Tires with an improved tread pattern

Abstract

According to an aspect of the present invention, a vehicle tire having a tread is provided. The tread includes a set of continuous blocks arranged along the outer circumference of the tire, the set of continuous blocks comprising a first subset of blocks arranged according to a first pitch having a first pitch length. The tread further comprises a plurality of first grooves arranged across the outer circumference of the tire, each of the plurality of first grooves being positioned between two blocks of the set of continuous blocks. Each first block of the first subset of the set of continuous blocks comprises a first sipe positioned within the first block, the first sipe comprising a first projection of the first sipe, which begins at the bottom of the first sipe and extends radially outward.

Description

[Technical Field]

[0001] This invention relates to vehicle tires. One possible application of the disclosed tire relates to an all-season tire intended for use on passenger cars or commercial vans. This disclosure can also be applied to other tires, such as winter tires, summer tires, or tires for off-road use. [Background technology]

[0002] All-season tires (used here as a typical example for readability) are known for providing good grip on snow-covered roads while also offering good performance on dry and wet roads. Such tires are intended for year-round use and do not require switching between summer and winter tires.

[0003] For example, all-season tires are known to have grooves that extend from the center of the tire tread, i.e., from the tire's equatorial plane, toward the tire's shoulder (sometimes called the "shoulder portion" or "side portion"). These grooves typically extend substantially axially and are configured to deliver water outward from the tire's contact patch with the road surface in order to provide contact between the tire blocks and the road surface. Contact between the blocks and the road is necessary to provide lateral road holding and, furthermore, to provide friction that allows the driver to control the vehicle's movement through acceleration, braking, and / or steering.

[0004] Furthermore, all-season tires are known to have sipes that enhance traction on snow-covered surfaces. However, sipes reduce the rigidity of the tread blocks, impairing the tire's braking performance on dry ground.

[0005] Furthermore, tread blocks often vary in width between individual blocks, which may have different widths in different sections, or across the outer circumference of the tire, where various blocks of different widths may be present. This variation in block width results in an unbalanced distribution of block stiffness on the tread, which in turn leads to an uneven distribution of wear energy and contact pressure, resulting in a deterioration of tire performance.

[0006] Accordingly, an object of the present invention is to provide a tire having sipes and blocks of different widths and inclination angles, which may be beneficial for several reasons, while avoiding the drawbacks of uneven stiffness distribution across the axial extension of the tread and the outer circumference of the tire. [Overview of the Initiative]

[0007] This objective is achieved by providing an improved vehicle tire as described in the independent claim. Further embodiments are described in the dependent claims.

[0008] According to an aspect of the present invention, a vehicle tire having a tread is provided. The tread includes a set of continuous blocks arranged along the outer circumference of the tire, the set of continuous blocks comprising a first subset of blocks arranged according to a first pitch having a first pitch length. The tread further comprises a plurality of first grooves arranged across the outer circumference of the tire, each of the plurality of first grooves being positioned between two blocks of the set of continuous blocks. Each first block of the first subset of the set of continuous blocks comprises a first sipe positioned within the first block, the first sipe comprising a first projection of the first sipe, which begins at the bottom of the first sipe and extends radially outward.

[0009] Such tires enable good traction on snow-covered ground by incorporating sipes intended to catch snow and additional edges intended to bite into the snow and provide traction on the road surface.

[0010] Furthermore, a projection is provided at the bottom of the sipe. This projection is intended to locally reinforce the block at the location of the projection, which is achieved by providing additional material. Advantageous locations for the projection can be found in preferred embodiments. Generally, the projection may be provided in a position intended to provide a hinge function to the block. That is, if the block is intended to bend around a certain part, for example between a first part and a second part, the projection may be provided between these two parts to locally reinforce the block between the parts, such that the bending of the block around the projection is precedent. By controlling the bending behavior of the block, a more uniformly distributed contact pressure of the block on the ground can be achieved, which increases tire grip and, at the same time, reduces wear, which is beneficial for tire wear and therefore durability.

[0011] Alternatively, the protrusions may be provided in locations where the block may require additional reinforcement, for example, in relatively narrow sections of the block. In this case, the protrusions may reinforce areas with low structural rigidity, such as sections of the block with a small angle of inclination relative to the circumferential direction. This improves the overall distribution of rigidity across the width of the tread, resulting in a more uniform distribution of contact pressure with the advantages described above.

[0012] The protrusions of narrow block sections can be particularly beneficial for blocks with short pitch lengths. In this case, the distribution of block stiffness across the entire pitch can be improved, which in turn benefits the overall grip of the tire and provides improved vehicle handling, especially on dry and wet surfaces, during braking, acceleration, and steering. [Brief explanation of the drawing]

[0013] [Figure 1] A schematic diagram of a vehicle tire according to this disclosure is shown. [Figure 2] The half-tread profile of the tire as disclosed herein is shown. [Figure 3A]Shows various possible shapes of the sipe according to the present disclosure. [Figure 3B] Shows various possible shapes of the sipe according to the present disclosure. [Figure 3C] Shows various possible shapes of the sipe according to the present disclosure. [Figure 3D] Shows various possible shapes of the sipe according to the present disclosure. [Figure 3E] Shows various possible shapes of the sipe according to the present disclosure. [Figure 3F] Shows various possible shapes of the sipe according to the present disclosure. [Figure 3G] Shows various possible shapes of the sipe according to the present disclosure. [Figure 4] Shows the semi - tread profile of a tire having a plurality of pitches with different pitch lengths according to the present disclosure. [Figure 5] Shows the inside of the first sipe according to the present disclosure. [Figure 6] Shows the inside of the second sipe according to the present disclosure. [Figure 7] Shows an enlarged view of a block showing possible positions of the protrusions according to the present disclosure. [Figure 8] Shows an exemplary embodiment of a V - shaped directional tread pattern according to the present disclosure. [Figure 9] Shows an exemplary embodiment of an S - shaped tread pattern according to the present disclosure. [Figure 10] Shows a blade for forming a sipe according to the present disclosure.

MODE FOR CARRYING OUT THE INVENTION

[0014] The object of the present invention is achieved by providing at least one protrusion that extends from the bottom of the sipe and extends radially outward.

[0015] These protrusions are intended to locally reinforce the blocks, thereby significantly reducing block deformation in response to stress. This is particularly beneficial in areas of the blocks that are not inherently very rigid, such as narrow block sections, especially when the pitch length is short. By locally reinforcing the blocks, a more uniform distribution of stiffness can be achieved across the entire tread, which has a beneficial effect on tire performance.

[0016] "Pitch" can be thought of as the geometric part of a pattern that repeats across the entire circumference of the tire.

[0017] "Pitch length" can be defined, in particular, as the arc length (measured on the outer circumference of the tire) between one point belonging to the pitch and its homologous point, and therefore includes both the rubber portion and the air gap portion.

[0018] Therefore, the "pitch length" corresponds to the sum of the block width and the width of one adjacent first groove, only if the width is calculated along the outer circumference of the tire and not perpendicular to the groove.

[0019] Furthermore, since the pitch length includes both the rubber portion and the void portion, an increase in block width does not necessarily correspond to an increase in pitch length (i.e., the block width may change, but this can be compensated for by the void width to maintain the same pitch length, and vice versa).

[0020] For example, if the block stiffness is distributed more uniformly across the pattern, the contact pressure of the tire on the ground can be distributed more uniformly. Such a uniform distribution of contact pressure allows for improved overall traction of the tire on various types of surfaces, as well as improved wear performance. In other words, wear energy can be distributed more uniformly across the entire tread, resulting in more uniform tire wear. This can lead to an extended tire lifecycle.

[0021] This disclosure further includes useful methods for positioning protrusions within a sipe. For example, it may be useful to provide two protrusions per sipe so that the protrusions, together with adjacent less rigid portions, can substantially act as hinge portions that allow the block to bend at a desired position. For example, the protrusions may be located between the shoulder portion and the middle portion of the block, and between the middle portion and the central portion of the block. Furthermore, for blocks with smaller pitch lengths, additional protrusions can be provided in the narrowest portion of the block, which is usually the central portion, because this narrowest portion of the block generally exhibits the lowest rigidity. By selectively providing additional protrusions in blocks with smaller pitch lengths in this way, a particularly useful rigidity distribution is obtained, and thus a specific improvement in the traction and wear performance of the tire is obtained.

[0022] Figure 1 is a schematic diagram of a vehicle tire according to this disclosure.

[0023] According to Figure 1, the tire 100 comprises a tread 110. The tread comprises a set of continuous blocks 10 and a plurality of grooves 12, where each groove 12 is positioned between two blocks 10 of the set of continuous blocks. Furthermore, sipes 14 may be positioned within each of the set of continuous blocks 10.

[0024] The blocks may be arranged continuously in the circumferential direction 120 of the tire.

[0025] A "groove" represents an indentation in the tread pattern. The width of the grooves may vary; for example, a first groove may be wider than a second groove, or they may be the same width or even narrower. For example, the width of a groove may be at least 2 mm. The width of a single groove does not necessarily have to be constant. For example, a groove may have a wider width towards the opening of the tread pattern and a narrower width radially inward. The depth of the grooves may also vary; in some cases, the grooves may extend to the total depth of the tread (the total depth of the tread is the maximum radially measured distance between the outermost radial portion of the tire and the bottom of the deepest groove), but this is not necessarily required. For example, a depth of at least 1 mm, preferably at least 3 mm, is conceivable.

[0026] "Sipes" also refer to cuts in the tread pattern. In this specification, "sipes" refer to cuts within a block, rather than "grooves" separating the blocks. For example, the width of a sipe may be smaller than the width of a groove, for example, less than 2 mm. As with grooves, the width of a sipe does not need to be constant; means can be applied to allow it to widen towards the opening of the tread pattern and narrow radially inward. The depth of a sipe may also vary, and in some cases, a sipe may extend to the full depth of the tread block, but this is not necessarily required. For example, a depth of at least 1 mm, preferably at least 20% of the depth of the first groove, is conceivable.

[0027] In the context of this disclosure, “circumferential direction” 120 means a direction parallel to the direction in which the tire normally rolls, i.e., a direction perpendicular to the axial direction 130 which is parallel to the tangential direction to the outer circumference of the tire. With respect to Figure 1, the circumferential direction 120 is therefore a direction that lies in a plane parallel to the yz plane.

[0028] In the context of this disclosure, “axial direction” 130 means the direction parallel to the axis of the vehicle to which the tire is normally mounted. Thus, according to Figure 1, the axial direction 130 is parallel to the x-axis and therefore perpendicular to the yz-plane.

[0029] In the context of this disclosure, “radial direction” 140 means the direction perpendicular to the axial direction. The radial direction is parallel to the connection between the center 150 of the tire and the tread surface. Thus, the radial direction lies in a plane parallel to the yz plane and substantially perpendicular to the axial direction 130 and the circumferential direction 120.

[0030] In the context of this disclosure, “equator plane” refers to a plane perpendicular to the axial direction 130 and cutting the cross-sectional width of the tire into two equal halves. Thus, the equatorial plane is parallel to the yz plane and corresponds to the widthwise centerline of the tread.

[0031] Furthermore, any numerical angle given herein should be considered an absolute value, that is, not limited to the direction of each angle.

[0032] Figure 2 shows the half-tread profile of the tire according to this disclosure.

[0033] As shown in Figure 2, the tire tread comprises a set of continuous blocks 10 arranged along the outer circumference of the tire. In the context of this disclosure, “continuous blocks” means that the tread comprises a plurality of blocks that are continuous with one another across the outer circumference of the tire. While the present invention is preferably provided for all blocks of a tire, some blocks that may be located between the individual blocks 10 of the set of continuous blocks may not have sipes according to the present invention.

[0034] In some embodiments described in more detail elsewhere in this specification, the tread comprises additional blocks on the other side of the tire's equatorial plane 16. In some embodiments described elsewhere in this specification, these additional blocks may have an axisymmetric configuration with respect to the block 10 shown in Figure 2, thereby the overall pattern being V-shaped. In other embodiments described elsewhere in this specification, the additional blocks may be point-symmetric, and the overall pattern may be S-shaped. In any case, this disclosure is not intended for any particular orientation of the blocks and can be applied to blocks of various shapes and orientations.

[0035] Furthermore, although this disclosure describes a tread pattern that is substantially symmetrical, i.e., having the same or similar tread configuration on both sides of the equatorial plane, it will be understood that the concepts described herein can also be applied to asymmetrical tread patterns, i.e., patterns having substantially different tread configurations on both sides of the equatorial plane of the tire.

[0036] Generally, the block 10 is intended to provide contact with the ground when the tire is rolling. The edges and surface of the block are configured to provide frictional force between the tire and the ground for grip, enabling general road holding, as well as the driver's control of the vehicle's movement through acceleration, braking, or steering.

[0037] As shown in Figure 2, the tread further comprises a plurality of first grooves 12 arranged around the outer circumference of the tire, each of which is positioned between two blocks 10 of a set of continuous blocks. Preferably, the grooves 12 begin near the equatorial plane 16 of the tire, extend toward the shoulder end of the tread, and open at the outer edge of the tire. The grooves 12 are generally defined by adjacent blocks 10.

[0038] The primary purpose of the grooves 12 is to guide water along the grooves 12 toward the tire's shoulder as the tire rolls on the road surface, thereby draining water from the contact patch. Thus, the grooves 12 improve tire performance, especially on wet road surfaces. Furthermore, since the grooves define continuous blocks, they also provide edges for the blocks to improve snow performance. In addition, the grooves allow for greater flexibility of the tread elements, thus improving wear performance, resulting in reduced slippage of the blocks on the ground and a decrease in wear-inducing effects.

[0039] As shown in Figure 2, the tread may further comprise a plurality of second grooves 20, each of which may be substantially circumferentially arranged. In some embodiments, each second groove 20 may be arranged, for example, as a substantially straight line slightly inclined with respect to the circumferential direction, and in other embodiments, for example, as shown in Figure 2, each second groove 20 may be arranged in a zigzag shape including, for example, three different inclined portions. Such a zigzag configuration of the second grooves 20 allows for partial interruption of the tire's deformation and sliding behavior, thus improving the distribution of wear energy across the entire axial extension of the block 10.

[0040] The second groove may generally serve to separate the shoulder portion of the block 10 from the portion of the block 10 that is positioned more inward in an axial view, i.e., closer to the tire's equatorial plane 16. For example, during acceleration or braking, the shoulder portion of the block 10 is particularly susceptible to deformation because it is positioned substantially perpendicular to the circumferential direction of the tire. This can lead to deformation of the block 10 in the shoulder portion. Therefore, it is desirable to mechanically separate the shoulder portion from the portion of the block 10 that is positioned more inward in an axial direction in order to ensure good steering performance and lateral road holding during braking and acceleration. This separation may preferably be achieved by providing a second groove 20 between them. In this way, the portion positioned more inward in an axial direction still provides lateral road holding and steering performance despite the deformation of the shoulder portion. A wider second groove improves the separation effect compared to a narrower second groove.

[0041] As shown in Figure 2, the tread may further comprise a plurality of sipes 14. In the illustrated tread pattern, each of the plurality of sipes 14 may extend substantially along the shape of the block 10. However, other arrangements and shapes of sipes on the outer tread surface are also possible, such as corrugated or zigzag shapes. Sipes do not necessarily have to follow the shape of the block. For example, sipes may be included only along a portion of the shape of the block, or they may have a different angle of inclination with respect to the circumferential direction than the underlying block or portion of the block. Also, some sipes may have walls that extend radially toward the center of the tire, while some sipes may have corrugated, zigzag shapes, etc., in the radial direction. Furthermore, such sipes may be inclined with respect to the radial direction. Some sipes may have projections near the bottom of the sipe. Some examples of sipe shapes will be described with reference to Figures 3A to 3G.

[0042] The 14 sipes can trap snow within them, providing an additional edge to the tread. This improves traction on snow-covered ground.

[0043] In some embodiments, the multiple sipes 14 may define an edge component (EI) corresponding to the ratio of the sum of the axial protrusion lengths (SAP) of the multiple sipes to the outer circumference (C) of the tread, thereby,

[0044]

number

[0045] The tire circumference C is measured at the outermost radial ring of the inflated tire. The same specifications as those described below for tire footprint measurement apply to the inflation pressure and ambient temperature.

[0046] A high edge component provides better ability to capture snow, thereby improving the tire's traction on snow-covered ground. However, a high edge component also results in low block rigidity, which generally deteriorates the braking / acceleration performance on dry ground. When the edge component is within any of the above ranges, the balance between traction on snow-covered ground and braking / acceleration performance on dry ground is particularly good.

[0047] The tire according to FIG. 2 further has a void volume that is the volume of all the grooves, sipes, and recesses provided in the tread, and the volume of the rubber provided in the tread, and these may together occupy the total volume of the tread. That is, if the total volume of the tire is V T and the void volume is V V and the rubber volume is V R then the total volume V T is V T =V V +V R In a preferred embodiment, the ratio V V of the void volume V R to the rubber volume V V / V R may be at least 0.20 and at most 0.4%. Preferably, the ratio V V / V R may be at least 0.24 and at most 0.37, more preferably at least 0.28 and at most 0.35. The ratio V V / VR is directly related to the rigidity of the tread profile. Therefore, the higher the ratio V V / V R , the more voids there are in the tread, which improves snow performance by reducing the rigidity of the tread. The lower the ratio V V / V R , the more rubber there is in the tread, which improves braking performance by increasing the rigidity. A specific range of void-to-rubber ratio provides an optimal trade-off between snow performance and dry performance, and provides a tire that exhibits good braking performance on dry ground and good traction on snow-covered ground.

[0048] According to Figure 2, block 10 may comprise a first portion 101 positioned in the shoulder region of the tire, and a second portion 102 positioned axially inward of the first portion 101 of block 10. Block 10 may further comprise a third portion 103 positioned axially inward of the second portion 102 of block 10.

[0049] Figures 3A to 3G show various possible shapes of sipes according to this disclosure.

[0050] As shown in Figure 3A, the sipe may be provided as a straight line having two parallel planar walls. Such a sipe provides particularly low rigidity to the block and therefore increases the tire's traction on snow.

[0051] Alternatively, as shown in Figure 3B, the sipe may have a corrugated shape such that the opposing walls are parallel but not planar, exhibiting several waves along the block surface. Such a sipe generally corresponds to the sipe in Figure 3A, but has a substantially sinusoidal shape. Therefore, it exhibits higher rigidity, and because the amount of sipe area increases, the likelihood of the sipe walls mechanically interlocking under high strain increases, thus improving damping performance.

[0052] Alternatively, as shown in Figure 3C, the sipe may have radial waves, that is, waves arranged along the radial direction, and the waves have a periodic shape. This sipe shape also exhibits higher rigidity, and because the amount of sipe area increases, the likelihood of the sipe walls mechanically engaging under high strain increases, and therefore the braking performance is improved.

[0053] As a variation, as shown in Figure 3D, the waveform shape and periodicity may differ across the extension of the sipe. This sipe shape similarly exhibits higher rigidity, and because the amount of sipe area increases, the likelihood of the sipe walls mechanically engaging under high strain increases, thus improving braking performance.

[0054] Alternatively, as shown in Figure 3E, a sipe may be provided that has a two-dimensional waveform shape, that is, a wave arranged along the extension of the sipe and a wave along the radial direction.

[0055] Alternatively, as shown in Figure 3F, sipes with a shape similar to that shown in Figure 3E may be provided, but the top forms a straight line, and the corrugated shape begins only radially downward on the outer surface of the block.

[0056] The sipes in Figures 3E and 3F have similar shapes. As a result, the large portion of the rubber area interlocks under high strain, contributing to high shear stress and then high friction, thereby increasing block stiffness, and thus increasing the stiffness of the resulting block. In this way, since the sipes still provide some degree of deformability, dry and wet performance can be improved while maintaining good snow performance.

[0057] Alternatively, as shown in Figure 3G, the sipe may have one or more preferably elliptical recesses arranged along the extension of the sipe. Another solution involves introducing several localized protrusions on one side of the sipe. In this way, the interlocking points can be localized to specific parts of the sipe itself, allowing for an improvement in the stiffness distribution.

[0058] These are some exemplary shapes of sipes, but additional shapes are possible. Combinations of several sipe shapes are also conceivable, for example, one wall having one shape and another having a different shape, or the shape of a sipe changing along its extension.

[0059] Figure 4 shows the half-tread profiles of a tire having multiple pitches with different pitch lengths according to this disclosure.

[0060] According to Figure 4, the set of continuous blocks 10 may comprise a first subset of blocks 310 arranged according to a first pitch having a first pitch length. Each block 310 of the first subset of blocks 310 may comprise a first portion 312 located in the shoulder region of the tire and a second portion 314 located axially inward of the first portion 312 of the block 310. The block 310 may further comprise a third portion 316 located axially inward of the second portion 314 of the block 310. Each block 310 of the first subset of blocks 310 may further comprise a first sipe 318.

[0061] As shown in Figure 4, the set of continuous blocks 10 may further comprise a second subset of blocks 320 arranged according to a second pitch having a second pitch length, the second pitch length being smaller than the first pitch length. Each block 320 of the second subset of blocks 320 may comprise a first portion 322 located in the shoulder region of the tire, and a second portion 324 located axially inward of the first portion 322 of the block 320. The block 320 may further comprise a third portion 326 located axially inward of the second portion 324 of the block 320. Each block 320 of the second subset of blocks 320 may further comprise a second sipe 328.

[0062] As shown in Figure 4, the set of continuous blocks 10 may further include a third subset of blocks 330 arranged according to a third pitch having a third pitch length, the third pitch length being smaller than the second pitch length. Each block 330 of the third subset of blocks 330 may comprise a first portion 332 located in the shoulder region of the tire, and a second portion 334 located axially inward of the first portion 332 of the block 330. The block 330 may further comprise a third portion 336 located axially inward of the second portion 334 of the block 330. Each block 330 of the third subset of blocks 330 may further comprise a third sipe 338.

[0063] In some embodiments, the first pitch length may be the maximum pitch length of the tire. In some embodiments, the tread may have only one pitch length, which is the first pitch length, i.e., all blocks and associated circumferential distances have equivalent extensions in the circumferential direction. In other embodiments, the tread may have two pitch lengths, i.e., a first pitch length and a second pitch length. In this case, the first pitch length may be the maximum pitch length, and the second pitch length may be smaller than the first pitch length. Preferably, the second pitch length may be 90% or less of the first pitch length. More than two pitches, for example, three or more, can also be applied.

[0064] As shown in Figure 4, at least one third portion 316, 326, 336 of the first block 310, the second block 320, or the third block 330 may have an axial extension of at least 25% and up to 40% of the half-footprint width of the tire. Thus, the third portions 316, 326, 336 preferably begin adjacent to the equatorial plane 16 of the tire and extend axially outward to a width of 25% to 40% of the half-footprint width of the tire.

[0065] At least one of the second portions 314, 324, 334 of the first block 310, the second block 320, or the third block 330 may have an axial extension of at least 25% and up to 55% of the half-footprint width of the tire. Thus, the second portions 314, 324, 334 preferably begin from the axially outer end of the third portion 316, 326, 336 and extend axially outward to a width of 65% to 80% of the half-footprint width of the tire.

[0066] At least one of the first portions 312, 322, 332 of the first block 310, the second block 320, or the third block 330 may have an axial extension of at least 20% and up to 35% of the half-footprint width of the tire. Thus, the first portions 312, 322, 332 preferably begin at the axial outer end of the second portions 314, 324, 334 and extend axially outward to the axial outer end of the tire, i.e., cover the entire half-footprint width axially outward from the second portions 314, 324, 334.

[0067] In some embodiments, the separation between at least two parts of at least one of the first block or the second block is - One or more recesses on one or more edges of the block, - Change in the angle of inclination of the blocks relative to the circumferential direction of the tire, - Direction or magnitude of the curvature of the block, - Gradual increase or decrease in the width of the chamfered area. - Grooves extending substantially circumferentially through the block, or -The combination may be defined by any of these combinations.

[0068] For example, as shown in Figure 4, the recess 350 may separate the second portion 314 of block 310 from the third portion 316 of block 310. Furthermore, the recess 340 may separate the first portion 312 of block 310 from the second portion 314 of block 310.

[0069] Alternatively, other means of separation between the edge portions are also possible. For example, as shown in Figure 4, a groove 20 extending substantially circumferentially through block 310 may separate the first portion 312 from the second portion 314. Although such a groove is shown only in Figure 4 to separate the first portions 312, 322, 332 from the second portions 314, 324, 334, a similar groove may be located between the second portions 314, 324, 334 and the third portions 316, 326, 336.

[0070] Furthermore, although only the recesses 340 and grooves 20 are shown as means for separating adjacent edge portions in Figure 4, other means such as gradually increasing or decreasing the width of the chamfer can be used.

[0071] In the context of this disclosure, “chamfer” means the inclined side wall of a block extending radially inward from the outer block surface. The wall is inclined such that the width of the block, measured circumferentially, increases toward the bottom of the groove. Each chamfer is defined by its height and width. The chamfer height may correspond to the distance, measured radially, between the outer block surface and the radially innermost edge of the inclined wall. The chamfer height (= distance between the outer block surface and the radially innermost edge of the inclined wall) is typically lower than the total height of the block, for example, up to 50% or less of the total height of the block. The chamfer width may be measured perpendicular to the block and corresponds to the width of the inclined chamfer wall when it protrudes above the outer tread surface.

[0072] Alternatively, changes in the direction or magnitude of the curvature of each edge can be used, namely changes between concave and convex curvature, as well as increases or decreases in edge curvature, to separate two adjacent edge portions.

[0073] Furthermore, the angle of inclination of each block relative to the circumferential direction of the tire can be used to determine the separation between block sections.

[0074] According to one approach, the angle of inclination of each part of the block is determined by the angle between (i) a tangent applied to the trailing edge of the block and (ii) the circumferential direction of the tire. If each part of the block has a chamfer, the tangent is applied to the outermost circumferential end of the block (negligible for the width and shape of the chamfer). This approach can be used when each part of the block is formed continuously or substantially continuously, i.e., without substantial circumferential cuts in between, and exhibits discontinuities in its inclination with respect to the circumferential direction of the tire, e.g., significant changes, on the leading and trailing edges. By connecting the two discontinuities, the block is separated into two respective parts.

[0075] Preferably, the inclination angles of the first portions 312, 322, and 332 (i.e., the inclination angles of either the leading edge or trailing edge of each portion of the block with respect to the circumferential direction) may be at least 65 degrees and a maximum of 90 degrees with respect to the circumferential direction, preferably 75 degrees and a maximum of 90 degrees with respect to the circumferential direction, and more preferably at least 85 degrees and a maximum of 90 degrees with respect to the circumferential direction. The inclination angle of the second portion 102 may be at least 50 degrees and a maximum of 65 degrees with respect to the circumferential direction. Preferably, the inclination angles of the second portions 314, 324, and 334 may be at least 50 degrees and a maximum of 60 degrees with respect to the circumferential direction. The inclination angle of the third portion 103 may be at least 20 degrees and a maximum of 50 degrees with respect to the circumferential direction. Preferably, the inclination angles of the third portions 316, 326, and 336 may be at least 30 degrees and a maximum of 50 degrees with respect to the circumferential direction.

[0076] According to another approach that may be used when neither the leading nor trailing edge exhibits discontinuity in the inclination of the tire with respect to the circumferential direction, the separation between block portions is preferably determined according to the axial extension of the footprint width as described above in relation to Figure 4, the recess of each edge, the direction or magnitude of the curvature of each edge, the gradual increase or decrease in the chamfer width, or grooves that substantially extend through the block in the circumferential direction.

[0077] More preferably, in this approach, the inclination angle may be used in addition to one or more of the aforementioned criteria. For example, the third portions 316, 326, 336, which begin adjacent to the equatorial plane of the tire and extend axially outward to a width of 25% to 40% of the half-footprint width of the illustrated tire, have an inclination angle of at least 20 degrees and a maximum of 50 degrees with respect to the circumferential direction for at least one of the possible extensions within this range, which may be at least 30 degrees and a maximum of 50 degrees with respect to the circumferential direction. Similarly, the second portions 314, 324, 334, which begin at the axially outward end of the third portion and extend axially outward to a width of 65% to 80% of the half-footprint width of the tire, exhibit an inclination angle of at least 50 degrees and a maximum of 65 degrees with respect to the circumferential direction, which may be at least 50 degrees and a maximum of 60 degrees. Similarly, the first portions 312, 322, 332, which begin at the axial outer end of the second portion and extend axially outward to the axial outer end of the tire, exhibit an inclination angle of at least 65 degrees and a maximum of 90 degrees with respect to the circumferential direction, preferably 75 degrees and a maximum of 90 degrees with respect to the circumferential direction, and more preferably at least 85 degrees and a maximum of 90 degrees with respect to the circumferential direction.

[0078] In the context of this disclosure, “leading edge” may also be referred to as “traction edge,” and refers to the edge of a block that primarily responds to longitudinal traction forces applied to the tire. Typically, the “leading edge” is longer than the side edge of the block and is the edge of the block that first encounters the ground when the tire block, rolling in the preferred rolling direction, enters the tire-to-ground contact patch.

[0079] The "trailing edge," sometimes called the "braking edge," refers to the edge of the tire block that primarily responds to longitudinal braking forces applied to the tire. Typically, the "trailing edge" is the edge of the block that is longer than the side edge and is the last edge that loses contact with the ground when the tire block, rolling in the preferred direction of rolling, leaves the tire's contact patch with the ground.

[0080] Furthermore, various combinations of means for separating the edge portions are also possible. For example, Figure 4 shows a combination of a recess 340 and a groove 20 for separating the first portions 312, 322, 332 from the second portions 314, 324, 334, and there are other possible combinations.

[0081] Figure 5 shows the inside of the first sipe according to this disclosure.

[0082] As shown in Figure 5, the first sipe 318 may include a first projection 22 that begins at the bottom of the first sipe and extends radially outward. The first projection 22 of the first sipe 318 may be located between the first portion 312 and the second portion 314 of the first block 310. That is, in some embodiments, the first projection 22 of the first sipe 318 may be located adjacent to a second groove 20 that extends substantially circumferentially through the block 310.

[0083] In some embodiments, the first sipe 318 may include a second projection 24 that begins at the bottom of the first sipe 318 and extends radially outward. The second projection 24 of the first sipe 318 may be located between the second portion 314 and the third portion 316 of the first block 310.

[0084] As described above, the first sipe 318 may preferably be located in the first block 310 of the first subset of blocks, i.e., the block having the maximum pitch length.

[0085] Furthermore, as described above, the second block 320 of the second subset of block 320 may include a second sipe 328.

[0086] Figure 6 shows the inside of the second sipe according to this disclosure.

[0087] As shown in Figure 6, the second sipe 328 may have a first projection 32 that begins at the bottom of the second sipe 328 and extends radially outward. The first projection 32 of the second sipe 328 may be located between the first portion 322 and the second portion 324 of the second block 320. That is, in some embodiments, the first projection 32 of the second sipe 328 may be located adjacent to the second groove 20 that extends substantially circumferentially through the block 320.

[0088] In some embodiments, the second sipe 328 may include a second projection 34 that begins at the bottom of the second sipe 328 and extends radially outward. The second projection 34 of the second sipe 328 may be located between the second portion 324 and the third portion 326 of the second block 320.

[0089] In some embodiments, the second sipe 328 may further comprise a third projection 36 of the second sipe 328, the third projection 36 of the second sipe 328 starting from the bottom of the second sipe 328 and extending radially outward. The third projection 36 of the second sipe 328 may be located in a third portion 336 of the second block 320. Preferably, in the tire according to the present invention, the second sipe may be located substantially in the axial direction of the third portion of the tire.

[0090] As described above, the second sipe 328 may preferably be located in a second block 320 of a second subset of the block, i.e., in a block having a pitch length smaller than the maximum pitch length.

[0091] If there are more than two pitch lengths, for example three or more, the third sipe 338 and further sipes may be placed in blocks with even smaller pitch lengths, such as the third block 330 of the third subset block 330 as described with reference to Figure 4. The third sipe 338 and further sipes may correspond to the second sipe 328 as described above.

[0092] By providing a third projection on the third portion 326 of the second block 320 or the third portion 336 of the third block 330, additional reinforcement of the block in the central portion becomes possible. Since this portion usually has a smaller width than the first and second block portions, especially with smaller pitch lengths, i.e., the second and third pitch lengths, reinforcement of this region by the third projection is particularly beneficial to the distribution of stiffness across the tread. Thus, this feature can improve the distribution of contact pressure across the entire contact patch, thereby resulting in good grip overall. Local reinforcement of the third portion of the block, i.e., the central portion, also improves the lateral road holding of the tire in particular.

[0093] As shown in Figures 5 and 6, at least one of the first projection of the first sipe, the second projection of the first sipe, the first projection of the second sipe, the second projection of the second sipe, or the third projection of the second sipe includes at least one curved portion 25. Preferably, at least one curved portion has a radius of at least 0.8 mm and at most 3.0 mm, preferably greater than 1.0 mm.

[0094] The curved sections allow for a more uniform distribution of stiffness because the curvature of the protrusions results in a gradual increase / decrease in stiffness along the extension of each protrusion. In this way, high stress concentrations at a single point on the tread can be avoided, leading to improved wear performance.

[0095] In some embodiments, at least one of the first projection of the first sipe, the second projection of the first sipe, the first projection of the second sipe, the second projection of the second sipe, or the third projection of the second sipe may have a maximum height of at least 20% and up to 80% of the depth of the respective sipe. The projection height is directly related to the increase in stiffness of each block portion. Having projections within the above range provides a good balance between local reinforcement and block / sipe deformation. Higher maximum heights increase reinforcement and therefore improve wear performance, while lower heights increase the bending capacity of the block and sipe, and increase traction on snow. The specified ranges provide an improved trade-off between the two effects.

[0096] In some embodiments, at least one of the first projection of the first sipe, the second projection of the first sipe, the first projection of the second sipe, the second projection of the second sipe, or the third projection of the second sipe may have an elongated shape along the extension of the sipe, preferably a polygonal shape, more preferably a quadrangular or triangular shape, and even more preferably a rectangular shape. The rectangular shape allows for an improved stiffness distribution because the rectangular projection extends further along the sipe. These provide a uniform height and therefore a uniform stiffness distribution, which is beneficial for the tire's wear performance.

[0097] In some embodiments, at least one edge of at least one of the first projection of the first sipe, the second projection of the first sipe, the first projection of the second sipe, the second projection of the second sipe, or the third projection of the second sipe may have a curved shape, preferably an arc or a spline shape. This avoids stress concentrations that may be introduced by tangent discontinuities that may be introduced by providing polygonal projections. This is also beneficial to the tire's wear performance.

[0098] Figure 7 shows an enlarged view of a block illustrating possible locations for the protrusions according to this disclosure.

[0099] If the block in Figure 6 corresponds to the first block 310 in Figure 4, then the sipe shown in Figure 6 may correspond to the first sipe 318. The sipe may then have a first projection 22 between the first portion 312 and the second portion 314 of the block 310. Furthermore, the sipe may have a second projection 24 between the second portion 314 and the third portion 316 of the block 310.

[0100] If the block in Figure 6 corresponds to the second block 320 or the third block 330 in Figure 4, the sipe shown in Figure 6 may correspond to the second sipe 328. The sipe may then have a first projection 32 between the first portion 322 and the second portion 324 of the block 320 or 330. Furthermore, the sipe may have a second projection 34 between the second portion 324 and the third portion 326 of the block 320 or 330. Furthermore, if the block in Figure 6 corresponds to the second block 320 or the third block 330 in Figure 4, the sipe shown in Figure 6 may further have a third projection 36 located on the third portion 326 of the block 320 or 330.

[0101] In some embodiments, at least one of the first sipe and the second sipe is -The innermost axial end closed by the block, -The outermost axial end is closed by a block, and may comprise at least one of the following:

[0102] This makes it possible to avoid localized stress discontinuities, especially across less rigid block sections. Such discontinuities can lead to excessive localized deformation, which can be avoided by providing the first sipe as defined above.

[0103] In some embodiments, the width of at least one of the first and second sipes may vary by at least 0% and up to 100% of the sipe width over the outermost 2 mm of the radial edge of each sipe, with the sipe width measured 2 mm below the outermost radial surface. Wider sipes on the tread surface can result in higher pressure on the sipe edges, which can lead to greater deformation and therefore reduced performance, particularly during dry braking, as well as greater wear. This can be avoided by providing the sipes defined above.

[0104] Figure 8 shows an exemplary embodiment of the V-shaped directional tread pattern according to the present disclosure.

[0105] As shown in Figure 8, some embodiments of the tread may include a second set of continuous blocks 50, which are positioned opposite the equatorial plane 16 of the tire and generally correspond to a first set of continuous blocks 10. In some embodiments, as shown in Figure 8, the second set of continuous blocks 50 can be axially symmetric with respect to the first set of blocks 10, resulting in a V-shaped tread pattern with a preferred rolling direction. The V-shape offers the advantage of improved drainage characteristics, as water can be drained from the contact patch by two opposing first grooves located in the axial directions of the tread on opposite sides when the tire rolls in the preferred rolling direction. This can improve traction on wet surfaces. While a directional pattern with a preferred rolling direction is advantageous on wet surfaces, other embodiments are also possible.

[0106] For example, Figure 9 shows an exemplary embodiment of an S-shaped tread pattern according to the present disclosure. In some embodiments, according to Figure 9, the tread may comprise a second set of continuous blocks 50 in addition to a first set of continuous blocks 10. The second set of continuous blocks 50 may be positioned on the opposite side of the tire's equatorial plane 16. In contrast to the embodiments described above, which include a V-shaped tread pattern, the second set of continuous blocks 50 may be point-symmetric with respect to the first set of blocks 10, resulting in an S-shaped tread pattern that does not have a preferred rolling direction.

[0107] Figure 10 shows a blade for forming a sipe according to this disclosure.

[0108] According to some aspects of the present invention, a mold for forming a tire can be provided. The mold may comprise a plurality of cavities for forming a set of continuous blocks 10 arranged along the outer circumference of a tire 100, the set of continuous blocks 10 comprising a first subset of blocks arranged according to a first pitch having a first pitch length. The mold may further comprise a plurality of projections for forming a plurality of first grooves arranged across the outer circumference of the tire, each of the plurality of first grooves positioned between two blocks of the set of continuous blocks. The mold may further comprise at least one blade 40 for forming a first sipe positioned in one of the blocks of the first subset, the blade comprising a first recess for forming a first projection of the first sipe.

[0109] Such a mold may be configured to form a tire according to any one of the embodiments described above. In particular, the recesses 42 of the blade 40 allow for the formation of protrusions in each portion of the sipes, and thus also have the advantage of providing a means for forming a tire with improved wear performance and improved traction, as described above.

[0110] In some embodiments, the blade 40 may further include a second recess 44 for forming a second projection of the first sipe. The first projection of the first sipe and the second projection of the second sipe may be positioned between the first block portion of a first subset of a continuous block of the set. The block portion may be defined as described above.

[0111] In some embodiments, the mold may further comprise a second set of cavities of a second subset of blocks arranged according to a second pitch having a second pitch length, wherein the second pitch length is smaller than the first pitch length, preferably 90% or less of the first pitch length.

[0112] The mold may then include a second blade 40 for forming a second sipe located in one of a second subsets of the block. The second blade may include a first recess 42 for forming a first projection of the second sipe. Preferably, the second blade may further include a second recess 44 for forming a second projection of the second sipe. More preferably, the second blade may further include a third recess 46 for forming a third projection of the second sipe.

[0113] The recesses 42, 44, and 46 of the blade 40 may each have at least one curved portion 45 having a radius of at least 0.8 mm and at most 3.0 mm, preferably greater than 1.0 mm. The curved portion 45 may be configured to form one of the curved portions 25 of the protrusions. At least one of the recesses 42, 44, and 46 may have a maximum height of at least 20% and at most 80% of the depth of the respective sipe.

[0114] According to some embodiments, at least one of the recesses 42, 44, and 46 may have an elongated shape along the extension of the sipe, preferably a polygonal shape, more preferably a quadrangular or triangular shape, and even more preferably a rectangular shape. At least one of the recesses 42, 44, and 46 may have a curved shape, preferably an arc or a spline shape.

[0115] In some embodiments, the blade 40 may have an axial innermost end 48 that can be surrounded by the block 10. The axial innermost end 48 of the blade 40 may be spaced apart from the axial innermost end of the cavity forming the block 10.

[0116] For example, the blade 40 shown in Figure 10 may further include a recess 49 which can be configured to form a sipe projection as shown in Figure 3G. In other embodiments, the blade may be formed in any one of the shapes described with reference to Figures 3A to 3G, for example, to form sipes of different shapes.

[0117] In some embodiments, the first projection of the second sipe and the second projection of the second sipe may be positioned between the block portions, as described in more detail above. Preferably, the third projection of the second sipe may be positioned in the center of the third portion of the second block, preferably the third portion.

[0118] Therefore, the mold according to this aspect of the present invention is configured to provide the tire defined above, having the same advantages and improvements.

[0119] Tire footprint measurement In the context of this disclosure, “tire footprint” means all parts of the tire that are in contact with the ground when the tire is inflated and under load. The tire footprint provides information about the behavior of the tread profile under normal conditions; that is, from the tire footprint, it is possible to know which parts of the blocks are in contact with the road surface under static load conditions.

[0120] When analyzing tire footprints, each tire is generally inflated to a pressure appropriate to its type. For standard passenger car radial tires with a nominal section width of 195 mm or less, a tire pressure of 1.9 bar is used. For standard passenger car radial tires with a nominal section width of 205 mm or more, a tire pressure of 2.0 bar is used. For reinforced passenger car radial tires of any size, a pressure of 2.3 bar is used. For tires used in commercial vans and trucks, the standardized inflation pressure set by the European Tire and Rim Technology Association (ETRTO) is used. All measurements are taken at room temperature.

[0121] Next, loads are applied to the tire under the following conditions: For passenger car radial tires, the tire is loaded with a weight equivalent to 88% of the tire load index according to the ETRTO chart. Tires for commercial vans and trucks are loaded with a weight corresponding to the ETRTO single load rating standard. To perform the measurements, ink may be applied to the tread profile, and then the tire may be pressed onto a card according to the above specifications, leaving an ink footprint that can then be analyzed. The footprint is evaluated for three tire sections placed at equal intervals of 120 degrees around the circumference of the tire. The metrics analyzed within the footprint are then averaged across the three measured sections.

[0122] Measurement of tire void volume and rubber volume In the context of this application, the tire void volume is also measured under footprint conditions. That is, the tire is inflated in the same manner as described above for tire footprint measurement. The void volume is measured for each pixel by a laser measurement system capable of detecting its relative depth to the tread surface. Thus, the total void volume within the contact patch can be calculated by integrating over all measured pixels. The total tread volume can be calculated as the product of the tire's footprint width (FW) and circumference (C) multiplied by the weighted average depth of the first groove. In this case, the total volume of rubber is the difference between the total tread volume and the total void volume.

[0123] The measurements given in this disclosure refer to measurements taken on new tires that have not been exposed to wear prior to measurement, under footprint conditions. [Explanation of symbols]

[0124] 10, 310, 320, 330 blocks 12 The first groove 14 sipes 16 Equatorial plane 20 The second groove 22, 32 First projection 24, 34 Second protrusion 36 Third protrusion 40 blades 42, 44, 46, 49 Blade recesses 100 tires 101, 312, 322, 332 Part 1 102, 314, 324, 334 Second part 103, 316, 326, 336 Third part 110 tread 120 circumferential direction 130 Axis 140 Radial 150 center 310 Block 1 318 First Sipe 320 Second block 328 Second Sipe 330 Third Block 338 The third sipe 340, 350 block recesses

Claims

1. A vehicle tire having a tread, wherein the tread is A set of continuous blocks arranged along the outer circumference of the tire, including a set of continuous blocks that includes a first subset of blocks arranged according to a first pitch having a first pitch length, A plurality of first grooves arranged over the outer circumference of the tire, each of the plurality of first grooves comprising a plurality of first grooves arranged between two blocks of the set of continuous blocks, Each first block of the first subset of the set of consecutive blocks is A vehicle tire comprising a first sipe arranged in the first block, the first sipe having a first projection of the first sipe that starts from the bottom of the first sipe and extends radially outward.

2. Each first block of the first subset of blocks comprises a first portion of the first block positioned in the shoulder region of the tire, and a second portion of the first block positioned axially inward of the first portion of the first block, The tire according to claim 1, wherein the first projection of the first sipe is positioned between the first portion of the first block and the second portion of the first block.

3. The tire according to claim 1 or 2, wherein the first sipe further includes a second projection of the first sipe that begins at the bottom of the first sipe and extends radially outward.

4. Each first block of the first subset of blocks further includes a third portion of the first block positioned axially inward of the second portion of the first block, The first sipe further comprises a second projection of the first sipe that begins at the bottom of the first sipe and extends radially outward, The tire according to claim 2, wherein the second projection of the first sipe is located between the second portion of the first block and the third portion of the first block.

5. The sequence of blocks in the aforementioned set, A second subset of blocks arranged according to a second pitch having a second pitch length, further comprising a second subset of blocks where the second pitch length is smaller than the first pitch length, Each second block of the second subset of the continuous blocks of the set is A tire according to any one of claims 1 to 4, comprising a second sipe arranged in the second block, the second sipe having a first projection of the second sipe and a second projection of the second sipe, wherein each of the first and second projections of the second sipe begins at the bottom of the second sipe and extends radially outward.

6. Each second block of the second subset of blocks comprises a first portion of the second block positioned in the shoulder region of the tire, a second portion of the second block positioned axially inward of the first portion, and a third portion of the second block positioned axially inward of the second portion of the second block. The first projection of the second sipe is positioned between the first portion of the second block and the second portion of the second block. The tire according to claim 5, wherein the second projection of the second sipe is positioned between the second portion of the second block and the third portion of the second block.

7. The tire according to claim 5 or 6, wherein the first pitch length is the maximum pitch length of the tire, and the second pitch length is 90% or less of the first pitch length.

8. The second sipe further includes a third projection of the second sipe, the third projection of the second sipe starting from the bottom of the second sipe and extending radially outward, The tire according to claim 6 or 7, wherein the third projection of the second sipe is positioned on the third portion of the second block.

9. The tire according to claim 8, wherein the third projection of the second sipe is located substantially at the axial center of the third portion.

10. The third portion of at least one of the first block or the second block has an axial extension of at least 25% and up to 40% of the half-footprint width of the tire, The second portion of at least one of the first block or the second block has an axial extension of at least 25% and up to 55% of the half-footprint width of the tire, The first portion of the first block or at least one of the second block has an axial extension of at least 20% and up to 35% of the half-footprint width of the tire. The tire according to claim 4 or 6.

11. The separation between at least two parts of at least one of the first block or the second block is One or more recesses on one or more edges of the block, Change in the inclination angle of the block with respect to the circumferential direction of the tire, The direction or magnitude of the curvature of the aforementioned block, Gradual increase or decrease in the width of the chamfered area. A groove extending substantially circumferentially through the aforementioned block, or A tire according to any one of claims 2, 4, 6, or 10, defined by any combination of these.

12. The tire according to any one of claims 1 to 11, wherein at least one of the first projection of the first sipe, the second projection of the first sipe, the first projection of the second sipe, the second projection of the second sipe, or the third projection of the second sipe has at least one curved portion.

13. The tire according to claim 12, wherein the at least one curved portion has a radius of at least 0.8 mm and at most 3.0 mm, preferably greater than 1.0 mm.

14. The tire according to any one of claims 1 to 13, wherein at least one of the first projection of the first sipe, the second projection of the first sipe, the first projection of the second sipe, the second projection of the second sipe, or the third projection of the second sipe has a maximum height of at least 20% and a maximum of 80% of the depth of each of the sipes.

15. The tire according to any one of claims 1 to 14, wherein at least one of the first projection of the first sipe, the second projection of the first sipe, the first projection of the second sipe, the second projection of the second sipe, or the third projection of the second sipe has an elongated shape along the extension of the sipe, preferably a polygonal shape, more preferably a quadrilateral or triangular shape, and even more preferably a rectangular shape.

16. The tire according to any one of claims 1 to 14, wherein at least one edge of at least one of the first projection of the first sipe, the second projection of the first sipe, the first projection of the second sipe, the second projection of the second sipe, or the third projection of the second sipe has a curved shape, preferably an arc or a spline shape.

17. At least one of the first sipe and the second sipe is The innermost axial end closed by the aforementioned block, A tire according to any one of claims 1 to 16, comprising at least one of the axial outermost end closed by the aforementioned block.

18. The tire according to any one of claims 1 to 17, wherein the width of at least one of the first sipe and the second sipe varies by at least 0% and up to 100% of the sipe width over the outermost radial 2 mm of each sipe, and the sipe width is measured at a position 2 mm below the outermost radial surface.

19. A mold for forming a tire, wherein the mold comprises a plurality of cavities for forming a set of continuous blocks arranged along the outer circumference of the tire, and the set of continuous blocks comprises a first subset of blocks arranged according to a first pitch having a first pitch length. The aforementioned mold, - A plurality of projections for forming a plurality of first grooves arranged along the outer circumference of the tire, each of the plurality of first grooves comprising a plurality of projections positioned between two blocks of the set of continuous blocks, - Further comprising at least one blade for forming a first sipe located in one of the blocks of the first subset, - A mold in which the blade has a first recess for forming a first projection of the first sipe.

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