# US 2014/0150942 A1 · Tire comprising a tread with a foamed material

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- Number: US 2014/0150942 A1
- Document ID: US20140150942A1
- Status: Published application
- Kind: A1
- Application number: 14/114,520
- Filed: 2012-04-24
- Published: 2014-06-05
- Earliest claimed: 2011-04-28
- Assignees: Compagnie Generale Des Etablissements Michelin
- Inventors: José Merino Lopez; Didier Vasseur
- Web page: https://patentgrep.com/patent/US20140150942A1

## CPC

- B60C 11/032: {Patterns comprising isolated recesses}
- B29D 30/0662: {Accessories, details or auxiliary operations}
- B60C 11/005: {with cap and base layers}
- B60C 11/14: Anti-skid inserts, e.g. vulcanised into the tread band
- B60C 2011/147: {Foamed rubber or sponge rubber on the tread band}
- B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)

## Abstract

The tyre comprises a tread (14) that has a running layer (14A) made of cellular material having a thickness E and a degree of expansion of greater than or equal to 50%. The running layer (14A) comprises hollow tread pattern elements (20, 22, 26). At least 95% of the hollow tread pattern elements (20, 22, 26) each satisfy the following two conditions a) and b): a) the tread pattern element (20, 22, 26) is separated from at least one other hollow tread pattern element (20, 22, 26) by a distance less than or equal to DP=7 mm, the separation distance between two hollow tread pattern elements (20, 22, 26) being the shortest distance between these two tread pattern elements (20, 22, 26) travelled in the cellular material, b) the tread pattern element (20, 22, 26) has a depth at least equal to 80% of the thickness E of the running layer (14A).

## Claims

### Claim 1

A tire of the type comprising a tread that has a running layer made of a cellular material having
a thickness E, and
a degree of expansion of greater than or equal to 50%,
the running layer comprising hollow tread pattern elements, wherein at least 95% of the hollow tread pattern elements each satisfy the following two conditions a) and b):
a) the tread pattern element is separated from at least one other hollow tread pattern element by a separation distance less than or equal to DP=7 mm, the separation distance between two hollow tread pattern elements being the shortest distance between these two tread pattern elements travelled in the cellular material,
b) the tread pattern element has a depth at least equal to 80% of the thickness E of the running layer.

### Claim 2 (depends on 1)

The tire according to claim 1, in which DP=6 mm.

### Claim 3 (depends on 1, 2)

The tire according to claim 1 or 2, in which the hollow tread pattern elements satisfying the conditions a) and b) form elements chosen from:
water evacuation channels that delimit, in the running layer, blocks of cellular material, and
blind holes made in these blocks so as to open radially.

### Claim 4 (depends on 1)

A process for manufacturing a tire, in which an uncured blank of the tire is vulcanized in a mold, wherein, the tire that it is desired to manufacture being according to claim 1, comprising:
providing the uncured blank with a mass of material, comprising a pore-forming agent, intended to form the running layer made of cellular material, and
placing the uncured blank in a vulcanization mold comprising molding elements for molding the hollow tread pattern elements,
wherein the mold is such that at least 95% of the molding elements each satisfy the following condition:
the molding element is separated from at least one other molding element by a distance less than or equal to DM=7 mm, the separation distance between two molding elements being the shortest distance between these two molding elements travelled between these molding elements.

### Claim 5 (depends on 4)

The process according to claim 4, in which DM=6 mm.

### Claim 6 (depends on 4, 5)

The process according to claim 4 or 5, in which the pore-forming agent comprises p,p′-oxybis(benzenesulphonyl hydrazide).