Method and installation for predicting the maximum running distance, in degraded mode, of a mounted assembly

• US 6,820,015 B2
• Filed: 03/10/2003
• Issued: 11/16/2004
• Est. Priority Date: 04/05/2001
• Status: Expired due to Fees

• Current Assignee: Compagnie générale des établissements Michelin
• Original Assignee: Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA)
• Inventors: Thiallier, Daniel, Ferres, Laurent
• Primary Examiner(s): NGHIEM, MICHAEL P
• Application Number:
  US10/384,863
• Publication Number:
  US 20040002820A1
• Time in Patent Office: 617 Days
• Field of Search: 702/34, 702/35, 702/145, 702/148, 702/163, 702/174, 702/181, 702/182, 731/46, 152/155, 152/157, 152/158, 152/512, 152/520
• US Class Current: 702/34
• CPC Class Codes: G01M 17/022 the tyre co-operating with rotatable rolls

Abstract

The present invention concerns a method and an installation for predicting the maximum running distance in degraded mode, without substantial deterioration in the running, of a mounted assembly including a rim, a safety support and a tire mounted on the rim. The method according to the invention includes running the mounted assembly at a reduced or zero inflation pressure or the support mounted on the rim, from a time t₀, at a given load and with a constant speed V, on at least one running surface so that the center (C) of the rim is a point which is substantially invariant during the running, monitoring the variation in a variable R representing the radial loading of the support as a function of the running time t.

Claims

1. A method of predicting the maximum running distance without substantial deterioration in the running conditions, at a reduced or zero inflation pressure, of a mounted assembly, comprising a wheel rim, a safety support mounted on the rim and a tire cover mounted on the rim around the support, the support supporting the tread of the tire cover during the running, wherein said method comprises running on at least one running surface either (1) the mounted assembly at a reduced or zero inflation pressure or (2) the support mounted on the rim, from a time t₀, at a given temperature, at a given load and with a constant speed V, so that the center of the rim is a point which is substantially invariant during said running, monitoring the variation in a variable R representing the radial loading of the support as a function of the reduced or zero pressure running time t, and wherein the method comprises, during said running, implementing the following sequence of steps:

(i) determining a value R₁ attained by said variable R at the end of a predetermined stabilization time t₁ which is such that the direction of variation of said variable R represents a radial loading of said support increasing overall beyond the stabilization time t₁, then

(ii) determining a critical running time t₂ (t₂>

t₁) at the end of which said variable R reaches a critical value R₂ such that R₂=R₁+Δ

R, Δ

R being a value representing a critical increase in the loading of the support with respect to the value R₁ at the end of the stabilization time t₁, and then

(iii) making the running time t₂ correspond to a distance d₂, with d₂=V(t₂−

t₀), representing a prediction of the maximum running distance without substantial deterioration in the running conditions of the mounted assembly.

2. The prediction method according to claim 1, wherein the value Δ

R is such that, at time t₂, the rate of increase |dR/dt| in the loading of the support is greater than a given critical threshold.

3. The prediction method according to claim 1 or 2, wherein the mounted assembly is run on the at least one running surface.

4. The prediction method according to claim 3, further comprising estimating that the maximum running distance, without substantial deterioration in the running conditions, is attained just before smoke is detected inside the mounted assembly.

5. The prediction method according to claim 1 or 2, wherein the support mounted on the rim is run on the at least one running surface.

6. The prediction method according to claim 1, wherein step (ii) is implemented following the variation in said variable R from the time t₁, and predicting that the variable R attains the critical value R₂ at the critical time t₂ substantially when the instantaneous acceleration of the loading d²R/dt² of the support passes through a zero value.

7. The prediction method according to claim 1, wherein said variable R representing the radial loading of the support corresponds to the mean radius of the support during loading, the radius being measured between a first point defining the center of the rim and a second point defining the center of the contact surface between the running surface and the tire cover or the radially external face of the support, according to whether the tire cover or the support is in contact with the running surface.

8. The prediction method according to claim 1, wherein the running surface is in the form of a cylinder with a circular cross section.

9. The prediction method according to claim 8, wherein the cylinder comprises a test drum having a smooth running surface.

10. The prediction method according to claim 8, wherein the cylinder comprises a test drum whose running surface has a plurality of projecting and/or recessed irregularities on its circumference.

11. An installation for predicting the maximum running distance without substantial deterioration in the running conditions, at a reduced or zero pressure, of a mounted assembly, comprising a wheel rim, a safety support mounted on the rim and a tire cover mounted on the rim around the support, the support supporting the tread of the tire cover during the running, said installation comprising:

at least one running surface, and one or more running stations which are each intended for the running on said at least one running surface either of (1) said mounted assembly or (2) said safety support mounted on a wheel rim, from a time t₀, at a given temperature, at a given load and with constant speed V, the center of the mounted assembly or of the support being a point which is substantially invariant during the running on said at least one running surface;

detection means connected to said at least one running station for detecting at all times, during the running on said at least one running surface, information representing the effects caused by said running, comprising at least one item of information representing the radial loading of the support at all times; and

a unit for controlling the starting of the running according to predetermined running parameters, comprising a running speed V and a load to be applied to the support during running, in order to receive said information from said detection means and to store said information, and to control the stopping of the running if at least one of said items of information reaches a predetermined critical value.

12. An installation according to claim 11, wherein said detection means comprise a loading sensor which is designed to provide at all times a support radius value during loading which represents the mean radial loading of said support during running, said radius during loading being measured between a first point defining the center of the rim and a second point defining the center of the contact surface between said running surface and the tire cover or the support, whichever is being run on said running surface.

13. An installation according to claim 11 or 12, wherein said detection means comprise a smoke detector for detecting the presence of smoke inside the mounted assembly during running at reduced or zero pressure, and further comprising suction means provided inside the running station or stations in order to suck the air included inside the mounted assembly in the direction of said smoke detector.