The Yokohama Rubber Co., Ltd.

Isamu Kishizoe

Yoshimasa Hashimoto

Atsushi Tanno

Izumi Kuramochi

Takumi Morito

Kotaro Iwabuchi

Norifumi Kameda

Koji Watanabe

Ryosuke Nukushina

Yousuke Sakamoto

Masaaki Miyoshi

Yukihiko Ohki

Kouji Watanabe

In a pneumatic tire, a block includes recess/protrusions on a road contact surface. Additionally, a recess/protrusion height of the recess/protrusions is from 0.1 mm to 1.0 mm. A width of the recess/protrusions is from 0.1 mm to 0.8 mm. A recess/protrusion region is where an arrangement interval between adjacent recess/protrusions is not greater than 1.2 mm. A smooth region other than the recess/protrusion region has an arithmetic mean roughness of the road contact surface of the block not greater than 50 μm. A lateral length of the road contact surface of the block in a tire lateral direction is defined. In this case, the block includes the recess/protrusion region and the smooth region in an optional cross-section in a lateral range of not less than 40% of a lateral length of the road contact surface of the block.

Pneumatic tire

In a stud pin, a flange contour shape of a lower flange is an anisotropic shape in which, among imaginary rectangles circumscribing the contour shape, the smallest rectangle includes short sides and long sides having different lengths. The flange contour shape includes first recess portions on each of portions of the flange contour shape extending along the short sides, the first recess portions being curved toward a centroid of the flange contour shape, and the flange contour shape includes a second recess portion on portions of the flange contour shape extending along the long sides, the second recess portions being curved toward the centroid of the flange contour shape. A body contour shape of a body portion is a polygonal shape including vertex angles in a same number as the first and second recess portions, and the vertex angles are disposed facing the first and second recess portions.

Stud pin and stud tire

A pneumatic tire includes two circumferential main grooves disposed in the region on one side of a tire equatorial plane as a boundary and a land portion defined by the two circumferential main grooves. The land portion includes a circumferential narrow groove extending in the tire circumferential direction and sets of a first and a second lug groove extending in the tire lateral direction through the circumferential narrow groove. The first lug groove includes an end portion that opens to the edge portion on one side of the land portion and another end portion that terminates within the land portion. The second lug groove includes an end portion that opens to the edge portion on the other side of the land portion and an end portion that terminates within the land portion. The first lug groove and the second lug groove are alternately disposed in the tire circumferential direction.

A modulus at 300% elongation of a cap tread ranges from 3.0 Mpa to 7.0 Mpa, a modulus at 300% elongation of a undertread ranges from 10.0 Mpa to 20.0 Mpa, and a modulus at 300% elongation of an earthing tread ranges from 10.0 Mpa to 20.0 Mpa. Additionally, an earthing tread is made from a rubber material with a volume resistivity of 1&#xd7;10{circumflex over (&#x2003;)}7&#x3a9;&#xb7;cm or less. The undertread includes a thickened portion in a region between the earthing tread and an edge portion of a block. The gauge of the undertread gradually increases from the earthing tread toward the edge portion of the block due to the thickened portion.

The pneumatic tire includes: a belt layer, a belt reinforcing layer, a tread portion, sidewall portions, a rim cushion rubber, and an electrically conductive rubber disposed in the rim cushion rubber and includes a first end in contact with a rim and exposed on an outer surface of the rim cushion rubber and a second end in contact with a tire component adjacent to the rim cushion rubber. The electrical resistance value of the electrically conductive rubber and a portion of the tread portion is 1&#xd7;10&#x3a9;&#xb7;cm or less. The electrical resistance value of the tire component, a coating rubber of the belt layer, and a coating rubber of the belt reinforcing layer is from 1&#xd7;10&#x3a9;&#xb7;cm to 1&#xd7;10&#x3a9;&#xb7;cm. The electrical resistance value of the rim cushion rubber and a side rubber of the sidewall portions is 1&#xd7;10&#x3a9;&#xb7;cm or greater.

Pneumatic tire with electrically conductive rubber within rim cushion rubber

In a pneumatic tire, one end of a first lug groove opens to an edge of an inner second land on the ground contact edge side, and at the other end terminates within the inner second land. One end of the second lug groove opens to the edge of the inner second land on a equatorial plane edge side, and the other end terminates within the inner second land. The first and second lug grooves are alternately arranged in the circumferential direction. In a region on the outer side in the width direction, a circumferential main groove on the equatorial plane side defining the outer second land has a bent shape with an amplitude in a lateral direction, and includes an acute angle bend bending at an edge on the equatorial plane side. The outside second land includes a lug groove opening to a position facing the bend.

In a pneumatic tire, a modulus at 300% elongation of a cap tread ranges from 3.0 Mpa to 7.0 Mpa, and the modulus at 300% elongation of an undertread ranges from 10.0 Mpa to 20.0 Mpa. Additionally, an earthing tread is made from a rubber material with a volume resistivity of 1&#xd7;10{circumflex over (&#x2003;)}7 &#x3a9;&#xb7;cm or less. The earthing tread is made from the same rubber material as the undertread and has an integral structure with the undertread.

A pneumatic tire includes a tread portion; sidewall portions; bead portions; a carcass layer disposed extending between the pair of bead portions; a belt layer of a plurality of layers disposed on an outer circumferential side of the carcass layer in the tread portion; and a band-like noise absorbing member adhered to a region corresponding to a tire inner surface of the tread portion along the tire circumferential direction interposed by an adhesive layer. The pneumatic tire further includes a belt cover layer being disposed on an outer circumferential side of the belt layer across an entire width of the belt layer, the belt cover layer including organic fiber cords arranged in the tire circumferential direction; and a rate of change of a dynamic loaded radius when traveling at 270 km/h with respect to a dynamic loaded radius when traveling at 30 km/h being restricted to 2.0% or less.

A pneumatic tire includes: a rim cushion rubber disposed in a bead portion where the bead portion and a rim are in contact with each other; an electrically conductive rubber disposed in the rim cushion rubber, the electrically conductive rubber having an electrical resistance value lower than that of the rim cushion rubber, and including a first end exposed on an outer surface of the rim cushion rubber in contact with the rim, and a second end disposed in contact with a tire component adjacent to the rim cushion rubber; and an ground tread rubber disposed in a tread portion passing through a cap tread rubber and an undertread rubber of the tread portion, the ground tread rubber having an electrical resistance value lower than that of the cap tread rubber.

The present technology provides a pneumatic tire having a strip-shaped sound-absorbing member bonded on the inner surface of the tire includes a plurality of belt layers, two or more belt cover layers, one or more belt edge cover layers, and a thread rubber layer. The thickness of the tread rubber layer is substantially uniform in the region X where the sound-absorbing member is located so that the difference between the thickness tat an end of the sound-absorbing member and the thickness tat the position of the tire equator is equal to or less than 0.5 mm. The thickness of the tread rubber layer is smaller in the region Y where the belt edge cover layer is located than in the region X so that the difference between the minimum value tof the thickness in the region Y and the thickness tranges from 1.0 to 4.0 mm.

Pneumatic tire with specified tread rubber layer thickness and sound-absorbing member width

A pneumatic tire includes a carcass layer, a belt layer, a tread rubber having a cap tread and an undertread, a pair of side wall rubbers, a pair of rim cushion rubbers, and a grounding tread that is exposed to a road contact surface of the tread rubber and that penetrates the cap tread and the undertread to contact the belt layer in an electrically conductive manner. The grounding tread includes a widened portion having a cross-sectional area that widens toward a contact surface with the belt layer at the contact portion with the belt layer. The widened portion of the grounding tread has a profile shape that bulges outward in a tire width direction.

Pneumatic tire having specified grounding tread

A pneumatic tire including a plurality of circumferential main grooves extending in a tire circumferential direction and a plurality of land portions partitioned and formed by these circumferential main grooves in a tread portion. Additionally, the plurality of land portions have a plurality of sipes, respectively. Moreover, not less than 90% of the sipes disposed in an inner side region are constituted by two-dimensional sipes and not less than 90% of the sipes disposed in an outer side region are constituted by three-dimensional sipes. Furthermore, the tread portion has a cap rubber and an under rubber. A rubber hardness H1at &#x2212;10&#xb0; C. and a rubber hardness H2at 20&#xb0; C. of the cap rubberin the inner side region, and a rubber hardness H1at &#x2212;10&#xb0; C. and a rubber hardness H2at 20&#xb0; C. of the cap rubberin the outer side region have relationships such that H1&#x3c;H1and H2&#x3c;H2.

A pneumatic tire including a plurality of circumferential main grooves extending in a tire circumferential direction and a plurality of land portions partitioned and formed by these circumferential main grooves in a tread portion. Additionally, the plurality of land portions have a plurality of sipes, respectively. Moreover, not less than 90% of the sipes disposed in an inner side region are constituted by two-dimensional sipes and not less than 90% of the sipes disposed in an outer side region are constituted by three-dimensional sipes. Furthermore, the tread portion has a cap rubber and an under rubber. A rubber hardness Hat &#x2212;10&#xb0; C. and a rubber hardness Hat 20&#xb0; C. of the cap rubberin the inner side region, and a rubber hardness Hat &#x2212;10&#xb0; C. and a rubber hardness Hat 20&#xb0; C. of the cap rubberin the outer side region have relationships such that H&#x3c;Hand H&#x3c;H.

A pneumatic tire including a plurality of circumferential main grooves extending in a tire circumferential direction and a plurality of land portions partitioned and formed by these circumferential main grooves in a tread portion. Additionally, each of these land portions has a plurality of sipes, respectively. Moreover, not less than 90% of the sipes disposed in the inner side region are constituted by two-dimensional sipes and not less than 90% of the sipes disposed in the outer side region are constituted by three-dimensional sipes. The left and right shoulder land portions each have a plurality of lug grooves arranged in the tire circumferential direction. A pitch number Nof the lug grooves in the shoulder land portion on the inner side region side and a pitch number Nof the lug grooves in the shoulder land portion on the outer side region side have a relationship such that N&#x3e;N.

A pneumatic tire having a tread portion, side wall portions, and bead portions includes at least one row of blocks constituted by a plurality of blocks aligned in a tire circumferential direction formed in a vehicle inner side region and a vehicle outer side region of the tread portion. Sipes extend in a tire width direction in each of the blocks. A pitch count of the blocks constituting the row of blocks in the vehicle inner side region is greater than the pitch count of the blocks constituting the row of blocks in the vehicle outer side region. Sipes formed in the blocks in the vehicle outer side region are provided with a structure extending in a linear manner along the depth direction thereof and sipes formed in the blocks in the vehicle inner side region are provided with a structure extending while curving along the depth direction thereof.

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Hiratsuka, Japan

Isamu Kishizoe