Heavy duty pneumatic radial tire
AssigneeBridgestone Tire Company Limited
InventorsKenichi Motomura, Hiroshi Ogawa, Akira Yamamoto, Noriyuki Hagita
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Abstract
A novel tread pattern is disclosed, which can give high performances on wet road at both the straight running and the cornering under a low load, particularly no load, to a heavy duty pneumatic radial tire without sacrificing the performances on wet road under normal load. The tread pattern comprises at least 4 lands defined by at least 3 main grooves, wherein a pair of first group lands arranged on the outermost side regions of the tread have substantially continuous along the the circumferential direction of the tread and the remaining lands located between the first group lands have notches arranged thereon in their lateral direction.
Claims13
A heavy duty penumatic radial tire, comprising;
- a body reinforcement consisting of a carcass and a belt, an outer rubber layer covering the body reinforcement, and a tread formed by covering the crown portion of the body reinforcement by the outer rubber layer;
- said carcass consisting of at least one rubberized cord layer having tire cords arranged therein in the substantial radial plane of the tire;
- said belt consisting of at least two metal cord layers arranged on the outer side of the carcass such that the metal cords in the adjacent cord layers are crossed with each other at a relatively small inclined angle with respect to the equatorial line of the tire;
- said tread having at least four lands formed thereon and separated from each other by at least three main grooves extending continuously in zigzag form along the circumferential direction of the tread, each groove having a width of 3-10% based on the width of the tread;
- and said at least four lands having a pair of first group lands which are formed at the outermost sides of the tread and are substantially continuous along the circumferential direction of the tire;
- notches arranged at least at the edge portions of the lands which edge portions are other than those adjacent to the main grooves defining the above described first group lands, and being opened to the main grooves in an opening width of 0.5-4% in each notch based on the width of the tread such that the land near the center portion of the tread has a shear resistance in circumferential and axial directions less than that of the land near the side portion of the tread, each of a pair of second group lands arranged adjacent to and at the inner side of the main grooves defining the above described first group lands being softer at the inner portion thereof than at the outer portion thereof, and the notch, which is arranged on the second group land and is opened to the main groove adjacent to and at the inner side of the second group land, is increased in its depth from the center portion towards the edge portion of the land and is opened to the main groove.
Dependencies are inferred from the claim text.