Bridgestone Tire Company Limited

Bridgestone Corporation

Shinichiro Ohkuni

Hiroyoshi Takigawa

Hiroshi Ogawa

Toshio Hayakawa

Yoichi Kitazawa

Nobuhiro Miyamura

Shinichi Tamada

Hideaki Nishio

Mitsuhisa Yahagi

Iwao Arimura

Makoto Tanaka

A pneumatic belted tire for motorcycle is disclosed, which comprises as a casing reinforcement a carcass composed of at least one ply containing organic fiber cords arranged at 70.degree.-90.degree. with respect to the mid-circumference of the tire and a belt composed of a belt layer containing a cord with a modulus of elasticity of not less than 600 kgf/cm.sup.2 helically arranged at a slightly inclined angle with respect to the mid-circumference of the tire. In the tire of this type, the belt is composed of at least two belt segments parted at the mid-circumference of the tire and having a helically winding arrangement of at least one cord, and has a width corresponding to 0.5-1.1 times of a tread width, wherein the cord directions of these segments are opposite to each other with respect to the mid-circumference.

Pneumatic belted tires for motorcycles

A pneumatic tire for a two-wheeled vehicle, including a pair of sidewalls, a tread, a carcass, bead rings embedded in radially inner ends of the pair of sidewalls and stiffeners including tapered rubber fillers. According to the invention, the tire comprises a belt layer between the tread and the carcass. The belt layer consists of at least one ply whose width is at least 0.5 time of a width of the tread. Cords of the ply have a modulus of elasticity of at least 600 kg/mm.sup.2 and are arranged substantially in parallel with an equatorial plane of the tire. The tire according to the invention maintains a hoop effect of the belt layer to sufficiently exhibit characteristics as a radial tire and eliminates an extreme difference in bending rigidity in radial directions over from the tread to the sidewalls to obtain smooth turning of the two wheeled vehicle at a corner.

Pneumatic tire for two-wheeled vehicle

A pneumatic tire for motorcycles is disclosed, which comprises a tread portion defining a maximum width of the tire, a pair of sidewall portions, a pair of bead portions, a carcass of radial or semi-radial structure composed of at least one rubberized cord ply containing organic fiber cords therein, and a belt superimposed about a crown region of the carcass and composed of at least one cord layer containing cords with a modulus of elasticity of at least 600 kgf/mm.sup.2 arranged at an angle of not more than 30.degree. with respect to the equatorial plane of the tire, and has an aspect ratio of not more than 86%. In this tire, a ratio of a distance between a radial height of the sidewall portion and a position of a maximum width of the carcass to a radial height of the sidewall portion is not more than 20%, and both end portions of at least one rubberized cord layer constituting the carcass are wound around bead rings from inside toward outside to form turnups, and a stiffener inclusive of a tapered rubber filler having a Shore A hardness of at least 60.degree. is disposed from an upper part of bead ring toward the tread portion.

Pneumatic tires for motorcycles

Motorcycle tire

A pneumatic belted tire for use in motorcycles is disclosed, which comprises a toroidal carcass, a tread superimposed about a crown region of the carcass at a width corresponding to the maximum width of the carcass and provided on its surface with a tread pattern, and a belt arranged on the crown region over the width of the tread and composed of plural rubberized layers each containing inextensible cords inclined at an angle of not less than 30.degree. with respect to the equatorial plane. In this type of the tire, the inclination angle of cords in the belt gradually enlarges within a range of 7.degree.-20.degree. from the center of the crown region toward the tread side edge, and the tread is provided on each side edge portion with a substantially continuous rib having a width corresponding to 5-25% of the tread width.

Pneumatic belted tires

A pair of pneumatic belted tires for use in motorcycle are disclosed, each of which comprises a tread extending over a width corresponding to the maximum width of the tire, a pair of sidewalls, a pair of bead portions each containing a bead core therein, a carcass composed of at least one rubberized ply containing organic fiber cords inclined at an angle of 50.degree.-90.degree. with respect to the equatorial plane of the tire, and a belt composed of at least two rubberized plies each containing cords arranged at a certain inclination angle with respect to the equatorial plane. In such a tire pair, an inclination angle .alpha. of cord in the belt for rear wheel tire and an inclination angle .beta. of cord in the belt for front wheel tire satisfy the following relationship:

Pair of pneumatic belted tires for motorcycle

Vehicle tire

A pneumatic tire for heavy load vehicles such as trucks and buses comprising a tread composed of a flat main region and an inclined region located at both side edges of the flat main region and including a number of notches spaced apart from each other and arranged substantially transversely to the circumferential direction of the tire.

Pneumatic tire for heavy load vehicles

A pneumatic tire for a heavy duty vehicle including a tread surface divided along circumferential directions by at least two tread zigzag grooves to form a plurality of circumferential zigzag ribs comprises stress releasing apertures formed at least in zones of the circumferential ribs which are within distances approximately 30% of widths of the circumferential ribs from the side of the ribs to mitigate stress concentrations in corners of the ribs extending in the tread grooves by reducing rigidities of the corners for preventing railway wear which would otherwise occur in the tire of this kind.

Pneumatic tire for a heavy duty vehicle

A radial tire for heavy load vehicles comprising a tread portion having an outer contour composed of a relatively transversely flat main region and a conical region located at both end edges of the main region. A number of thin incisions extend across the conical region having inner ends not reaching to the inside of the main region.

Radial tire for heavy load vehicles

A heavy duty pneumatic radial tire comprises a tread continuous at its round-shaped shoulders with sidewalls and formed with a plurality of main tread grooves extending circumferentially thereof. The tread is formed with a circumferentially extending narrow groove in zigzag in each end zone of contact surfaces of the shoulders with a road surface under a standard load. The zigzag grooves have a width of 15-30% of that of the main tread grooves, an amplitude of 0.5-2.0% of the tread width and a pitch of 2.0-7.0% of the tread width. Each of the shoulders is formed in its side surface with a series of intermittent circumferential caved portions, such that a distance in an axial direction of the tire between the deepest bottoms of the caved portions is 105-110% of the tread width and the deepest bottoms are located in a circle having a diameter less than that of a circle passing through the bottoms of the main tread grooves. With the arrangement, the tire according to the invention does not cause any irregular wear at the shoulders and can reduce and prevent the railway wear and growth thereof toward the center of the tread, so that the wear-resistance of the tire is remarkably improved.

Growing community of inventors

Akishima, Japan

Shinichiro Ohkuni