Sumitomo Rubber Industries Limited

Kenji Tagashira

Yoshiaki Uemura

Masanao Yoshida

Akio Yamamoto

Fumikazu Yamashita

Mitsushige Idei

Shinichi Matsuura

Tetsuhiko Yoshioka

Masanori Omoteda

Pneumatic tire for passenger cars having specified harshness factor

A run-flat tire comprises a tread portion, a pair of bead portions, a pair of sidewall portions, a carcass comprising at least one carcass ply extending between the bead portions, a belt disposed radially outside the carcass in the tread portion, and a tread reinforcing layer disposed between carcass plies or alternatively between the carcass and belt, the tread reinforcing layer made of a high elastic modulus rubber compound having a complex elastic modulus E* of from 10 to 30 MPa, a thickness t of from 0.8 to 2.5 mm, and an axial width WA of 0.7 to 1.0 times the tread width TW of the tire.

Run-flat tire with tread reinforcing layer

A pneumatic tire which is improved in uneven tread wear resistance without sacrificing the on-the-snow/ice running performance. The tread portion comprises a plurality of blocks, each provided with at least two sipes. Each sipe extends axially of the tire at an angle of from 90 to 88 degrees to the circumferential direction of the tire. In a cross section of the block parallel to the tire equatorial plane, each sipe extends radially inwardly from the radially outer surface of the block at an angle (.beta.) of from 2 to 10 degrees with respect to the tire radial direction so that the radially inner ends of the sipes inclining the same direction towards the rear surface of the block. The rear surface of the block inclines to the same direction as the sipes at an angle (.gamma.2) of not more than 30 degrees with respect to the tire radial direction but not less than the angles (.beta.) of the sipes. The front surface of the block inclines to the reverse direction to the rear surface.

Pneumatic tire with sipes

A tire and rim combination including a flanged rim and a pneumatic tire. The tire includes a pair of bead parts each provided with a plurality of, preferably at least 8, pieces of exhaust ribs projecting from a bead outside surface and extending outwardly in a radial direction so as to form air passages for escape of air between a rim flange and the bead outside surface during rim assembly. A distance F1 from an inner end of the exhaust rib to a bead base line is in a range of 0.7 to 1.5 times a flange height FH measured from the bead base line, and a distance F2 from an outer end of the exhaust rib to the bead base line is not less than 1.1 times the flange height FH. The exhaust rib has a triangular sectional shape having a width of 0.5 to 1.0 mm and a height of 0.5 to 2.0 mm.

Tire and rim combination with exhaust ribs in tire bead

A pneumatic tire to be mounted on a normal rim, has a pair of bead parts each having a bead bottom surface seating on a rim seat of the normal rim and bead outside surface connecting with the bead bottom surface and abutting against a rim flange of the normal rim. The bead outside surface is provided with an exhaust extending outward in the radial direction from an inner end of the exhaust so as to form the air passage for escape of air between the rim flange and bead outside surface at the time of rim assembly. The inner end of the exhaust is positioned within a region remote from a bead base line by a distance of 0.5 to 1.5 times a separating point height Fh defined as a height in the radial direction from the bead base line to a separating point at which the bead outside surface separates from the rim flange.

Tire and rim combination with exhaust means in tire bead

The invention is directed to a pneumatic tire that can be mounted on a rim (wheel) to assure good engagement with the rim while preventing the occurrence of rim offsets. The bead portion 4a (as indicated by a solid line in FIG. 1) on the front side of a tire 1 which is later mounted on the rim has a bead base diameter .phi..sub.1, a toe portion angle .phi..sub.1, a contact angle .alpha..sub.1 , and a heel portion radius R.sub.1, whereas the bead portion 4b (as indicated by a dashed line in FIG. 1) on the back side of the tire which is first mounted on the rim has a bead base diameter .phi..sub.2, a toe portion angle .theta..sub.2, a contact angle .alpha..sub.2 and a heel portion radius R.sub.2. The bead portion 4a on the front side has a different shape than the bead portion 4b on the back side and the following two relationships hold between the two bead portions; the angle of .theta..sub.2 of the toe portion on the back side should be greater than the angle .theta..sub.1 of the toe portion on the front side, with the difference between the two angles being not more than 4.degree. (4.degree..gtoreq..theta..sub.2 -.theta..sub.1 &gt;0.degree.); and the bead base diameter .phi..sub.2 on the back side should be greater than the bead base diameter .phi..sub.1 on the front side (.phi..sub.2 &gt;.phi..sub.1); preferably, the difference between the bead base diameters on the two sides (.phi..sub.2 -.phi..sub.1) is 2 mm or less (.phi..sub.2 -.phi..sub.1 .ltoreq.2 mm).

Pneumatic tire with differently shaped bead portions

A pneumatic tire to be mounted on a normal rim, has a pair of bead parts each having a bead bottom surface seating on a rim seat of the normal rim and bead outside surface connecting with the bead bottom surface and abutting against a rim flange of the normal rim. The bead outside surface is provided with exhaust extending outward in the radial direction from an inner end of the exhaust so as to form the air passage for escape of air between the rim flange and bead outside surface at the time of rim assembly. The inner end of the exhaust is positioned within a region remote from a bead base line by a distance of 0.5 to 1.5 times a separating point height Fh defined as a height in the radial direction from the bead base line to a separating point at which the bead outside surface separates from the rim flange.

Pneumatic tire

A tubeless radial tire for heavy duty use which comprises a pair of symmetrically shaped bead cores disposed one in each of the bead portions, a radial carcass having cords extending between the bead portions and turned up around the bead cores, and a belt layer disposed radially outside the carcass and inside a tread, wherein in each bead portion, the carcass is provided with a profile such that the inclination thereof at a point (P) located at the same axial position as the geometric center of the bead core is 45 to 53 degrees with respect to the axial direction of the tire when the tire is mounted on a regular rim and inflated to a pressure of 0.5 kgf/sq.cm.

Growing community of inventors

Kobe, Japan

Kenji Tagashira