Heavy-duty vehicle tire with improved tread strength

Abstract

The present invention aims to improve, for a tire for a heavy goods vehicle, the robustness of its tread (1) comprising at least two complex cutouts (5) each having an alternation of external cavities (6) and strictions (7).According to the invention, for any incision (9), joining two external cavities (6) belonging respectively to two adjacent complex cutouts (5), the distance (D) between each point of intersection (I1, I2) of the incision (9) with each external cavity (6) and a bisector plane (P) of the external cavity (6) is at least equal to 25% and at most equal to 50% of the length (Le) of the external cavity (6), the first point of intersection (I1) with an external cavity (6) of the first complex cutout (5) is positioned in the vicinity of the leading end (E1) of said external cavity (6), and the second point of intersection (I2) with the external cavity (6) of the second complex cutout (5) is positioned in the vicinity of the trailing end (E2) of said external cavity (6). Abstract figure: Fig.2.

Description

Title of the invention: Heavy goods vehicle tire with a tread with improved robustness

[0001] The present invention relates to a tire for a heavy goods vehicle, intended to run on tarmacked roads, and more particularly concerns its tread.

[0002] A tread, located at the periphery of the tire and intended to be worn when it comes into contact with a ground via a rolling surface, is made of at least one rubber-based material. It generally comprises a sculpture which is a combination of cutouts, or hollows, and raised elements, intended in particular to ensure satisfactory grip performance, more particularly on a wet road surface.

[0003] As is known, the driving conditions of a vehicle in wet weather, and more particularly those of a heavy goods vehicle, require rapid evacuation of the water present in the contact surface between the tread of the tire and the road surface. This evacuation ensures direct contact of the material constituting the tread with this road surface via the rolling surface. The water which is not pushed towards the front or the sides of the tire flows away or is partly captured in the cutouts formed in the tread.

[0004] Water evacuation is ensured by the cutouts which form a fluid flow network which must preferably be long-lasting, that is to say effective throughout the entire period of use of the tire between its new condition and its maximum state of wear. The maximum state of wear, set by the regulations in force, is the state from which the tire must be removed from the vehicle for safety reasons.

[0005] Heavy goods vehicle tires generally have a relatively large available void volume in the contact patch when new. Available void volume means a void volume that can be filled by water present on the road surface. The void volume opening onto the rolling surface is evaluated when the tire is subjected to recommended inflation and load conditions as defined in particular by the European standards of the “European Tyre and Rim Technical Organization” or “ETRTO” in its “Standards Manual 2022 - Commercial Vehicle Tyres”.

[0006] Among the cutouts, we distinguish incisions and grooves. The incisions have a width such that the facing material walls delimiting them come into contact at least partially with each other, when the tread passes through the contact surface, under the load and pressure conditions of the tire specified by the ETRTO: which limits the deformations of the facing material portions and therefore the wear. On the other hand, the grooves, wider than the incisions, delimit portions of material which can deform without coming into contact with each other, when the tread passes through the contact surface. These deformations of the material portions, in compression and in shear, contribute to an increase in the wear of the tread.Furthermore, in the case of the presence of grooves, an increase in deformations generates an increase in hysteretic losses of the tread, therefore in rolling resistance and, consequently, higher fuel consumption.

[0007] To limit the reduction in the volume of material of the tread resulting from the presence of grooves, so-called complex cutouts have been proposed which make it possible, compared to conventional grooves, which are entirely open over the tread surface, to increase the volume of material of the tread while respecting the hollow volume for water storage beyond a determined threshold, whatever the level of wear of the tire.

[0008] Treads comprising such complex cutouts have been described in particular in documents WO 2011039194 A1, WO 2011101495 A1, WO 2012130735 A1 and WO 2020030667 A1. A complex cutout opens discontinuously, at regular or irregular intervals, onto the new tread surface. Each complex cutout has external cavities, open onto the tread surface and separate from each other in the main direction of the complex cutout. The main direction of the complex cutout corresponds to the direction of flow of water in said cutout when rolling on water-covered ground. This complex cutout comprises, in addition to the external cavities, internal cavities formed inside the tread and generally connected to the tread surface by incisions.These internal cavities are positioned radially and completely inside the running surface in the new state, and intercalated between the external cavities. The internal cavities can be positioned at different depth levels in the thickness of the strip. In addition, the continuity of the flow of water, or more generally of fluid, in the new state, in each complex cut is ensured by the connection between the external and internal cavities respectively. The connections between the internal and external cavities thus form a continuous groove, independently of the local orientation of the internal or external cavities. On the other hand, the juxtaposition of internal and external cavities not linked to each other, and therefore . not allowing fluid flow from one to the other around the entire circumference of the tire, does not constitute a continuous groove.

[0009] For a tread with complex cutouts, the volume of all the cavities, internal and external, is reduced compared to that of grooves fully open on the new tread surface and having a depth corresponding to the maximum depth of the internal or external cavities. The presence of complex cutouts thus makes it possible to limit the reduction in rigidity of the tread in the new condition linked to the presence of the grooves.

[0010] A tread sculpture may comprise both complex cutouts, opening onto the tread surface intermittently, and conventional grooves, opening onto the tread surface over their entire length.

[0011] However, it has been found that the sole presence of complex cutouts does not make it possible to achieve the level of grip in traction and braking required on certain heavy goods vehicles and that it is advisable to combine these complex cutouts with oblique incisions, i.e. inclined relative to the main direction of the grooves, opening onto the running surface in the new condition. These oblique incisions generate, in the running surface, an additional length of edges, making it possible to achieve a good level of traction and satisfactory grip in so-called "slippery" conditions, particularly on ground covered with water.

[0012] The presence of incisions nevertheless weakens the tread, which can lead to pieces of rubber being torn off and impair grip and wear performance.

[0013] Damage to the tread generally begins with the initiation of cracks in the material, resulting either from exceeding the breaking stress or the fatigue limit of the material. In both cases, the preferred areas for crack initiation are those of stress concentration, corresponding to a local geometry characterized by small radii of curvature or angles having a small angular opening. This is particularly the case for an incision, the small thickness of which, typically at most equal to 2 mm, imposes a small radius of curvature at its base, and the connection of which to the complex cutout, to which it is connected, is most often made at an angle of inclination, relative to the main direction of said complex cutout, of small angular opening, with a view to optimization with respect to the noise generated.

[0014] Usually, the problem of crack initiation is encountered in two situations: during the manufacture of the tire, during its demolding at the end of curing, or during the use of the tire.

[0015] When demolding the tire, at the end of cooking, the sculpture elements that are difficult to demold, in particular the hidden internal cavities of the cutouts complex, exert radial traction on the tread, which can lead, in stress concentration areas, to stresses that can exceed the breaking stress of the material. The difficulty of demolding and the associated risk of tearing increase with the number and width of hidden internal cavities.

[0016] When using the tire, driving over blunt objects can also lead to exceeding the breaking stress of the material. In addition, repeated stresses in drift or torque passage can lead to exceeding the fatigue limit over time.

[0017] It is known to those skilled in the art to add, at the base of an incision, a small cavity having a radius of curvature sufficient to obtain stresses, at the base of the incision, lower than the breaking stress, thus avoiding the initiation of cracks. In return, the tread has a lower rigidity, with a risk of reduced wear performance, the demolding of the tread is more complex and the cost of producing the mold parts of the tread is higher.

[0018] Other risks have been identified by those skilled in the art, with regard to the combination of complex cutouts and incisions opening into the external cavities of said complex cutouts. In particular, the relative arrangement of the external cavities between several complex cutouts as well as that of the oblique incisions are likely to generate additional noise phenomena and / or to introduce inhomogeneous wear of the tread.

[0019] In addition to the disadvantages linked to the presence of oblique incisions opening into complex cutouts, described above, those skilled in the art have also noted that the presence of complex cutouts in the tread increases the risk of stones being captured and jammed in the external cavities of said complex cutouts, which are also likely to generate cracks in the tread.

[0020] The inventors also set themselves the objective of improving the resistance to cracking and tearing of a tread comprising a combination of complex cutouts and incisions connecting them, by limiting the generation of noise and guaranteeing a satisfactory compromise between the performances respectively in wear, grip and rolling resistance.

[0021] This objective has been achieved by a tire for a heavy goods vehicle comprising a tread, intended to come into contact with a ground via a rolling surface and comprising cutouts delimiting raised elements, - the tread having a thickness, measured perpendicular to the tread surface and being equal to the depth of the deepest cut, -the tread comprising at least two adjacent complex cutouts, each comprising, when new, an alternation of external cavities and neckings, -each external cavity having a length, measured on the rolling surface, between a leading end, intended to first come into contact with the ground, in the direction of rolling of the tire, and a trailing end, intended to last come into contact with the ground, the two ends respectively leading and trailing being positioned on a mean line of the external cavity, - the external cavity having a width, measured perpendicular to the mean line of the external cavity, the maximum value of which is at least equal to 6 mm, and having a height, measured perpendicular to the rolling surface, -each constriction, having a width, measured perpendicular to a mean line of the constriction, at most equal to the width of the external cavity and at most equal to 2 mm, and having a height, measured perpendicular to the rolling surface, -the necking being extended radially inwards by an internal cavity, having a width, measured perpendicular to a mean line of the internal cavity, and having a height, measured perpendicular to the rolling surface, -at least one incision, extending from a first point of intersection with an external cavity of a first complex cutout to a second point of intersection with the nearest external cavity of a second complex cutout adjacent to the first complex cutout, - the incision having a width, measured perpendicular to a mean line of the incision, at most equal to 2 mm, and having a height, measured perpendicular to the rolling surface, - the distance between each point of intersection of the incision with each external cavity and a bisecting plane of the external cavity, perpendicular to the mean line of the external cavity and equidistant from the leading and trailing ends of the external cavity, being at least equal to 25% and at most equal to 50% of the length of the external cavity, -the first point of intersection of the incision with an external cavity of the first complex cutout being positioned in the vicinity of the leading end of said external cavity, -and the second point of intersection of the incision with the external cavity closest to the second complex cutout being positioned in the vicinity of the trailing end of said external cavity.

[0022] The invention is essentially characterized by an optimization of the positioning of the incisions connecting the external cavities closest to each other of two adjacent complex cutouts.

[0023] According to a first essential characteristic, the distance between each point of intersection of the incision with each external cavity and a bisecting plane of the external cavity, perpendicular to the mean line of the external cavity and equidistant from the leading and trailing ends respectively of the external cavity, is at least equal to 25% and at most equal to 50% of the length of the external cavity. In other words, the incision opens into an external cavity, and not into a constriction zone extended radially inwards by an internal cavity.

[0024] During the manufacture of the tire, and, more particularly, at the end of its curing step in a mold, this positioning of the incision has the advantage of avoiding the appearance of cracks at the base of said incision, at the time of demolding of the nearest internal cavity. When rolling, this positioning of the incision promotes the ejection of potentially blocked stones, at the level of one end of the external cavity into which the incision opens, thanks to the local softening of the tread conferred by said incision.

[0025] According to the second and third essential characteristics of the invention respectively, the first point of intersection of the incision with an external cavity of the first complex cutout is positioned in the vicinity of the leading end of said external cavity, and the second point of intersection of the incision with the external cavity closest to the second complex cutout is positioned in the vicinity of the trailing end of said external cavity.

[0026] This respective positioning of the ends of the incision relative to each external cavity into which it opens makes it possible, thanks to an optimization of the phase shift between the respective external cavities of the two adjacent complex cutouts, on the one hand to limit the generation of noise by the incision, and on the other hand to limit the appearance of irregular wear at the external cavities.

[0027] Advantageously, the incision having, with respect to the direction of the bisector plane of the external cavity, an average angle of inclination, defined as the slope of the straight line passing through the two points of intersection of the incision with the external cavities, the average angle of inclination is at least equal to 10° and at most equal to 45°, preferably at least equal to 20° and at most equal to 35°. An average angle of inclination of the incision, included in this interval, contributes to a limitation of the noise generated by the incision.

[0028] Still advantageously, the incision having, with respect to the direction of the bisector plane of each external cavity, an angle of incidence at the point of intersection, defined as the slope of the straight line tangent to the incision, at the point of intersection, the angle of incidence is at most equal to the average inclination angle. This angle of incidence characterizes the positioning of the average line of the incision with respect to the edge of the external cavity, and consequently defines the angular sector of the portion of material delimited by the incision and the edge of the external cavity. Thus, the lower this angle of incidence, the less the angular sector of the portion of material forms a sharp angle, which reduces the risk of local tearing at the edge of the external cavity, near its intersection with the incision.

[0029] Also advantageously, each incision has a constant height. A constant height avoids any geometric singularity at the base of the incision, such as a detachment or a bridge, likely to be the site of a concentration of stresses which could induce local cracking at the base of the incision and, consequently, local tearing.

[0030] Advantageously, each incision has a height at least equal to the height of the necking. Thus, during wear of the tire, the incision remains visible on the tread surface until at least the appearance of the internal cavities on the tread surface, which guarantees the durability of the grip of the tread during wear of the tire.

[0031] Advantageously, each external cavity has a bottom radius at least equal to 2 mm. As seen previously, the higher the bottom radius, the higher the resistance to cracking.

[0032] Advantageously, each internal cavity has a width at least equal to 5 mm. A sufficiently wide cavity allows a flow of storage and / or evacuation of water favorable to satisfactory grip on wet ground, at an advanced level of wear corresponding to the presence of the internal cavities on the rolling surface.

[0033] Still advantageously, each internal cavity has a height at least equal to 5 mm. As previously, a sufficiently high cavity allows a flow of storage and / or evacuation of water favorable to satisfactory grip on wet ground, at an advanced level of wear corresponding to the presence of the internal cavities on the rolling surface.

[0034] Advantageously, each internal cavity has a bottom radius at least equal to 2 mm. As for an external cavity, the higher the bottom radius, the higher the resistance to cracking. A high bottom radius is easily conceivable for an internal cavity because it most often has sufficient width.

[0035] According to a preferred embodiment, all the cutouts are complex cutouts, which makes it possible to optimize the compromise between wear, grip and rolling resistance.

[0036] The characteristics of the invention are illustrated by schematic figures 1 to 6, not shown to scale: -[Fig.l]: Overall top view of a tread according to a first embodiment of the invention, intended for use on a steering axle. -[Fig.2]: Partial top view of a tread according to the first embodiment of the invention, -[Fig.3]: Circumferential sectional view of a portion of complex cutting of a tread according to the first embodiment of the invention, -[Fig.4]: Sectional view along an incision opening into a complex cutout of a tread according to the first embodiment of the invention, -[Fig.5]: Overall top view of a tread according to a second embodiment of the invention, intended for use on a drive axle, -[Fig.6]: Partial top view of a tread according to the second embodiment of the invention.

[0037] [Fig.l] is an overall top view of a tread 1 according to a first embodiment of the invention, intended for use on a steering axle of a heavy goods vehicle. The tread 1, intended to come into contact with a ground via a running surface 2, comprises cutouts 3 delimiting raised elements 4. The tread 1 has a thickness E, measured perpendicular to the running surface 2 and being equal to the depth of the deepest cutout 3, this thickness E being shown in [Fig.3]. The tread 1, shown in [Fig.l], comprises five adjacent complex cutouts 5 in pairs, each comprising, when new, an alternation of external cavities 6 and constrictions 7, and each having a mean line M extending in the circumferential direction XX' of the tire.Each constriction 7 of any complex cutout 5 is extended radially inwards by an internal cavity 8, shown in Figures 3 and 4. Each external cavity 6 of a given complex cutout 5 is connected to two external cavities 6 of any complex cutout 5 adjacent to said complex cutout 5 by two incisions 9.

[0038] The first embodiment of the invention is described in detail by Figures 2, 3 and 4. [Fig.2] is a partial top view of a tread according to the first embodiment of the invention previously described. [Fig.3] is a circumferential sectional view AA of a portion of complex cutout of a tread according to the first embodiment of the invention. [Fig.4] is a sectional view BB along an incision opening into a complex cutout of a tread according to the first embodiment of the invention. Each external cavity 6 has a length Le, measured on the rolling surface 2, between a leading end El, intended to come into contact first with a ground, in the rolling direction R of the tire, and a trailing end E2, intended to come into contact last with the ground.The two ends respectively leading and trailing (El, E2) are positioned on a mean line Me of the external cavity 6. The external cavity 6 has a width We, measured perpendicular to the mean line Me of the external cavity 6, the maximum value of which is at least equal to 6 mm, and has a height He, measured perpendicular to the rolling surface 2. Each necking 7 has a width Ws, measured perpendicular to a mean line Ms of the necking 7, at . more equal to the width We of the external cavity 6 and at most equal to 2 mm, and has a height Hs, measured perpendicular to the rolling surface 2. The necking 7 is extended radially inwards by an internal cavity 8, having a width Wc, measured perpendicular to a mean line of the internal cavity, and has a height Hc, measured perpendicular to the rolling surface 2. Any incision 9 extends from a first point of intersection II with an external cavity 6 of a first complex cutout 5 to a second point of intersection 12 with the nearest external cavity 6 of a second complex cutout 5 adjacent to the first complex cutout 5. The incision 9 has a width Wi, measured perpendicular to a mean line Mi of the incision 9, at most equal to 2 mm, and has a height Hi, measured perpendicular to the rolling surface 2.According to a first characteristic of the invention, the distance D between each point of intersection (II, 12) of the incision 9 with each external cavity 6 and a bisector plane P of the external cavity 6, perpendicular to the mean line Me of the external cavity 6 and equidistant from the leading and trailing ends respectively (El, E2) of the external cavity 6, is at least equal to 25% and at most equal to 50% of the length Le of the external cavity 6. According to a second characteristic of the invention, the first point of intersection II of the incision 9 with an external cavity 6 of the first complex cutout 5 is positioned in the vicinity of the leading end El of said external cavity 6. According to a second characteristic of the invention, the second point of intersection 12 of the incision 9 with the external cavity 6 closest to the second complex cutout 5 is positioned in the vicinity of the trailing end E2 of said external cavity 6. As described in the [Fig.2], the incision 9 has, with respect to the direction of the bisector plane P of the external cavity 6, an average inclination angle Am, defined as the slope of the straight line passing through the two points of intersection (II, 12) of the incision with the external cavities 6. Advantageously, the average inclination angle Am is at least equal to 10° and at most equal to 45°. As also described in [Fig.2], the incision 9 having, with respect to the direction of the bisector plane P of each external cavity 6, an angle of incidence (Al, A2) at the point of intersection (II, 12), defined as the slope of the straight line tangent to the incision 9, at the point of intersection (II, 12). Advantageously, the angle of incidence (Al, A2) is at most equal to the average angle of inclination Am. In the particular case shown in [Fig.2], the angles Am, Al and A2 are equal.

[0039] A second embodiment of the invention relates to a tread 1 of a tire, intended to equip a drive axle of a heavy vehicle, and is described in FIGS. 5 and 6. [Fig. 5] is an overall top view of a tread according to a second embodiment of the invention, intended for use on a drive axle of a heavy goods vehicle. [Fig. 6] is a view of partial top of a tread according to the second embodiment of the invention. The references previously described remain valid in the present case. This second embodiment of the invention differs from the first by complex cutouts each having a mean line forming a broken line and having a generally transverse orientation relative to the rolling direction of the tire.

[0040] The inventors have more particularly studied this invention for a tire for a heavy goods vehicle in the dimensions 315 / 70 R 22.5 for use on a steering axle, according to a first embodiment of the invention II, and 295 / 80 R 22.5 for use on a driving axle, according to a second embodiment of the invention 12.

[0041] Table 1 below shows the characteristics of the tested tread: [Tables 1] Characteristics II 12 Comments Thickness E of tread 1 15 mm 20.5 mm Maximum width We of external cavity 6 13.7 mm or 7.2 mm 12 mm At least equal to 6 mm Length Le of external cavity 6 39 mm 30 mm Height He of external cavity 6 15 mm 20. 5 mm Width Ws of necking 7 0.6 mm 0.4 mm At most equal to 2 mm Height Hs of necking 7 5.5 mm 11.5 mm Width Wc of internal cavity 8 8.7 mm or 5.2 mm 6.5 mm At least equal to 5 mm Height Hc of internal cavity 8 9.5 mm 9 mm At least equal to 5 mm Width Wi of incision 9 0.4 mm 0.8 mm At most equal to 2 mm Height Hi of incision 9 11 mm or 8 mm 18.5 mm Hi at least equal to Hs Distance D between a point of intersection (II, 12) of the incision 9 with an external cavity 6 and the bisector plane P of the external cavity 6 13.5 mm 10 mm Ratio D / Le 35% 33% Between 25% and 50% Angle of inclination Am of incision 9, relative to the bisector plane P of the external cavity 6 11° 35° Between 10° and 45° Angle of incidence (Al, A2) of incision 9, at the level of the point of intersection (II, 12), relative to the bisector plane P of the external cavity 6 11° 0° At most equal to Am .

[0042] The rolling tests, carried out on the previously described embodiments, have shown that treads, according to the invention, suitable for use on a steering axle or a driving axle of a heavy goods vehicle, present an interesting compromise of performance between wear, rolling resistance and grip on wet ground, with a significant improvement in the robustness of the complex cutouts combined with incident incisions both in manufacturing, during demolding of the tread, and in use, with facilitated ejection of stones likely to be stuck in the external cavities.

Claims

Claims

1. A tire for a heavy goods vehicle comprising a tread (1), intended to come into contact with a ground via a rolling surface (2) and comprising cutouts (3) delimiting raised elements (4), - the tread (1) having a thickness (E), measured perpendicular to the rolling surface (2) and being equal to the depth of the deepest cutout (3), -the tread (1) comprising at least two adjacent complex cutouts (5), each comprising, when new, an alternation of external cavities (6) and strictions (7), -each external cavity (6) having a length (Le), measured on the rolling surface (2), between a leading end (El), intended to first come into contact with the ground, in the rolling direction (R) of the tire, and a trailing end (E2), intended to last come into contact with the ground, the two leading and trailing ends respectively (El, E2) being positioned on a mean line (Me) of the external cavity (6), -the external cavity (6) having a width (We), measured perpendicular to the mean line (De) of the external cavity (6), the maximum value of which is at least equal to 6 mm, and having a height (He), measured perpendicular to the rolling surface (2), -each necking (7), having a width (Ws), measured perpendicular to a mean line (Ms) of the necking (7), at most equal to the width (We) of the external cavity (6) and at most equal to 2 mm, and having a height (Hs), measured perpendicular to the rolling surface (2), -the necking (7) being extended radially inwards by an internal cavity (8), having a width (Wc), measured perpendicular to a mean line of the internal cavity (8), and having a height (Hc), measured perpendicular to the rolling surface (2), -at least one incision (9), extending from a first point of intersection (II) with an external cavity (6) of a first complex cutout (5) to a second point of intersection (12) with the external cavity (6) closest to a second complex cutout (5) adjacent to the first complex cutout (5), -the incision (9) having a width (Wi), measured perpendicular to a mean line (Mi) of the incision (9), at most equal to 2 mm, and having a height (Hi), measured perpendicular to the rolling surface (2), characterized in that the distance (D) between each point of intersection (II, 12) of the incision (9) with each external cavity (6) and a bisector plane (P) of the external cavity (6), perpendicular to the mean line (Me) of the external cavity (6) and equidistant from the leading and trailing ends respectively (El, E2) of the external cavity (6), is at least equal to 25% and at most equal to 50% of the length (Le) of the external cavity (6), in that the first point of intersection (II) of the incision (9) with an external cavity (6) of the first complex cutout (5) is positioned in the vicinity of the leading end (El) of said external cavity (6),and in that the second point of intersection (12) of the incision (9) with the external cavity (6) closest to the second complex cutout (5) is positioned in the vicinity of the trailing end (E2) of said external cavity (6).,

2. A tire according to claim 1, the incision (9) having, with respect to the direction of the bisector plane (P) of the external cavity (6), an average inclination angle (Am), defined as the slope of the straight line passing through the two points of intersection (II, 12) of the incision with the external cavities (6), in which the average inclination angle (Am) is at least equal to 10° and at most equal to 45°, preferably at least equal to 20° and at most equal to 35°.

3. A tire according to claim 2, the incision (9) having, with respect to the direction of the bisector plane (P) of each external cavity (6), an angle of incidence (Al, A2) at the point of intersection (II, 12), defined as the slope of the straight line tangent to the incision (9), at the point of intersection (II, 12), in which the angle of incidence (Al, A2) is at most equal to the average angle of inclination (Am).

4. A tire according to any one of claims 1 to 3, wherein each incision (9) has a constant height (Hi).

5. A tire according to any one of claims 1 to 4, wherein each incision (9) has a height (Hi) at least equal to the height (Hs) of the necking (7).

6. A tire according to any one of claims 1 to 5, wherein each internal cavity (8) has a width (Wc) at least equal to 5 mm.

7. A tire according to any one of claims 1 to 6, in in which each internal cavity (8) has a height (Hc) at least equal to 5 mm.

8. A tire according to any one of claims 1 to 7, wherein all the cutouts (3) are complex cutouts.

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