Tire comprising a carcass reinforcement made up of two layers

Patent metadata

Field	Value
Publication number	US-10654322-B2
Application number	US-201515533849-A
Country	US
Kind code	B2
Filing date	Dec 4, 2015
Priority date	Dec 16, 2014
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

Each of at least two layers of a carcass reinforcement has a breaking force per unit width higher than 2250 daN/dm. The minimum strength per unit width, measured for an elongation of less than 10%, of a second layer of carcass reinforcement is strictly greater than a value equal to 20% of the minimum strength per unit width, measured for an elongation of less than 10%, of a first layer of carcass reinforcement. The reinforcing elements of the two layers of carcass reinforcement have a thread count of less than 750 tex. The elongation of the reinforcing elements of the second layer of carcass reinforcement is greater than 4% under a force of 20 daN, and the secant elastic modulus values under tension at 10% elongation, Mt, Mj, satisfy the relationship Mt/Mj≥1.

First claim

The invention claimed is:

1. A tire with a radial carcass reinforcement and having an inflation pressure of which is greater than or equal to 6 bar, said tire comprising:
a crown reinforcement that is capped radially by a tread, said tread being connected to two beads, each of said beads comprising a bead wire, by two sidewalls, said carcass reinforcement being made up of two layers of textile reinforcing elements, a first layer of carcass reinforcement being turned up around the bead wire in each of the beads, the ends of said first layer of carcass reinforcement being radially on the outside of the radially outermost point of the bead wire in each bead and the second layer of carcass reinforcement extending from one bead to the other without any turnup around the bead wire in each of the beads, its ends being axially on the outside of the axially outermost point of the bead wire in each bead, said tire comprising in each sidewall a first filling element, axially on the inside of the exterior surface of a sidewall and axially on the outside of the turnup of the first layer of carcass reinforcement, and made of a rubber compound having a secant elastic modulus under tension at 10% elongation of Mj, each bead comprising a second filling element made of a rubber compound having a secant elastic modulus under tension at 10% elongation of Mt, extending the bead wire core radially towards the outside, wherein each of the layers of carcass reinforcement has a breaking force per unit width higher than 2250 daN/dm, wherein the minimum strength per unit width, measured for an elongation of less than 10%, of the second layer of carcass reinforcement is strictly greater than a value equal to 20% of the minimum strength per unit width, measured for an elongation of less than 10%, of the first layer of carcass reinforcement, wherein the reinforcing elements of the two layers of carcass reinforcement have a thread count of less than 750 tex, wherein the elongation of the reinforcing elements of the second layer of carcass reinforcement is greater than 4% under a force of 20 daN and wherein the secant elastic modulus values under tension at 10% elongation, Mt, Mj, satisfy the relationship Mt/Mj≥1, and
wherein, in a meridian plane, in each bead, the tire comprises a layer of reinforcing elements made of aromatic polyamide in contact with said first layer of carcass reinforcement over the entire length thereof, at least a part being radially on the inside of the bead wire and of which the ends are radially on the outside of the geometric center of the bead wire and wherein said first layer of carcass reinforcement is interposed between the bead wire and the layer of reinforcing elements made of aromatic polyamide.

2. The tire according to claim 1 , wherein, in a meridean plane, a single layer of reinforcing elements is present axially between the exterior surface of the tire and the turnup of the first layer of carcass reinforcement in a zone delimited radially towards the outside by the axial direction passing through the end of the turnup of the first layer of carcass reinforcement and radially towards the inside by the axial direction passing through the intersection of the straight line passing through center O of curvature of the zone of the tire that comes to bear on the rim flange, intended to accept the tire, and making an angle of 45° with the axial direction and the turnup of the first layer of carcass reinforcement.

3. The tire according to claim 1 , wherein each of the layers of carcass reinforcement has a breaking force per unit width greater than 2900 daN/dm.

4. The tire according to claim 1 , wherein the reinforcing elements of the first layer of carcass reinforcement have a thread count higher than 300 tex and preferably higher than 400 tex.

5. The tire according to claim 1 , wherein it has a load index strictly higher than 99.

6. The tire according to claim 1 , wherein the second layer of carcass reinforcement is made up of reinforcing elements between two skim layers formed of rubber compound having a secant elastic modulus under tension at 10% elongation of Mc 2 , and wherein the secant elastic modulus values under tension at 10% elongation, Mc 2 , Mj, satisfy the relationship 0.6≤Mc 2 /Mj≤4.

7. The tire according to claim 1 , wherein the layers of carcass reinforcement that are made up of reinforcing elements between two skim layers formed of rubber compound have a secant elastic modulus under tension at 10% elongation, denoted Mc 1 for the first layer of carcass reinforcement and Mc 2 for the second layer of carcass reinforcement respectively, and wherein the secant elastic modulus values under tension at 10% elongation Mc 1 , Mc 2 satisfy the relationship Mc 2 /Mc 1 ≤4.6.

8. The tire according to claim 1 , wherein, in any meridian plane, in each bead, the tire comprises a retention reinforcement surrounding the bead wire and a volume of rubber compound directly in contact with the bead wire.

9. The tire according to claim 1 , the first layer of carcass reinforcement forming a main part between the two bead wires and a turnup in each of the beads, and wherein, in any meridian plane, in each bead, the turnup of the first layer of carcass reinforcement is distant from the main part by a distance d of between 0.5 and 3.2 mm over a length L of at least 15 mm.

10. The tire according to claim 1 , wherein the reinforcing elements of the first layer of carcass reinforcement are identical to those of the second layer of carcass reinforcement.

11. The tire according to claim 1 , wherein the direction passing through the center O of curvature of the zone of the tire that comes to bear against the flange of the rim intended to accept the tire, and the axially external end of the layer of reinforcing elements made of aromatic polyamide makes an angle α of between 0 and 45° with the axial direction.

12. The tire according to claim 1 wherein the direction passing through the center O of curvature of the zone of the tire that comes to bear against the flange of the rim intended to accept the tire and the axially interior end of the layer of reinforcing elements made of aromatic polyamide makes an angle θ of between 0 and 20° with the axial direction.

13. The tire according to claim 1 , wherein the direction passing through the geometric center of the bead wire and the end of the second layer of carcass reinforcement makes an angle θ of less than 50° with the axial direction.

14. The tire according to claim 1 , wherein the distance between the end of the second layer of carcass reinforcement and the axially outermost end of the layer of reinforcing elements made of aromatic polyamide is greater than 5 mm.

Assignees

• Michelin & Cie
• Michelin Rech Tech

Inventors

• Francia Marc
• Potin Yves
• Vilcot Florian

Classifications

• B60C15/0054 Primary

  with ply turn-up portion parallel and adjacent to carcass main portion · CPC title

• B60C15/0635

  using chippers between the carcass layer and chafer rubber wrapped around the bead · CPC title

• B60C15/0018 Primary

  not folded around the bead core, e.g. floating or down ply · CPC title

• B60C2009/0253

  being different between adjacent plies · CPC title

• B60C2009/0246

  Modulus of the ply · CPC title