Rotation angle detector

• US 7,154,263 B2
• Filed: 11/29/2005
• Issued: 12/26/2006
• Est. Priority Date: 01/12/2005
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Hatano, Yoichi
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): Schindler, David M.
• Application Number:
  US11/288,286
• Publication Number:
  US 20060152214A1
• Time in Patent Office: 392 Days
• Field of Search: 324/207.25
• US Class Current: 324/207.25
• CPC Class Codes: G01D 2205/28 The target being driven in rotation by additional gears
• CPC Class Codes: G01D 3/08 with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: G01D 5/24461 by redundancy or plausibility

Abstract

Disclosed here is a rotation angle detector capable of detecting unusual value as a rotation angle so as not to output incorrect data. According to the rotation angle detector of the present invention, the first detector, the second detector, and the auxiliary detector rotate at a different speed. Receiving each detecting signal from i) the first and second rotation-detecting sections; ii) the second rotation-detecting section and the auxiliary rotation-detecting section; and iii) the first rotation-detecting section and the auxiliary rotation-detecting section, the controller calculates at least two tentative values for determining the rotation angle of the rotator. When the calculation values are within a predetermined range, the controller determines the detecting signal from the first and second rotation-detecting sections to be the rotation angle of the rotator.

Claims

1. A rotation angle detector, comprising:

a rotator that rotates in engagement with an object;

a first detector that rotates in engagement with the rotator;

a second detector that rotates in engagement with the first detector;

a first rotation-detecting section for detecting a rotation of the first detector;

a second rotation-detecting section for detecting a rotation of the second detector;

an auxiliary detector that rotates in engagement with the rotator;

an auxiliary rotation-detecting section for detecting a rotation of the auxiliary detector; and

a controller for detecting the rotation angle of the rotator from detecting signals fed from the first rotation-detecting section and the second rotation-detecting section, wherein, the first detector, the second detector, and the auxiliary detector each rotate at a different speed, the controller receives each detecting signal from i) the first rotation-detecting section and the second rotation-detecting section;

ii) the second rotation-detecting section and the auxiliary rotation-detecting section; and

iii) the first rotation-detecting section and the auxiliary rotation-detecting section to calculate at least two tentative values for the rotation angle, the controller employs the detecting signal received from the first rotation-detecting section and the second rotation-detecting section for detecting the rotation angle of the rotator when the calculated values are within a predetermined range.

2. The rotation angle detector of claim 1, wherein the controller outputs a warning signal when any one of the tentative values for the rotation angle does not fall within the predetermined range.