Tires with equal cuts of different lengths

Abstract

The present invention relates to a tire including first and second cuts (402, 404) including portions joined by a flex zone (4024, 4044). The first cut (402) has a length (L1) different from the length (L2) (X) of the second cut (404). The angle formed by the direction of the first portion (4021) and the direction of the second portion (4022) of the first cut (402) is substantially equal to the angle formed by the direction of the first portion (4041) and the direction of the second portion (4042) of the second cut (404). The angle formed by the direction of the second portion (4022) and the direction of the third portion (4023) of the first cut (402) is substantially equal to the angle formed by the direction of the second portion (4042) and the direction of the third portion (4043) of the second cut (404).

Description

[Technical Field]

[0001] The present invention relates to a tire, which is understood to be a casing intended to cooperate with a support element, such as a rim, to form a cavity, which cavity can be pressurized to a pressure higher than atmospheric pressure. The tire according to the invention has a substantially toroidal structure, exhibiting rotational symmetry about the main axis of the tire. [Background technology]

[0002] From French Patent No. 3012767 a tire for passenger cars is known which comprises a tread including circumferential ribs and cuts formed in each of the circumferential ribs.

[0003] The cuts include first, second, and third cuts, and the length along the circumference of each of the first, second, and third cuts is different from the length along the circumference of each of the other first, second, and third cuts to limit whining.

[0004] To reduce noise generated by the tire, each of the first, second and third cuts opens in first and second opening zones into each of the first and second circumferential cuts that define the circumferential rib, respectively, such that the azimuth angle of a point in the first opening zone of one of the first, second and third cuts substantially coincides circumferentially with the azimuth angle of a point in the second opening zone of another of the first, second and third cuts.

[0005] Each of the first, second, and third cuts includes a first, second, and third portion, the first and second portions being directly joined to one another by a first inflection zone, the third portion being directly joined to the second portion by a second inflection zone, and the second portion being axially intermediate the first and third portions.

[0006] When the width of the cuts is relatively narrow, molding elements known as sipe blades are used to form each of the first, second, and third cuts. These molding elements have a shape that complements the cuts intended to be formed in the tire and are usually manufactured by pressing metal sheets. Therefore, to achieve the desired angles between different sections, it is necessary to use as many pressing tools as there are different angles. Therefore, the number of tools required is relatively large, which increases the cost and time required to manufacture the molding elements.

[0007] In addition to the relatively large number of tools, the complexity of these designs is also increased due to the azimuthal placement constraints mentioned above, thus requiring adjustment of the circumferential length of each cut. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] French Patent No. 3012767 [Patent Document 2] International Publication No. 2021 / 250331 [Patent Document 3] International Publication No. 2022 / 074341 [Patent Document 4] International Publication No. 2022 / 069819 Summary of the Invention [Problem to be solved by the invention]

[0009] The object of the present invention is a tire that is molded by molding elements that generate less noise and are easy to manufacture. [Means for solving the problem]

[0010] To this end, the subject of the present invention is a tire comprising a tread including at least one circumferential rib separated by first and second circumferential cuts, and cuts made in said circumferential rib opening into each of the first and second circumferential cuts, the notches include first and second notches, each of the first and second notches including a first portion, a second portion, and a third portion, the first portion and the second portion of each of the first and second notches being directly joined to one another by a first bending zone, the second portion and the third portion of each of the first and second notches being directly joined to one another by a second bending zone, and the second portion of each of the first and second notches being disposed axially intermediate the first portion and the third portion of each of the first and second notches, respectively; a mean direction of the first portion of each of the first and second cuts is not parallel to a mean direction of the second portion of each of the first and second cuts, respectively; the average direction of the third portion of each of the first and second cuts is not parallel to the average direction of the second portion of each of the first and second cuts, respectively; The length of the first cut along the circumferential direction is different from the length of the second cut along the circumferential direction, each first and second cut open into a respective first and second circumferential cut bounding the circumferential rib in a first and second open zone, and an azimuth angle of a point in the first open zone of the first cut is substantially circumferentially aligned with an azimuth angle of a point in the second open zone of the second cut; an angle formed by an average direction of the first portion of the first cut and an average direction of the second portion of the first cut is substantially equal to an angle formed by an average direction of the first portion of the second cut and an average direction of the second portion of the second cut; an angle formed by an average direction of the second portion of the first cut and an average direction of the third portion of the first cut is substantially equal to an angle formed by an average direction of the second portion of the second cut and an average direction of the third portion of the second cut; a first portion of the first cut extends along an average direction substantially parallel to an average direction in which the first portion of the second cut extends; the second portions of the first cuts extend along an average direction substantially parallel to the average direction in which the second portions of the second cuts extend; the third portion of the first cut extends along an average direction substantially parallel to the average direction in which the third portion of the second cut extends; the length of the first portion of the first incision is different from the length of the first portion of the second incision, and / or the length of the second portion of the first incision is different from the length of the second portion of the second incision, and / or the length of the third portion of the first incision is different from the length of the third portion of the second incision; It's a tire.

[0011] The present invention allows for the simplification of the manufacture of molding elements for the cuts and the reduction of noise generated by the tire. Specifically, since the angle between the first and second portions of each of the first and second cuts and the angle between the second and third portions are equal, a single press tool is sufficient to manufacture two different molding elements, in this case, with different lengths along the circumferential direction and allowing the molding of the first and second cuts. The circumferential length can be easily adjusted by lengthening or shortening one or the other of the first and second portions without modifying the angle formed by the average direction of these first and second portions. In this way, the azimuthal arrangement constraint is respected. Furthermore, the first, second, and third portions of each cut are substantially parallel to one another. Therefore, the variation in the angle formed between each portion of the two different cuts and the axial direction is limited, thereby further reducing the noise generated by the tire according to the present invention.

[0012] Unlike cuts in which the bending zone necessarily includes two portions that are axially offset relative to each other, the cuts can be, although not necessarily, centered relative to the second portion, so that each first and second bending zone is axially positioned symmetrically relative to the central portion of each cut, thereby simplifying the tooling for producing the molded element.

[0013] The expression "directly joined to each other by a bending zone" means that no other portion of the incision is axially interposed between the two portions in question. The bending zone embodies a change in curvature of the incision between the portions in question. It will also be understood that the incision is uninterrupted between the portions in question.

[0014] The bending zones include bending points located on the neutral axis of each cut that correspond to points where the neutral axis undergoes a change in bending direction as it passes from the first portion to the second portion or vice versa.

[0015] Each of the first, second and third portions can be straight or curved.

[0016] For straight sections, determining the mean direction is straightforward.

[0017] In the case of a curved section, the mean direction of the section is the direction of a straight line connecting the two ends of the section located on the neutral axis. Since the first section and the second section are directly joined to each other by the above-mentioned inflection zone, the mean direction of the first section extends along the direction of a straight line passing through one end of the first section and the inflection point corresponding to the other end of the first section. The mean direction of the second section extends along the direction of a straight line passing through one end of the second section and the inflection point corresponding to the other end of the second section. The mean direction of the third section extends along the direction of a straight line passing through one end of the third section and the inflection point corresponding to the other end of the third section.

[0018] The length of the cut along the circumferential direction is equal to the distance along the circumferential direction between two points of the cut that are most distant along the circumferential direction.

[0019] The mean direction of the first portion and the mean direction of the second portion are not collinear, so the junction between the first portion and the second portion forms an inflection point. The mean direction of the third portion and the mean direction of the second portion are not collinear, so the junction between the third portion and the second portion also forms an inflection point. Each junction can have a corner or can be rounded.

[0020] Two mean directions are substantially parallel if the angle formed by them is 5° or less, preferably 2° or less.

[0021] Similarly, one angle is substantially equal to another if the difference between the two angles is 5° or less, preferably 2° or less.

[0022] Conversely, one mean direction is not parallel to the other mean direction if the angle formed by the two mean directions is strictly greater than 5°, preferably strictly greater than 2°.

[0023] The angle formed by two mean directions is considered to be the smallest angle between these two mean directions.

[0024] The length of a segment is the length measured along the average direction in which the segment extends. Thus, for a straight segment, the length is the distance measured between the ends of the segment. For a curved segment, the length is the distance measured along a straight line joining the ends of the segment.

[0025] By "substantially aligned" is meant that the azimuthal angles are circumferentially spaced apart from one another by at most 5% of the average distance separating two notches formed in the circumferential rib.

[0026] On the tread surface, a cut has two main characteristic dimensions: width and curvature, the curvature being at least equal to twice the width. Thus, a cut is bounded by at least two main lateral faces that determine the curvature of the cut, are connected by a base, and are separated from each other by a non-zero distance called the width of the cut.

[0027] On a new tire, the width of a cut is the maximum distance between the two major sides of the cut, measured in the radial dimension that coincides with the tread surface by default if the cut is not chamfered, or in the radially outermost radial dimension of the cut that is radially inward of the chamfered surface by default if the cut is chamfered. The width is measured substantially perpendicular to the major sides. If a width other than the default width, such as a width of a specific dimension, is specified, this width is equal to the minimum distance between the two major sides of a cut of the specific dimension.

[0028] In a new tire, the maximum radial distance between the bottom of the cut and its projection above the ground when the tire is in motion is the cut depth, which is called the tread pattern height.

[0029] The cuts can be transverse or circumferential.

[0030] The lateral cuts are such that they extend along an average direction that forms an angle with the circumferential direction of the tire that is strictly greater than 30°, preferably greater than or equal to 45°, and with the axial direction of the tire that is strictly less than or equal to 60°, preferably less than 45°. The average direction is the shortest curve connecting the two ends of the cut that is parallel to the tread surface. The lateral cuts can be continuous, such that the two major sides determining their length are uninterrupted along the length of the lateral cut, i.e., not interrupted by a tread block or another cut. The lateral cuts can also be discontinuous, such that the two major sides determining their length are interrupted by one or more tread blocks and / or one or more cuts, i.e., interrupted by one or more tread blocks and / or one or more cuts.

[0031] The circumferential cuts are such that they extend along an average direction that forms an angle of not more than 30°, preferably not more than 10°, with the circumferential direction of the tire, i.e., an angle of strictly more than 60°, preferably strictly more than 80°, with the axial direction of the tire. The average direction is the shortest curved line connecting the ends of the cut, parallel to the tread surface. In the case of a continuous circumferential cut, the ends coincide with each other and are joined by a curved line that goes around the tire's circumference. The circumferential cuts can be continuous, with the two major sides determining their length uninterrupted around the tire's circumference, i.e., uninterrupted by a tread block or another cut. The circumferential cuts can also be discontinuous, with the two major sides determining their length interrupted by one or more tread blocks and / or one or more cuts around the tire's circumference, i.e., interrupted by one or more tread blocks and / or one or more cuts.

[0032] In the case of a lateral cut, the sides are called the leading face and the trailing face, which have a leading edge and a trailing edge, respectively, the leading edge being the edge that enters the contact surface before the trailing edge for a given circumferential line.

[0033] Optionally, in embodiments that improve dry braking, each lateral cut is chamfered. The chamfer of a lateral cut can be a straight chamfer or a rounded chamfer. A straight chamfer is formed by a plane inclined relative to the front or rear surface that continues to the leading or trailing edge that circumferentially bounds the lateral cut. A rounded chamfer is formed by a curved surface that tangentially joins the continuing front or rear surface. The chamfer of a lateral cut is characterized by a height equal to the radial distance and a width equal to the distance along a direction perpendicular to the front or rear surface between a common point shared by the front or rear surface where the chamfer continues and the leading or trailing edge that circumferentially bounds the lateral cut.

[0034] In some embodiments, which optionally improve dry braking and dry lateral grip, at least one of the circumferential cuts is chamfered. The chamfer of the circumferential cut can be a straight chamfer or a rounded chamfer. A straight chamfer is formed by a plane inclined relative to the inner and outer axial surfaces, continuing to the inner or outer axial edge that axially bounds the circumferential cut. A rounded chamfer is formed by a curved surface that tangentially merges with the continuing inner or outer axial surface. The chamfer of the circumferential cut is characterized by a height equal to the radial distance and a width equal to the axial distance between a common point shared by the inner or outer axial surface where the chamfer continues and the inner or outer axial edge that axially bounds the circumferential cut.

[0035] A circumferential rib is a rib bounded axially by first and second axially adjacent circumferential notches.

[0036] The tire according to the invention has a substantially toroidal shape about an axis of rotation substantially coinciding with the axis of rotation of the tire, this axis of rotation defining the three directions customarily used by those skilled in the art: axial, circumferential and radial.

[0037] The expression "axial" means a direction substantially parallel to the axis of rotation of the tire, i.e., the axis of rotation of the tire about which it rotates.

[0038] The expression "circumferential direction" means a direction substantially perpendicular to both the axial direction and the radius of the tire in the meridian plane (in other words, tangent to a circle about the axis of rotation of the tire).

[0039] The expression "radial" means directions along the radius of the tire, i.e., directions intersecting the axis of rotation of the tire and substantially perpendicular to said axis.

[0040] The expression "median plane of the tire" (denoted by M) means a plane perpendicular to the tire's axis of rotation, located axially midway between the two beads and passing through the axial center of the crown reinforcement.

[0041] The expression "equatorial circumferential plane of the tire" (denoted by E) means a plane passing through the tire's equator in a meridian section, perpendicular to the median plane and the radial direction. The tire's equator is an axis parallel to the tire's axis of rotation in a meridian section (a plane perpendicular to the circumferential direction and parallel to the radial and axial directions) 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, the distance between these two points being equal to H.

[0042] The expression "meridian plane" means a plane perpendicular to the circumferential direction that is parallel to and contains the axis of rotation of the tire.

[0043] The terms "radially inner" and "radially outer" mean closer to and further from the tire's axis of rotation, respectively. The terms "axially inner" and "axially outer" mean closer to and further from the tire's median plane, respectively.

[0044] A bead is understood to be a part of the tire intended to enable the tire to be mounted on a mounting support, such as a wheel including a rim, and each bead is therefore intended to be mounted in particular against the flange of the rim.

[0045] Any numerical range indicated by the expression "between a and b" denotes a numerical range greater than a and less than b (i.e., excluding the limits a and b), whereas a numerical range indicated by the expression "from a to b" means a numerical range from a to b (i.e., including the precise limits a and b).

[0046] In some embodiments, the first, second, and other possible cuts are formed in one and the same circumferential rib. In other embodiments, the first, second, and other possible cuts are formed in at least two different circumferential ribs.

[0047] In a preferred embodiment of the invention, the tire is for passenger cars defined in accordance with the European Tyre and Rim Technical Organisation, or "ETRTO", standard of 2021. Such tire has a cross-section in meridian section, characterized in that, for a section height H and a nominal section width S within the meaning of the European Tyre and Rim Technical Organisation, or "ETRTO", standard of 2021, the H / S ratio, expressed as a percentage, is at most equal to 90 and at least equal to 20, and the nominal section width S is at least equal to 115 mm, preferably at least equal to 175 mm, at most equal to 385 mm, preferably at most equal to 315 mm. Furthermore, the diameter at the flange D, which defines the diameter of the tire's mounting rim, is at least equal to 15 inches and at most equal to 24 inches.

[0048] In a preferred embodiment of the invention, the tire is a "summer" tire, which is understood to be a tire that is not a "four-season" tire or an "all-season" tire, or a "winter" tire.

[0049] Winter tires are identified, among other things, by the M+S marking (M+S is an abbreviation for "Mud+Snow") and / or the 3PMSF marking (3PMSF is an abbreviation for "3 Peak Mountain Snow Flake"). Four-season or all-season tires also have the M+S and / or 3PMSF marking to reflect their snow performance. Summer tires therefore do not have the M+S or 3PMSF marking.

[0050] Optionally, each incision has a width of 0.2 mm to 3.0 mm, preferably 0.4 mm to 2.0 mm, more preferably 0.4 mm to 1.0 mm.

[0051] Optionally, each cut has a depth ranging from 2.0 mm to the tread pattern height, preferably ranging from 4.0 mm to the tread pattern height, more preferably ranging from 5.0 mm to the tread pattern height.

[0052] In an embodiment, the length of the first cut along the circumferential direction is strictly shorter than the length of the second cut along the circumferential direction; the length of the first portion of the first incision is strictly greater than the length of the first portion of the second incision, and / or the length of the second portion of the first incision is strictly shorter than the length of the second portion of the second incision, and / or the length of the third portion of the first incision is strictly greater than the length of the third portion of the second incision;

[0053] Preferably, each of the first and second cuts is made up of a first, second and third portion, in other words, if each cut has two ends, one end of the first portion coincides with one of the ends of the cut, and one end of the third portion coincides with the other of the ends of the cut.

[0054] In an embodiment, the axial length of the first cut is substantially equal to the axial length of the second cut, which is particularly advantageous when the circumferential rib in which the first and second cuts are formed has a substantially constant axial length.

[0055] The length of the incision along the axial direction is equal to the distance along the axial direction between the two most distant points of the incision along the axial direction.

[0056] In an advantageous but optional variant, in order to reduce the number of pressing tools required to manufacture the molding elements of the incisions, the angle formed by the mean direction of the first portion and the mean direction of the second portion of each of the first and second incisions is substantially equal to the angle formed by the mean direction of the second portion and the mean direction of the third portion of each of the first and second incisions, or in other words, the mean direction of each third portion is substantially parallel to the mean direction of each first portion.

[0057] In another, less advantageous optional variation, the angle formed by the average direction of the first portion and the average direction of the second portion of each of the first and second cuts is different from the angle formed by the average direction of the second portion and the average direction of the third portion of each of the first and second cuts, i.e., the average direction of each of the third portions is not parallel to the average direction of each of the first portions.

[0058] In a further preferred embodiment which allows for a simplification of the design of the pressing tool, 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.

[0059] In an embodiment, the first and second cuts are circumferentially adjacent.

[0060] Optionally, to limit winning, the cuts include a third cut, the third cut including first, second and third portions, the first and second portions of the third cut being directly joined to one another by a first bending zone, the second and third portions of the third cut being directly joined to one another by a second bending zone, and the second portion of the third cut being disposed axially intermediate the first and third portions of the third cut; an average direction of the first portion of the third cuts is not parallel to an average direction of the second portion of the third cuts; an average direction of the third portion of the third cut is not parallel to an average direction of the second portion of the third cut; the third cut has a length along the circumferential direction different from the lengths of each of the first and second cuts along the circumferential direction; the third cut opens into each of the first and second circumferential cuts that respectively bound the circumferential rib in first and second open zones, and the azimuth angle of a point in the first open zone of the third cut is substantially circumferentially aligned with the azimuth angle of a point in the second open zone of one of the first and second cuts; an angle formed by an average direction of the first portion and an average direction of the second portion of the third cut is substantially equal to each angle formed by an average direction of the first portion and an average direction of the second portion of each of the first and second cuts; an angle formed by the average direction of the second portion of the third cut and the average direction of the third portion is substantially equal to an angle formed by the average direction of the second portion of each of the first and second cuts and the average direction of the third portion; the first portion of the third incision extends along an average direction substantially parallel to the average direction in which the first portion of each of the first and second incisions extends; the second portion of the third incision extends along an average direction substantially parallel to the average direction in which the second portions of each of the first and second incisions extend; the third portion of the third incision extends along an average direction substantially parallel to the average direction in which the third portions of each of the first and second incisions extend; The length of the first portion of each of the first, second and third incisions is different from the length of the first portion of each of the other incisions among the first, second and third incisions, and / or the length of the second portion of each of the first, second and third incisions is different from the length of the second portion of each of the other incisions among the first, second and third incisions, and / or the length of the third portion of each of the first, second and third incisions is different from the length of the third portion of each of the other incisions among the first, second and third incisions.

[0061] In an embodiment, the length of the first cut along the circumferential direction is strictly shorter than the length of the second cut along the circumferential direction, and the length of the second cut along the circumferential direction is strictly shorter than the length of the third cut along the circumferential direction; the length of the first portion of the first incision is strictly greater than the length of the first portion of the second incision, and the length of the first portion of the second incision is strictly greater than the length of the first portion of the third incision, and / or the length of the second portion of the first incision is strictly less than the length of the second portion of the second incision, and the length of the second portion of the second incision is strictly less than the length of the second portion of the third incision, and / or - the length of the third portion of the first incision is strictly longer than the length of the third portion of the second incision, and the length of the third portion of the second incision is strictly longer than the length of the third portion of the third incision.

[0062] The third cut preferably includes a first portion, a second portion and a third portion.

[0063] In an embodiment, the axial length of the third incision is substantially equal to the axial length of each of the first and second incisions, which is particularly advantageous when the circumferential rib in which the first, second and third incisions are formed has a substantially constant axial length.

[0064] In an advantageous but optional variant, in order to reduce the number of pressing tools required to manufacture a molding element of an incision comprising first, second and third portions, the angle formed by the average direction of the first portion of the third incision and the average direction of the second portion is substantially equal to the angle formed by the average direction of the second portion of the third incision and the average direction of the third portion.

[0065] In another, less advantageous optional variation, the angle formed by the average direction of the first portion of the third cut and the average direction of the second portion of the third cut is different from the angle formed by the average direction of the second portion of the third cut and the average direction of the third portion of the third cut.

[0066] In a further preferred embodiment which allows for a simplification of the design of the pressing tool, 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.

[0067] In an embodiment, the third notch is circumferentially adjacent to at least one of the first and second notches, and preferably each of the first, second and third notches is circumferentially adjacent to at least one other of the first, second and third notches.

[0068] Optionally, it is preferred that each of the first and second circumferential cuts has a depth of 50% or more, preferably 75% or more, more preferably 90% or more of the tread pattern height.

[0069] Optionally, each of the first and second circumferential cuts preferably has a depth in the range of 4.0 mm to the tread pattern height, preferably in the range of 5.0 mm to the tread pattern height, and more preferably in the range of 5.5 mm to the tread pattern height.

[0070] Optionally, each of the first and second circumferential cuts preferably has a width of 1.0 mm or more, preferably 4.0 mm or more, more preferably 4.0 mm to 20.0 mm.

[0071] In a preferred embodiment, each incision has an average direction that forms an angle of 45° or more with the circumferential direction of the tire. The average direction of the incision is the direction in which a straight line connecting the two ends of the incision extends.

[0072] Conventionally, a tire includes a crown, two sidewall portions, and two beads, each sidewall portion connecting a respective bead to the crown. Also conventionally, the crown includes a tread and a crown reinforcement disposed radially inward of the tread. The tire also includes a carcass reinforcement anchored to each bead, extending radially inward of the crown reinforcement in each sidewall, and extending axially in the crown.

[0073] Conventionally, the crown reinforcement comprises at least one crown layer containing reinforcing elements, preferably woven or metallic filamentary elements.

[0074] In an embodiment making it possible to obtain the performance aspects of a tire defined by the ETRTO as a radial tire, the carcass reinforcement comprises at least one carcass layer, the or each carcass layer comprising carcass filamentary reinforcing elements, each of which extends substantially along a main direction and forms an angle with the circumferential direction of the tire of between 80° and 90° in absolute value.

[0075] The invention will be better understood from the following description, given purely by way of non-limiting example, in conjunction with the drawings in which: [Brief explanation of the drawings]

[0076] [Figure 1] 1 is a top view of a tread of a tire according to a first embodiment of the present invention; [Figure 2] 2 is a schematic diagram of a portion of the tread of the tire of FIG. 1 showing a first cut, a second cut, and a third cut. [Figure 3] FIG. 3 is a view showing the first notch in FIG. 2. [Figure 4]FIG. 3 is a view showing the second cut in FIG. 2. [Figure 5] FIG. 3 is a view showing the third notch in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0077] Reference frames X, Y, Z are shown corresponding to the normal axial (Y), radial (Z) and circumferential (X) directions of the tire, respectively.

[0078] In Figure 1, a tire according to the invention is designated by the general reference number 10. The tire 10 has a substantially toroidal shape about an axis of rotation substantially parallel to an axial direction Y. The tire 10 is intended for passenger cars and is sized 205 / 55 R16. The tire 10 is a summer tire. The tire 10 shown is new, i.e. unworn.

[0079] The tire 10 includes a tread 14 intended to come into contact with the ground during travel. The tire 10 may also include a conventional structure, such as those described in WO 2021 / 250331, WO 2022 / 074341 or WO 2022 / 069819. The tire 10 is obtained by molding a green tire in a mold that includes molding elements, in particular molding elements of the tread 14.

[0080] The tread 14 includes a tread surface 16 that is intended to contact the ground via the tread surface 16 when the tire 10 is running over the ground.

[0081] The tread 14 includes an axially central portion P0 and first and second axially outer portions P1, P2 axially outward from the axially central portion P0 and disposed on both axial sides of the axially central portion P0 with respect to the median plane M of the tire 10.

[0082] The tread 14 includes N>1 circumferential cuts, where in this case N=4 circumferential cuts are designated by reference numerals 20, 22, 24, and 26. Each circumferential cut 20-26 has a depth ranging from 4.0 mm to the tread pattern height Hs, preferably ranging from 5.0 mm to the tread pattern height Hs, and more preferably ranging from 5.5 mm to the tread pattern height Hs. Each depth is 50% or more, preferably 75% or more, and more preferably 90% or more of the tread pattern height. In this case, Hs=7.2 mm, with the depth of each circumferential cut 20, 26 equal to 7.0 mm and the depth of each circumferential cut 22, 24 equal to 7.2 mm.

[0083] Each of the circumferential notches 20 to 26 has a width of 1.0 mm or more, preferably 4.0 mm or more, more preferably 4.0 mm to 20.0 mm. In this case, the width of each of the circumferential notches 20 to 26 is equal to 11.0 mm.

[0084] The axially central portion P0 includes k≧1 circumferential ribs, in this case k=3 circumferential ribs 28, 30, 32. Each of the circumferential ribs 28-32 is separated in the axial direction by axially adjacent first and second circumferential notches among the circumferential notches 20-26. Each of the circumferential ribs 28-32 has a substantially constant length along the axial direction.

[0085] Each circumferential rib 28, 30, 32 includes a transverse cut, designated by reference numerals 38, 40, 42, respectively, formed in said central rib 28, 30, 32. Thus, cuts 38 are formed in the same circumferential rib 28, cuts 40 are formed in the same circumferential rib 30, and cuts 42 are formed in the same circumferential rib 32. Each cut 38 opens into a respective circumferential cut 20, 22. Each cut 40 opens into a respective circumferential cut 22, 24. Each cut 42 opens into a respective circumferential cut 24, 26.

[0086] Each of the cuts 38, 40, 42 has a mean direction that forms an angle of 45° or greater with the circumferential direction X of the tire 10. Each of the cuts 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, in this case equal to 0.4 mm. Each of the cuts 38, 40, 42 has a depth ranging from 2.0 mm to the tread pattern height Hs, preferably ranging from 4.0 mm to the tread pattern height Hs, more preferably ranging from 5.0 mm to the tread pattern height Hs, in this case equal to 5.5 mm.

[0087] 2 shows first, second, and third notches 40, designated by reference numerals 402, 404, and 406, respectively, formed in the circumferential rib 28 separated by the circumferential notches 20, 22. The first notch 402 is circumferentially adjacent to the second notch 404. The second notch 404 is circumferentially adjacent to each of the first and third notches 402, 406. The third notch 406 is circumferentially adjacent to the second notch 404. Each of the first, second, and third notches 40 includes two ends I and J.

[0088] The length l1 of each first cut 402 along the axial direction Y is substantially equal to the length l2 of each second cut 404 along the axial direction Y, and is also substantially equal to the length l3 of each third cut 406 along the axial direction Y. In this case, l1 = l2 = l3 = 28 mm.

[0089] The length L1 of each first cut 402 along the circumferential direction X is different from the length L2 of each second cut 404 along the circumferential direction X. The length L2 of each second cut 404 along the circumferential direction X is different from the length L3 of each third cut 406 along the circumferential direction X. The length L1 of each first cut 402 along the circumferential direction X is different from the length L3 of each third cut 406 along the circumferential direction X. In this example, L1 = 16.3 mm, L2 = 17.9 mm, and L3 = 23.1 mm.

[0090] Each cut 402, 404, 406 opens into each of the circumferential cuts 20, 22 in first and second opening zones Z1, Z2, respectively. An azimuth angle AZ1 of a point of a first opening zone AZ1 of a cut 402, 404, 406 formed in the circumferential rib 28, which in this case is end I, is substantially circumferentially aligned with an azimuth angle AZ2 of a point of a second opening zone AZ2 of another circumferentially adjacent one of the cuts 402, 404, 406 formed in the circumferential rib 28, which in this case is end J of a circumferentially adjacent another one of the cuts 402, 404, 406 formed in the circumferential rib 28.

[0091] Each first notch 402 includes, and in this case is made up of, first, second, and third portions 4021, 4022, and 4023. Each second notch 404 includes, and in this case is made up of, first, second, and third portions 4041, 4042, and 4043. Each third notch 406 includes, and in this case is made up of, first, second, and third portions 4061, 4062, and 4063. Each second portion 4022, 4042, 4062 is disposed axially intermediate the corresponding first portion 4021, 4041, 4061 and the corresponding third portion 4023, 4043, 4063. Each first portion 4021, 4041, 4061 and each second portion 4022, 4042, 4062 is directly joined to one another by a first flexion zone 4024, 4044, 4064, respectively. Each second portion 4022, 4042, 4062 and each third portion 4023, 4043, 4063 is directly joined to one another by a second flexion zone 4025, 4045, 4065, respectively.

[0092] As can be seen from FIGS. 3 to 5, the length L21 of the first portion 4021 of each first cut 402 is different from the length L41 of the first portion 4041 of each second cut 404 and the length L61 of the first portion 4061 of each third cut 406. The length L41 of the first portion 4041 of each second cut 404 is different from the length L61 of the first portion 4061 of each third cut 406. In this case, L21 > L41 > L61, specifically, L21 = 9.41 mm, L41 = 8.75 mm, and L61 = 6.53 mm.

[0093] 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 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. In this case, L22 < L42 < L62, specifically, L22 = 16.11 mm, L42 = 18.35 mm, and L62 = 25.75 mm.

[0094] 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 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. In this case, L23 > L43 > L63, specifically, L23 = 9.41 mm, L43 = 8.75 mm, and L63 = 6.53 mm.

[0095] Note that the length L21 of each first portion 4021 of each first cut 402 is equal to the length L23 of each third portion 4023 of each first cut 402. Also, 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, 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.

[0096] The first, second, and third portions 4021, 4022, and 4023 of the first cut 402 extend along the first, second, and third average directions D21, D22, and D23, respectively. The first, second, and third portions 4041, 4042, and 4043 of the second cut 404 extend along the first, second, and third average directions D41, D42, and D43, respectively. The first, second, and third portions 4021, 4022, and 4023 of the third cut 406 extend along the first, second, and third average directions D61, D62, and D63, respectively.

[0097] The average directions D21, D41, D61 of each first portion 4021, 4041, 4061 and the average directions D23, D43, D63 of each third portion 4023, 4043, 4063 of each first, second and third cut 402, 404, 406 are not parallel to the average directions D22, D42, D62 of the second portions 4022, 4042, 4062 of each first, second and third cut 402, 404, 406, respectively.

[0098] The mean directions D21, D41, and D61 are substantially parallel to one another. The mean directions D22, D42, and D62 are substantially parallel to one another. The mean directions D23, D43, and D63 are substantially parallel to one another.

[0099] The mean direction D21 of the first portion 4021 of the first cut 402 and the mean direction D22 of the second portion 4022 form an angle A2. The mean direction D41 of the first portion 4041 of the second cut 404 and the mean direction D42 of the second portion 4042 form an angle A4. The mean direction D61 of the first portion 4061 of the third cut 406 and the mean direction D62 of the second portion 4062 form an angle A6.

[0100] The mean direction D22 of the second portion 4022 of the first cut 402 and the mean direction D23 of the third portion 4023 form an angle B2. The mean direction D42 of the second portion 4042 of the second cut 404 and the mean direction D43 of the third portion 4043 form an angle B4. The mean direction D62 of the second portion 4062 of the third cut 406 and the mean direction D63 of the third portion 4063 form an angle B6.

[0101] Angles A2, A4, and A6 are substantially equal to one another. Angles B2, B4, and B6 are substantially equal to one another and to angles A2, A4, and A6. In this case, A2=A4=A6=B2=B4=B6=54°.

[0102] The characteristics of the cut 42 are identical to those of the cut 40 described above. The characteristics of the cut 38 can be deduced mutatis mutandis from those of the cut 40 described above by inverting it with respect to a plane passing through the circumferential cut 20, perpendicular to the tire's axis of rotation and parallel to the median plane M. [Explanation of symbols]

[0103] 22 Circumferential cut 24 Circumferential Cut 30 circumferential rib 402 First notch 4021 First Part 4022 Second Part 4023 Third Part 4024 First bending zone 4025 Second Flexion Zone 404 Second cut 4041 First Part 4042 Second Part 4043 Third Part 4044 First Flexion Zone 4045 Second Flexion Zone 406 Third notch 4061 First Part 4062 Second Part 4063 Third Part 4064 First Flexion Zone 4065 Second Flexion Zone AZ1 First Opening Zone AZ2 Second opening zone I end J end L1 Circumferential length of the first notch L2 Circumferential length of the second cut L3 Circumferential length of the third notch l1: Length of the first notch along the axial direction l2: Axial length of the second notch l3 Axial length of the third notch Z1 First Aperture Zone Z2 Second Aperture Zone

Claims

1. A tire (10) having a tread (14) including at least one circumferential rib (28, 30, 32) separated by first and second circumferential cuts (20, 22, 24, 26), and cuts (38, 40, 42) formed in each circumferential rib and opening into each of the first and second circumferential cuts, The notches (38, 40, 42) include first and second notches (402, 404), each of the first and second notches (402, 404) including a first portion (4021, 4041), a second portion (4022, 4042) and a third portion (4023, 4043), and the first portion (4021, 4041) and the second portion (4022, 4042) of each of the first and second notches (402, 404) are directly joined to each other by a first bending zone (4024, 4044). , the second portions (4022, 4042) and the third portions (4023, 4043) of each of the first and second notches (402, 404) are directly joined to each other by second bending zones (4025, 4045), and the second portions (4022, 4042) of each of the first and second notches (402, 404) are respectively positioned axially intermediate the first portions (4021, 4041) and the third portions (4023, 4043) of each of the first and second notches (402, 404); the average directions (D21, D41) of the first portions (4021, 4041) of each of the first and second cuts (402, 404) are not parallel to the average directions (D22, D42) of the second portions (4022, 4042) of each of the first and second cuts (402, 404), respectively; the average directions (D23, D43) of the third portions (4023, 4043) of each of the first and second cuts (402, 404) are not parallel to the average directions (D22, D42) of the second portions (4022, 4042) of each of the first and second cuts (402, 404), respectively; The length (L1) of the first cut (402) along the circumferential direction (X) is different from the length (L2) of the second cut (404) along the circumferential direction (X), each first and second cut (402, 404) opens into each of the first and second circumferential cuts (20, 22, 24, 26) that delimit the circumferential rib (28, 30, 32) in a first and second opening zone (Z1, Z2), and an azimuth angle (AZ1) of a point in the first opening zone (Z1) of the first cut is substantially circumferentially aligned with an azimuth angle (AZ2) of a point in the second opening zone (Z2) of the second cut; an angle (A2) formed by the average direction (D21) of the first portion (4021) of the first cut (402) and the average direction (D22) of the second portion (4022) is substantially equal to an angle (A4) formed by the average direction (D41) of the first portion (4041) of the second cut (404) and the average direction (D42) of the second portion (4042); an angle (B2) formed by the average direction (D22) of the second portion (4022) of the first cut (402) and the average direction (D23) of the third portion (4023) is substantially equal to an angle (B4) formed by the average direction (D42) of the second portion (4042) of the second cut (404) and the average direction (D43) of the third portion (4043); the first portions (4021) of the first cuts (402) extend along a mean direction (D21) substantially parallel to the mean direction (D41) in which the first portions (4041) of the second cuts (404) extend; the second portions (4022) of the first cuts (402) extend along a mean direction (D22) substantially parallel to the mean direction (D42) in which the second portions (4042) of the second cuts (404) extend; the third portion (4023) of the first cut (402) extends along a mean direction (D23) substantially parallel to the mean direction (D43) in which the third portion (4043) of the second cut (404) extends; the length (L21) of the first portion (4021) of the first cut (402) is different from the length (L41) of the first portion (4041) of the second cut (404), and / or the length (L22) of the second portion (4022) of the first cut (402) is different from the length (L42) of the second portion (4042) of the second cut (404), and / or the length (L23) of the third portion (4023) of the first cut (402) is different from the length (L43) of the third portion (4043) of the second cut (404); Tire (10).

2. the length (L1) of the first cut (402) along the circumferential direction is strictly shorter than the length (L2) of the second cut (404) along the circumferential direction; the length (L21) of said first portion (4021) of said first incision (402) is strictly greater than the length (L41) of said first portion (4041) of said second incision (404), and / or the length (L22) of said second portion (4022) of said first incision (402) is strictly less than the length (L42) of said second portion (4042) of said second incision (404), and / or the length (L23) of said third portion (4023) of said first cut (402) is strictly greater than the length (L43) of said third portion (4043) of said second cut (404); A tire (10) according to claim 1.

3. The length (l1) of the first cut (402) along the axial direction (Y) is substantially equal to the length (l2) of the second cut (404) along the axial direction (Y). A tire (10) according to claim 1 or 2.

4. the angles (A2, A4) formed by the average directions (D21, D41) of the first portions (4021, 4041) of each of the first and second cuts (402, 404) and the average directions (D22, D42) of the second portions (4022, 4042) of each of the first and second cuts (402, 404) are substantially equal to the angles (B2, B4) formed by the average directions (D22, D42) of the second portions (4022, 4042) of each of the first and second cuts (402, 404) and the average directions (D23, D43) of the third portions (4023, 4043); A tire (10) according to any one of claims 1 to 3.

5. the length (L21) of the first portion (4021) of the first cut (402) is equal to the length (L23) of the third portion (4023) of the first cut (402); and / or - said length (L41) of said first portion (4042) of said second cut (404) is equal to said length (L43) of said third portion (4043) of said second cut (404); A tire (10) according to any one of claims 1 to 4.

6. the first and second notches (402, 404) are circumferentially adjacent; A tire (10) according to any one of claims 1 to 5.

7. the cuts (38, 40, 42) include a third cut (406), the third cut (406) including first, second and third portions (4061, 4062, 4063), the first portion (4061) and the second portion (4062) of the third cut (406) being directly joined to one another by a first bending zone (4064), the second portion (4062) and the third portion (4063) of the third cut (406) being directly joined to one another by a second bending zone (4065), and the second portion (4062) of the third cut (406) being positioned axially intermediate the first and third portions (4061, 4063) of the third cut (406); the average direction (D61) of the first portion (4061) of the third cut (406) is not parallel to the average direction (D62) of the second portion (4062) of the third cut (406); an average direction (D63) of the third portion (4063) of the third cut (406) is not parallel to an average direction (D62) of the second portion (4062) of the third cut (406); a length (L3) of the third cut (406) along the circumferential direction (X) is different from lengths (L1, L2) of the first and second cuts (402, 404) along the circumferential direction (X); the third cut (406) opens into each of the first and second circumferential cuts (20, 22, 24, 26) that delimit the circumferential ribs (28, 30, 32) in first and second open zones (Z1, Z2), and an azimuth angle (AZ1) of a point in the first open zone (Z1) of the third cut (406) is substantially circumferentially aligned with an azimuth angle (AZ2) of a point in the second open zone (Z2) of one of the first and second cuts (402, 404); an angle (A6) formed by the average direction (D61) of the first portion (4061) of the third cut (406) and the average direction (D62) of the second portion (4062) is substantially equal to each angle (A2, A4) formed by the average directions (D21, D41) of the first portion (4021, 4041) of each first and second cut (402, 404) and the average directions (D22, D42) of the second portion (4022, 4042); an angle (B6) formed by the average direction (D62) of the second portion (4062) of the third cut (406) and the average direction (D63) of the third portion (4063) is substantially equal to angles (B2, B4) formed by the average directions (D22, D42) of the second portions (4022, 4042) of each of the first and second cuts (402, 404) and the average directions (D23, D43) of the third portion (4043); the first portion (4061) of the third cut (406) extends along an average direction (D61) substantially parallel to the average directions (D21, D41) in which the first portions (4021, 4041) of each of the first and second cuts (402, 404) extend; the second portion (4062) of the third cut (406) extends along an average direction (D62) substantially parallel to the average directions (D22, D42) in which the second portions (4022, 4042) of each of the first and second cuts (402, 404) extend; the third portion (4063) of the third cut (406) extends along an average direction (D63) substantially parallel to the average directions (D23, D43) in which the third portions (4023, 4043) of each of the first and second cuts (402, 404) extend; The lengths (L21, L41, L61) of the first portions (4021, 4041, 4061) of each of the first, second and third cuts (402, 404, 406) are different from the lengths (L21, L41, L61) of the first portions (4021, 4041, 4061) of each of the other cuts among the first, second and third cuts (402, 404, 406), and / or the lengths (L22, L42, L62) of the second portions (4022, 4042, 4062) of each of the first, second and third cuts (402, 404, 406) are different from the lengths (L21, L41, L61) of the first portions (4021, 4041, 4061) of each of the other cuts among the first, second and third cuts (402, 404, 406). the lengths (L22, L42, L62) of the second portions (4022, 4042, 4062) of each of the other first, second, and third notches (402, 404, 406) are different from the lengths (L23, L43, L63) of the third portions (4023, 4043, 4063) of each of the first, second, and third notches (402, 404, 406), and / or the lengths (L23, L43, L63) of the third portions (4023, 4043, 4063) of each of the other first, second, and third notches (402, 404, 406), are different from the lengths (L23, L43, L63) of the third portions (4023, 4043, 4063) of each of the other first, second, and third notches (402, 404, 406), A tire (10) according to any one of claims 1 to 6.

8. the length (L1) of the first cut (402) along the circumferential direction is strictly shorter than the length (L2) of the second cut (404) along the circumferential direction, and the length (L2) of the second cut (404) along the circumferential direction is strictly shorter than the length (L3) of the third cut (406) along the circumferential direction; the length (L21) of the first portion (4021) of the first incision (402) is strictly greater than the length (L41) of the first portion (4041) of the second incision (404), and the length (L41) of the first portion (4041) of the second incision (404) is strictly greater than the length (L61) of the first portion (4061) of the third incision (406); and / or the length (L22) of the second portion (4022) of the first incision (402) is strictly less than the length (L42) of the second portion (4042) of the second incision (404), and the length (L42) of the second portion (4042) of the second incision (404) is strictly less than the length (L62) of the second portion (4062) of the third incision (406); and / or the length (L23) of said third portion (4023) of said first cut (402) is strictly greater than the length (L43) of said third portion (4043) of said second cut (404), and the length (L43) of said third portion (4043) of said second cut (404) is strictly greater than the length (L63) of said third portion (4063) of said third cut (406); A tire (10) according to claim 7.

9. a length (l3) of the third notch (406) along the axial direction (Y) is substantially equal to lengths (l1, l2) of each of the first notch (402) and the second notch (404) along the axial direction (Y); A tire (10) according to claim 7 or 8.

10. an angle (A6) formed by the average direction (D61) of the first portion (4061) of the third cut (406) and the average direction (D62) of the second portion (4062) of the third cut (406) is substantially equal to an angle (B6) formed by the average direction (D62) of the second portion (4062) of the third cut (406) and the average direction (D63) of the third portion (4063); A tire (10) according to any one of claims 7 to 9.

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

12. the third notch (406) is circumferentially adjacent to at least one of the first and second notches (402, 404), and preferably each of the first, second and third notches (402, 404, 406) is circumferentially adjacent to at least one other of the first, second and third notches (402, 404, 406); A tire (10) according to any one of claims 7 to 11.

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