Sumitomo Rubber Industries Limited

Tsuneyuki Nakagawa

Kiyoshi Ueyoko

Kazuki Numata

Kazumi Yamazaki

Minoru Nishi

Tomoyasu Shibata

Shinichi Miyazaki

Masaki Shiraishi

Yoshihide Kojima

Hiroyuki Noma

Mikio Takatsu

Shuichi Sakamoto

Yasuyoshi Mizukoshi

Kenji Asano

In a pneumatic tire, a cord spacing between an axially outer cord layer and an axially inner cord layer such as: a turnup portion and a main portion of a carcass ply; or a bead reinforcing cord layer and a carcass ply turnup portion, is increased from the radially inside to the outside of the tire to improve the durability of the bead portion.

Pneumatic tire

A pneumatic tire comprises a pair of bead portions each provided therein with a bead core made of windings of at least one wire, a carcass ply of cords extending between the bead portions and turned up around the bead core from the axially inside to the outside of the tire to form a pair of turnup portions and a main portion therebetween, a rubber bead apex disposed radially outside the bead core and between each said turnup portion and the main portion, and a fiber reinforced rubber spacer interposed between the bead core and the carcass ply to provide a positive distance between the carcass ply cords and bead core wire. The fiber reinforced rubber spacer has a securing portion which extends radially outwardly and axially outwardly from the axially inside of the bead core while separating from the bead core but contacting with the rubber bead apex. A distance (L , L ) between an outermost point of the securing portion and the bead core is in a range of from to times a height of the bead core.

A heavy duty radial tire has a carcass including a carcass ply made of cords arranged at an inclination angle of 70 to 90 degrees with respect to the tire equator, the carcass ply including a main portion extending from a tread portion to a bead core in a bead portion and integrally provided with a turnup portion turned up from the axially inside to the outside at the bead core, a bead apex disposed between the main portion and turnup portion of the carcass ply, wherein the turnup portion extends radially outwardly along the axially outer surface of the bead apex and has a portion extending substantially parallel with and adjacent to the carcass ply main portion from the radially outer end of the bead apex, and the length L of the parallel portion is 1.0 to 8.0 times the maximum section width CW of the bead core.

Heavy load radial tire with specified carcass turnup

A pneumatic tire comprises a breaker disposed radially outside a carcass and having a cord angle of not less than 10 degrees, and a band disposed between the carcass and the breaker and having a cord angle of less than 10 degrees, the breaker having a double-layered cord structure comprising a radially outer layer and a radially inner layer between which the cord inclination is reversed, the band being made of spiral windings of at least one cord; and the breaker is preferably formed by continuously winding at least one cord zigzag around the radially outside of the band plural times, in each turn the tape being bent at the axial edges of the breaker.

Pneumatic tire with band between carcass and breaker

A heavy duty radial tire is to be mounted on a 15 degree drop center rim. In a mounted state that the tire is mounted on the rim and inflated to 0.5 ksc but not loaded, the inside diameter BC of the bead cores at the radially innermost point thereof is set to being not more than the diameter BT at the heel point of the bead portions. In a demounted state that the tire is demounted from a rim, the bead bottom is tapered towards the axial inside of the tire at an angle .theta. of from 1.0 to 1.9 times the angle .alpha. of the tapered bead seat of the rim. In the mounted state, the bead core has a radially inner surface tapered at the substantially same angle as the bead seat, and the axial distance BP of the axially inner end of this tapered inner surface from the bead heel point is set in the range of from 1.3 to 2.1 times the maximum width BW of the bead core measured in the direction parallel to the bead seat. A straight line drawn between a point P2 at which the carcass main portion starts to contact the bead core and a point P3 at which the carcass main portion and a radially extending straight line passing the axially inner end of the radially inner surface of the bead core intersect each other, is inclined at angle .beta. of from 45 to 60 degrees with respect to the tire axial direction.

Heavy duty radial tire with specified bead core inside diameter

This invention relates to high-speed radial tires, and more particularly to radial tires wherein the thickness ratio (Gc-Gs)/Gc, that is the ratio of the difference between the crown tread thickness Gc, which is a thickness of the tread on the equator of the tire, and the shoulder tread thickness Gs, which is a thickness of the tread of the ground contact surface at the outer edge in direction of the tire axis, to the crown tread thickness Gc is set to be 0 or more and 0.8 or less. By setting the ratio within a range of 0 to 0.8, the force Fs acting in the radial direction on the tread shoulder part, out of the total load acting to the tire, is decreased, thus, the deformation in the bead part is diminished and the permanence in the bead part can be improved. In a tire having the ratio of 0 to 0.8, by setting the angle of the belt cords to be 0 to 20 degrees, it can be used for aircraft and by setting the angle of the belt cords to be 20 to 40 degrees and the aspect ratio to be 60% or less, it can be used for high-speed passenger cars.

High speed radial tire with durable bead part

A heavy duty radial tire and rim assembly exhibiting improved bead durability, wherein the bottom face of the bead is composed of an axially inner face Si and an axially outer face So each tapered axially inward to decrease the diameter of the bottom face, the taper in the inner face Si is greater than that of the outer face So, the boundary between the inner face Si and the outer face So is located axially inward of the center of gravity of the bead core, and in the condition that the tire is mounted on a regular rim and inflated to a regular pressure, the axial distance X of the axially inner edge Q2 of the bead core from a bead heal Q1 defined as an intersection between a rim base line B and an extending line of the inner surface of a rim flange of the rim is not less than 80% and not more than 105% of the height HR of the radially outer edge Q3 of the rim flange from the rim base line; and the radial distance Y of the radially outer edge Q4 of the bead core measured radially inwardly from the radially outer edge Q3 of the rim flange is not less than 0% and not more than 30% of the height HR of the rim flange from the rim base line.

Growing community of inventors

Shirakawa, Japan

Tsuneyuki Nakagawa