Method and system of detection of a run-flat condition of a tire; inserts, wheels and tires designed for such method and system

• US 20050061070A1
• Filed: 10/12/2004
• Published: 03/24/2005
• Est. Priority Date: 07/06/1998
• 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: Dosjoub, Andre, Dufournier, Arnaud
• Granted Patent: US 6,952,956 B2
• Time in Patent Office: Days
• US Class Current: 73/146
• CPC Class Codes: B60C 2019/006 Warning devices, e.g. devices generating noise due to flat or worn tyres
• CPC Class Codes: B60C 23/061 by monitoring wheel speed measuring distance traversed on the ground by vehicles G01C22/00
• CPC Class Codes: B60C 23/062 Frequency spectrum analysis of wheel speed signals, e.g. using Fourier transformation

Abstract

A method of detection of a run-flat condition of a vehicle tire, said tire being mounted on a wheel, wherein: a quantity f(α, t) is sensed, which varies which the angular displacement of the wheel in time; measuring signals are elaborated, which vary with the angular speed of the wheel dα(t)/dt; a quantity characteristic of the dispersion of measuring signals is calculated; an alarm is set off when the characteristic quantity satisfies a given ratio.

Claims

1-27. -27. (Cancelled)

28. A system of detection of a run-flat condition of a vehicle tire mounted on a wheel, the system comprising:

(a) first means for sensing a quantity f(a,t) which varies with the angular displacement of the wheel in time,

(b) second means for;

(i) determining a plurality of signals from that quantity, the signals varying with the angular speed of the wheel dα

(t)/dt, (ii) calculating at least one characteristic quantity of dispersion of the signals, and (iii) setting an alarm condition when the at least one characteristic quantity satisfies a predetermined relationship; and

(c) third means arranged in the mounted tire/wheel assembly to generate variations in the sensed quantity f(α

,t) in the run-flat condition of the tire.

29. A system according to claim 28, wherein the third means generates at least one sinusoidal function, the period of which is a sub-multiple of a turn of the wheel.

30. A system according to claim 29, wherein the third means generates substantially only one sinusoidal function, the period of which is a sub-multiple of a turn of the wheel.

31. A system according to claim 28, wherein, in a vehicle equipped with a wheel antilock device, the first and second means comprise sensors and a computer of the wheel antilock device.

32. A system according to claim 28, wherein the third means comprises a safety insert configured to be radially mounted outside a rim of the wheel, the safety insert including, on its radially outer surface, axially-oriented bars having sides whose inclination from normal to the tread in the longitudinal direction varies as a function of azimuth.

33. A system according to claim 32, wherein the longitudinal inclination of the bars as a function of azimuth is substantially a sinusoidal function whose period is a sub-multiple of a turn of the safety insert.

34. A system according to claim 28, wherein the vehicle tire comprises a tread, two sidewalls, two beads, and support elements that support the tread in case of the run-flat condition, the support elements comprising means for generating rotation speed variations, upon the run-flat condition of the tire.

35. A system according to claim 34, wherein the means for generating rotation speed variations comprises a variation, as a function of azimuth, of a radius under load of the tire, upon running with a tire deflection above a given threshold.

36. A system according to claim 35, wherein the variation, as a function of azimuth, of the radius under load of the tire is at least a sinusoidal function, the period of which is a sub-multiple of a turn of the tire.

37. A system according to claim 28, wherein the third means comprises the wheel, and the wheel comprises means for generating rotation speed variations of the wheel, upon the run-flat condition of the tire.

38. A system according to claim 37, wherein the wheel presents a variation, as a function of azimuth, of the radial height of at least one of its flanges.

39. A system according to claim 38, wherein the variation of radial height of the at least one flange, as a function of azimuth, is obtained by adding a component that at least partially covers a radial end of the flange.

40. A system according to claim 38, wherein the variation of radial height of the at least one flange, as a function of azimuth, is at least a sinusoidal function, a period of which is a sub-multiple of a turn of the wheel.