Sumitomo Rubber Industries Limited

Seiji Nomura

Wako Iwamura

Makoto Sugiya

An airless tire includes a tread ring, a hub positioned on radially inner side of the ring, and a spoke structure including polymer material and connecting the ring and hub, the structure including spoke pieces arrayed in circumferential direction. Each spoke piece has a tread connecting portion, a hub connecting portion, and a spoke curved portion between the tread and hub connecting portions, each spoke piece has straight radial length LSb of at least 1.05 times straight radial length LSa and curved radial length LLb of at least 1.03 times LSb when positioned at 0&#xb0; on coordinate around the tire axis where a perpendicular line extending vertically upward from the tire axis is set 0&#xb0;, LSb is measured along the base line under base-load condition, LSa is measured along the base line under no-load condition, and LLb is measured along a curve of each spoke piece under the base-load condition.

Airless tire

A pneumatic tire () includes a tread portion () having at least one heat-dissipating recess portion (). The recess portion () includes an opening edge () and an inner wall portion (). The opening edge () includes a linear first edge () and second edge () opposite each other. The inner wall portion () includes a first wall surface () extending from the first edge () to a bottom portion () at the deepest position of the recess portion (), and a second wall surface () extending from the second edge () to the bottom portion (). An inclination angle ([theta]) of the first wall surface () with respect to a first normal () to a contact surface passing the first edge () is greater than an inclination angle ([theta]) of a second wall surface () with respect to a second normal () to the contact surface passing the second edge ().

Pneumatic tire

A pneumatic tire is provided with an asymmetric tread pattern which comprises an inboard shoulder longitudinal groove (A) at an axial distance Xi from the tire equator (C) and an outboard shoulder longitudinal groove (B) at an axial distance Xo from the tire equator (C). The distances Xi and Xo are 27 to 33% of the tread width (TW), and the axial distance Xi is less than the axial distance Xo. A tread crown region between the inboard edge (Ao) of the inboard shoulder longitudinal groove (A) and the outboard edge (Bo) of the outboard shoulder longitudinal groove (B) has a sea ratio of 30 to 50%.

A pneumatic tire comprises buttress parts each provided with a row of protrusions arranged circumferentially of the tire. The protrusion has a radially outside wall surface rising from the surface of the buttress part, a radially inside wall surface rising from the surface of the buttress part, and a top surface extending between the radially inside wall surface and the radially outside wall surface. The radially outside wall surface starts to rise from the surface of the buttress part at a certain distance from the tread edge so that the minimum radial distance Kmin from the tread edge to the protrusions is in a range of from 5 to 15 mm.

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Kobe, Japan

Seiji Nomura