# US 9,038,682 B2 · Pneumatic tire

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- Number: US 9,038,682 B2
- Document ID: US9038682B2
- Status: Granted
- Kind: B2
- Application number: 14/238,188
- Filed: 2011-08-10
- Published: 2014-11-27
- Granted: 2015-05-26
- Earliest claimed: 2011-08-10
- Assignees: The Yokohama Rubber Co., Ltd.
- Applicants: Daqian Wang
- Inventors: Daqian Wang
- Web page: https://patentgrep.com/patent/US9038682B2

## CPC

- B60C 11/1353: {with special features of the groove bottom}
- B60C 9/0007: {Reinforcements made of metallic elements, e.g. cords, yarns, filaments or fibres made from metal}
- B60C 9/2006: {consisting of steel cord plies only}
- B60C 9/28: characterised by the belt or breaker dimensions or curvature relative to carcass (B60C9/30 takes precedence)
- B60C 11/042: {further characterised by the groove cross-section}
- B60C 11/1307: {with special features of the groove walls}
- B60C 11/1323: {asymmetric}
- B60C 2009/0085: {Tensile strength}
- B60C 2009/2257: {Diameters of the cords; Linear density thereof}
- B60C 2009/2266: {Density of the cords in width direction}
- B60C 2011/0341: {Circumferential grooves}
- B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES

## Abstract

The pneumatic tire 1 includes a belt layer 14 that includes a circumferential reinforcing layer 145 and a pair of cross belts 142, 143. Also, the pneumatic tire 1 includes at least three or more circumferential main grooves 21 to 23 in the tread portion having groove bottoms that are convex in the groove depth direction. Also, the curvature radius RA of the groove bottom of an arbitrary first circumferential main groove 21, 22 and the curvature radius RB of the groove bottom of an arbitrary second circumferential main groove 23 have the relationship RA<RB.

## Claims

### Claim 1

A pneumatic tire that includes a belt layer having a circumferential reinforcing layer and a pair of cross belts, comprising:
at least three or more circumferential main grooves having groove bottoms that are convex in the depth direction in a tread portion, wherein
in a cross-sectional view in the tire meridian direction, of the circumferential main grooves, a circumferential main groove having the circumferential reinforcing layer below the groove is a first circumferential main groove, and another circumferential main groove is a second circumferential main groove not having the circumferential reinforcing layer below the groove, and
the curvature radius RA of the groove bottom of an arbitrary first circumferential main groove and the curvature radius RB of the groove bottom of an arbitrary second circumferential main groove have the relationship RA<RB.

### Claim 2 (depends on 1)

The pneumatic tire according to claim 1, wherein the curvature radius RA of the groove bottom of an arbitrary first circumferential main groove and the curvature radius RB of the groove bottom of an arbitrary second circumferential main groove have the relationship 1.10≦RB/RA≦1.60.

### Claim 3 (depends on 1)

The pneumatic tire according to claim 1, wherein there is a plurality of second circumferential main grooves in a region bounded by the tire equatorial plane, and the curvature radius RB_out of the groove bottom of the second circumferential main groove that is in the outermost side in the tire width direction and the curvature radius RB of the groove bottom of the other second circumferential main grooves have the relationship RB<RB_out.

### Claim 4 (depends on 1)

The pneumatic tire according to claim 1, wherein the belt layer has a plurality of circumferential reinforcing layers laminated on each other, and there is a plurality of first circumferential main grooves in a region bounded by the tire equatorial plane, and at least one of the first circumferential main grooves has the plurality of circumferential reinforcing layers below the groove, and
the curvature radius RA_min of the groove bottom of the first circumferential main groove having the smallest number of circumferential reinforcing layers from among all the first circumferential main grooves and the curvature radius RA of the groove bottom of the other first circumferential main grooves have the relationship RA<RA_min.

### Claim 5 (depends on 1)

The pneumatic tire according to claim 1, wherein the circumferential reinforcing layer is disposed on the inner side in the tire width direction from the left and right edge portions of the cross belt with the narrower width from among the pair of cross belts, and the width W of the narrower cross belt and the distance S from the edge portion of the circumferential reinforcing layer to the edge portion of the narrower cross belt are within the range 0.03≦S/W.

### Claim 6 (depends on 1)

The pneumatic tire according to claim 1, wherein wire from which the circumferential reinforcing layer is made is steel wire, and the circumferential reinforcing layer has not fewer than 17 ends/50 mm and not more than 30 ends/50 mm ends.

### Claim 7 (depends on 1)

The pneumatic tire according to claim 1, wherein the diameter of the wire not less than 1.2 mm and not more than 2.2 mm.

### Claim 8 (depends on 1)

The pneumatic tire according claim 1, wherein the circumferential reinforcing layer is formed by winding a single steel wire in a spiral manner.

### Claim 9 (depends on 1)

The pneumatic tire according to claim 1, wherein the circumferential reinforcing layer is formed by winding a plurality of wires spirally adjacent to one another.

### Claim 10 (depends on 9)

The pneumatic tire according to claim 9, wherein the plurality of wires includes five or fewer wires.

### Claim 11 (depends on 10)

The pneumatic tire according to claim 10, wherein a width of winding per layer of the wires when the wires are would in multiple layers is 12 mm or less.

### Claim 12 (depends on 9)

The pneumatic tire according to claim 9, wherein the plurality of wires are would while inclined with respect to the tire circumferential direction in the range of ±5 degrees.

### Claim 13 (depends on 9)

The pneumatic tire according to claim 9, wherein a wire diameter is in the range of not less than 1.2 mm and not more than 2.2 mm.

### Claim 14 (depends on 13)

The pneumatic tire according to claim 13, wherein the wire diameter is measured as a diameter of a circle circumscribing the plurality of wires.

### Claim 15 (depends on 1)

The pneumatic tire according to claim 1, wherein elongation of belt cords of the circumferential reinforcing layer when subjected to a tensile load of 150 N to 200 N is not less than 2.0% and not more than 3.5%.

### Claim 16 (depends on 1)

The pneumatic tire according to claim 1, wherein:
the curvature radius RA of the groove bottom of an arbitrary first circumferential main groove and the curvature radius RB of the groove bottom of an arbitrary second circumferential main groove have the relationship 1.10≦RB/RA≦1.60; and
there is a plurality of second circumferential main grooves in a region bounded by the tire equatorial plane, and the curvature radius RB_out of the groove bottom of the second circumferential main groove that is in the outermost side in the tire width direction and the curvature radius RB of the groove bottom of the other second circumferential main grooves have the relationship RB<RB_out.

### Claim 17 (depends on 1)

The pneumatic tire according to claim 1, wherein:
the belt layer has a plurality of circumferential reinforcing layers laminated on each other, and there is a plurality of first circumferential main grooves in a region bounded by the tire equatorial plane, and at least one of the first circumferential main grooves has the plurality of circumferential reinforcing layers below the groove, and the curvature radius RA_min of the groove bottom of the first circumferential main groove having the smallest number of circumferential reinforcing layers from among all the first circumferential main grooves and the curvature radius RA of the groove bottom of the other first circumferential main grooves have the relationship RA<RA_min; and
the circumferential reinforcing layer is disposed on the inner side in the tire width direction from the left and right edge portions of the cross belt with the narrower width from among the pair of cross belts, and the width W of the narrower cross belt and the distance S from the edge portion of the circumferential reinforcing layer to the edge portion of the narrower cross belt are within the range 0.03≦S/W.

### Claim 18 (depends on 1)

The pneumatic tire according to claim 1, wherein:
wire from which the circumferential reinforcing layer is made is steel wire, and the circumferential reinforcing layer has not fewer than 17 ends/50 mm and not more than 30 ends/50 mm ends; and
the diameter of the wire not less than 1.2 mm and not more than 2.2 mm.