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 comprises a set of continuous blocks arranged along the outer circumference of the tire, and a plurality of first grooves arranged across the outer circumference of the tire, each of the plurality of first grooves positioned between two of the set of continuous blocks. Each of the set of continuous blocks comprises a second groove extending through the block. The second groove connects two consecutive first grooves and is positioned to separate the block in the tire footprint into a shoulder section and a second section, a leading edge section and a trailing edge section. Each of the set of continuous blocks further comprises a first chamfered portion positioned on the leading edge of the block, and a second chamfered portion positioned on the trailing edge of the block. The tire in a rolling state has a gap surface-to-rubber surface ratio of at least 0.30 and at most 0.50.

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 or off-road tires. [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] For tires intended for use in a variety of ground conditions, such as wet, dry, and snow-covered surfaces, there are several design parameters that must be optimized to provide good performance across all ground conditions. In some cases, optimizing design parameters for one type of road condition may result in some performance loss in other situations. Therefore, improvements to various design parameters are needed, with the goal of achieving synergistic effects.

[0005] Therefore, the object of the present invention is to provide a tire that has improved performance on all types of road surfaces, such as wet roads, dry roads, and snow-covered roads. [Overview of the project]

[0006] This objective is achieved by providing an improved vehicle tire as described in the independent claim. Further embodiments are described in the dependent claims.

[0007] According to an aspect of the present invention, a vehicle tire having a tread is provided. The tread comprises a set of continuous blocks arranged along the outer circumference of the tire, and a plurality of first grooves arranged across the outer circumference of the tire, each of the plurality of first grooves positioned between two of the set of continuous blocks. Each of the set of continuous blocks comprises a second groove extending through the block. The second groove connects two consecutive first grooves and is positioned to separate the block in the tire footprint into a shoulder section and a second section, a leading edge section and a trailing edge section. Each of the set of continuous blocks further comprises a first chamfered portion positioned on the leading edge of the block, and a second chamfered portion positioned on the trailing edge of the block. The tire in a rolling state has a gap surface-to-rubber surface ratio of at least 0.30 and at most 0.50.

[0008] Such tires offer improved characteristics compared to all-season tires, particularly on snow-covered ground. Generally, to increase traction on snow-covered ground, it is necessary to reduce the surface area of ​​the blocks and increase the contact pressure between the block surface and the ground. This contact pressure can be improved by setting the ratio of the air gap surface to the rubber surface to at least 0.30 and a maximum of 0.50, thereby improving grip performance, especially on snow-covered ground. However, in order to ensure that the blocks, especially the edges of the blocks, bite into the snow and enhance the tire's grip, the blocks also require appropriate stiffness. Stiffness is highly dependent on the width of the blocks, and reducing the width of the blocks to increase the air gap surface and contact pressure is typically equivalent to reducing stiffness. In other words, reducing the block width while leaving all other parameters (e.g., block shape, block height, inclination angle, edge component, etc.) intact generally results in a loss of stiffness. Therefore, if the desired surface air gap is obtained by reducing the block width (rather than by applying chamfering), this leads to a loss of stiffness that impairs the overall performance of the tire.

[0009] To mitigate the effects of increased surface voids, the Disclosure provides a first chamfer and a second chamfer. The chamfer reduces the surface area of ​​the block (to increase contact pressure) without reducing the actual width of the block which is relevant to determining the block's stiffness. Since the chamfer is provided only near the surface of the block, it only reduces the surface area without reducing the width of the block. Thus, the effect of reducing the surface area (to increase contact pressure) is mitigated by keeping the width of the block high in all parts that are relevant to generating stiffness. In other words, the Disclosure makes it possible to maintain the stiffness of the block despite its reduced rubber volume without having to change to a material compound with stiffer properties. This is particularly beneficial for snow performance because stiffer material compounds typically exhibit lower snow friction capabilities, and as a result, the use of such stiffer compounds leads to a loss of overall snow traction.

[0010] By providing blocks with higher rigidity, braking performance on dry ground is also improved, and by providing chamfered sections, the chamfered sections can compensate for the loss of contact area during braking due to block deformation, which is even more beneficial. Therefore, the tire according to this disclosure provides improved traction on snow and improved braking performance on dry ground. [Brief explanation of the drawing]

[0011] [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 3] Figure 2 shows the individual blocks of the set of consecutive blocks. [Figure 4A] Figure 3 shows three cross-sections of different parts of the block. [Figure 4B] Figure 3 shows three cross-sections of different parts of the block. [Figure 4C] Figure 3 shows three cross-sections of different parts of the block. [Figure 5] This disclosure shows the tire footprint. [Figure 6] This disclosure illustrates exemplary embodiments of the V-shaped directional tread pattern. [Figure 7] This disclosure illustrates exemplary embodiments of the S-shaped tread pattern. Detailed explanation

[0012] Generally, to improve snow performance, it is desirable that the ratio of void surface to rubber surface be at least 0.30 and at most 0.50. A higher ratio indicates a larger amount of void surface and therefore a smaller amount of rubber surface, and consequently, a higher ratio corresponds to higher contact pressure and therefore better snow performance.

[0013] However, in order to achieve a ratio within a desired range, generally, it is necessary to reduce the extension of the tread block, for example, by increasing the width of the first groove. Such a reduction in the size of the tread block decreases the rigidity of the block, thereby facilitating the deformation of the block on any ground, and then degrades the performance of the tire. However, especially on snow-covered ground, the deformation suppresses the block from sufficiently biting into the snow, and can provide desired traction on the snow-covered ground. Further, large deformation may result in a reduction in the contact area, which further reduces the overall grip due to lower friction. Therefore, according to the present disclosure, the extension of the block remains at a desired width, and the surface area is reduced by the chamfer. In this way, the block maintains its width along most of the radial extension of the block, including the width of all parts essentially related to determining its stability. Thus, in short, the block can maintain its stability while still reducing the surface area by the chamfer.

[0014] In the context of the present disclosure, the "chamfer" means the inclined sidewall of the block that extends radially inward from the outer block surface. The wall is inclined such that the width of the block measured in the circumferential direction increases towards the bottom of the groove. Each chamfer is defined by a height and a width. The chamfer height may correspond to the distance measured radially between the outer block surface and the radially innermost end of the inclined wall. The height of the chamfer (= the distance between the outer block surface and the radially innermost end of the inclined wall) is usually lower than the total height of the block, and may be, for example, at most 50% or less of the total height of the block. The width of the chamfer may be measured perpendicular to the block and corresponds to the width of the inclined chamfer wall when it protrudes on the outer tread surface.

[0015] The chamfer portion at the trailing edge further contributes to dry braking performance. When the vehicle brakes, due to the inertia of the vehicle's mass, the tread blocks deform and bend. In this way, a part of the rubber surface disposed near the leading edge of the block loses the contact state with the road surface, thus reducing the contact surface of each block. When the contact surface is reduced, the frictional force is reduced, and accordingly, the braking performance of the tire is impaired.

[0016] By providing a chamfer portion at the trailing edge, the inclined surface of the chamfer portion is pushed toward the ground during braking when the block bends, thus increasing the rubber surface. In this way, the surface loss at the tip of the block can be compensated, the contact surface is increased, and thereby, good braking performance can be obtained due to the increase in frictional force. Therefore, the chamfer portion at the trailing edge of the block contributes to dry and wet braking performance.

[0017] On the other hand, the chamfer portion at the leading edge has been proven to function efficiently to contribute to traction, especially on a ground covered with snow. Generally, in order to increase the traction on a ground covered with snow, it is necessary to reduce the surface area of the block to increase the contact pressure between the block surface and the ground. Providing a chamfer portion at the leading edge has been shown to be a good position for reducing the surface area of the block surface. The increase in contact pressure provided by the chamfer portion at the leading edge, which brings a peak in contact pressure especially at the leading edge of the block, enables the block, especially its leading edge, to bite into the snow more efficiently, and thus increases the traction of the tire on a ground covered with snow.

[0018] Figure 1 is a schematic view of a vehicle tire according to the present disclosure.

[0019] According to Figure 11, the tire 100 includes a tread 110. The tread has a set of continuous blocks 10 and grooves 12 disposed between two of the blocks 10 of the set of continuous blocks. Further, sipes 14 may be disposed in each of the set of continuous blocks 10.

[0020] The blocks may be arranged continuously in the circumferential direction 120 of the tire.

[0021] 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.

[0022] "Sipes" also refer to cuts in the tread pattern. In this specification, "sipes" refer to cuts within a block, rather than "grooves" separating 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, but this is not always necessary. For example, a depth of at least 1 mm, preferably at least 20% of the depth of the first groove, is conceivable.

[0023] 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 11, the circumferential direction 120 is therefore a direction that lies in a plane parallel to the yz plane.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] Furthermore, any numerical angle given herein should be considered an absolute value, that is, not limited to the direction of each angle.

[0028] Figure 2 shows the half-tread profile of the tire according to this disclosure.

[0029] As shown in Figure 2, the 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 the tire, some blocks that may be located between the individual blocks 10 of the set of continuous blocks may not have the chamfered portion according to the present invention.

[0030] 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, and the overall pattern is 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] As shown in Figure 2, each block of the set of continuous blocks comprises a second groove 18 positioned between the shoulder section 17 and a second section 19 of the block. The second section 19 may be axially positioned toward the equatorial plane 16 of the tire relative to the shoulder section 17. In some embodiments, each second groove 18 is positioned substantially circumferentially. In some embodiments, each second groove 18 may be positioned, 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 18 may be positioned in a zigzag shape including, for example, three different inclined sections. Such a zigzag configuration of the second groove 18 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.

[0036] The second groove 18 is intended to separate the block within the tire footprint into the shoulder section 17 and the second section 19. Therefore, the second groove may be positioned so that the shoulder section 17 and the second section 19 do not come into contact with each other in the tire footprint.

[0037] Therefore, the second groove 18 generally serves to mechanically separate the shoulder section 17 of the block 10 from the second section 19. For example, during acceleration or braking, the shoulder section 17 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 section 17. Therefore, it is desirable to mechanically separate the shoulder section 17 from the second section 19 in order to ensure good steering performance and lateral road holding during braking and acceleration. This separation is preferably achieved by providing a second groove 18 between them. In this way, the second section 19 still provides lateral road holding and steering performance despite the deformation of the shoulder section 17. A wider second groove improves the separation effect compared to a narrower second groove.

[0038] Figure 5 shows an exemplary tire footprint 500 illustrating the second groove, the shoulder section 17, and their mechanical separation effect with respect to the second section 19. The ratio of the depth of the second groove 18 to the depth of the first groove 12 may be at least 0.30. This further enhances the mechanical separation of the shoulder section 17 and the second section 19 of the block 10. The depth of the first groove(s) 12 may also be called the “non-slip depth” (NSD), and may be, for example, at least 6 mm and a maximum of 12 mm, preferably at least 7 mm and a maximum of 10 mm.

[0039] 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 preferably extend substantially along the shape of each of the set of continuous blocks 10. However, other arrangements and shapes of sipes on the outer tread surface are also possible, such as corrugated, zigzag, etc. Sipes do not necessarily have to follow the shape of the blocks. For example, sipes may be included only along a portion of the shape of the block, or may have a different angle of inclination with respect to the circumferential direction than the block or portion of the block below. Also, some sipes may have walls that extend radially toward the center of the tire, while some sipes may have corrugated, zigzag, etc., shapes 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.

[0040] The 14 sipes can trap snow within them, providing an additional edge to the tread. This improves traction on snow-covered ground.

[0041] 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,

[0042]

number

[0043] 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.

[0044] 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 braking / acceleration performance on dry ground. When the edge component is within the above range, the balance between traction on snow-covered ground and braking / acceleration performance on dry ground is particularly good.

[0045] The edge component is directly related to the rigidity of the block. Therefore, depending on the geometric shape of the tread pattern, especially when applying chamfers, an appropriate edge component should be selected to maximize the snow digging ability and avoid extensive deformation of the block that offsets the advantages introduced by the chamfers. The above range provides such a beneficial trade-off between snow digging ability and block rigidity.

[0046] 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 0.40. 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 ratio V V / V RA higher V ratio indicates a greater amount of void space in the tread, which is beneficial for snow performance by increasing the contact pressure between the blocks and the ground. V / V R A lower void-to-rubber ratio indicates a greater amount of rubber in the tread, which improves braking performance by increasing rigidity. A specific range of void-to-rubber ratios provides an optimal trade-off between snow performance and dry performance, resulting in a tire that exhibits good braking performance on dry ground as well as good traction on snow-covered ground.

[0047] The tire in Figure 2 has a ratio of air gap surface to rubber surface of at least 0.30 and a maximum of 0.50. Preferably, the ratio of air gap surface to rubber surface is At least 0.30 and at most 0.35, At least 0.36 and at most 0.39, At least 0.40 and at most 0.45, and It may be at least one of 0.46 and 0.50.

[0048] A ratio of at least 0.30 and a maximum of 0.35 provides improved dry braking performance due to a larger amount of rubber surface area in contact with the ground.

[0049] A ratio of at least 0.36 and a maximum of 0.39 provides a good trade-off between dry braking performance and snow traction, as it slightly reduces the rubber surface area, thus increasing snow traction while maintaining relatively good braking performance.

[0050] A ratio of at least 0.40 and a maximum of 0.45 also provides a good trade-off between dry braking performance and snow traction as the rubber surface area decreases further, thus further increasing snow traction while still maintaining relatively good braking performance.

[0051] A ratio of at least 0.46 and up to 0.50 provides improved snow traction because it results in less rubber surface area in contact with the ground, and consequently higher contact pressure.

[0052] Figure 3 shows the individual blocks of the sequence of blocks in Figure 2.

[0053] According to Figure 3, each block 10 includes a leading edge portion 20 and a trailing edge portion 30.

[0054] 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.

[0055] 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.

[0056] The leading edge portion 20 may comprise a first portion 22 located in the shoulder region of the tire, a second portion 24 located axially inward of the first portion 22, and a third portion 26 located axially inward of the second portion 24. The trailing edge portion 30 may comprise a first portion 32 located in the shoulder region of the tire, a second portion 34 located axially inward of the first portion 32, and a third portion 36 located axially inward of the second portion 34.

[0057] The first portions 22, 32 of the leading edge 20 and the trailing edge 30 may be referred to as the "shoulder portion," the second portions 24, 34 of the leading edge 20 and the trailing edge 30 may be referred to as the "intermediate portion," and the third portions 26, 36 of the leading edge 20 and the trailing edge 30 may be referred to as the "central portion." The central portion may be positioned adjacent to the equatorial plane 16 of the tire.

[0058] As shown in Figure 3, the axial extensions of corresponding edges may differ between edges; that is, as shown in Figure 3, the second portion 34 of the rear edge 30 may have a larger axial extension than the corresponding second portion 24 of the front edge 20. Generally, the third portions 26, 36 of the front edge 20 and the rear edge 30 may have axial extensions of at least 25% and up to 40% of the half-footprint width of the tire. Thus, the third portions 26, 36 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.

[0059] The second portions 24, 34 of the leading edge 20 and trailing edge 30 may have axial extensions of at least 25% and up to 55% of the half-footprint width of the tire. Thus, the second portions 24, 34 preferably begin from the axially outer ends of the third portions 26, 36 and extend axially outward to a width of 65% to 80% of the half-footprint width of the tire.

[0060] The first portions 22, 32 of the leading edge 20 and trailing edge 30 may have axial extensions of at least 20% and up to 35% of the half-footprint width of the tire. Thus, the first portions 22, 32 preferably begin at the axial outer ends of the second portions 24, 34 and extend axially outward to the axial outer ends of the tire, i.e., cover the entire half-footprint width axially outward from the second portions 24, 34.

[0061] In some embodiments, the separation between the two parts, the leading edge and the trailing edge, Recesses at the edges of adjacent parts, Changes in the inclination angle of each edge of the tire with respect to the circumferential direction, The direction or magnitude of the curvature of each edge, Gradual increase or decrease in the width of the chamfered area. A groove extending substantially circumferentially through the block, or It may be defined by any of these combinations.

[0062] For example, as shown in Figure 3, the recess 222 can separate the second portion 24 of the leading edge 20 from the third portion 26 of the leading edge 20. Furthermore, the recess 224 can separate the first portion 22 of the leading edge 20 from the second portion 24 of the leading edge 20. Similarly, the recess 322 can separate the second portion 34 of the trailing edge 30 from the third portion 36 of the trailing edge, and the recess 324 can separate the first portion 32 of the trailing edge 30 from the second portion 34 of the trailing edge 30.

[0063] Alternatively, other means of separation between the edges are also possible. For example, as shown in Figure 3, a second groove 18 extending substantially circumferentially through the block 10 may separate the first portions 22, 32 from the second portions 24, 34. Although such a groove is shown only in Figure 3 to separate the first portions 22, 32 from the second portions 24, 34, a similar groove may be located between the second portions 24, 34 and the third portions 26, 36.

[0064] Furthermore, although only the recesses 222, 224, 322, 324 and the second groove 18 are shown in Figure 3 as means for separating adjacent edge portions, other means such as gradually increasing or decreasing the chamfer width can be used.

[0065] 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.

[0066] Furthermore, the angle of inclination of each block relative to the circumferential direction of the tire can be used to determine the separation between edges.

[0067] According to one approach, the angle of inclination of each portion of the edge is determined by the angle between (i) the tangent applied to each edge of the block and (ii) the circumferential direction of the tire. If each portion of the edge has a chamfer, the tangent is applied to the outermost circumferential end of the block (neglecting the width and shape of the chamfer). This approach can be used when each portion of the edge is formed continuously or substantially continuously, i.e., without substantial circumferential cuts in between, and there is a discontinuity in the inclination of each edge with respect to the circumferential direction of the tire, for example, a significant change. In this case, the discontinuity corresponds to a separation between adjacent edge portions.

[0068] Preferably, the inclination angle of the first portions 22, 32 (i.e., the inclination angle of the tangent on each portion of the edge 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 portions 24, 34 may be at least 50 degrees and a maximum of 65 degrees with respect to the circumferential direction. Preferably, the inclination angle of the second portions 24, 34 may be at least 50 degrees and a maximum of 60 degrees with respect to the circumferential direction. The inclination angle of the third portions 26, 36 may be at least 20 degrees and a maximum of 50 degrees with respect to the circumferential direction. Preferably, the inclination angle of the third portions 26, 36 may be at least 30 degrees and a maximum of 50 degrees with respect to the circumferential direction.

[0069] According to another approach that may be used when each edge does not exhibit discontinuity in the inclination of the tire with respect to the circumferential direction, the separation between edge portions is preferably determined according to an axial extension of the footprint width as described above in relation to Figure 3, a recess in each edge, the direction or magnitude of the curvature of each edge, a gradual increase or decrease in the chamfer width, or a groove that extends substantially circumferentially through the block.

[0070] 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 26, 36, 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 24, 34, which begin at the axial outer 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 22, 32, 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.

[0071] Furthermore, various combinations of means for separating the edge portions are also possible. For example, Figure 3 shows a combination of recesses 224, 324 and a second groove 18 for separating the first portions 22, 32 and the second portions 24, 34, and there are other possible combinations.

[0072] According to Figure 3, block 10 further comprises a first chamfered portion 25 located on the front edge 20 of block 10 and a second chamfered portion 35 located on the rear edge 30 of block 10.

[0073] The first chamfered portion 25 may be located on at least one of the first portion 22, the second portion 24, and the third portion 26 of the leading edge portion 20, and the second chamfered portion 35 may be located on at least one of the first portion 32, the second portion 34, and the third portion 36 of the trailing edge portion 30. Preferably, the first chamfered portion 25 may be located on the first portion 22 of the leading edge portion 20, and the second chamfered portion 35 may be located on the first portion 32 of the trailing edge portion 30.

[0074] By providing chamfered edges on the first portions 22 and 32, and particularly on the first portion 32 of the trailing edge 30, braking performance on dry ground is improved, as will be described in more detail elsewhere in this specification.

[0075] In some embodiments, the first chamfer 25 may be located on at least two of the first portion 22, second portion 24, and third portion 26 of the front edge 20, and the second chamfer 35 may be located on at least two of the first portion 32, second portion 34, and third portion 36 of the rear edge 30. Preferably, the first chamfer may be located on the first portion 22, second portion 24, and third portion 26 of the front edge 20, and the second chamfer 35 may be located on the first portion 32, second portion 34, and third portion 36 of the rear edge 30.

[0076] By providing chamfered portions 25 and 35 not only on the first portions 22 and 32 but also on portions beyond that, the contact pressure can be further increased by reducing the surface area, and therefore, snow traction and dry braking performance are improved.

[0077] In some embodiments, each block of the set of blocks 10 may further comprise a third groove extending substantially circumferentially through the block. The third groove may be positioned to interrupt the leading edge 20 of the block 10 between the second portion 24 and the third portion 26, or the trailing edge 30 of the block 10 between the second portion 34 and the third portion 36. By providing the third groove, the block surface 40 can be further reduced, and thus the traction of the tire on snow can be further improved. Furthermore, the third groove provides an additional edge that can bite into the snow, thus increasing traction on snow-covered ground. In addition, the additional gap can improve drainage.

[0078] In some embodiments, the ratio of the depth of the third groove to the depth of the first groove is at least 0.30. This further enhances the mechanical separation of the block components, and therefore improves braking and steering performance.

[0079] Figure 3 further shows the three cutting lines CS1, CS2, and CS3. Figures 4A to 4C show three cross-sections of different parts of the block in Figure 3.

[0080] As shown in Figures 4A to 4C, the block 10 may have chamfered portions of different widths in different parts, thereby reducing the surface area of ​​the block 40 by the chamfered portions, while the width of the block may remain larger in the radially inward portion from the chamfered portions, so that the rigidity of the block is not impaired by the reduction in surface area.

[0081] Figure 4A shows a cross-sectional view of block 10 cut along line CS1. Thus, Figure 4A shows the first chamfer 25 in the first portion 22 of the front edge 20 of block 10 and the second chamfer 35 located in the first portion 32 of the rear edge 30 of block 10. As described above, the chamfer width is measured perpendicular to the block tangent. Figure 4A shows the width 212 of the first chamfer 25 in the first portion 22 of the front edge 20 and the width 312 of the second chamfer 35 in the first portion 32 of the rear edge 30.

[0082] Figure 4B shows a cross-sectional view of block 10 cut along line CS2. Thus, Figure 4B shows the first chamfer 25 in the second portion 24 of the front edge 20 of block 10 and the second chamfer 35 located in the second portion 34 of the rear edge 30 of block 10. Figure 4B shows the width 214 of the first chamfer 25 in the second portion 24 of the front edge 20 and the width 314 of the second chamfer 35 in the second portion 34 of the rear edge 30.

[0083] Figure 4C shows a cross-sectional view of block 10 cut along line CS3. Thus, Figure 4C shows the first chamfer 25 in the third portion 26 of the front edge 20 of block 10 and the second chamfer 35 located within the third portion 36 of the rear edge 30 of block 10. Figure 4C shows the width 216 of the first chamfer 25 in the third portion 26 of the front edge 20 and the width 316 of the second chamfer 35 in the second portion 34 of the rear edge 30.

[0084] The widths of the first chamfered portion 25 and the second chamfered portion 35 may vary within a particular section. For example, the first chamfered portion 25 may have a first width at a first position within the first portion 22 of the leading edge 20, and a second width different from the first width at a second position within the first portion 22 of the leading edge 20. The same applies to the second chamfered portion 35.

[0085] The embodiments described above concern blocks having three parts, but blocks having more parts, such as four or more parts, are also possible. This can be achieved, for example, by subdivision, i.e., by dividing a part into one or more continuously formed subparts.

[0086] Figure 5 shows the tire footprint according to this disclosure.

[0087] According to Figure 5, the tire footprint 500 is the footprint length L measured in the circumferential direction. FP The footprint may have a central footprint region that occupies 50% of the footprint length. The central footprint region can be obtained by measuring the tire footprint 500 as described below. From the tire footprint 500 thus measured, both footprint lengths L FP The upper 540 and bottom 520, which have a circumferential extension of 25%, are cut off as shown in Figure 5, resulting in a footprint length L centered between the uppermost end 560 and the lowermost end 580 of the tire footprint 500. FPThe central footprint, which accounts for 50% of the total footprint, remains.

[0088] In some embodiments, the average width of the second groove in the central footprint region may be at least 0.8 mm and a maximum of 5.0 mm, preferably at least 0.8 mm and a maximum of 2.5 mm. A wider second groove results in a larger surface gap, which in turn increases contact pressure and improves traction on snow. Furthermore, the second groove can provide mechanical separation between the shoulder section 17 and the second section 19 of the block 10, thereby enabling improvements in braking and acceleration performance, as well as overall road handling. However, a wider groove also increases localized wear energy in the immediate vicinity of the groove, while a narrower groove results in better wear performance. The above range provides an excellent balance between improved snow traction, braking, and handling, and good wear performance.

[0089] Figure 6 shows an exemplary embodiment of the V-shaped directional tread pattern according to the present disclosure.

[0090] As shown in Figure 6, 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 6, 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 directional patterns with a preferred rolling direction are advantageous on wet surfaces, other embodiments are also possible.

[0091] For example, Figure 7 shows an exemplary embodiment of an S-shaped tread pattern according to the present disclosure. In some embodiments, according to Figure 7, 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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 volume of the tread and the total volume of the voids.

[0096] 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]

[0097] 10, 50 blocks 12 The first groove 14 sipes 16 Equatorial plane 17 Shoulder division 18. The second trench 19. Second Section 20 Front edge 22, 32 Part 1 24, 34 Part 2 25 First chamfered section 26, 36 Third part 30 Trailing edge 35 Second chamfered section 40 Block surface 100 tires 110 tread 120 circumferential direction 130 Axis 140 Radial 150 center 212, 214, 216, 312, 314, 316 Chamfer width 222, 224, 322, 324 recesses 500 tire footprint 520 bottom 540 Top 560 Top end 580 Bottom end

Claims

1. A vehicle tire having a tread, wherein the tread is A set of continuous blocks arranged along the outer circumference of the aforementioned tire, 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 of the consecutive blocks in the aforementioned set is A second groove extending through the block, arranged to connect two consecutive first grooves, and arranged to separate the block within the tire footprint into a shoulder section and a second section, The leading edge and the trailing edge, A first chamfered portion is provided on the front edge of the block, The block comprises a second chamfered portion located on the rear edge of the block, A vehicle tire having a ratio of air gap surface to rubber surface of at least 0.30 and a maximum of 0.50 when the tire is in a rolling state.

2. The ratio between the void surface and the rubber surface is, At least 0.30 and at most 0.35, At least 0.36 and at most 0.39, At least 0.40 and at most 0.45, and The tire according to claim 1, wherein the coefficient of gravity is at least one of 0.46 and 0.

50.

3. The tire according to claim 1 or 2, wherein the tire footprint has a footprint length measured in the circumferential direction, the footprint has a central footprint region that accounts for 50% of the footprint length, and the average width of the second groove in the central footprint region is at least 0.8 mm and at most 5.0 mm, preferably at least 0.8 mm and at most 2.5 mm.

4. The aforementioned tread, The tread further comprises a plurality of sipes, each sipe determining an edge component EI corresponding to the ratio of the sum of the axial protrusion lengths of the plurality of sipes (SAP) to the outer circumference C of the tread, [Math 1] The tire according to any one of claims 1 to 3, wherein the EI is at least 2 and at most 20.

5. Each front edge and rear edge comprises a first portion located in the shoulder region of the tire, a second portion located axially inward of the first portion, and a third portion located axially inward of the second portion. The tire according to any one of claims 1 to 4, wherein the first chamfered portion is located on at least one of the first, second, and third portions of the leading edge, and the second chamfered portion is located on at least one of the first, second, and third portions of the trailing edge.

6. The tire according to claim 5, wherein the first chamfered portion is located on the first portion of the front edge, and the second chamfered portion is located on the first portion of the rear edge.

7. The tire according to claim 5 or 6, wherein the first chamfered portion is located on at least two of the first, second, and third portions of the leading edge, and the second chamfered portion is located on at least two of the first, second, and third portions of the trailing edge.

8. The tire according to any one of claims 5 to 7, wherein the first chamfered portion is arranged on the first, second, and third portions of the front edge, and the second chamfered portion is arranged on the first, second, and third portions of the rear edge.

9. The third portion of the front edge or the rear edge has an axial extension of at least 25% and up to 40% of the half-footprint width of the tire, The second portion of the front edge or the rear edge has an axial extension of at least 25% and up to 55% of the half-footprint width of the tire, The tire according to any one of claims 5 to 8, wherein the first portion of the leading edge or the trailing edge has an axial extension of at least 20% and up to 35% of the half-footprint width of the tire.

10. The separation between the two portions, the leading edge and the trailing edge, Recesses at the edges of adjacent parts, The change in the inclination angle of each edge of the tire with respect to the circumferential direction, The direction or magnitude of the curvature of each of the aforementioned edges, 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 5 to 9, defined by any combination of these.

11. The tire according to any one of claims 1 to 10, wherein the second groove is arranged to mechanically separate the shoulder section from the second section.

12. The tire according to any one of claims 5 to 10, wherein a third groove extends substantially circumferentially through each block, and the third groove is positioned to interrupt the leading edge of the block between the second and third portions, or the trailing edge of the block between the second and third portions.

13. The tire according to claim 12, wherein the ratio of the depth of the third groove to the depth of the first groove is at least 0.

30.

14. The tire according to any one of claims 1 to 13, wherein the ratio of the depth of the second groove to the depth of the first groove is at least 0.

30.

15. The tire according to any one of claims 1 to 14, wherein the tread has a ratio of void volume to rubber volume of at least 0.20 and at most 0.40.

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