Bridgestone Corporation

Bridgestone Tire Company Limited

Hiroyuki Koseki

Yoshihide Kohno

Yasuhiko Kobayashi

Kuninobu Kadota

Hiroyuki Iida

Yoichi Okamoto

Toshiya Miyazono

Kiyoshi Sato

Makoto Tsuruta

Takashi Kukimoto

Tatsuro Shimada

Jun Watanabe

Hidemitsu Nakagawa

Yoshinobu Shoyama

Yasuo Ohsawa

Kiyohito Kawasaki

Kenji Toyoda

Shigehisa Sano

Tamotsu Matsunuma

Norinaga Matsushita

Michitaka Sato

Yumi Kawame

Mana Minomura

Isao Seto

Nanako Takano

A tire component used in a pneumatic radial tire is a rubber-coated layer comprised of a given number of reinforcing elements separately arranged in parallel with each other, in which the reinforcing elements corresponding to at least 30% of all reinforcing elements included in the rubber-coated layer are divided into plural groups, and a distance between mutually adjoining and opposite reinforcing elements not grouped with each other is wider than a distance between mutually adjoining reinforcing elements separately arranged at equal spaces in the group. Thus, the occurrence of cracking at cut ends of the reinforcing elements is prevented to improve the tire durability.

Pneumatic radial tires including a tire component containing groups of

A tire component used in a pneumatic radial tire is a rubber-coated layer comprised of a given number of reinforcing elements separately arranged in parallel with each other, in which the reinforcing elements corresponding to at least 30% of all reinforcing elements included in the rubber-coated layer are divided into plural groups, and a distance between mutually adjoining and opposite reinforcing elements not grouped with each other is wider than a distance between mutually adjoining reinforcing elements separately arranged at equal spaces. Thus, the occurrence of cracking at cut ends of the reinforcing elements is prevented to improve the tire durability.

A pneumatic radial tire for heavy duty vehicles comprises a radial carcass, a belt, a belt reinforcing layer and a tread, in which the belt has a particular structure formed by using a rubberized strip containing one or more cords therein, and the belt reinforcing layer comprised of at least one rubberized cord ply in a region corresponding to at least each side region of the tread, and the belt and the belt reinforcing layer satisfy a ratio h/h.sub.0 of not more than 65%. In the tire of the above structure, the occurrence of shoulder wear is controlled together with the avoidance of belt end separation and the durability is improved.

Pneumatic radial tires with zigzag belt and rubberized cord ply belt

A pneumatic tire comprising a pair of beads, and a carcass ply consisting of a main body located axially inside the beads and outer ply portions extending along the main body of the carcass ply axially outside each of the beads. A number of circumferentially spaced recesses are provided in the outer surface of the tire between a radially outer end of each of the outer ply portions and a location corresponding to a maximum width of the tire, and the recesses has a depth equal to 1/10 time to 1/2 time as large as a thickness of those portions of the tire which are provided with the recesses. The inclined angle of a base portion of each of the beads is about 15.degree. relative to the rotary axis of the tire. In the tire, 0.4P.ltoreq.W.ltoreq.0.8P and B.ltoreq.0.06D in which P, B, W and D are a circumferential pitch of the recesses, a minimum distance between the adjacent recesses, a circumferential width of each of the recesses which is obtained by deducting the minimum distance B from the pitch P, and a diameter of a rim base, respectively.

Pneumatic tires with sidewall recesses

A pneumatic tire includes a toroidal carcass anchored by at least a pair of bead cores and a belt having strips. The strip has as reinforcing elements a plurality of zigzag or wave-shaped cords or filaments arranged side by side around a crown of the toroidal carcass. The strip is coated with a high molecular weight material less in modulus of elasticity than the reinforcing elements. Waves of the reinforcing elements of the strips are arranged in width directions of the belt so that ratios of amplitudes to wave lengths of the waves are maximum at side edges of the belt. The ratios are preferably progressively increased toward the side edges of the belt. Ratios of amplitudes to pitches of the waves are 0.005-0.175 and ratios of pitches of the waves to maximum circumferential lengths when filled with a normal inner pressure is less than 0.025.

Pneumatic tire including wave-shaped cords or filaments

A pneumatic tire comprises a radial carcass of at least one carcass ply wound around each of bead cores from inside toward outside to form a turnup portion, an outer ply inclusive of the turnup portion containing cords each having a modulus of elasticity of not less than 2500 kg/mm.sup.2 and a diameter d, and a rubber stiffener arranged at its radially inward portion between the carcass ply and the outer ply. In a bead structure of such a pneumatic tire, the stiffener is divided into an inner stiffener portion and an outer stiffener portion around a specified boundary plane, and each of these stiffener portions is comprised of rubber having a given Shore A hardness, and a volume ratio of the outer stiffener portion in the stiffener is not less than 10%.

Bead structure for pneumatic tire

A heavy duty radial tire includes at least one radial carcass extending from one bead portion to the other bead portion and using inextensible cords and a belt arranged outwardly of the radial carcass for reinforcing a tread of the tire. The tire comprises, during expanding of the tire from 5% to 100% of a normal inner pressure, a first profile portion expanding radially outwardly in a tread zone, a second profile portion depressing axially inwardly of the tire in a radially outer zone of a sidewall from one end of said tread to a tire maximum width position when filled with the normal inner pressure, and a third profile portion expanding axially outwardly of the tire in a radially inner zone of the sidewall from the tire maximum width position when filled with the normal inner pressure to a parting point of the sidewall from the rim, thereby properly distributing strains occurring in the tire in filling with the normal inner pressure.

Heavy duty radial tire carcass profile

A pneumatic radial tire including a carcass layer having cords embedded therein and arranged perpendicular to an equatorial plane of the tire, and a belt layer including at least one belt ply having a large number of cords embedded therein, the cords including one or more filaments. The cords are disposed radially outside of said carcass layer, arranged substantially in parallel to the equatorial plane of the tire and bent in a wavy or zigzag form. At least those of the cords or filaments located at widthwise outermost locations in the parallel belt ply satisfy the following expression:

Pneumatic radial tire including wavy or zigzag belt cords

A pneumatic tire for a passenger car includes a toroidal carcass anchored by a pair of beads and a belt made of laminated strips. The strips have a number of reinforcing elements of cords or filaments surrounding a crown of the toroidal carcass and are coated with a high molecular weight material having a modulus of elasticity less than that of the reinforcing elements. The belt is of a laminated construction of a first layer and a second layer of a single strip. The first layer has wave-shaped reinforcing elements arranged side by side and directing in parallel with an equatorial plane of the tire, while the second layer has reinforcing elements arranged in parallel with each other at angles of 15.degree.-75.degree., preferably 35.degree.-60.degree. with respect to the equatorial plane.

Pneumatic tire for passenger car including wave-shaped belt reinforcing

A pneumatic tire involves a toroidal carcass ply extending between a pair of beads. The carcass ply consists of a main body located axially inside the beads and a pair of outer ply portions each extending along the main body of the carcass ply and on an axially outer side of the bead. A recess is provided on an outer surface of the tire between a radially outer end of each of the outer ply portions of the tire and the tire maximum width location such that a part of the recess is located in a zone surrounded by a curve C--C, a curve D--D, and an E-axis. The curve C--C satisfies d/s=1-0.825.times..sqroot.2.64-(h/s), and the curves C--C, and D--D, the E-axis, d, s, h are defined as follows: a widthwise center line of the main body of the carcass ply being taken as A--A; a curve passing through the radially outer end of the outer ply portion and being parallel with the curve A--A being taken as B--B; an axis lying on the curve B--B and extending from the radially outer end of the outer ply portion toward the location having maximum width being taken as an H-axis; an axis extending from the radially outer end of the outer ply portion toward an interior of the tire in a direction orthogonal to the H-axis being taken as the E-axis; a distance from an origin as measured along the E-axis extending the radially outer end of the outer ply portion toward the interior of the tire in a direction orthogonal to the H-axis being taken as d, the origin being an intersection between the E-axis and the H-axis; a distance from the radially outer end of the outer ply portion to the center line A--A as measured on the F-axis being taken as s; a distance from the origin as measured along the H-axis being taken as h; and the curve D--D being a curve extending between the curves A--A and B--B and being parallel with the center line A--A, while being spaced from the center line A--A by 1/3s.

Pneumatic tires with recesses in the bead region

A pneumatic radial tire with high durable bead portions includes a pair of bead portions, a pair of sidewalls and a tread extending between the sidewalls, and further includes as a body reinforcement a carcass extending between the bead portions and consisting of plies whose cords are radially arranged. At least one ply being turned up about bead cores of the bead portions from inside to outside of the tire to form a turn-up portions. A carcass pass line in radial section of the tire in its self-holding position filled with 5% of a normal inner pressure under no-load condition includes curvature changing areas in a carcass profile curved toward the turned-up portions in the proximities of positions corresponding to a height of turn-up ends of the ply from a rim diameter line to cause compressive stresses in the bead portions near to the turn-up ends of the ply by deformations of the carcass when the normal inner pressure is filled in the tire. With the above arrangement, the durability at the bead portions of the tire is improved to an extent required for prolongation of life time obtained by recapping the tire repeatedly.

Pneumatic radial tire with high durable bead portions

A pneumatic radial tire having at least one carcass ply, distal ends of which are folded back axially outwardly about a pair of bead cores to form respective turn-up portions. A hard rubber sheet is disposed on the outer side of each turn-up portion in such a manner as to partially overlap with the same in a mutually space-apart relationship, and a soft rubber material which is softer than the hard rubber sheet is interposed between the turn-up portion and the hard rubber sheet, thereby reducing the amount of stress and heat ocurring in the vicinity of the end portions of the turn-up portions of the carcass ply.

Pneumatic radial tire

A high durable pneumatic radial tire includes reinforcing belts of at least four cord layers whose cords are arranged in parallel with each other and coated with rubber. These cord layers are laminated about a crowd region of a radial carcass with the cords intersecting with each other over a crown circumference to reinforce a tread of the tire. The cord layers are divided into two groups of positive and negative signs by signs of inclined angles of projections of the cords of the respective cord layers onto an imaginary coordinate plane including a rotating axis of the tire. The cord layers in each of the groups are wider as they are arranged on further radially outer sides. The maximum width of the cord layers of the one group is much narrower than a maximum width of the cord layers of the other group. In this manner, shearing strains caused by load acting upon the tire in rubbers between the cord layers near to side ends of the cord layers in contact with a tread rubber on the reinforcing belts.

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Kodaira, Japan

Hiroyuki Koseki