Detection of revolutions of a tire and wheel assembly by means of the Earth's magnetic field

• US 20060152212A1
• Filed: 12/08/2005
• Published: 07/13/2006
• Est. Priority Date: 06/16/2003
• Status: Active Grant

• Current Assignee: Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA)
• Original Assignee: Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA)
• Inventors: Beranger, Marc, Jeandey, Christian
• Granted Patent: US 7,360,411 B2
• Time in Patent Office: Days
• US Class Current: 324/165
• CPC Class Codes: B60C 23/0488 Movement sensor, e.g. for sensing angular speed, acceleration or centripetal force
• CPC Class Codes: B60C 23/0489 for detecting the actual angular position of the monitoring device while the wheel is turning

Abstract

The present invention relates to an autonomous device which is intended to be carried by a tire and wheel assembly in order to detect revolutions of said assembly, comprising at least one sensor which produces signals and an interpreter device which is connected to the sensor in order to interpret the signals produced by the sensor. The sensor is a passive sensor, the produced signals of which are proportional to the temporal variations of a magnetic flux though this sensor, and is intended to be integral in rotation with the tire such that the revolutions of said assembly correspond to the revolutions of said sensor. The invention likewise relates to an assembly provided with an autonomous device which permits detection of revolutions of the assembly, and a method for detecting revolutions of the assembly.

Claims

1. Autonomous device which is intended to be carried by a tire and wheel assembly in order to detect revolutions of said assembly, comprising at least one sensor producing signals, which is intended to be integral in rotation with said assembly such that revolutions of said assembly correspond to revolutions of said sensor, characterized in that the sensor is a passive sensor, the produced signals of which are proportional to the temporal variations of a magnetic flux.

2. Device according to claim 1, in which the sensor is a loop of conductive wire.

3. Device according to claim 2, in which the sensor is a winding with an equivalent surface greater than 0.15 m².

4. Device according to claim 1, sensitive to temporal variations of the magnetic flux caused by the rotation of said device in the Earth'"'"'s magnetic field.

5. Device according to claim 1, in which the sensor is intended to be placed on said assembly such that its direction of sensitivity is orthogonal to the axis of rotation of said assembly.

6. Device according to claim 5, in which the sensor is intended to be placed on said assembly such that its direction of sensitivity is orientated radially with respect to said assembly.

7. Device according to claim 6, in which the sensor is intended to be placed in proximity to the bead wires of the tire.

8. Device according to claim 6, in which the sensor is intended to be placed at the level of the crown of said tire.

9. Device according to claim 1, comprising an interpreter which produces an impulse each time it has detected at least one cycle of signals produced by the passive sensor.

10. Device according to claim 9, in which the interpreter comprises a comparator.

11. Device according to claim 10, in which the interpreter comprises filtration means for the signals produced by the sensor.

12. Device according to claim 11, in which the interpreter comprises amplification means for the signals.

13. Device according to claim 12, comprising a counting means which is connected to the interpreter.

14. Device according to claim 13, in which the counting means comprises a counter which, each time it has received a pre-determined number of impulses on the part of the interpreter, transmits an impulse to a micro-controller comprising storage means for the number of impulses received from the counter.

15. Device according to claim 14 comprising a device for transmission, towards the exterior, of data which are characteristic of the number of impulses stored by the micro-controller).

16. Device according to claim 1, comprising a plurality of passive captors, which are intended to be carried by the circumference of said assembly, and an interpreter which is capable of adding the signals produced by these sensors.

17. Device according to claim 16, in which the interpreter is capable of putting the produced signals back in phase before adding them.

18. Device according to any of the claims 1, such that the tire and wheel assembly with which it is equipped comprises a steel wheel rim.

19. Wheel provided with a device according to claim 1.

20. Wheel according to claim 19, such as is formed in steel.

21. Tire provided with a device according to claim 1.

22. Method for detecting the revolutions of a tire and wheel assembly, comprising placing on this assembly at least two sensors, which produce signals proportional to the temporal variations of a magnetic flux, putting the signals back in phase, adding the signals and detecting the periods of the result of this addition.