Tire having optimized performance in terms of rolling resistance without impairing the industrial performance

Patent metadata

Field	Value
Publication number	US-2024270026-A1
Application number	US-202218567240-A
Country	US
Kind code	A1
Filing date	May 23, 2022
Priority date	Jun 7, 2021
Publication date	Aug 15, 2024
Grant date	—

Abstract

The rolling resistance of a tire has been improved without degrading industrial performance. The sidewall ( 30 ) consists of two sub-layers. A first sub-layer (FE 1 ) of thickness E1 and volume V1 provides the expected protection functions of a sidewall as the outer wall of the tire, and a second sub-layer of the sidewall (FE 2 ) of thickness E2 and volume V2 is optimized at low hysteresis to improve rolling resistance. The ratio V1/(V1+V2) of the volumes of the two sub-layers (FE 1, FE 2 ) is less than or equal to 0.3. The elongation at break of the compound of FE 1 is greater than or equal to 200% measured at a temperature of 100° C., and the viscoelastic loss of the compound of FE 2, Tan(δ)max, is less than or equal to 0.10.

First claim

1 .- 15 . (canceled)

16 . A tire ( 1 ) for a passenger vehicle comprising in a meridian plane:
two beads ( 50 ) intended to be mounted on a rim, two sidewall layers ( 30 ) connected to the beads ( 50 ), a crown ( 20 ) comprising a tread ( 10 ), the crown ( 20 ) having a first side connected to a radially outer end of one of the two sidewall layers ( 30 ) and having a second side connected to a radially outer end of the other of the two sidewall layers ( 30 ); and at least one carcass reinforcement ( 90 ) extending from the two beads ( 50 ) to the crown ( 20 ), the at least one carcass reinforcement ( 90 ) comprising a plurality of carcass reinforcement elements and being anchored in the two beads ( 50 ) by a turn-up around an annular reinforcement structure ( 51 ), so as to form in each bead a main part ( 52 ) and a turn-up ( 53 ), wherein each sidewall layer ( 30 ) consists of two axially superposed sub-layers (FE 1 , FE 2 ), a first sidewall sub-layer (FE 1 ) delimited by a first axially outermost side constituting a lateral wall of the tire in contact with ambient air, and a second axially inner side defined such that the sidewall sub-layer (FE 1 ) has an average axial thickness E1, and occupying a volume V1, and a second sidewall sub-layer (FE 2 ), a first side of which coincides with the second axially inner side of the first sidewall sub-layer (FE 1 ), and a second, axially inner side of which is at least partially in contact with the carcass reinforcement ( 50 ), the sidewall sub-layer (FE 2 ) having an average axial thickness E2, and occupying a volume V2, wherein the thickness E1 of the first sidewall sub-layer (FE 1 ) is greater than or equal to 0.7 mm, wherein a ratio V1/(V1+V2) is less than or equal to 0.3, wherein an elongation at break of an elastomer compound constituting the first sidewall sub-layer (FE 1 ) is greater than or equal to 200% measured at a temperature of 100° C., and wherein a viscoelastic loss of the second sidewall sub-layer (FE 2 ), Tan(δ) max, is less than or equal to 0.10.

17 . The tire ( 1 ) according to claim 16 , wherein an elastic shear modulus of the second sidewall sub-layer FE 2 is in a range [1.5; 10] MPa.

18 . The tire ( 1 ) according to claim 16 , each bead ( 50 ) comprising a filling layer ( 70 ) comprised at least in part between a main part of the carcass reinforcement ( 52 ), the turn-up ( 53 ) of the carcass reinforcement and a radially outer portion of the annular reinforcement structure, wherein an elastomer compound constituting the filling layer has a viscoelastic loss Tan(δ)max of less than or equal to 0.1.

19 . The tire according to claim 16 , wherein each bead comprises a lateral reinforcement layer ( 60 ) consisting of an elastomer compound occupying a volume comprised at least in part between the second sidewall layer ( 30 ) and the turn-up ( 53 ) of the carcass reinforcement.

20 . The tire ( 1 ) according to claim 19 , wherein the lateral reinforcement layer ( 60 ) of each bead consists of an elastomer compound a viscoelastic loss Tan(δ)max of which is less than or equal to 0.10.

21 . The tire ( 1 ) according to claim 16 , in each bead ( 50 ) a rim contact curve comprising points of the tire ( 1 ) in contact with the rim ( 100 ),
the rim contact curve connecting a first point Ml of the tire positioned outermost axially, and in contact with the rim, and a second point M 2 of the tire in contact with the rim and situated in a middle of a rectilinear portion ( 130 ) connecting a flange ( 120 ) to a seat ( 110 ) of the rim, the tire ( 1 ) further comprising two sections in a vertical meridian section of the tire when inflated, mounted on a rim, and compressed against the ground by a vertical load ( 250 ), where the vertical load and an inflation pressure are determined in a specification standard, a first section being located in a contact area and a second section being located on an opposite side to the first section in relation to an axis of rotation of the tire, in the first section located in the contact area, in at least a first bead, a length of the rim contact curve, LADC, being measured, and in the second section located opposite the contact area in relation to the axis of rotation of the tire, in at least a second bead, a length of the rim contact curve, LCJ, being measured, wherein a ratio of difference in the lengths of the rim contact curves of the two sections, 100*(LADC−LCJ)/LCJ, is greater than or equal to 30%.

22 . The tire ( 1 ) according to claim 21 , wherein the ratio of the difference in the lengths of the rim contact curves of the two sections, 100*(LADC−LCJ)/LCJ, is greater than or equal to 40%.

23 . The tire ( 1 ) according to claim 16 , a distance DRB being a radial distance from a radially outer end of the filling layer ( 70 ), wherein the distance DRB is less than or equal to 50% of a radial height H of the tire ( 1 ).

24 . The tire ( 1 ) according to claim 19 , a distance DRI being a radial distance from a radially inner end of the lateral reinforcement layer ( 60 ) to a straight line (HH′), wherein the radial distance DRI is in a range [5%; 20%] of a radial height H of the tire ( 1 ).

25 . The tire ( 1 ) according to claim 19 , a distance DRL being a radial distance from a radially outer end of the lateral reinforcement layer ( 60 ) to a straight line (HH′), wherein the radial distance DRL is greater than or equal to 25% of a radial height H of the tire ( 1 ).

26 . The tire ( 1 ) according to claim 16 , wherein the turn-up ( 53 ) of the carcass reinforcement ( 90 ) is pressed against the main part ( 52 ) of the carcass reinforcement ( 90 ) over its entire height radially externally.

27 . The tire ( 1 ) according to claim 16 , wherein the tire further comprises a reinforcement of the bead ( 50 ) axially externally to the turn-up ( 53 ) of the carcass reinforcement ( 90 ), and axially internally to the sidewall ( 30 ).

28 . The tire ( 1 ) according to claim 19 , wherein an elastomer compound constituting at least one layer among the filling layer ( 70 ), the lateral reinforcement layer ( 60 ), and the sidewall sub-layer (FE 2 ) has a composition based on a diene elastomer, a crosslinking system, a reinforcing filler, and carbon black type N550, at an overall rate of between 50 and 75 phr.

29 . The tire ( 1 ) according to claim 28 , wherein an elastomer compound constituting the filling layer ( 70 ), an elastomer compound constituting the lateral reinforcement layer ( 60 ), and an elastomer compound constituting the sidewall sub-layer (FE 2 ) have the same composition.

30 . The tire ( 1 ) according to claim 16 , wherein the two sidewall sub-layers (FE 1 , FE 2 ) are manufactured by a co-extrusion process.

Assignees

• Michelin & Cie

Inventors

• Gander Sophie
• Roty Gael
• Ferigo Herve

Classifications

• B60C15/0628

  comprising a bead reinforcing layer · CPC title

• B60C15/0009

  features of the carcass terminal portion · CPC title

• B60C2015/061

  Dimensions of the bead filler in terms of numerical values or ratio in proportion to section height · CPC title

• B60C15/024

  Bead contour, e.g. lips, grooves, or ribs · CPC title

• B60C2015/0621

  adjacent to the carcass turnup portion · CPC title