Method for monitoring tyre deformations and monitoring system therefor

• US 7,412,879 B2
• Filed: 09/19/2003
• Issued: 08/19/2008
• Est. Priority Date: 09/19/2003
• Status: Expired due to Fees

• Current Assignee: Pirelli Pneumatici S.P.A. (Pirelli & C SPA)
• Original Assignee: Pirelli Pneumatici S.P.A. (Pirelli & C SPA)
• Inventors: Caretta, Renato, Albizzati, Enrico, Cipriani, Chiara, Serra, Stefano, Carrus, Antonio
• Primary Examiner(s): Allen; Andre J.
• Assistant Examiner(s): Jenkins; Jermaine
• Application Number:
  US10/569,196
• Publication Number:
  US 20070151334A1
• Time in Patent Office: 1,796 Days
• Field of Search: 73146-1468, 340442-447
• US Class Current: 73/146
• CPC Class Codes: B60C 23/066 by monitoring wheel-centre to ground distance
• CPC Class Codes: B60T 2240/03 Tire sensors
• CPC Class Codes: B60T 2240/04 Tire deformation
• CPC Class Codes: B60T 8/1725 Using tyre sensors, e.g. Sidewall Torsion sensors [SWT] for tyre pressure and temperature detection B60C23/00

Abstract

A method for monitoring deformations in a tire of a vehicle wheel, the wheel including the tire and a rim, the method including: providing the wheel with at least two magnetic-field emitters mutually disposed so as to yield a composite magnetic field having one or more space portions where at least one component of the composite magnetic field is substantially null; disposing at least one main magnetic-field sensor substantially in one of the one or more space portions; monitoring variation of the at least one component of the composite magnetic field; and correlating the variation with tire deformations. At least one of the magnetic-field emitters is disposed in contact with the tire. A system for monitoring deformations in a tire of a vehicle wheel includes the wheel, the at least two magnetic-field emitters, and the at least one main magnetic-field sensor.

Claims

1. A method for monitoring deformations in a tyre of a vehicle wheel, the wheel comprising the tyre and a rim, the method comprising:

providing the wheel with at least two magnetic-field emitters mutually disposed so as to yield a composite magnetic field having one or more space portions where at least one component of the composite magnetic field is substantially null;

disposing at least one main magnetic-field sensor substantially in one of the one or more space portions;

monitoring variation of the at least one component of the composite magnetic field; and

correlating the variation with tyre deformations;

wherein at least one of the magnetic-field emitters is disposed in contact with the tyre.

2. The method of claim 1, wherein the at least one main magnetic-field sensor is disposed in a special space portion where all components of the composite magnetic field are substantially null.

3. The method of claim 1, wherein the at least two magnetic-field emitters generate a composite magnetic field having an intensity greater than or equal to 0.01 Gauss and less than or equal to 10 Gauss.

4. The method of claim 1, wherein the variation is correlated using a linear relation.

5. The method of claim 1, wherein the variation is correlated using a quadratic relation.

6. The method of claim 1, wherein the variation is monitored in three spatial directions;

and

wherein the variation is correlated in the three spatial directions.

7. The method of claim 1, further comprising:

disposing at least one magnetic lens;

in a circumferentially and radially external position with respect to the at least two magnetic-field emitters; and

in radially internal position with respect to any metal structure of the tyre.

8. The method of claim 1, wherein the at least one main magnetic-field sensor disposed in a non-rotating portion of the vehicle.

9. The method of claim 1, further comprising:

disposing at least one secondary magnetic-field sensor so as to cooperate with the at least one main magnetic-field sensor.

10. A system for monitoring deformations in a tyre of a vehicle wheel, comprising:

the wheel;

at least two magnetic-field emitters mutually disposed in the wheel so as to yield a composite magnetic field having one or more space portions where at least one component of the composite magnetic field is substantially null; and

at least one main magnetic-field sensor;

wherein the wheel comprises;

the tyre; and

a rim;

wherein at least one of the magnetic-field emitters is disposed in contact with the tyre, and

wherein the at least one main magnetic-field sensor is disposed substantially in one of the one or more space portions.

11. The system of claim 10, wherein the at least one magnetic-field emitter disposed in contact with the tyre is disposed in a crown portion of the tyre.

12. The system of claim 10, wherein the at least two magnetic-field emitters are disposed in contact with the tyre.

13. The system of claim 10, wherein at least one of the magnetic-field emitters is disposed in a radially internal position with respect to any metal structure of the tyre.

14. The system of claim 10, wherein the at least two magnetic-field emitters are elongated elements.

15. The system of claim 10, wherein the at least two magnetic-field emitters are disposed substantially along a circumference of the wheel.

16. The system of claim 10, wherein each of the magnetic-field emitters has a form selected from:

a single piece;

or

multiple pieces.

17. The system of claim 10, wherein the at least two magnetic-field emitters are made of magnetic rubber, and

wherein the magnetic rubber comprises:

a polymer or polymer blend; and

at least one magnetic material.

18. The system of claim 17, wherein the tyre comprises a liner, and

wherein the polymer or polymer blend has an elastic modulus at least 10% lower than an elastic modulus of the liner.

19. The system of claim 17, wherein the polymer or polymer blend comprises halogen-butyl rubbers.

20. The system of claim 17, wherein the polymer or polymer blend comprises halogenated isobutylene-isoprene rubber.

21. The system of claim 17, wherein the at least one magnetic material is present in the magnetic rubber in an amount greater than or equal to 50 phr and less than or equal to 400 phr.

22. The system of claim 17, wherein the at least one magnetic material is a hard magnet material.

23. The system of claim 17, wherein the at least one magnetic material has an isotropic magnetization.

24. The system of claim 17, wherein the at least one magnetic material has an intrinsic coercivity greater than or equal to 100 kA/m.

25. The system of claim 17, wherein the at least one magnetic material has a residual induction (Br) greater than 0.6 Tesla.

26. The system of claim 17, wherein the at least one magnetic material has a Curie temperature greater than 300°

C.

27. The system of claim 10, wherein the at least two magnetic-field emitters are magnetized uniformly.

28. The system of claim 10, wherein a magnetic modulation is induced in the at least two magnetic-field emitters.

29. The system of claim 10, further comprising:

at least one magnetic lens.

30. The system of claim 29, wherein the at least one magnetic lens comprises soft magnetic material.

31. The system of claim 29, wherein a single magnetic lens is provided for the at least two magnetic-field emitters.

32. The system of claim 10, wherein the at least one main magnetic-field sensor is disposed in a non-rotating portion of the vehicle.

33. The system of claim 10, wherein the at least one main magnetic-field sensor is mono-axial, bi-axial or tri-axial.

34. The system of claim 10, further comprising:

at least one secondary magnetic-field sensor.

35. The system of claim 34, wherein the at least one secondary magnetic-field sensor is disposed at least 20 cm away from the at least one main magnetic-field sensor.

36. The system of claim 34, wherein the at least one secondary magnetic-field sensor is disposed less than 3 cm away from the at least one main magnetic-field sensor.

37. The system of claim 34, wherein the at least one secondary magnetic-field sensor cooperates with multiple main magnetic-field sensors.

38. The system of claim 34, wherein the at least one secondary magnetic-field sensor is mono-axial, bi-axial, or tri-axial.

39. The system of claim 34, wherein the at least one secondary magnetic-field sensor is oriented in a manner substantially analogous to:

a corresponding main magnetic-field sensor;

or

corresponding main magnetic-field sensors.