Sumitomo Rubber Industries Limited

Honda Giken Kogyo Kabushiki Kaisha

Masatoshi Tanaka

Takaaki Ishida

Yurie Tanami

Masaki Shiraishi

Ryuhei Sanae

Takuya Yamamoto

Kiichiro Kakumu

Yasuhiro Kubota

Hiroyuki Nakagawa

Sawa Ogihara

Shoichi Kuwahata

Tatsuya Sasaki

Sumio Takatsu

Yoshiichiro Iwahashi

Shigeaki Suzuki

Ken Miyazawa

Kazuyuki Kohara

A run-flat tire is provided at its side wall with a side reinforcing rubber layer having a substantially falcate cross section, and a side reinforcing cord layers extending inside and outside along a ply body of a carcass in a radial direction. A radially outer end of the side reinforcing cord layer is sandwiched and terminated between a belt layer and a ply body of the carcass. A radial inner end of the side reinforcing cord layer is terminated in the vicinity of the bead core.

Run-flat tire with side reinforcing cord layer

A tire profile () includes a tread (), a shoulder (), a flat portion (), an upper sidewall () and a lower sidewall (). The shoulder () is provided in contact with a tread () at a point (Pa). The flat portion () is provided in contact with the shoulder () at a point (Pb). The upper sidewall () is provided in contact with the flat portion () at a point (Pc). A system including an input portion and a calculating portion is used for designing the profile (). When the numeric values of a radius of curvature (R) of the shoulder () and an inclination angle (&#x3b8;) of the flat portion () are input by the input portion, the calculating portion calculates a length (L) of the flat portion () and a radius of curvature (R) of the upper sidewall (). Based on the input numeric values and the calculated numeric values, the profile () is drawn by CAD software.

Tire profile designing method

Typical numeric data for specifying a shape of a first product having a typical size are stored in a storage portion. By an input portion (), a size of a second product other than the typical size is input. A calculating portion () determines recommended numeric data for specifying a shape of the second product based on the size of the second product and the typical numeric data. By the input portion (), furthermore, corrected numeric data for the recommended numeric data are input. The calculating portion () decides the validity of the corrected numeric data. In the case in which the corrected numeric data have the validity, the calculating portion () determines final numeric data for specifying the shape of the second product based on the recommended numeric data and the corrected numeric data. Based on the final numeric data, the shape of the second product is drawn by CAD software.

Method, program and system for designing shape of product, such as a tire

First of all, size data (MD), (BD), (BH) and (MW) of a tire are input. Next, a ratio (b/a) of a major axis radius (b) to a minor axis radius (a) of an ellipse () is input. Then, constants (S), (a) and (b) of an involute function are calculated. Based on the involute function having these constants, a profile function () from a central position in a lateral direction to a maximum width position is determined over an X-Y plane. Subsequently, the profile curve () is divided into a large number of segments. Next, each of the segments is caused to approximate to a circular arc. In the approximation, a radius of curvature is determined in such a manner that the adjacent circular arcs are tangent to each other. Thus, a profile is designed.

Tire profile design method

A runflat tire system comprising a pneumatic tire, a wheel rim and a support ring disposed in a tire cavity is disclosed, wherein the wheel rim comprises a pair of axially spaced bead seats, and a support-ring seat between the bead seats; the support ring has an inner circumferential surface fitting to the above-mentioned support-ring seat, and an outer circumferential surface contacting with the inside of a tread portion of the tire mounted on the wheel rim when the tire is deflated; and one of or alternatively each of the support-ring seat and the inner circumferential surface is provided with an ordered uneven surface which can reduce a friction in the axial direction between the inner circumferential surface and the support-ring seat, while maintaining or increasing the friction in the circumferential direction.

Runflat system

A runflat tire system comprises a pneumatic tire, a wheel rim on which the pneumatic tire is mounted, and a support ring made of an elastic material and disposed in a cavity surrounded by an inner surface of the rim and an inner surface of the tire mounted thereon, wherein the support ring comprises an annular body extending in a circumferential direction of the tire and being provided with a plurality of recesses each opening at the cavity, and at least two sound reflectors each being attached to the recess and including an outer surface made of a non-porous material so as to reflect sound in the cavity.

Runflat tire system and support ring therefor

A runflat tire system comprises a pneumatic tire, a wheel rim on which the pneumatic tire is mounted, and a support ring made of elastic material and disposed in a cavity surrounded by an inner surface of the rim and an inner surface of the tire mounted thereon, wherein the support ring comprises an annular body extending in a circumferential direction of the tire and provided with a plurality of hollows opening at the cavity, and at least one noise damper made of sponge material having apparent density of 0.1 g/cmor less and disposed in the hollow such that the noise damper does not protrude into the cavity from an inlet surface of the hollow.

A support ring for a runflat tire system which comprises an annular body made of an elastic material having a radially inner circumferential surface which fits to a mounting portion of a wheel rim when mounted thereon, and a radially outer circumferential surface which comes into contact with the inside of the tread portion of a pneumatic tire mounted on the wheel rim when the tire is deflated and loaded, wherein the outer circumferential surface is wider in the axial width than the inner circumferential surface, and in a cross section including the central axis of the support ring, the outline of the annular body is substantially a trapezoidal shape of which two parallel long and short sides are the outer and inner circumferential surfaces, respectively, and the remaining two sides are inclined at acute angles with respect to the long side.

A runflat tire system which comprises a wheel rim, a pneumatic tire and a support ring is disclosed. The support ring comprises a radially inner annular portion, a radially outer annular portion, and a supporting wall extending from the inner annular portion to the outer annular portion, wherein the supporting wall comprises a main wall extending continuously in the circumferential direction in a trapezoidal waveform, and axial walls extending axially outwardly from the main wall.

A pneumatic tire comprises a tread portion, a pair of sidewall portions, a pair of bead portions, a carcass extending between the bead portions, and a tread reinforcement disposed radially outside the carcass in the tread portion. The tread reinforcement comprises a reinforcing rubber layer and a radially outer reinforcing cord layer. The radially outer reinforcing cord layer is made of cords disposed radially outside the reinforcing rubber layer. The reinforcing rubber layer extends across the substantially overall tread width and made of a rubber material having a hardness of not less than 70 degrees and a loss tangent of not more than 0.15. In a tire meridian section, the thickness of the reinforcing rubber layer being in a range of not less than 2 mm at the tire equator and gradually decreasing towards the axial edges of the reinforcing rubber layer.

Run-flat tire with tread reinforcing rubber layer

A pneumatic tire, more particularly a run flat tire, comprises at least three radial carcass plies each extending between bead portions through a tread portion and sidewall portions, the tread portion is provided between the radially outermost carcass ply and radially inner next carcass ply with a crown reinforcing rubber layer so that at least two carcass plies are disposed radially inside the crown reinforcing rubber layer, and each of the sidewall portions is provided between the axially innermost carcass ply and axially outer next carcass ply with a side reinforcing rubber layer so that at least two carcass plies are disposed axially outside the side reinforcing rubber layer. The reinforcing rubber layers are preferably made of a low heat generation rubber having a complex elastic modulus of 8 to 15 Mpa, and a loss tangent of 0.03 to 0.08. The complex elastic modulus of the side reinforcing rubber layer is preferably less than that of the crown reinforcing rubber layer.

Pneumatic tire with crown reinforcing rubber layer and side reinforcing

A pneumatic tire comprises a radially inner bead core disposed in at least one of the bead portions, a radially outer bead core disposed radially outside the inner bead core, a buffer rubber layer disposed between the radially inner bead core and radially outer bead core to provide a predetermined space therebetween, and a toroidal carcass extending between the bead portions through the tread portion and sidewall portions, wherein the carcass comprises a ply of cords turned up around the radially outer bead core to be secured thereto, passing between the radially outer bead core and the buffer rubber layer, so that a radially outward tension of the carcass caused by tire inflation acts less on the radially inner bead core than the radially outer bead core.

Pneumatic tire with radially inner and radially outer bead core

A pneumatic tire has a tread part with two circumferential grooves continuously extending in the circumferential direction in either side of the tire's equator so as to divide the tread part into a pair of shoulder parts and a central part. The central part has a surface utilizing successive convex curves composed of a pair of inner groove walls, which extend inside in the axial direction of tire along a curve convexed outwardly in the radial direction from inner bottom edges of the circumferential grooves, and a central ground-contact surface, which is smoothly connected between the pair of the inner groove walls. The central ground-contact surface is substantially in contact with a virtual tread line connected between outer surfaces of the shoulder parts.

Pneumatic tire including two grooves and two rubber parts

A pneumatic tire having a tread portion with a convex profile, a pair of axially spaced bead portions, and sidewall portions extending therebetween. The tread portion is provided with a pair of circumferentially extending continuous grooves defining groove edges with a combined width of more than 16% of the ground contacting width. The tire design reduces overall tire noise, especially air resonance without deteriorating tire performance on wet surfaces.

Pneumatic tire

A pneumatic tire has a tread part with two wide circumferential grooves having a width GW of 35 mm or more and extending in either side of the tire's equator so as to divide the tread part into a pair of shoulder parts and a central part. The central part has a surface utilizing successive convex curves of a pair of inner groove walls and a central ground-contacting surface. When the tire is mounted on a regular rim, inflated with regular internal pressure and applied with normal load, widths SW1, SW2 of shoulder ground-contacting areas Fs1, Fs2 where the shoulder parts contact with the ground are different to each other.

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Kobe, Japan

Masatoshi Tanaka