Resilient tires and wheels – Tires – resilient – Pneumatic tire or inner tube
Patent
1988-12-07
1990-08-14
Hoch, Ramon
Resilient tires and wheels
Tires, resilient
Pneumatic tire or inner tube
152534, 152538, 152560, B60C 922, B60C 928
Patent
active
049479156
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a radial ply pneumatic tire(s). More particularly it relates to a radial ply tire intended to bear heavy loads under high inflation pressure, e.g. as used on aircraft.
In the present specification by "radial-ply tire" is meant one having a carcass comprising one or more plies of parallel cords which cross the mid-circumferential plane of the tire at an angle in the range of 70 degrees-90 degrees. If the angle is not 90 degrees the plies are so arranged that the cords in one ply cross the mid-circumferential plane at the opposite bias to the cords in the adjacent ply.
A radial-ply tire for use on aircraft has to meet stringent requirements. The tire has to be provided with a tread reinforcement which, acting with the carcass and the beads, meets the load-bearing requirements for the given overall weight, size and aspect ratio dependent on the actual type of aircraft for which the tire is intended to be fitted. The tire also has to have adequate high speed performance; for example, the tire operating temperature must not be excessively high, otherwise internal damage may occur. The onset of standing waves which are often initiated in the tire shoulder region must be prevented. The tread reinforcement must be constructed to cause the generation of a cornering force necessary to give the tire adequate cornering stability and also be such as to prevent the excessive increase in the diameter of the center of the tread of the tire due to high inflation pressure and centrifugal forces which could otherwise lead to rapid and uneven tread wear.
It is an object of the present invention to provide a tire having a construction which meets the above-mentioned operating requirements as far as possible.
Thus in accordance with the invention a pneumatic radial ply tire comprises a tread, a radial ply carcass anchored to at least one bead core in each bead region of the tire and a tread reinforcement comprising three groups of layers of cord reinforcing fabric; the first, radially inner, group comprising at least two layers of parallel cords extending at a bias angle lying in the range 15 degrees to 60 degrees, each layer being at opposite bias to the adjacent layer and the width of the first group of layers being less than the contact width of the tire tread under the scheduled load and inflation pressure of the tire; a second group of layers, positioned radially outwards of the first group, and comprising at least two layers of parallel cords extending substantially parallel to the mid-circumference of the tire, and the width of the second group of layers being greater than the width of the first group of layers; and a third group of layers, positioned radially outwards of the second group, comprising at least two layers of parallel cords extending substantially parallel to the mid circumferential plane of the tire and having a width which is substantially less than the width of the second group of layers.
Preferably the carcass comprises more than one ply the bias angle of each being less than 90 degrees and typically lying in the range 75 degrees to 85 degrees. A preferred value is 84 degrees but this depends on the speed requirement and aspect ratio of the tire.
Preferably the bias angle of the cords of the layers in the first group is 45 degrees. Preferably also the width of the first group is between 70% and 90% of the tread contact width under the scheduled load and inflation pressure. The first group of layers in the tread reinforcement serves to generate the cornering force and cornering stability necessary for optimum tire performance.
Preferably the width of the second group of layers is at least 1.03 times that of the first group of layers. Preferably also, the width of the second group is no greater than 1.20 times the tread contact width under the scheduled load and inflation pressure. The second group of layers is intended to enhance the speed performance of the tire by reducing the onset of standing waves being initiated from the tire shoulder regions particularly at the higher spe
REFERENCES:
patent: 3831656 (1974-08-01), Senger et al.
patent: 4454903 (1983-05-01), Noel et al.
patent: 4732199 (1988-03-01), Kajiwara
Barlow Stephen
Panikkar Tharamel P. K.
Dunlop Limited
Hoch Ramon
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