ROTATION ANGLE DETECTOR

• US 20080238416A1
• Filed: 04/01/2008
• Published: 10/02/2008
• Est. Priority Date: 04/02/2007
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Okada, Mayuko, Noda, Hiromitsu, Shiraga, Shozoh, Ohta, Tamotsu
• Granted Patent: US 7,535,219 B2
• Time in Patent Office: Days
• US Class Current: 324/207.25
• CPC Class Codes: B62D 15/0215 by measuring on the steering column
• CPC Class Codes: B62D 15/0245 Means or methods for determination of the central position of the steering system, e.g. straight ahead position
• CPC Class Codes: G01B 7/30 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01D 2205/26 Details of encoders or position sensors specially adapted to detect rotation beyond a full turn of 360°, e.g. multi-rotation
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

A rotation angle detector includes a rotator, first and second detecting bodies, an auxiliary detecting body, first and second detectors, an auxiliary detector, and a controller. The first detecting body rotates in association with the rotator, and the first detector detects rotation of the first detecting body. The second detecting body rotates in association with the first detecting body at a different speed therefrom, and the second detector detects rotation of the second detecting body. The auxiliary detecting body is engaged with the rotator at a position symmetrical to the first detecting body with respect to a rotation axis of the rotator. The auxiliary detector detects rotation of the auxiliary detecting body. The controller detects a rotation angle of the rotator based on detection signals from the first, second, and auxiliary detectors.

Claims

1. A rotation angle detector comprising:

a rotator;

a first detecting body configured to rotate in association with the rotator;

a first detector configured to detect rotation of the first detecting body;

a second detecting body configured to rotate at a different speed from the first detecting body in association with the first detecting body;

a second detector configured to detect rotation of the second detecting body;

an auxiliary detecting body engaged with the rotator at a position symmetrical to the first detecting body with respect to a rotation axis of the rotator;

an auxiliary detector configured to detect rotation of the auxiliary detecting body; and

a controller configured to detect a rotation angle of the rotator based on detection signals from the first detector, from the second detector, and from the auxiliary detector.

2. The rotation angle detector according to claim 1, wherein

when only one of the first detector and the auxiliary detector outputs the detection signal, the controller detects the rotation angle of the rotator based on the detection signal output from the one of the first detector and the auxiliary detector.

3. The rotation angle detector according to claim 1, wherein

the second detecting body and the auxiliary detecting body are rotated at a same speed.

4. The rotation angle detector according to claim 1, wherein

the controller is configured to compare the detection signals from the auxiliary detector and from the first detector.

5. The rotation angle detector according to claim 4, wherein

the controller is configured to detect the rotation angle by using larger one of the detection signals from the auxiliary detector and from the first detector, as the rotation angle.

6. The rotation angle detector according to claim 4, wherein

when there is a difference not less than a predetermined value between the detection signals from the auxiliary detector and from the first detector, the controller determines that an abnormality has occurred in at least one of the first detecting body, the auxiliary detecting body, the first detector, and the auxiliary detector.

7. The rotation angle detector according to claim 1, wherein

the rotation axis of the rotator, and rotation axes of the first detecting body, the second detecting body, and the auxiliary detecting body are parallel to each other.

8. The rotation angle detector according to claim 1, wherein

at least one of rotation axes of the first detecting body, the second detecting body, and the auxiliary detecting body forms an angle of other than 0 degrees with the rotation axis of the rotator.

9. The rotation angle detector according to claim 8, wherein

at least one of the rotation axes of the first detecting body, the second detecting body, and the auxiliary detecting body is perpendicular to the rotation axis of the rotator.