Patent ID: 6467518
Filing Date: 2002-10-22
Classification: B60C,Y10T

Abstract:
A toric membrane of reinforced rubber, used as a support means for the tread of a tire and forming with said tire and its mounting rim a rolling assembly which can roll when the tire is subject to a loss of pressure, the rim having a nominal diameter DS and a flange having an outer diameter DR, the tire having a loaded radius RE when used at the recommended pressure and defining with the rim an internal pressurized cavity, the toric membrane being located within the tire cavity and inflated to a pressure p0 greater than the pressure p1 of the cavity of the tire, and, so inflated, having a crown radius RM less than the loaded radius RE of the tire, said membrane having a crown reinforced by at least two plies of cords or cables which are parallel to each other within each ply and are crossed from one ply to the next, said crown of said membrane furthermore comprising a hooping reinforcement composed of at least one ply of cords or cables oriented circumferentially and having a breaking load under tension per widthwise cm of ply at least equal to the sum of (1) the tension due to the product of the crown radius RM times the pressure per cm2 of surface area of the ply equivalent to a tension per widthwise cm of ply due to the maximum centrifugal force to which the tire is subject, and (2) the tension due to the pressure difference p0âˆ’p1 existing during normal travel, but less than the sum of (1) as aforesaid and (3) a greater pressure difference p0âˆ’pâ€²1 resulting from a loss of inflation pressure in the tire cavity, said membrane having sidewalls reinforced by at least one ply, wherein, viewed in meridian section, each sidewall ply is wound in a bottom part of the sidewall around an annular reinforcement element, the internal diameter of each annular reinforcement element being between a value equal to DR and a value equal to DS and the constitution and transverse dimensions of each annular reinforcement element being such that breaking load thereof under tension is greater than that of the hooping reinforcement at a pressure difference p0âˆ’pâ€²1, existing in the case of the tire cavity undergoing a loss of inflation pressure, greater than the initial pressure difference p0âˆ’p1, said each sidewall ply not being integral with said each annular reinforcement element, and said each sidewall ply having within each of the sidewalls a meridian length such that the meridian profile thereof in the inflated state of the toric membrane restrains the outer sidewall of the toric membrane against contact with the inner sidewall of the tire radially outside a position defined by the diameter DS+2(DRâˆ’DS).