Tire comprising a layer of circumferential reinforcement elements

Patent metadata

Field	Value
Publication number	US-10442247-B2
Application number	US-201515321623-A
Country	US
Kind code	B2
Filing date	May 27, 2015
Priority date	Jun 26, 2014
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

The invention relates to a tire comprising a crown reinforcement formed of at least two working crown layers each formed of reinforcing elements inserted between skim layers of rubber compound, a first layer S of polymer compound being in contact with at least one working crown layer and in contact with the carcass reinforcement and the crown reinforcement comprising at least one layer of circumferential reinforcing elements. In accordance with the invention, the elastic modulus under tension at 10% elongation of at least one skim layer of at least one working crown layer is less than 8.5 MPa, the maximum value of tan(δ), denoted tan(δ)max of the said at least one skim layer of at least one working crown layer is less than 0.100, and the complex dynamic shear modulus G*, measured at 10% and 60° C. on the return cycle, of the said first layer S of polymer compound is greater than 1.35 MPa.

First claim

The invention claimed is:

1. Tire with a radial carcass reinforcement comprising a crown reinforcement formed of at least two working crown layers each formed of reinforcing elements inserted between two skim layers of rubber compound, crossed from one layer to the other making with the circumferential direction angles comprised between 10° and 45°, a first layer of polymer compound being in contact with at least one working crown layer and in contact with the carcass reinforcement, said first layer of polymer compound extending axially as far as at least the axial end of the tread, said tread radially capping the crown reinforcement and being connected to two beads by two sidewalls, the crown reinforcement comprising at least one layer of circumferential reinforcing elements, wherein the elastic modulus under tension at 10% elongation of at least one skim layer at least one working crown layer is less than 8.5 MPa, wherein the maximum value of tan(δ), denoted tan(δ) max of said at least one skim layer of at least one working crown layer is less than 0.100, and wherein the complex dynamic shear modulus, measured at 10% and 60° C. on the return cycle, of said first layer of polymer compound is greater than 1.35 MPa,
wherein the tire further comprises a second layer of polymer compound axially in contact with the first layer of polymer compound radially between the carcass reinforcement and the radially innermost layer of reinforcing elements of the crown reinforcement, and
wherein the complex dynamic shear modulus, measured at 10% and 60° C. on the return cycle, of said second layer of polymer compound is greater than 1.35 MPa.

2. The tire according to claim 1 , wherein the complex shear modulus G*, measured at 10% and 60° C. on the return cycle, of the first layer of polymer compound is less than 2 MPa.

3. The tire according to claim 1 , wherein the maximum value of tan(δ), denoted tan(δ) max of the first layer of polymer compound is less than 0.100.

4. The tire according to claim 1 , wherein said first layer of polymer compound comprises a reinforcing filler made up of:
a) either carbon black with a BET specific surface area of between 30 and 160 m 2 /g, used in a content equal to or greater than 15 phr and less than or equal to 28 phr,
b) or a white filler of the silica and/or alumina type comprising SiOH and/or AlOH surface functional groups selected from the group formed of precipitated or pyrogenated silicas, aluminas or aluminosilicates or alternatively carbon blacks modified during or after synthesis with a specific surface area of between 30 and 260 m 2 /g used at a content greater than or equal to 15 phr and less than or equal to 55 phr,
c) or a blend of carbon black described at (a) and a white filler described at (b), in which the overall filler content is greater than or equal to 15 phr and less than equal to 50 phr and the white filler phr content is greater than or equal to the phr content of carbon black minus 5.

5. The tire according to claim 1 , wherein the said at least one skim layer of at least one working crown layer is an elastomeric compound based on natural rubber or synthetic polyisoprene with a majority of cis-1,4 chains, and possibly at least one other diene elastomer, the natural rubber or the synthetic polyisoprene in case of blending being present in a majority proportion relative to the proportion of the other diene elastomer or elastomers used, and a reinforcing filler composed of:
a) either carbon black with a BET specific surface area greater than 60 m 2 /g,
i. used at a content of between 20 and 40 phr when the carbon black oil absorption number (COAN) is greater than 85,
ii. used at a content comprised between 20 and 60 phr when the carbon black oil absorption number (COAN) is less than 85,

b) or carbon black of BET specific surface area less than 60 m 2 /g, whatever its oil absorption number, used at a content of between 20 and 80 phr,
c) or a white filler of the silica and/or alumina type comprising SiOH and/or AlOH surface functional groups selected from the group formed of precipitated or pyrogenated silicas, aluminas or aluminosilicates or alternatively carbon blacks modified during or after synthesis with BET specific surface area of between 30 and 260 m 2 /g used at a content of between 20 and 80 phr,
d) or a blend of carbon black described at (a) and/or of carbon black described at (b) and/or a white filler described at (c), in which the overall filler content is comprised between 20 and 80 phr.

6. The tire according to claim 1 , wherein the complex shear modulus, measured at 10% and 60° C. on the return cycle, of the second layer of polymer compound is less than 2 MPa.

7. The tire according to claim 1 , wherein the maximum value of tan(δ), denoted tan(δ)max, of the second layer of polymer compound is less than 0.100.

8. The tire according to claim 1 , wherein said second layer of polymer compound comprises a reinforcing filler made up of:
a) either carbon black with a BET specific surface area of between 30 and 160 m 2 /g, used in a content equal to or greater than 15 phr and less than or equal to 28 phr,
b) or a white filler of the silica and/or alumina type comprising SiOH and/or AlOH surface functional groups selected from the group formed of precipitated or pyrogenated silicas, aluminas or aluminosilicates or alternatively carbon blacks modified during or after synthesis with a specific surface area of between 30 and 260 m 2 /g used at a content greater than or equal to 15 phr and less than or equal to 55 phr,
c) or a blend of carbon black described at (a) and a white filler described at (b), in which the overall filler content is greater than or equal to 15 phr and less than equal to 50 phr and the white filler phr content is greater than or equal to the phr content of carbon black minus 5.

9. The tire according to claim 1 , wherein the said reinforcing elements of at least one working crown layer are cords with saturated layers, at least one internal layer being sheathed by a layer made of a polymer composition such as a non-crosslinkable, crosslinkable or crosslinked rubber composition.

10. The tire according to claim 1 , wherein the layer of circumferential reinforcing elements is placed radially between two working crown layers.

11. The tire according to claim 1 , wherein the reinforcing elements of at least one layer of circumferential reinforcing elements are metallic reinforcing elements having a secant modulus at 0.7% elongation comprised between 10 and 120 GPa and a maximum tangent modulus less than 150 GPa.

12. The tire according to claim 1 , wherein the reinforcing elements of the working crown layers are inextensible.

13. The tire according to claim 1 , wherein the crown reinforcement is supplemented radially on the outside by at least one additional ply, referred to as a protective ply, of reinforcing elements referred to as elastic elements, which are oriented with respect to the circumferential direction at an angle of between 10° and 45° in the same direction as the angle formed by the inextensible elements of the working ply radially adjacent to it.

14. The tire according to claim 1 , wherein the crown reinforcement further comprises a triangulation layer formed of metallic reinforcing elements making angles greater than 60° with the circumferential direction.

15. The tire according to claim 1 , wherein said at least one skim layer of at least one working crown layer is an elastomeric compound based on natural rubber or synthetic polyisoprene with a majority of cis-1,4 chains, and possibly at least one other diene elastomer, the natural rubber or

Assignees

• Michelin & Cie
• Michelin Rech Tech

Inventors

• Rehab Hichem
• Parmentier Jean-François

Classifications

• B60C9/1835 Primary

  Rubber strips or cushions at the belt edges · CPC title

• C08K3/04

  Carbon · CPC title

• B60C2001/0075

  Compositions of belt cushioning layers · CPC title

• C08K3/22

  of metals · CPC title

• B60C2009/1878

  with flat cushions or shear layers between the carcass and the belt · CPC title