PASSENGER-VEHICLE PNEUMATIC RADIAL TIRE

• US 20170197466A1
• Filed: 05/28/2015
• Published: 07/13/2017
• Est. Priority Date: 05/30/2014
• Status: Abandoned Application

• Current Assignee: Bridgestone Corporation
• Original Assignee: Bridgestone Corporation
• Inventors: HATANAKA, Shintaro, KUWAYAMA, Isao
• Application Number:
  US15/314,732
• Publication Number:
  US 20170197466A1
• Time in Patent Office: Days
• CPC Class Codes: B60C 11/04 in which the raised area of the pattern consists only of continuous circumferential ribs, e.g. zig-zag B60C11/12, B60C11/13 take precedence
• CPC Class Codes: B60C 11/1236 with special arrangements in the tread pattern
• CPC Class Codes: B60C 17/0009 comprising sidewall rubber inserts, e.g. crescent shaped inserts
• CPC Class Codes: B60C 2011/0025 Modulus or tan delta
• CPC Class Codes: B60C 2017/0054 Physical properties or dimensions of the inserts
• CPC Class Codes: B60C 2200/04 for road vehicles, e.g. passenger cars
• CPC Class Codes: B60C 3/04 characterised by the relative dimensions of the section, e.g. low profile B60C3/06 takes precedence
• CPC Class Codes: Y02T 10/86 Optimisation of rolling resistance, e.g. weight reduction

Abstract

When the tire is assembled to a rim and filled with an internal pressure of 250 kPa or more, an SW/OD ratio of the tire is 0.26 or less if the tire has a sectional width SW of less than 165 (mm), whereas a sectional width SW and an outer diameter OD (mm) of the tire satisfy a relation of 2.135×SW+282.3≦OD if the tire has a sectional width SW of 165 (mm) or more, the tread rubber has a dynamic storage modulus E′ at 30° C. of 6.0 MPa to 12.0 MPa and a loss tangent tan δ at 60° C. of 0.05 to 0.15, and when a tread surface is equally divided into four regions in a tire width direction, a shoulder circumferential sipe extending in a tire circumferential direction is disposed in the shoulder portion.

Claims

1. A passenger-vehicle pneumatic radial tire comprising:

a carcass consisting of one or more carcass plies of radially arranged cords toroidally extending between a pair of bead portions; and

a tread rubber disposed on a tire radial outer side of the carcass, wherein

when the tire is assembled to a rim and filled with an internal pressure of 250 kPa or more,

an SW/OD ratio of a sectional width SW to an outer diameter OD (mm) of the tire is 0.26 or less if the tire has the sectional width SW of less than 165 (mm), whereas

the sectional width SW and the outer diameter OD (mm) of the tire satisfy a relation of 2.135×

SW+282.3≦

OD if the tire has the sectional width SW of 165 (mm) or more,

the tread rubber has a dynamic storage modulus E′

at 30°

C. of 6.0 MPa to 12.0 MPa and a loss tangent tan δ

at 60°

C. of 0.05 to 0.15, and

when a tread surface is equally divided into four regions in a tire width direction, and two regions on a tire widthwise inner side are each referred to as a center portion and two regions on a tire widthwise outer side are each referred to as a shoulder portion, a shoulder circumferential sipe extending in a tire circumferential direction is disposed in the shoulder portion.

2. The passenger-vehicle pneumatic radial tire according to claim 1, wherein, when the shoulder portion is equally divided into three regions in the tire width direction, the shoulder circumferential sipe is disposed in a center region of the three regions of the shoulder portion.

3. The passenger-vehicle pneumatic radial tire according to claim 1 or 2, wherein the shoulder circumferential sipe has a depth is from the tread surface of 4 mm or more.

4. The passenger-vehicle pneumatic radial tire according to claim 1 or 2, wherein a total length of the shoulder circumferential sipe in one of the shoulder portions, measured over an entire circumference of the tire along the tire circumferential direction, is 50% or more of a length of the tire, measured over the entire circumference of the tire along the tire circumferential direction at a tire widthwise position, where the shoulder circumferential sipe is disposed.

5. The passenger-vehicle pneumatic radial tire according to claim 4, wherein a total length of the shoulder circumferential sipe in one of the shoulder portions, measured over an entire circumference of the tire along the tire circumferential direction, is 80% to 100% of a length of the tire, measured over the entire circumference of the tire along the tire circumferential direction at a tire widthwise position, where the shoulder circumferential sipe is disposed.

6. The passenger-vehicle pneumatic radial tire according to claim 1 or 2, wherein

at least two circumferential main grooves continuously extending in the tire circumferential direction are provided in the tread surface,

a center land portion defined by the two circumferential main grooves is formed in the center portion, and

when the center land portion is equally divided into three regions in the tire width direction, two or less rows of center circumferential sipes with a depth tc from a tread surface of 3 mm or less are disposed in a center region of the three regions of the center land portion.

7. The passenger-vehicle pneumatic radial tire according to claim 6, wherein

two of the center circumferential sipes are continuously extending side by side in the tire circumferential direction in the center land portion, and

a width w₁ of the center land portion in the tire width direction and a width w₂ of a land portion in the tire width direction located between two of the center circumferential sipes satisfy a relation of:

√

(2tc)<

w₂<

w₁/4.

8. A passenger-vehicle pneumatic radial tire comprising:

a carcass consisting of one or more carcass plies of radially arranged cords toroidally extending between a pair of bead portions; and

a tread rubber disposed on a tire radial outer side of the carcass, wherein

when the tire is assembled to a rim and filled with an internal pressure of 250 kPa or more,

an SW/OD ratio of a sectional width SW to an outer diameter OD (mm) of the tire is 0.26 or less if the tire has the sectional width SW of less than 165 (mm), whereas

the sectional width SW and the outer diameter OD (mm) of the tire satisfy a relation of 2.135×

SW+282.3≦

OD if the tire has the sectional width SW of 165 (mm) or more,

the tread rubber has a dynamic storage modulus E′

at 30°

C. of 6.0 MPa to 12.0 MPa and a loss tangent tan δ

at 60°

C. of 0.05 to 0.15, and

when a tread surface is equally divided into four regions in a tire width direction, and two regions on a tire widthwise inner side are each referred to as a center portion and two regions on a tire widthwise outer side are each referred to as a shoulder portion,

at least two circumferential main grooves continuously extending in a tire circumferential direction are disposed on the tread surface,

a center land portion defined by two of the circumferential main grooves is formed in the center portion, and

when the center land portion is equally divided into three regions in the tire width direction, a second center circumferential sipe is disposed in a center region of the three regions of the center land portion.