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, each block having a leading edge and a trailing edge, and the tread comprises a plurality of first grooves arranged along the outer circumference of the tire, each of the plurality of first grooves being positioned between two of the set of continuous blocks. Each of the set of continuous blocks comprises a first portion positioned in the central part of the tire and a second portion positioned axially toward the shoulder of the tire relative to the first portion, the first portion and the second portion being formed in a continuous manner, and a first recess being formed between the first portion and the second portion, the first recess being positioned on at least one of the leading edge and the trailing edge of the block.

Description

[Technical Field]

[0001] This invention relates to vehicle tires. One possible application of the disclosed tire relates to an all-season tire that has come to be fitted to passenger cars or commercial vans. The invention 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 equatorial plane of the tire, toward the shoulder of the tire (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 movement of the vehicle through acceleration, braking, and / or steering.

[0004] Some known tires feature 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 inner 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 handling performance and prevent loss of contact between the rubber and the ground.

[0005] Therefore, to further improve bending ability, it might be conceivable to add additional grooves, for example, between the intermediate and central sections. However, such grooves have the disadvantage of locally increasing the wear energy of the tire due to the additional edges. This leads to higher total wear and uneven wear of the tread profile, as wear occurs mainly around these grooves.

[0006] Therefore, the object of the present invention is to mitigate these drawbacks and provide a tire that has equivalent performance but with less total wear and wear that is more evenly distributed across the entire width of the tread. [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 comprises a set of continuous blocks arranged along the outer circumference of the tire, each block having a leading edge and a trailing edge, and the tread comprises a plurality of first grooves arranged along the outer circumference of the tire, each of the plurality of first grooves being positioned between two of the set of continuous blocks. Each of the set of continuous blocks comprises a first portion positioned in the central part of the tire and a second portion positioned axially toward the shoulder of the tire relative to the first portion, the first portion and the second portion being formed in a continuous manner, and a first recess being formed between the first portion and the second portion, the first recess being positioned on at least one of the leading edge and the trailing edge of the block.

[0009] The continuous formation of the first and second sections, combined with the placement of recesses between these sections that function similarly to tread hinges, enables high tread bending capability. At the same time, the advantages of connecting the first and second sections, particularly the reduction of wear energy and the maintenance of higher longitudinal stiffness, are maintained. Furthermore, the recesses (or multiple recesses, if there are multiple recesses) also contribute to snow retention, thus increasing the grip of the snow tire. [Brief explanation of the drawing]

[0010] [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] This shows a magnified view of the block portion, including the recess. [Figure 4A] Various embodiments of a block having two recesses between a first part and a second part in different arrangements are shown. [Figure 4B] Various embodiments of a block having two recesses between a first part and a second part in different arrangements are shown. [Figure 4C] Various embodiments of a block having two recesses between a first part and a second part in different arrangements are shown. [Figure 4D] Shows various embodiments of a block having two recesses between a first portion and a second portion in different arrangements. [Figure 4E] Shows various embodiments of a block having two recesses between a first portion and a second portion in different arrangements. [Figure 5] Shows an exemplary embodiment of a V-shaped directional tread pattern according to the present disclosure. [Figure 6] Shows an exemplary embodiment of an S-shaped tread pattern according to the present disclosure. Detailed Description

[0011] In order to overcome the drawbacks of the prior art as described above, it may be desirable to provide a first recess at the leading edge or trailing edge of the block to locally reduce the rigidity of the block at the position of the recess. Thereby, when the tire is subjected to stress and / or strain, the recess with reduced rigidity can act as a hinge, enabling the tread to bend around the recess. In this way, a tire generally formed in a convex shape can be adapted to a substantially flat ground. Therefore, the improved bending ability of the recess (or recesses if there are multiple recesses) can improve the traction of the tire on wet ground, dry ground, and ground covered with snow by increasing the contact patch of the tire.

[0012] Furthermore, the recess provides an additional edge to the tire, which can further improve the performance of the tire on ground covered with snow. Also, the recess can trap snow inside and further improve traction on a snow-covered road.

[0013] By providing one or more recesses between the first (e.g., central) portion and the second (e.g., intermediate) portion of the tread, it becomes possible to omit the groove between the two portions. Thereby, as described above, it is possible to avoid the inconvenience associated with providing an additional groove between the central portion and the intermediate portion, that is, locally increasing the wear energy of the tread. Further, with the proposed solution, it is possible to more evenly distribute the wear energy across the width of the tread and avoid local peaks in wear.

[0014] Furthermore, grooves disposed substantially perpendicular to the first groove may generally cause turbulence in the water guided out through the first groove. By providing recesses instead of grooves, the risk of generating these turbulences can be reduced, and as a result, the drainage capacity of the tread is improved, thereby increasing the traction of the tire on a wet ground.

[0015] As a result, the recesses provide bending and separation of adjacent tread portions while reducing the adverse effects of grooves such as excessive wear energy and water turbulence.

[0016] In a preferred embodiment described in detail below, a further improvement in traction on snow-covered ground is obtained by additionally providing sipes, which are small cuts provided in the blocks and typically, although not necessarily, extend substantially axially. Such sipes are configured to capture snow therein and provide additional edges for improving performance on a snow-covered road surface. Providing a plurality of sipes for further improving snow performance reduces the rigidity of the block and thus impairs dry and wet performance. Therefore, in order to achieve an acceptable trade-off between snow performance and wet / dry performance, preferably a small number of sipes per block, most preferably only one sip per block, are provided in the tire.

[0017] 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, and 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.

[0018] The term "sipe" also refers to an indentation in the tread pattern. In this specification, "sipe" refers to an indentation within a block, rather than a "groove" 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, and 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 sometimes a sipe may extend to the entire depth of the tread block, 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.

[0019] Figure 1 is a schematic diagram of a vehicle tire according to this disclosure.

[0020] According to Figure 1, the tire 100 comprises a tread 110. The tread has 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.

[0021] The blocks may be arranged continuously in the circumferential direction 120 of the tire.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] Furthermore, any numerical angle given herein should be considered an absolute value, that is, not limited to the direction of each angle.

[0027] Figure 2 shows the half-tread profile of the tire according to this disclosure.

[0028] As shown in Figure 2, the tire tread has 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 invention according to this disclosure is preferably provided for all blocks of a tire, some blocks that may be arranged between the individual blocks 10 of the set of continuous blocks may not include any recess between the first (e.g., central) portion and the intermediate (e.g., second) portion of the block.

[0029] According to Figure 2, each block 10 comprises a first portion 12 positioned in the central part of the tire. The central portion of the tire is the portion closest to or adjacent to the equatorial plane 16 of the tire. Furthermore, according to Figure 2, each block 10 has a second portion 14 positioned axially toward the shoulder of the tire and immediately adjacent to the central portion relative to the first portion 12. The second portion 14 may be referred to as the “intermediate portion”. The first portion 12 may be referred to as the “central portion”. According to Figure 2, the first portion 12 and the second portion 14 are formed in a continuous manner, meaning there is no complete separation between the two portions 12, 14. Instead, they are formed as a single continuous arrangement.

[0030] Therefore, under normal rolling conditions, the first portion 12 and the second portion 14 should be at least partially in contact within the tire footprint. Thus, in order to form the two portions continuously, small notches may be provided to separate the two portions, insofar as the portions 12 and 14 are at least partially in contact within the tire footprint. Similarly, one or more sipes provided within the block (as described earlier) do not interfere with the continuous arrangement of the first portion 12 and the second portion 14.

[0031] As further shown in Figure 2, the first recess 22 is formed between the first portion 12 and the second portion 14. In the illustrated example, the first recess 22 is located on the front edge of the block 10. However, it may be located on the rear edge instead, or recesses may be provided on both edges between the first and second portions (see also below).

[0032] 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.

[0033] 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.

[0034] The first recess 22 may be positioned such that the stiffness of the block 10 is reduced in the region around the first recess 22 compared to the stiffness of the first portion 12 and the second portion 14. In this way, each of the continuous blocks 10 in the set is configured to bend around the first recess 22 when the tire is rolling.

[0035] Therefore, the first recess can provide a hinge-like function and improve the block's bending ability. By locally reducing the block's rigidity by providing the recess, the block portion around the recess can be configured to behave as a hinge, allowing the tire to bend between the first portion 12 and the second portion 14, and as a result, the generally convex-shaped tire can adapt to substantially flat ground. Thus, the improved bending ability of the first recess 22 increases the tire's contact patch, which enables improved tire traction on wet and dry ground as well as snow-covered ground.

[0036] Furthermore, the first recess 22 allows for a reduction in the mechanical connection between the first portion 12 and the second portion 14. In this way, the first portion 12 and the second portion 14 can respond independently to the stresses and strains applied to the block during the normal rolling state of the tire. Such strains and stresses are applied to the tire, for example, during braking, acceleration, or steering, and during overall rolling.

[0037] Tires known from the prior art achieve separation of the first section 12 and the second section 14 by providing additional grooves that are substantially arranged circumferentially. However, the circumferential grooves provide additional edges that locally increase the wear energy of the tread. This results in increased wear and an uneven distribution of wear energy, and as a result, the wear is unevenly distributed across the width of the tread, i.e., the block portions near the circumferential grooves experience more wear than other parts of the block.

[0038] By providing a recess 22 between the first portion 12 and the second portion 14, further grooves can be omitted. As a result, improved bending and separation of the block portion are achieved by the recess 22, while simultaneously eliminating the increase in unevenly distributed wear energy.

[0039] In some embodiments, the first recess 22 may be located on the front edge of the block 10, and the block may further comprise a second recess 24 located on the rear edge of the block 10. The addition of the second recess further improves the separation / bending ability of the block. In particular, since the first recess 22 and the second recess 24 are located on opposing edges of the block, the direction of bending of the block can be controlled more precisely.

[0040] In some embodiments, the connecting line 26 between the geometric center 222 of the first recess 22 and the geometric center 242 of the second recess 24 may have an inclination angle of at least 0 degrees and a maximum of 80 degrees with respect to the circumferential direction. Preferably, the inclination angle of the connecting line 26 may be at least 0 degrees and a maximum of 60 degrees. The geometric center is also called the "centroid" and corresponds to the arithmetic mean position of all points on the surface of each recess. The connecting line 26 may correspond to a separation line between the first portion 12 and the second portion 14.

[0041] The connecting line 26 between the geometric centers of the recesses 22 and 24, which have inclination angles within a specific range, provides optimized block bending capability while maintaining the circumferential rigidity of the block.

[0042] In some embodiments, the first recess 22 may have a vertical extension measured perpendicular to the outer surface of the block that contacts the ground when the tire is in a normal state, the vertical extension being at least 20% of the depth of the first groove 18.

[0043] As shown in Figure 2, the tread may further include 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 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 shapes, 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 than the underlying block or portion of the block. Also, some sipes may have walls that extend radially toward the center of the tire, while some sipes may have corrugated, zigzag shapes, etc., in the radial direction. Furthermore, such sipes may be inclined with respect to the radial direction. Some sipes may have projections near the bottom of the sipe. Sipes 30 can trap snow within them and provide an additional edge to the tread. This improves traction on snow-covered ground.

[0044] In some embodiments, the multiple sipes 30 may define an edge component (EI) corresponding to the ratio between the sum of the protruding lengths of the multiple sipes in the axial direction (SAP) and the outer circumference (C) of the tread, thereby,

[0045]

number

[0046] 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 circumference temperature.

[0047] A high edge component provides better ability to capture snow, which improves the tire's traction on snow-covered ground. However, a high edge component also results in low rigidity of the block, which generally deteriorates the 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.

[0048] Preferably, the edge component is balanced with the provision of recesses (if any) and any second grooves. For example, since the recesses locally reduce rigidity, the edge component should stay within the indicated range to ensure sufficient rigidity. Also, since the recesses (if any) contribute to snow capture, fewer sipes, or sipes of shorter length, may be required. If more than one recess per block is provided and / or 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.

[0049] 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 , 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, a higher ratio V V / V R This indicates a larger amount of voids in the tread, which results in lower tread stiffness and therefore benefits snow performance. V / V R A lower void-to-rubber ratio indicates a greater amount of rubber in the tread, which increases rigidity and thus improves braking performance. 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 surfaces as well as good traction on snow-covered surfaces.

[0050] 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, resulting in an overall pattern that is V-shaped. In other embodiments described elsewhere in this specification, the additional blocks may be point-symmetric such that the overall pattern is 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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 road surface, 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 leads to wear.

[0055] As shown in Figure 2, the tread further comprises a plurality of second grooves 20, each of which is positioned between the shoulder portion and the middle portion of each block 10 of the set. In some embodiments, each second groove 20 is positioned substantially circumferentially. In some embodiments, each second groove 20 may be positioned, for example, as a substantially straight line slightly inclined with respect to the circumferential direction, and in other embodiments, as shown, for example in Figure 2, each second groove 20 may be positioned in a zigzag configuration 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, thus improving the distribution of wear energy across the entire axial extension of the block 10.

[0056] Therefore, in a preferred embodiment, the second groove generally serves to separate the shoulder portion of the block 10 from the middle portion of the block 10. For example, during acceleration or braking, the shoulder portion of the block 10 is particularly susceptible to distortion because it is positioned substantially perpendicular to the circumferential direction of the tire. This can lead to deformation of the block 10 in the shoulder portion. Therefore, it is desirable to mechanically separate the shoulder portion of the block 10 from the middle portion 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.

[0057] Therefore, in preferred embodiments, the present invention does not completely exclude any substantially circumferentially arranged grooves (although this is also possible). Rather, in preferred embodiments, substantially circumferential grooves located between two or more inner portions of a block (e.g., an intermediate portion and a central portion) can be omitted and replaced by one or more recesses as described herein.

[0058] Figure 3 shows an enlarged view of the block portion including the recess.

[0059] The block 10 shown in Figure 3 corresponds to one of the blocks 10 in Figure 2. Therefore, the block 10 in Figure 3 also comprises a first portion 12 and a second portion 14, and a first recess 22 located between the first portion 12 and the second portion 14. As shown in Figure 3, the block 10 may further comprise a second recess 24 located between the first portion 12 and the second portion 14. According to Figure 3, each of the recesses 22 and 24 comprises a surface area 25. In Figure 3, the surface area 25 is shown only for the second recess 24 for clarity, but it should be understood that all characteristics described for one recess may apply to other recesses unless otherwise specified.

[0060] In some embodiments, the first recess 22 and / or the second recess 24 are at least 4 mm 2 And up to 60mm2 The surface area 25 may have a surface area 25. Preferably, the first recess 22 and / or the second recess 24 have a surface area of ​​at least 6 mm 2 And up to 50mm 2 It may have a surface region 25.

[0061] This range offers a good trade-off between wear and performance. A larger surface area results in improved performance because bending capacity increases in larger recesses. However, larger recesses also increase localized wear. Therefore, at least 4 mm 2 The recess 22 having a surface area may be configured to achieve increased bending capacity, but the surface area of ​​the recess 22 is preferably up to 60 mm in order to avoid increased wear. 2 It is possible.

[0062] In some embodiments, the first recess 22 and / or the second recess 24 may have an extension of at least 1.5 mm measured perpendicular to the tangent to the block and up to 45% of the width of the block as measured at the axial outer end of the recess. Preferably, the first recess 22 and / or the second recess 24 may have an extension 225 of at least 1.5 mm measured perpendicular to the tangent to the block and up to 35% of the width of the block as measured at the axial outer end of the recess.

[0063] As described above, this provides a good trade-off between wear and performance. A higher extension of the recess, measured perpendicular to the block, results in improved separation / bending properties but also increases localized wear of the tread. Therefore, preferably, an extension of at least 1.5 mm, measured perpendicular to the tangent of the block, may be selected to enhance the separation / bending properties of the block. Furthermore, an extension of up to 45% of the width of the block 10 may be selected. The width of the block may, as herein it is, be measured perpendicular to the tangent of the block and adjacent to the first recess 22. By selecting a width of up to 45% of the block width, the increase in wear can be limited, thereby achieving the desired trade-off between wear and separation / bending properties.

[0064] In some embodiments, the first recess 22 and / or the second recess 24 may have at least one edge inclined at least 0 degrees and up to 30 degrees with respect to the axial direction of the tire (as shown by the inclination angle 227 in Figure 3). Preferably, the first recess 22 and / or the second recess 24 may have at least one edge inclined at at least 5 degrees and up to 20 degrees with respect to the axial direction of the tire.

[0065] Within this inclined range, the edges can contribute to grip on snow-covered ground. Thus, by providing a recess having at least one edge within the above range, the snow performance of the tire can be improved.

[0066] In some embodiments, the first recess 22 and / or the second recess 24 may have outer edges 226, 246 which are the edges of the recess 22, 24 closest to the tire shoulder, and inner edges 228, 248 on the opposite side of the outer edges, wherein for the first recess 22, the outer edge 226 is inclined at 0 to 30 degrees with respect to the axial direction of the tire, and for the second recess 24, the inner edge 248 is inclined at 0 to 30 degrees with respect to the axial direction of the tire.

[0067] The embodiments described above relate to 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. In such embodiments, the recess may be located between any two continuously formed parts, for example, between the first part and the second part, between the second part and the third part, between the third part and the fourth part, and so on.

[0068] Furthermore, while the above-described embodiments include one recess per block edge, alternative embodiments may exist in which two or more smaller recesses are arranged in close proximity to each other on a single edge, thereby behaving similarly to the single recess described in the above-described embodiments.

[0069] Figures 4A to 4E show various embodiments of a block having two recesses between the first and second parts in different arrangements.

[0070] Figures 4A and 4B show embodiments of the present disclosure in which the first recess 22 and the second recess 24 are not aligned in the circumferential direction. This means that there is no plane parallel to the equatorial plane 16 of the tire that cuts through both the first recess 22 and the second recess 24.

[0071] In the embodiment shown in Figure 4A, the first recess 22 is positioned axially inward compared to the second recess 24. In the embodiment shown in Figure 4B, the first recess 22 is positioned axially inward compared to the second recess 24. The embodiments shown in Figures 4A and 4B provide a more uniform distribution of block stiffness across the axial extension of the block.

[0072] Alternatively, Figures 4C and 4D show one embodiment of the present disclosure in which the first recess 22 and the second recess 24 are partially aligned circumferentially. This means that it is possible to construct a plane parallel to the equatorial plane 16 that cuts through both the first recess 22 and the second recess 24, and at the same time, it is possible to construct a plane that is parallel to the equatorial plane but cuts through only one of the first recess 22 or the second recess 24.

[0073] In the embodiment shown in Figure 4C, the first recess 22 is positioned axially inward compared to the second recess 24. In the embodiment shown in Figure 4D, the first recess 22 is positioned axially inward compared to the second recess 24. The embodiments shown in Figures 4C and 4D similarly provide a more uniform distribution of block stiffness across the axial extension of the block.

[0074] Alternatively, Figure 4E shows an embodiment of the present disclosure in which the first recess 22 and the second recess 24 are perfectly aligned circumferentially. This means that a first plane parallel to the equatorial plane 16 of the tire intersects the outer edges of both the first recess 22 and the second recess 24, and a second plane parallel to the equatorial plane 16 of the tire intersects the inner edges of both the first recess 22 and the second recess 24. This embodiment provides particularly improved bending capability of the block in a desired portion, as the block is further narrowed by the perfectly aligned circumferential recesses.

[0075] Figure 5 shows an exemplary embodiment of the V-shaped directional tread pattern according to this disclosure.

[0076] As shown in Figure 5, some embodiments of the tread may include a second set of continuous blocks 50 positioned opposite the equatorial plane 16 of the tire, generally corresponding 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 performance on wet roads. While a directional pattern with a preferred rolling direction is advantageous for wet surfaces, other embodiments are also possible.

[0077] For example, Figure 6 shows an exemplary embodiment of an S-shaped tread pattern according to the present disclosure. 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.

[0078] 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.

[0079] 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 all sizes, 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.

[0080] Next, the tire is loaded under the following load 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 measurement, ink may be applied to the tread profile, then the tire is 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.

[0081] 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 with respect to 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.

[0082] The measurements given in this disclosure refer to measurements taken under footprint conditions on new tires that have not been exposed to wear prior to the measurement. [Explanation of Symbols]

[0083] 10, 50 blocks 12 Part 1 14. Part 2 16 Equatorial plane 18 The first trench 20 The second groove 22, 24 recesses 25 surface area 26 connecting lines 30 sipes 100 tires 110 tread 120 circumferential direction 130 Axis 140 Radial 150 center 222, 242 geometric center 225 Extension 226, 246 Outer edge 227 Tilt angle 228, 248 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, each block including a front edge and a rear edge, A plurality of first grooves arranged around 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 The first part is located in the central part of the tire, The first part comprises a second part which is axially positioned toward the shoulder of the tire, The first part and the second part are formed in a continuous manner. A tire in which a first recess is formed between the first portion and the second portion, and the first recess is located on at least one of the front edge and the rear edge of the block.

2. The first recess is at least 4 mm ２ And up to 60 mm ２ The tire according to claim 1, having a surface area.

3. The tire according to claim 1 or 2, wherein the first recess has an extension of at least 1.5 mm measured perpendicular to the tangent to the block, and up to 45% of the width of the block as measured at the axial outer end of the recess.

4. The tire according to any one of claims 1 to 3, wherein the first recess has at least one edge that is inclined at least 0 degrees and at most 30 degrees with respect to the axial direction of the tire.

5. The tire according to any one of claims 1 to 4, wherein the first recess is located on the front edge of the block, and the block further has a second recess located on the rear edge of the block.

6. The tire according to claim 5, wherein the connecting line between the geometric center of the first recess and the geometric center of the second recess has an inclination angle of at least 0 degrees and at most 80 degrees with respect to the circumferential direction.

7. The tire according to claim 5, wherein the first recess and the second recess are arranged such that a plane parallel to the equatorial plane of the tire intersects both the first recess and the second recess.

8. The tire according to claim 5, wherein both the first recess and the second recess have an outer edge which is the edge of the recess closest to the shoulder of the tire, and an inner edge opposite the outer edge, and a first plane parallel to the equatorial plane of the tire intersects with the outer edges of both the first recess and the second recess, and a second plane parallel to the equatorial plane of the tire intersects with the inner edges of both the first recess and the second recess.

9. The second recess is, (a) at least 4 mm ２ And up to 60 mm ２ surface region, (b) An extension of at least 1.5 mm measured perpendicular to the tangent to the block, and up to 45% of the width of the block as measured at the axial outer end of the recess, (c) The tire according to any one of claims 5 to 8, having at least one edge that is inclined at least 0 degrees and at most 30 degrees with respect to the axial direction of the tire.

10. The tire according to any one of claims 5 to 9, wherein both the first recess and the second recess have an outer edge portion which is the edge of the recess closest to the shoulder of the tire, and an inner edge portion which is opposite to the outer edge portion, wherein, for the first recess, the outer edge portion is inclined at least 0 degrees and at most 30 degrees with respect to the axial direction of the tire, and for the second recess, the inner edge portion is inclined at least 0 degrees and at most 30 degrees with respect to the axial direction of the tire.

11. The tire according to any one of claims 1 to 10, wherein the first recess has a vertical extension measured perpendicular to the outer surface of the block that is in contact with the ground when the tire is rolling, and the vertical extension is at least 20% of the depth of the first groove.

12. The aforementioned tread, A plurality of sipes that define an edge component EI corresponding to the ratio between the sum of the projected lengths of the plurality of sipes in the axial direction SAP and the outer circumference C of the tread, thereby, [Math 1] The tire according to any one of claims 1 to 11, further comprising a plurality of sipes, wherein the EI is at least 2 and at most 20.

13. The tire according to any one of claims 1 to 12, wherein the ratio of void volume to rubber volume is at least 0.20 and at most 0.40, preferably at least 0.28 and at most 0.35.

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