The Yokohama Rubber Co., Ltd.

Makoto Takagi

Tatsuo Suzuki

Yukio Kaga

Fumio Tomisawa

A pneumatic radial tire having a carcass layer of cords disposed substantially at a right angle to the circumferential direction, and four belt layers sandwiched between the carcass layer and a tread. A pair of belt layers composed of a second and a third layer in the direction of from the carcass to the tread of the tire have cord layers crossing one another respectively at an angle of 10.degree. to 30.degree. to the circumferential direction, fatigue resistance of the cords of the second layer being significantly greater than fatigue resistance of the cords of the third layer.

Pneumatic radial tire including at least two metallic belt cord layers

A heavy-duty pneumatic radial tire having a bead portion comprising a carcass layer having its respective end portions turned up about a bead core from the inner side to the outer side of the tire and at least two reinforcing layers disposed along a portion of the carcass layer, which tire comprises an inner reinforcing layer having a tenacity of from 30 kg/mm of layer width inclusive to 80 kg/mm of layer width not inclusive, incorporated on the inner side of the bead portion, and an outer reinforcing layer having a greater tenacity than the inner reinforcing layer and of at least 80 kg/mm, of layer width incorporated on the outside of the bead portion, wherein cords in the inner reinforcing layer and those in the outer reinforcing layer are inclined in a same direction relative to the radial direction of the tire, and when mounted on a vehicle the direction of inclination of the cords in the inner and the outer reinforcing layers is opposite the direction of forward rotation of the tire.

Growing community of inventors

Hiratsuka, Japan

Makoto Takagi