Abstract: 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.

Abstract: 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 W1 and a narrow portion having a groove width W2 narrower than the groove width W1. 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 W1 and a narrow portion having a groove width W2 narrower than the groove width W1. 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.

Abstract: A sipe is provided to a land portion provided to a tread of a pneumatic tire. The sipe includes a slit having a width of 0.6 mm or less. The slit has an arithmetic surface roughness Ra of 1.6 ?m or less on a pair of opposing wall surfaces. A molding die of a pneumatic tire includes a sipe plate to shape a sipe. The sipe plate includes a thin plate having a thickness of 0.6 mm or less. The thin plate has an arithmetic mean roughness Ra of 1.8 ?m or less on a pair of side surfaces. Owing to this configuration, deformation of a land portion when making contact with the ground is suppressed regardless of a sipe provided to the land portion.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: In a pneumatic tire in which a tread with a plurality of grooves 1 and 2 including main grooves 1 extending in the tire circumferential direction formed and in which block 3 is formed on shoulder portions of tread T by grooves 1 and 2, on intersection line L between a surface of tread T and a surface of side portion S, the first sipes 11 extending in the tire circumferential direction R are formed, and the depth direction of the sipes 11 and 12 is parallel to tire equatorial plane C, and the sipes 12 are deeper than the sipes 11 and the sipes 12 are wider than the sipes 11, and height difference between a surface of wearing region 13 and a surface of side portion S is not greater than 2.0 mm.

Abstract: A pneumatic tire has a main groove extending along a tire circumferential direction in a tread surface. A plurality of projections having different heights are provided in a groove bottom of the main groove in such a manner that an outer peripheral surface is inclined so as to repeat trough portions depressed to an inner side in a tire diametrical direction and peak portions protruding to an outer side in the tire diametrical direction along the tire circumferential direction.

Abstract: 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.

Abstract: In a pneumatic tire in which a tread with a plurality of grooves 1 and 2 including main grooves 1 extending in the tire circumferential direction formed and in which block 3 is formed on shoulder portions of tread T by grooves 1 and 2, on intersection line L between a surface of tread T and a surface of side portion S, the first sipes 11 extending in the tire circumferential direction R are formed, and the depth direction of the sipes 11 and 12 is parallel to tire equatorial plane C, and the sipes 12 are deeper than the sipes 11 and the sipes 12 are wider than the sipes 11, and height difference between a surface of wearing region 13 and a surface of side portion S is not greater than 2.0 mm.

Abstract: A plurality of closing cylinder devices are provided between a bolster of a press machine and a bed containing a lower mold of a hydroforming device. An upper mold is attached to a slide of the press machine. The upper mold and lower mold come together to form a cavity having the shape of the exterior of the desired molded product. A closing block, being movable between a first position which is between the slide and a crown of the press machine, and a second position, which avoids the slide, permitting free movement of the slide from the crown to the lower mold. When a material to be hydroformed is place in the lower mold, the upper mold is lowered. The closing block is fit into its first position, thereby restricting movement of the slide in the vertical direction. A inner work pressure is provided by a fluid inside the material to be molded.