# US 2014/0150940 A1 · Tire with tread having variable sipe density and round crown

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- Number: US 2014/0150940 A1
- Document ID: US20140150940A1
- Status: Published application
- Kind: A1
- Application number: 14/235,256
- Filed: 2011-07-27
- Published: 2014-06-05
- Earliest claimed: 2011-07-27
- Assignees: Michelin Recherche et Technique S.A.; Compagnie Generale Des Etablissements Michelin
- Inventors: Cyril Guichon; Olivier Piffard; Hobart Ronald Thompson
- Web page: https://patentgrep.com/patent/US20140150940A1

## CPC

- B60C 11/12: characterised by the use of narrow slits or incisions, e.g. sipes
- B60C 11/005: {with cap and base layers}
- B60C 11/0083: {characterised by the curvature of the tyre tread}
- B60C 11/0332: {by the footprint-ground contacting area of the tyre tread}
- B60C 9/2009: {comprising plies of different materials}
- B60C 2009/2022: {comprising cords at an angle of 60 to 90 degrees to the circumferential direction}
- B60C 2009/2051: {Modulus of the ply}
- B60C 2011/0025: {Modulus or tan delta}
- B60C 2011/1295: {variable}
- B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES

## Abstract

This invention relates generally to tires having treads that have a configuration and/or properties for maintaining hydroplaning performance, dry braking performance and improved wear resistance, and, more specifically, to a tire that has a tread that N has a variable sipe density, i.e a higher sipe density in its central portion and a lower sipe density in its shoulder portions, as well as a round crown with a predetermined inflated profile droop. Another embodiment of the present invention further includes the addition of a member that provides more structural stiffness across the crown of a tire, such that better compromises between hydroplaning, dry braking, and wear performances can be obtained.

## Claims

### Claim 1

An apparatus that comprises a tread for use with a tire defining lateral and longitudinal directions, said tread having central and shoulder portions and tread elements with sipes that are located in its central and shoulder regions, wherein:
the distance from one sipe to an adjacent sipe in a tread element found in the center region is in the range of 5-9 mm;
the distance from one sipe to an adjacent sipe in a tread element found in a shoulder region is in the range of 15-35 mm; and
the inflated profile droop is in the range of 5-9 mm as measured from the center of the tread to an edge of the rolling tread width.

### Claim 2 (depends on 1)

The apparatus of claim 1 which further comprises a profiled undertread having at least 1 mm thickness reduction from the shoulder region of the undertread to the center region of the undertread and a modulus increase of at least three tones that of the tread rubber.

### Claim 3 (depends on 2)

The apparatus of claim 2 which further comprises a first, second and third breaking belts wherein the angle of the cords of the third belt are posed at an angle of at least 60 degrees with respect to the longitudinal direction of the tire, said third belt having a modulus in compression of at least 30,000 MPa and having a width that ranges from being as wide as the second belt to being 45 mm less in width as the second belt, said third ply also being laid radially outward of the second belt.

### Claim 4 (depends on 1)

The apparatus of claim 1 wherein said tread is used with a 205/55R16 sized tire.

### Claim 5 (depends on 1)

The apparatus of claim 1 wherein said tread is used with a 245/45R17 sized tire.

### Claim 6 (depends on 4)

The apparatus of claim 4 wherein the Grown radius of said tread is 650 mm when inflated.

### Claim 7 (depends on 5)

The apparatus of claim 5 wherein the crown radius of said tread is 450 mm when inflated.

### Claim 8 (depends on 2)

The apparatus of claim 2 wherein the thickness reduction from the shoulder region of the undertread to the shoulder is at least 2 mm and the modulus increase is at least four times that of the tread rubber.

### Claim 9 (depends on 3)

The apparatus of claim 3 wherein the angle at which the cords are posed from the longitudinal direction of the tire ranges from 65 to 90 degrees.

### Claim 10 (depends on 3)

The apparatus of claim 3 wherein the cords of the third belt comprise a composite reinforcement made from glass and resin.

### Claim 11 (depends on 3)

The apparatus of claim 3 wherein the width of the third belt is 30 mm less than the width of the second belt.

### Claim 12 (depends on 1)

The apparatus of claim 1 wherein the distance from one site to an adjacent sipe in a tread element found in the center region of the tread is 6 mm and the distance from one sipe to an adjacent sine in a tread element found in the shoulder region of the tread is 20 mm.

### Claim 13 (depends on 1)

The apparatus of claim 1, wherein the tread elements are blocks.