Tyre comprising shoulders comprising a linear density of cuts of measurable depth

Abstract

The invention relates to a tyre (10) comprising a tread (14) comprising a total number of transverse cuts (48, 50) arranged in the axially lateral portion (P1, P2). At least one and at most 30% of the total number of transverse cuts (48, 50) are referred to as indicative transverse cuts (482, 502) having, in a portion referred to as an indicative portion (4821, 5021), a minimum width strictly greater than 1.5 mm, while the remainder of the total number of transverse cuts (48, 50) are referred to as common transverse cuts (481, 501) having a maximum width of 1.5 mm or less. The linear density DI1 of one or more indicative transverse cuts (482, 502) satisfies DI1 ≤ 0.15 cm-1.

Description

Pneumatic comprising shoulders comprising a linear density of cutouts with measurable depth

[0001] The present invention relates to a tire, in particular for a passenger vehicle. By tire is meant a bandage intended to form a cavity by cooperating with a support element, for example a rim, this cavity being capable of being pressurized to a pressure higher than atmospheric pressure. A tire according to the invention has a structure of substantially toroidal shape of revolution around a main axis of the tire.

[0002] Known from the state of the art are tires comprising a tread comprising main circumferential cutouts having a depth greater than or equal to 50% of the tread height and comprising first and second axially outer main circumferential cutouts arranged axially on either side of the median plane of the tire. The first and second axially outer main circumferential cutouts are the axially outermost main circumferential cutouts of the tread.

[0003] The tread comprises an axially central portion, a first axially lateral portion arranged axially outside the first axially outer main circumferential cutout and a second axially lateral portion arranged axially outside the second axially outer main circumferential cutout. The tread also comprises first and second transverse cutouts formed respectively in each first and second axially lateral portion.

[0004] Depending on the desired performance, each first and second transverse cut may have a greater or lesser width. For example, tires with low rolling resistance have first and second transverse cuts with a width less than or equal to 1.5 mm.

[0005] Furthermore, in order to comply with regulatory obligations, the tire includes several wear indicators distributed circumferentially on the tire and positioned in each of the main circumferential cutouts. Thus, an individual, for example the owner of the vehicle on which the tire is mounted, as well as a professional, for example a specifier, a technical inspector or a law enforcement officer, can visually check whether the wear of the tire has reached, in the axially central portion, a level of wear requiring its replacement.

[0006] However, on the one hand, there is no way to visually determine the level of wear of the tire in the first and second axially lateral portions in which no wear indicator is arranged. On the other hand, professionals, in particular those mentioned above, may want to measure the depth of the tread in the first and second axially lateral portions in order to check whether this thickness is sufficient. However, the presence of first and second transverse cutouts having a width less than or equal to 1.5 mm prevents the measurement of this thickness, whether it is done by means of a laser device or by means of a depth measuring gauge.

[0007] The aim of the invention is to enable the measurement of the depth of the tread on at least one of the first and second axially lateral portions without altering the performance for which it is necessary to have relatively fine transverse cutouts.

[0008] To this end, the invention relates to a tire comprising a tread comprising: - main circumferential cutouts having a depth greater than or equal to 50% of the tread height comprising at least one axially outer main circumferential cutout, the axially outer main circumferential cutout being, on one side of a median plane of the tire, the axially outermost main circumferential cutout of the tread, - at least one axially lateral portion arranged axially outside the axially outer main circumferential cutout, the tread comprising a total number of transverse cutouts arranged in said axially lateral portion, at least one and at most 30% of the total number of transverse cutouts is one or are so-called indicative transverse cutout(s), having, on a so-called indicative portion, a minimum width strictly greater than 1.5 mm and the remainder of the total number of transverse cutouts are so-called common transverse cutouts, having a maximum width less than or equal to 1.5 mm, the linear density DI1 of the indicative transverse cutout(s) being defined by the ratio of the total number of indicative transverse cutout(s) arranged at least partly in the axially lateral portion to the circumference of the tire measured on the median plane and inflated to 2,5 bars, DI1 satisfies DI1 < 0.15 cm- 1.,

[0009] Thus, the depth of the axially lateral portion can be measured using the indicative portion without altering the performance for which it is intended. necessary to have relatively fine transverse cutouts. The indicative transverse cutout is called indicative due to the presence of the indicative portion which has an indicative function of the tread depth at the indicative portion.

[0010] Indeed, due to the relatively high minimum width, the indicative portion allows the measurement of the depth in the axially lateral portion, in particular by means of a laser device or by means of a depth measuring gauge. In order not to impair the performance for which it is necessary to have relatively fine transverse cutouts, the inventors have reduced the number of indicative transverse cutout(s). At least one indicative transverse cutout is essential in order to guarantee the possibility of finding an indicative portion on the circumference of the tire.

[0011] The indicative cross-section(s) and the common cross-sections are distinct from each other. Thus, an indicative cross-section cannot be a common cross-section and a common cross-section cannot be an indicative cross-section.

[0012] The total number of transverse cutouts is the total number of transverse cutouts provided in the corresponding axially lateral portion. Thus, if a total number of N transverse cutouts are provided in the axially lateral portion and, among these N transverse cutouts provided in the axially lateral portion, Ni transverse cutout(s) is / are indicative transverse cutout(s), Nc=N-Ni common transverse cutouts are provided in the axially lateral portion. In other words, N=Ni+Nc.

[0013] The number of indicative transverse cutout(s) used to calculate the linear density of indicative transverse cutout(s) is the total number of indicative transverse cutout(s) provided in the corresponding axially lateral portion. Similarly, the number of common transverse cutouts used to calculate the linear density of common transverse cutouts is the total number of common transverse cutouts provided in the corresponding axially lateral portion.

[0014] A cutout or a portion of a cutout has two main characteristic dimensions: a width and a curvilinear length such that the curvilinear length is at least twice the width. A cutout or a portion of a cutout is therefore delimited by at least two main lateral faces determining its curvilinear length and connected by a base, the two main lateral faces being distant from each other by a non-zero distance, called the width of the cutout or the cutout portion. Unless otherwise stated, the width of a cutout or cutout portion is the maximum width of the cutout or cutout portion.

[0015] The principal direction of a cut is the direction along which the curve passes equidistant from each of the edges of the cut to the radial dimension of the rolling surface. The curvilinear length is the length measured along this curve equidistant from each of the edges of the cut to the radial dimension of the rolling surface, and this between each end of the cut.

[0016] The minimum width of a cut or portion of a cut is, on a new tire, the smallest distance between the two main side faces measured over the entire depth of the cut or portion. The minimum width is measured substantially perpendicular to the main side faces.

[0017] The maximum width of a cutout or portion of a cutout is, in the case where the cutout or portion of a cutout does not include a chamfer, on a new tyre, the greatest distance between the two main lateral faces measured over the entire depth of the cutout or portion. The maximum width of a cutout or portion of a cutout is, in the case where the cutout or portion of a cutout includes a chamfer, on a new tyre, the greatest distance between the two main lateral faces measured over the entire depth of the cutout or portion radially inside the chamfer. The maximum width is measured substantially perpendicular to the main lateral faces.

[0018] The depth of a cut or a portion of a cut is, on a new tire, the maximum radial distance between the bottom of the cut or portion and its projection onto the ground when the tire is rolling. The maximum value of the depths of the cuts is called the tread height.

[0019] A cutout or portion of a cutout may be transverse or circumferential.

[0020] A transverse cut is such that the cut extends in 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 or portion may be continuous, i.e. not interrupted by a tread block or another cut so that the two main lateral faces determining its length are uninterrupted along the length of the transverse cut or portion. A transverse cut may also be discontinuous, i.e. interrupted by one or more sculpture blocks and / or one or more cuts so that the two main lateral faces determining its length are interrupted by one or more sculpture blocks and / or one or more cuts.

[0021] A circumferential cutout is such that the cutout or portion extends in a mean direction forming an angle less than or equal to 30°, preferably less than or equal to 10° 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 cutout and parallel to the rolling surface. In the case of a continuous circumferential cutout, the two ends coincide with each other and are joined by a curve making a complete turn of the tire. A circumferential cutout may be continuous, i.e. not be interrupted by a tread block or another cutout so that the two main lateral faces determining its length are uninterrupted over the entire turn of the tire.A circumferential cutout may also be discontinuous, i.e. interrupted by one or more tread blocks and / or one or more cutouts so that the two main lateral faces determining its length are interrupted by one or more tread blocks and / or one or more cutouts over the entire circumference of the tire.

[0022] In embodiments for optionally improving braking on dry ground, the or each transverse cutout is provided with chamfers. A chamfer of a transverse cutout may 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 which it extends to the leading or trailing edge circumferentially delimiting the transverse cutout. A rounded chamfer is formed by a curved face connecting tangentially to the leading or trailing face which it extends. A chamfer of a transverse cutout is characterized by a height and a width respectively equal to the radial distance and to the distance in a direction perpendicular to the leading or trailing faces between the common point between the leading or trailing face extended by the chamfer and the leading or trailing edge circumferentially delimiting the transverse cutout.

[0023] The tire according to the invention has a substantially toric shape around an axis of revolution substantially coincident 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.

[0024] Axial direction means the direction substantially parallel to the axis of revolution of the tire, i.e. the axis of rotation of the tire.

[0025] Circumferential direction means the direction which is substantially perpendicular to both the axial direction and a radius of the tire (in other words, tangent to a circle whose center is on the axis of rotation of the tire).

[0026] Radial direction means the direction along a radius of the tire, that is to say any direction intersecting the axis of rotation of the tire and substantially perpendicular to this axis.

[0027] By median plane of the tire (noted M), we mean the plane perpendicular to the axis of rotation of the tire which is located at the axial midpoint of the two beads and passes through the axial center of the crown reinforcement.

[0028] By equatorial circumferential plane of the tire, we mean, in a meridian section plane, the plane passing through the equator of the tire, perpendicular to the median plane and to the radial direction. The equator of the tire is, in a meridian section plane (plane perpendicular to the circumferential direction and parallel to the radial and axial directions) the axis parallel to the axis of rotation of the tire and located equidistant between the radially outermost point of the tread intended to be in contact with the ground and the radially innermost point of the tire intended to be in contact with a support, for example a rim.

[0029] Meridian plane means a plane parallel to and containing the axis of rotation of the tire and perpendicular to the circumferential direction.

[0030] By radially inner, respectively radially outer, is meant closer to the tire's axis of rotation, respectively further from the tire's axis of rotation. By axially inner, respectively axially outer, is meant closer to the tire's median plane, respectively further from the tire's median plane.

[0031] By bead is meant the portion of the tire intended to allow the tire to be attached to a mounting support, for example a wheel comprising a rim. Thus, each bead is in particular intended to be in contact with a hook on the rim allowing it to be attached.

[0032] Any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​from more than a to less than b (i.e., excluding the limits a and b), while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​from a to b (i.e., including the strict limits a and b).

[0033] The tires are, in preferred embodiments of the invention, intended for passenger vehicles as defined within the meaning of the European Tyre and Rim Technical Organization or "ETRTO" standard, 2023. Such a tire has a section in a meridian section plane characterized by a section height H and a nominal section width or bead thickness S within the meaning of the European Tyre and Rim Technical Organization or "ETRTO" standard, 2023 such that the H / S ratio, expressed as a percentage, is at most equal to 90, preferably at most equal to 70 and is at least equal to 30, and the nominal section width S is at least equal to 115 mm, preferably at least equal to 175 mm and at most equal to 385 mm, preferably at most equal to 315 mm. In addition, the diameter at hook D, defining the diameter of the tire mounting rim, is at least 12 inches, preferably at least 16 inches and at most 24 inches.

[0034] In embodiments in which the main circumferential cutouts are relatively deep, each main circumferential cutout has a depth ranging 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.

[0035] In embodiments in which the major circumferential cutouts are relatively deep, each major circumferential cutout has a depth greater than or equal to 75% of the tread height, preferably 90% of the tread height.

[0036] In embodiments in which the major circumferential cutouts are relatively wide major circumferential grooves, each major circumferential cutout has an axial width greater than or equal to 3.0 mm, preferably greater than or equal to 5.0 mm, and more preferably ranging from 5.0 mm to 20.0 mm.

[0037] In preferred embodiments, the indicative portion has a depth greater than or equal to 50%, preferably 75% of the tread height. The depth of the indicative portion will be adjusted by the tire designer so that the remaining depth of this portion is representative of the wear of the tire.

[0038] In preferred embodiments, each common transverse cutout has a depth greater than or equal to 50%, preferably 75% of the tread height.

[0039] In advantageous and optional embodiments, at least two of preferably at least six of the total number of transverse cutouts are indicative transverse cutouts. This makes it easier to find an indicative portion on the circumference of the tire.

[0040] In advantageous and optional embodiments, at most 20%, preferably at most 15% and more preferably at most 10% of the total number of transverse cutouts is one or are indicative transverse cutout(s). Even if the number of indicative transverse cutout(s) is sufficiently reduced so as not to impair the performance for which it is necessary to have relatively fine transverse cutouts, it is preferable to keep the number of the indicative transverse cutout(s) relatively low to reduce the risk of impairing the performance.

[0041] In advantageous and optional embodiments, DI1 < 0.13 cm-1, preferably DI1 < 0.10 cm-1, more preferably DI1 < 0.08 cm-1 and even more preferably DI1 < 0.05 cm-1.

[0042] In advantageous and optional embodiments, DI1 > 0.01 cm-1, preferably DI1 > 0.02 cm-1.

[0043] In advantageous and optional embodiments, the linear density DC1 of the common transverse cutouts being defined by the ratio of the total number of common transverse cutouts formed at least in part in the axially lateral portion on the circumference of the tire measured on the median plane and inflated to 2.5 bars, DC1 satisfies DC1 > 0.20 cm-1, preferably DC1 > 0.25 cm-1 and more preferably DC1 > 0.30 cm-1.

[0044] In advantageous and optional embodiments, DC1 < 1.40 cm-1.

[0045] In advantageous and optional embodiments applicable to so-called summer tires, DC1 < 0.60 cm-1, preferably DC1 < 0.50 cm-1 and more preferably DC1 < 0.40 cm-1.

[0046] Such a relatively low linear density DC1 is characteristic of summer tires for which performance is associated with a relatively small number of common transverse cutouts.

[0047] Summer tires are tires that are not so-called 4-season or all-season tires, nor so-called winter tires. A summer tire does not have an M+S marking or a 3PMSF marking.

[0048] In advantageous and optional embodiments applicable to so-called 4-season or all-season tires, DC1 satisfies 0.60 cm-1 < DC1 < 1.00 cm-1, preferably 0.70 cm-1 < DC1 < 0.90 cm-1.

[0049] Unlike summer tires, some tires have high performance on snowy ground, especially 4-season or all-season tires, and are characterized by a relatively high number of common transverse cuts. 4-season or all-season tires, due to their performance on snow, are notably identified by an M+S marking (M+S being the acronym for "Mud + Snow") and / or 3PMSF (3PMSF being the acronym for "3 Peak Mountain Snow Flake").

[0050] In advantageous and optional embodiments applicable to so-called winter tires, DC1 satisfies 1.00 cm-1 < DC1 < 1.40 cm-1, preferably 1.10 cm-1 < DC1 < 1.30 cm-1.

[0051] To ensure optimal performance on snowy surfaces, some tires, particularly winter tires, are characterized by a very high number of common transverse cuts. Winter tires are also identified by an M+S and / or 3PMSF marking.

[0052] In advantageous and optional embodiments, the indicative portion of each indicative transverse cutout has a minimum width less than or equal to 5.0 mm, preferably 3.5 mm and more preferably 2.5 mm.

[0053] In a first embodiment, each indicative transverse cutout has a minimum width strictly greater than 1.5 mm over the entire curvilinear length of said indicative transverse cutout and preferably has a minimum width less than or equal to 5.0 mm, preferably 3.5 mm and more preferably 2.5 mm over the entire curvilinear length of said indicative transverse cutout. Thus, the remaining depth can be measured over the entirety of the indicative transverse cutout. It is then unnecessary to look for a particular portion along the indicative transverse cutout.

[0054] In a second embodiment, each indicative transverse cutout comprises: - a so-called indicative portion, having a minimum width strictly greater than 1.5 mm, preferably less than or equal to 5.0 mm, preferably 3.5 mm and more preferably 2.5 mm, and - a so-called common portion, having a maximum width less than or equal to 1.5 mm, preferably less than or equal to 1.3 mm and more preferably 1.0 mm.

[0055] This minimizes the impact of the indicative transverse cut(s) on the performance for which it is necessary to have relatively fine transverse cuts.

[0056] Advantageously, the indicative portion is arranged axially outside the common portion. This makes it easier to measure the depth of the indicative portion.

[0057] In advantageous and optional embodiments, each common transverse cutout has a maximum width less than or equal to 1.3 mm, preferably 1.0 mm.

[0058] In advantageous and optional embodiments, the tread having a reference width LBDR as defined in the design guide of the ETRTO 2023 standard, the indicative portion of each indicative transverse cutout extends axially at least partly outside a portion of the tread of axial width 0.75 x LBDR and centered on the median plane of the tire. The reference width of the tread LBDR is defined, in the design guide of the ETRTO 2023 standard, by the formula LBDR = (1.075 - 0.005 x AR ) x S A 1.001 with AR the nominal aspect ratio and S the theoretical flange thickness on the measuring rim. This makes it easier to measure the depth of the indicative portion.

[0059] In a preferred but optional embodiment, the tire has an imposed outer side when the tire is mounted on the vehicle, the indicative transverse cutout(s) is or are provided in the axially lateral portion arranged closest to the outer side. Indeed, this makes it possible to make the indicative transverse cutout(s) easily accessible once the tire is mounted on a vehicle.

[0060] By imposed inner and outer sides when the tire is mounted on the vehicle, we mean that the tire is designed so that one of its sides is arranged on the inner side and the other of its sides is arranged on the outer side. This orientation imposed by the tire manufacturer ensures that the tire has the expected performance. Indeed, mounting a tire with an orientation different from that imposed by the manufacturer can lead to suboptimal behavior of the vehicle. By outer side, we mean the side of the tire entirely visible from the outside of the vehicle when the tire is mounted on the vehicle. By inner side, we mean the side of the tire facing the wheel arch of the vehicle on which it is mounted. Generally, the tire has a marking indicating the inner side and the outer side.

[0061] Advantageously and optionally, the tread being intended to come into contact with the ground when the tire is rolling via a rolling surface, the axially lateral portion extends axially from an axial edge of the rolling surface to an axially outer edge of the axially outer main circumferential cutout.

[0062] In a preferred but optional embodiment, the tread being intended to come into contact with the ground when the tire is rolling via a rolling surface, the indicative portion of each indicative transverse cutout extends axially at least in part between an axial edge of the rolling surface arranged on the same side of the median plane as the axially lateral portion and an axially outer edge of the axially outer main circumferential cutout arranged on the same side of the median plane as the axially lateral portion. Each indicative transverse cutout therefore extends at least in part in a portion of the tire intended to come into contact with the ground when the tire is rolling.

[0063] Conventionally, the tread surface is axially delimited by first and second axial edges which coincide respectively with the first and second axial edges of the tread. The axial width of the tread surface and the tread is considered equal to the reference width LBDR as described above.

[0064] In an advantageous and optional embodiment, each transverse cutout, whether common or indicative, extends, in the axially lateral portion in which it is formed, over an axial length at least equal to 50%, preferably 75% of the axial width of the axially lateral portion in which it is formed.

[0065] In an advantageous and optional embodiment, the indicative portion of each indicative transverse cutout extends, in the axially lateral portion in which it is formed, over an axial length at least equal to 30%, preferably 50% of the axial width of the axially lateral portion in which it is formed. A sufficiently large axial length makes it possible, on the one hand, to easily find the indicative portion and, on the other hand, to facilitate the passage of the measuring tool, in particular when it is a depth measuring gauge.

[0066] The axial width of the axially lateral portion is the distance in the axial direction from an axial edge of the rolling surface arranged on the same side of the median plane as the axially lateral portion to an axially outer edge of the axially outer main circumferential cutout arranged on the same side of the median plane as the axially lateral portion. The axial length of the indicative portion is measured in the axially lateral portion.

[0067] In an embodiment making it possible to simplify the design of the tire and not to differentiate the two parts of the tire located on either side of the median plane with regard to the indicative transverse cutout(s), the main circumferential cutouts comprise first and second axially outer main circumferential cutouts arranged axially on either side of the median plane of the tire, the first and second axially outer main circumferential cutouts being the axially outermost main circumferential cutouts of the tread, the tread comprises: - a first axially lateral portion arranged axially outside the first axially outer main circumferential cutout, - a second axially lateral portion arranged axially outside the second axially outer main circumferential cutout, the tread comprises first and second total numbers respectively of first and second transverse cutouts provided respectively in each first and second axially lateral portion, at least one and at most 30% of the first total number of first transverse cutouts is one or are first transverse cutout(s) called indicative, having, on a so-called indicative portion, a minimum width strictly greater than 1.5 mm and the remainder of the first total number of first transverse cutouts are first transverse cutouts called common, having a maximum width less than or equal to 1.5 mm,the linear density DI1 of the first indicative transverse cut(s) being defined by the ratio of the total number of first indicative transverse cut(s) formed at least partly in the first axially lateral portion to the circumference of the tire measured on the median plane and inflated to 2.5 bars, DI1 satisfies DI1 < 0.15 cm-1, and at least one and at most 30% of the second total number of second transverse cut(s) is one or are second transverse cut(s) called indicative, having, on a so-called indicative portion, a minimum width strictly greater than 1.5 mm and the remainder of the second total number of second transverse cut(s) are second transverse cut(s) called common, having a maximum width less than or equal to 1.5 mm,the linear density DI2 of the second indicative transverse cut(s) being defined by the ratio of the total number of second indicative transverse cut(s) made at least partly in the second axially lateral portion to the circumference of the tire measured on the median plane and inflated to 2.5 bars, DI2 satisfies DI2 < 0.15 cm- 1.,

[0068] In preferred and advantageous embodiments, at least two, preferably at least six of the first total number of first transverse cutouts are first indicative transverse cutouts and at least two, preferably at least six of the second total number of second transverse cutouts are second indicative transverse cutouts.

[0069] In preferred and advantageous embodiments, at least one and at most 20%, preferably at most 15% and more preferably at most 10% of the first total number of first transverse cutouts is one or are first transverse cutout(s) referred to as indicative, having, on a so-called indicative portion, a minimum width strictly greater than 1.5 mm, and at least one and at most 20%, preferably at most 15% and more preferably at most 10% of the second total number of second transverse cutouts is one or are second transverse cutout(s) referred to as indicative, having, on a so-called indicative portion, a minimum width strictly greater than 1.5 mm.

[0070] In advantageous and optional embodiments, DI1 < 0.13 cm-1 and DI2 < 0.13 cm-1, preferably DI1 < 0.10 cm-1 and DI2 < 0.10 cm-1, more preferably DI1 < 0.08 cm-1 and DI2 < 0.08 cm-1 and even more preferably DI1 < 0.05 cm-1 and DI2 < 0.05 cm-1.

[0071] In advantageous and optional embodiments, DI1 > 0.01 cm-1 and DI2 > 0.01 cm-1, preferably DI1 > 0.02 cm-1 and DI2 > 0.02 cm-1.

[0072] In advantageous and optional embodiments, the linear density DC1 of the common transverse cutouts being defined by the ratio of the total number of first common transverse cutouts formed at least in part in the first axially lateral portion to the circumference of the tire measured on the median plane and inflated to 2.5 bars, DC1 satisfies DC1 > 0.20 cm-1, preferably DC1 > 0.25 cm-1 and more preferably DC1 > 0.30 cm-1, and the linear density DC2 of the second common transverse cutouts being defined by the ratio of the total number of second common transverse cutouts formed at least in part in the second axially lateral portion to the circumference of the tire measured on the median plane and inflated to 2.5 bars, DC2 satisfies DC2 > 0.20 cm-1, preferably DC2 > 0.25 cm-1 and more preferably DC2 > 0.30 cm-1.

[0073] In advantageous and optional embodiments, DC1 < 1.40 cm-1 and DC2 < 1.40 cm-1.

[0074] In advantageous and optional embodiments applicable to so-called summer tires, DC1 < 0.60 cm-1 and DC2 < 0.60 cm-1, preferably DC1 < 0.50 cm-1 and DC2 < 0.50 cm-1 and more preferably DC1 < 0.40 cm-1 and DC2 < 0.40 cm-1.

[0075] In advantageous and optional embodiments applicable to so-called 4-season or all-season tires, DC1 satisfies 0.60 cm-1 < DC1 < 1.00 cm-1 and 0.60 cm-1 < DC2 < 1.00 cm-1, preferably 0.70 cm-1 < DC1 < 0.90 cm-1 and 0.70 cm-1 < DC2 < 0.90 cm-1.

[0076] In advantageous and optional embodiments applicable to so-called winter tires, DC1 satisfies 1.00 cm-1 < DC1 < 1.40 cm-1 and 1.00 cm-1 < DC2 < 1.40 cm-1, preferably 1.10 cm-1 < DC1 < 1.30 cm-1 and 1.10 cm-1 < DC2 < 1.30 cm-1.

[0077] Advantageously and optionally, the tread being intended to come into contact with the ground when the tire is rolling via a rolling surface, the first axially lateral portion extends axially from a first axial edge of the rolling surface to an axially outer edge of the first axially outer main circumferential cutout, the second axially lateral portion extends axially from a second axial edge of the rolling surface to an axially outer edge of the second axially outer main circumferential cutout.

[0078] In a preferred but optional embodiment, the tread being intended to come into contact with the ground during rolling of the tire via a rolling surface, the indicative portion of each first indicative transverse cutout extends axially at least in part between a first axial edge of the rolling surface arranged on the same side of the median plane as the first axially lateral portion and an axially outer edge of the first axially outer main circumferential cutout, the indicative portion of each second indicative transverse cutout extends axially at least in part between a second axial edge of the rolling surface arranged on the same side of the median plane as the second axially lateral portion and an axially outer edge of the second axially outer main circumferential cutout.

[0079] Each indicative portion therefore extends at least partly into a portion of the tire intended to come into contact with the ground when the tire is rolling.

[0080] In an advantageous and optional embodiment, each first transverse cutout, whether common or indicative, extends, in the first axially lateral portion, over an axial length at least equal to 50%, preferably 75% of the axial width of the first axially lateral portion and each second transverse cutout, whether common or indicative, extends, in the second axially lateral portion, over an axial length at least equal to 50%, preferably at 75% of the axial width of the second axially lateral portion.

[0081] The axial length of each first and second transverse cutout is measured respectively in each first and second axially lateral portion.

[0082] In an advantageous and optional embodiment, the indicative portion of each first indicative transverse cutout extends, in the first axially lateral portion, over an axial length at least equal to 30%, preferably 50% of the axial width of the first axially lateral portion in which it is formed and the indicative portion of each second indicative transverse cutout extends, in the second axially lateral portion, over an axial length at least equal to 30%, preferably 50% of the axial width of the second axially lateral portion in which it is formed.

[0083] The axial length of the indicative portion of each first and second indicative transverse cutout is measured respectively in each first and second axially lateral portion.

[0084] In advantageous and optional embodiments, the tire comprising at least one wear indicator, the or at least one of the indicative transverse cut(s) is substantially axially aligned with the wear indicator. Thus, the person wishing to determine the depth on at least one of the first and second axially lateral portions can quickly locate a transverse cut likely to be an indicative transverse cut by means of the wear indicator, the visibility of which in the main circumferential cut is high.

[0085] By substantially axially aligned is meant the indicative transverse cut and the wear indicator are included in a circumferential portion located circumferentially on either side of the indicative transverse cut and centered on the indicative transverse cut and having a circumferential length equal to 5% of the circumference of the tire. The circumference of the tire is measured in the median plane of the unmounted and uninflated tire.

[0086] Preferably and optionally, the tire comprising several wear indicators distributed circumferentially on the tread, each first and second indicative transverse cutout is substantially axially aligned with at least one of the wear indicators.

[0087] In the preceding embodiments, the or each wear indicator is preferably positioned in one of the main circumferential cutouts.

[0088] Advantageously and optionally, the ratio of the minimum width to the maximum width is greater than or equal to 1.5, preferably 2.0, more preferably to 3.0 and even more preferably to 4.0. This improves the visibility of the indicative portion compared to the common transverse cutouts.

[0089] Conventionally, the tire comprises a crown, two sidewalls, two beads, each sidewall connecting each bead to the crown. Also conventionally, the crown comprises the tread and a crown reinforcement arranged radially inside the tread. The tire also comprises a carcass reinforcement anchored in each bead and extending radially in each sidewall and axially in the crown radially inside the crown reinforcement.

[0090] Conventionally, the crown reinforcement comprises at least one crown layer comprising reinforcing elements. These reinforcing elements are preferably textile or metal wire elements.

[0091] In embodiments allowing the performance of so-called radial tires to be obtained, for example as defined by the ETRTO, the carcass reinforcement comprises at least one carcass layer, the or each carcass layer comprising carcass wire reinforcement elements, each carcass wire reinforcement element extending substantially in a main direction forming with the circumferential direction of the tire, an angle, in absolute value, ranging from 80° to 90°. Alternatively, it will be possible to have a variable angle ranging from 80° to 90° in at least one part of the sidewall and strictly less than 80° in at least one part of the crown.

[0092] The invention will be better understood on reading the description which follows, 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, and Figures 2, 3 and 4 are views similar to that of Figure 1 of tires according to respectively second, third and fourth embodiments of the invention.

[0093] In the figures relating to the tire, a reference X, Y, Z is shown corresponding to the usual axial (Y), radial (Z) and circumferential (X) directions of a tire.

[0094] Figure 1 shows a tire according to the invention and designated by the general reference 10. The tire 10 has a substantially toric shape around an axis of revolution substantially parallel to the axial direction Y. The tire 10 is intended for a passenger vehicle and has dimensions 255 / 40 R20. Tire 10 is a summer tire. The tire has an outer side EXT and an inner side INT imposed when tire 10 is mounted on the vehicle. In the various figures, tire 10 is shown in new condition, i.e. not yet driven.

[0095] The tire 10 comprises a tread 14 intended to come into contact with a ground when rolling. The tire 10 further comprises a conventional structure, such as for example described in applications WO2021250331, WO2022074341 or WO2022069819.

[0096] The tread 14 comprises a rolling surface 16 through which the tread 14 comes into contact with the ground. The rolling surface 16 is intended to come into contact with the ground when the tire 10 rolls on the ground. The rolling surface 16 is delimited axially by first and second axial edges 18, 20 defining the width LBDR of the tread 14 and of the rolling surface 16. This width LBDR is considered to be equal to the reference width LBDR as defined in the design guide of the ETRTO 2023 standard, here equal to 229 mm.

[0097] 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 on either side axially of the axially central portion PO relative to the median plane M of the tire 10. The first axially lateral portion P1 is therefore the axially lateral portion closest to the outer side EXT and the second axially lateral portion P2 is therefore the axially lateral portion closest to the inner side INT.

[0098] The tread 14 comprises N>1 main circumferential cutouts, here N main circumferential grooves, comprising first, second, third and fourth main circumferential cutouts respectively designated by the references 22, 24, 26, 28. The first and second main circumferential cutouts 22, 24 are arranged axially on either side of the median plane M of the tire 10 and are the axially outermost main circumferential cutouts of the tread 14.

[0099] The first axially lateral portion P1 and the second axially lateral portion P2 are arranged respectively axially outside the first axially outer main circumferential cutout 22 and the second axially outer main circumferential cutout 24. The first axially lateral portion P1 extends axially from the first axial edge 18 of the rolling surface 16 arranged on the same side of the median plane M as the first axially lateral portion lateral portion P1 to the axially outer edge 19 of the first main circumferential cutout 22 arranged on the same side of the median plane M as the first axially lateral portion P1 and has an axial width L1. The second axially lateral portion P2 extends axially from the second axial edge 20 of the rolling surface 16 arranged on the same side of the median plane M as the second axially lateral portion P2 to the axially outer edge 21 of the second main circumferential cutout 24 arranged on the same side of the median plane M as the second axially lateral portion P2 and has an axial width L2.

[0100] Each main circumferential cutout 22 to 28 has a depth Hr ranging from 4.0 mm to the tread height Hs, preferably ranging from 5.0 mm to the tread height Hs and more preferably ranging from 5.5 mm to the tread height Hs. Each depth Hr is greater than or equal to 50%, preferably 75% and more preferably 90% of the tread height Hs. Here, Hs=6.5 mm, Hr=6.3 mm for each first and second axially outer main circumferential cutout 22, 24 and Hr=6.5 mm for each main circumferential cutout 26, 28 of the axially central portion PO.

[0101] Each main circumferential cutout 22 to 28 respectively has an axial width greater than or equal to 3.0 mm, preferably greater than or equal to 5.0 mm and more preferably ranging from 5.0 mm to 20.0 mm.

[0102] The axially central portion PO comprises central ribs and here first, second and third central ribs respectively designated by the references 32, 34, 36. Each central rib 32, 34, 36 is arranged axially between two of the adjacent main circumferential cutouts 22 to 28. Each central rib 32, 34, 36 comprises transverse cutouts 38, 40, 42.

[0103] Each first and second axially lateral portion P1, P2 respectively comprises a first and a second lateral rib respectively designated by the reference 44, 46.

[0104] The tread 14 comprises a first total number of N1 first transverse cutouts 48 formed in the first axially lateral portion P1 and a second total number of N2 second transverse cutouts 50 formed in the second axially lateral portion P2. Here N1=N2=82.

[0105] The first transverse cutouts 48 formed in the first axially lateral portion P1 comprise 76 first common transverse cutouts 481 and 6 first indicative transverse cutouts 482. Thus, at least one, preferably at least two and more preferably at least six, and at most 30%, preferably at most 20%, more preferably at most 15% and very preferably at plus 10% of the first total number N1 of first transverse cutouts are indicative first transverse cutouts 482.

[0106] The tire 10 has a circumference C measured on the median plane M and on the tire inflated to 2.5 bars here equal to 224 cm. Thus, the linear density DC1 of the first common transverse cutouts 481 being defined by the ratio of the total number of first common transverse cutouts 481 formed at least in part in the first axially lateral portion P1 on the circumference C, DC1 satisfies on the one hand, DC1 < 0.60 cm-1, preferably DC1 < 0.50 cm-1 and more preferably DC1 < 0.40 cm-1 and on the other hand DC1 > 0.20 cm-1, preferably DC1 > 0.25 cm-1 and more preferably DC1 > 0.30 cm-1. Here, DC1 = 0.34 cm-1.Furthermore, the linear density DI1 of the first indicative transverse cutouts 482 being defined by the ratio of the total number of first indicative transverse cutouts 482 formed at least in part in the first axially lateral portion P1 on the circumference C, DI1 satisfies on the one hand DI1 < 0.15 cm-1, preferably DI1 < 0.13 cm-1, more preferably DI1 < 0.10 cm-1, even more preferably DI1 < 0.08 cm-1 and very preferably DI1 < 0.05 cm-1 and on the other hand DI1 > 0.01 cm-1, preferably DI1 > 0.02 cm-1. Here, DI1 = 0.03 cm-1.

[0107] Each first transverse cutout 48 extends, in the first axially lateral portion P1, over an axial length at least equal to 50%, preferably 75% and here equal to 100% of the axial width L1 of the first axially lateral portion P1. Each second transverse cutout 50 extends, in the second axially lateral portion P2, over an axial length at least equal to 50%, preferably 75% and here equal to 100% of the axial width L2 of the second axially lateral portion.

[0108] The second transverse cutouts 50 formed in the second axially lateral portion P2 comprise 82 second common transverse cutouts 501 and no second indicative transverse cutout 502.

[0109] Each first and second common transverse cutout 481, 501 has a maximum width less than or equal to 1.5 mm, preferably 1.3 mm and more preferably 1.0 mm and here equal to 0.4 mm. Each first and second common transverse cutout 481, 501 has a depth greater than or equal to 50%, preferably 75% of the tread height Hs and here equal to 5.2 mm.

[0110] Each first indicative transverse cutout 482 comprises an indicative portion 4821 having a minimum width strictly greater than 1.5 mm and less than or equal to 5.0 mm, preferably 3.5 mm and more preferably 2.5 mm and here equal to 2.0 mm.

[0111] The ratio of the minimum width to the maximum width is greater than or equal to 1.5, preferably 2.0, more preferably 3.0 and even more preferably 4.0 and here equal to 5.0.

[0112] In the embodiment of Figure 1, the indicative portion 4821 extends, in the first axially lateral portion P1, over an axial length La1 at least equal to 30%, preferably 50% of the axial width L1 of the first axially lateral portion P1 in which it is formed and here over the entire axial width L1 of the first axially lateral portion P1. The indicative portion 4821 extends axially at least in part outside the part of the tread 14 of axial width 0.75 x LBDR (here equal to 172 mm) and centered on the median plane M. The indicative portion 4821 extends axially at least in part between the first axial edge 18 and the axially outer edge 19 of the first axially outer main circumferential cutout 22.

[0113] Each indicative portion 4821 has a depth greater than or equal to 50%, preferably 75% of the sculpture height Hs and here equal to 5.2 mm.

[0114] The tire 10 comprises wear indicators 60 distributed circumferentially on the tread 14. The wear indicators 60 are positioned in several of the main circumferential cutouts 22 to 28, here in each main circumferential cutout 22 to 28. The tire 10 comprises 6 wear indicators 60 in each main circumferential cutout 22 to 28, i.e. a total of 24 wear indicators.

[0115] Each first indicative transverse cutout 482 is substantially axially aligned with at least one of the wear indicators 60. Indeed, the wear indicators 60 are included in a circumferential portion C1 situated circumferentially on either side of the first indicative transverse cutout 482 and centered on the indicative transverse cutout 482. The center of the first indicative transverse cutout 482 is an axial straight line D passing through a point of the first indicative transverse cutout 482 circumferentially equidistant from the two ends of the first indicative transverse cutout 482. The circumferential portion C1 has a circumferential length C0 equal to 5% of the circumference of the tire, i.e. 2240 x 5 / 100 mm = 112 mm.

[0116] Figures 2, 3 and 4 show tires 10 according to second, third and fourth embodiments. Elements similar to the first embodiment are designated by identical references.

[0117] With reference to Figure 2 and unlike the tire according to the first embodiment, each first indicative transverse cutout 482 comprises: - an indicative portion 4821 having a minimum width strictly greater than 1.5 mm and less than or equal to 5.0 mm, preferably 3.5 mm and more preferably 2.5 mm and here equal to 2.0 mm - a common portion 4822 having a maximum width less than or equal to 1.5 mm and preferably less than or equal to 1.3 mm and more preferably 1.0 mm and here equal to 0.4 mm.

[0118] Each indicative portion 4821 is arranged axially outside each common portion 4822.

[0119] With reference to Figure 3 and unlike the tire according to the second embodiment, at least one, preferably at least two and more preferably at least six and at most 30%, preferably at most 20%, more preferably at most 15% and very preferably at most 10% of the second total number N2 of second transverse cutouts 50 are indicative second transverse cutouts 502. The second transverse cutouts 50 comprise 76 common second transverse cutouts 501 and six indicative second transverse cutouts 502.

[0120] In a similar manner to the first indicative transverse cutouts 482, the tire 10 having a circumference C measured on the median plane M and on the tire inflated to 2.5 bars here equal to 224 cm, the linear density DC2 of the second common transverse cutouts 501 being defined by the ratio of the total number of second common transverse cutouts 501 formed at least in part in the second axially lateral portion P2 on the circumference C, DC2 satisfies on the one hand DC2 < 0.60 cm-1, preferably DC2 < 0.50 cm-1 and more preferably DC2 < 0.40 cm-1 and on the other hand DC2 > 0.20 cm-1, preferably DC2 > 0.25 cm-1 and more preferably DC2 > 0.30 cm-1. Here, DC2 = 0.34 cm-1.

[0121] Furthermore, the linear density DI2 of the second indicative transverse cutouts 502 being defined by the ratio of the total number of second indicative transverse cutouts 502 formed at least in part in the second axially lateral portion P2 on the circumference C, DI2 satisfies on the one hand DI2 < 0.15 cm-1, preferably DI2 < 0.13 cm-1, more preferably DI2 < 0.10 cm-1, even more preferably DI2 < 0.08 cm-1 and very preferably DI2 < 0.05 cm-1 and on the other hand DI2 > 0.01 cm-1, preferably DI2 > 0.02 cm-1. Here, DI2 = 0.03 cm-1.

[0122] In a similar manner to the first indicative transverse cutouts 482, each second indicative transverse cutout 502 comprises an indicative portion 5021 having a minimum width strictly greater than 1.5 mm and less than or equal to 5.0 mm, preferably 3.5 mm and more preferably 2.5 mm and here equal to 2.0 mm.

[0123] In the embodiment of Figure 3, the indicative portion 5021 of each second indicative transverse cutout 502 extends, in the second axially lateral portion P2, over an axial length La2 at least equal to 30%, preferably 50% of the axial width L2 of the second axially lateral portion P2 in which it is formed.

[0124] The indicative portion 5021 extends axially at least partly outside the portion of the tread 14 of axial width 0.75 x LBDR and centered on the median plane M. The indicative portion 5021 extends axially at least partly between the first axial edge 20 and the axially outer edge 21 of the second axially outer main circumferential cutout 24.

[0125] As in the second embodiment, each second indicative transverse cutout 502 comprises: - the indicative portion 5021, and - a common portion 5022 having a maximum width less than or equal to 1.5 mm and preferably less than or equal to 1.3 mm and more preferably 1.0 mm and here equal to 0.4 mm.

[0126] Each first and second indicative transverse cutout 482, 502 is substantially axially aligned with at least one of the wear indicators 60. Indeed, in addition to being included in the circumferential portion C1, the wear indicators 60 are included in a circumferential portion CT situated circumferentially on either side of the second indicative transverse cutout 502 and centered on the second indicative transverse cutout 502. The center of the second indicative transverse cutout 502 is an axial straight line D' passing through a point of the second indicative transverse cutout 502 circumferentially equidistant from the two ends of the second indicative transverse cutout 502. The circumferential portion CT has the circumferential length C0 equal to 5% of the circumference of the tire.

[0127] With reference to Figure 4, unlike the third embodiment, the tread 14 comprises, in addition to the wear indicators 60 positioned in the main circumferential cutouts 22, 24, 26, 28, wear indicators 62 positioned in the extension of the indicative portion 4821, 5021 of each first and second indicative transverse cutout 482, 502. These wear indicators 62 comprise wells of different depths and as described for example in WO2018162822. The wear indicators 62 are not cutouts insofar as, contrary to the definition of a cutout, the width and the curvilinear length of the wear indicators are substantially equal.

[0128] It will also be possible to envisage a fourth embodiment relating to a 4-season or all-season tire in which, unlike the previous embodiments, DC1 and / or DC2 satisfy 0.60 cm-1 < DC1 < 1.00 cm-1 and / or 0.60 cm-1 < DC2 < 1.00 cm-1, preferably 0.70 cm-1 < DC1 < 0.90 cm-1 and / or 0.70 cm-1 < DC2 < 0.90 cm-1 and for example DC1=DC2=0.79 cm-1. As for the densities DI1, DI2, they satisfy the same criteria as in the previous embodiments.

[0129] A fifth embodiment relating to a winter tire may also be considered in which DC1 satisfies 1.00 cm-1 < DC1 < 1.40 cm-1 and / or 1.00 cm-1 < DC2 < 1.40 cm-1, preferably 1.10 cm-1 < DC1 < 1.30 cm-1 and / or 1.10 cm-1 < DC2 < 1.30 cm-1 and for example DC1=DC2=1.13 cm-1. As for the densities DI1, DI2, they satisfy the same criteria as in the previous embodiments.

[0130] The invention is not limited to the embodiments described above.

[0131] In some variants, each transverse cutout, whether common or adjacent, opens into the outer main circumferential cutout adjacent to it. In other variants, each transverse cutout, whether common or adjacent, is blind and therefore does not open into the outer main circumferential cutout adjacent to it.

Claims

CLAIMS 1. Tire (10) comprising a tread (14) comprising: - main circumferential cutouts (22, 24, 26, 28) having a depth greater than or equal to 50% of the tread height comprising at least one axially outer main circumferential cutout (22, 24), the axially outer main circumferential cutout (22, 24) being, on one side of a median plane of the tire, the axially outermost main circumferential cutout of the tread (14), - at least one axially lateral portion (P1, P2) arranged axially outside the axially outer main circumferential cutout (22, 24), the tread comprising a total number of transverse cutouts (48, 50) formed in said axially lateral portion (P1, P2), characterized in that at least one and at most 30% of the total number of transverse cutouts (48, 50) is one or are transverse cutout(s) called indicative (482, 502), having, on a so-called indicative portion (4821, 5021), a minimum width strictly greater than 1.5 mm and the remainder of the total number of transverse cutouts (48, 50) are transverse cutouts called common (481, 501), having a maximum width less than or equal to 1.5 mm and in that the density linear DI1 of the indicative transverse cut(s) (482, 502) being defined by the ratio of the total number of indicative transverse cut(s) (482,502) provided at least in part in the axially lateral portion (P1, P2) on the circumference (C) of the tire measured on the median plane (M) and inflated to 2.5 bars, DI1 satisfies DI1 < 0.15 cm-1., 2. Tire (10) according to the preceding claim, in which at most 20%, preferably at most 15% and more preferably at most 10% of the total number of transverse cutouts (48, 50) is one or are indicative transverse cutout(s) (482, 502).

3. Tire (10) according to any one of the preceding claims, in which DI1 < 0.13 cm-1, preferably DI1 < 0.10 cm-1, more preferably DI1 < 0.08 cm-1 and even more preferably DI1 < 0.05 cm-1.

4. Tire (10) according to any one of the preceding claims, in which the linear density DC1 of the common transverse cutouts (481, 501) is defined by the ratio of the total number of common transverse cutouts (481, 501) formed at least in part in the axially lateral portion (P1, P2) to the circumference (C) of the tire measured on the median plane (M) and inflated to 2.5 bars, DC1 satisfies DC1 > 0.20 cm-1, preferably DC1 > 0.25 cm-1 and more preferably DC1 > 0.30 cm-1.

5. Tire (10) according to the preceding claim, in which DC1 < 1.40 cm-1.

6. Tire (10) according to claim 4 or 5, in which DC1 satisfies DC1 < 0.60 cm-1, preferably DC1 < 0.50 cm-1 and more preferably DC1 < 0.40 cm-1.

7. A tire (10) according to claim 4 or 5, wherein DC1 satisfies 0.60 cm-1 < DC1 < 1.00 cm-1, preferably 0.70 cm-1 < DC1 < 0.90 cm-1.

8. A tire (10) according to claim 4 or 5, wherein DC1 satisfies 1.00 cm-1 < DC1 < 1.40 cm-1, preferably 1.10 cm-1 < DC1 < 1.30 cm-1.

9. A tire (10) according to any one of the preceding claims, wherein the indicative portion (4821, 5021) of each indicative transverse cutout (482, 502) has a minimum width less than or equal to 5.0 mm, preferably 3.5 mm and more preferably 2.5 mm.

10. A tire (10) according to any one of the preceding claims, wherein the indicative portion (4821, 5021) of each indicative transverse cutout (482, 502) extends over an axial length at least equal to 30%, preferably 50% of the axial width of the axially lateral portion (P1, P2) in which it is formed.

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