Toyo Tire Rubber Co., Ltd.

Toyo Tire Corporation

Shinichi Kaji

Yuichi Nakamura

Harunobu Suita

Hiroaki Sugimoto

A pneumatic tire includes: a tread portion; grooves formed on the tread portion; and land portions defined by the grooves, wherein each of the land portions includes: a pair of side walls which opposedly face each other with the groove sandwiched therebetween; a first projecting ridge formed on one of the pair of side walls; and a second projecting ridge formed on the other side wall, the first projecting ridge and the second projecting ridge extend along the groove, at least one of the first projecting ridge and the second projecting ridge is inclined such that a position of the projecting ridge in a groove depth direction changes along the groove, and the first projecting ridge intersects with the second projecting ridge as viewed in a width direction of the groove.

Pneumatic tire

A sipe is provided to a land portion provided to a tread of a pneumatic tire. The sipe is formed of a wide portion having a groove width Wand a narrow portion having a groove width Wnarrower than the groove width W. The wide portion extends in a sipe depth direction D at both ends in a sipe length direction L and extends in the sipe length direction L at an upper end in the sipe depth direction D. The narrow portion is surrounded by the wide portion on three sides including both sides in the sipe length direction L and an opening side in the sipe depth direction D and extends to a sipe bottom. Consequently, chipping of rubber is suppressed by reducing pulling resistance of a sipe plate at the time of die releasing of a tire while suppressing breakage of the sipe plate.

Pneumatic tire and molding die thereof

Provided is a pneumatic tire where a main groove extending in a tire circumferential direction and a projection projecting toward the inside of the main groove from a groove side wall of the main groove are formed on a tread portion, wherein a projecting amount of the projection from the groove side wall is decreased as the projection extends to a groove bottom of the main groove, the projection terminates at a position outside the groove bottom in a tire radial direction, and a length of the projection along the tire circumferential direction is shortened as the projection extends to a distal end side of the projection in a projecting direction.

Provided is a pneumatic tire where grooves and blocks defined by the grooves are formed on a tread portion, wherein the block includes: a ground contact surface; a hole portion formed in a center portion of the ground contact surface; and sipes extending radially from the hole portion which is the center of radial extension of the sipes, and the sipes are formed such that inner ends of the sipes in a radial direction terminate at a position away from the hole portion, and outer ends of the sipes in the radial direction terminate within the block.

In a pneumatic tire, a sipe formed in a land portion includes a first large width portion having a larger groove width than an opening end formed on a surface of a tread, a neck portion having a smaller groove width than the first large width portion, and a second large width portion having a larger groove width than the neck portion which are disposed in this order on a depth side in a sipe depth direction.

A pneumatic tire has a tread pattern having shoulder blocks arranged in a tire circumferential direction in a shoulder portion of a tread surface, and slits to sectionalize the shoulder blocks. Slit wall surfaces in a trailing side and a leading side of the shoulder blocks are inclined to the slit side from both end portions in a width direction of the shoulder block toward a center portion in the width direction. A notch portion is provided in the center portion in the width direction in the slit wall surface in the trailing side or the leading side of the shoulder block.

Pneumatic tire with tread having notch portions in shoulder block

Tire

In a pneumatic tire in which a tread with a plurality of groovesandincluding main groovesextending in the tire circumferential direction formed and in which blockis formed on shoulder portions of tread T by groovesandon intersection line L between a surface of tread T and a surface of side portion S, the first sipesextending in the tire circumferential direction R are formed, and the depth direction of the sipesandis parallel to tire equatorial plane C, and the sipesare deeper than the sipesand the sipesare wider than the sipesand height difference between a surface of wearing regionand a surface of side portion S is not greater than 2.0 mm.

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Osaka, Japan

Shinichi Kaji