Tyre comprising equivalent cut-outs of different lengths

Abstract

The invention relates to a tyre that comprises first and second cut-outs (402, 404) comprising portions joined by inflection zones (4024, 4044). The first cut-out (402) has a length (L1) different from the length (L2) (X) of the second cut-out (404). An angle formed by the direction of the first portion (4021) and the direction of the second portion (4022) of the first cut-out (402) is substantially equal to an angle formed by the direction of the first portion (4041) and the direction of the second portion (4042) of the second cut-out (404). An angle formed by the direction of the second portion (4022) and the direction of the third portion (4023) of the first cut-out (402) is substantially equal to an angle formed by the direction of the second portion (4042) and the direction of the third portion (4043) of the second cut-out (404).

Description

Pneumatics comprising similar cutouts of different lengths

[0001] The present invention relates to a tire. A tire is defined as a band designed to form a cavity by cooperating with a support element, for example a rim, this cavity being capable of being pressurized to a pressure greater than atmospheric pressure. A tire according to the invention has a substantially toroidal structure of revolution around a principal axis of the tire.

[0002] FR3012767 is known to be a passenger vehicle tire comprising a tread with circumferential ribs and cutouts in each of the circumferential ribs.

[0003] For the purpose of limiting siren noise, the cutouts include first, second and third cutouts such that each first, second and third cutout has a circumferential length different from the circumferential length of each other first, second and third cutout.

[0004] In order to reduce the noise generated by this tire, each first, second and third cut opens into each of the first and second circumferential cuts delimiting said circumferential rib into respectively first and second opening zones such that the azimuth of a point in the first opening zone of one of the first, second and third cuts is substantially circumferentially aligned with the azimuth of a point in the second opening zone of another of the first, second and third cuts.

[0005] Each first, second, and third segment comprises first, second, and third portions. The first and second portions are directly joined to each other by a first inflection zone, and the third portion is directly joined to the second portion by a second inflection zone. The second portion is arranged axially between the first and third portions.

[0006] To mold each first, second, and third cutout, molding elements are used, for example, called slats when the cutout widths are relatively small. These molding elements have a shape complementary to the cutouts they are designed to mold in the tire and are most often manufactured by stamping a metal plate. To achieve the desired angle between the different sections, it is therefore necessary to use as many stamping dies as there are different angles. The number of dies required is thus relatively large, which makes the molding elements expensive and time-consuming to manufacture.

[0007] In addition to the relatively large number of tools, the complexity of their design is made high due to the azimuth arrangement constraint described earlier, which requires adjusting the length according to the circumferential direction of each cut.

[0008] The invention aims at a tire that generates reduced noise and is molded using simpler molding elements.

[0009] To this end, the invention relates to a tire comprising a tread including at least one circumferential rib delimited by first and second circumferential cutouts and cutouts formed in said circumferential rib and opening into each of the first and second circumferential cutouts, the cutouts including first and second cutouts, each first and second cutout including first, second and third portions, the first portion and second portion of each first and second cutout being directly joined to each other by a first inflection zone, the second portion and third portion of each first and second cutout being directly joined to each other by a second inflection zone,the second portion of each first and second cut being arranged axially between the first and third portions respectively of each first and second cut, the average direction of the first portion of each first and second cut being not parallel to the average direction of the second portion respectively of each first and second cut, the average direction of the third portion of each first and second cut is not parallel to the average direction of the second portion respectively of each first and second cut, the first cut has a length along the circumferential direction different from the length along the circumferential direction of the second cut, each first and second cut opens into each of the first and second circumferential cuts delimiting said circumferential rib in respectively first and second opening zones,The azimuth of a point in the first outlet zone of the first cutout is substantially circumferentially aligned with the azimuth of a point in the second outlet zone of the second cutout; an angle formed by the average direction of the first portion and the average direction of the second portion of the first cutout is substantially equal to an angle formed by the average direction of the first portion and the average direction of the second. portion of the second cut, an angle formed by the average direction of the second portion and the average direction of the third portion of the first cut is substantially equal to an angle formed by the average direction of the second portion and the average direction of the third portion of the second cut, the first portion of the first cut extends along an average direction substantially parallel to the average direction along which the first portion of the second cut extends, the second portion of the first cut extends along an average direction substantially parallel to the average direction along which the second portion of the second cut extends, the third portion of the first cut extends along an average direction substantially parallel to the average direction along which the third portion of the second cut extends,and the length of the first portion of the first cut is different from the length of the first portion of the second cut and / or the length of the second portion of the first cut is different from the length of the second portion of the second cut and / or the length of the third portion of the first cut is different from the length of the third portion of the second cut.

[0010] The invention simplifies the manufacturing of the molding elements for the cutouts and reduces the noise generated by the pneumatic system. Indeed, because the angles between the first and second portions, and between the second and third portions of each first and second cutout, are equal, a single stamping tool is sufficient to manufacture two different molding elements, i.e., two with different circumferential lengths, allowing for the molding of the first and second cutouts. The circumferential length can be easily adjusted by lengthening or shortening either portion without altering the angle formed by the mean directions of these first and second portions. Thus, the azimuth arrangement constraint is met. Furthermore, the first, second, and third portions of each cutout are substantially parallel to each other.We then limit the variations in angles formed between each portion of two different cuts and the axial direction, which makes it possible to further reduce the noise generated by the tire in accordance with the invention.

[0011] Unlike cuts made up of two portions in which the inflection zones are necessarily axially offset from each other with respect to the In other cases, it is possible, although not necessary, to center the cut relative to the second portion and thus position each first and second inflection zone axially symmetrically relative to the middle of each cut, which simplifies the tooling for manufacturing the molding elements.

[0012] By "directly joined to one another by an inflection zone," we mean that no other portion of said cut is axially interposed between the two portions concerned. The inflection zone represents the change in curvature of the cut between the portions concerned. We also mean that said cut is not interrupted between the portions concerned.

[0013] The inflection zone includes an inflection point located on the neutral fiber of each cut and corresponding to the point at which the neutral fiber changes direction of curvature when passing from the first portion to the second portion and vice versa.

[0014] Each first, second and third portion can be straight or curved.

[0015] In the case of a straight section, determining the average direction is obvious.

[0016] In the case of a curved portion, the average direction of said portion is the direction along which a straight line extends from the two endpoints of said portion located on the neutral axis. Since the first and second portions are directly joined by the inflection zone described above, the average direction of the first portion extends along the direction of a straight line passing through one endpoint of the first portion and the inflection point coinciding with the other endpoint of the first portion. The average direction of the second portion extends along the direction of a straight line passing through one endpoint of the second portion and the inflection point coinciding with the other endpoint of the second portion. The average direction of the third portion extends along the direction of a straight line passing through one endpoint of the third portion and the inflection point coinciding with the other endpoint of the third portion.

[0017] The circumferential length of said cut is equal to the circumferential distance between the two furthest points of said cut in the circumferential direction.

[0018] Due to the lack of collinearity between the average direction of the first segment and the average direction of the second segment, the junction between the first and second segments forms an inflection point. Similarly, due to the lack of collinearity between the average direction of the third and second segments, the junction between the third and second segments also forms an inflection point. Each junction can be angular or rounded.

[0019] Two average directions are substantially parallel if the angle formed by the two average directions is less than or equal to 5°, preferably less than or equal to 2°.

[0020] Similarly, an angle is substantially equal to another angle if the difference between the two angles is less than or equal to 5°, preferably less than or equal to 2°.

[0021] Conversely, an average direction is not parallel to another average direction if the angle formed by the two average directions is strictly greater than 5°, preferably strictly greater than 2°.

[0022] The angle formed by two average directions is considered to be the smallest angle between these two average directions.

[0023] The length of a segment is the length measured along the average direction in which that segment extends. Thus, in the case of a straight segment, the length is the distance measured between the two endpoints of that segment. In the case of a curved segment, the length is the distance measured along the line joining the two endpoints of that segment.

[0024] By substantially aligned, we mean that the azimuths are circumferentially distant from each other by no more than 5% of the average distance separating the two cuts made in said circumferential rib.

[0025] A cutout on the running surface has two main characteristic dimensions: a width and a curvilinear length such that the curvilinear length is at least twice the width. A cutout is therefore delimited by at least two main lateral faces that determine its curvilinear length and are connected by a base. The two main lateral faces are separated by a non-zero distance, called the width of the cutout.

[0026] The width of a cut on a new tire is the maximum distance between the two main sidewalls. By default, if the cut does not include a chamfer, it is measured at a radial dimension coinciding with the tread surface. By default, if the cut includes a chamfer, it is measured at the outermost radial dimension of the cut and the innermost radial dimension of the chamfer. The width is measured substantially perpendicular to the main sidewalls. If a width other than the default width is specified, for example, a width at a particular dimension, the width is equal to the smallest distance between the two main sidewalls at that particular dimension of the cut.

[0027] The depth of a cut on a new tire is the maximum radial distance between the bottom of the cut and its projection onto the ground during tire rolling. The maximum depth of the cuts is called the tread depth. of sculpture.

[0028] A cut can be transverse or circumferential.

[0029] A transverse cut is such that the cut extends along a mean direction forming an angle strictly greater than 30°, preferably greater than or equal to 45°, with the circumferential direction of the tire, i.e., forming an angle less than or equal to 60°, preferably strictly less than 45°, with the axial direction of the tire. The mean direction is the shortest curve joining the two ends of the cut and parallel to the tread surface. A transverse cut may be continuous, i.e., not interrupted by a tread block or another cut, so that the two principal lateral faces determining its length are uninterrupted along the length of the transverse cut.A transverse cut can also be discontinuous, that is, interrupted by one or more blocks of sculpture and / or one or more cuts so that the two main lateral faces determining its length are interrupted by one or more blocks of sculpture and / or one or more cuts.

[0030] A circumferential cut is such that the cut extends along a mean direction forming an angle of 30° or less, preferably 10° or less, with the circumferential direction of the tire, i.e., forming an angle strictly greater than 60°, preferably strictly greater than 80°, with the axial direction of the tire. The mean direction is the shortest curve joining the two ends of the cut and parallel to the tread surface. In the case of a continuous circumferential cut, the two ends coincide and are joined by a curve making a complete rotation of the tire. A circumferential cut can be continuous, i.e., not interrupted by a tread block or another cut, so that the two principal lateral faces determining its length are uninterrupted over the entire circumference of the tire.A circumferential cut can also be discontinuous, that is to say interrupted by one or more blocks of tread and / or one or more cuts so that the two main lateral faces determining its length are interrupted by one or more blocks of tread and / or one or more cuts over the whole of one turn of the tire.

[0031] In the case of a cross-section, the lateral faces are called the leading face and the trailing face, and each is provided respectively with a leading edge and a trailing edge, the leading edge being the edge which, for a given circumferential line, enters the contact area before the trailing edge.

[0032] In embodiments allowing for optional improvement of braking On dry ground, each transverse cut is fitted with chamfers. A chamfer of a transverse cut can be a straight chamfer or a rounded chamfer. A straight chamfer is formed by a flat face inclined relative to the leading or trailing face it extends to the leading or trailing edge circumferentially delimiting the transverse cut. A rounded chamfer is formed by a curved face connecting tangentially to the leading or trailing face it extends. A chamfer of a transverse cut is characterized by a height and a width equal respectively to the radial distance and the distance along a direction perpendicular to the leading or trailing faces between the point where the leading or trailing face extended by the chamfer is common to the leading or trailing edge circumferentially delimiting the transverse cut.

[0033] In certain embodiments that optionally improve braking on dry surfaces and also lateral grip on dry surfaces, at least one of the circumferential cutouts is provided with chamfers. A chamfer of a circumferential cutout can be a straight chamfer or a rounded chamfer. A straight chamfer is formed by a flat face inclined relative to the axially inner and outer faces that it extends to the axially inner or outer edge that axially delimits the circumferential cutout. A rounded chamfer is formed by a curved face that connects tangentially to the axially inner or outer face that it extends.A chamfer of a circumferential cut is characterized by a height and a width equal respectively to the radial distance and the axial distance between the common point between the axially internal or external face extended by the chamfer and the axially internal or external edge axially delimiting the circumferential cut.

[0034] A circumferential rib is a rib delimited axially by first and second axially adjacent circumferential cuts.

[0035] The tire according to the invention has a substantially toroidal shape around an axis of revolution substantially coinciding with the axis of rotation of the tire. This axis of revolution defines three directions conventionally used by those skilled in the art: an axial direction, a circumferential direction, and a radial direction.

[0036] Axial direction refers to the direction substantially parallel to the axis of revolution of the tire, that is, the axis of rotation of the tire.

[0037] By circumferential direction, we mean the direction which, in each meridian plane, is substantially perpendicular to both the axial direction and to a radius of the tire (in other words, tangent to a circle whose center is on the axis of rotation of the tire).

[0038] Radial steering refers to steering along a radius of the tire, that is- that is to say any direction intersecting the axis of rotation of the tire and substantially perpendicular to this axis.

[0039] By median plane of the tire (denoted M), we mean the plane perpendicular to the axis of rotation of the tire which is located at mid-axial distance of the two ribs and passes through the axial midpoint of the crown reinforcement.

[0040] The circumferential equatorial plane of the tire (denoted E) is defined, in a meridional cross-sectional plane, as the plane passing through the tire's equator, perpendicular to the median plane and the radial direction. The tire's equator, in a meridional cross-sectional plane (a plane perpendicular to the circumferential direction and parallel to the radial and axial directions), is the axis parallel to the tire's axis of rotation and located equidistant between the outermost radial point of the tread intended to be in contact with the ground and the innermost radial point of the tire intended to be in contact with a support, for example, a rim, the distance between these two points being equal to H.

[0041] By meridian plane, we mean a plane parallel to and containing the axis of rotation of the tire and perpendicular to the circumferential direction.

[0042] Radially inside and radially outside refer to the area closest to and further from the tire's axis of rotation, respectively. Axially inside and axially outside refer to the area closer to and further from the tire's median plane, respectively.

[0043] The bead is the portion of the tire designed to allow the tire to be attached to a mounting surface, such as a wheel with a rim. Each bead is specifically designed to make contact with a hook on the rim, enabling it to be secured.

[0044] Any range of values ​​designated by the expression "between a and b" represents the range of values ​​from more than a to less than b (i.e., bounds a and b excluded) while any range of values ​​designated by the expression "from a to b" means the range of values ​​from a to b (i.e., including the strict bounds a and b).

[0045] In some embodiments, the first, second, and any subsequent cutouts are formed in the same circumferential rib. In other embodiments, the first, second, and any subsequent cutouts are formed in at least two separate circumferential ribs.

[0046] In preferred embodiments of the invention, the tires are intended for passenger vehicles as defined in the European Tyre and Rim Technical Organisation (ETRTO) standard, 2021. Such a tire features A cross-section in a meridional plane characterized by a section height H and a nominal section width or bead size S as defined by the European Tyre and Rim Technical Organisation (ETRTO) standard, 2021, such that the H / S ratio, expressed as a percentage, is at most 90 and at least 20, and the nominal section width S is at least 115 mm, preferably at least 175 mm, and at most 385 mm, preferably at most 315 mm. Furthermore, the hook diameter D, defining the diameter of the tire mounting rim, is at least 15 inches and at most 24 inches.

[0047] In preferred embodiments of the invention, the tires are summer tires. Summer tires are defined as tires that are neither all-season tires nor winter tires.

[0048] Winter tires are identified by the M+S marking (M+S stands for "Mud + Snow") and / or the 3PMSF marking (3PMSF stands for "3 Peak Mountain Snow Flake"). All-season tires, due to their performance on snow, also display the M+S and / or 3PMSF markings. Summer tires, however, do not have the M+S or 3PMSF markings.

[0049] Optionally, each cutout has a width ranging from 0.2 mm to 3.0 mm, preferably from 0.4 mm to 2.0 mm, more preferably from 0.4 mm to 1.0 mm.

[0050] Optionally, each cutout has a depth ranging from 2.0 mm to the carving height, preferably ranging from 4.0 mm to the carving height and more preferably ranging from 5.0 mm to the carving height.

[0051] In some embodiments, the first cut has a length along the circumferential direction strictly less than the length along the circumferential direction of the second cut, and: - the length of the first portion of the first cut is strictly greater than the length of the first portion of the second cut, and / or - the length of the second portion of the first cut is strictly less than the length of the second portion of the second cut, and / or - the length of the third portion of the first cut is strictly greater than the length of the third portion of the second cut.

[0052] Preferably, each first and second cut consists of the first, second, and third portions. In other words, for each cut comprising two ends, one end of the first portion coincides with one end of said cut, and one end of the third portion coincides with the other end of said cut.

[0053] In some embodiments, the first cut has a length along the axial direction, substantially equal to the length along the axial direction of the second cutout. This embodiment is particularly advantageous in the case where the circumferential rib in which the first and second cutouts are formed has a substantially constant length along the axial direction.

[0054] The length along the axial direction of said cut is equal to the distance along the axial direction between the two most distant points of said cut along the axial direction.

[0055] In advantageous but optional variations, to reduce the number of stamping tools required to manufacture the molding elements of the cutouts, the angle formed by the average direction of the first portion and the average direction of the second portion of each first and second cutout is substantially equal to the angle formed by the average direction of the second portion and the average direction of the third portion of each first and second cutout. Thus, in other words, the average direction of each third portion is substantially parallel to the average direction of each first portion.

[0056] In other, less advantageous and optional variants, the angle formed by the average direction of the first portion and the average direction of the second portion of each first and second cut is different from the angle formed by the average direction of the second portion and the average direction of the third portion of each first and second cut. Thus, in other words, the average direction of each third portion is not parallel to the average direction of each first portion.

[0057] An even more preferred method that simplifies the design of stamping tools: - the length of the first portion of the first cut is equal to the length of the third portion of the first cut, and / or - the length of the first portion of the second cut is equal to the length of the third portion of the second cut.

[0058] In some embodiments, the first and second cuts are circumferentially adjacent.

[0059] Optionally, in order to limit the siren noise, the cutouts include a third cutout, the third cutout comprising first, second and third portions, the first and second portions of the third cutout being directly joined to each other by a first inflection zone, the second and third portions of the third cutout being directly joined to each other. the other by a second inflection zone, the second portion of the third cut being arranged axially between the first and third portions of the third cut, the average direction of the first portion of the third cut being not parallel to the average direction of the second portion of the third cut, the average direction of the third portion of the third cut is not parallel to the average direction of the second portion of the third cut, the third cut having a length along the circumferential direction different from the length along the circumferential direction of each of the first and second cuts, the third cut opens into each of the first and second circumferential cuts delimiting said circumferential rib in respectively first and second opening zones,The azimuth of a point in the first outlet zone of the third cutout is substantially circumferentially aligned with the azimuth of a point in the second outlet zone of one of the first and second cutouts; an angle formed by the average direction of the first portion and the average direction of the second portion of the third cutout is substantially equal to the angle formed by the average direction of the first portion and the average direction of the second portion of each first and second cutout; an angle formed by the average direction of the second portion and the average direction of the third portion of the third cutout is substantially equal to the angle formed by the average direction of the second portion and the average direction of the third portion of each first and second cutout.the first portion of the third cut extends along an average direction substantially parallel to the average direction along which the first portion of each first and second cut extends, and the second portion of the third cut extends along an average direction substantially parallel to the average direction along which the second portion of each first and second cut extends, the third portion of the third cut extends along an average direction substantially parallel to the average direction along which the third portion of each first and second cut extends, and the length of the first portion of each first, second, and third cut is different from the length of the first portion of each other cut taken from the first, second, and third cuts, and / or the length of the second, portion of each first, second and third cut is different from the length of the second portion of each other cut taken from the first, second and third cuts, and / or the length of the third portion of each first, second and third cut is different from the length of the third portion of each other cut taken from the first, second and third cuts.

[0060] In some embodiments, the first cut has a length along the circumferential direction strictly less than the length along the circumferential direction of the second cut, and the second cut has a length along the circumferential direction strictly less than the length along the circumferential direction of the third cut, and: - the length of the first portion of the first cut is strictly greater than the length of the first portion of the second cut, and the length of the first portion of the second cut is strictly greater than the length of the first portion of the third cut, and / or - the length of the second portion of the first cut is strictly less than the length of the second portion of the second cut, and the length of the second portion of the second cut is strictly less than the length of the second portion of the third cut, and / or - the length of the third portion of the first cut is strictly greater than the length of the third portion of the second cut and the length of the third portion of the second cut is strictly greater than the length of the third portion of the third cut.

[0061] Preferably, the third cut consists of the first, second and third portions.

[0062] In some embodiments, the third cutout has a length along the axial direction substantially equal to the length along the axial direction of each of the first and second cutouts. This embodiment is particularly advantageous when the circumferential rib in which the first, second, and third cutouts are formed has a substantially constant length along the axial direction.

[0063] In advantageous but optional variants, in order to reduce the number of stamping tools required to manufacture the molding elements of the cutouts comprising first, second, and third portions, an angle formed by the average direction of the first portion and the average direction of the second portion of the third cutout is substantially equal to an angle formed by the direction average of the second portion and the average direction of the third portion of the third cut.

[0064] In other less advantageous and optional variants, an angle formed by the average direction of the first portion and the average direction of the second portion of the third cut is different from an angle formed by the average direction of the second portion and the average direction of the third portion of the third cut.

[0065] An even more preferred method that simplifies the design of stamping tools: - the length of the first portion of the first cut is equal to the length of the third portion of the first cut, and / or - the length of the first portion of the second cut is equal to the length of the third portion of the second cut, and / or - the length of the first portion of the third cut is equal to the length of the third portion of the third cut.

[0066] In some embodiments, the third cutout is circumferentially adjacent to at least one of the first and second cutouts. Preferably, each first, second, and third cutout is circumferentially adjacent to at least one other cutout taken from among the first, second, and third cutouts.

[0067] Optionally and preferably, each first and second circumferential cut has a depth greater than or equal to 50%, preferably 75% and more preferably 90% of the sculpture height.

[0068] Optionally and preferably, each first and second circumferential cut has a depth ranging from 4.0 mm to the carving height, preferably from 5.0 mm to the carving height and more preferably from 5.5 mm to the carving height.

[0069] Optionally and preferably, each first and second circumferential cutout has a width greater than or equal to 1.0 mm, preferably greater than or equal to 4.0 mm and more preferably ranging from 4.0 mm to 20.0 mm.

[0070] In preferred embodiments, each cut has a mean direction forming an angle greater than or equal to 45° with the circumferential direction of the tire. The mean direction of the cut is the direction along which the straight line joining the two ends of the cut extends.

[0071] Conventionally, a tire consists of a crown, two sidewalls, and two beads, with each sidewall connecting each bead to the crown. Always in this way In a conventional design, the crown comprises the tread and a crown reinforcement arranged radially within the tread. The tire also includes a carcass reinforcement anchored in each bead and extending radially into each sidewall and axially into the crown, radially internal to the crown reinforcement.

[0072] Conventionally, the top reinforcement comprises at least one top layer containing reinforcing elements. These reinforcing elements are preferably textile or metallic wire elements.

[0073] In embodiments enabling the performance of so-called radial tires, for example as defined by ETRTO, the carcass reinforcement comprises at least one carcass layer, the or each carcass layer comprising wire carcass reinforcement elements, each wire carcass reinforcement element extending substantially along a principal direction forming with the circumferential direction of the tire, an angle, in absolute value, ranging from 80° to 90°.

[0074] The invention will be better understood upon reading the following description, given solely by way of non-limiting example and made with reference to the drawings in which: - Figure 1 is a top view of the tread of a tire according to a first embodiment of the invention, - Figure 2 is a schematic view of part of the tread of the tire in Figure 1, illustrating the first, second, and third cuts, and - Figures 3, 4 and 5 illustrate respectively each first, second and third cutouts of figure 2.

[0075] We have represented a coordinate system X, Y, Z corresponding to the usual directions respectively axial (Y), radial (Z) and circumferential (X) of a tire.

[0076] With reference to Figure 1, the tire according to the invention is designated by the general reference numeral 10. Tire 10 has a substantially toroidal shape around an axis of revolution substantially parallel to the axial direction Y. Tire 10 is intended for a passenger vehicle and has dimensions 205 / 55 R16. Tire 10 is a summer tire. Tire 10 is shown in its new condition, i.e., having not yet been driven on.

[0077] The tire 10 includes a tread 14 intended to come into contact with the ground during rolling. The tire 10 also includes a conventional structure, such as, for example, described in the applications WO2021250331, WO2022074341 or WO2022069819. The tire 10 is obtained by molding a raw blank in a mold comprising molding elements, including tread molding elements 14.

[0078] The tread 14 includes a tread surface 16 through which the tread 14 is intended to come into contact with the ground when the tire 10 is rolling over the ground.

[0079] The tread 14 comprises an axially central portion PO and first and second axially lateral portions P1, P2 arranged axially outside the axially central portion PO and axially on either side of the axially central portion PO with respect to the median plane M of the tire 10.

[0080] The tread 14 comprises N>1 circumferential cutouts, here N=4 circumferential cutouts designated by references 20, 22, 24, 26. Each circumferential cutout 20 to 26 has a depth ranging 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. Each depth is greater than or equal to 50%, preferably 75%, and more preferably 90% of the tread height. Here, Hs=7.2 mm, the depth of each circumferential cutout 20, 26 being equal to 7.0 mm and the depth of each circumferential cutout 22, 24 being equal to 7.2 mm.

[0081] Each circumferential cutout 20 to 26 has a width greater than or equal to 1.0 mm, preferably greater than or equal to 4.0 mm and more preferably ranging from 4.0 mm to 20.0 mm. Here, the width of each circumferential cutout 20 to 26 is equal to 11.0 mm.

[0082] The axially central portion PO comprises k>1 circumferential ribs, here k=3 circumferential ribs 28, 30, 32. Each circumferential rib 28 to 32 is axially delimited by first and second axially adjacent circumferential cutouts among the circumferential cutouts 20 to 26. Each circumferential rib 28 to 32 has a substantially constant length along the axial direction.

[0083] Each circumferential rib 28, 30, 32 comprises transverse cutouts formed in said central rib 28, 30, 32 and respectively designated by reference numerals 38, 40, 42. Thus, the cutouts 38 are formed in the same circumferential rib 28, the cutouts 40 are formed in the same circumferential rib 30, and the cutouts 42 are formed in the same circumferential rib 32. Each cutout 38 opens into each of the circumferential cutouts 20, 22. Each cutout 40 opens into each of the cutouts circumferential 22, 24. Each cutout 42 opens into each of the circumferential cutouts 24, 26.

[0084] Each cut 38, 40, 42 has a mean direction forming an angle greater than or equal to 45° with the circumferential direction X of the tire 10. Each cut 38, 40, 42 has a width ranging from 0.2 mm to 3.0 mm, preferably from 0.4 mm to 2.0 mm, more preferably from 0.4 mm to 1.0 mm, and here equal to 0.4 mm. Each cut 38, 40, 42 has a depth ranging from 2.0 mm to the tread height Hs, preferably from 4.0 mm to the tread height Hs, and more preferably from 5.0 mm to the tread height Hs, and here equal to 5.5 mm.

[0085] Figure 2 shows first, second, and third cutouts 40 designated respectively by reference numerals 402, 404, and 406 formed in the circumferential rib 28 delimited by the circumferential cutouts 20, 22. The first cutout 402 is circumferentially adjacent to the second cutout 404. The second cutout 404 is circumferentially adjacent to each of the first and third cutouts 402, 406. The third cutout 406 is circumferentially adjacent to the second cutout 404. Each first, second, and third cutout 40 comprises two ends I and J.

[0086] Each first cut 402 has a length 11 along the axial direction Y approximately equal to the length I2 along the axial direction Y of each second cut 404 and approximately equal to the length I3 along the axial direction Y of each third cut 406. Here 11=12=13=28 mm.

[0087] Each first cutout 402 has a length L1 along the circumferential direction X that is different from the length L2 along the circumferential direction X of each second cutout 404. Each second cutout 404 has a length L2 along the circumferential direction X that is different from the length L3 along the circumferential direction X of each third cutout 406. Each first cutout 402 has a length L1 along the circumferential direction X that is different from the length L3 along the circumferential direction X of each third cutout 406. Here, L1 = 16.3 mm, L2 = 17.9 mm, and L3 = 23.1 mm.

[0088] Each cutout 402, 404, 406 opens into each of the circumferential cutouts 20, 22 in the first and second opening zones Z1, Z2, respectively. The azimuth AZ1 of a point in the first opening zone AZ1 of a cutout 402, 404, 406 formed in the circumferential rib 28, here end I, is substantially circumferentially aligned with the azimuth AZ2 of a point in the second opening zone AZ2 of another circumferentially adjacent cutout 402, 404, 406 formed in the circumferential rib 28, here end J of another cutouts 402, 404, 406 circumferentially adjacent and made in the circumferential rib 28.

[0089] Each first cut 402 comprises, here, the first, second, and third portions 4021, 4022, and 4023. Each second cut 404 comprises, here, the first, second, and third portions 4041, 4042, and 4043. Each third cut 406 comprises, here, the first, second, and third portions 4061, 4062, and 4063. Each second portion 4022, 4042, 4062 is arranged axially between the corresponding first portion 4021, 4041, 4061 and third portion 4023, 4043, 4063. Each first portion 4021, 4041, 4061 and each second portion 4022, 4042, 4062 are directly joined to each other respectively by a first inflection zone 4024, 4044, 4064. Each second portion 4022, 4042, 4062 and each third portion 4023, 4043, 4063 are directly joined to each other respectively by a second inflection zone 4025, 4045, 4065.

[0090] As can be seen in Figures 3 to 5, the length L21 of the first portion 4021 of each first cutout 402 is different from the length L41 of the first portion 4041 of each second cutout 404 and from the length L61 of the first portion 4061 of each third cutout 406. The length L21 of the first portion 4041 of each second cutout 404 is different from the length L61 of the first portion 4061 of each third cutout 406. Here, L21 > L41 > L61 and more precisely L21 = 9.41 mm, L41 = 8.75 mm, L61 = 6.53 mm.

[0091] The length L22 of the second portion 4022 of each first cut 402 is different from the length L42 of the second portion 4042 of each second cut 404 and from the length L62 of the second portion 4062 of each third cut 406. The length L42 of the second portion 4042 of each second cut 404 is different from the length L62 of the second portion 4062 of each third cut 406. Here, L22 <L42<L62 et plus précisément L22=16,11 mm, L42=18,35 mm, L62=25,75 mm.

[0092] The length L23 of the third portion 4023 of each first cut 402 is different from the length L43 of the third portion 4043 of each second cut 404 and from the length L63 of the third portion 4063 of each third cut 406. The length L43 of the third portion 4043 of each second cut 404 is different from the length L63 of the third portion 4063 of each third cut 406. Here, L23 > L43 > L63 and more precisely L23 = 9.41 mm, L43 = 8.75 mm, L63 = 6.53 mm.

[0093] Note that the length L21 of each first portion 4021 of each The length of the first cut 402 is equal to the length L23 of each third portion 4023 of each first cut 402. It should also be noted that the length L41 of each first portion 4041 of each second cut 404 is equal to the length L43 of each third portion 4043 of each second cut 404. Finally, it should be noted that the length L61 of each first portion 4061 of each third cut 406 is equal to the length L63 of each third portion 4063 of each third cut 406.

[0094] Each first, second, and third portion 4021, 4022, 4023 of the first cut 402 extends respectively along a first, second, and third average direction D21, D22, D23. Each first, second, and third portion 4041, 4042, 4043 of the second cut 404 extends respectively along a first, second, and third average direction D41, D42, D43. Each first, second, and third portion 4021, 4022, 4023 of the third cut 406 extends respectively along a first, second, and third average direction D61, D62, D63.

[0095] The average direction D21, D41, D61 of each first portion 4021, 4041, 4061 and the average direction D23, D43, D63 of each third portion 4023, 4043, 4063 of each first, second and third cut 402, 404, 406 is not parallel to the average direction D22, D42, D62 of the second portion 4022, 4042, 4062 respectively of each first, second and third cut 402, 404, 406.

[0096] The average directions D21, D41, and D61 are substantially parallel to each other. The average directions D22, D42, and D62 are substantially parallel to each other. The average directions D23, D43, and D63 are substantially parallel to each other.

[0097] The average direction D21 of the first segment 4021 and the average direction D22 of the second segment 4022 of the first cut 402 form an angle A2. The average direction D41 of the first segment 4041 and the average direction D42 of the second segment 4042 of the second cut 404 form an angle A4. The average direction D61 of the first segment 4061 and the average direction D62 of the second segment 4062 of the third cut 406 form an angle A6.

[0098] The average direction D22 of the second segment 4022 and the average direction D23 of the third segment 4023 of the first segment 402 form an angle B2. The average direction D42 of the second segment 4042 and the average direction D43 of the third segment 4043 of the second segment 404 form an angle B4. The average direction D62 of the second segment 4062 and the average direction D63 of the third segment 4063 of the third segment 406 form an angle B6.

[0099] Angles A2, A4, and A6 are approximately equal. Angles B2, B4, and B6 are approximately equal to each other and approximately equal to angles A2, A4, A6. Here, A2=A4=A6= B2= B4= B6=54°.

[0100] The characteristics of the cutouts 42 are identical to those of the cutouts 40 described above. The characteristics of the cutouts 38 are deduced mutatis mutandis from those of the cutouts 40 described above by reversing them with respect to a plane perpendicular to the axis of rotation of the tire, parallel to the median plane M and passing through the circumferential cutout 20.

Claims

CLAIMS 1. A tire (10) comprising a tread (14) comprising at least one circumferential rib (28, 30, 32) delimited by first and second circumferential cutouts (20, 22, 24, 26) and cutouts (38, 40, 42) formed in said circumferential rib and opening into each of the first and second circumferential cutouts, the cutouts (38, 40, 42) comprising first and second cutouts (402, 404), each first and second cutout (402, 404) comprises first (4021, 4041), second (4022, 4042) and third portions (4023, 4043), the first portion (4021, 4041) and the second portion (4022, 4042) of each first and second cutout (402, 404) being joined directly to each other by a first inflection zone (4024, 4044), the second portion (4022, 4042) and the third portion (4023, 4043) of each first and second cutout (402,404) being joined directly to each other by a second inflection zone (4025, 4045), the second portion (4022, 4042) of each first and second cutout (402, 404) being arranged axially between the first (4021, 4041) and third (4023, 4043) portions respectively of each first and second cutout (402, 404), the mean direction (D21, D41) of the first portion (4021, 4041) of each first and second cutout (402, 404) being non-parallel to the mean direction (D22, D42) of the second portion (4022, 4042) respectively of each first and second cutout (402, 404), the mean direction (D23, D43) of the third portion (4023, 4043) of each first and second cutout (402, 404) is non-parallel to the mean direction (D22, D42) of the second portion (4022, 4042) respectively of each first and second cutout (402, 404),the first cutout (402) having a length (L1) in the circumferential direction (X) different from the length (L2) in the circumferential direction (X) of the second cutout (404), each first and second cutout (402, 404) opens into each of the first and second circumferential cutouts (20, 22, 24, 26) delimiting said circumferential rib (28, 30, 32) in respectively first and second opening zones (Z1, Z2), the azimuth (AZ1) of a point of the first opening zone (Z1) of the first cutout is substantially circumferentially aligned with the azimuth (AZ2) of a point of the second opening zone (Z2) of the second cutout, an angle (A2) formed by the mean direction (D21) of the first portion (4021) and the mean direction (D22) of the second portion (4022) of the first cutout (402) is, substantially equal to an angle (A4) formed by the mean direction (D41) of the first portion (4041) and the mean direction (D42) of the second portion (4042) of the second cutout (404), an angle (B2) formed by the mean direction (D22) of the second portion (4022) and the mean direction (D23) of the third portion (4023) of the first cutout (402) is substantially equal to an angle (B4) formed by the mean direction (D42) of the second portion (4042) and the mean direction (D43) of the third portion (4043) of the second cutout (404), the first portion (4021) of the first cutout (402) extends in a mean direction (D21) substantially parallel to the mean direction (D41) in which the first portion (4041) of the second cutout extends (404),the second portion (4022) of the first cutout (402) extends in a mean direction (D22) substantially parallel to the mean direction (D42) in which the second portion (4042) of the second cutout (404) extends, the third portion (4023) of the first cutout (402) extends in a mean direction (D23) substantially parallel to the mean direction (D43) in which the third portion (4043) of the second cutout (404) extends,and the length (L21) of the first portion (4021) of the first cutout (402) is different from the length (L41) of the first portion (4041) of the second cutout (404) and / or the length (L22) of the second portion (4022) of the first cutout (402) is different from the length (L42) of the second portion (4042) of the second cutout (404) and / or the length (L23) of the third portion (4023) of the first cutout (402) is different from the length (L43) of the third portion (4043) of the second cutout (404)., 2. Tire (10) according to the preceding claim, in which the first cutout (402) has a length (L1) in the circumferential direction strictly less than the length (L2) in the circumferential direction of the second cutout (404), and: - the length (L21) of the first portion (4021) of the first cutout (402) is strictly greater than the length (L41) of the first portion (4041) of the second cutout (404), and / or - the length (L22) of the second portion (4022) of the first cutout (402) is strictly less than the length (L42) of the second portion (4042) of the second cutout (404), and / or - the length (L23) of the third portion (4023) of the first cutout (402) is strictly greater than the length (L43) of the third portion (4043) of the second cutout (404).

3. Tire (10) according to any one of the preceding claims, in which the first cutout (402) has a length (11) in the axial direction (Y) substantially equal to the length (12) in the axial direction (Y) of the second cutout (404).

4. A tire (10) according to any one of the preceding claims, wherein an angle (A2, A4) formed by the mean direction (D21, D41) of the first portion (4021, 4041) and the mean direction (D22, D42) of the second portion (4022, 4042) of each first and second cutout (402, 404) is substantially equal to an angle (B2, B4) formed by the mean direction (D22, D42) of the second portion (4022, 4042) and the mean direction (D23, D43) of the third portion (4023, 4043) of each first and second cutout (402, 404).

5. A tire (10) according to any preceding claim, wherein: - the length (L21) of the first portion (4021) of the first cutout (402) is equal to the length (L23) of the third portion (4023) of the first cutout (402), and / or - the length (L41) of the first portion (4042) of the second cutout (404) is equal to the length (L43) of the third portion (4043) of the second cutout (404).

6. A tire (10) according to any preceding claim, wherein the first and second cutouts (402, 404) are circumferentially adjacent.

7. A tire (10) according to any preceding claim, wherein the cutouts (38, 40, 42) comprise a third cutout (406), the third cutout (406) comprising first, second and third portions (4061, 4062, 4063), the first portion (4061) and the second portion (4062) of the third cutout (406) being joined directly to each other by a first inflection zone (4064), the second portion (4062) and the third portion (4063) of the third cutout (406) being joined directly to each other by a second inflection zone (4065), the second portion (4062) of the third cutout (406) being arranged axially between the first and third portions (4061, 4063) of the third cutout (406). cutting (406), the mean direction (D61) of the first portion (4061) of the third cutout (406) being non-parallel to the mean direction (D62) of the second portion (4062) of the third cutout (406), the mean direction (D63) of the third portion (4063) of the third cutout (406) is non-parallel to the mean direction (D62) of the second portion (4062) of the third cutout (406), the third cutout (406) having a length (L3) in the circumferential direction (X) different from the length (L1, L2) in the circumferential direction (X) of each first and second cutout (402, 404), the third cutout (406) opens into each of the first and second circumferential cutouts (20, 22, 24, 26) delimiting said rib circumferential (28, 30, 32) in respectively first and second outlet zones (Z1, Z2),the azimuth (AZ1) of a point of the first outlet zone (Z1) of the third cutout (406) is substantially circumferentially aligned with the azimuth (AZ2) of a point of the second outlet zone (Z2) of one of the first and second cutouts (402, 404), an angle (A6) formed by the mean direction (D61) of the first portion (4061) and the mean direction (D62) of the second portion (4062) of the third cutout (406) is substantially equal to each angle (A2, A4) formed by the mean direction (D21, D41) of the first portion (4021, 4041) and the mean direction (D22, D42) of the second portion (4022, 4042) of each first and second cutout (402, 404), an angle (B6) formed by the mean direction (D62) of the second portion (4062) and the mean direction (D63) of the third portion (4063) of the third cutout (406) is substantially equal to the angle (B2, B4) formed by the mean direction (D22, D42) of the second portion (4022,4042) and the mean direction (D23, D43) of the third portion (4043) of each first and second cutout (402, 404), the first portion (4061) of the third cutout (406) extends in a mean direction (D61) substantially parallel to the mean direction (D21, D41) in which the first portion (4021, 4041) of each first and second cutout (402, 404) extends, the second portion (4062) of the third cutout (406) extends in a mean direction (D62) substantially parallel to the mean direction (D22, D42) in which the second portion (4022, 4042) of each first and second cutout (402, 404) extends, the third portion (4063) of the third cutout (406) extends along a mean direction (D63) substantially parallel to the mean direction (D23, D43) along which, extends the third portion (4023, 4043) of each first and second cutout (402, 404), and the length (L21, L41, L61) of the first portion (4021, 4041, 4061) of each first, second and third cutout (402, 404, 406) is different from the length (L21, L41, L61) of the first portion (4021, 4041, 4061) of each other cutout taken from among the first, second and third cutouts (402, 404, 406), and / or the length (L22, L42, L62) of the second portion (4022, 4042, 4062) of each first, second and third cutout (402, 404, 406) is different from the length (L22, L42, L62) of the second portion (4022, 4042, 4062) of each other cutout taken from among the first, second and third cutouts (402, 404, 406), and / or the length (L23, L43, L63) of the third portion (4023, 4043, 4063) of each first, second and third cutout (402, 404, 406) is different from the length (L23, L43, L63) of the third portion (4023, 4043,4063) of each other cutout taken from among the first, second and third cutouts (402, 404, 406)., 8. Tire (10) according to the preceding claim, in which the first cutout (402) has a length (L1) in the circumferential direction strictly less than the length (L2) in the circumferential direction of the second cutout (404) and the second cutout (404) has a length (L2) in the circumferential direction strictly less than the length (L3) in the circumferential direction of the third cutout (406), and: - the length (L21) of the first portion (4021) of the first cutout (402) is strictly greater than the length (L41) of the first portion (4041) of the second cutout (404) and the length (L41) of the first portion (4041) of the second cutout (404) is strictly greater than the length (L61) of the first portion (4061) of the third cutout (406), and / or - the length (L22) of the second portion (4022) of the first cutout (402) is strictly less than the length (L42) of the second portion (4042) of the second cutout and the length (L42) of the second portion (4042) of the second cutout (404) is strictly less than the length (L62) of the second portion (4062) of the third cutout (406), and / or - the length (L23) of the third portion (4023) of the first cutout (402) is strictly greater than the length (L43) of the third portion (4043) of the second cutout (404) and the length (L43) of the third portion (4043) of the second cutout (404) is strictly greater than the length (L63) of the third portion (4063) of the third cutout (406).

9. Tire (10) according to claim 7 or 8, in which the third cutout (406) has a length (I3) in the axial direction (Y) substantially equal to the length (I1, I2) in the axial direction (Y) of each first (402) and second cutout (404).

10. Tire (10) according to any one of claims 7 to 9, wherein an angle (A6) formed by the mean direction (D61) of the first portion (4061) and the mean direction (D62) of the second portion (4062) of the third cutout (406) is substantially equal to an angle (B6) formed by the mean direction (D62) of the second portion (4062) and the mean direction (D63) of the third portion (4063) of the third cutout (406).

11. A tire (10) according to any one of claims 7 to 10, wherein: - the length (L21) of the first portion (4021) of the first cutout (402) is equal to the length (L23) of the third portion (4023) of the first cutout (402), and / or - the length (L41) of the first portion (4041) of the second cutout (404) is equal to the length (L43) of the third portion (4043) of the second cutout (404), and / or - the length (L61) of the first portion (4061) of the third cutout (406) is equal to the length (L63) of the third portion (4063) of the third cutout (406).

12. A tire (10) according to any one of claims 7 to 11, wherein the third cutout (406) is circumferentially adjacent to at least one of the first and second cutouts (402, 404), preferably each first, second and third cutout (402, 404, 406) is circumferentially adjacent to at least one other cutout taken from among the first, second and third cutouts (402, 404,

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