Bridgestone Corporation

Isao Kuwayama

Shintaro Hatanaka

Hiroyuki Matsumoto

Kentaro Kozuki

Yasuo Himuro

Jun Watanabe

Shintaro Hayashi

Kohei Hasegawa

Takayuki Fukunaga

Takahiro Tahira

Shingo Hiura

Takuto Kawashima

A pneumatic radial tire for passenger vehicles of the present disclosure includes a carcass toroidally spanning between a pair of bead portions and including plies of radially arranged cords. A sectional width SW (mm) and an outer diameter OD (mm) of the tire satisfy a predetermined relational expression. At least one noise reducer is provided on an inner surface of the tire. The noise reducer is provided at least in the center region and the shoulder region. Among thicknesses of the noise reducer measured in a direction perpendicular to the inner surface of the tire, a maximum thickness Ts in the shoulder regions is larger than a maximum thickness Tc in the center region.

Pneumatic radial tire for passenger vehicles

A pneumatic tire comprising a carcass, at least one inclined belt layerhaving a cord extending inclined at an angle of 30&#xb0; or more relative to the tire circumferential direction, and a treadarranged outward in the tire radial direction of the inclined belt layer, wherein a circumferential cord layerarranged inward in the tire radial direction of the treadhas a high-rigidity region and a low-rigidity region and the high-rigidity region has a higher negative ratio in a ground contact width of the treadthan the low-rigidity region.

Pneumatic tire

A pneumatic tire comprising a carcass, at least one inclined belt layer, at least one first circumferential cord layerarranged inward in the tire radial direction of the inclined belt layer, a treadarranged outward in the tire radial direction of the inclined belt layer, and a second circumferential cord layerwhich is arranged outward in the tire radial direction so as to cover a tire width direction end of the inclined belt layer, and where X is defined as X=Y&#xd7;n&#xd7;m&#xd7;d, Y is the Young's modulus (GPa) of the cord, n is the number of cords implanted (cords/50 mm), d is the cord diameter (mm), and m is the number of the first circumferential cord layers, X is smaller than X of the first circumferential cord layer

A pneumatic tire comprising a carcass, at least one inclined belt layerhaving a cord extending inclined at an angle of 30&#xb0; or more relative to the tire circumferential direction, and a treadarranged outward in the tire radial direction of the inclined belt layer, wherein a circumferential cord layerarranged inward in the tire radial direction of the treadhas a high-rigidity region and a low-rigidity region and the high-rigidity region has a lower negative ratio in a ground contact width of the treadthan the low-rigidity region.

A passenger vehicle pneumatic tire comprising: a carcass; and inclined belt layers and a circumferential belt layer, wherein: the inclined belt layers include at least two inclined belt layers having different tire widthwise widths; an inclination angle &#x3b8;with respect to the tire circumferential direction of the cords forming the inclined belt layer having the widest width and an inclination angle &#x3b8;with respect to the tire circumferential direction of the cords forming the inclined belt layer having the narrowest width satisfy correlations that 30&#xb0;&#x2264;&#x3b8;&#x2264;85&#xb0;, 10&#xb0;&#x2264;&#x3b8;&#x2264;30&#xb0;, and &#x3b8;&#x3e;&#x3b8;; and a tire widthwise width Wof the inclined belt layer having the widest width and a tire widthwise width Wof the inclined belt layer having the narrowest width satisfy a correlation that W&#x2264;0.6W.

Tire

A pneumatic tire comprises, in a tread surface: at least two circumferential main grooves continuously extending in a tire circumferential direction; and at least one rib-like land portion each defined by two adjacent circumferential main grooves from among the at least two circumferential main grooves. The rib-like land portion has: a circumferential sipe including a circumferential sipe portion extending in the tire circumferential direction; and a both-end closed sipe having both ends terminating within the rib-like land portion. When a land portion width of the rib-like land portion is evenly divided by three where a region at a center in a tire width direction is a center region and regions on both sides of the center region in the tire width direction are side regions, the circumferential sipe portion is located only in the center region, and the both-end closed sipe is located in any of the side regions.

A tire comprising: a carcass; and inclined belt layers and a circumferential belt layer, wherein: the circumferential belt layer satisfies a correlation that X&#x2265;750 when it is defined that X=Y&#xd7;n&#xd7;m, where Y is a Young's modulus in GPa of the cords forming the circumferential belt layer, n is a number of the cords implanted per 50 mm of width, and m is a number of layers of the circumferential belt layer; the inclined belt layers comprise at least two inclined belt layers having different tire widthwise widths; and a tire widthwise width Wof an inclined belt layer having a widest width and a tire widthwise width Wof an inclined belt layer having a narrowest width satisfy a correlation that W&#x2264;0.6W.

When a tire is attached to a rim and set to an internal pressure of 250 kPa or more, a ratio SW/OD of the tire is 0.26 or less in the case where SW of the tire is less than 165 (mm), and SW and OD satisfy a relationship 2.135&#xd7;SW+282.3&#x2264;OD in the case where SW is 165 (mm) or more. The tread rubber has dynamic storage modulus E' of 6.0 MPa to 12.0 MPa, and loss tangent tan &#x3b4; of 0.05 to 0.15. In at least one land portion, sipes are arranged with a predetermined pitch length L, and a land portion width W, a tire widthwise sipe component total length Ws of the sipes, the pitch length L, and a tire circumferential sipe component total length Ls of the sipes satisfy relationships 0.4W&#x2264;Ws&#x2264;1.2W and 0.6L&#x2264;Ls&#x2264;3L.

Passenger vehicle pneumatic radial tire

A pneumatic radial tire for a passenger vehicle according to the present invention has an appropriate relationship between a tire cross-sectional width SW and a tire outer diameter OD. Also, a method of using the pneumatic radial tire for a passenger vehicle according to the present invention is to use the above radial tire with at least specified internal pressure.

Pneumatic radial tire for a passenger vehicle and method of using the same

To reduce noise while suppressing increase in rolling resistance, without affecting the formation of a carcass line, provided is a pneumatic tirecomprising an inner liner. The thickness of the inner linerat least in part of a side portionis 1.5 mm or more. When the tireis mounted to a rim, and an internal pressure of 250 kPa or more is applied to the tire, in a case where a sectional width SW of the tire is less than 165 mm, a ratio of the sectional width SW to an outer diameter OD of the tire, SW/OD, is 0.26 or less; and in a case where the sectional width SW of the tire is 165 mm or more, the sectional width SW and the outer diameter OD of the tire satisfy a relation expression OD&#x2265;2.135&#xd7;SW+282.3.

The present invention provides: a pneumatic radial tire for a passenger car, the tire having cross sectional width SW and outer diameter OD satisfying a predetermined relationship formula when the tire is assembled with a rim and inflated at internal pressure of at least 250 kPa; a tire-rim assembly formed by assembling bead portions of said tire with the rim; and a method for using a tire, including preparing a pneumatic radial tire for a passenger car in which cross sectional width SW and outer diameter OD of the tire satisfy a predetermined relationship formula, and using the tire at internal pressure of at least 250 kPa.

Pneumatic radial tire for passenger vehicle, method for using the tire, and tire-rim assembly including the tire

A run-flat tire of the present invention is a pneumatic radial tire for passenger vehicles which has a carcass composed of plies of radially arranged cords toroidally extending between a pair of bead portions, and the a W/L ratio of the section width W to the outer diameter L of the tire is 0.25 or less.

An object of the present invention is to adequately control relationship between a cross sectional width SW and an outer diameter OD of a pneumatic radial tire for a passenger vehicle. The tire is further characterized in that, provided that each half portion in the tire width direction of a ground contact surface of the tire is divided in the tire width direction into three equal portions including a tire-width-direction center portion, a tire-width-direction intermediate portion and a tire-width-direction outer portion from the tire-width-direction center side, rigidity in the tire circumferential direction of the belt reinforcing layer in a region in the tire width direction thereof corresponding to the tire-width-direction outer side portion is lower than rigidity in the tire circumferential direction of the belt reinforcing layer in a region in the tire width direction thereof corresponding to the tire-width-direction center portion.

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Kodaira, Japan

Isao Kuwayama