69results about How to "Improve uneven wear resistance" patented technology

A tread portion of a pneumatic ti re includes inner land portions between outer circumferential main grooves disposed most on tread ground-contact end sides and at least one inner circumferential main groove on the inner side thereof. The inner land portions are divided into inner blocks by inner lateral grooves inclined at an angle α of 10 to 40°. The inner lateral grooves consist of first inner lateral grooves and second inner lateral grooves which are alternately arranged in a circumferential direction. The first inner lateral grooves include a wide-width part connecting to the outer circumferential main groove and a narrow-width part connecting to the inner circumferential main groove.

A pneumatic tire of the invention includes: a stepped-shaped raised area provided in the main groove positioned at a center area of the tire so as to be continued circumferentially of the tire, connected to either the main groove walls, and raised from the groove bottom; and a ridge lower than a tread surface of the tire in each of the main grooves on both outsides of the main groove at the center area of the tire so as to be raised from the center of the groove bottom continuously along the length thereof without being joined with the groove walls, and the angle of inclination of the main groove walls with respect to the normal line of the tangential line on the tread surface of the main groove portion is parallel to each other or is 5° or smaller.

A circumferential sipe extends continuously in the circumferential direction of the tire in the center region of the tread surface section of a rib defined between circumferential grooves. Widthwise sipes are disposed at prescribed intervals in the circumferential direction of the tire in the tread surface section, the widthwise sipes extending in the widthwise direction of the tire in crossing relationship to the circumferential sipe, the widthwise sipes each having opposing terminal ends open to the circumferential grooves. The circumferential sipe changes in depth periodically in such a manner that the circumferential sipe is shallow between adjacent widthwise sipes. The widthwise sipes changes in depth in such a manner that they are greater in depth in the center region and end regions of the tread surface section.

A pneumatic tire is provided in the tread portion with a central land portion between two crown main grooves. The central land portion is provided with notches each having a depth of 55% to 65% of the depth of the crown main groove and having a closed end and an open end opening to the crown main groove.

The maximum axial length of the central notch is 10% to 15% of the maximum axial length of the central land portion, and the circumferential length of the opening is 10% to 15% of one circumferential pitch of the shoulder block row 7R.

The circumferential length of the opening is 15% to 25% of one circumferential pitch of the central notches.

In the pneumatic tire, the blocks above the circumferential reinforcing layer have at least one sipe. Also, the sipe has a bent shape, in a plan view, with two flex points P1, P2, and has a closed structure with two end points Q1, Q2 terminating within the block. Also, the angle α between the line that connects the flex points P1, P2 and the tire circumferential direction is within the range such that 0°≦α≦10°. Also, the angle β1 between the line connecting the flex point P1 and the end point Q1 and the tire circumferential direction, and the angle β2 between the line connecting the flex point P2 and the end point Q2 and the tire circumferential direction are within the range such that 35°≦1≦55° and 35°≦β2≦55°.

A plurality of ribs (9, 11 and 18) extending in a tire circumferential direction (C) are defined in a tire width direction (W) by a plurality of circumferential main grooves (5 and 7). In two or more second ribs (11), a plurality of sipes (19) are formed so as to be spaced apart in the tire circumferential direction (C) and to cut across the ribs. By the plurality of sipes (19), the two or more second ribs (11) are divided into a plurality of divided ribs (21). All intersection angle portions on one side in the tire circumferential direction (C) in each of the divided ribs (21) are formed to have obtuse angles. Only on one side in the tire circumferential direction (C) in each of the divided ribs (21), a runner groove (23) communicated with the corresponding sips (19) is formed so as to cut across the second rib (11).

Disclosed is a pneumatic tire including a straight main groove and two wave-shaped main grooves arranged in the center area of a tread, and diagonal grooves arranged in each shoulder area ranging from each wave-shaped main groove to the outer side of the tire, and extending obliquely outward from the wave-shaped main groove to a direction reverse to the tire rotational direction, the rotational direction being specified for the tire. Each diagonal groove is formed to have a convex protruding toward the outer side of the tire, and the extending end portion of the diagonal groove terminates in the shoulder area. Thus, each shoulder area is provided with a non-block pattern in which a land section continues in the tire circumferential direction. Thereby, the pneumatic tire has increased driving stability and uneven wear resistance while substantially maintaining good drainage performance and noise performance against columnar resonance.

A pneumatic tire includes first lug grooves and second lug grooves shorter than the first lug grooves provided alternately along a circumferential direction in a shoulder region of a tread section, a first connection groove that connects the second lug groove and a tip end part of the first lug groove, and a second connection groove that connects the first lug groove and a tip end part of the second lug groove. An angle of the first connection groove is greater than an angle of the second connection groove, and an inner end portion in the lateral direction of each of first shoulder blocks, each defined by the first lug groove, the second lug groove, and the first connection groove, is disposed closer to the equator side than an inner end portion in the lateral direction of each of second shoulder blocks.

A pneumatic radial tire for a passenger vehicle has a ratio W/L where W is a cross-sectional width and L is an outer diameter. The tire also has a belt-reinforcing layer having a high rigidity and disposed between a belt and a tread.

A shoulder lateral groove 5 comprises an inner lateral groove portion 7 intersecting a shoulder main groove 3S, an outer lateral groove portion 8 intersecting a tread edge (Te), and a sipe portion 9 connecting between the inner lateral groove portion 7 and the outer lateral groove portion 8. The outer lateral groove portion 8 has a bent portion 10 and extends so as to connect between the tread edge (Te) and the sipe portion 9.

A pneumatic tire includes a tread surface having a middle rib defined by a first circumferential groove and a second circumferential groove in its center region. Middle lateral grooves, that obliquely extend in the widthwise direction of the tire, are disposed at predetermined intervals in the tire circumferential direction in the middle rib; only one terminal end of each middle lateral groove communicates with one circumferential groove of the first and second circumferential grooves. An assistant groove is provided between each of adjacent middle lateral grooves; the assistant groove extends in such an inclined manner that the inclination direction thereof with respect to the tire circumferential direction is opposite to that of the middle lateral grooves; a block is defined by the assistant groove, middle lateral grooves and one circumferential groove. The middle lateral grooves each include a first inclined groove portion having an inclination angle a ranging from 35 degrees to 60 degrees and a second inclined groove portion having an inclination angle β ranging from 0 degree to 30 degrees. One terminal end of the assistant groove is located at a position ranging from 20% to 30% of the tire-widthwise length of one middle lateral groove of the adjacent middle lateral grooves from the one terminal end of the one middle lateral groove toward the other terminal end side of the one middle lateral groove in the tire widthwise direction. The other terminal end of the assistant groove is located at a position ranging from 20% to 30% of the tire-widthwise length of the other middle lateral groove of the adjacent middle lateral grooves from the other terminal end of the other middle lateral groove toward the one terminal end side of the other middle lateral groove in the tire widthwise direction.

A pneumatic tire includes a tread portion; three or more circumferential direction grooves; width direction grooves; and lines of land portions. When a tread center area and tread shoulder areas are sectioned at centerlines of the circumferential direction grooves in outermost sides in the tire width direction, a ratio G=(A+B)/X of a sum A+B of a groove area A of the circumferential direction grooves and a groove area B of the width direction grooves to a contact area X of the tread portion is in a range of G≦0.25, a ratio S=B/(A+B) of the groove area B to the sum A+B is in a range of 0.25<S<0.45, a ratio Gs=C/Y of a groove area C of the tread shoulder areas to a contact area Y of the tread shoulder areas is in a range of Gs<0.20, and the ratio G and the ratio Gs have a relation of Gs<G.

A heavy duty pneumatic tire includes a tread portion including a plurality of blocks separated by a plurality of circumferentially extending main grooves and a plurality of lateral grooves. At least one of the blocks is provided with two axially extending sipes to divide the block into a first end portion, a second end portion and a middle portion between the first end portion and the second end portion. The first end portion includes a first projected portion that protrudes outwardly in a block-width direction from the middle portion so as to form a steplike side, and the second end portion includes a second projected portion that protrudes outwardly in an opposite block-width direction to the first projected portion from the middle portion so as to form a steplike side.

A pneumatic tire includes circumferential grooves aligned in a lateral direction and extending in a circumferential direction, lateral grooves aligned in the circumferential direction and extending to cross the circumferential direction, communicating at ends with the circumferential grooves and defining a block-shaped land portion between the circumferential grooves, two narrow grooves aligned in the lateral direction and extending in the circumferential direction, communicating at ends with a lateral groove and dividing the land portion defined by each of the circumferential grooves and each of the lateral grooves into small land portions, the narrow grooves having a smaller groove width than the circumferential grooves and being formed with a bent portion in an intermediate portion, the bent portion being disposed inward in the lateral direction, and bend points of the bent portions being disposed at positions offset from one another in the circumferential direction.

A pneumatic tire includes a shoulder land portion and a narrow groove in a tread surface. The narrow groove extends in the tire circumferential direction and sections the shoulder land portion into a main land portion and a sub land portion. A first groove portion extends from the tread surface toward an inner side in the tire radial direction in parallel to the tire equatorial plane. A second groove portion is provided closer to the inner side in the tire radial direction and the tire equatorial plane side than the first groove portion and extends in parallel to the tire equatorial plane. A coupling portion is connected to an end portion of the first groove portion in the inner side in the tire radial direction and an end portion of the second groove portion in the tread surface side.

A pneumatic tire is provided, the pneumatic tire including a tread portion, sidewall portions, and bead portions, and the pneumatic tire includes, in the tread portion, a center main groove extending in a tire circumferential direction and a shoulder main groove extending in the tire circumferential direction on the outside of the center main groove; a land portion between the main grooves; lug grooves extending inward in a tire lateral direction from the shoulder main groove and terminating without communicating with the center main groove; a bent portion bending toward one side in the tire circumferential direction, at a terminating end of each of the lug grooves; and a raised bottom portion included in the bent portion, creating a level difference with respect to a lug groove, and being shallower than the lug groove.

A pneumatic tire comprises a tread portion provided with crown main grooves, center axial grooves and center blocks including a siped center block with a first sipe. The siped center block has a pair of substantially v-shaped opposite first and second block side walls each having an outwardly protruding vertex. The first sipe has a wavy configuration at least partially. One end of the first sipe is positioned on one side in the tire circumferential direction of the vertex of the first block side wall, whereas the other end of the first sipe is positioned on other side in the tire circumferential direction of the vertex of the second block side wall.