Apparatus for detecting rotational state of wheel

• US 6,747,553 B2
• Filed: 09/28/2001
• Issued: 06/08/2004
• Est. Priority Date: 09/29/2000
• Status: Expired due to Term

• Current Assignee: Advics Company Limited (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ota, Toshinobu, Ishida, Yasuhito, Yamada, Noritaka
• Primary Examiner(s): GOINS, DAVETTA WOODS
• Application Number:
  US09/964,434
• Publication Number:
  US 20020040268A1
• Time in Patent Office: 984 Days
• Field of Search: 340/441, 340/444, 340/453, 340/442, 340/448, 340/438, 340/686.3, 340/671, 340/672, 180/197, 701/71, 701/74, 701/79, 324/207.13, 324/165, 324/166, 324/202, 324/207.25, 188/197, 188/282, 303/113.5, 303/122, 702/145, 702/148
• US Class Current: 340/441
• CPC Class Codes: B60T 8/171 Detecting parameters used in the regulation; Measuring values used in the regulation
• CPC Class Codes: G01P 13/045 with speed indication
• CPC Class Codes: G01P 21/02 of speedometers

Abstract

Provided is rotational-state-of-wheel detecting apparatus that can avoid output of an incorrect rotational direction during a halt of a wheel. In ECU 10, a signal input section 10a accurately detects wheel speeds and rotational directions of respective wheels 12, 14, 16, 18, and, based on the results, respective computers 10b, 10c, 10d execute ABS control, TC control, and VSC control. On this occasion, switching of the rotational direction is restricted with a computation result of wheel speed of zero, and it is thus feasible to prevent occurrence of a malfunction or state hunting being repetitive switching of signs, due to an external magnetic field during halts of the wheels 12, 14, 16, 18. This further optimizes the state control of a vehicle.

Claims

1. An apparatus for detecting a rotational state of a wheel, comprising a rotating member to rotate together with the wheel, a detected portion provided at said rotating member, detecting means for detecting passage of said detected portion and outputting a detection signal, and rotational direction detecting means for detecting a rotational direction of the wheel, based on the output from said detecting means,

said apparatus further comprising halt detecting means for detecting whether the wheel is in a halt or not, and restricting means for restricting a change of the rotational direction detected by the rotational direction detecting means, when said halt detecting means detects that the wheel is in a halt.

2. The apparatus according to claim 1, wherein said detected portion is a magnetic material and said detecting means is a magnetic sensor.

3. The apparatus according to claim 2, wherein said magnetic sensor is a pair of Hall elements or a pair of MR elements.

4. The apparatus according to claim 1, wherein said halt detecting means is means for detecting whether the wheel is in a halt or not, based on the output from said detecting means.

5. The apparatus according to claim 4, wherein said halt detecting means determines that the wheel is in a halt, when a wheel speed detected based on the output from said detecting means is not more than a predetermined value.

6. The apparatus according to claim 1, wherein information about the rotational direction outputted from said rotational direction detecting means is utilized in an antilock brake system.

7. The apparatus according to claim 1, wherein information about the rotational direction outputted from said rotational direction detecting means is utilized in a traction control system for preventing slipping of a driving wheel.

8. The apparatus according to claim 1, wherein information about the rotational direction outputted from said rotational direction detecting means is utilized in a vehicle stability control system for controlling a posture of a vehicle during cornering thereof.