Tire comprising a layer of circumferential reinforcing elements

Patent metadata

Field	Value
Publication number	US-9636950-B2
Application number	US-201214351005-A
Country	US
Kind code	B2
Filing date	Oct 12, 2012
Priority date	Oct 13, 2011
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

A tire having a crown reinforcement formed of at least two working crown layers having unequal axial widths, a layer C of rubber mixture being positioned between at least the ends of the said at least two working crown layers, and the crown reinforcement having at least one layer of circumferential reinforcing elements positioned radially between two working crown layers. The distance d between the end of the axially narrowest working layer and the working layer separated from the axially narrowest working layer by the layer C of rubber mixture is such that 1.1ø<d<2.2ø, ø being the diameter of the reinforcing elements of the said at least one layer of circumferential reinforcing elements, and, in a meridian plane, the thickness of the layer C of rubber mixture is substantially uniform.

First claim

The invention claimed is:

1. A tire comprising:
a radial carcass reinforcement comprising a crown reinforcement comprising;
at least two working crown layers of reinforcing elements crossed from one layer to the other while forming, with a circumferential direction, angles of between 10° and 45° , wherein the at least two working crown layers have unequal axial widths,
a layer C of rubber mixture being positioned between at least the ends of the at least two working crown layers,
at least one layer of circumferential reinforcing elements positioned radially between two working crown layers, wherein the distance d between the end of the axially narrowest working layer and the working layer separated from the axially narrowest working layer by the layer C of rubber mixture is such that 1.1ø<d<2.2ø, ø being the diameter of the reinforcing elements of the at least one layer of circumferential reinforcing elements, and wherein, in a meridian plane, the thickness of the layer C of rubber mixture does not vary by more than 0.3 mm over the axial width between the axially interior end of the layer C and the end of the axially narrowest working layer,
wherein the axial widths of the working crown layers radially adjacent to the layer of circumferential reinforcing elements are greater than the axial width of the layer of circumferential reinforcing elements, and
wherein the working crown layers adjacent to the layer of circumferential reinforcing elements on either side of an equatorial plane and, in an immediate axial extension of the layer of circumferential reinforcing elements, coupled over an axial width, in order to be subsequently decoupled by said layer C of rubber mixture of at least over the remainder of the width common to the two working layers,

a tread, the tread being joined to two beads via two sidewalls, and
wherein the tread radially tops the crown reinforcement.

2. The tire according to claim 1 , wherein the tensile modulus of elasticity at 10% elongation of the layer C of rubber mixture is less than 8 MPa and in that the maximum tan(d) value, denoted tan(d) max , of the layer C of rubber mixture is less than 0.100.

3. The tire according to claim 2 , wherein the layer C of rubber mixture is an elastomeric mixture based on natural rubber or on synthetic polyisoprene comprising predominantly cis-1,4 enchainments and optionally at least one other diene elastomer, the natural rubber or the synthetic polyisoprene, in the case of a blend, being present at a predominant content with respect to the content of other diene elastomer(s) used, and on a reinforcing filler consisting:
a) either of carbon black with a BET specific surface of greater than 60 m 2 /g,
i. employed at a content of between 20 and 40 phr when the structural index of the carbon black using Compressed Oil Absorption Number (COAN) is greater than 85,
ii. employed at a content of between 20 and 60 phr when the structural index of the carbon black (COAN) is less than 85,

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

4. The tire according to claim 2 , further comprising at least one layer of rubber mixture B bordering the end of a working crown layer, wherein the tensile modulus of elasticity at 10% elongation of the at least one layer of rubber mixture B is less than 8 MPa and wherein the maximum tan(d) value, denoted tan(d) max , for the layer of rubber mixture B is less than 0.100.

5. The tire according to claim 2 , wherein the at least two working crown layers are each formed of reinforcing elements inserted between two calendering layers of rubber mixture, wherein the tensile modulus of elasticity at 10% elongation of at least one calendering layer of at least one working crown layer is less than 8.5 MPa and wherein the maximum tan(d) value, denoted tan(d) max , of the at least one calendering layer of at least one working crown layer is less than 0.100.

6. The tire according to claim 5 , wherein the at least one calendering layer of at least one working crown layer is an elastomeric mixture based on natural rubber or on synthetic polyisoprene predominantly comprising cis-1,4 enchainments and optionally at least one other diene elastomer, wherein the natural rubber or the synthetic polyisoprene, in the case of a blend, is present at a predominant content with respect to the content of other diene elastomer(s) used, and on a reinforcing filler consisting:
a) either of carbon black with a BET specific surface of greater than 60 m 2 /g,
i. employed at a content of between 20 and 40 phr when the structural index of the carbon black using Compressed Oil Absorption Number (COAN) is greater than 85,
ii. employed at a content of between 20 and 60 phr when the structural index of the carbon black (COAN) is less than 85,

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

7. The tire according to claim 5 , wherein the difference between the tensile modulus of elasticity at 10% elongation of the layer C of rubber mixture and the tensile modulus of elasticity at 10% elongation of the at least one calendering layer of at least one working crown layer is less than 2 MPa.

8. The tire according to claim 1 , wherein the said reinforcing elements of at least one working crown layer are saturated layered cords, at least one inner liner being sheathed with a layer consisting of a polymeric composition, such as a non-crosslinkable, crosslinkable or crosslinked rubber composition.

9. The tire according to claim 1 , wherein the difference between the axial width of the axially widest working crown layer and the axial width of the axially narrowest working crown layer is between 10 and 30 mm.

10. The tire according to claim 1 , wherein the axially widest working crown layer is radially interior to the other working crown layers.

11. The tire according to claim 1 , wherein the reinforcing elements of the at least one layer of circumferential reinforcing elements are metal reinforcing elements exhibiting a secant modulus at 0.7% elongation of between 10 and 120 GPa and a maximum tangent modulus of 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 angle formed by the reinforcing elements of the working crown layers with the c

Assignees

• Michelin & Cie
• Michelin Rech Tech

Inventors

• Domingo Alain
• Besson Jacques
• Barbarin Francois
• Sallaz Gilles
• Radulescu Robert Ciprian

Classifications

• B60C2200/06

  for heavy duty vehicles · CPC title

• Y10T152/10801

  Structure made up of two or more sets of plies wherein the reinforcing cords in one set lie in a different angular position relative to those in other sets · CPC title

• B60C1/00

  Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition · CPC title

• B60C9/185

  between adjacent or radially below the belt plies · CPC title

• B60C2009/1864

  wrapped around the edges of the belt · CPC title