Rotation detecting device and anti-skid braking system using the same

• US 7,741,838 B2
• Filed: 01/17/2008
• Issued: 06/22/2010
• Est. Priority Date: 03/08/2002
• Status: Expired due to Fees

• Current Assignee: NTN Corporation
• Original Assignee: NTN Corporation
• Inventors: Iwamoto, Kenichi, Okada, Koichi, Ohba, Hiroaki, Takahashi, Toru
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): Sriraman; Nikhil
• Application Number:
  US12/015,950
• Publication Number:
  US 20080133100A1
• Time in Patent Office: 887 Days
• Field of Search: 73/14.1, 735/143.9, 384/448, 377/89, 340/870.31, 324/207.2, 324/207.21, 324/207.25
• US Class Current: 324/160
• CPC Class Codes: B60T 8/171 Detecting parameters used in the regulation; Measuring values used in the regulation
• CPC Class Codes: B60T 8/329 Systems characterised by their speed sensor arrangements
• CPC Class Codes: F16C 19/186 with three raceways provided integrally on parts other than race rings, e.g. third generation hubs
• CPC Class Codes: F16C 2326/02 Wheel hubs or castors in general B60B
• CPC Class Codes: F16C 33/7886 mounted outside the gap between the inner and outer races, e.g. sealing rings mounted to an end face or outer surface of a race
• CPC Class Codes: F16C 41/004 Electro-dynamic machines, e.g. motors, generators, actuators
• CPC Class Codes: F16C 41/007 Encoders, e.g. parts with a plurality of alternating magnetic poles
• CPC Class Codes: F16C 41/008 Identification means, e.g. markings, RFID-tags; Data transfer means
• CPC Class Codes: G01P 3/443 mounted in bearings bearings F16C

Abstract

A rotation detecting device that includes an electric power generator having a stator and a rotor, said rotor having a plurality of alternating opposite magnetic poles in a circumferential direction of the rotor, at least a first magnetic sensor mounted on either the stator or a support member for supporting the stator and operable to detect the alternating opposite magnetic poles in the rotor; and an electric power supply circuit for utilizing an electric power generated by the electric power generator as an electric power source for the at least first magnetic sensor.

Claims

1. A rotation detecting device comprising:

a rotation detector having a capability of detecting the rotational speed and including an electric power generator having a rotor and a stator;

a transmitting device to wirelessly transmit a rotation signal indicative of the rotational speed detected by the rotation detector;

an electric power supply circuit to utilize an electric power generated by the electric power generator to electrically power the transmitting device;

a wireless switching device to selectively switch on or off supply of the electric power from the electric power supply circuit, said wireless switching device including a tuning circuit to detect a radio wave of a particular frequency and a semiconductor switching element interposed in the electric power supply circuit and capable of being selectively turned on or off in response to a detection signal of the radio wave detected by the tuning circuit, said wireless switching device in its entirety being electrically powered by an electric power of the detection signal of the radio wave detected by the tuning circuit.

2. The rotation detecting device as claimed in claim 1, wherein the electric power supply circuit includes an electric component part selected from the group consisting of an electric double layer capacitor, a secondary cell and a primary cell to compensate a reduction of the electric power generated by the electric power generator at a low speed rotation of the rotor.

3. The rotation detecting device as claimed in claim 1, wherein the rotation detector includes a sensor utilizing the electric power generator as an electric power source therefor, the rotational speed being detected by the sensor.

4. The rotation detecting device as claimed in claim 1, wherein the rotor of the electric power generator is mounted on a rotatable member of a wheel support bearing assembly,

the stator of the electric cower generator is mounted on a non-rotatable member of the wheel support bearing assembly, and

the signal, transmitted by the wireless transmitting device and indicative of the rotational speed, is used for controlling an automobile anti-skid braking system.