Rotation detecting device for detecting direction of rotation

• US 6,242,904 B1
• Filed: 08/24/1998
• Issued: 06/05/2001
• Est. Priority Date: 08/25/1997
• Status: Expired due to Term

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Shirai, Katsuyoshi, Suzumura, Nobuyasu, Iwase, Eiichiro
• Primary Examiner(s): PATIDAR, JAY M
• Application Number:
  US09/138,577
• Time in Patent Office: 1,016 Days
• Field of Search: 324/165, 324/207--20, 324/166, 324/168, 324/173, 324/174, 324/175, 324/233, 338/32.R, 338/32.H
• US Class Current: 324/165
• CPC Class Codes: G01D 2205/85 Determining the direction of movement of an encoder, e.g. of an incremental encoder
• CPC Class Codes: G01D 5/2451 Incremental encoders G01D5/2454 takes precedence
• CPC Class Codes: G01P 3/488 delivered by variable reluctance detectors

Abstract

A rotation detector (100) includes a first transmitting element (1) and a second transmitting element (3) each disposed opposite a gear rotor (5) attached to a rotating body as a detected member. A signal processing device (13) is connected to the first transmitting element and the second transmitting element for generating pulse signals based on rotation signals generated by the first transmitting element and the second transmitting element. The rotation detector is characterized in that the signal processing device generates the pulse signals with different pulse widths to distinguish between the case where the first transmitting element generates the rotation signal prior to the first transmitting element and the case where the second transmitting element generates the rotation signal prior to the first transmitting element.

Claims

1. A rotation detector, comprising:

a first transmitting element and a second transmitting element each disposed opposite a gear rotor attached to a rotating body as a detected member; and

a signal processing device connected to said first transmitting element and said second transmitting element for generating pulse signals based on rotation signals generated by said first transmitting element and said second transmitting element and transmitted to the signal processing device, wherein said signal processing device generates pulse signals with a first pulse width when said first transmitting element generates the rotation signal prior to said second transmitting element and generates pulse signals with a second pulse width greater than the first pulse width when the second transmitting element generates the rotation signal prior to said first transmitting element, whereby the signal processing device determines the rotational direction of the gear rotor by the order of the rotation signals generated by the first and second transmitting element and generates a pulse with different width depending on the rotational direction.