Sumitomo Rubber Industries Limited

Other

Sri Sports Limited

Kiyoto Maruoka

Kuniyasu Horiuchi

Yoshikazu Yabuki

Akihiro Nakahara

Kazuo Hochi

Minoru Nishi

Kazuhisa Fushihara

Masaya Tsunoda

Hideaki Yoshikawa

Atsushi Yamahira

Keiji Moriyama

Masatoshi Yokota

Kengo Oka

Hidenori Hiraoka

Satoshi Tsuda

Jun Nishibayashi

Kaichiro Wayaku

Noritoshi Nakagawa

Mikio Yamada

Akihiko Hamada

Tetsuo Yamaguchi

Katsumi Terakawa

Kaname Yamada

Hiroyuki Onimatsu

Seigou Sakagami

Yoshimasa Koizumi

Masanori Takahashi

Norio Hayashi

Yasuo Mitarai

Yutaka Yoshida

Satoshi Ito

Satoshi Mano

Naoki Kato

Katsutoshi Kitaoh

Takahiro Kimishima

Hiroyuki Tsujinaka

Masatoshi Takahashi

Kinuko Tsujinaka, Legal Representative

Minoru Tsujinaka, Legal Representative

Hiroyuki Tsujinaka, Deceased

Tsuyoshi Ito

Yasuhisa Sekiguchi

Seigo Sakagami

Hiroshi Yoshinaga

A pneumatic tire includes a tread, a carcass and a belt. The belt includes inner and outer layers including steel cords and topping rubbers such that the cords in each layer are parallel-aligned and inclined with respect to equatorial plane and inclination directions of the cords in the layers are opposite to each other with respect to the plane, inclination angle &#x3b1;s of the cords in the inner layer at edge is larger than inclination angle &#x3b1;c at the plane, the edge of the inner layer is at position of 0.9 times axial direction width, inclination angle &#x3b2;s of the cords in the outer layer at edge is larger than inclination angle &#x3b2;c o at the plane, the edge of the outer layer is at position of 0.9 times axial direction width, and difference between the angles &#x3b1;s and &#x3b1;c is larger than difference between the angles &#x3b2;s and &#x3b2;c.

Pneumatic tire

To accurately measure a tread radius of a rotating tire. A method for measuring a tread radius has a tread radius measuring process which comprises a measurement step, an averaging step, and a calculation step. In the measurement step, the radial distances from three laser displacement meters to the tread surface of the rotating tire are measured to obtain radial distance data yyywhose number is m per the entire circumference of the tire. In the averaging step, an averaged value yN, yN, yN is obtained by averaging the remaining radial distance data from which noise data have been removed by performing a smoothing process on the number m of the radial distance data yyyIn the calculation step, a tread radius TR is calculated from the averaged values yN, yN, yN and the distances xxxof the laser displacement meters in the axial direction of the tire.

Method for measuring tread radius of tire, and device for measuring tread radius used therefor

A heavy duty radial tire comprises a tread portion divided into four or five circumferential ribs and a tread reinforcing belt including a maximum width belt ply. The width Bw of the maximum width belt ply is 0.90 to 0.98 times the tread width Tw. The contour shape of the tire footprint has a ground contacting length CB at a 70% width position and a ground contacting length CC at a 97% width position, wherein the ratio CB/CC is 1.00 to 1.06. In a tread edge near region J, (1) the axially outermost shoulder rib is provided with no circumferential groove having a width of less than 5 mm, and a ratio Rs/Rc of an axial width Rs of the shoulder rib to an axial width Rc of a center rib is 1.25 to 1.45, or (2) the shoulder rib is provided with a narrow circumferential groove having a width of less than 5 mm to divide the shoulder rib into an axially inner main portion and an axially outer narrow portion, and a ratio Rs/Rc of an axial width Rsof the axially inner main portion to an axial width Rc of a center rib is 1.25 to 1.45.

Heavy duty radial tire

A heavy duty tire comprises: a bead filler disposed radially outside a bead core and axially outside a carcass main portion; a bead-reinforcing layer made of steel cords; and a chafer made of a rubber extending along the bead bottom surface. The chafer rubber has a complex elastic modulus in a range of 8 to 12 MPa and a 100% modulus in a range of 4.0 to 5.5 MPa. In the bead-reinforcing layer, the steel cord count is 25 to 40/5 cm, the steel cord diameter is 0.8 to 1.2 mm, and the cord angle is 30 to 60 degrees with respect to the tire radial direction. The bead filler comprises a main filler made of a low modulus rubber and a fastening filler made of a high modulus rubber. The fastening filler has an L-shaped cross sectional shape and comprises an axially-extending base portion and a radially-extending axially inner portion. The main filler has a part wedged between the base portion and axially inner portion of the fastening filler.

Heavy duty tire

A heavy duty tire comprises a belt disposed radially outside a carcass. The belt consists of a innermost first ply, a second ply and a outermost third belt ply. With respect to the tire equator, the cords of the first ply are laid at an angle &#x3b8;of 15 to 25 degrees; the cords of the second ply are laid at an angle &#x3b8;of 15 to 25 degrees; the cords of the third ply are laid at an angle &#x3b8;of 45 to 60 degrees; the cords of the second ply are inclined oppositely to the cords of the first ply; the cords of the third ply are inclined to the same direction as the cords of the second ply; |&#x3b8;| is not more than 5 degrees; |&#x3b8;| is 30 to 45 degrees; the axial widths W, Wand Wof the first, second and third belt plies, respectively, satisfy W&#x3e;W&#x3e;W; strengths S, Sand Sof the first, second and third belt plies, respectively, satisfy S&#x3e;S&#x3e;Sand 1.0&#x3e;S/S&#x3e;=0.6.

A heavy-load radial tire includes a bead apex rubbercomposed of a high-elastic lower apex portionand a low-elastic upper apex portion. The lower apex portionhas an L-shaped cross section composed of a bottom piece portiondisposed along the radially outer surface of a bead coreand a standing piece portionstanding from the axially inner end of the bottom piece portionand radially outwardly extending along a ply main portionof a carcass. At an outer end position Pof a ply turnup portion, the upper apex portionhas a thickness Tof 0.50 to 0.75 times a core width Bw of the bead core. At an outer end position Pof an outer wound-up portionof a bead reinforcing cord layer, the upper apex portionhas a thickness Tof 0.57 to 0.90 times the core width Bw. The core width Bw is 0.68 to 0.80 times a bead bottom width BL. A distance Woriented in parallel to an outer surfaceS of the bead coreand ranging from a bead heal point Ph to an axially innermost endof the bead coreis 0.92 to 1.08 times the bead bottom width BL.

Heavy-load radial tire

A heavy-load tire has a wind bead structure in which a turned-up portion of a carcass ply is wound around a bead core, in which a bead portion is equipped with a bead reinforcing layer having a u-shaped cross section and a bead apex rubber having a triangular-shaped cross section. The turned-up portion has an auxiliary turned-up portion passing through the vicinity of a radially outer side of the bead core. The bead apex rubber includes a high complex elasticity modulus inner apex portion disposed at a radially inner side and a low complex elasticity modulus outer apex portion disposed at a radially outer side.

Heavy-load tire with wind bead structure

A heavy-duty pneumatic tire includes a carcass ply turned up around a bead core in each bead portion from the inside to the outside of the tire so as to have a pair of turnup portions and a main portion therebetween; and a bead apex and an L-shaped reinforcing cord layer. The bead apex includes: an L-shaped high-modulus inner bead apex including a base part and a radial part; and a delta-shaped low-modulus outer bead apex disposed on the radially outside of the base part of the L-shaped inner bead apex and on the axially outside of the radial part of the L-shaped inner bead apex. The L-shaped reinforcing cord layer is made up of an radially inner part extending on the radially inner side of the bead core, and an radially outer part extending along the axially outer surface of the carcass ply turnup portion.

Heavy-duty pneumatic tire with L-shaped inner bead apex

A heavy-load tire has a wind bead structure in which a turned-up portion of a carcass ply is wound around a bead core, in which a bead portion is equipped with a bead reinforcing layer having a U-shaped cross section and a bead apex rubber having a triangular-shaped cross section. The turned-up portion has an auxiliary turned-up portion passing through the vicinity of a radially outer side of the bead core. The bead apex rubber includes a high complex elasticity modulus inner apex portion disposed at a radially inner side and a low complex elasticity modulus outer apex portion disposed at a radially outer side.

A heavy duty tire comprises: a carcass ply of cords extending between bead portions; and a bead reinforcing layer disposed in each of the bead portion. The carcass ply has edges winded around the bead cores so that the winded portion has a base part extending along the bead core from the axially inside to the axially outside thereof, and a radially outer part extending axially inwards on the radially outside of the bead core. The bead reinforcing layer comprises: a curved portion extending along the base part; an axially outer portion extending radially outwardly, separation from the base part; and an axially inner portion extending radially outwardly along a main portion of the carcass ply. The bead reinforcing layer is composed of a ply of cords laid side by side, and the spacing Da of the cords in an axially outer part beneath the bead core, of the curved portion is not less than 1.5 times and not more than 3.0 times the spacing Db of the cords in the axially outer portion.

A heavy duty tire comprises a bead filler disposed in each bead portion (). The bead filler () comprises: a main layer () having a complex elastic modulus E*of from 2.0 to 6.0 Mpa; and a fastening layer () having a complex elastic modulus E*of from 20 to 70 Mpa. The fastening layer comprises a base portion (B) and an axially inner portion (A) to have a L-shaped cross section. The height Ha of the axially inner portion (A) is 35 to 100 mm and not more than the height Hb of the main layer (), and the radial height Hb is 40 to 100 mm, each from the bead base line. The thickness of the axially inner portion (A) gradually decreases towards the radially outside so that, when measured along a straight line Xdrawn perpendicularly to the axially outer surface of the bead filler from a point Pthereon at a distance of 25 mm radially outward from the bead base line: the thickness Tb from the axially outer surface of the bead filler to the interface between the axially inner portion (A) and the main layer is 7.0 to 13.0 mm; the thickness Ta from the interface to the axially inner surface of the axially inner portion (A) is 1.0 to 4.0 mm; and the ratio Ta/Tb is 0.1 to 0.35.

A pneumatic tirehaving improved uniformity and durability and including a toroidal carcassextending from a tread portionto each of bead coresin bead portionsthrough sidewall portions, a belt layerdisposed radially outward of the carcassin the tread portion, and a cushion rubberhaving an approximately triangular cross section disposed between the carcassand each of axial edge portionsE of the belt layer, and a method for producing the same, wherein the cushion rubberis made from a strip laminated body formed by circumferentially and spirally winding a first ribbon-like unvulcanized rubber strip and a second ribbon-like unvulcanized rubber strip having a different composition from that of the first rubber strip.

Pneumatic tire with cushion rubber and method for producing the same

A heavy duty tire having an improved durability in bead portions and comprising a carcass ply of steel cords, the end portions of which are turned up around bead cores from the axially inside to the axially outside of the tire, and a core protecting rubber having a complex elastic modulus of 50 to 80 Mpa, at least a part of which is located in a core inside region which is located axially inward of the bead core and is sandwiched between the axially inner surface of the bead core and the steel cords of the turnup portion of the carcass ply.

A heavy duty tire has a tread portionwhich is divided into five inner, intermediate and outer rib-like land portions R, R, R, Rand R. The inner rib-like land portion Ris virtudally divided into half regions Rand Ron each side of a tire equator. The intermediate rib-like land portions Rand Rare virtually divided into tire equator-side half regions Rand R, and into ground-contact edge-side half regions Rand R. In a regular ground-contact state in which a normal load is applied, when total sums of ground-contact load applied to the half regions R, R, R, Rand Rare defined as P, P, P, Pand P

Heavy duty tire with tread portion having three longitudinal main grooves

The present invention relates to a heavy duty tire being capable of preventing positional shift of carcass cords in the blowout direction while restricting rupture of the carcass cords for improving bead durability. A ply turnup portionsof a carcassincludes a sub-portionthat extends proximate of an upper surface SU of a bead corein a tire radial direction upon inclining towards a ply main body portionand further includes an auxiliary cord layerfor pressing the sub-portion outside thereof in the radial direction. A bead portionis further provided with a U-shaped bead reinforcing layer. A periphery of the bead coreis coated by a reinforcing rubber layermade of high elastic rubber having a complex elastic modulus E*a of 20 to 70 MPa, and a rubber thickness Tof a clearance portion G at which bead wiresand carcass cordsare adjacent is defined to be not less than 0.7 mm while a cushion rubber layermade of low elastic rubber layeris interposed between the reinforcing rubber layerand the carcass cords

Growing community of inventors

Kobe, Japan

Kiyoto Maruoka