Bridgestone Corporation

Hiroshi Nakata

Takashi Ono

Makoto Tsuruta

Yusuke Yoshikawa

Takashi Oono

Seiji Yamada

Hideaki Minowa

The present invention relates to a method of forming at least one circumferential belt layer of a pneumatic tire comprising: winding the strip for a half length of an outer circumferential length of the crown portion of the carcass along the tire equatorial plane from a widthwise inner side of the belt end region; winding the strip for the remaining half length while shifting the strip for the width of the strip from a widthwise inner to outer side; winding the strip for the outer circumferential length of the crown portion of the carcass along the tire equatorial plane; winding the strip for the half length of the outer circumferential length of the crown portion of the carcass while shifting the strip for the width of the strip from the widthwise outer to inner side; and winding the strip for the remaining half length along the tire equatorial plane.

Pneumatic tire and method of forming circumferential belt layer of the same

A belt width of an intersecting belthaving the maximum belt width is set to 80% or more of the maximum width of a carcass line; a difference in belt widths between the intersecting beltand an intersecting beltis set in the range of 10 mm to 50 mm on one side of the belt in the width direction; the intersecting beltis not narrower than the circumferential belt, and the circumferential beltis not narrower than the intersecting belt; and a pneumatic tire according to the present invention has an interposed rubberhaving a thickness increasing toward the widthwise outer side of the tire to be 3 mm or more, and a side-lower rubberhaving an elastic modulus less than the elastic modulus of a coating rubber coating the circumferential belt

Pneumatic tire

In a heavy duty radial tire, a reinforcement belt outward in a radial direction of the tire and a high-strength belt inward in the radial direction are arranged between a radial carcass and a tread rubber , and an intersect angle between cord of an innermost wide-width slant cord layer in the reinforcement belt and cord of an outermost narrow-width slant cord layer in the high-strength belt is not less than 10&deg; at an acute angle side, and narrow-width slant cord layers of the high-strength belt in the tire mounted onto a rim and inflated under a maximum air pressure have a width corresponding to 20&tilde;60% of a ground contact width of the tread rubber , and inclination angles of cords with respect to an equatorial plane of the tire are not more than 15&deg;, and a rubber gauge t of a first rubber layer between cord of an innermost wide-width slant cord layer and cord of an outermost narrow-width slant cord layer is 0.9&tilde;3.0 times a cord diameter D of the slant cord layer

Heavy duty radial tire

A heavy duty pneumatic radial tire comprises a carcass ply, a belt disposed at an outside of the carcass ply in the radial direction and comprised of two or more belt layers, at least one auxiliary belt layer disposed in a widthwise central portion of the belt at a width narrower than that of the belt, and a tread, wherein when the tire is mounted onto a design rim defined in TRA standard and inflated under an internal pressure corresponding to 10% of an air pressure defined in the TRA standard, a radius of curvature of an outer profile at both side regions of the tread (Rs) is made larger than a radius of curvature of the outer profile at a central region of the tread (Rc).

Heavy duty pneumatic radial tire having radius of curvature at side regions and radius of curvature at central portion

A heavy duty pneumatic radial tire comprises a radial carcass, a main cross belt and a tread portion, in which the main cross belt is formed by laminating at least three rubberized cord layers so that the cords in each layer are parallel to each other but the cords between the adjoining layers are crossed with each other and extend in opposite directions with respect to an equatorial line of the tire. In such a tire, a pair of cushion rubbers are arranged between the adjoining rubberized cord layers constituting the main cross belt at their both end portions by setting a position relation between mutual cushion rubbers at both belt ends to an optimum value to thereby prevent or control the occurrence of the belt end separation failure.

Growing community of inventors

Kodaira, Japan

Hiroshi Nakata