata, Hitoshi
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US09/581,360
• Time in Patent Office: 1,026 Days
• Field of Search: 735/041.3, 735/041.2, 735/041.4, 310/321, 310/329
• US Class Current: 73/504.13
• CPC Class Codes: G01C 19/5677 of essentially two-dimensional vibrators, e.g. ring-shaped vibrators

Abstract

A two-axis yaw rate sensor (1) includes a vibration ring (15) and a ring support plate for supporting the vibration ring (15). The vibration ring (15) includes first to fourth vibrating drive surfaces (16a-16d) arranged in turn in a circumferential direction and narrow portions (17) located between the adjacent drive surfaces (16a-16d). The first and the third drive surfaces (16a, 16c) are opposed to one another on the axis Y passing through the center of the vibration ring (15). The second and the fourth drive surfaces (16b, 16d) are opposed to one another on the axis X passing through the center of the vibration ring (15). The axis Y is substantially perpendicular to the axis X. A PZT film (15) is formed on the drive surfaces (16a-16d) and vibrates the drive surfaces (16a-16d) in a radial direction of the vibrating ring (15). A weight (21) is coupled to a coupling portion (22) of each drive surface (16a-16d) and vibrates in a direction substantially perpendicular to the vibrating direction of the vibrating surfaces (16a-16d). Detection electrode films (24a-24d) are formed on the coupling portions (22) and detect the deformation of the corresponding coupling portions (22).

Claims

1. A two-axis yaw rate sensor comprising:

a ring-shaped member;

wherein the ring-shaped member includes first to fourth vibrating drive surfaces located in order in a circumferential direction and support parts located between the adjacent drive surfaces, wherein the first and the third drive surfaces are opposed to one another on a first axis passing through the center oft he ring-shaped member, the second and the fourth drive surfaces, are opposed to one another on a second axis passing through the center of the ring-shaped member, the second axis being substantially perpendicular to the first axis;

a support member for supporting the ring-shaped member at each support part;

a piezoelectric member, which is located on each drive surface and vibrates the corresponding drive surface in a radial direction of the ring-shaped member;

a coupling portion extending from each drive surface;

a weight, which is coupled to each coupling portion and moves in a direction substantially perpendicular to the vibrating direction of the drive surfaces wherein each weight is located in a middle portion of the corresponding drive surface and extends radially outward relative to the center of the ring-shaped member; and

a deformation detection member formed on each coupling portion for detecting the deformation of the corresponding coupling portion.

2. The two-axis yaw rate sensor according to claim 1, wherein the ring-shaped member and the weight are formed of a common metal plate.

3. The two-axis yaw rate sensor according to claim 2, wherein the support member is integrally coupled to the support part and is formed of the same metal plate as the ring-shaped member.

4. The two-axis yaw rate sensor according to claim 3, wherein the support member is substantially cross-shaped.

5. The two-axis yaw rate sensor according to claim 1, wherein the drive surfaces are formed on a peripheral surface of the ring-shaped member.

6. The two-axis yaw rate sensor according to claim 1, wherein the piezoelectric member includes a PZT film.