Antifriction bearing including microsensor for determining parameters, in particular wheel bearing for motor vehicles

• US 6,002,248 A
• Filed: 03/31/1997
• Issued: 12/14/1999
• Est. Priority Date: 03/30/1996
• Status: Expired due to Fees

• Current Assignee: FAG Kugelfischer Georg Schã¤Fer AG (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: FAG Automobiltechnik AG (INA-Holding Schaeffler GmbH & Co. KG)
• Inventors: Binder, Josef
• Primary Examiner(s): Snow, Walter E.
• Application Number:
  US08/831,467
• Time in Patent Office: 988 Days
• Field of Search: 324/160, 324/162, 384/448, 340/670, 340/671, 180/174, 180/282, 73/488, 73/514.01, 200/61.45 R, 280/734, 280/735
• US Class Current: 324/160
• CPC Class Codes: B60G 2204/115 Wheel hub bearing 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 41/00 Other accessories, e.g. devices integrated in the bearing not relating to the bearing function as such
• CPC Class Codes: F16C 41/008 Identification means, e.g. markings, RFID-tags; Data transfer means
• CPC Class Codes: G01P 15/0888 for indicating angular acceleration
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/135 by making use of contacts which are actuated by a movable inertial mass
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 3/44 for measuring angular speed G01P3/56 takes precedence
• CPC Class Codes: G01P 3/443 mounted in bearings bearings F16C

Abstract

In order to achieve direct digital data recording and reliable and space saving and cost saving recording of the status of an antifriction bearing, in particular a wheel bearing for motor vehicles, sensors record the rotational speed and acceleration of the wheels and driving and/or braking forces. The sensors are microsensors in the form of microswitch arrays, at least one of which is attached to the rotating ring of the bearing, and the generated signals are compared with stored basic patterns or with the signals of an identical or similar microsensor arranged on the stationary ring of the bearing and/or are evaluated.

Claims

1. An antifriction bearing including an outer ring and an inner ring wherein the rings are relatively rotatable and bearing rolling elements between the inner and outer rings;

a microsensor for recording rotational speed or acceleration and various driving and braking forces between the rings;

the microsensor being in the form of a microswitch array attached to the rotating one of the rings, and the microswitch array being adapted to generate a signal that is to be compared with another signal to sense at least one of the factors comprising the speed, acceleration, driving forces and braking forces on the one ring with reference to the other ring.

2. The antifriction bearing with sensors of claim 1, further comprising comparison means with which the signal from the microswitch array on the rotating part of the bearing is compared for sensing at least one of the factors.

3. The antifriction bearing with sensors of claim 2, wherein the comparison means comprises means of storing a basic pattern signal.

4. The antifriction bearing of claim 1, further comprising a second microsensor attached to the stationary one of the bearing rings and generating a comparison signal and means for comparing the signals of the first sensor with the signals of the second sensor for determining at least one of the factors.

5. The antifriction bearing of claim 1, wherein the microsensor comprises a microsize array of moveable bending bars arranged in an array of bending bars in a system, the bars being oriented and adapted to move laterally under the influence of force, and

respective stops positioned for being contacted by each of the bending bars upon the application of certain forces to the bars, the stops being connected for generating a signal when contacted by the respective bar for producing the signal of the microsensor.

6. The bearing of claim 4, wherein the laterally movable bending bars are each respectively differently mounted, shaped and oriented as to provide responses at different levels of force applied to the bearing.

7. The bearing of claim 6, wherein the bending bars each have respective characteristics selected from the group consisting of different properties of the bar for bending to different extents, different operating points where the extent of bending causes the sensor to sense, varying differences between the stops for the bending bars for causing sensing at different force levels including varying dimensions of the bending bars including the length of bars.

8. The bearing of claim 1, wherein the microsensor is arranged on a chip which is fixed with respect to the respective ring.

9. The antifriction bearing of claim 1, wherein the microswitch array has variable characteristics that are selected from the group consisting of different switching times, different sensitivities, different resonant frequencies and different damping systems.

10. The antifriction bearing of claim 1, wherein energy supplied to the microswitch array at the moving ring of the bearing is by means of telemetry.

11. The antifriction bearing of claim 1, wherein energy supplied to the microswitch array on the moving ring of the bearing is by means of inductive coupling.

12. The antifriction bearing of claim 11, wherein the inductive coupling comprises coils in the moving ring which comprise electroplated and microstructured planar coils.

13. The antifriction bearing of claim 1, wherein the signal transmission from the rotating microswitch array is by means of telemetry.

14. The antifriction bearing of claim 1, wherein the signal transmission from the rotating microswitch array is by means of inductive coupling.

15. The antifriction bearing of claim 3, wherein energy supplied to and signal transmission from the comparison means at the stationary ring of the bearing is accomplished by telemetry.

16. The antifriction bearing of claim 3, wherein energy supplied to and signal transmission from the stationary ring of the bearing is accomplished by cable transmission thereto.

17. The antifriction bearing of claim 5, wherein the microsensor array comprises up to about 50 individual bars.

18. The antifriction bearing of claim 1, further comprising a chip supporting two of the microsensor arrays on the moving one of the rings, one of the arrays being arranged parallel to and the other array being arranged perpendicular to the radially acting centrifugal force on the rotating microsensor.

19. The antifriction bearing of claim 8, wherein the microsensor comprises a microsize array of moveable bending bars arranged in an array of bending bars in a system arranged on the chip, the bars being oriented and adapted to move laterally under the influence of force, and

respective stops positioned for being contacted by each of the bending bars upon the application of certain forces to the bars, the stops being connected for generating a signal when contacted by the respective bar for producing the signal of the microsensor.

20. A method of sensing for recording the rotational speed or acceleration of wheels and driving and braking forces of a vehicle, wherein the vehicle has a plurality of wheels, and has a respective antifriction bearing at each of the wheels, with one ring of the bearing being connected with the wheel for rotating therewith and the other ring of the bearing being connected with the vehicle;

a respective sensor for recording the rotational speed, acceleration of the wheel and driving and braking forces on the wheel, wherein each of the sensors is designed as a microsensor in the form of a microswitch array attached to the moving ring of the bearing and generating a signal upon rotation of the wheel;

the method ring comprising

comparing the generated signal with another signal for determining the speed, acceleration, driving and braking forces on the wheel, and evaluating the signals of all of the sensors on all of the wheels for determining the factors of speed, acceleration, driving and braking forces on the vehicle.

21. The method of claim 20, wherein the microsensor comprises a microsize array of moveable bending bars arranged in an array of bending bars in a system, the bars being oriented and adapted to move laterally under the influence of force, and

respective stops positioned for being contacted by each of the bending bars upon the application of certain forces to the bars, the stops being connected for generating a signal when contacted by the respective bar for producing the signal of the microsensor;

the method comprising modifying the switching patterns of the bending bars as a digital word which is evaluated.

22. The method of claim 20, comprising comparing the rotational speed of the wheels, the lateral forces on the rotating and stationary part of each bearing, the tangential force or angular acceleration on the rotating system, the lateral forces and indirectly, by comparing the lateral acceleration with the angular acceleration, the slip being recorded for evaluating the travelling status.