Rotation-speed sensor device

• US 20030093188A1
• Filed: 10/18/2002
• Published: 05/15/2003
• Est. Priority Date: 10/18/2001
• Status: Active Grant

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Sakatani, Ikunori, Morita, Kouichi, Endo, Shigeru, Nakamura, Yuji, Miyazaki, Hiroya, Sakamoto, Junshi
• Granted Patent: US 6,830,379 B2
• Time in Patent Office: Days
• US Class Current: 701/1
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/042 cooperating with wheel hub mounted speed sensors
• CPC Class Codes: F16C 19/185 with two raceways provided integrally on a part other than a race ring, e.g. a shaft or housing
• 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 19/386 in O-arrangement
• CPC Class Codes: F16C 2326/02 Wheel hubs or castors
• 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 1/026 for speed measuring devices, e.g. pulse generator
• CPC Class Codes: G01P 3/443 mounted in bearings bearings F16C
• CPC Class Codes: G01P 3/446 mounted between two axially spaced rows of rolling elements

Abstract

A rotation-speed sensor device is provided to comprise an encoder supported by a rotating race of a rolling bearing unit for vehicle wheel support to be concentric with the rotating race and having a detected portion the characteristics of which are alternately changed in a circumferential direction, a rotation detection sensor supported by a non-rotating member on the vehicle chassis side and having a detecting portion facing the detected portion to produce a detection signal, a wireless transmission device for sending the detection signal from the rotation detection sensor to a controller provided on the vehicle chassis side, and a self-diagnosis circuit to judge whether there is an error or not in the rotation detection sensor.

Claims

1. A rotation-speed sensor device comprising:

an encoder supported by a rotating race to be concentric with the rotating race and having a detected portion the characteristics of which are alternately changed in a circumferential direction, the rotating race composing a rolling bearing unit for wheel support to rotate together with a wheel when moving,

a first rotation detection sensor supported by a non-rotating member and having a detecting portion facing the detected portion to produce a detection signal,

a wireless transmission device for sending the detection signal from the first rotation detection sensor to a controller provided on the vehicle chassis side, and

a self-diagnosis circuit to judge whether there is a problem or not in detecting rotation-speed.

2. The rotation-speed sensor device of claim 1, wherein the first rotation detection sensor has a coil to generate electric power therethrough by way of magnetic flux change caused as the encoder rotates, and wherein the self-diagnosis circuit comprising a battery provided in the non-rotating member to be charged with the electric power generated by the first rotation detection sensor, and a judgement circuit supplied with power from the battery to judge whether there is a problem in detecting rotation-speed, and wherein the self-diagnosis circuit has a function to send a signal indicating a problem when the problem in detecting the rotation-speed is detected by the judgement circuit.

3. The rotation-speed sensor device of claim 1, wherein the first rotation detection sensor has a coil to generate electric power therethrough by way of magnetic flux change caused as the encoder rotates, and wherein a calculation device is provided to calculate a first vehicle speed based on the signal from the first rotation detection sensor and to calculate a second vehicle speed based on a second rotation detection sensor provided on a transmission portion, and wherein the self-diagnosis circuit judges that there is a problem in detecting rotation-speed when there is a difference between the first vehicle speed and the second vehicle speed beyond a predetermined value.

4. The rotation-speed sensor device of one of claims 2 and 3, wherein when the judgement circuit has judged that there is an error in the signal sent from the first rotation detection sensor, an anti-lock brake system is controlled based on the signal sent from the second rotation detection sensor, wherein the error in the signal sent from the first rotation detection sensor is removed within a predetermined period of time, the control on the anti-lock brake system is restarted based on the signal sent from the first rotation detection sensor, and wherein the error in the signal sent from the first rotation detection sensor is not removed in the predetermined period of time, the anti-lock brake system is stopped in function.

8. A transmitter-receiver device for wheel speed signal for use in the rotation-speed sensor device of claim 1, wherein the transmission device has a transmitter to transmit a vehicle speed signal and a receiver to receive the vehicle speed signal, and wherein the transmitter is mounted to the stationary side of the rolling bearing unit and exposed in a first transmission space enclosed by a brake rotor, a backing plate and the rolling bearing unit which are made from metal members, and wherein the receiver is mounted to one of the backing plate and a knuckle which are made from metal members, and exposed in the first transmission space.

9. A transmitter-receiver device for wheel speed signal for use in the rotation-speed sensor device of claim 1, wherein the transmission device has a transmitter to transmit a vehicle speed signal and a receiver to receive the vehicle speed signal, and wherein the transmitter is mounted to the stationary side of the rolling bearing unit and exposed in a second transmission space enclosed by a knuckle and the rolling bearing unit which are made from metal members, and wherein the receiver is mounted to the knuckle which is made from a metal member, and exposed in the second transmission space.

10. A transmitter-receiver device for wheel speed signal for use in the rotation-speed sensor device of claim 1, wherein the transmission device has a transmitter to transmit a vehicle speed signal and a receiver to receive the vehicle speed signal, and wherein at least one of a braking rotor, backing plate, knuckle and vehicle floor is made from a non-metal member, and wherein the transmitter is mounted to the stationary side of the rolling bearing unit and exposed in a third transmission space enclosed by the non-metal member and the rolling bearing unit, and wherein the receiver is located outside the third transmission space within an area in which transmission is possible through the non-metal member.

11. A transmitter-receiver device for wheel speed signal for use in the rotation-speed sensor device of claim 1, wherein the wheel has a tire mounted thereto, and wherein the transmission device has a transmitter to transmit a vehicle speed signal and a receiver to receive the vehicle speed signal, and wherein the receiver receives both of the wheel speed signal and a signal indicating air pressure in the tire.

5. A rolling bearing unit with a rotation-speed sensor device for use in wheel support:

the rolling bearing unit comprising a rotating race which rotates together with a wheel when moving,

the rotation-speed sensor device comprising an encoder supported by a rotating race to be concentric with the rotating race and having a detected portion the characteristics of which are alternately changed in a circumferential direction,

a rotation detection sensor supported by a non-rotating member and having a detecting portion facing the detected portion to produce a detection signal,

a wireless transmission device for sending the detection signal from the rotation detection sensor to a controller provided on the vehicle chassis side, and

a self-diagnosis circuit to judge whether there is a problem or not in detecting rotation-speed, and wherein the wireless transmission device has a transmission circuit which is kept with the rotation detection sensor in a single holder to form a sensor unit.

6. The rotation-speed sensor device of claim 5, wherein the encoder and the rotation detection sensor are located in a closed space from the outside space.

7. The rotation-speed sensor device of claim 5, wherein the transmission device has an antenna located outside the enveloping line of the metal parts of the rolling bearing unit.

12. A double-row rolling bearing with a sensor unit comprising an outer race having an inner peripheral surface formed with outer-ring raceways, an inner race having an outer peripheral surface formed with inner-ring raceways, rolling elements provided between the outer-ring raceways and the inner-ring raceways so as to roll therebetween, an encoder ring fixed to one of the outer race and inner race directly or through another member, and a sensor unit comprising sensors for detecting different states and a casing made from a material having good thermal conductivity to contain the sensors therein, the sensor unit being supported by the other of the outer race and inner race directly or through another member to face the encoder ring in a space isolated from the outside.

13. A double-row rolling bearing with a sensor unit comprising an outer race having an inner peripheral surface formed with outer-ring raceways, an inner race having an outer peripheral surface formed with inner-ring raceways, rolling elements provided between the outer-ring raceways and the inner-ring raceways so as to roll therebetween, an encoder ring fixed directly to the inner race, and a sensor unit comprising sensors for detecting different states and supported directly by the outer race to face the encoder ring.