Sumitomo Rubber Industries Limited

Mikio Takatsu

Kiyoshi Ueyoko

Shinichi Miyazaki

Hideaki Yoshikawa

Hiroshi Hoshino

Masayoshi Nishitani

Yoshihide Kojima

Hiroyuki Noma

Tsuneyuki Nakagawa

Haruyuki Sano

Takao Otani

Toshiaki Yamamoto

Yasusuke Yonekawa

A radial tire having a carcass extending from a tread through sidewalls to a bead core in each of two bead parts and turned up around the bead cores. The tire includes a belt layer disposed on the outside of the tire in the tire radial direction of the carcass in the tread portion and a cut breaker disposed between the carcass and the belt layer. Each carcass ply has cords that are buried in topping rubber and arranged independently in parallel to each other within the same plane without linking wefts. In a region from the bead bottom to the turned up end of the carcass, the distance between cords in adjacent carcass plies is within a range of 1/4 to 2 times a diameter K1 of the carcass cord.

Radial tire with enhanced bead durability

A pneumatic tire for high speed and heavy duty use, in which durability of the bead and lower sidewall region is improved. The tire includes: a carcass comprising a radial ply of cords turned up around bead cores from the axially inside to the outside, the carcass cords rubberized with a topping rubber having a 100% modulus of 40 to 70 kg/cm.sup.2, an elongation at rupture of 200 to 350%, and a stress at rupture of 150 to 300 kg/cm.sup.2 ; a rubber bead apex disposed between the carcass main portion and each turned up portion; a buffer cord layer interposed between the carcass main portion and each turned up portion, the buffer cord layer extending radially inwardly to the bead portion to form an axially inner portion and then turned up around the bead core to form an axially outer portion, the axially inner portion having a radially outer edge located radially outward of the radially outer edge of the carcass turned up portion and radially inward of the maximum tire section width point, the axially outer portion having a radially outer edge located radially inward of the middle height position of the bead apex; in a normal pressure condition, at least 60%, in number, of the spacings of reinforcing cords existing in a tire side portion defined between two points (P1 and P2) are in the range of 0.25 to 2.0 times the thickness (D) of the carcass cords, the reinforcing cords including the carcass cords and the buffer cords.

High speed heavy duty tire and rim assembly whose tire includes a buffer

A heavy duty high speed cross ply tire has a carcass composed of at least one aromatic polyamide fiber cord ply, the product T.sqroot.D of the cable twist number T (turns/10 cm) of the belt cord and the square root of the total denier number D (deniers) of the cord is 2.466.times.10.sup.3 to 3.036.times.10.sup.3 and the elongation E (%) at breakage of the belt cord divided by the total denier number D is 7.78.times.10.sup.-4 to 12.22.times.10.sup.-4.

High speed heavy duty cross ply tire

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 high speed radial tire has a carcass and a belt layer, wherein; in the state of inflated with a standard internal pressure on a standard rim, a equator height H1 defined as a height of crossing point at which the inner surface of the belt layer intersects the surface of the tire equator is larger than an outer end height H2 defined as a height of the outermost end of the inner surface of the belt layer. Furthermore, a belt camber quantity H defined as a difference between the height H1 and the height H2 is set at 6% or more of the belt width W.

High-speed radial tire for heavy load with specified belt camber quantity

A high speed heavy duty tire with improved bead durability, which includes: a bead core disposed in each of the bead portions; a radial carcass extending between the bead portions and turned up around the bead cores to form two turned up portions and one main portion therebetween; a belt disposed radially outside the carcass; a tapered bead apex disposed between the main portion and each turned up portion of the carcass and extending radially outwardly; and a sidewall disposed on each side of the carcass and extending from the bead base to the tread edge, wherein the sidewall comprises a lower sidewall and an upper sidewall, the lower sidewall extending radially outwardly from the bead base over a height corresponding to the radially outermost edge of a flange of the tire's regular rim, and the upper sidewall extending radially outwardly from the radially outer edge of the lower sidewall. Each bead portion is provided between the carcass and the lower sidewall with a side packing of small thickness, the side packing is made of rubber having a 100% modulus MP of 53 to 95 kg/sq.cm., the bead apex is made of rubber having a 100% modulus MA of 78 to 120 kg/sq.cm., the lower sidewall is made of rubber having a 100% modulus MC of 40 to 70 kg/sq.cm., the upper sidewall is made of rubber having a 100% modulus MS of 10 to 45 kgf/sq.cm., and these 100% modulus values MP, MA, MC and MS are in the relation of MS&lt;MC&lt;MP&lt;MA.

High speed heavy duty tire including bead part with side packing rubber

A heavy duty high speed radial tire has a belt composed of at least one aromatic polyamide fiber cord ply, the product T.multidot..sqroot.D of the cable twist number T (turns/10 cm) of the belt cord and the square root of the total denier number D (deniers) of the cord is 2.466.times.10.sup.3 to 3.036.times.10.sup.3, and the elongation E (%) at breakage of the belt cord divided by the total denier number D is 7.78.times.10.sup.-4 to 12.22.times.10.sup.-4.

Heavy duty high speed radial tire with aromatic polyamide belt cords

A high speed tire for heavy duty vehicles comprise a belt layer of a carcass with radial structure, wherein a profile of the outer circumference of the tire in the specified internal pressure state satisfies that the maximum width and radius ratio Ro/W is not more than 0.54. At this point, the ratio Ro/W is defined as the ratio of the radius Ro of curvature of the arc which passes through maximum width point C, a reference point Q and an intermediate height point M to tire maximum width W. The maximum width point C is defined as a point where the tire width is maximum W. The reference point Q is defined as a point which is apart from the bead bottom line by the length of 0.2 times the total sectional height H of the tire. And the intermediate height point M is defined as a point which is intermediate between the maximum width point C and the reference point Q.

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Takarazuka, Japan

Mikio Takatsu