The Yokohama Rubber Co., Ltd.

The Yokohama Runner Co., Ltd.

Masahiro Ebiko

Hiroshi Tokizaki

Takumi Morito

Kenichiro Endo

Takeshi Masatomo

Hiroyuki Kojima

Yukio Kuroda

Mitsutoshi Saeki

Sadakazu Takei

Izumi Kuramochi

Kohtaroh Iwabuchi

Tomoyuki Matsumura

Kensuke Saitou

Yasujiro Daisho

Isamu Irie

Richiro Mama

Disclosed is a pneumatic tire including: in a tread surface of a tread portion, a pair of main grooves (center main groove and shoulder main groove) arranged side by side in a tire lateral direction and extending in a tire circumferential direction; land portions (middle land portion) defined by the main grooves; a plurality of lug grooves arranged side by side in the tire circumferential direction and bent and folded back, each of the lug grooves including one end communicating with the shoulder main groove, the other end terminating within the middle land portion, and a bending point in a middle of a path from one end to the other end; and sipes extending across the lug grooves, at least one side of the sipe with respect to the lug groove being formed in a zigzag shape.

Pneumatic tire

A pneumatic tire includes: main grooves in a tread, extending in a circumferential direction in alignment in a lateral direction, defining a center land on an equatorial plane and middle lands on outer sides in the lateral direction; a sipe formed in the center land communicating with a center main groove and terminating within the center land, the sipe bending halfway through its length; a circumferential narrow groove in each of the middle lands dividing the middle lands into a rib-shaped middle inner land and a middle outer land; and lug grooves formed in the middle outer land in alignment in the circumferential direction, communicating with a shoulder main groove and the circumferential narrow groove and dividing the middle outer land into blocks. A width dof the middle inner land and a groove width dof the circumferential narrow groove satisfy a relationship of 0.1&#x2264;d/d&#x2264;0.4.

A pneumatic tire in which: a carcass layer is laid between paired bead sections; a belt layer is buried, on the outer peripheral side of the carcass layer, in a tread section; and multiple main grooves extending in a tire circumferential direction are provided in the tread section. In the pneumatic tire, a maximum groove depth of each of the main grooves is 8.5 mm to 15.0 mm, a ratio &#x3b1; of a section height SH of an actual tire to a section height SHcalculated from a tire size is set in a range of 0.97&#x2266;&#x3b1;&#x2266;0.99, a contact area ratio is 65% to 70% under a measurement condition where an air pressure is 200 kPa and a load is 50% of a load carrying ability with the air pressure of 200 kPa, and an average contact pressure P is 300 kPa to 400 kPa under the measurement condition. The tire achieves enhanced wet performance without increasing tire weight.

Pneumatic tire having ratio of actual section height to calculated section height

A pneumatic tire includes, in a tread portion, a pair of circumferential main grooves extending and a land portion provided between the pair of circumferential main grooves and extending in the tire circumferential direction. The land portion includes a bulging portion bulging in a second arc shape in a tire radial direction as a sectional outline of a tread surface of the land portion and chamfered portions connected to the bulging portion and extending straight toward respective groove walls of the circumferential main grooves. A portion of the bulging portion bulges in the tire radial direction with respect to a virtual tread profile line which is determined by a first arc shape in a sectional shape of the tread portion. A maximum bulging amount is 0.1 to 0.8 mm. The virtual tread profile line extends across the chamfered portions.

Provided is a pneumatic tire which achieves both of excellent wet traction and wear resistance from an early stage to an advanced stage of wear. Multiple dent parts are formed, at certain intervals in a tire circumferential direction, in both side walls of each of at least two land portions of multiple land portions being formed in a tread surface and extending in the tire circumferential direction. Each of the dent parts has a smaller depth than main grooves that define the land portion where this dent part is formed. Multiple sipes are formed to traverse the land portion in a tire width direction between the right and left dent parts opposed to each other. Each of the sipes has a greater depth in both end regions opening to the dent parts than in a center region thereof.

Pneumatic tire with tread having dent parts and sipes

A pneumatic tire includes a plurality of circumferential grooves and a first land portion. The circumferential grooves extend continuously in a tire circumferential direction. The first land portion extends in the tire circumferential direction between a pattern end and one of the circumferential grooves in a shoulder region located outside the circumferential grooves in a tire width direction. The first land portion has first lug grooves extending from the pattern end in the tire width direction and closed without communicating with the circumferential grooves are arranged in the tire circumferential direction. At least one circumferential groove is wave-shaped with a constant groove width in the tire width direction at a tread surface and formed in a wave shape in the circumferential direction at the tread surface and groove bottom. The wave-shaped circumferential groove has a shorter cycle length of waves at the groove bottom than at the tread surface.

Pneumatic tire with tread having wave shaped circumferential groove

A pneumatic tire is configured such that: paired first main grooves extending in a tire circumferential direction are provided on the two sides of a tire equator line in a tread portion, respectively; a distance between a center position of each first main groove and the tire equator line is set at 8% to 20% of a ground contact width W; a first land portion is defined between these first main grooves; multiple sub-grooves each having a curved shape are formed in each of both edge portions of the first land portion at intervals in the tire circumferential direction; one end of each sub-groove is opened to the corresponding first main groove, and the other end of the sub-groove is terminated inside the first land portion; a rib portion continuously extending in the tire circumferential direction is formed in an area of the first land portion on the tire equator line; and a relation between a length (L) of a center line of each sub-groove and a pitch length (P) of the sub-grooves in the tire circumferential direction satisfies 1.1&#xd7;P&#x2266;L&#x2266;2.0&#xd7;P.

Pneumatic tire with tread having rib portion, sub-grooves and sipes

A pneumatic tire has no spew or no spew trace on a sidewall surface of the pneumatic tire and reduces air resistance. The tire includes a plurality of dimple-like recesses and a plurality of linear valley portions. The dimple-like recesses are provides in a first region including a tire maximum width position of the sidewall surface of the tire. The linear valley portions which are formed by serration of the sidewall surface, extend linearly in one direction in the first region and provided around each of the recesses so as to enclose each of the recesses. When a size of an occupied area of each of the recesses on the sidewall surface is represented by an equivalent diameter of a circle, an interval distance between the linear valley portions is smaller than the equivalent diameter.

A pneumatic tire has a tread pattern which comprises at least three circumferential grooves with a groove width of 6 to 18 mm and a groove depth of 6.0 to 16.0 mm extending in a tire circumferential direction, wherein, on groove walls on both sides forming the at least three circumferential grooves, first inclined walls inclined by an inclination angle of 5 to 20 degrees with respect to the tire circumferential direction and second inclined walls inclined by an inclination angle of 0 to 45 degrees with respect to a tire width direction are provided so as to be successively connected in the tire circumferential direction so that positions of groove ends in the tire width direction vary in the tire circumferential direction.

Pneumatic tire with tread pattern including land portions having rib-like configurations

A pneumatic tire includes a tread portion on each side of the equatorial plane. At least two circumferential main grooves and three land portions are formed in the tread portion. In a cross section in a meridian direction of the pneumatic tire, profile lines of the land portions form arcs, and an intersection of extension lines of profile lines of adjacent land portions forms an inflection point in a circumferential main groove. Tensile strength of a reinforcing layer in the land portions is larger than that in the circumferential main groove having the inflection points.

Disclosed is a pneumatic tire including a plurality of land portions and a plurality of fine grooves. The plurality of land portions are formed of blocks and a rib, and are defined in a tread part of the pneumatic tire. The fine grooves with a depth of 0.1 mm to 0.8 mm, a width of 0.1 mm to 0.8 mm and a pitch of 0.5 mm to 2.0 mm are formed in the tread surface of each of the land portions to be inclined at an angle of 42&#xb0; to 60&#xb0; relative to the circumferential direction of the tire. The inclined directions of the fine grooves relative to the circumferential direction of the tire are reverse to each other on the left and right sides of the equator of the tire.

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Hiratsuka, Japan

Masahiro Ebiko