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, each of which includes a first portion located on the shoulder portion of the tire and a second portion axially positioned toward the equatorial plane of the tire relative to the first portion, and comprises a plurality of first grooves arranged along the outer circumference of the tire, each of which is located between two blocks of the set of continuous blocks, a plurality of second grooves arranged along the outer circumference of the tire, each of which is located between the first and second portions of each block of the set, and at least one recess located in at least one of the first and second portions of each block, the recess being located adjacent to the second groove.

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] Some known tires have grooves that extend substantially circumferentially within the block between two consecutive grooves that extend substantially axially. These grooves are located between the shoulder portion of the block and the inward portion, sometimes called the intermediate or central portion. The shoulder portion of the block, for example in a V-shaped or S-shaped tread, is generally positioned perpendicular to the direction of rolling and is primarily intended to provide acceleration and braking performance, and consequently to provide frictional forces parallel to the direction of driving, such as braking or acceleration forces. Therefore, braking and acceleration result in deformation of the block, particularly in the shoulder portion. Grooves are provided between the shoulder portion and the portion inward from the axial direction (sometimes called the intermediate portion) to still ensure steering performance and prevent contact loss between the rubber and the ground.

[0005] However, such grooves have the disadvantage of locally increasing the wear energy of the tire due to the additional edges. This results in higher overall wear and uneven wear of the tread profile, as wear occurs mainly around the second groove.

[0006] Therefore, the object of the present invention is to provide a tire that reduces these drawbacks, has lower overall wear, and in which the wear is more uniformly distributed across the entire width of the tread, while having equivalent braking and acceleration performance. [Overview of the project]

[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, each of which includes a first portion located on the shoulder portion of the tire and a second portion axially positioned toward the equatorial plane of the tire relative to the first portion, and comprises a plurality of first grooves arranged along the outer circumference of the tire, each of which is located between two blocks of the set of continuous blocks, a plurality of second grooves arranged along the outer circumference of the tire, each of which is located between the first and second portions of each block of the set, and at least one recess located in at least one of the first and second portions of each block, the recess being located adjacent to the second groove.

[0009] Such tires have locally reduced block rigidity, which contributes to the separation of different parts of the blocks. This makes it possible to provide narrower grooves than in the absence of recesses, thereby reducing wear energy without losing the separation effect. Thus, tire wear can be reduced by providing a narrower second groove, but braking and steering performance are not significantly lost due to the reduction in groove width, as at least one additional recess (hereinafter also referred to as a “recess,” considering that a typical tread pattern has two or more of these recesses) adjacent to the second groove is provided. In fact, the reduction in groove width is beneficial for braking performance because the tread surface in contact with the ground is larger, and the parts of the blocks located closer to the shoulders benefit from increased rigidity. In this case, the recesses allow for good separation between the shoulder parts of the blocks and the more axially inward parts.

[0010] Furthermore, the recesses provide additional edging to the tire blocks, which improves performance on snow-covered ground.

[0011] In addition to reducing wear, the narrower grooves also improve drainage. Water guided outward from the tire's contact patch through substantially axially extending grooves (also referred to herein as "first grooves") may be disrupted by the turbulent flow generated around the edges of the second grooves. The narrower second grooves generate less turbulent flow, which improves drainage, avoids hydroplaning, and thus improves the overall performance of the tire on wet road surfaces.

[0012] Such tires can further increase the contact patch of the tire, thereby improving the static friction of the tire on wet ground, dry ground, and snow-covered ground. Specifically, this is achieved by providing recesses that improve the bending ability of the tire. By locally reducing the rigidity of the block by providing the recess, the block portions around the recess can be configured to behave as hinges, enabling the tire to bend at the desired position, and as a result, the tire generally shaped convexly can conform to a substantially flat ground. Furthermore, the improvement in bending further results in a more uniform distribution of the contact pressure across the entire contact patch, which provides a more uniform distribution of wear energy.

Brief Description of the Drawings

[0013] [Figure 1] It is a schematic view of a vehicle tire according to the present disclosure. [Figure 2] It shows a semi-tread profile of a tire according to the present disclosure. [Figure 3A] It shows an enlarged view of the shoulder portion of a block according to the present disclosure. [Figure 3B] It shows an enlarged view of the second groove and the recess adjacent thereto. [Figure 4A] It shows some exemplary embodiments of the arrangement of the recesses according to the present disclosure. [Figure 4B] It shows some exemplary embodiments of the arrangement of the recesses according to the present disclosure. [Figure 4C] It shows some exemplary embodiments of the arrangement of the recesses according to the present disclosure. [Figure 4D]Several exemplary embodiments of the arrangement of recesses according to this disclosure are shown. [Figure 5] This disclosure illustrates exemplary embodiments of the V-shaped directional tread pattern. [Figure 6] This disclosure illustrates exemplary embodiments of the S-shaped tread pattern. [Figure 7] Two graphs are shown illustrating the measurement results of wear energy at different tire widths. [Modes for carrying out the invention]

[0014] To overcome the shortcomings of the prior art described above, the present invention aims to provide a groove (also referred to herein as the "second groove") that separates the shoulder portion from the intermediate portion, which is narrower than grooves known from the prior art, as the local wear energy near the groove increases with the groove width. Therefore, the narrower the groove, the greater the reduction in wear energy. However, a narrow groove also hinders the purpose of mechanically separating the shoulder portion from the rest of the block to reduce the deformation effect that occurs on the rest of the block during braking, for example. That is, if the groove is very narrow, the shoulder portion and the intermediate portion of the block may come into contact inside the tire contact patch, resulting in a loss of the desired separation of the two portions. In other words, a very narrow groove reduces local wear energy, but due to the loss of separation effect, it may also reduce braking performance, as well as steering performance, especially during braking / acceleration.

[0015] To harmonize both objectives, the present invention discloses a tire comprising at least one recess located in at least one of the first and second portions of each block, wherein the recess is located adjacent to a second groove. Such a recess is configured to locally reduce the rigidity of the block and thus contribute to the separation of the different portions of the block. This makes it possible to provide a narrower groove than in the absence of a recess, thereby reducing wear energy without losing the separation effect. Thus, tire wear can be reduced by providing a narrower second groove, but braking and steering performance are not significantly lost due to the reduction in groove width, as the recess is additionally located adjacent to the second groove.

[0016] In addition to reducing wear, narrower grooves also improve drainage. Water guided outward from the tire's contact patch through substantially axial grooves (also referred to herein as “first grooves”) may be disturbed by turbulence generated around the edges of second grooves. Narrower second grooves generate less turbulence, which improves drainage, prevents hydroplaning, and therefore improves the overall performance of the tire on wet surfaces.

[0017] This recess further improves the tire's bending ability. By locally reducing the block's rigidity through the recess, the block portion around the recess can be configured to behave as a hinge, allowing the tire to bend at a desired position. As a result, a generally convex-shaped tire can adapt to substantially flat ground. Therefore, the improved bending ability of the recess can increase the tire's contact patch, thereby improving tire traction on wet, dry, and snow-covered ground.

[0018] In the preferred embodiments described in detail below, further improvement of traction on snow-covered ground is achieved by providing additional sipes, which are small cuts in the blocks and typically, but not necessarily, substantially axially extending. Such sipes are configured to trap snow within them and provide an additional edge to improve performance on snow-covered surfaces. Providing multiple sipes to further improve snow performance reduces the stiffness of the blocks and thus impairs dry and wet performance; therefore, to achieve an acceptable trade-off between snow performance and wet / dry performance, preferably only a few sipes per block, most preferably only one sipe per block, are provided on the tire.

[0019] 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.

[0020] "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.

[0021] Figure 1 is a schematic diagram of a vehicle tire according to this disclosure.

[0022] According to Figure 1, the tire 100 includes a tread 110. The tread comprises a set of continuous blocks 10 and a plurality of grooves 18, each groove 18 being positioned between two blocks 10 of the set of continuous blocks. Furthermore, sipes 30 may be positioned within each of the set of continuous blocks 10.

[0023] The blocks may be arranged continuously in the circumferential direction 120 of the tire.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] Furthermore, any numerical angle given herein should be considered an absolute value, that is, not limited to the direction of each angle.

[0029] Figure 2 shows a half-tread profile of a tire according to the present disclosure. According to Figure 2, the tire tread comprises a set of continuous blocks 10 arranged along the outer circumference of the tire. In the context of the present 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. The present invention according to the present disclosure is preferably provided for all blocks of a tire, but some blocks that may be located between the individual blocks 10 of the set of continuous blocks may not have a second groove or recess.

[0030] Each of the set of continuous blocks 10 comprises a first portion 12 positioned on the shoulder portion of the tire and a second portion 14 positioned axially toward the equatorial plane 16 of the tire relative to the first portion. In some embodiments described in more detail elsewhere in this specification, the tread comprises further blocks on the other side of the equatorial plane 16 of the tire. In some embodiments described elsewhere in this specification, these further 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 further 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 18 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 18 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 18 are generally defined by adjacent blocks 10.

[0034] The primary purpose of the grooves 18 is to guide water along the grooves 18 toward the tire's shoulder as the tire rolls on the ground, thereby draining water from the contact patch. Thus, the grooves 18 improve tire performance, especially in wet road conditions. 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 the wear effect that causes wear.

[0035] As shown in Figure 2, the tread further has a plurality of second grooves 20, each of which is located between the first portion 12 and the second portion 14 of each block 10 of the set. In some embodiments, each second groove 20 is arranged substantially circumferentially. In some embodiments, each second groove 20 may be arranged as substantially straight lines slightly inclined with respect to the circumferential direction, for example, and in other embodiments, as shown in Figure 2, for example, each second groove 20 may be arranged in a zigzag shape including, for example, three different inclined portions. The zigzag configuration of the second grooves 20 allows for partial interruption of the tire's deformation and sliding behavior, and thus improves the distribution of wear energy across the entire axial extension of the block 10.

[0036] The second groove generally serves to separate the first portion 12 of the block 10 from the second portion 14 of the block 10. For example, during acceleration or braking, the first portion of the block 10 may be particularly prone 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 first portion 12. Therefore, it is desirable to mechanically separate the first portion 12 of the block 10 from the second portion 14 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 20 between them. In this way, the second portion 14 still provides lateral road holding and steering performance despite the deformation of the first portion 12. A wider second groove improves the separation effect compared to a narrower second groove.

[0037] However, providing the second groove 20 leads to an increase in localized wear energy due to the additional edge provided on the block. This localized wear energy increases as the second groove 20 widens. Therefore, in order to reduce wear energy, it is desirable to make the second groove 20 as narrow as possible, but as explained, narrowing the second groove 20 worsens the separation effect. In the most extreme case, where there is no second groove 20 at all, there is no increase in wear energy as desired, but there is also no mechanical separation, which is undesirable. Therefore, some trade-off must be made between tire wear and the mechanical separation of the first part 12 and the second part 14.

[0038] This trade-off can be mitigated by providing at least one recess 22 located in at least one of the first portion 12 and the second portion 14 of each block 10, the recess 22 being located adjacent to the second groove 20. The recess 22 locally reduces the circumferential extension of the block 10, and as a result, the rigidity of the block 10 is also reduced at the location of the recess 22. Consequently, the recess 22 contributes to mechanically separating the first portion 12 from the second portion 14 without significantly contributing to locally increased wear energy. Therefore, when the recess 22 is provided, the second groove 20 can be made narrower, and thus localized wear energy can be reduced without losing the benefit of mechanical separation between the first portion 12 and the second portion 14.

[0039] The arrangement of the recesses 22 is preferably such that the second grooves 20 transition into the recesses 22. In other words, in this configuration, each second groove 20 and each recess 22 form a continuous gap. Therefore, both the recesses 22 and the second grooves 20 can transition together into the first groove 18, and thus form a continuous gap together with the first groove 18.

[0040] While the described technical effect is achieved by providing a single recess, it should be understood that further improvements can be brought about, depending on the tread design, by providing two or more recesses arranged in a single block. For example, as shown in the figure, the first recess 22 may be located in the second portion 14 of the block, and the second recess, for example, recess 24, may be located in the first portion 12 of the block. The first and second recesses are also located adjacent to the second groove 20, and thus further enlarge the gap formed compared to a configuration in which only a single recess 22 is applied. Furthermore, a configuration in which two recesses are provided per block can be applied to each block 10 of a set of continuous blocks. Alternatively, some of the blocks 10 may have only one recess (for example, in the second portion of the block), while other blocks 10 may have two or more recesses (for example, the first recess in the second portion of the block and the second recess in the first portion of the block).

[0041] In some embodiments, the width of each of the multiple second grooves 20 may be substantially narrower than the width of each of the multiple first grooves 18. When comparing the widths of the first grooves 18 and the second grooves 20, the average width of the second grooves 20 and the width of the first grooves 18 at positions adjacent to the second grooves 20 are taken into consideration.

[0042] Preferably, the ratio between the average width of the second groove 20 and the width of the first groove 18 measured at a position adjacent to the second groove may be at least 0.1 and at most 0.7. Preferably, the ratio between the width of the second groove 20 and the width of the first groove 18 may be at least 0.13 and at most 0.45.

[0043] This allows for a good trade-off between low wear energy and good mechanical separation of the first part 12 and the second part 14.

[0044] In some embodiments, the width of each of the multiple second grooves may be at least 1 mm and at most 2.5 mm. Preferably, the width of the second groove may be at least 1.2 mm and at most 2.2 mm.

[0045] In some embodiments, each block may have a front edge and a rear edge. One or more recesses 22 may be further disposed on at least one of the front edge and rear edge of at least one of the first and second portions of each block. Thus, various configurations for arranging one or more recesses are possible. For example, the recesses 22 may be disposed on both the front edge and the rear edge of the first portion of each block, or on both the front edge and the rear edge of the second portion of each block, or on the front edge of one of the first or second portions of each block and the rear edge of one of the first or second portions of each block.

[0046] 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's contact patch with the ground.

[0047] 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.

[0048] As outlined above, by providing two recesses, the effect of recess 22 is further enhanced, that is, the circumferential extension of block 10 is locally reduced, and as a result, the rigidity of block 10 is also reduced between the first recess 22 and the second recess 24. As a result, recesses 22 and 24 contribute to the mechanical separation of the first portion 12 from the second portion 14 without significantly contributing to locally increased wear energy.

[0049] As shown in Figure 2, the tread may further comprise a plurality of sipes 30. In the illustrated tread pattern, each of the plurality of sipes 30 may preferably extend substantially along the shape of at least one of the first portion 12 and second portion 14 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 block. 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 from 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.

[0050] The 30 sipes can trap snow within them, providing an additional edge to the tread. This improves traction on snow-covered ground.

[0051] In some embodiments, the multiple sipes 30 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,

[0052]

number

[0053] 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.

[0054] 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 stiffness, which generally deteriorates braking / acceleration performance on dry ground. When the edge component is within either of the above ranges, the balance between traction on snow-covered ground and braking / acceleration performance on dry ground is particularly good.

[0055] Preferably, the edge component is balanced with the provision of recesses and the second groove(s). For example, since the recesses locally reduce the stiffness, the edge component should remain within the indicated range to ensure sufficient stiffness. Also, since the recesses contribute to snow capture, fewer sipes, or sipes of shorter length, may be required. When two or more recesses are provided per block, and / or when one or more recesses have a larger surface, it may be beneficial to provide an edge component within the range of at least 2 and up to 10 at the bottom.

[0056] 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 of the void volume V V to the rubber volume V R 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 / VRThis is directly related to the stiffness of the tread profile. Therefore, the ratio V V / V R A higher V ratio indicates a greater amount of void space in the tread, which improves braking performance by reducing the tread's rigidity. 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.

[0057] Figure 3 shows an enlarged view of the first portion 12 of block 10 as described herein.

[0058] The configuration shown in Figure 3A generally corresponds to the embodiment shown in Figure 2, and the block comprises a first portion 12 and a second portion 14, a second groove 20, a first recess 22, and a second recess 24.

[0059] According to Figure 3A, the first recess 22 has a first recess area A1, the second recess 24 has a second recess area A2, and the second groove 20 has a groove area A groove It has. Also, the first part 12 has an area A shoulder It has the area A of the first portion 12 near the outer edge in Figure 3. shoulder The contact patch is defined by the outer edge of the tire's contact patch. Measurement of the contact patch width is described elsewhere in this specification.

[0060] In some embodiments, the block 10 may further comprise one or more chamfers on at least one of its leading and trailing edges. In the context of this disclosure, “chamfer” means an inclined side wall of the 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 end of the inclined wall. The chamfer height (= distance between the outer block surface and the radially innermost end 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.

[0061] If block 10 has a chamfered portion relating to the first part 12, area A shoulder To determine this, the area of ​​the chamfered portion is considered to belong to the area of ​​the first portion 12. Therefore, area A shoulder To determine this, the chamfered portion is ignored; that is, the radial innermost edge of the chamfered portion is projected onto the outermost tread surface, and the projected edge is considered to define the circumferential boundary of the shoulder region.

[0062] In some embodiments, (i) the sum of the area of ​​the first recess A1 and the area of ​​the second recess A2, A1+A2, and (ii) the groove area A groove The ratio (A1+A2) / A groove It is at least 0.3 and at most 1.4. Preferably, the ratio is (A1 + A2) / A groove It may be at least 0.4 and at most 1.1.

[0063] In some embodiments, (i) the area A of the second groove 20 groove (ii) Area A of the first part 12 shoulder Ratio A groove / A shoulder This may be at least 0.020 and at most 0.100. Preferably, ratio A groove / Ashoulder It may be at least 0.02 and at most 0.07.

[0064] In some embodiments, (i) the sum of the area of ​​the first recess A1 and the area of ​​the second recess A2, A1+A2, and (ii) the area of ​​the first portion 12 A shoulder The ratio (A1+A2) / A shoulder This may be at least 0.010 and at most 0.120. Preferably, the ratio is (A1 + A2) / A shoulder This may be at least 0.012 and at most 0.080.

[0065] As further shown in Figure 3, the first recess 22 has an outer edge 222, which is the edge of the recess closest to the shoulder portion of the tire, and an inner edge 224 opposite the outer edge. The outer edge 222 is inclined at an angle α with respect to the circumferential direction, i.e., with respect to a plane parallel to the equatorial plane of the tire, and the inner edge is inclined at an angle β with respect to the circumferential direction. In some embodiments, α is at least 0 degrees and at most 35 degrees. Preferably, α is at least 0 degrees and at most 25 degrees. Within this range of inclination angles, the outer edge 222 provides an additional edge of the tread to further improve lateral grip, particularly on snow-covered ground.

[0066] In some embodiments, the ratio (β-α) / α of the inclination angles α and β of the outer edge 222 and inner edge 224 of the first recess 22 is at least 0.35 and at most 0.45. Preferably, the ratio (β-α) / α is at least 0.37 and at most 0.43. This relationship of the inclination angles between the outer edge 222 and the inner edge 224 can improve the ability of the recess to catch snow and further improve the snow performance of the tire.

[0067] The embodiments described above have been explained with respect to the first recess 22 for simplicity. However, alternatively, these embodiments are applicable to the outer edge 242 and inner edge 244 of the second recess 24, and it will be understood that, preferably, certain angles and angle ratios are applicable to both the first recess 22 and the second recess 24.

[0068] In some embodiments, the first recess 22 and / or the second recess 24 may be located at the end of the second groove 20 such that the groove 20 opens into the first recess 22 and / or the second recess 24, as shown in Figure 3. Furthermore, as also shown in Figure 3, in some embodiments, the outer edge 222 of the first recess 22 and / or the outer edge 242 of the second recess 24 may be adjacent to the first portion 12.

[0069] In some embodiments, one edge of the first recess 22 and / or the second recess 24 may be positioned in continuity with one side wall of the second groove 20. This configuration avoids additional protrusions that would cause turbulence in the water guided by the first groove. Thus, this embodiment further improves drainage and, therefore, enhances tire traction on wet road surfaces.

[0070] According to Figure 3B, at least one recess has a recess extension C measured in the circumferential direction. Therefore, to measure the extension C, the recess is projected onto a plane parallel to the equatorial plane 16 of the tire. The recess extension C corresponds to the maximum extension of the recess in this protrusion.

[0071] Furthermore, as shown in Figure 3B, each of the multiple second grooves has an extension A measured in the circumferential direction. Therefore, in order to measure the extension A of the second groove 20, the center point of the foremost circumferential edge and the center point of the rearmost circumferential edge of the second groove are projected onto a plane parallel to the equatorial plane 16 of the tire, and the extension A corresponds to the distance between these projected points.

[0072] In some embodiments, the ratio C / A of the recess extension C to the extension A of the second groove may be at least 0.02 and at most 0.2. Preferably, the ratio C / A may be at least 0.05 and at most 0.18.

[0073] As described above, in some embodiments, the tread may include a second recess 24. According to such embodiments, the second recess 24 may have a circumferentially measured extension D, such that each of the first recess 22 and the second recess 24 may have a circumferentially measured recess extension C. In some embodiments, the ratio of (i) the sum of the recess extensions of the first recess 22 and the second recess 24 to (ii) the extension of the second groove 20 may be expressed as (C+D) / A. This ratio (C+D) / A may be at least 0.1 and at most 0.3. Preferably, the ratio (C+D) / A may be at least 0.15 and at most 0.25. Ratios in these ranges provide a particularly good trade-off between low wear energy and good mechanical separation of the first portion 12 and the second portion 14.

[0074] In some embodiments, the recess extensions C and D may be equal. In some embodiments, the recess widths C and D may be different.

[0075] According to Figure 3B, the first portion extends circumferentially adjacent to the second groove 20 and / or recesses 22, 24, and this is indicated by extension B. Extension B of the first portion 12 can be measured by projecting the innermost axial edge of the first portion adjacent to the outermost axial wall of the second groove 20 onto a plane parallel to the equatorial plane 16 of the tire, and then measuring the circumferential extension of this projected edge. In some embodiments, the ratio A / B of the extension A of the second groove 20 to the extension B of the first portion 12 may be at least 0.7 and at most 0.9. Preferably, the ratio A / B is at least 0.73 and at most 0.87.

[0076] According to some embodiments, the first recess 22 and / or the second recess 24 may have a radially measured depth equal to at least 30% of the depth of at least one of the first groove 18 and the second groove 20, preferably equal to the depth of at least one of the first groove 18 and the second groove 20. These depths improve the bending and separation effect of the recesses, thus enabling improved tire traction and reduced wear.

[0077] According to some embodiments, the maximum width E, F measured between the two opposing edges of the first recess 22 and / or the second recess 24 may be at least 2.5 mm and at most 6.5 mm. Preferably, the maximum width E, F measured between the two opposing edges of the first recess 22 and / or the second recess 24 may be at least 3 mm and at most 6 mm.

[0078] According to some embodiments, the first recess 22 and / or the second recess 24 may have a circumferentially measured height of at least 1.5 mm and a maximum of 4.5 mm. Preferably, the first recess 22 and / or the second recess 24 may have a circumferentially measured height of at least 1.6 mm and a maximum of 4 mm.

[0079] Figures 4A to 4D show different possible arrangements of the two recesses 22 and 24 adjacent to the second groove 20 that separates the first portion 12 from the second portion 14.

[0080] In some embodiments, as shown in Figure 4A, for example, both the first recess 22 and the second recess 24 are positioned axially inward from the second groove 20. This embodiment provides improved braking performance because the recesses 22 and 24 are generally located within the second portion 14. Thus, the area of ​​the first portion 12 is increased compared to other possible configurations, and as a result, the braking performance of the tire can be improved.

[0081] In another embodiment, as shown in Figure 4B, the first recess 22 and the second recess 24 are both positioned axially outward from the second groove 20. This arrangement of recesses increases the bending flexibility of the shoulder of the block 10 and thus reduces the strain and stress resulting from the tire being pressed toward the ground.

[0082] In yet another embodiment, as shown in Figure 4C, the first recess 22 is positioned axially outward from the second groove 20, and the second recess 24 is positioned axially inward from the second groove 20. This arrangement of recesses allows for a more uniform distribution of voids across the first portion 12 and the second portion 14, holding more rubber material at the trailing edge of the first portion, which experiences greater stress during longitudinal maneuvers such as dry braking and acceleration. This improves braking / acceleration performance.

[0083] In yet another embodiment, as shown in Figure 4D, the first recess 22 is positioned axially inward from the second groove 20, and the second recess 24 is positioned axially outward from the second groove 20. This arrangement of recesses also allows for a more uniform distribution of voids across the first portion 12 and the second portion 14. In this configuration, more rubber material is retained at the leading edge of the first portion, thereby improving traction on snow-covered ground.

[0084] Figure 5 shows an exemplary embodiment of the V-shaped directional tread pattern according to this disclosure.

[0085] As shown in Figure 5, 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 5, 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.

[0086] For example, Figure 6 shows a tread pattern according to the present disclosure that does not have a preferred rolling direction. In some embodiments, according to Figure 6, 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 provided point-symmetrically with respect to the first set of blocks 10, resulting in an S-shaped tread pattern that does not have a preferred rolling direction.

[0087] Figure 7 shows two graphs illustrating the measurement results of wear energy in different axial regions of the tire. Both graphs show the wear energy in joules / cubic meter (J / m³) for four regions of the tread profile, which can correspond to the first portion 12 and the second portion 14 on either side of the tire's equatorial plane. 3The wear energy is indicated in units of ). The bar labeled "LS" corresponds to the first portion 12 on the left side of the tire's equatorial plane. The bar labeled "LIR" corresponds to the second portion 14 on the left side of the tire's equatorial plane. The bar labeled "RIR" corresponds to the second portion 14 on the right side of the tire's equatorial plane. The bar labeled "RS" corresponds to the first portion 12 on the right side of the tire's equatorial plane.

[0088] The upper graph, shown with respect to Figure 5, shows the measurement results of the V-shaped pattern described above, but with a "wide" second groove, i.e., the present invention is not applied. The lower graph shows the measurement results of the V-shaped pattern with the present invention applied, i.e., with a narrower second groove 20 and recesses 22 and 24 applied. The tires in both measurements have comparable total surface voids, and the difference in performance can be attributed to the improved distribution of voids across the tire according to the present invention.

[0089] As can be seen from the graph, when the present invention is applied, the wear energy is lower for each of the analyzed tire sections than when the tire has wide grooves but no recesses. Furthermore, it has been shown that the difference in wear between individual sections is reduced by providing narrow grooves and adjacent recesses, which ultimately leads to more uniform tire wear during the service cycle and thus reduces the non-uniformity caused by uneven wear of the tread profile. Tire footprint measurement

[0090] 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.

[0091] 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.

[0092] 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. Measurement of tire void volume and rubber volume

[0093] 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.

[0094] 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]

[0095] 10, 50 blocks 12 Part 1 14. Part 2 16 Equatorial plane 18 The first trench 20 The second groove 22, 24 recesses 30 sipes 100 tires 110 tread 120 circumferential direction 130 Axis 140 Radial 150 center 222, 242 Outer edge 224, 244 inner edge

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, wherein each of the set of continuous blocks includes a first portion positioned on the shoulder portion of the tire and a second portion positioned axially toward the equatorial plane of the tire relative to the first portion, A plurality of first grooves arranged along the outer circumference of the tire, each of the plurality of first grooves being arranged between two blocks of the set of continuous blocks, A plurality of second grooves, each of which is positioned between the first and second portions of each of the blocks of the set, A vehicle tire comprising at least one recess located in at least one of the first and second portions of each block, the at least one recess located adjacent to the second groove.

2. The tire according to claim 1, wherein the width of each of the plurality of second grooves is substantially narrower than the width of each of the plurality of first grooves.

3. The tire according to claim 1 or 2, wherein the width of each of the plurality of second grooves is at least 1 mm and at most 2.5 mm.

4. The tire according to any one of claims 1 to 3, wherein each block has a front edge and a rear edge, and the at least one recess is further disposed on at least one of the front edge and the rear edge of at least one of the first and second portions of each block.

5. The at least one recess has a recess extension measured in the circumferential direction, Each of the plurality of second grooves has an extension measured in the circumferential direction, The ratio of the recess extension to the extension of the second groove is at least 0.02 and at most 0.

2. A tire according to any one of claims 1 to 4.

6. The tire according to any one of claims 1 to 4, wherein the at least one recess includes a first recess and a second recess, and each of the first recess and the second recess is arranged adjacent to the second groove.

7. The tire according to claim 6, wherein the first recess is located at least one of the leading edge of the first portion and the leading edge of the second portion, and the second recess is located at least one of the trailing edge of the first portion and the trailing edge of the second portion.

8. Each of the first recess and the second recess has a recess extension measured in the circumferential direction, Each of the plurality of second grooves has an extension measured in the circumferential direction, (i) The ratio of the sum of the recess extensions of the first recess and the second recess to (ii) the extension of the second groove is at least 0.1 and at most 0.

3. The tire according to claim 6.

9. The first recess has a first recess area, the second recess has a second recess area, each of the plurality of second grooves has a second groove area, and under the following conditions, (a) (i) The ratio of the sum of the area of ​​the first recess and the area of ​​the second recess to the area of ​​the second groove is at least 0.3 and at most 1.

4. (b) (i) the ratio of the area of ​​the second groove to (ii) the area of ​​the first portion is at least 0.020 and at most 0.100, and (c) At least one of the following applies: (i) the ratio of the sum of the area of ​​the first recess and the area of ​​the second recess to (ii) the area of ​​the first portion is at least 0.010 and at most 0.

120. A tire according to any one of claims 6 to 8.

10. The aforementioned tread, A plurality of sipes, each of which extends substantially along the shape of at least one of the first and second portions of each of the continuous blocks of the set, The plurality of sipes determine an edge component EI corresponding to the ratio of the sum of the axial protrusion lengths of the plurality of sipes to the outer circumference C of the tread, thereby, [Math 1] The tire according to any one of claims 1 to 9, wherein the EI is at least 2 and at most 20.

11. The tire according to any one of claims 1 to 10, wherein the ratio of the void volume to the rubber volume is at least 0.20 and at most 0.

40.

12. The at least one recess has an outer edge which is the edge of the recess closest to the shoulder portion of the tread, and an inner edge opposite the outer edge, wherein the outer edge is inclined at an angle α with respect to the circumferential direction, and the inner edge is inclined at an angle β with respect to the circumferential direction, and the following conditions apply: (a) α is at least 0 degrees and at most 35 degrees, (b) The tire according to any one of claims 1 to 11, wherein at least one of the following is applied: the ratio (β-α) / α is at least 0.35 and at most 0.

45.

13. The at least one recess is, A depth equal to at least 30% of the depth of at least one of the first groove and the second groove, preferably a depth equal to the depth of at least one of the first groove and the second groove. The maximum width measured between the two opposing edges of the at least one recess, which is at least 2.5 mm and a maximum of 6.5 mm, and A tire according to any one of claims 1 to 12, having at least one of a circumferential height of at least 1.5 mm and a maximum of 4.5 mm.

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