Tire comprising mixed transverse cuts

Abstract

The tyre (10) comprises so-called hybrid transverse cuts provided in the first and second axial side portions (P1, P2) and comprising: - a narrow axial inner portion (80) having a width at the cut bottom (94) ranging from 0.2 mm to 0.6 mm, - a wide axial outer portion (82) having a width at the cut bottom (94) ranging from 0.7 mm to 5.0 mm. Each hybrid transverse cut has a bottom (94), all the bottoms (94) being arranged radially outside the interface (114) between the tread layer (110) and the support layer (112). The radial distance (di) of the bottom (94) of the narrow axial inner portion (80) from the interface (114) is strictly greater than the radial distance (de) of the bottom (94) of the wide axial outer portion (82) from the interface (114).

Description

Technical Field

[0001] This invention relates to a tire for passenger vehicles. A tire is defined as an outer tire designed to form a cavity through cooperation with a supporting element (e.g., a rim), the cavity being pressurized to pressures above atmospheric pressure. The tire according to the invention has a structure exhibiting a generally toroidal surface shape that is rotationally symmetrical about the tire's main axis. Background Technology

[0002] A tire for passenger vehicles is known in the prior art, marketed under the MICHELIN® brand and belonging to the PRIMACY 4® series. This tire includes a tread designed to contact the ground via a tread surface supported by tread layers during tire travel. The tire also includes a support layer, also known as a sub-layer, arranged radially inside the tread layers.

[0003] The tread includes a main circumferential cut, the depth of which is greater than or equal to 50% of the tread pattern height, and includes a first axially outward main circumferential cut and a second axially outward main circumferential cut located on both sides of the tire's midplane. The first axially outward main circumferential cut and the second axially outward main circumferential cut are the outermost main circumferential cuts in the tread's axial direction.

[0004] The tread includes ribs, which are axially arranged between two adjacent main circumferential cuts and defined axially by the two adjacent main circumferential cuts. Specifically, the ribs include a first axial side portion and a second axial side portion, which are axially arranged outside the first and second axially outer main circumferential cuts, respectively.

[0005] The first axial side portion and the second axial side portion each include a transverse cut, the transverse cut including a groove, the groove having a width of 0.4 mm at the bottom of the cut over the entire curve length of each groove.

[0006] It has been noted that, in some cases, chipping occurs on the tread portion of this tire in both the first and second axial sides.

[0007] This type of tire can also be identified from US9085201, US10864775, US2013112325, and US10449807.

[0008] The present invention aims to reduce or even eliminate the presence of such chipping without excessively affecting rolling resistance performance and grip performance on wet surfaces. Summary of the Invention

[0009] Therefore, the present invention relates to a tire for a passenger vehicle, the tire including a tread, the tread being intended to contact the ground via a tread surface during tire travel, the tread comprising:

[0010] - A main circumferential cut, the depth of which is greater than or equal to 50% of the tread height and includes a first axially outer main circumferential cut and a second axially outer main circumferential cut arranged axially on both sides of the tire's midplane, wherein the first axially outer main circumferential cut and the second axially outer main circumferential cut are the outermost main circumferential cuts in the tread axially.

[0011] - A first axial side portion, which is axially arranged outside the first axial outer main circumferential cut and extends axially from the first axial edge of the tread surface to the first axial outer main circumferential cut.

[0012] - The second axial side portion is arranged axially outside the second axial outer main circumferential cut and extends axially from the second axial edge of the tread surface to the second axial outer main circumferential cut.

[0013] The tire includes a tread layer and a support layer for the tread layer, the support layer being arranged radially inside the tread layer.

[0014] The tread includes so-called mixed lateral cuts, which are formed at least partially in at least one of a first axial-side portion and a second axial-side portion, each mixed lateral cut including:

[0015] - The so-called narrow axial inner portion, the width of which at the bottom of the cut ranges from 0.2 mm to 0.6 mm, is the innermost axial portion of a mixed transverse cut of at least one of the first axial side portion and the second axial side portion.

[0016] - The so-called wide axial outer portion, which has a width ranging from 0.7 mm to 5.0 mm at the bottom of the cut, communicates with the narrow axial inner portion and is arranged axially outside the narrow axial inner portion. The wide axial outer portion is the outermost axial portion of a mixed transverse cut of at least one of the first axial side portion and the second axial side portion.

[0017] Each mixed lateral cut has a mixed lateral cut bottom, and the entire bottom of each mixed lateral cut is arranged radially on the outside of the interface between the tread layer and the support layer.

[0018] The radial distance between at least a portion of the bottom of the narrow axial inner portion and the interface is strictly greater than the radial distance between at least a portion of the bottom of the wide axial outer portion and the interface.

[0019] The inventors of this invention believe that tire chipping occurs because, during the tire molding process that forms sipes in the axial side portion, the uncured elastomeric composition of the axial side portion or each axial side portion is penetrated by the molding element (in this case, the sipe piece used to mold each sipe). The inventors believe that the narrower the width of the sipe bottom and the deeper the sipe, the greater this penetration. The finer the sipe piece, the more it can cut into the elastomeric composition of the axial side portion or each axial side portion. Furthermore, if the sipe piece penetrates deeply into the elastomeric composition, it can penetrate the interface between the tread layer and the support layer, thereby having the effect of causing the support layer to move radially outward. When the tire wears severely, this radial outward movement of the support layer, particularly in the axially outer portion of the axial side portion, causes the interface to appear on the tread surface. Since this interface is not designed to contact the ground where the tire travels, it deteriorates rapidly, causing the aforementioned chipping.

[0020] To address this problem, the inventors of this invention designed a hybrid lateral cut, the bottom of which is radially positioned outside the interface between the tread layer and the support layer to prevent the hybrid lateral cut from penetrating the interface. In other words, the bottom of each hybrid lateral cut will not cut into the interface.

[0021] First, in this invention, the portion of the tread most likely to experience chipping includes the wide, outward portion of the mixed lateral cuts. The inventors of this invention noted that, unlike the molding of sipes, the molding of lateral cuts with a width greater than or equal to 0.7 mm does not cause the interface to move radially outward due to penetration, but rather radially inward due to molding pressure. This reduces the appearance of the interface on the tire surface, thereby reducing chipping.

[0022] Secondly, compared to the bottom portion of the wide-axis outer section, the bottom portion of the narrow-axis inner section is further radially from the interface, reducing the likelihood that the interface portion aligned with the narrow-axis inner section will be used to mold elements that penetrate the narrow-axis inner section. This reduces the risk of chipping.

[0023] The radial distance between the bottom of each section and the interface is a distance measured in the radial direction. The distance from a section is the distance measured for each point of that section. Therefore, if the radial distance between all points at the bottom of the narrow axial inner section is strictly greater than the radial distance between all points at the bottom of the wide axial outer section, then the bottom of the narrow axial inner section will be radially further away from the interface than the bottom of the wide axial outer section.

[0024] Furthermore, the hybrid lateral cut of the tire according to the invention maintains both rolling resistance and grip performance on wet surfaces. The lateral cut is referred to as a hybrid lateral cut because it consists of two parts (a narrow part and a wide part).

[0025] Since the narrow portion of each mixed lateral cut is the innermost axial part of the mixed lateral cut in the axial side portion, it is located in the corresponding portion of the tread with a relatively large tread height. The greater the tread height, the greater the Poisson effect and the greater the reduction in rolling resistance due to the presence of the cut. Because the width of the narrow inner axial portion is relatively small, the Poisson effect is limited by the contact between the two main sides of the narrow inner axial portion when the tire passes over the contact patch, thus reducing rolling resistance. Since the wide outer axial portion is the outermost axial part of the mixed lateral cut in the axial side portion, it is located in the following portion of the tread where the tread height is necessarily smaller due to the curvature of the tire. Therefore, the Poisson effect is lower here, and the width of the wide outer axial portion has almost no adverse effect on rolling resistance.

[0026] Furthermore, the wide axially outward portion of each hybrid lateral cut can effectively drain water, and due to the relatively large width at the bottom of the cut, drainage is improved under all conditions compared to tires of the prior art.

[0027] The narrow axial inner portion can be likened to a sipe, while the wide axial outer portion can be likened to a groove (provided it is wide enough). The distance between the main sides of the sipe is suitable to allow the main sides defining the sipe to at least partially contact each other in the contact patch, especially when the tire is brand new and under normal driving conditions, which specifically includes the fact that the tire is under its nominal load and nominal pressure. The distance between the main sides of the groove ensures that these main sides do not contact each other under normal driving conditions, which specifically includes the fact that the tire is under its nominal load and nominal pressure.

[0028] Typically, the tread surface is defined axially by a first axial edge and a second axial edge. The first and second axial edges of the tread surface are determined according to the 2019 standards of the European Tire and Rim Technology Organization (ETRTO) on a tire mounted on a nominal rim and inflated to nominal pressure. The first and second axial edges of the tread surface are located on either side of the tire's midplane and are formed by lines substantially parallel to the tire's circumferential direction. If there is a clear boundary between the tread surface and the rest of the tire, the first and second axial edges of the tread surface can be easily determined. If the tread surface is continuous with the outer surface of the tire sidewall, then within each meridional section, the first and second axial edges each pass through a point where the angle between the tangent to the tread surface and the straight line parallel to the axial direction passing through that point is equal to 30°. When there are multiple points with an absolute angle of 30° within a meridional section, the outermost radial point is used.

[0029] When tire wear is less than a specified wear threshold, the support layer of the tire according to the invention is designed to not contact the ground during tire operation; for example, the wear threshold is indicated on the tire by a specified wear indicator. In other words, the interface between the tread layer and the support layer is radially arranged over at least 90% (preferably 100%) of its curve length, inside the surface parallel to the tread surface of a new tire and passing through the outermost radial point of the specified wear indicator. This support layer is in direct contact with the tread layer. The support layer is radially arranged inside the tread layer over its entire axial width. The support layer is not a tread layer located radially inside the outermost radial tread layer.

[0030] The tread layer may include a single elastomer composition or multiple elastomer compositions to optimize other performance criteria of the tire, particularly the radial and axial distributions, as described in WO2015032601, WO2012175444, EP3508354, EP2594413 and WO2009124816.

[0031] Of course, the first axial portion and the second axial portion of the tread, or each of them, may include other lateral cuts that do not have mixed lateral cut features, as well as circumferential cuts with a depth strictly less than 50% of the tread height.

[0032] On a brand new tire, the tread depth (or tread portion) is the maximum radial distance between the bottom of the tread (or tread portion) and the projection of the bottom of the tread onto the ground when the tire is in motion. The maximum tread depth is called the tread height.

[0033] A cut (or cut portion) on the tread surface has two main characteristic dimensions: width and curve length, wherein the curve length is at least twice the width. Therefore, a cut (or cut portion) is defined by at least two principal lateral surfaces that determine its curve length and are connected by the bottom, and the distance between these two principal lateral surfaces is not zero, which is called the cut (or cut portion) width.

[0034] On a brand-new tire, the width of the cut (or cut portion) is the maximum distance between the two main sidewalls. This maximum distance is measured by default at a radial point coinciding with the tread surface when the cut (or cut portion) has no chamfer, and by default at the outermost radial point of the cut (or cut portion) and the radially inner side of the chamfer when the cut (or cut portion) has a chamfer. The width is measured substantially perpendicular to the main sidewalls. If a width other than the default width is specified, such as the width at a specific point, the width is equal to the distance between the two main sidewalls at that specific point at the bottom of the cut (or cut portion). In the case of this invention, regardless of whether the mixed lateral cut is chamfered, the width at the bottom of the cut is equal to the distance between the two main sidewalls measured at the bottom of the corresponding portion of the cut.

[0035] The incision (or incision portion) can be transverse or circumferential.

[0036] The lateral cut must extend along an average direction that forms an angle strictly greater than 30°, preferably greater than or equal to 45°, with the tire's circumferential direction; that is, an angle less than or equal to 60°, preferably strictly less than 45°, with the tire's axial direction. The average direction is the shortest curve connecting the two ends of the cut and parallel to the tread surface. The lateral cut (or cut portion) is continuous, i.e., not interrupted by tread blocks or another cut, such that the two principal sides determining its length are not interrupted along the length of the lateral cut (or cut portion). The lateral cut can also be discontinuous, i.e., interrupted by one or more tread blocks and / or one or more cuts, such that the two principal sides determining its length are interrupted by one or more tread blocks and / or one or more cuts.

[0037] A circumferential cut satisfies the condition that the cut (or cut portion) extends along an average direction, which forms an angle of less than or equal to 30°, preferably less than or equal to 10°, with the circumferential direction of the tire; that is, it forms an angle of strictly greater than 60°, preferably strictly greater than 80°, with the axial direction of the tire. The average direction is the shortest curve connecting the two ends of the cut and parallel to the tread surface. In the case of continuous circumferential cuts, the two ends overlap each other and are joined by a curve forming a full circumference around the tire. A circumferential cut can be continuous, i.e., not interrupted by a tread block or another cut, such that the two principal sides determining its length are not interrupted on a full circumference around the tire. A circumferential cut can also be discontinuous, i.e., interrupted by one or more tread blocks and / or one or more cuts, such that the two principal sides determining its length are interrupted on a full circumference around the tire by one or more tread blocks and / or one or more cuts.

[0038] In the case of a transverse cut or a transverse cut portion, the side refers to the leading edge and the trailing edge, and the leading edge and the trailing edge are each provided with a leading edge and a trailing edge, respectively. For a given circumference, the leading edge is the edge that enters the ground plane before the trailing edge.

[0039] In embodiments that can optionally improve braking performance on dry surfaces, the mixing transverse cut, or each mixing transverse cut, is provided with a chamfer. The chamfer on the mixing transverse cut can be a straight chamfer or a rounded chamfer. A straight chamfer is formed by a plane that is inclined relative to the leading and trailing edge surfaces and extends circumferentially to define the leading or trailing edge of the mixing transverse cut. A rounded chamfer is formed by a curved surface that merges tangentially with the leading or trailing edge surface to which it extends. The chamfer on the mixing transverse cut is characterized in that its height and width are respectively equal to the radial distance between the common point of the leading or trailing edge surface to which the chamfer extends and the circumferential distance between the leading or trailing edge surface defining the leading or trailing edge of the mixing transverse cut, and the distance in a direction perpendicular to the leading or trailing edge surface.

[0040] In some embodiments that can optionally improve braking performance on wet surfaces, at least one main circumferential cut is provided with a chamfer. The chamfer on the circumferential cut can be a straight chamfer or a rounded chamfer. A straight chamfer is formed by a plane that is inclined relative to the axial inner and axial outer surfaces and extends to the axial inner or axial outer edge defining the circumferential cut along the axial direction. A rounded chamfer is formed by a surface that merges tangentially with the axial inner or axial outer surface to which it extends. The chamfer on the circumferential cut is characterized in that its height and width are respectively equal to the radial distance and axial distance between the common point of the axial inner or axial outer surface to which the chamfer extends and the axial inner or axial outer edge defining the circumferential cut along the axial direction.

[0041] The tire according to the invention has a generally toroidal shape about an axis of rotation substantially coincident with the axis of rotation of the tire. This axis of rotation defines three directions commonly used by those skilled in the art: axial direction, circumferential direction, and radial direction.

[0042] The axial direction refers to the direction that is substantially parallel to the axis of rotation of the tire (i.e., the axis of rotation of the tire).

[0043] The circumferential direction refers to the direction that is essentially perpendicular to both the axial direction and the tire radius (in other words, tangent to the circle centered on the tire's axis of rotation).

[0044] Radial direction refers to the direction along the tire radius, that is, any direction that intersects the tire's axis of rotation and is substantially perpendicular to that axis.

[0045] The tire's midplane (denoted by M) refers to a plane perpendicular to the tire's axis of rotation, located axially in the center between the two bead sections and passing through the axial center of the crown reinforcement.

[0046] The equatorial circumferential plane of a tire (denoted by E) refers to the plane that passes through the tire's equator and is perpendicular to the midplane and radial direction in the meridional section. In the meridional section (a plane perpendicular to the circumferential direction and parallel to the radial and axial directions), the tire's equator is the axis parallel to the tire's axis of rotation and equidistant between the outermost radial point of the tread intended to contact the ground and the innermost radial point of the tire intended to contact a support (such as the rim), the distance between which is equal to H.

[0047] The meridional plane refers to a plane that is parallel to the axis of rotation of the tire, contains the axis of rotation, and is perpendicular to the circumferential direction.

[0048] Radial location (inner / inner side) and radial location (outer / outer side) refer to being closer to and further away from the tire's axis of rotation, respectively. Axial location (inner / inner side) and axial location (outer / outer side) refer to being closer to and further away from the tire's midplane, respectively.

[0049] The bead refers to the portion of a tire designed to attach the tire to a mounting support (such as a wheel, including a rim). Therefore, each bead is specifically designed to contact the flange of the rim for attachment.

[0050] Any range of values ​​expressed as “between a and b” represents a range of values ​​from greater than a to less than b (i.e., excluding endpoints a and b), while any range of values ​​expressed as “between a and b” means a range of values ​​from a to b (i.e., including the strict endpoints a and b).

[0051] In a preferred embodiment of the invention, the tire is intended for use in passenger vehicles as defined by the European Tire and Rim Technology Organization (ETRTO) standard of 2019. Such a tire has a cross-section in its meridional section characterized by a ratio, expressed as a percentage, of at least 90, preferably at least 80, more preferably at least 70 and at least 30, preferably at least 40, according to the 2019 ETRTO standard; and a nominal cross-section width S of at least 115 mm, preferably at least 155 mm, more preferably at least 175 mm and at most 385 mm, preferably at most 315 mm, more preferably at most 285 mm, and even more preferably at most 255 mm. Furthermore, the diameter D at the rim flange defines the diameter of the rim on which the tire is mounted, which is at least 12 inches, preferably at least 16 inches and at most 24 inches, preferably at most 20 inches.

[0052] Optionally and preferably, the depth of each main circumferential cut is greater than or equal to 75% of the tread pattern height, more preferably greater than or equal to 90% of the tread pattern height.

[0053] In an implementation scheme where the main circumferential cuts are relatively deep and suitable for passenger vehicle tires, the depth of each main circumferential cut ranges from 4.0 mm to the tread height, preferably from 5.0 mm to the tread height, and more preferably from 5.5 mm to the tread height.

[0054] In an embodiment where the main circumferential cut is a relatively wide main circumferential groove and is suitable for passenger vehicle tires, the axial width of each main circumferential cut is greater than or equal to 1.0 mm, preferably greater than or equal to 5.0 mm, and more preferably ranging from 5.0 mm to 20.0 mm.

[0055] In an optional embodiment, it is also conceivable that at least one of the first axial side portion and the second axial side portion includes at least one additional circumferential cut, the depth of which is strictly less than 50% of the tread height, preferably less than or equal to 30% of the tread height, and more preferably ranging from 10% to 30% of the tread height.

[0056] In some implementations, the narrow axial inner portion and the wide axial outer portion are adjacent. Adjacent means that no other portion is inserted between the narrow axial inner portion and the wide axial outer portion along the axial direction.

[0057] In a preferred embodiment, each main side of the mixed transverse cut is connected to the bottom of the mixed transverse cut by a fillet. The presence of the fillet reduces crack formation, which is a precursor to chipping. This reduces the occurrence of chipping. The larger the radius of curvature of each fillet, the more significant the effect of reducing crack formation.

[0058] In an advantageous but optional embodiment that can further reduce chipping, at least 60% (preferably at least 75%) of the curve length of the narrow axial inner portion is radially distanced from the interface to a distance that is strictly greater than the average radial distance at the bottom of the wide axial outer portion.

[0059] The longer the curve length of the narrow axial inner portion, which maintains a sufficient radial distance from the interface, the lower the risk of chipping. However, the bottom of the narrow axial inner portion can be very close to the interface locally while still reducing the risk of chipping.

[0060] The curve length of a portion of a transverse cut or transverse cut (mixed cut or other cut) is the length measured along a curve that passes equidistantly from the front and rear edges between the two ends of the transverse cut or the portion.

[0061] In an advantageous but optional embodiment that minimizes chipping as much as possible, the average radial distance between the bottom of the narrow axial inner portion and the interface is strictly greater than the average radial distance between the bottom of the wide axial outer portion and the interface.

[0062] The average radial distance refers to the average radial distance between the interface and the bottom of the portion, measured along the portion.

[0063] In some implementations where the bottom of the narrow axial inner portion is closer to the interface locally than the wide axial outer portion, the risk of chipping can still be reduced.

[0064] In an optional but preferred embodiment, the average radial distance between the bottom of the wide axially outward portion and the interface ranges from 0.3 mm to 1.0 mm, preferably from 0.4 mm to 0.9 mm.

[0065] In an optional but preferred embodiment, the average radial distance between the bottom of the narrow axial inner portion and the interface ranges from 0.5 mm to 1.5 mm, preferably from 0.6 mm to 1.2 mm.

[0066] In an optional embodiment, at least a portion of the interface arranged radially aligned with the inner portion of the narrow axis is arranged radially outside the portion of the interface arranged radially aligned with the inner portion of the wide axis.

[0067] Even more preferably, the portion of the interface arranged radially aligned with the inner portion of the narrow axis is arranged radially outside the portion of the interface arranged radially aligned with the inner portion of the wide axis.

[0068] Therefore, radially raised support layers can be used at or near the first and second main circumferential cuts without increasing the risk of scuffing. Such support layers can optimize tire performance, such as its braking performance on wet surfaces (as explained in application PCT / FR2021 / 050698) or its rolling resistance performance.

[0069] The portion of the interface arranged radially aligned with the narrow axial inner portion is the portion of the interface defined by its axial ends, which are defined by two circumferential planes perpendicular to the tire's rotation axis and passing through the axial ends of the narrow axial inner portion. Similarly, the portion of the interface arranged radially aligned with the wide axial outer portion is the portion of the interface defined by its axial ends, which are defined by two circumferential planes perpendicular to the tire's rotation axis and passing through the axial ends of the wide axial outer portion.

[0070] Ideally, but optionally, the tread includes a mixed lateral cut formed in each of the first axial side portion and the second axial side portion.

[0071] Optionally and advantageously, at least 50%, preferably at least 75%, and more preferably at least 90% of the transverse cuts formed in at least one of the first axial side portion and the second axial side portion (preferably at least partially formed in each of the first axial side portion and the second axial side portion) are mixed transverse cuts.

[0072] By reducing the number of lateral cuts other than the mixed lateral cuts, the risk of tire chipping is reduced, especially when the lateral cuts other than the mixed lateral cuts are grooves. When the lateral cuts other than the mixed lateral cuts are grooves, the tire's rolling resistance is also reduced.

[0073] In a preferred but optional embodiment, the curve length of the narrow axial inner portion is at least 20% and at most 75% of the curve length of each mixed transverse cut portion formed in at least one of the first axial side portion and the second axial side portion.

[0074] The greater the curve length of the inner portion of the narrow shaft, the greater the reduction in rolling resistance. If the curve length of the inner portion of the narrow shaft is too large, the length of the outer portion of the wide shaft will be insufficient to achieve optimal drainage.

[0075] Since the tread is designed to contact the ground via the tread surface when the tire is in motion, the curve length is determined in the relevant portion of the tread, and is therefore limited to the tread surface, and thus to the first axial side portion and the second axial side portion.

[0076] Optionally, to optimize rolling resistance, the width of the narrow axial inner portion at the bottom of the cut ranges from 0.2 mm to 0.5 mm.

[0077] In an advantageous embodiment applicable to passenger vehicle tires, the depth of the narrow axial inner portion ranges from 2.0 mm to 5.5 mm, preferably from 3.0 mm to 5.0 mm.

[0078] Optionally, to optimize drainage, the width of the wide axial outward portion at the bottom of the cut ranges from 1.0 mm to 5.0 mm, preferably from 2.0 mm to 4.5 mm.

[0079] In an advantageous embodiment applicable to passenger vehicle tires, the depth of the wide axial outward portion ranges from 2.0 mm to 5.5 mm, preferably from 3.0 mm to 5.0 mm.

[0080] In an optional implementation that can reduce noise generated by tire tread patterns, each hybrid lateral cut includes:

[0081] - The so-called oblique axial inner portion is formed in at least one of the first axial side portion and the second axial side portion and forms an average angle of greater than or equal to 15°, preferably greater than or equal to 20°, with respect to the axial direction. The oblique axial inner portion is the innermost axial portion of the mixed transverse cut in at least one of the first axial side portion and the second axial side portion.

[0082] - The so-called straight axial outer portion is formed in at least one of the first axial side portion and the second axial side portion, and the average angle formed with the axial direction is strictly less than the average angle of the oblique axial inner portion and is arranged axially outside the oblique axial inner portion. The straight axial outer portion is the outermost axial portion of the mixed transverse cut in at least one of the first axial side portion and the second axial side portion.

[0083] In the portion of the tread surface corresponding to the axially inner part of the mixed lateral cut, the contact patch is straight. Conversely, in the portion of the tread surface corresponding to the axially outer part of the mixed lateral cut, the contact patch is rounded due to the tire's curvature. Because the contact patch angle in the obliquely inner part is relatively large and straight, the leading edge of the obliquely inner part gradually (i.e., over a relatively long time interval) contacts the ground, which limits noise compared to a cut that forms an average angle of essentially zero with respect to the axial direction and where the entire leading edge contacts the ground simultaneously. Similarly, because the contact patch angle in the straightly outer part is smaller and rounded, the leading edge also gradually contacts the ground, which also helps limit noise.

[0084] The average angle of a section is determined by taking a straight line between the two endpoints of the section, which are located at the ends of each section and are equidistant from the front and rear edges of each end of the section.

[0085] In some implementations, the inner portion of the oblique axis and the outer portion of the straight axis are adjacent. Adjacent means that no other portion is inserted between the inner portion of the oblique axis and the outer portion of the straight axis along the axial direction.

[0086] In some optional embodiments, the average angle of the straight outer portion is strictly less than 25°, preferably less than or equal to 20°, and more preferably less than or equal to 15°.

[0087] Optionally, the narrow axial inner portion includes at least a portion of the oblique axial inner portion, and the wide axial outer portion includes at least a portion of the straight axial outer portion.

[0088] In the first configuration of the oblique axial inner portion and the straight axial outer portion, the narrow axial inner portion includes:

[0089] - The entire oblique axis inner portion, and

[0090] - The first part of the straight-axis outward section

[0091] The wide axial outer portion includes:

[0092] - The second part of the straight-axis outward portion.

[0093] In the second configuration of the oblique axial inner portion and the straight axial outer portion, the narrow axial inner portion includes:

[0094] - The first part of the inner portion of the oblique axis

[0095] The wide axial outer portion includes:

[0096] - The second part of the inner portion of the oblique axis.

[0097] - The entire straight axis outward portion.

[0098] In the third configuration of the oblique inner portion and the straight outer portion, the narrow inner portion is composed of the oblique inner portion, and the wide outer portion is composed of the straight outer portion.

[0099] In optional embodiments, it is conceivable that the narrow axial inner portion does not enter one of the adjacent first axially outer main circumferential incision and second axially outer main circumferential incision. In these embodiments, the mixed transverse incision is referred to as a blind incision.

[0100] In other optional, preferred embodiments, the narrow axial inward portion enters one of the adjacent first axially outward main circumferential cutouts and second axially outward main circumferential cutouts. Therefore, compared to tires with blind mixed lateral cutouts, tread pattern mobility is improved, thereby improving tire aspect ratio and consequently improving rolling resistance.

[0101] In a preferred or optional embodiment, each mixed transverse cut includes an axial terminal portion formed axially outside at least one of a first axial side portion and a second axial side portion, and communicating with a wide axially outward portion.

[0102] This promotes water drainage from the tread surface (the surface of the tire tread that comes into contact with the ground).

[0103] In an optional embodiment that advantageously improves tire aerodynamic performance, in the meridional section, the angle between the following two is less than or equal to 20°, preferably less than or equal to 15°, more preferably less than or equal to 10°:

[0104] - The first tangent line at the first point of the line connecting the bottom of the axial end portion of the mixed transverse cut and the outer surface of the tire located axially outside it, and

[0105] - The bottom of the axial end portion of the mixed transverse cut is located at the second point, 2.5 mm axially inside the first point of the connecting line, on the second tangent line.

[0106] The distance between the front and rear edges of the mixed transverse cut where the meridional section connects to the connecting line is equal.

[0107] Energy consumption associated with tire use comes not only from rolling resistance generated by the tires but also from aerodynamic drag. In addition to the aspects of this invention related to tire chipping explained above, the inventors have learned that the arrangement of the axial end portions is also important in reducing aerodynamic drag. The inventors have also found that the greater the difference between the slope of the bottom of the axial end portions of these lateral cuts and the slope of the tire's outer surface arranged axially outside the lateral cuts, the greater the interference of the lateral cuts with airflow over the tire surface, and thus the greater the aerodynamic drag. Due to the significantly different slopes, each lateral cut creates an abrupt indentation for circumferential airflow. Conversely, the more similar the slope of the bottom of the axial end portions of these lateral cuts is to the slope of the tire's outer surface arranged axially outside the lateral cuts, the less interference the lateral cuts cause with airflow over the tire surface, and thus the less aerodynamic drag. Due to the relatively similar gradients, each lateral cut creates an indentation that gradually transitions smoothly from the outer surface, with less interference with circumferential airflow.

[0108] Therefore, the first tangent at the first point on the connecting line represents the slope of the tire's outer surface in the aforementioned meridional plane. The second tangent at the second point at the bottom of the axial terminal portion of the cut represents the slope of the bottom of the axial terminal portion of the transverse cut in the aforementioned meridional plane.

[0109] Given that the second point is 2.5 mm away from the first point axially, it can be ensured that the slope is relatively similar at a relatively large distance from the connecting line (i.e., where the depth of the transverse cut begins to increase significantly, and therefore where the airflow interference has the greatest impact on aerodynamic drag).

[0110] Furthermore, given that the second point is 2.5 mm axially away from the first point, an embodiment in which the bottom of the axial end portion of the transverse cut has the same curvature as the outer surface of the tire can be considered, similar to an embodiment in which the bottom of the axial end portion of the transverse cut has a change in curvature near the connecting line. This embodiment can be particularly considered if the connection between the bottom of the transverse cut and the outer surface is formed by a rounded corner or an arc-shaped cross-section.

[0111] The axial end section is specifically designed to drain water from the tread surface, the surface of the tire that contacts the ground. Therefore, the axial end section is essential for achieving good grip on wet surfaces.

[0112] In an optional and advantageous embodiment that facilitates drainage, the distance between the front and rear edges, measured along the connecting line, is greater than or equal to 0.7 mm, preferably ranging from 0.7 mm to 6.0 mm, and more preferably from 3.0 mm to 5.0 mm.

[0113] In a conventional manner, a tire includes a crown, two sidewalls, and two beads, with each sidewall connecting each bead to the crown. Again, in a conventional manner, the crown includes a tread and a crown reinforcement arranged radially inside the tread. The tire also includes a carcass reinforcement anchored in each bead and extending radially in each sidewall, and extending axially in the crown radially inside the crown reinforcement.

[0114] In a conventional manner, a tread reinforcement comprises at least one tread layer including reinforcing elements. These reinforcing elements are preferably fabric filament elements or metal filament elements.

[0115] In an implementation that achieves the performance of a tire referred to as a radial tire as defined by ETRTO, the carcass reinforcement includes at least one carcass layer, said carcass layer or each carcass layer including a carcass filamentary reinforcement element, each carcass filamentary reinforcement element extending substantially in a principal direction forming an absolute value range of 80° to 90° with respect to the circumferential direction of the tire. Attached Figure Description

[0116] The invention will be better understood by reading the following description, which is given by way of non-limiting embodiments only and with reference to the accompanying drawings, in which:

[0117] - Figure 1 This is a top view of the tread of a tire according to the present invention.

[0118] - Figure 2 for Figure 1 Meridional section view of the tire parallel to the tire's axis of rotation.

[0119] - Figure 3 for Figure 1 A cross-sectional view of a tire, showing the arrangement of filamentous reinforcing elements in and below the tread.

[0120] - Figure 4 for Figure 1 A top view of the mixed lateral cut of the tire.

[0121] - Figure 5 for Figure 4 A side view with mixed transverse cuts.

[0122] - Figures 6 to 9 They are Figure 4 and Figure 5Views of different sections VI-VI', VII-VII', VIII-VIII', and IX-IX' of the mixed transverse cuts.

[0123] - Figure 10 for Figure 1 Another mixed lateral cut of the middle tire with Figure 4 Similar views, and

[0124] - Figure 11 In a meridional section parallel to the tire's axis of rotation, Figure 1 A detailed view of the point where the mixed lateral cut of the tire connects to the outer surface of the tire. Detailed Implementation

[0125] The diagram relating to the tire shows reference frames X, Y, and Z, which correspond to the tire's usual axial direction (Y), radial direction (Z), and circumferential direction (X), respectively.

[0126] In the following description and the foregoing, unless otherwise expressly stated, all measurements are taken on an unloaded and inflated tire or on the meridional section of the tire.

[0127] Figures 1 to 3 A tire according to the invention, indicated by overall reference numeral 10, is shown. The tire 10 has a generally torus shape about an axis of rotation substantially parallel to the axial direction Y. The tire 10 is intended for use in passenger vehicles and has a size of 235 / 55 R19. In the various figures, the tire 10 is depicted as brand new, i.e., it has not yet been driven.

[0128] refer to Figure 2 The tire 10 includes a crown 12, which includes a tread 14 intended to contact the ground during driving and a crown reinforcement 16 extending in the circumferential direction X within the crown 12. The tire 10 also includes a gas-tight layer 18 for inflation, which is intended to define a closed internal cavity with the mounting support of the tire 10 when the tire 10 is mounted on a mounting support (e.g., a rim).

[0129] The crown reinforcement 16 includes a working reinforcement 20 and a ring reinforcement 22. The working reinforcement 20 includes at least one working layer, and in this case, two working layers, including a radially inner working layer 24 arranged radially inside the radially outer working layer 26.

[0130] The hoop reinforcement 22 includes at least one hoop layer, in this case including a hoop layer 28.

[0131] The crown reinforcement 16 is radially covered by the tread 14. In this case, the ring reinforcement 22 (in this case, the ring layer 28) is arranged radially outside the working reinforcement 20, and thus is radially inserted between the working reinforcement 20 and the tread 14.

[0132] The tire 10 includes two sidewalls 30 extending radially inwardly over the crown 12. The tire 10 also has two bead 32 located radially inside the sidewalls 30. Each sidewall 30 connects each bead 32 to the crown 12.

[0133] Tire 10 includes a carcass reinforcement 34 anchored in each bead 32 and, in this case, rolled up around a bead line 33. The carcass reinforcement 34 extends radially in each sidewall 30 and axially in the crown 12, radially inside a crown reinforcement 16. The crown reinforcement 16 is radially disposed between the tread 14 and the carcass reinforcement 34. The carcass reinforcement 34 includes at least one carcass layer 36.

[0134] refer to Figure 3 Each working layer 24, 26, hoop layer 28 and carcass layer 36 contains an elastomeric matrix, with one or more filamentary reinforcing elements of the respective layer embedded in the elastomeric matrix.

[0135] The hoop reinforcement 22 (in this case, the hoop layer 28) includes one or more hoop filamentary reinforcement elements 280, which are helically wound circumferentially in a principal direction D0, the principal direction D0 forming an angle AF with the circumferential direction X of the tire 10 with an absolute value less than or equal to 10°, preferably less than or equal to 7°, and more preferably less than or equal to 5°. In this case, AF = -5°.

[0136] The radial inner working layer 24 and the radial outer working layer 26 each include working filament reinforcing elements 240 and 260 extending along principal directions D1 and D2, respectively. These principal directions D1 and D2 form angles AT1 and AT2 with an absolute value strictly greater than 10°, preferably ranging from 15° to 50°, and more preferably from 15° to 30°, opposite in orientation to the circumferential direction X of the tire 10. In this case, AT1 = -26° and AT2 = +26°.

[0137] The carcass layer 36 includes carcass filamentary reinforcing elements 360 that extend along a principal direction D3, which forms an angle AC with the circumferential direction X of the tire 10 with an absolute value greater than or equal to 60°, preferably in the range of 80° to 90°, and in this case AC = +90°.

[0138] Each hoop-shaped filamentary reinforcing element 280 typically comprises two multifilament strands, each composed of yarns of aliphatic polyamide monofilaments (nylon in this case) with a yarn count of 140 tex. These two multifilament strands are each helically twisted in one direction at 250 turns / meter, and then helically twisted together in the opposite direction at 250 turns / meter. The two multifilament strands are spirally wound around each other. Alternatively, a hoop-shaped filamentary reinforcing element may be used, comprising one multifilament strand composed of yarns of aliphatic polyamide monofilaments (nylon in this case) with a yarn count of 140 tex and another multifilament strand composed of yarns of aramid monofilaments (aramid in this case) with a yarn count of 167 tex. These two multifilament strands are each helically twisted in one direction at 290 turns / meter, and then helically twisted together in the opposite direction at 290 turns / meter. The two multifilament strands are spirally wound around each other. This variant form makes AT1 = -29° and AT2 = +29°.

[0139] Each working filamentary reinforcing element 240, 260 is an assembly having two steel monofilaments spirally wound at a pitch of 14 mm, each monofilament having a diameter of 0.30 mm. Alternatively, an assembly of six steel monofilaments with a diameter of 0.23 mm can be used, comprising an inner layer of two monofilaments spirally wound together at a pitch of 12.5 mm in a first direction (e.g., the Z direction), and an outer layer of four monofilaments spirally wound together around the inner layer at a pitch of 12.5 mm in a second direction opposite to the first direction (e.g., the S direction). In another variant, each working filamentary reinforcing element consists of a single steel monofilament with a diameter of 0.30 mm. More typically, the diameter of the steel monofilament ranges from 0.25 mm to 0.32 mm.

[0140] Each carcass filamentary reinforcing element 360 typically comprises two multifilament strands, each composed of polyester monofilament yarn (PET in this case). These two multifilament strands are each helically twisted in one direction at 240 turns / meter, and then helically twisted together in the opposite direction at 240 turns / meter. Each of these multifilament strands has a yarn count of 220 tex. In other variant forms, a yarn count of 144 tex and a twist of 420 turns / meter, or a yarn count of 334 tex and a twist of 270 turns / meter, may be used.

[0141] refer to Figure 1 and Figure 2The tread 14 includes a tread surface 38 through which the tread 14 contacts the ground. The tread surface 38 is designed to contact the ground when the tire 10 is traveling on the ground. The tread surface is axially defined by a first axial edge 41 and a second axial edge 42 passing through each point N arranged on both sides of the midplane M, wherein for each point N, the angle between the tangent T on the tread surface 38 and the straight line R parallel to the axial direction Y and passing through said point is equal to 30°.

[0142] The tread 14 includes an axial central portion P0 and a first axial side portion P1 and a second axial side portion P2. The first axial side portion P1 and the second axial side portion P2 are arranged axially outside the axial central portion P0 and are on both sides of the axial central portion P0 relative to the midplane M of the tire 10.

[0143] Without being specific to the illustrated embodiment, the axial width L0 of the axial central portion P0 is greater than or equal to 50% of the axial width L of the tread surface 38 of the new tire 10, preferably greater than or equal to 60% of the axial width L of the tread surface 38 of the new tire 10, and less than or equal to 80% of the axial width L of the tread surface 38 of the new tire 10, preferably less than or equal to 70% of the axial width L of the tread surface 38 of the new tire 10. The axial widths L1 and L2 of the first axial side portion P1 and the second axial side portion P2 are each less than or equal to 25% of the axial width L of the tread surface 38 of the new tire 10, preferably less than or equal to 20% of the axial width L of the tread surface 38 of the new tire 10, and greater than or equal to 5% of the axial width L of the tread surface 38 of the new tire 10, preferably greater than or equal to 10% of the axial width L of the tread surface 38 of the new tire 10. The ratio of the axial width L0 of the central portion P0 to the axial widths L1 and L2 of the first axial side portion P1 and the second axial side portion P2 is greater than or equal to 3.0, preferably in the range of 3.0 to 5.0, and more preferably in the range of 4.0 to 4.5.

[0144] The tread 14 includes N>1 main circumferential cuts, which in this case are N main circumferential grooves. The main circumferential cuts include a first main circumferential cut, a second main circumferential cut, a third main circumferential cut, and a fourth main circumferential cut, respectively indicated by reference numerals 52, 54, 56, and 58. The first main circumferential cut 52 and the second main circumferential cut 54 are arranged axially on both sides of the midplane M of the tire 10, and are the outermost main circumferential cuts of the tread 14 in the axial direction.

[0145] The first axial side portion P1 and the second axial side portion P2 are respectively arranged axially outside the first axially outer main circumferential cut 52 and the second axially outer main circumferential cut 54. 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 P2 extends axially from the second axial edge 42 of the tread surface 38 to the second main circumferential cut 54.

[0146] Each primary circumferential cut 52 to 58 is provided with a rounded chamfer. The depths Ha1 and Ha2 of each primary circumferential cut 52 to 58 range from 4.0 mm to the tread height Hs, preferably from 5.0 mm to the tread height Hs, and more preferably from 5.5 mm to the tread height Hs. Depths Ha1 and Ha2 are each greater than or equal to 50% of the tread height Hs. In this case, Hs = 6.5 mm, Ha1 = 6.0 mm for the first axially outward primary circumferential cut 52 and the second axially outward primary circumferential cut 54, and Ha2 = 6.5 mm for each primary circumferential cut 56 and 58 of the axially central portion P0. Therefore, the depths of each primary circumferential cut 52, 54, 56, and 58 advantageously satisfy Ha1 / Hs ≥ 75%, Ha2 / Hs ≥ 75%, more preferably Ha1 / Hs ≥ 90%, and Ha2 / Hs ≥ 90%.

[0147] The axial widths La1, La2, La3, and La4 of each main circumferential cut 52 to 58 are each greater than or equal to 1.0 mm, preferably greater than or equal to 5.0 mm, and more preferably ranging from 5.0 mm to 20.0 mm. In this case, La1 = 15.0 mm, La2 = 13.0 mm, La3 = 10.30 mm, and La4 = 7.0 mm.

[0148] The axial central portion P0 includes central ribs, which in this case are the first central rib, the second central rib, and the third central rib, respectively, indicated by reference numerals 62, 64, and 66. Each central rib 62, 64, and 66 is arranged axially between two adjacent main circumferential cuts 52 to 58 and is defined axially by the two adjacent main circumferential cuts 52 to 58.

[0149] Each central rib 62, 64, 66 includes transverse cuts 74, 75, 76, the width of which is less than or equal to 1.0 mm, more preferably strictly less than or equal to 0.6 mm, and in this case equal to 0.4 mm. The depth Hb of each transverse cut 74, 75, 76 is equal to 3.5 mm.

[0150] The first axial side portion P1 and the second axial side portion P2 each include a first side rib and a second side rib, respectively indicated by reference numerals 68 and 70, in which case they are respectively composed of each first side rib 68 and the second side rib 70.

[0151] The tread 14 includes lateral cuts 77 and 78, which are formed at least partially in at least one of the first axial side portion P1 and the second axial side portion P2, in which case they are formed at least partially in each of the first axial side portion P1 and the second axial side portion P2. For the reasons described above, these lateral cuts 77 and 78 are referred to as mixed cuts. At least 50%, preferably at least 75%, more preferably at least 90% of the lateral cuts are formed at least partially in at least one of the first axial side portion P1 and the second axial side portion P2 (in which case they are formed at least partially in each of the first axial side portion P1 and the second axial side portion P2), in which case 100% of the lateral cuts are mixed lateral cuts 77 and 78.

[0152] refer to Figures 4 to 9 The mixed lateral cuts 78 will now be described; when the tire is mounted on the wheel, these mixed lateral cuts are located on the outside of the wheel, and therefore also on the outside of the vehicle.

[0153] Each mixed transverse cut 78 is provided with a chamfer 79 and is defined circumferentially by a front edge 85 and a rear edge 87. Each mixed transverse cut 78 includes a so-called narrow axial inner portion 80, a so-called wide axial outer portion 82, and an axial terminal portion 83, which is formed axially outside the second axial side portion P2 and communicates with the wide axial outer portion 82. Each mixed transverse cut 78 has a curve length Lot for each mixed transverse cut portion formed in the second axial side portion P2. In this case, Lot = 45 mm. Portions 80, 82, and 83 are adjacent.

[0154] The narrow axial inner portion 80 is the innermost axial portion of the mixed transverse cut 78 in the second axial side portion P2. The narrow axial inner portion 80 extends from the inner axial end 84 to the outer axial end 86. The narrow axial inner portion 80 enters the adjacent main circumferential cut 54. The curve length Loi of the narrow axial inner portion is at least 20% and at most 75% of the curve length Lot. In this case, Loi = 23 mm, which is 51% of the curve length Lot.

[0155] The wide axial outer portion 82 communicates with the narrow axial inner portion 80 and is arranged axially outside the narrow axial inner portion 80. The wide axial outer portion 82 is the outermost axial portion of the mixed transverse cut 78 in the second axial side portion P2. The wide axial outer portion 82 extends from the axial inner end 88 (which in this case coincides with the axial outer end 86) to the axial outer end 90. The wide axial outer portion has a curve length Loe. In this case, Loe = 22 mm.

[0156] The axial end portion 83 extends from the inner axial end 91 (which in this case coincides with the outer axial end 90) to the outer axial end. The outer axial end 93 is represented by the connecting line 92 between the bottom 94 of the axial end portion 83 of the mixed transverse cut 78 and the outer surface 96 of the tire 10 located axially outside it.

[0157] It is important to note that, in Figure 4 For clarity, the curve lengths are not shown as lengths measured along a curve equidistant from the front edge 85 and the rear edge 87 between the two ends of the mixing transverse cut 78 or each portion 80, 82. However, as stated above, they must be measured along a curve equidistant from the front edge 85 and the rear edge 87 between the two ends of the mixing transverse cut 78 or each portion 80, 82.

[0158] like Figures 6 to 9 As shown, the narrow axial inner portion 80 has a bottom 94 with a mixed transverse cut, at which the width Lai ranges from 0.2 mm to 0.6 mm, preferably from 0.2 mm to 0.5 mm, in which case the width Lai = 0.4 mm. The depth of the narrow axial inner portion 80 ranges from 2.0 mm to 5.5 mm, preferably from 3.0 mm to 5.0 mm, in which case it equals 4.4 mm.

[0159] The width Lae of the wide axial outward portion at the bottom 94 of the cut ranges 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 mentioned above, the width Lae is the maximum distance between the two main sides 97 and 98 of the wide axial outward portion 82 at the bottom 94 of the cut, and therefore in this case, it is measured at the end 90. Figure 1 As shown, the wide axial outward portion 82 has randomly distributed different widths Lae to limit howling noise. In this case, the different widths Lae used are equal to 3.1 mm, 3.7 mm, and 4.1 mm. The depth of the wide axial outward portion 82 ranges from 2.0 mm to 5.5 mm, preferably from 3.0 mm to 5.0 mm, and in this case equals 4.6 mm.

[0160] like Figure 4 , Figure 5 , Figure 8 and Figure 9 As shown, the wide-axis outward portion has two main side surfaces, namely the leading edge surface 97 and the trailing edge surface 98, which are connected to the bottom 94 of the mixed transverse cut 78 by a fillet 99.

[0161] Within the axial end portion 83, the distance dr between the front edge 85 and the rear edge 87, measured along the connecting line 92, is greater than or equal to 0.7 mm, preferably ranging from 0.7 mm to 6.0 mm, and more preferably from 3.0 mm to 5.0 mm. In this case, different dr values ​​are equal to 3.4 mm, 3.6 mm, and 4.7 mm.

[0162] Back Figure 4 and Figure 5 Each mixed transverse cut 78 includes a so-called oblique axial inner portion 100 and a so-called straight axial outer portion 102, the oblique axial inner portion 100 being formed in a second axial side portion P2, and the straight axial outer portion 102 being arranged axially outside the oblique axial inner portion 100 and also formed in the second axial side portion P2. Portions 100 and 102 are adjacent to each other.

[0163] The oblique axial inner portion 100 forms an average angle A with the axial direction Y greater than or equal to 15°, preferably greater than or equal to 20°, in which case A = 23°. The oblique axial inner portion 100 is the innermost axial portion of the mixed transverse cut 78 in the second axial side portion P2.

[0164] The average angle B formed by the straight outer portion 102 and the axial direction Y is strictly less than the average angle of the oblique inner portion 100. The average angle of the straight outer portion 102 is strictly less than 25°, preferably less than or equal to 20°, more preferably less than or equal to 15°, and in this case equal to 8°. The straight outer portion 102 is the outermost axial portion of the mixed transverse cut 78 in the second axial side portion P2.

[0165] In this configuration, the narrow axial inner portion 80 includes at least a portion of the oblique axial inner portion 100 (in this case, the entire oblique axial inner portion 100) and a first portion of the straight axial outer portion 102 extending to the common ends 86, 88 of portions 80, 82. The wide axial outer portion 82 includes a second portion of the straight axial outer portion extending from the ends 86, 88 to the second axial edge 42 of the tread surface 38.

[0166] Figure 10 A mixed transverse cut 77 is shown. For simplicity, the explanation of mixed transverse cut 78 is omitted. Figure 4 The components shown are similar to those in the diagram. Figure 10 The same reference numerals were used.

[0167] Unlike the mixed transverse cut 78, each mixed transverse cut 77 satisfies Lot = 38 mm, Loi = 14 mm, and Loe = 24 mm. Furthermore, angles A and B satisfy A = 25° and B = 8°.

[0168] Back Figure 2 The tire 10 includes a tread layer 110 and a support layer 112 of the tread layer 110. The support layer 112 is arranged radially inside the tread layer 110. The tread layer 110 and the support layer 112 are connected by an interface 114. The support layer 112 has extremely low rolling resistance, characterized by a dynamic loss tanDMAX23 of 0.095 measured at room temperature of 23°C and a frequency of 10 Hz according to ASTM D-5992-96.

[0169] Still Figure 2 In the meridional section, the defined wear trajectory 116 is parallel to the tread surface 38 of the tire 10 and passes through the radially outer surface 118 of the defined wear indicator 120. In the illustrated embodiment, at least a portion 122 of the interface 114 is radially aligned with at least a portion 124 of the interface 114 and the wide axial inner portion 82.

[0170] The bottom 94 of the mixed lateral cut 77 is also shown. The entire bottom 94 of each mixed lateral cut 77, 78 is arranged radially outside the interface 114 between the tread layer 110 and the support layer 112. Furthermore, the radial distance di between at least a portion 126 of the bottom 94 of the narrow axially inner portion 80 and the interface 114 is strictly greater than the radial distance de between at least a portion 128 of the bottom 94 of the wide axially outer portion 82 and the interface 114.

[0171] In the illustrated embodiment, at least 60%, preferably at least 75% (100% in this case) of the curve length Loi of the narrow axial inner portion 80 is radially distancing di from the interface 114, which is strictly greater than the average radial distance dem between the bottom 94 of the wide axial outer portion 82 and the interface 114.

[0172] More specifically, the average radial distance dim between the bottom 94 of the narrow axial inner portion 80 and the interface 114 is strictly greater than the average radial distance dem between the bottom 94 of the wide axial outer portion 82 and the interface 114. The average radial distance dem between the bottom of the wide axial outer portion 82 and the interface 114 ranges from 0.3 mm to 1.0 mm, preferably from 0.4 mm to 0.9 mm. The average radial distance dim between the bottom 94 of the narrow axial inner portion 80 and the interface 114 ranges from 0.5 mm to 1.5 mm, preferably from 0.6 mm to 1.2 mm. In this case, dem = 0.5 mm and dim = 1.0 mm.

[0173] Figure 11 It shows Figure 10 The diagram shows the meridional section XII-XII', which is located at a distance equal to the front edge 85 and the rear edge 87 connected by the connecting line 92. The bottom 94 of the axial terminal portion 83 includes a fillet 130, forming the junction between the bottom 94 and the connecting line 92. Figure 11 The first tangent T3 of point P3 and the second tangent T4 of point P4 are shown. Point P3 is a point in plane XII-XII', and is a point on connecting line 92. Point P4 is a point at the bottom 94 of the axial terminal portion 83 of the mixed transverse cut 77, located 2.5 mm axially inside point P3 on connecting line 92. Figure 11 In this diagram, the 2.5 mm distance is represented by a dashed circle with a diameter of 5.0 mm, centered at the first point P3. The angle K between the first tangent T3 and the second tangent T4 is less than or equal to 20°, preferably less than or equal to 15°, and in this case equal to 11°. In other, even more advantageous, embodiments, the angle K may be less than or equal to 10°.

[0174] The present invention is not limited to the above-described embodiments.

Claims

1. A tire (10) for a passenger vehicle, the tire (10) comprising a tread (14) designed to contact the ground via a tread surface (38) when the tire (10) is in motion, the tread (14) comprising: - Main circumferential cuts (52, 54, 56, 58), the depths (Ha1, Ha2) of which are greater than or equal to 50% of the tread height (Hs), and include a first axially outer main circumferential cut and a second axially outer main circumferential cut (52, 54) arranged axially on both sides of the midplane (M) of the tire (10), the first axially outer main circumferential cut and the second axially outer main circumferential cut (52, 54) being the outermost axial main circumferential cuts of the tread (14). - A first axial side portion (P1) is arranged axially outside the first axial outer main circumferential cut (52) and extends axially from the first axial edge (41) of the tread surface (38) to the first axial outer main circumferential cut (52). - The second axial side portion (P2) is arranged axially outside the second axial outer main circumferential cut (54) and extends axially from the second axial edge (42) of the tread surface (38) to the second axial outer main circumferential cut (54). The tire (10) includes a tread layer (110) and a support layer (112) of the tread layer (110), the support layer (112) being arranged radially inside the tread layer (110). Characterized by the fact that the tread (14) includes so-called mixed lateral cuts (77, 78), which are formed at least partially in at least one of a first axial side portion and a second axial side portion (P1, P2), each mixed lateral cut (77, 78) comprising: -The so-called narrow axial inner portion (80), the width (Lai) of which at the bottom (94) of the cut ranges from 0.2 mm to 0.6 mm, the narrow axial inner portion (80) is the innermost axial portion of the mixed transverse cut (77, 78) of at least one of the first axial side portion and the second axial side portion (P1, P2), -The so-called wide axial outer portion (82), the width (Lae) of which ranges from 0.7 mm to 5.0 mm at the bottom (94) of the cut, communicates with the narrow axial inner portion (80) and is arranged axially outside the narrow axial inner portion (80), the wide axial outer portion (82) being the outermost axial portion of the mixed transverse cut (77, 78) of at least one of the first axial side portion and the second axial side portion (P1, P2), Each mixed lateral cut (77, 78) has a mixed lateral cut bottom (94), the entire bottom (94) of each mixed lateral cut (77, 78) being arranged radially on the outside of the interface (114) between the tread layer (110) and the support layer (112). The radial distance (di) between at least a portion (126) of the bottom (94) of the narrow axial inner portion (80) and the interface (114) is strictly greater than the radial distance (de) between at least a portion (128) of the bottom (94) of the wide axial outer portion (82) and the interface (114).

2. The tire (10) according to claim 1, wherein, At least 60% of the curve length (Loi) of the inner portion of the narrow axis (80) is radially distanced (di) from the interface (114) from the interface (114) to the interface (114) from the interface (114) from the interface (94) of the outer portion of the wide axis (82).

3. The tire (10) according to claim 1, wherein, The average radial distance (dim) between the bottom (94) of the narrow axial inner portion (80) and the interface (114) is strictly greater than the average radial distance (dem) between the bottom (94) of the wide axial outer portion (82) and the interface (114).

4. The tire (10) according to claim 1, wherein, At least a portion (122) of the interface (114) and the narrow axial inner portion (80) are arranged radially on the outside of the interface (114) and the wide axial inner portion (82) which are arranged radially on the outside of the interface (114) and the wide axial inner portion (82).

5. The tire (10) according to claim 1, wherein, The tread (14) includes mixed transverse cuts (77, 78) formed in part in each of the first axial side portion and the second axial side portion (P1, P2).

6. The tire (10) according to claim 1, wherein, At least 50% of the transverse cuts formed in at least one of the first axial side portion and the second axial side portion (P1, P2) are mixed transverse cuts (77, 78).

7. The tire (10) according to claim 1, wherein, The curve length (Loi) of the narrow axial inner portion (80) is at least 20% and at most 75% of the curve length (Lot) of the portion of each mixed transverse cut (77, 78) formed in at least one of the first axial side portion and the second axial side portion (P1, P2).

8. The tire (10) according to claim 1, wherein, The width (Lai) of the narrow axial inner portion (80) at the bottom of the cut (94) ranges from 0.2 mm to 0.5 mm.

9. The tire (10) according to claim 1, wherein, The width (Lae) of the wide axial outward portion (82) at the bottom of the cut (94) ranges from 1.0 mm to 5.0 mm.

10. The tire (10) according to claim 1, wherein, Each mixed transverse cut (77, 78) includes: -The so-called oblique axial inner portion (100), which is formed in at least one of the first axial side portion and the second axial side portion (P1, P2) and forms an average angle (A) greater than or equal to 15° with the axial direction (Y), the oblique axial inner portion (100) is the innermost axial portion of the mixed transverse cut (77, 78) in at least one of the first axial side portion and the second axial side portion (P1, P2), -The so-called straight axial outer portion (102), which is formed in at least one of the first axial side portion and the second axial side portion (P1, P2) and forms an average angle (B) with the axial direction (Y) that is strictly smaller than the average angle (A) of the oblique axial inner portion (100), and is arranged axially outside the oblique axial inner portion (100), the straight axial outer portion (102) being the outermost axial portion of the mixed transverse cut (77, 78) in at least one of the first axial side portion and the second axial side portion (P1, P2).

11. The tire (10) according to claim 10, wherein, The average angle (B) of the outer portion of the straight axis is strictly less than 25°.

12. The tire (10) according to claim 10 or 11, wherein: - The narrow axial inner portion (80) includes at least a portion of the oblique axial inner portion (100), and - The wide axial outward portion (82) includes at least a portion of the straight axial outward portion (102).

13. The tire (10) according to claim 1, wherein, The narrow axial inner portion (80) enters one of the first axial outer main circumferential incision and the second axial outer main circumferential incision (52, 54) adjacent to it.

14. The tire (10) according to claim 1, wherein, Each mixed transverse cut (77, 78) includes an axial terminal portion (83) formed axially outside at least one of a first axial side portion and a second axial side portion (P1, P2) and communicating with a wide axially outward portion (82).

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