Tire tread

Patent metadata

Field	Value
Publication number	US-9969222-B2
Application number	US-201113821409-A
Country	US
Kind code	B2
Filing date	Sep 8, 2011
Priority date	Sep 10, 2010
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

The invention relates to an asymmetric tread for a tire comprising a plurality of basic patterns, for each of which there is defined a sipes density corresponding to
∑ i ⁢ li P * Wm
where i is the number of sipes in the pattern, li is the length of the i th sipe on the tread surface, P is the pitch of the basic pattern and Wm is the width of the basic pattern, a sipes orientation level corresponding to

∑ i ⁢  li * α ⁢ ⁢ i  P * Wm ,
where αi is the positive or negative angle formed on the tread surface by the i th sipe with the transverse direction and |αi|≤45 degrees and a steering pull criterion for the basic pattern corresponding to

 ∑ i ⁢ li * α ⁢ ⁢ i ∑ i ⁢  li * α ⁢ ⁢ i   .
The sipes density is greater than or equal to 60 μm/mm 2 , the sipes orientation level is greater than or equal to 1.5 degrees/mm and the steering pull criterion for the pattern is less than or equal to 0.2. The tread comprises an inboard half-tread adjacent to an inboard sidewall of the tire, the sipes orientation level relating to the inboard half-tread being greater than 2 degrees/mm.

First claim

The invention claimed is:

1. An asymmetric tread for a tire adapted to be fitted to a motor vehicle in a predetermined direction of fitting, comprising:
a tread surface adapted to be in contact with a roadway when the tire is being driven, and comprising an in-board half tread adjacent to an inboard sidewall of the tire and an outboard half-tread adjacent to an outboard sidewall of the tire;
a sequence of basic patterns arranged in the circumferential direction (X), each basic pattern extending over at least 80% of the width (W) of the tread;
each basic pattern comprising a plurality of raised elements provided with sipes opening onto the tread surface, each sipe having a width less than 1 mm and a depth of at least 3 mm;
wherein:

the following are defined for each basic pattern:
a sipes density (D) corresponding to

∑
i

⁢
li

P
*
Wm

where i is the number of sipes in the pattern, li is the length of the i th sipe on the tread surface, P is the pitch of the basic pattern and Wm is the width of the basic pattern;
a sipes orientation level (NO) corresponding to

∑
i

⁢



li
*
α
⁢

⁢
i



P
*
Wm

,

where αi is the positive or negative angle formed on the tread surface by the i th sipe with the transverse direction and |αi|≤45 degrees;
a steering pull criterion for the basic pattern (CT) corresponding to



∑
i

⁢

li
*
α
⁢

⁢
i

∑
i

⁢



li
*
α
⁢

⁢
i





wherein the sipes density (D) is greater than or equal to 60 μm/mm 2 , the sipes orientation level (NO) is greater than or equal to 1.5 degrees/mm, and the steering pull criterion (CT) is less than or equal to 0.2, and
wherein the sipes orientation level (NO) of the inboard half-tread is greater than 2 degrees/mm, such that the sipes of the inboard half-tread are inclined more steeply with respect to the transverse direction than the sipes of the outboard half-tread.

2. The asymmetric tread according to claim 1 , wherein the steering pull criterion (CT) is less than 0.1.

3. The asymmetric tread according to claim 1 , wherein the steering pull criterion (CT) is less than 0.05.

Assignees

• Fugier Sebastien
• Jamot Nicolas
• Fraenkel Bertrand
• Michelin & Cie
• Michelin Rech Tech

Inventors

• Fugier Sébastien
• Jamot Nicolas
• Fraenkel Bertrand

Classifications

• B60C2011/129

  Sipe density, i.e. the distance between the sipes within the pattern · CPC title

• B60C2011/1209

  straight at the tread surface · CPC title

• B60C11/12

  characterised by the use of narrow slits or incisions, e.g. sipes · CPC title

• B60C11/11

  in which the raised area of the pattern consists only of isolated elements, e.g. blocks (B60C11/12, B60C11/13 take precedence) · CPC title

• B60C11/0304 Primary

  Asymmetric patterns · CPC title