Tires with hybrid lateral cutting

Abstract

The tire (10) comprises what are known as hybrid lateral cuts on the first and second axial sides (P1) and comprises a narrow axially inner portion (80) having a width at the bottom of the cut (94) ranging from 0.2 mm to 0.6 mm; and a wide axially outer portion (82) having a width at the bottom of the cut (94) ranging from 0.7 mm to 5.0 mm. Each hybrid lateral cut has a bottom surface (94), all of which are located radially outward of the interface (114) between the tread layer (110) and the support layer (112). The bottom surface (94) of the narrow axially inner portion (80) is located at a radial distance (di) strictly greater than the radial distance (de) from the interface (114) at which the bottom surface (94) of the wide axially outer portion (82) is located.

Description

[Technical Field]

[0001] The present invention relates to passenger vehicle tires. A tire means a casing intended to cooperate with a support element such as a rim to form a cavity, which cavity can be pressurized to a pressure exceeding atmospheric pressure. The tire according to the present invention has a substantially toroidal structure that exhibits rotational symmetry about the main axis of the tire. [Background Art]

[0002] Passenger vehicle tires sold under the MICHELIN® trademark as the PRIMACY4® series are known from the prior art. Such tires comprise a tread intended to contact the ground via a tread surface supported by a tread layer during running. The tire also comprises a support layer for the tread layer, also called a sublayer, disposed radially inward of the tread layer.

[0003] The tread comprises main circumferential grooves having a depth of 50% or more of the tread pattern height, including first and second axially outer main circumferential grooves on both sides of the center plane of the tire. The first and second axially outer main circumferential grooves are the axially outermost main circumferential grooves of the tread.

[0004] The tread comprises ribs each disposed axially between two adjacent main circumferential grooves and axially delimited by said two adjacent main circumferential grooves. The ribs in particular comprise a first axial side portion and a second axial side portion respectively disposed axially outward of the first axially outer main circumferential groove and the second axially outer main circumferential groove.

[0005] Each of the first and second axial side portions comprises a lateral groove, and the lateral groove comprises, on the bottom surface thereof, a sipe having a width equal to 0.4 mm over the entire curved length of the sipe.

[0006] It has been noted that this tire may optionally exhibit chunking in a portion of the tread at the first and second axial side portions.

[0007] The tire is also publicly known from U.S. Patent Nos. 9085201, 10864775, 2013 / 112325, and 10449807. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] U.S. Patent No. 9085201 [Patent Document 2] U.S. Patent No. 10864775 [Patent Document 3] U.S. Patent No. 2013 / 112325 [Patent Document 4] U.S. Patent No. 10449807 [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention aims to reduce, or even eliminate, the presence of this chunking without excessively impairing rolling resistance and grip performance on wet ground. [Means for solving the problem]

[0010] Therefore, the present invention relates to a passenger car tire having a tread intended to contact the ground via the tread surface during driving, wherein the tread is - A main circumferential cut having a depth of 50% or more of the tread pattern height and comprising first and second axially outer main circumferential cuts arranged on both axial sides of the central surface of the tire, wherein the first and second axially outer main circumferential cuts are the outermost axial main circumferential cuts of the tread, - A first axial side portion is positioned axially outward of the first axial outward main circumferential cut and extends axially from the first axial edge of the tread surface to the first axial outward main circumferential cut, - A second axial side portion is positioned axially outward of the second axial outward main circumferential cut and extends axially from the second axial edge of the tread surface to the second axial outward main circumferential cut, The tire comprises a tread layer and a support layer for the tread layer, with the support layer positioned radially inward of the tread layer. The tread is provided with so-called hybrid lateral cuts, which are at least partially made on at least one of the first and second axial sides, and each hybrid lateral cut is - A so-called narrow axial inner portion having a width in the range of 0.2 mm to 0.6 mm at the bottom surface of the cut, wherein the narrow axial inner portion is the innermost axial portion of the hybrid lateral cut in at least one of the first and second axial sides, - A so-called wide axial outer portion having a width in the range of 0.7 mm to 5.0 mm at the bottom surface of the cut, communicating with the narrow axial inner portion, and positioned axially outside the narrow axial inner portion, wherein the wide axial outer portion is the outermost axial portion of the hybrid lateral cut in at least one of the first and second axial sides, Equipped with, Each hybrid lateral cut has a hybrid lateral cut bottom surface, and the entire bottom surface of each hybrid lateral cut is positioned radially outward from the interface between the tread layer and the support layer. At least a portion of the bottom surface of the inner portion in the narrow axis direction is positioned at a radial distance that is strictly greater than the radial distance from the interface to which at least a portion of the bottom surface of the outer portion in the wide axis direction is positioned.

[0011] The inventors of the present invention understand that during the molding of a tire that allows for the creation of sipes on the axial sides, chunking occurs as the uncured elastomer composition of the axial side, or each axial side, undergoes penetration by the molding element for forming each sipe, in this case, the sipe blade. The inventors understand that this penetration is greater the narrower the width of the sipe base or the deeper the sipe. The thinner the sipe blade, the deeper it can cut into the elastomer composition of the axial side, or each axial side. Furthermore, if the sipe blade penetrates deeply into the elastomer composition, it may penetrate the interface between the tread layer and the support layer, which has the effect of shifting the support layer radially outward. Such radial outward shift of the support layer, particularly the support layer on the axial outer portion of the axial side, causes an interface to appear on the tread surface when the tire is significantly worn. Since such an interface is not designed to contact the ground on which the tire travels, it deteriorates rapidly, resulting in the chunking described above.

[0012] Faced with these problems, the inventors of the present invention designed a hybrid lateral cut with its bottom surface positioned radially outward from the interface between the tread layer and the support layer, so that the hybrid lateral cut does not penetrate this interface. In other words, the bottom surface of each hybrid lateral cut does not interfere with this interface.

[0013] Firstly, in this invention, the portion of the tread most prone to chunking includes the wide axial outer portion of the hybrid lateral cuts. The inventors of this invention have focused on the fact that, unlike sipe molding, molding lateral cuts with a width of 0.7 mm or more does not result in radial outward movement of the interface due to penetration, but rather radial inward movement due to molding pressure, thereby reducing the appearance of the interface on the tire surface and consequently reducing chunking.

[0014] Secondly, by positioning a portion of the bottom surface of the narrow-axis inner portion further radially away from the interface than a portion of the bottom surface of the wide-axis outer portion, the portion of the interface positioned alongside the narrow-axis inner portion is less likely to be penetrated by the molding element used to shape the narrow-axis inner portion. Thus, the risk of chunking is reduced.

[0015] The radial distance between the bottom surface of the portion and the interface is the distance measured in the radial direction. The distance from a given portion is the distance measured for each point in that portion. Therefore, if all points of the bottom surface of the inner portion in the narrow axis direction are positioned at a radial distance that is strictly greater than the distance at which all points of the corresponding portion of the bottom surface of the outer portion in the wide axis direction are positioned, then the corresponding portion of the bottom surface of the inner portion in the narrow axis direction is positioned radially further from the interface than the corresponding portion of the bottom surface of the outer portion in the wide axis direction.

[0016] Furthermore, the hybrid lateral cuts in the tire according to the present invention make it possible to maintain both rolling resistance performance and grip performance on wet surfaces. These lateral cuts are called hybrid because they consist of two parts, one narrow and the other wide.

[0017] The narrow portion of each hybrid lateral cut is located in the tread area where the tread height is relatively large, as it is the innermost axial portion of the hybrid lateral cut on the axial side. The greater the tread height, the greater the Poisson effect, and the presence of the cut worsens rolling resistance. Because the width of the narrow axial inner portion is relatively small, the two main sides of the narrow axial inner portion can come into contact with each other when the tire passes over the contact patch, limiting the Poisson effect and reducing rolling resistance. The wide axial outer portion is located in the tread area where the tread height is inevitably smaller due to the curvature of the tire, as it is the outermost axial portion of the hybrid lateral cut on the axial side. Therefore, the Poisson effect is small here, and the width of the wide axial outer portion has almost no adverse effect on rolling resistance.

[0018] Furthermore, the wide axially outer portion of each hybrid lateral notch enables effective water drainage, and since the width of the bottom surface of the notch is relatively large, in any case, drainage performance is improved compared to prior art tires.

[0019] The narrow axially inner portion can be compared to a sipe, and the wide axially outer portion can be compared to a groove as long as it is sufficiently wide. A sipe is configured such that the distance between its main side faces is adapted to at least partially bring the main side faces defining the sipe into contact with each other at the contact patch, especially when the tire is new and under normal driving conditions including, in particular, when the tire is at nominal pressure under nominal load. A groove is configured such that the distance between its main side faces prevents the main side faces from coming into contact with each other under normal driving conditions, including especially when the tire is at nominal pressure under nominal load.

[0020] Conventionally, the tread surface is axially delimited by first and second axial edges. The first and second axial edges of the tread surface are determined for a tire mounted on a nominal rim and inflated to nominal pressure in accordance with the standards of the European Tyre and Rim Technical Organisation, or "ETRTO" standards (2019). The first and second axial edges of the tread surface are arranged on both sides of the center plane of the tire and formed by lines substantially parallel to the circumferential direction of the tire. If there is a clear boundary between the tread surface and the remainder of the tire, the first and second axial edges of the tread surface can be easily determined. When the tread surface is continuous with the outer surface of the tire sidewall, each of the first and second axial edges passes through a point in the meridional section, at which point the angle formed between the tangent to the tread surface passing through this point and a straight line parallel to the axial direction is equal to 30°. If there are multiple points at which the absolute value of the angle equals 30° in the meridional section, the radially outermost point is used.

[0021] The support layer of the tire according to the present invention is not intended to come into contact with the ground during travel when the tire wear is smaller than the wear corresponding to the regulated wear threshold, and this wear threshold is indicated on the tire by, for example, a regulated wear indicator. In other words, the interface between the tread layer and the support layer is arranged radially inward of a plane parallel to the tread surface of a new tire over at least 90%, preferably 100%, of its curved length, and passes through the radially outermost point of the regulated wear indicator. Such a support layer is in direct contact with the tread layer. The support layer is arranged radially inward of the tread layer over the entire axial width of the support layer. The support layer is not a tread layer located radially inward of the radially outer tread layer.

[0022] The tread layer may comprise a single elastomer composition or a plurality of elastomer compositions arranged to optimize other performance criteria of the tire, and having optimized radial and axial distribution particularly as described in WO 2015 / 032601, WO 2012 / 175444, EP 3508354, EP 2594413 and WO 2009 / 124816.

[0023] Said or each of the first and second axial sides of the tread may of course comprise circumferential incisions having a depth of strictly less than 50% of the tread pattern height, together with other lateral incisions that do not have the characteristics of hybrid lateral incisions.

[0024] For a new tire, the depth of an incision or an incision portion is the maximum radial distance between the bottom surface of the incision or incision portion and its projection onto the ground during travel. The maximum value of the incision depth is referred to as the tread pattern height.

[0025] The notch or notch portion has two main characteristic dimensions on the tread surface, width and curve length, such that the curve length is at least twice the width. Thus, the notch or notch portion is defined by at least two main sides that determine its curve length and are connected at the bottom surface, and these two main sides are separated from each other by a non-zero distance called the width of the notch or notch portion.

[0026] For new tires, the width of the notch or notch portion is, by default, the maximum distance between two principal sides, measured at the radial point coinciding with the tread surface if the notch or notch portion is not chamfered, and at the radially outermost point of the notch or notch portion within the chamfered portion if the notch or notch portion is chamfered. This width is measured substantially perpendicular to the principal sides. If a width other than the default width is specified, for example, if a width at a specific point is specified, that width is equal to the distance between two principal sides at a specific point on the bottom surface of the notch or notch portion. In the present invention, regardless of whether or not the hybrid lateral notch is chamfered, the width at the bottom surface of the notch is equal to the distance between two principal sides measured at the bottom surface of the corresponding portion of the notch.

[0027] The cut or cut portion can be in the lateral or circumferential direction.

[0028] A lateral cut is designed to extend in an average direction such that the cut forms an angle of more than 30°, preferably 45° or more, with respect to the circumferential direction of the tire, i.e., an angle of 60° or less, preferably more than 45°, with respect to the axial direction of the tire. The average direction is the shortest curve connecting the two ends of the cut and is parallel to the tread surface. A lateral cut or cut portion can be continuous, i.e., not interrupted by a tread pattern block or another cut, so that the two main sides determining its length are uninterrupted over the length of the lateral cut or cut portion. A lateral cut can similarly be discontinuous, i.e., interrupted by one or more tread pattern blocks and / or one or more cuts, so that the two main sides determining its length are interrupted by one or more tread pattern blocks and / or one or more cuts.

[0029] A circumferential cut is such that the cut or a portion thereof extends in an average direction that forms an angle of 30° or less, preferably 10° or less, with the circumferential direction of the tire, i.e., an angle of exactly 60° or more, preferably exactly 80° or more, with the axial direction of the tire. The average direction is the shortest curve connecting the two ends of the cut and is parallel to the tread surface. In the case of a continuous circumferential cut, its ends coincide with each other and are connected by a curve that encircles the tire. A circumferential cut can be continuous, i.e., not interrupted by a tread pattern block or another cut, so that the two main sides that determine its length are uninterrupted around the entire circumference of the tire. Similarly, a circumferential cut can be discontinuous, i.e., interrupted by one or more tread pattern blocks and / or one or more cuts, so that the two main sides that determine its length are interrupted by one or more tread pattern blocks and / or one or more cuts around the entire circumference of the tire.

[0030] In the case of a lateral cut or a lateral cut portion, its side surfaces are called the front and rear surfaces, and each has a front edge and a rear edge, with the front edge being the edge that enters the contact surface before the rear edge with respect to a given circumferential line.

[0031] In embodiments that allow for optional improvement of braking on dry ground, the hybrid lateral cut is provided with a chamfer. The chamfer of the hybrid lateral cut can be a square chamfer or a rounded chamfer. A square chamfer is formed by a flat surface inclined with respect to the front and rear surfaces extending to a front or rear edge that circumferentially divides the hybrid lateral cut. A rounded chamfer is formed by a curved surface extending tangentially into the front or rear surface. The chamfer of the hybrid lateral cut is characterized by a height and width equal to the radial distance and the distance perpendicular to the front or rear surface between the point common to the front or rear surface extended by the chamfer and the front or rear edge that circumferentially divides the hybrid lateral cut.

[0032] In some embodiments, to allow for optional improvement of braking on wet ground, a chamfer is provided on at least one of the main circumferential cuts. The chamfer of the circumferential cut can be a square chamfer or a round chamfer. A square chamfer is formed by a flat surface inclined with respect to the axial front and rear surfaces extending to the axial front or rear edge that divides the circumferential cut axially. A round chamfer is formed by a curved surface extending tangentially into the axial front or rear surface. The chamfer of the circumferential cut is characterized by a height and width equal to the radial distance and axial distance, respectively, between the axial inner or outer surface extended by the chamfer and the axial front or rear edge that divides the circumferential cut axially.

[0033] The tire according to the present invention has a substantially annular shape centered on a rotational symmetry axis substantially coinciding with the tire's axis of rotation. This rotational symmetry axis defines three directions conventionally used by those skilled in the art: axial, circumferential, and radial.

[0034] The axial direction refers to the direction that is substantially parallel to the tire's axis of rotational symmetry, i.e., the tire's axis of rotation.

[0035] The circumferential direction refers to the direction that is substantially perpendicular to both the axial direction and the radius of the tire (in other words, the direction tangent to the circle centered on the tire's axis of rotation).

[0036] The radial direction refers to the direction along the radius of the tire, that is, any direction that intersects the tire's axis of rotation and is substantially perpendicular to that axis.

[0037] The center plane of the tire (indicated by M) refers to a plane located midway between the two beads in the axial direction, passing through the axial center of the crown reinforcement, and perpendicular to the tire's axis of rotation.

[0038] The tire's equatorial plane (denoted as E) refers to the plane in the meridional section that is perpendicular to the central plane and radially, and passes through the tire's equator. The tire's equator is the axis in the meridional section (a plane perpendicular to the circumferential direction and parallel to the radial and axial directions) that is parallel to the tire's axis of rotation and is equidistant from the radially outermost point of the tread intended to contact the ground and the radially innermost point of the tire intended to contact a support, such as the rim, where the distance between these two points is equal to H.

[0039] The meridional plane is a plane that is parallel to and contains the axis of rotation of a tire, and is perpendicular to the circumferential direction.

[0040] "Radially inward" and "radially outward" mean "closer to the tire's axis of rotation" and "farther from the tire's axis of rotation," respectively. "Axially inward" and "axially outward" mean "closer to the tire's center plane" and "farther from the tire's center plane," respectively.

[0041] The term "bead" refers to the portion of a tire intended to be mounted to a mounting support, such as a wheel with a rim. Therefore, in detail, each bead is intended to contact the flange of the rim, enabling the tire to be mounted.

[0042] The expression "between a and b" indicates a range of values ​​that extends from greater than a to less than b (i.e., excluding the endpoints a and b), whereas the expression "from a to b" indicates a range of values ​​that extends from a to b (i.e., including the exact endpoints a and b).

[0043] In a preferred embodiment of the present invention, the tire is intended for passenger cars as defined in accordance with the European Tire and Rim Technology Organization or the "ETRTO" standard (2019). Such a tire has a meridional cross-section characterized by a section height H and a nominal section width S in accordance with the European Tire and Rim Technology Organization or the "ETRTO" standard (2019), in which case the ratio H / S, expressed as a percentage, is equal to a maximum of 90, preferably a maximum of 80, more preferably a maximum of 70, at least 30, preferably at least 40, and the nominal section width S is equal to at least 115 mm, preferably at least 155 mm, more preferably at least 175 mm, at a maximum of 285 mm, preferably at a maximum of 315 mm, more preferably at a maximum of 285 mm, and even more preferably at a maximum of 255 mm. Furthermore, the diameter D in the rim flange that defines the diameter of the tire mounting rim is equal to at least 12 inches, preferably at least 16 inches, and at most 24 inches, preferably at most 20 inches.

[0044] Optionally and preferably, each main circumferential cut has a depth of 75% or more, more preferably 90% or more, of the tread pattern height.

[0045] In embodiments where the main circumferential cuts are relatively deep and suitable for passenger car tires, each main circumferential cut has a depth ranging from 4.0 mm to the tread pattern height, preferably from 5.0 mm to the tread pattern height, and more preferably from 5.5 mm to the tread pattern height.

[0046] In an embodiment suitable for passenger car tires, where the main circumferential grooves are relatively wide, each main circumferential groove has an axial width of 1.0 mm or more, preferably 5.0 mm or more, and more preferably in the range of 5.0 mm to 20.0 mm.

[0047] In optional embodiments, at least one of the first and second axial sides may be provided with at least one additional circumferential notch having a depth of strictly less than 50% of the tread pattern height, preferably 30% or less of the tread pattern height, and more preferably in the range of 10% to 30% of the tread pattern height.

[0048] In some embodiments, the inner portion in the narrow axis direction and the outer portion in the wide axis direction are adjacent. Adjacent means that no other portion intervenes axially between the inner portion in the narrow axis direction and the outer portion in the wide axis direction.

[0049] In a favorable optional embodiment, each principal surface of the hybrid transverse cut is connected to the bottom surface of the hybrid transverse cut by a fillet. The presence of the fillet reduces the formation of cracks, which are precursors to chunking. As a result, the occurrence of chunking is reduced. This reduction in crack formation is more effective the larger the radius of curvature of each fillet.

[0050] In an advantageous but discretionary embodiment that allows for further reduction of chunking, at least 60%, preferably at least 75%, of the curve length of the narrow axial inner portion is positioned at a radial distance strictly greater than the average radial distance from the interface where the bottom surface of the wide axial outer portion is located.

[0051] The longer the curve length of the narrow-axis inner portion located at a sufficient radial distance from the interface, the lower the risk of chunking. However, the bottom surface of the narrow-axis inner portion can be locally very close to the interface while still reducing the risk of chunking.

[0052] Whether hybrid or not, the curve length of a lateral cut or a portion thereof is the length measured along a curve that passes equidistant from the leading and trailing edges between the ends of the lateral cut or a portion thereof.

[0053] In an advantageous but optional embodiment that allows for the reduction of chunking occurrence as much as possible, the bottom surface of the narrow-axis inner portion is positioned at an average radial distance that is strictly greater than the average radial distance from the interface to which the bottom surface of the wide-axis outer portion is positioned.

[0054] The average radial distance is the average of the radial distances measured along a given portion between the interface and the bottom surface of that portion.

[0055] Therefore, in some embodiments where the bottom surface of the narrow-axis inner portion is locally closer to the interface than the wide-axis outer portion, the risk of chunking is still reduced.

[0056] In a preferred, optional embodiment, width Hiro Axial axis outside The average radial distance between the bottom surface of the side portion and the interface is in the range of 0.3 mm to 1.0 mm, preferably 0.4 mm to 0.9 mm.

[0057] In a preferred, optional embodiment, width narrow Axial axis Inside The average radial distance between the bottom surface of the side portion and the interface is in the range of 0.5 mm to 1.5 mm, preferably 0.6 mm to 1.2 mm.

[0058] In optional embodiments, at least a portion of the interface portion arranged radially alongside the narrow axis inner portion is located radially outward from at least a portion of the interface portion arranged radially alongside the wide axis inner portion.

[0059] More preferably, the portion of the interface aligned radially with the inner portion in the narrow axis direction is located radially outward from the portion of the interface aligned radially with the inner portion in the wide axis direction.

[0060] Therefore, a support layer that is radially higher in the vicinity of the first and second main circumferential cuts, or in the vicinity of each of the first and second main circumferential cuts, can be advantageously used without concern about increasing the risk of chunking. Such a support layer makes it possible to optimize the tire performance, for example, the braking performance on wet ground or the rolling resistance performance, as described in the application filed under international application PCT / FR2021 / 050698.

[0061] The radially positioned interface portion adjacent to the narrow axial inner portion is an interface portion demarcated by its axial ends, defined by two circumferential planes perpendicular to the tire's axis of rotation and passing through the axial ends of the narrow axial inner portion, respectively. Similarly, the radially positioned interface portion adjacent to the wide axial outer portion is an interface portion demarcated by its axial ends, defined by two circumferential planes perpendicular to the tire's axis of rotation and passing through the axial ends of the wide axial outer portion, respectively.

[0062] Optimally but voluntarily, the tread features hybrid lateral cuts partially formed on each of the first and second axial sides.

[0063] Optionally and advantageously, at least 50%, preferably at least 75%, more preferably at least 90% of the lateral cuts made at least partially on at least one of the first and second axial sides are hybrid lateral cuts.

[0064] Therefore, reducing the number of lateral cuts other than hybrid lateral cuts reduces the risk of chunking, especially when the lateral cuts other than hybrid lateral cuts are sipes. If the lateral cuts other than hybrid lateral cuts are grooves, the rolling resistance of the tire is also reduced.

[0065] In a preferred but optional embodiment, the narrow axial inner portion has a curve length equal to at least 20% and up to 75% of the curve length of each hybrid lateral cut portion made on at least one of the first and second axial sides.

[0066] The longer the curve length of the inner portion in the narrow axis direction, the greater the reduction in rolling resistance. However, if the curve length of the inner portion in the narrow axis direction is too long, the length of the outer portion in the wide axis direction will be insufficient, resulting in inadequate drainage.

[0067] Since the tread is intended to contact the ground via the tread surface when the tire is running, this curve length is consequently determined in the relevant portion of the tread and is therefore limited to the tread surface and thus to the first and second axial sides.

[0068] Optionally, to optimize rolling resistance, the width of the narrow axial inner portion at the bottom of the notch ranges from 0.2 mm to 0.5 mm.

[0069] In an advantageous embodiment suitable for passenger car tires, the narrow axial inner portion has a depth ranging from 2.0 mm to 5.5 mm, preferably from 3.0 mm to 5.0 mm.

[0070] Optionally, to optimize drainage, the width of the wide axial outer portion at the bottom of the cut is in the range of 1.0 mm to 5.0 mm, preferably 2.0 mm to 4.5 mm.

[0071] In an advantageous embodiment suitable for passenger car tires, the wide axial outer portion has a depth ranging from 2.0 mm to 5.5 mm, preferably from 3.0 mm to 5.0 mm.

[0072] In an optional embodiment that allows for the reduction of noise generated from the tire tread pattern, each hybrid lateral cut is, - A so-called inclined axial inner portion, formed on at least one of the first and second axial sides, having an average angle of 15° or more, preferably 20° or more, with respect to the axial direction, which is the inclined axial inner portion that is the innermost axial portion of the hybrid lateral cut on at least one of the first and second axial sides, -A so-called linear axial outer portion, formed on at least one of the first and second axial sides, having an average angle in the axial direction that is strictly smaller than the average angle of the inclined axial inner portion, and positioned axially outside the inclined axial inner portion, which is the linear axial outer portion that is the outermost axial portion of the hybrid lateral cut in at least one of the first and second axial sides, It is equipped with.

[0073] In the portion of the tread corresponding to the axially inner portion of the hybrid lateral cut, the contact surface is straight. Conversely, in the portion of the tread corresponding to the axially outer portion of the hybrid lateral cut, the contact surface is rounded due to the curvature of the tire. Thus, the leading edge of the inclined axially inner portion makes contact with the ground gradually, i.e., over a relatively long time interval, due to the relatively large angle in the inclined axially inner portion and the straightness of the contact surface. This limits noise compared to cuts that form a nearly zero mean angle with the axial direction, where the entire leading edge makes contact with the ground simultaneously. Similarly, due to the small angle and rounded contact surface in the linear axially outer portion, the leading edge also makes contact with the ground gradually, which also contributes to noise suppression.

[0074] The mean angle of a particular portion is determined using a straight line extending between two endpoints of that portion, where the two endpoints are located at both ends of the portion and are equidistant from the leading and trailing edges of each end of that portion.

[0075] In some embodiments, the inner portion in the inclined axis direction and the outer portion in the linear axis direction are adjacent. Adjacent means that no other portion intervenes axially between the inner portion in the inclined axis direction and the outer portion in the linear axis direction.

[0076] In some optional embodiments, the average angle of the linear axial outer portion is strictly less than 25°, preferably 20° or less, and more preferably 15° or less.

[0077] The optional, narrow-axis inner portion includes at least a part of the inclined-axis inner portion, and the wide-axis outer portion includes at least a part of the linear-axis outer portion.

[0078] In the first configuration of the inclined axis direction inner portion and the linear axis direction outer portion, the width narrow axis direction inner portion is - The entire inner portion in the direction of the inclination axis, - The first part of the linear axial outer portion, Including the wide axial outer portion, - a second part of the straight axial outer part, Includes.

[0079] In the second configuration of the inclined axis direction inner portion and the linear axis direction outer portion, the width narrow axis direction inner portion is - First part of the inward portion in the axial direction of the inclination Including the wide axial outer portion, - The second part of the inward portion in the inclined axis direction, - The entire outer portion in the linear axial direction, Includes.

[0080] In the third configuration of the inclined axis direction inner portion and the linear axis direction outer portion, the narrow axis direction inner portion is composed of the inclined axis direction inner portion, and the wide axis direction outer portion is composed of the linear axis direction outer portion.

[0081] In optional embodiments, it can be assumed that the narrow axial inner portion does not appear in either of the adjacent first and second axial outer main circumferential cuts. In these embodiments, the hybrid lateral cut is said to be blind.

[0082] In other optional preferred embodiments, the narrow axial inner portion appears in one of the adjacent first and second axial outer main circumferential cuts. Thus, the mobility of the tread pattern is enhanced compared to tires with blind hybrid lateral cuts, improving tire flattening and, consequently, rolling resistance.

[0083] In a preferred optional embodiment, each hybrid lateral cut is made on the axially outward side of at least one of the first and second axial sides and includes an axial end portion that communicates with the wider axial outward portion.

[0084] This promotes water drainage from the tread surface, which represents the surface of the tire tread that is in contact with the ground.

[0085] In an optional embodiment that allows for advantageous improvement of the aerodynamic characteristics of the tire, - The first tangent to a first point on the connection line between the bottom surface of the axial end portion of the hybrid lateral cut and the outer surface of the tire located axially outward from it, -The second tangent to the second point on the bottom surface of the axial end portion of the hybrid transverse cut, located 2.5 mm axially inward from the first point of the connecting line, The angle formed by this is 20° or less, preferably 15° or less, and more preferably 10° or less, in a meridional section located equidistant from the leading and trailing edges of the hybrid transverse cuts connected by connecting lines.

[0086] Energy consumption associated with tire use is due not only to the rolling resistance generated by the tire but also to the aerodynamic resistance of the tire. In addition to the aspects of the present invention related to chunking described above, the inventors also understand that the arrangement of the axial end portions is relevant to features that can reduce aerodynamic resistance. The inventors have arbitrarily found that the greater the difference between the slope of the bottom surface of the axial end portions of these lateral cuts and the slope of the outer surface of the tire located axially outside the lateral cuts, the greater the disruption of airflow over the tire surface by the lateral cuts, resulting in greater aerodynamic resistance. When the slopes differ greatly, each lateral cut forms a sudden, abrupt depression in relation to the circumferential airflow. Conversely, the more similar the slope of the bottom surface of the axial end portions of these lateral cuts is to the slope of the outer surface of the tire located axially outside the lateral cuts, the less the lateral cuts disrupt airflow over the tire surface, resulting in less aerodynamic resistance. With relatively similar gradients, each lateral cut forms a recess with a smooth and gentle transition from the outer surface, which does not significantly disrupt the circumferential airflow.

[0087] Therefore, the first tangent to the first point located on the connecting line characterizes the slope of the outer surface of the tire in the meridional plane defined above. The second tangent to the second point located on the bottom surface of the axial end portion of the cut characterizes the slope of the bottom surface of the axial end portion of the transverse cut in the meridional plane defined above.

[0088] Considering a second point located 2.5 mm axially from the first point, it is guaranteed that the gradients are relatively similar at a relatively large distance from the connecting line, i.e., at the point where the depth of the lateral cut begins to become significant, and thus at the point where turbulence in airflow has the greatest impact on aerodynamic drag.

[0089] Furthermore, by considering a second point located 2.5 mm axially from the first point, it becomes possible to consider embodiments in which the bottom surface of the axial end portion of the lateral cut has a curvature oriented in the same direction as the outer surface of the tire, similar to embodiments in which the curvature changes near the connection line. Such embodiments can be envisioned in particular when the connection between the bottom surface of the lateral cut and the outer surface of the tire is formed by a fillet or a rounded section.

[0090] The axial end portion allows for drainage from the tread surface, which is the surface of the tire tread that contacts the ground. Therefore, the axial end portion is essential for obtaining good grip performance on wet ground.

[0091] In an optional, advantageous embodiment that facilitates drainage, the distance between the leading and trailing edges, measured along the connecting line, is 0.7 mm or more, preferably in the range of 0.7 mm to 6.0 mm, and more preferably in the range of 3.0 mm to 5.0 mm.

[0092] In the conventional method, a tire comprises a crown, two sidewalls, and two beads, with each sidewall connecting each bead to the crown. In the conventional method, the crown comprises a tread and crown reinforcements positioned radially inward of the tread. The tire also comprises carcass reinforcements fixed to each bead, extending radially within each sidewall and axially within the crown reinforcements radially inward.

[0093] In conventional methods, the crown reinforcement comprises at least one crown layer containing reinforcing elements. These reinforcing elements are preferably fibrous elements of fabric or metal.

[0094] In an embodiment that enables the acquisition of a tire performance mode known as a radial tire as defined by ETRTO, the carcass reinforcement comprises at least one carcass layer, which or each carcass layer comprises a carcass fibrous reinforcing element, each carcass fibrous reinforcing element extending substantially along the principal direction, which makes an angle with the circumferential direction of the tire in the range of 80° to 90° in absolute value.

[0095] The present invention will be better understood by reading the following description, which is given in conjunction with the drawings as merely a non-limiting example. [Brief explanation of the drawing]

[0096] [Figure 1] This is a top view of the tire tread according to the present invention. [Figure 2] This is a meridional cross-sectional view of the tire shown in Figure 1, parallel to the tire's axis of rotation. [Figure 3] Figure 1 is a cross-sectional view of the tire showing the arrangement of fibrous reinforcing elements inside and below the crown. [Figure 4] Figure 1 is a top view of a hybrid lateral cutaway of the tire. [Figure 5] Figure 4 is a side view of the hybrid lateral cut. [Figure 6]Figures 4 and 5 show the cross-sectional view VI-VI' related to the hybrid lateral cut. [Figure 7] Figures 4 and 5 show the cross-sectional view VII-VI related to the hybrid lateral cut. [Figure 8] Figures 4 and 5 show the cross-sectional view VIII-VIII' related to the hybrid lateral cut. [Figure 9] Figures 4 and 5 show the cross-sectional view IX-IX' related to the hybrid lateral cut. [Figure 10] This figure is similar to Figure 4, but concerns a different hybrid lateral cut in the tire shown in Figure 1. [Figure 11] This is a detailed view of the point where the hybrid lateral cut of the tire shown in Figure 1 connects to the outer surface of the tire in a meridional section parallel to the tire's axis of rotation. [Modes for carrying out the invention]

[0097] The diagrams relating to tires show reference frames X, Y, and Z corresponding to the normal axial (Y), radial (Z), and circumferential (X) directions of the tire, respectively.

[0098] In the following and above descriptions, unless otherwise specified, measurements relating to an unloaded, uninflated tire, or to a section of the tire in the meridional plane, are used.

[0099] Figures 1-3 show a tire according to the present invention, collectively denoted by reference numeral 10. The tire 10 has a substantially annular shape around a rotationally symmetric axis substantially parallel to the axial direction Y. The tire 10 is for passenger cars and has dimensions 235 / 55R19. In various figures, the tire 10 is depicted as new, i.e., unused.

[0100] Referring to Figure 2, the tire 10 comprises a crown 12, which includes a tread 14 intended to contact the ground during driving, and a crown reinforcement 16 extending circumferentially X within the crown 12. The tire 10 also includes an airtight layer 18 against expansion gas, which is intended to demarcate the internal cavity of the tire 10 once it is mounted to a mounting support, such as a rim.

[0101] The crown reinforcement 16 comprises a working reinforcement 20 and a hoop reinforcement 22. The working reinforcement 20 comprises at least one working layer, in this case two working layers, comprising a radially outer working layer 26 and a radially inner working layer 24 located radially inside it.

[0102] The hoop reinforcement 22 comprises at least one hooping layer, in this case, one hooping layer 28.

[0103] The crown reinforcement 16 is radially covered by the tread 14. In this case, the hoop reinforcement 22, in this example the hooping layer 28, is positioned radially outside the working reinforcement 20 and is therefore inserted radially between the working reinforcement 20 and the tread 14.

[0104] The tire 10 has two sidewalls 30 that extend radially inward from the crown 12. The tire 10 also has two beads 32 radially inward from the sidewalls 30. Each sidewall 30 connects each bead 32 to the crown 12.

[0105] The tire 10 includes carcass reinforcements 34 wound around bead wires 33, which are fixed to each bead 32. The carcass reinforcements 34 extend radially in each sidewall 30 and axially in the crown 12, radially inward of the crown reinforcements 16. The crown reinforcements 16 are positioned radially between the tread 14 and the carcass reinforcements 34. The carcass reinforcements 34 comprise at least one carcass layer 36.

[0106] Referring to Figure 3, each working layer 24, 26, hooping layer 28, and carcass layer 36 includes an elastomer matrix in which one or more fibrous reinforcing elements of the corresponding layer are embedded.

[0107] The hoop reinforcement 22, in this example the hooping layer 28, comprises one or more hooping fibrous reinforcing elements 280, which are spirally wound around the hooping fibrous reinforcing elements 280 in the circumferential direction of the tire 10 in the main direction D0, which forms an angle AF of 10° or less, preferably 7° or less, and more preferably 5° or less in absolute value, with respect to the circumferential direction X. In this case, AF = -5°.

[0108] The radially inner working layer 24 and the radially outer working layer 26 each comprise working fibrous reinforcing elements 240 and 260 extending in the main direction, forming opposite angles AT1 and AT2, respectively, where the angle is, in absolute value, more than 10° with respect to the circumferential direction X of the tire 10, preferably in the range of 15° to 50°, and more preferably in the range of 15° to 39°. In this case, AT1 = -26° and AT2 = +26°.

[0109] The carcass layer 36 includes carcass fibrous reinforcing elements 360 that extend in the circumferential direction X of the tire 10 and in the main direction D3 which is in the range of 60° or more in absolute value, preferably 80° to 90°, in which case AC = +90°.

[0110] Each hooping fibrous reinforcing element conventionally comprises two multifiber twisted yarns, each multifiber twisted yarn consisting of a single fiber spun yarn of aliphatic polyamide, in this case nylon, with a count equal to 140 tex, and these two multifiber twisted yarns are individually twisted spirally at 250 turns per meter and then twisted spirally together in the opposite direction at 250 turns per meter. These two multifiber twisted yarns are then spirally wound around each other. As a modified form, a hooping fibrous reinforcing element can be used, comprising one multi-fiber twisted yarn composed of aliphatic polyamide, in this case nylon monofilament, with a count equal to 140 tex, and another multi-fiber twisted yarn composed of aromatic polyamide, in this case aramid monofilament, with a count equal to 167 tex. These two multi-fiber twisted yarns are individually twisted spirally in one direction at 290 turns per meter, and then twisted spirally together in the opposite direction at 290 turns per meter. These two multi-fiber twisted yarns are then spirally wound around each other. This modified form yields AT1 = -29° and AT2 = +29°.

[0111] Each working fibrous reinforcing element 240, 260 is an assembly of two steel single fibers spirally wound at a pitch of 14 mm, with each steel single fiber having a diameter of 0.30 mm. As a variation, it is also possible to use an assembly of six steel single fibers, each having a diameter of 0.23 mm, comprising an inner layer of two single fibers spirally wound around each other in a first direction, e.g., the Z direction, at a pitch of 12.5 mm, and an outer layer of four single fibers spirally wound around the inner layer in a second direction opposite to the first direction, e.g., the S direction, at a pitch of 12.5 mm. In another variation, each working fibrous reinforcing element consists of a single steel single fiber having a diameter of 0.30 mm. More generally, the steel single fibers have diameters ranging from 0.25 mm to 0.32 mm.

[0112] Each carcass fibrous reinforcing element 360 conventionally comprises two multifiber twisted yarns, each multifiber twisted yarn composed of a single fiber spun yarn of polyester, in this case PET. These two multifiber twisted yarns are individually twisted spirally in one direction at 240 turns per meter, and then twisted spirally in the opposite direction at 240 turns per meter. Each of these multifiber twisted yarns has a count equal to 220 tex. Other variations can utilize yarns with a count equal to 144 tex and a twist equal to 420 turns per meter, or yarns with a count equal to 334 tex and a twist equal to 270 turns per meter.

[0113] Referring to Figures 1 and 2, the tread 14 has a tread surface 38 through which the tread 14 makes contact with the ground. The tread surface 38 is intended to make contact with the ground when the tire 10 is running. The tread surface is axially divided by first and second axial edges 41, 42 passing through points N located on either side of the central surface M, in which case the angle between the tangent T to the tread surface 38 passing through these points and the straight line R parallel to the axial direction Y is equal to 30°.

[0114] The tread 14 comprises an axial central portion P0 and first and second axial side portions P1 and P2, which are located on the axial sides of the axial central portion P0 with respect to the central surface M of the tire 10 and are positioned axially outward from the axial central portion P0.

[0115] Although not specific to the illustrated embodiment, the axial central portion P0 has an axial width L0 that is 50% or more, preferably 60% or more, and 80% or less, preferably 70% or less, of the axial width L of the tread surface 38 of the tire 10 when new. The first and second axial side portions P1 and P2 each have axial widths L1 and L2 that are 25% or less, preferably 20% or less, and 5% or more, preferably 10% or more, of the axial width L of the tread surface 38 of the tire 10 when new. The ratio of the axial width L0 of the central portion P0 to the axial widths L1 and L2 of the first and second axial side portions P1 and P2 each is 3.0 or more, preferably in the range of 3.0 to 5.0, and more preferably in the range of 4.0 to 4.5.

[0116] The tread 14 has N > 1 main circumferential grooves, in this example N main circumferential grooves, and includes first, second, third, and fourth main circumferential grooves denoted by reference numerals 52, 54, 56, and 58, respectively. The first and second main circumferential grooves 52 and 54 are located on both axial sides of the central surface M of the tire 10 and are the outermost axial main circumferential grooves of the tread 14.

[0117] The first axial side portion P1 and the second axial side portion P2 are positioned axially outward from the first axially outward main circumferential cut and the second axially outward main circumferential cut, respectively. The first axial side portion P1 extends axially from the first axial edge 41 of the tread surface 38 to the first main circumferential cut 52. The second axial side portion P1 extends axially from the second axial edge 42 of the tread surface 38 to the second main circumferential cut 54.

[0118] Each of the main circumferential cuts 52 to 58 is provided with a rounded chamfer. Each of the main circumferential cuts 52 to 58 has depths Ha1 and Ha2 in the range of 4.0 mm to the tread pattern height Hs, preferably in the range of 5.0 mm to the tread pattern height Hs, and more preferably in the range of 5.5 mm to the tread pattern height Hs. Each depth Ha1 and Ha2 is 50% or more of the tread pattern height Hs. In this example, for each of the main circumferential cuts 52 and 54 in the axial center P0, Ha2 = 6.5 mm, and for each of the main circumferential cuts 56 and 58, Ha2 = 6.5 mm. Therefore, each of the main circumferential cuts 52, 54, 56, and 58 has depths such that Ha1 / Hs ≥ 75%, Ha2 / Hs ≥ 75%, and more preferably Ha1 / Hs ≥ 90%, Ha2 / Hs ≥ 90%.

[0119] Each of the main circumferential cuts 52 to 58 has an axial width La1, La2, La3, and La4 that is 1.0 mm or more, preferably 5.0 mm or more, and more preferably in the range of 5.0 mm to 20.0 mm. In this example, La1 = 15.0 mm, La2 = 13.0 mm, La3 = 10.30 mm, and La4 = 7.0 mm.

[0120] The axial central portion P0 is provided with central ribs, which in this example are first, second, and third central ribs denoted by reference numerals 62, 64, and 66, respectively. Each central rib 62, 64, and 66 is positioned axially between two adjacent main circumferential cuts 52 to 58 and is axially separated by the two adjacent main circumferential cuts 52 to 58.

[0121] Each central rib 62, 64, 66 is provided with transverse cuts 74, 75, 76 having a width of 1.0 mm or less, more more strictly 0.6 mm or less, and in this example equal to 0.4 mm. Each transverse cut 74, 75, 76 has a depth Hb equal to 3.5 mm.

[0122] Each of the first and second axial sides P1 and P2 is provided with first and second lateral ribs denoted by reference numerals 68 and 70, respectively, and in this example, is composed of the first and second lateral ribs 68 and 70, respectively.

[0123] The tread 14 is provided with lateral cuts 77, 78 that are at least partially made on at least one of the first and second axial sides P1, P2, in this example at least partially made on each of the first and second axial sides P1, P2. These lateral cuts 77, 78 are called hybrid for the reasons stated above. At least 50%, preferably at least 75%, more preferably at least 90%, and in this example 100%, of the lateral cuts that are at least partially made on at least one of the first and second axial sides P1, P2, in this example at least partially made on each of the first and second axial sides P1, P2 are hybrid lateral cuts 77, 78.

[0124] Here, we will explain the hybrid lateral cutouts 78 with reference to Figures 4 to 9. When the tire is mounted on the wheel, these are hybrid lateral cutouts located on the outside of the wheel, and therefore on the outside of the vehicle.

[0125] Each hybrid lateral cut 78 is provided with a chamfer 79 and is circumferentially separated by a leading edge 85 and a trailing edge 87. Each hybrid lateral cut 78 comprises a so-called narrow axial inner portion 80, a so-called wide axial outer portion 82, and an axial end portion 83 made on the axial outer side of the second axial side portion P2 and communicating with the wide axial outer portion 82. Each hybrid lateral cut 78 has a portion of each hybrid lateral cut with a curve length Lot made on the second axial side portion P2. In this example, Lot = 45 mm. The portions 80, 82, and 83 are adjacent.

[0126] The narrow axial inner portion 80 is the innermost axial portion of the hybrid lateral cut 78 in the second axial side portion P2. The narrow axial inner portion 80 extends from the axial inner end 84 to the axial outer end 86. The narrow axial inner portion 80 appears within the adjacent main circumferential cut 54. The narrow axial inner portion has a curve length Loi that is at least 20% and at most 75% of the curve length Lot. In this example, Loi = 23 mm, which is 51% of the curve length Lot.

[0127] The wide axial outer portion 82 communicates with the narrow axial inner portion 80 and is positioned axially outward of the narrow axial inner portion 80. The wide axial outer portion 82 is the outermost axial portion of the hybrid lateral cut 78 in the second axial side portion P2. The wide axial outer portion 82 extends from the axial inner end 88 (which coincides with the axial outer end 86 in this example) to the axial outer end 90. The wide axial outer portion has a curve length Loe. In this example, Loe = 22 mm.

[0128] The axial end portion 83 extends from the axial inner end 91 (which in this case coincides with the axial outer end 90) to the axial outer end. This axial outer portion 93 is hybrid This is realized by a connecting line 92 between the bottom surface 94 of the axial end portion 83 of the lateral cut 78 and the outer surface 96 of the tire 10 located axially outward from it.

[0129] Note that in Figure 4, for clarity, the curve length is not shown as the length measured along a curve that passes equidistant from the leading edge 85 and trailing edge 87 between both ends of the hybrid lateral cut 78 or between each section 80, 82. However, as mentioned above, they must be measured along a curve that passes equidistant from the leading edge 85 and trailing edge 87 between both ends of the hybrid lateral cut 78 or between each section 80, 82.

[0130] As shown in Figures 6 to 9, the narrow-axis inner portion 80 has a bottom surface 94 of a hybrid lateral cut, where the width Lai at the bottom surface 94 of the cut is in the range of 0.2 mm to 0.6 mm, preferably in the range of 0.2 mm to 0.5 mm, and in this example Lai = 0.4 mm. The narrow-axis inner portion 80 has a depth in the range of 2.0 mm to 5.5 mm, preferably in the range of 3.0 mm to 5.0 mm, and in this example has a depth equal to 4.4 mm.

[0131] The wide axial outer portion has a width Lae at the bottom surface 94 of the notch ranging from 0.7 mm to 5.0 mm, preferably from 1.0 mm to 5.0 mm, and more preferably from 2.0 mm to 4.5 mm. As defined above, the width Lae is the maximum distance between the two main sides 97, 98 of the wide axial outer portion 82 at the bottom surface 94 of the notch, and is therefore measured at the end 90 in this example. As seen in Figure 1, the wide axial outer portion 82 has different width Laes randomly distributed to suppress whining noise. In this example, the different width Laes used are equal to 3.1 mm, 3.7 mm, and 4.1 mm. The wide axial outer portion 82 has a depth ranging from 2.0 mm to 5.5 mm, preferably from 3.0 mm to 5.0 mm, and in this example, a depth equal to 4.6 mm.

[0132] As shown in Figures 4, 5, 8, and 9, the wide axial outer portion has two main sides, a front 97 and a rear 98, which connect to the bottom 94 of the hybrid lateral cut 78 with a fillet 99.

[0133] Within the axial end portion 83, the distance dr between the leading edge 85 and the trailing edge 87, measured along the connecting line 92, is 0.7 mm or more, preferably in the range of 0.7 mm to 6.0 mm, and more preferably in the range of 3.0 mm to 5.0 mm. In this example, the different values ​​of dr are equal to 3.4 mm, 3.6 mm, and 4.7 mm.

[0134] Returning to Figures 4 and 5, each hybrid lateral cut 78 comprises a so-called inclined axial inner portion 100 made on the second axial side P2, and a so-called linear axial outer portion 102 positioned axially outward of the inclined axial inner portion 100 and also made on the second axial side P2. Portions 100 and 102 are adjacent to each other.

[0135] The inclined axial inner portion 100 forms an average angle A with respect to the axial direction Y of 15° or more, preferably 20° or more, and in this example, A = 23°. The inclined axial inner portion 100 is the innermost axial portion of the hybrid lateral cut 78 in the second axial side portion P2.

[0136] The linear axial outer portion 102 forms an average angle B with respect to the axial direction Y, which is strictly smaller than the average angle of the inclined axial inner portion 100. The average angle of the linear axial outer portion 102 is strictly 25° or less, preferably 20° or less, more preferably 15° or less, and in this case equals 8°. The linear axial outer portion 102 is the outermost axial portion of the hybrid lateral cut 78 in the second axial side portion P2.

[0137] In this case, the narrow-axis inner portion 80 includes at least a portion of the inclined-axis inner portion 100, and in this example, includes the entire inclined-axis inner portion 100 together with the first portion of the linear-axis outer portion 102 up to the common ends 86, 88 of portions 80, 82. The wide-axis outer portion 82 includes the second portion of the linear-axis outer portion from the ends 86, 88 up to the second axial edge 42 of the tread surface 38.

[0138] Figure 10 shows one of the hybrid lateral cuts 77. For simplicity, Figure 10 uses the same reference numerals for elements as those shown in Figure 4, which illustrates the hybrid lateral cut 78.

[0139] Unlike the hybrid lateral cut 78, each hybrid lateral cut 77 has Lot=38mm, Loi=14mm, and Loe=24mm. Furthermore, angles A and B are A=25° and B=8°.

[0140] Returning to Figure 2, the tire 10 comprises a tread layer 110 and a support layer 112 for the tread layer 110. The support layer 112 is positioned radially inward of the tread layer 110. The tread layer 110 and the support layer 112 are adjacent at an interface 114. The support layer 112 has very low rolling resistance, characterized by a dynamic loss tanDMAX23 equal to 0.095 when measured in accordance with ASTM D-5992-96 at a temperature of 23° and a frequency of 10 Hz.

[0141] Furthermore, in the meridional section of Figure 2, a regulated wear trajectory 116 is defined that is parallel to the tread surface 38 of the tire 10 and passes through the radially outer surface 118 of the regulated wear indicator 120. In the illustrated embodiment, at least a portion 122 of the interface 114 that is radially aligned with the narrow-axis inner portion 80 is located radially outward from at least a portion 124 of the interface 114 that is radially aligned with the wide-axis inner portion 82.

[0142] The bottom surface 94 of the hybrid lateral cut 77 is also shown. The entire bottom surface 94 of each hybrid lateral cut 77, 78 is located radially outward from the interface 114 between the tread layer 110 and the support layer 112. Furthermore, at least a portion 126 of the bottom surface 94 of the narrow-axis inner portion 80 is located at a radial distance di that is strictly greater than the radial distance de from the interface 114 where at least a portion 128 of the bottom surface 94 of the wide-axis outer portion 82 is located.

[0143] In the illustrated embodiment, at least 60%, preferably at least 75%, in this case 100%, of the curve length Loi of the narrow-axis inner portion 80 is located at a radial distance di that is strictly greater than the average radial distance dem from the interface 114 where the bottom surface 94 of the wide-axis outer portion 82 is located.

[0144] More specifically, the bottom surface 94 of the inner portion 80 in the narrow axis direction is positioned at an average radial distance dim that is strictly greater than the average radial distance dem from the interface 114 where the bottom surface 94 of the outer portion 82 in the wide axis direction is positioned. Hiro Axial axis outside side part 82 The average radial distance dim between the bottom surface and the interface 114 is in the range of 0.3 mm to 1.0 mm, preferably 0.4 mm to 0.9 mm. narrow Axial axis Inside side part 80 The average radial distance dem between the bottom surface 94 and the interface 114 is in the range of 0.5 mm to 1.5 mm, preferably 0.6 mm to 1.2 mm. In this case, d e m = 0.5 mm, d i m = 1.0 mm.

[0145] Figure 11 shows a view of the meridional section XII-XII' of Figure 10, located equidistant from the leading edge 85 and trailing edge 87 connected by the connecting line 92. The bottom surface 94 of the axial end portion 83 includes a fillet 130 that forms the confluence point of the bottom surface 94 and the connecting line 92. Figure 11 shows a first tangent T3 to a first point P3 and a second tangent T4 to a second point P4. The first point P3 is a point in the plane XII-XII' and is a point on the connecting line 92. The second point P4 is a point on the bottom surface 94 of the axial end portion 83 of the hybrid transverse cut 77, located 2.5 mm axially inward from the first point P3 on the connecting line 92. In Figure 11, this distance of 2.5 mm is shown by a dashed circle with a diameter of 5.0 mm, and its center is the first point P3. The angle K between the first tangent T3 and the second tangent T4 is 20° or less, preferably 15° or less, and in this example equal to 11°. In other, more advantageous embodiments, the angle K can be 10° or less.

[0146] The present invention is not limited to the embodiments described above. [Explanation of symbols]

[0147] 10 tires 12 Crown 14 tread 16 Crown reinforcement 18 Airtight layer 20 Working reinforcement 22 Hoop reinforcement 24 Radial Inner Working Layer 26 Radial Outer Working Layer 28 Hooping Layer 30 Sidewall 32 Bead 33 Bead wire 34 Carcass reinforcement 36 Carcass layer 38 Tread surface 41 First axial edge 52 First main circumferential cut 56 Thirdly, main circumferential cutting 62 First central rib 64 Second central rib 68 First lateral rib 80 Narrow axial inner part 82 Wide axial outer part 94 Bottom 110 tread layers 112 Support layer 114 Interface 116 Regulated wear trajectory 118 Radial outer surface of regulated wear indicator 120 Regulatory wear indicator 122 At least a portion of the interface 124 At least a portion of the interface 126 At least a portion of the bottom surface of the inner part in the narrow axis direction 128 At least a portion of the bottom surface of the wide axial outer portion de Radial distance from the interface di Radial distance from the interface H tire section height Ha1 Depth of cut in the main circumferential direction Ha2 Depth of cut in the main circumferential direction Hs Tread Pattern Height L Tread surface axial width L0 Axial width of the central part in the axial direction L1 Axial width of the first axial side L2 Axial width of the second axial side La1 Axial width of the main circumferential cut La2 Axial width of the main circumferential cutting M Tire center surface N: A point that defines the axial edge of the tread surface. P1 First axial side A straight line parallel to the axis passing through point N. T is the tangent to the tread surface passing through point N. X Circumferential direction of the tire Y-shaped tire axial direction Z Tire Radial Direction

Claims

1. A passenger car tire (10) having a tread (14) intended to contact the ground via a tread surface (38) when driving, wherein the tread (14) is A main circumferential cut (52, 54, 56, 58) having a depth (Ha1, Ha2) of 50% or more of the tread pattern height (Hs), and comprising first and second axially outer main circumferential cuts (52, 54) arranged on both axial sides of the central surface (M) of the tire (10), wherein the first and second axially outer main circumferential cuts (52, 54) are the outermost axial main circumferential cuts of the tread (14), A first axial side portion (P1) is positioned axially outward of the first axial outward main circumferential cut (52) and extends axially from the first axial edge (41) of the tread surface (38) to the first axial outward main circumferential cut (52), A second axial side portion (P2) is positioned axially outward of the second axial outward main circumferential cut (54) and extends axially from the second axial edge (42) of the tread surface (38) to the second axial outward main circumferential cut (54), The tire (10) comprises a tread layer (110) and a support layer (112) for the tread layer (110), wherein the support layer (112) is positioned radially inward of the tread layer (110). The tread (14) is provided with so-called hybrid lateral cuts (77, 78) that are at least partially made on at least one of the first and second axial sides (P1, P2), and each of the hybrid lateral cuts (77, 78) is A so-called narrow axial inner portion (80) having a width (Lai) in the range of 0.2 mm to 0.6 mm at the bottom surface (94) of the cut, wherein the narrow axial inner portion (80) is the innermost axial portion of the hybrid lateral cut (77, 78) in at least one of the first and second axial side portions (P1, P2), The bottom surface (94) of the cut has a width (Lae) in the range of 0.7 mm to 5.0 mm, communicates with the narrow-axis inner portion (80), and is positioned axially outward of the narrow-axis inner portion (80), wherein the wide-axis outer portion (82) is the outermost axial portion of the hybrid lateral cut (77, 78) in at least one of the first and second axial sides (P1, P2), Equipped with, Each of the aforementioned hybrid lateral cuts (77, 78) has a hybrid lateral cut bottom surface (94), and the entire bottom surface (94) of each of the aforementioned hybrid lateral cuts (77, 78) is located radially outward from the interface (114) between the tread layer (10) and the support layer (112). At least a portion (126) of the bottom surface (94) of the inner portion (80) in the narrow axis direction is positioned at a radial distance (di) that is strictly greater than the radial distance (de) from the interface (114) to which at least a portion (128) of the outer portion (82) in the wide axis direction is positioned. A tire (10) characterized by the following features.

2. The tire (10) according to claim 1, wherein at least 60% of the curve length (Loi) of the inner portion (80) in the narrow axis direction is positioned at a radial distance (di) that is strictly greater than the mean radial distance (dem) from the interface (114) where the bottom surface (94) of the outer portion (82) in the wide axis direction is positioned.

3. The tire (10) according to claim 1 or 2, wherein the bottom surface (94) of the inner portion (80) in the narrow axis direction is positioned at an average radial distance (dim) that is strictly greater than the average radial distance (dem) from the interface (114) where the bottom surface (94) of the outer portion (82) in the wide axis direction is positioned.

4. The tire (10) according to claim 1, wherein at least a portion (122) of the interface (114) arranged radially alongside the narrow-axis inner portion (80) is located radially outward of at least a portion (124) of the interface (114) arranged radially alongside the wide-axis outer portion (82).

5. The tire (10) according to claim 1, wherein the tread (14) is provided with hybrid lateral cuts (77, 78) partially made in each of the first and second axial sides (P1, P2).

6. The tire (10) according to claim 1, wherein at least 50% of the lateral cuts made at least partially on at least one of the first and second axial sides (P1, P2) are hybrid lateral cuts (77, 78).

7. The tire (10) according to claim 1, wherein the narrow axial inner portion (80) has a curve length (Loi) equal to at least 20% and up to 75% of the curve length (Lot) of each portion of the hybrid lateral cut (77, 78) made in at least one of the first and second axial side portions (P1, P2).

8. The tire (10) according to claim 1, wherein the width (Lai) of the inner portion (80) in the narrow axis direction at the bottom surface (94) of the notch is in the range of 0.2 mm to 0.5 mm.

9. The tire (10) according to claim 1, wherein the width (Lae) of the wide axial outer portion (82) at the bottom surface (94) of the notch is in the range of 1.0 mm to 5.0 mm.

10. Each of the aforementioned hybrid lateral cuts (77, 78) is, A so-called inclined axial inner portion (100) is made on at least one of the first and second axial side portions (P1, P2) and forms an average angle of 15° or more with respect to the axial direction (Y), and is the inclined axial inner portion (100) which is the innermost axial portion of the hybrid lateral cut (77, 78) in at least one of the first and second axial side portions (P1, P2), A so-called linear axial outer portion (102) is formed on at least one of the first and second axial sides (P1, P2), and the axial direction (Y) has an average angle (B) that is strictly smaller than the average angle (A) of the inclined axial inner portion (100), and is positioned axially outward of the inclined axial inner portion (100), and the linear axial outer portion (102) is the outermost axial portion of the hybrid lateral cut (77, 78) in at least one of the first and second axial sides (P1, P2), A tire (10) according to claim 1, comprising the features described above.

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