Sumitomo Rubber Industries Limited

Akira Kajikawa

Kenji Saito

Kazuo Asano

Yoshihide Kojima

Yasuo Wada

Atsushi Yamahira

Akihiro Nakatani

Hiroyuki Noma

Kazuhiko Kawamura

Hiroshi Itho

Saneto Saito

A belted radial ply tire which comprises a bead core disposed in each bead portion, a carcass extending between the bead portions and turned up around the bead cores, and a belt comprising at least two cross plies disposed radially outside the carcass and inside the tread, and in a state that the tire is mounted on its regular rim and inflated to its regular inner pressure but loaded with no tire load, the effective belt width BW of the effective belt part BE of the belt, the belt edge camber height CH of the belt, and the tire section width TW satisfy 2.50(BW/TW)-1.25&lt;CH&lt;13.3(BW/TW)-4.65.

Radial tire with even wear at tread shoulders

A pneumatic radial tire has a tread surface extending along a specific curvature plane which includes a first arc with the radius R1 having a center on the tire's equatorial plane and passing through the tire's equatorial point, a second arc with the radius R2 having a center on the tire's equatorial plane and intersecting with the first arc at an intersection distant from the tire's equatorial plane by 0.2 to 0.25 times the tire width SW, and a third arc with the radius R3 passing through a ground contact outer edge point of the ground contact surface, when a standard load is applied, and a belt intermediate height point on the tread surface. In the specific curvature plane, the curvature radius ratio R2/R3 is set in a range from 4 to 12, and the curvature radius ratio R1/R2 is set in a range from 1.2 to less than 1.6 when the aspect ratio H/SW is 0.70 or more. The tread surface is provided with a main circumferential groove, preferably having a groove width of 0.06 to 0.10 times the tire width SW, extending near the intersection of the first arc and the second arc in the tire circumferential direction for dividing the tread surface into the crown part and an outer shoulder part. Narrow lateral grooves crossing the tire circumferential direction divide the crown part and shoulder part into blocks.

Pneumatic radial tire with high cornering and steering stability

A pneumatic radial tire has a tread surface extending along a specific curvature plane which includes a first arc with the radius R1 having a center on the tire's equatorial plane and passing through the tire's equatorial point, a second arc with the radius R2 having a center on the tire's equatorial plane and intersecting with the first arc at an intersection distant from the tire's equatorial plane by 0.2 to 0.25 times the tire width SW, and a third arc with the radius R3 passing through a ground contact outer edge point of the ground contact surface, when a standard load is applied, and a belt intermediate height point on the tread surface. In the specific curvature plane, the curvature radius ratio R2/R3 is set in a range from 1.2 to less than 1.6 when the aspect ratio H/SW is 0.70 or more. The tread surface is provided with a main circumferential groove, preferably having a groove width of 0.06 to 0.10 times the tire width SW, extending near the intersection of the first arc and the second arc in the tire circumferential direction for dividing the tread surface into the crown part and an outer shoulder part. Narrow lateral grooves crossing the tire circumferential direction divide the crown part and shoulder part into blocks.

A pneumatic radial tire has a tread surface extending along a specific curvature plane which includes a first arc with the radius R1 having a center on the tire's equatorial plane and passing through the tire's equatorial point, a second arc with the radius R2 having a center on the tire's equatorial plane and intersecting with the first arc at an intersection distant from the tire's equatorial plane by 0.2 to 0.25 times the tire width SW, and a third arc with the radius R3 passing through a ground contact outer edge point of the ground contact surface, when a standard load is applied, and a belt intermediate height point on the tread surface. In the specific curvature plane, the curvature radius ratio R2/R3 is set in a range from 4 to 12, and the curvature radius ratio R1/R2 is set in a range from 1.6 to less than 2.6 when the aspect ratio H/SW is more than 0.55 and less than 0.70. The tread surface is provided with a main circumferential groove, preferably having a groove width of 0.06 to 0.10 times the tire width SW, extending near the intersection of the first arc and the second arc in the tire circumferential direction for dividing the tread surface into the crown part and an outer shoulder part. Narrow lateral grooves crossing the tire circumferential direction divide the crown part and shoulder part into blocks.

A pneumatic radial tire has a tread surface extending along a specific curvature plane which includes a first arc with the radius R1 having a center on the tire's equatorial plane and passing through the tire's equatorial point, a second arc with the radius R2 having a center on the tire's equatorial plane and intersecting with the first arc at an intersection distant from the tire's equatorial plane by 0.2 to 0.25 times the tire width SW, and a third arc with the radius R3 passing through a ground contact outer edge point of the ground contact surface, when a standard load is applied, and a belt intermediate height point on the tread surface. In the specific curvature plane, the curvature radius ratio R2/R3 is set in a range from 4 to 12, and the curvature radius ratio R1/R2 is set in a range from 2.6 to 4.6 when the aspect ratio H/SW is 0.55 or less. The tread surface is provided with a main circumferential groove, preferably having a groove width of 0.06 to 0.10 times the tire width SW, extending near the intersection of the first arc and the second arc in the tire circumferential direction for dividing the tread surface into the crown part and an outer shoulder part. Narrow lateral grooves crossing the tire circumferential direction divide the crown part and shoulder part into blocks.

A pneumatic radial tire has a tread surface extending along a specific curvature plane which includes a first arc with the radius R1 having a center on the tire's equatorial plane and passing through the tire's equatorial point, a second arc with the radius R2 having a center on the tire's equatorial plane and intersecting with the first arc at an intersection distant from the tire's equatorial plane by 0.2 to 0.25 times the tire width SW, and a third arc with the radius R3 passing through a ground contact outer edge point of the ground contact surface, when a standard load is applied, and a belt intermediate height point on the tread surface. The tread surface is provided with a main circumferential groove, preferably having a groove width of 0.06 to 0.10 times the tire width SW, extending near said intersection of the first arc and the second arc in the tire circumferential direction for dividing the tread surface into the crown part and an outer shoulder part. Narrow lateral grooves crossing the tire circumferential direction divide the crown part and shoulder part into blocks.

A pneumatic radial tire has a thread surface extending along a specific curvature plane which includes a first arc with the radius R1 having a center on the tire's equatorial plane and passing through the tire's equatorial point, a second arc with the radius R2 having a center on the tire's equatorial plane and intersecting with the first arc at an intersection distant from the tire's equatorial plane by 0.2 to 0.25 times the tire width SW, and a third arc with the radius R3 passing through a ground contact outer edge point of the ground contact surface, when a standard load is applied, and a belt intermediate height point on the tread surface. In the specific curvature plane, the curvature radius ratio R2/R3 is set in a range from 4 to 12, and the curvature radius ratio R1/R2 is set in a range from 2.6 to 4.6 when the aspect ratio H/SW is 0.55 or less. The tread surface is provided with a main circumferential groove, preferably having a groove width of 0.06 to 0.10 times the tire width SW, extending near the intersection of the first arc and the second arc in the tire circumferential direction for dividing the tread surface into the crown part and an outer shoulder part. Narrow lateral grooves crossing the tire circumferential direction divide the crown part and shoulder part into blocks.

Stability pneumatic radial tire with high cornering and steering

An apparatus for determining the shape of contact patch and the contact pressure of a tire comprises a contact member made of a transparent material, a pressing unit for pressing the outer peripheral surface of the tire against the contact member, a sheet having elastic projections arranged regularly on one surface thereof and uniformly distributed thereover, and an observation device for observing through the contact member the projections as deformed when the tire is pressed against the contact member with the sheet interposed therebetween and with the projections thereof facing the contact member. The shape of contact patch and contact pressure of the tire can be determined by observing deformed projections by the device.

Apparatus for determining shape of contact patch and contact pressure of

An apparatus and method in which light from source is kept within a transparent moving roadway and a tire tread is pressed onto one surface of the roadway. The ground contact patch of the tire is observed from the opposite side, and the ground contact area and the non-ground contact area of the tire tread is distinguished clearly. The dynamic behaviour of the ground contact patch of the rotating tire roadway can be observed by means of a camera unit. The information obtained can be utilized for tire design to improve tire performance.

Apparatus and method for observing the ground contact patch of a tire

A pneumatic safety tire in which each sidewall portion is provided with a minimum thickness at a position E between an outer edge point A and a 65% height point B both located on each side of the tire equator, where the outer edge points A are defined as the axially outer edges of a ground contacting region on the tread surface in a standard loaded state in which the tire mounted on a regular rim and inflated to a regular pressure is loaded with a regular load, and the 65% height points B are defined as the positions at 65% height of the tire section height H from the bead base in a standard unloaded state in which the tire mounted on the regular rim and inflated to the regular pressure is kept free of load, and further the thickness of each sidewall portion is gradually increased from the minimum thickness position E toward the 65% height point B.

Pneumatic safety tire

A pneumatic tire having tread blocks provided in the side walls with grooves opened at the top of the block, the depth gW of each groove in the axial direction of the tire being in the range of 5 to 50% of the block width BW, the width gL of each groove in the circumferential direction being in the range of 5 to 25% of the block length BL, the height gH of each groove at the block side wall being in the range of 15 to 80% of the depth GH of a main groove dividing the block, whereby performances on the snowy and icy roads and noise generation and wear resistance on the normal roads are well improved in good balance.

Growing community of inventors

Kobe, Japan

Akira Kajikawa