Compagnie Generale Des Etablissements Michelin

Michelin Recherche Et Technique S.a.

Compagnie Generale Des Etablissments Michelin

Frédéric Bourgeois

François-Xavier Bruneau

Emmanuel Igier

Patrice Fraysse

Olivier Muhlhoff

Bruno Guimard

Benoit Durand-Gasselin

Arnaud Delbast

Fabien Hellot

Aymeric Bonnet

Pascal Fickinger

The tire () for a passenger vehicle has an axially central portion and axially lateral portions. The axially central portion and each axially lateral portion satisfies just one of conditions I, II, III: I—the portion comprises no transverse cut ('), II—the portion comprises N transverse cuts (′) arranged in such a way that π×OD/N≥40 mm, III—the portion comprises N transverse cuts (′) arranged in such a way that π×OD/N≤24 mm, condition I or II being satisfied by the axially central portion or by an axially lateral portion, and condition III being satisfied by the axially central portion or by an axially lateral portion.

Low-noise tire

Passenger vehicle tire, the tread having edge parts (), provided with a plurality of transversely or obliquely oriented cuts () having a width at most equal to 2 mm and a depth at least equal to 75% of the thickness of the tread that is intended to be worn away, more than half of the cuts () comprising a protuberance that locally reduces the width of the cut () to a width at least equal to 0.2 mm and at most equal to 0.5 mm. The tread material which comes into contact with the road surface in the new state has a Shore A hardness at least equal to 48 and at most equal to 57, a loss at 60&#xb0; C. at least equal to 12% and at most equal to 20%, a glass transition temperature Tg at least equal to &#x2212;20&#xb0; C. and at most equal to &#x2212;10&#xb0; C.

Tire with improved performances having cuts with a protuberance that locally reduce a width of a cut in the tread

Tire having a predetermined direction of mounting on a vehicle. The tire tread () comprises a central rib (-) and two side ribs (), separated by circumferential grooves (-). The side ribs are made from a first rubber composition less than 50% filled with black. The central rib comprises a portion () made from a second rubber composition more than 50% filled with black, the axial width (LP) of said portion being greater than or equal to 20% of the axial width LC of the central rib. The first rubber composition has a tan &#x3b4;0 value which is greater than the tan &#x3b4;0 value of the second rubber composition, where tan &#x3b4;0 denotes the tan &#x3b4; value measured at a temperature of 0&#xb0; C. and under a stress of 0.7 mPa.

Tire comprising an improved tread

A tire tread comprising at least one groove that is delimited by two opposing walls that are connected by a groove bottom. The groove has a width and a depth and at least one resonance-noise-reducing device. The device is formed of at least one blade that is fixed to one of the walls delimiting the groove or to the groove bottom and at least partially closes the cross section of the groove. The each flexible blade comprises two main walls which close the cross section of the groove. End walls delimit the main walls and a connecting wall connecting to the tread. Each blade further comprises at least one raised rib on at least one of its main walls, and the raised rib starts from the wall or the bottom bearing the blade and extends over at least 50% of the length of the flexible blade.

Ribbed anti-noise device for a tire

Tire comprising a tread which has at least one central rib (-) and two lateral ribs (-) which are separated by circumferential grooves (-), in which tire a first lateral rib () adjacent to the outer axial edge of the tread and at least one (and preferably each) of the central ribs have a first portion () the axial width of which exceeds 2 % of the axial width of the relevant rib made and the depth of which is less than that of the relevant rib, from a rubber composition containing an elastomer and a reinforcing filler consisting predominantly of carbon black, and an axially adjacent second portion () made of a rubber composition containing an elastomer and a reinforcing filler a minority proportion of which consists of carbon black, in which the rubber compositions that make up the second portion of the first lateral rib and the second portion of the central rib all have a tanvalue which is higher than the tanvalue of the rubber compositions that form the first portion of the first lateral rib and the first portion of the central rib, the tanvalues being measured at a temperature of 0&#xb0; C. and under a stress of 0.7 MPa.

Tire with improved tread

Tire tread has a central rib (-) and two lateral ribs (-) which are separated by circumferential grooves (-). A first lateral rib () adjacent to the outer axial edge of the tread and a central rib have a first portion () the axial width of which exceeds 20% of the axial width of the relevant rib made from a first rubber composition containing an elastomer and a reinforcing filler consisting predominantly of carbon black, and an axially adjacent second portion () made of a second rubber composition containing an elastomer and a reinforcing filler a minority proportion of which consists of carbon black. The second rubber composition has a tan d0 value which is less than the tan d0 value of the first rubber composition, the tan d0 values being measured at a temperature of 0 C and under a stress of 0.7 MPa.

Tread having a plurality of generally circumferentially orientated grooves delimiting a plurality of relief elements, this tread further comprising a plurality of cut-outs in the form of transversely orientated grooves and/or slits, each relief element comprising a contact face intended to come into contact with the road and lateral faces cutting this contact face along edges intended to come into contact with a road during running, this tread having chamfers on at least a plurality of transverse edges of the relief elements, this tread having, in straight-line running, a total contact surface S comprising a part Sc in which all the transverse edges have chamfers and a part Snc in which all the transverse edges are free of chamfers, this tread having, in a cornering maneuver corresponding to a transverse acceleration of 0.3 g (where g is the acceleration due to gravity), a total footprint surface S* formed by a part Sc* comprising chamfers on all the transverse edges of its relief elements and a part Snc* free of any chamfer, this tread being such that the ratio Snc/Sc is equal to not more than 2% and that the ratio Snc*/Sc* is equal to or greater than 10%.

Tread with variable chamfers

Assembly comprising a tire and a mounting rim, the tire comprising two beads each comprising at least one annular reinforcing structure and a carcass reinforcement anchored in the two beads by a turn-up, each bead comprising a filler of a rubber composition extending radially a radial distance DBE from the radially innermost point of the annular reinforcing structure, DBE being less than or equal to 10% of the radial height H of the tire, at least one sidewall further comprising a stiffening reinforcement of metallic reinforcing elements oriented at an angle less than or equal to 10 degrees to the circumferential direction, and positioned such that the distance DAE between the radially innermost point of the annular reinforcing structure and the radially outer end of the stiffening reinforcement is greater than or equal to 20% and less than or equal to 40% of H and that the distance DAI between the radially inner point of the annular reinforcing structure and the radially inner end of the stiffening reinforcement is less than or equal to 20% of H.

Tire assembly having an improved bead and a mounting rim

Tire comprising two beads comprising a bead wire and a carcass anchored around the two bead wires by turning back, a squat filler of small height, a sidewall stiffening reinforcement which is metallic, an outer strip of soft rubber compound, placed axially on the outside of the carcass and of the filler, and a protective layer of rubber compound, wherein the assembly formed by the stiffening reinforcement and the outer strip has a thickness EB(R) and the protective layer has a thickness EE(R), R being the distance with respect to the radially innermost point of the bead wire, and wherein the thicknesses EB(R) and EE(R) satisfy a set of geometric conditions.

Tire with improved bead

Tire having two beads having an annular reinforcing structure and a carcass reinforcement anchored in the two beads by a turn-up. Each bead has a bead rubber filler extending a radial distance from the radially innermost point of the annular reinforcing structure of the bead. The radial distance is not more than 10% of the tire's radial height. A sidewall has rigidifying metal reinforcing elements oriented along an angle not more than 10&#xb0; to the circumferential direction and positioned with the distance between the radially innermost point of the annular reinforcing structure and the radially outer end of the rigidifying reinforcement between 20% and 40%, inclusive, of the tire's radial height and with the distance between the radially innermost point of the annular reinforcing structure and the radially inner end of the rigidifying reinforcement not more than 20% of the tire's radial height.

Tire with bead having specified bead filler and rigidifying reinforcement

Tread comprising at least one groove delimited by two walls facing one another, joined together by a groove bottom, this groove having a plurality of closure devices, each made up of at least one flexible blade (of thickness E suited to allowing flexing under the effect of a circulation of liquid in the groove, and secured to a wall delimiting the groove, each flexible blade bounded by a bottom wall facing the bottom of the groove, an end wall facing the other wall of the groove and a contact wall to come into contact with the roadway and lateral walls spaced apart from one another by a distance equal to the thickness E of the blade, the bottom wall of each flexible blade having a notch in the vicinity of the wall to which the blade is attached, wherein each flexible blade is connected to one of the walls delimiting the groove inside a housing (formed on the wall bearing the blade, each housing having a depth suited to containing in its entirety a notch.

Anti-noise device for tire

Tire having two beads each comprising an annular reinforcing structure and a carcass reinforcement which is anchored in the two beads by being wrapped around the annular reinforcing structure so as to form, in each bead, a main portion and a wrapped-around portion, wherein each bead comprises an apex situated between the main portion and the wrapped-around portion of the carcass reinforcement, and an outer strip positioned axially on the outside of the carcass reinforcement and of the apex, the apex and the outer strip being made of a rubber compound that has an elastic modulus G' less than or equal to 15 MPa and a viscous modulus G&#x2033; such that: G&#x2033;[MPa]&#x2266;0.2&#xb7;G&#x2032;[MPa]&#x2212;0.2 MPa, the elastic and viscous moduli being measured at 23&#xb0; C.; wherein the entity formed by the apex and the outer strip has a thickness E(r), the thickness E(r) varying such that, in the range of distances r comprised between 25 and 45% of the height H of the tire, the variation in thickness is less than or equal to &#x2212;0.25 mm/mm over at least 4% of the height H of the tire, that, in the range of distances r comprised between 15 and 35% of the height H, the variation in thickness is greater than or equal to 0.20 mm/mm over at least 2% of the height H of the tire, and that, in the range of distances r comprised between 10 and 20% of the height H of the tire, the variation in thickness is greater than or equal to &#x2212;0.10 mm/mm and less than or equal to 0.0 mm/mm over at least 5% of the height H of the tire.

Tire with improved beads

Tire comprising two beads comprising an annular reinforcing structure and a carcass reinforcement which is anchored in the two beads by being wrapped around the annular reinforcing structure so as to form, in each bead, a main portion and a wrapped-around portion, in which each bead comprises a bead filler situated between the main portion and the wrapped-around portion of the carcass reinforcement, and an outer strip positioned axially on the outside of the carcass reinforcement and of the bead filler in which the entity formed by the bead filler and the outer strip has a thickness E(r), the thickness E(r) changes as a function of the distance r such that, in the range of distances r comprised between 25 and 45% of the height H of the tire, the variation in thickness Is less than or equal to &#x2212;0.25 mm/mm over at least 4% of the height H of the tire, and in which the annular reinforcing structure has a maximum axial width DE such that the ratio where E(r)is the maximum value of the thickness E(r), is less than or equal to 10%.

In a tire having two beads, each bead has a bead filler situated at least partially between a main portion and a wrapped-around portion of a carcass reinforcement and an outer strip situated axially outside of the wrapped-around portion of the carcass reinforcement. The bead filler has a thickness E(r). An assembly formed by the bead filler and the outer strip has a thickness ET(r). For all the points of intersection of which the radial distance from the radially innermost point of the annular reinforcing structure is greater than or equal to 10% and less than or equal to 35% of the radial height H of the tire, the ratio E(r)/ET(r) is greater than or equal to 0.3 and less than or equal to 0.5.

Tire with beads including bead filler and outer strip

Tire comprising two beads comprising an annular reinforcing structure, a carcass reinforcement anchored in the two beads so as to form a main portion and a wrapped-around portion, each wrapped-around portion extending radially outwards as far as an end situated at a radial distance DEC that is less than or equal to 10% of the radial height H of the tire; each bead comprising an apex made of a rubber composition having an elastic modulus greater than 40 MPa, extending radially as far as a radial distance DEE1 comprised between 10% and 15% of the height H; each bead further comprising an outer strip made of a rubber composition that has an elastic modulus G' less than or equal to 15 MPa and a viscous modulus G&#x2033; such that: G&#x2033;[MPa]&#x2266;0.2&#xb7;G&#x2032;[MPa]&#x2212;0.2 MPa, extending at least between 20% and 25% of the height H, the apex having an axial thickness E(r) that is substantially a linear function of r, r denoting the distance with respect to the radially innermost point of the annular structure, wherein the entity formed by the apex and outer strip has a thickness ET(r) such that, in the range of distances r comprised between 25 and 45% of the height H of the tire, the variation in thickness is negative and has an absolute value that is greater than or equal to 0.25 mm/mm over at least 4% of the height H; and wherein said annular structure has a maximum axial width DE such that the ratio where ET(r)is the maximum value of the thickness ET(r), is less than 10%.

Growing community of inventors

Clermont-Ferrand, France

Frédéric Bourgeois