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 circumference of the tire and a plurality of first grooves arranged along the circumference of the tire, each of the plurality of first grooves being located between two blocks of the set of continuous blocks. Each set of continuous blocks comprises a leading edge and a trailing edge. Each leading edge and trailing edge comprises a first portion located in the shoulder region of the tire, a second portion located axially inward of the first portion, and a third portion located axially inward of the second portion. Each set of continuous blocks further comprises a first chamfered portion located on at least one of the leading edge and the trailing edge. The first chamfered portion has a first average width in the first portion, a second average width in the second portion, and a third average width in the third portion. The first average width projected circumferentially of the tire corresponds to the first projected average width, the second average width projected circumferentially of the tire corresponds to the second projected average width, and the third average width projected circumferentially of the tire corresponds to the third projected average width. At least two of the first, second, and third projected average widths are substantially equal.

Description

[Technical Field]

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

[0002] All-season tires (used here as a typical example for ease of reading) are known for providing good grip on snow-covered roads while also performing well on dry and wet surfaces. 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 that have grooves extending 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, resulting in contact between the tire blocks and the road surface. This contact between the blocks and the road is necessary to provide lateral road holding and, furthermore, to provide friction that allows the driver to control the vehicle's movement through acceleration, braking, and / or steering.

[0004] Furthermore, all-season tires are known to have sipes, which are small cuts within the blocks that extend substantially axially. Such sipes are configured to trap snow within them, providing 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, all-season tires typically have only a few sipes per block, preferably only one sipe per block.

[0005] To improve braking performance, the trailing edge of the tire block can be chamfered, which allows the effective block surface area on the ground to be increased by utilizing the deformation of the tire during braking. However, the chamfered portion may also reduce the traction force of the tire on wet and dry ground.

[0006] Furthermore, since the blocks may be inclined with respect to the circumferential direction of the tire, the circumferential stress applied to the blocks generally varies along the axial extension of the blocks, which can result in an uneven distribution of wear energy across the axial width of the tread.

[0007] Therefore, it is desirable to provide a tire that has improved braking performance while resulting in a more uniform distribution of wear energy. [Overview of the project]

[0008] This objective is achieved by providing an improved vehicle tire as described in the independent claim. Further embodiments are described in the dependent claims.

[0009] 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 circumference of the tire and a plurality of first grooves arranged along the circumference of the tire, each of the plurality of first grooves being located between two blocks of the set of continuous blocks. Each set of continuous blocks comprises a leading edge and a trailing edge. Each leading edge and trailing edge comprises a first portion located in the shoulder region of the tire, a second portion located axially inward of the first portion, and a third portion located axially inward of the second portion. Each set of continuous blocks further comprises a first chamfered portion located on at least one of the leading edge and the trailing edge. The first chamfered portion has a first average width in the first portion, a second average width in the second portion, and a third average width in the third portion. The first average width projected circumferentially of the tire corresponds to the first projected average width, the second average width projected circumferentially of the tire corresponds to the second projected average width, and the third average width projected circumferentially of the tire corresponds to the third projected average width. At least two of the first, second, and third projected average widths are substantially equal.

[0010] Such tires can improve braking performance, particularly on wet and dry surfaces, due to the chamfered edges. Since the projected average chamfer width is substantially equal for at least two of the three portions of each edge, block deformation is reduced. In this way, the average chamfer width directly corresponds to the angle of inclination of each edge with respect to the circumferential direction. That is, portions with a greater inclination with respect to the circumferential direction have a smaller (non-protruding) average chamfer width (sometimes referred to as "smaller chamfers" below) than portions with a smaller inclination with respect to the circumferential direction. Correspondingly, portions with a smaller inclination with respect to the circumferential direction are provided with chamfered edges having a larger (non-protruding) average width (sometimes referred to as "wider chamfers" below).

[0011] The more inclined portions of the tire generally experience higher circumferential stress during normal tire rotation and therefore suffer the most excessive strain. Consequently, smaller chamfers should be applied here to locally increase the block's rigidity and make the more inclined block portions more resistant to higher stresses. Conversely, portions with less inclination generally experience less circumferential stress and therefore allow for wider chamfers, which is advantageous for braking and steering performance.

[0012] In other words, by providing chamfered sections such that the projected mean chamfer width is substantially equal for at least two of the three sections, the response to stress applied in the circumferential direction becomes more uniform, and therefore the distribution of wear energy across the width of the tread becomes more uniform. [Brief explanation of the drawing]

[0013] [Figure 1] A schematic diagram of a vehicle tire according to this disclosure is shown. [Figure 2] The half-tread profile of the tire according to this disclosure is shown. [Figure 3] Figure 2 shows the individual blocks of the set of consecutive blocks. [Figure 4A] Figure 3 shows three cross-sectional views of different parts of the block. [Figure 4B] Figure 3 shows three cross-sectional views of different parts of the block. [Figure 4C] Figure 3 shows three cross-sectional views of different parts of the block. [Figure 5] An enlarged view of an exemplary chamfered portion according to this disclosure is shown. [Figure 6] This disclosure shows the tire footprint. [Figure 7] This disclosure illustrates exemplary embodiments of the V-shaped directional tread pattern. [Figure 8] This disclosure illustrates exemplary embodiments of the S-shaped tread pattern.

Best Mode for Carrying Out the Invention

[0014] In order to overcome the drawbacks of the prior art as described above, it may be desirable to provide a chamfer having a projected average width in three portions, the projected average width being substantially constant in at least two of the three portions.

[0015] Within the context of the present disclosure, a "chamfer" means an inclined side wall of a block that extends radially inwards from the outer block surface. The wall is inclined such that the width of the block measured circumferentially increases towards the bottom of the groove. Each chamfer is defined by a height and a width. The chamfer height may correspond to the distance measured radially between the outer block surface and the radially innermost end of the inclined wall. The height of the chamfer (= the distance between the outer block surface and the radially innermost end of the inclined wall) is typically lower than the total height of the block and can be, for example, at most 50% or less of the total height of the block. The width of the chamfer may be measured perpendicular to the block and corresponds to the width of the inclined chamfer wall when projected onto the outer tread surface. This width is also referred to in the present disclosure as the "(non-projecting) chamfer width" for clarity.

[0016] The blocks of a tire tread generally have portions of varying inclination across the axial extension of the tread. By varying the inclination, the circumferential stress applied to portions of the block changes, and portions of the block having a greater inclination relative to the circumferential direction receive a greater stress than portions of the block having a smaller inclination relative to the circumferential direction.

[0017] Therefore, it may be desirable to provide a chamfer on at least one edge of the block, which has a substantially equal projected mean chamfer width in at least two of the three portions of the edge. Since wear energy is reduced particularly in the more inclined (with respect to the circumferential direction) portion of the block that is subjected to the most circumferential stress, this can improve braking performance while providing a more uniform and optimized wear state with a larger chamfer on the more inclined portion of the edge.

[0018] In other words, this disclosure provides an improved synergistic effect between braking performance on the one hand and the reduction and optimization of wear energy on the other hand.

[0019] Figure 1 shows 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 grooves 12 positioned between two blocks 10 of the set of continuous blocks. Furthermore, sipes 14 may be positioned within each of the sets of continuous blocks 10.

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

[0022] A "groove" represents a cut within 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 smaller. 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 in the radially inward direction. 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), although this is not necessarily the case. For example, a depth of at least 1 mm, preferably at least 3 mm, is conceivable.

[0023] The term "sipe" also refers to an indentation within 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 in the radially inward direction. The depth of a sipe may also vary, and sometimes a sipe may extend to its full depth, 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.

[0024] In the context of this disclosure, “circumferential direction” 120 means a direction parallel to the direction in which the tire normally rotates, i.e., a direction perpendicular to the axial direction 130 which is parallel to the tangential direction to the circumference of the tire. With respect to Figure 1, the circumferential direction 120 is therefore a direction 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 on which the tire is typically 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 angle numbers given herein should be considered absolute values, that is, not limited to the direction of each angle.

[0029] Figure 2 shows the half-tread profile of the tire according to this disclosure.

[0030] As shown in Figure 2, the tread has a set of continuous blocks 10 arranged along the circumference of the tire. In the context of this disclosure, “continuous blocks” means that the tread has a plurality of blocks that are continuous with one another along the circumference of the tire. While the invention according to this disclosure is preferably provided for all blocks of the tire, some blocks that may be arranged between the individual blocks 10 of the set of continuous blocks may not have the chamfered portion according to the present invention.

[0031] Generally, the block 10 is intended to provide contact with the ground when the tire is rotating. 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.

[0032] As shown in Figure 2, the tread further comprises a plurality of first grooves 12 arranged around the circumference of the tire, each of which is located between two blocks 10 of a continuous set of blocks. Preferably, the grooves 12 begin near the equatorial plane 16 of the tire, extend toward the shoulder end of the tread, and open at the outer edge of the tire. The grooves 12 are generally defined by adjacent blocks 10.

[0033] The primary purpose of the grooves 12 is to drain water from the contact patch by guiding water along the grooves 12 toward the tire's shoulder as the tire rotates on the road surface, and releasing the water from there. In this way, the grooves 12 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 enabling improved wear performance, resulting in reduced slippage of the blocks on the ground and a decrease in the abrasion effect that leads to wear.

[0034] The tire in Figure 2 may further include a second groove 250 extending through each of the sets of continuous blocks 10 and connecting two consecutive first grooves 12. By providing such a second groove, it is possible to separate the portion of the block 10 near the shoulder of the tire from the more central portion. This allows for better braking performance, and also improves steering and lateral road holding, as the portion of the block 10 that is mainly involved in braking, i.e., the portion near the shoulder, is mechanically separated from the more central portion that is mainly involved in steering and lateral road holding.

[0035] As further shown in Figure 2, the tread may further comprise a plurality of sipes 14. In the illustrated tread pattern, each of the plurality of sipes 14 may preferably extend substantially along the shape of each set of continuous blocks 10. However, other arrangements and shapes of sipes on the outer tread surface are also possible, such as corrugated, zigzag, etc. Sipes do not necessarily have to follow the shape of the blocks. For example, sipes may be included only along a portion of the shape of the block, or may have a different angle of inclination with respect to the circumferential direction than the 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 also have corrugated, zigzag, etc., shapes in the radial direction. Furthermore, such sipes may also be inclined with respect to the radial direction. Some sipes may have projections near the bottom of the sipe.

[0036] The 14 sipes can trap snow within them, providing an additional edge to the tread. This improves traction on snow-covered ground.

[0037] In some embodiments, the multiple sipes 14 have an edge component (EI) that corresponds to the ratio between the sum of the projected lengths of the multiple sipes in the axial direction (SAP) and the circumference of the tread (C),

[0038]

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[0039] 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.

[0040] A high edge component provides a better ability to capture snow, which improves the traction of the tire on snow-covered ground. However, a high edge component also results in a low rigidity of the block, which generally deteriorates the braking / acceleration performance on dry ground. The edge component within one of the above ranges provides a particularly good balance between the traction on snow-covered ground and the braking / acceleration performance on dry ground.

[0041] In some embodiments, 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 a volume of rubber provided in the tread, and these may together constitute the total volume of the tread. That is, the total volume of the tire is V T where 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 can be at least 0.20 and at most 0.40. Preferably, the ratio V V / V R can be at least 0.24 and at most 0.37, more preferably at least 0.28 and at most 0.35.

[0042] The ratio V V / VR is directly related to the rigidity of the tread profile. Thus, a higher ratio V V / V R indicates a greater amount of voids in the tread, which results in a lower rigidity of the tread and thus benefits the snow performance. The ratio V V / V RA lower void-to-rubber ratio indicates a greater amount of rubber in the tread, which increases rigidity and therefore improves braking performance. A void-to-rubber ratio within a specific range provides an optimal trade-off between snow and dry performance, resulting in a tire that exhibits good braking performance on dry ground as well as good traction on snow-covered ground.

[0043] Figure 3 shows the individual blocks of the set of consecutive blocks in Figure 2.

[0044] According to Figure 3, block 10 comprises a leading edge 20 and a trailing edge 30.

[0045] In the context of this disclosure, “leading edge” may also be referred to as “traction edge,” and refers to the edge of the 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, rotating in the preferred rotational direction, enters the tire-to-ground contact patch.

[0046] 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, rotating in the preferred direction of rotation, leaves the tire's contact patch with the ground.

[0047] The leading edge 20 comprises a first portion 22 located in the shoulder region of the tire, a second portion 24 located axially inward of the first portion 22, and a third portion 26 located axially inward of the second portion 24. The trailing edge 30 comprises a first portion 32 located in the shoulder region of the tire, a second portion 34 located axially inward of the first portion 32, and a third portion 36 located axially inward of the second portion 34.

[0048] The first portions 22, 32 of the leading edge 20 and the trailing edge 30 may be referred to as the "shoulder portion," the second portions 24, 34 of the leading edge 20 and the trailing edge 30 may be referred to as the "intermediate portion," and the third portions 26, 36 of the leading edge 20 and the trailing edge 30 may be referred to as the "central portion." The central portion may be positioned adjacent to the equatorial plane 16 of the tire.

[0049] As shown in Figure 3, the axial extensions of the corresponding edge portions may differ between the edges; that is, as shown in Figure 3, the second portion 34 of the rear edge 30 may have a larger axial extension than the corresponding second portion 24 of the front edge 20. Generally, the third portions 26, 36 of the front edge 20 and the rear edge 30 may have axial extensions of at least 25% and up to 40% of half the tire footprint width. Thus, the third portions 26, 36 preferably begin adjacent to the equatorial plane 16 of the tire and extend axially outward to a width of 25% to 40% of half the tire footprint width.

[0050] The second portions 24, 34 of the leading edge 20 and the trailing edge 30 may have axial extensions of at least 25% and up to 55% of half the tire footprint width. Thus, the second portions 24, 34 preferably begin from the axially outer ends of the third portions 26, 36 and extend axially outward to a width of 65% to 80% of half the tire footprint width.

[0051] The first portions 22, 32 of the leading edge 20 and the trailing edge 30 may have axial extensions of at least 20% and up to 35% of half the tire footprint width. Thus, the first portions 22, 32 preferably begin at the axially outer ends of the second portions 24, 34 and extend axially outward to the axially outer ends of the tire, i.e., cover the entire axially outward portion of half the footprint width from the second portions 24, 34.

[0052] In some embodiments, the separation between the two portions, the leading edge and the trailing edge, can be defined by any one of the following: - Recesses at the edges of adjacent parts, - Changes in the inclination angle of each edge of the tire with respect to the circumferential direction, - The direction or magnitude of the curvature of each edge, - Gradual increase or decrease in chamfer width, - Grooves extending substantially circumferentially through the block, or -A combination of those.

[0053] For example, as shown in Figure 3, the recess 222 can separate the second portion 24 of the leading edge 20 from the third portion 26 of the leading edge 20. Furthermore, the recess 224 can separate the first portion 22 of the leading edge 20 from the second portion 24 of the leading edge 20. Similarly, the recess 322 can separate the second portion 34 of the trailing edge 30 from the third portion 36 of the trailing edge, and the recess 324 can separate the first portion 32 of the trailing edge 30 from the second portion 34 of the trailing edge 30.

[0054] Alternatively, other means of separation between the edge portions are also possible. For example, as shown in Figure 3, a groove 250 extending substantially circumferentially through the block 10 can separate the first portions 22, 32 from the second portions 24, 34. Although such a groove is shown only in Figure 3 for separating the first portions 22, 32 from the second portions 24, 34, a similar groove may also be placed between the second portions 24, 34 and the third portions 26, 36.

[0055] Furthermore, although Figure 3 only shows recesses 222, 224, 322, 324 and grooves 250 as means for separating adjacent edge portions, other means such as gradually increasing or decreasing the chamfer width can be used.

[0056] Alternatively, changes in the direction or magnitude of the curvature of each edge can be used, namely changes between concave and convex curvature, as well as increases or decreases in edge curvature, to separate two adjacent edge portions.

[0057] Furthermore, the angle of inclination of each block relative to the circumferential direction of the tire can be used to determine the separation between the edge portions.

[0058] According to one approach, the inclination angle of each portion of the edge is determined by the angle between (i) the tangent applied to each edge of the block and (ii) the circumferential direction of the tire. If each portion of the edge has a chamfer, the tangent is applied to the outermost circumferential end of the block (negligible for the width and shape of the chamfer). This approach can be used when each portion of the edge is formed continuously or substantially continuously, i.e., without substantial circumferential cuts in between, and each edge exhibits a discontinuity in its inclination with respect to the circumferential direction of the tire, e.g., a significant change. In this case, the discontinuity corresponds to a separation between adjacent edge portions.

[0059] Preferably, the inclination angles of the first portions 22, 32 (i.e., the inclination angles of the tangents on each portion of the edge with respect to the circumferential direction) may be at least 65° and a maximum of 90° with respect to the circumferential direction, preferably 75° and a maximum of 90°, and more preferably at least 85° and a maximum of 90° with respect to the circumferential direction. The inclination angles of the second portions 24, 34 may be at least 50° and a maximum of 65° with respect to the circumferential direction. Preferably, the inclination angles of the second portions 24, 34 may be at least 50° and a maximum of 60° with respect to the circumferential direction. The inclination angles of the third portions 26, 36 may be at least 20° and a maximum of 50° with respect to the circumferential direction. Preferably, the inclination angles of the third portions 26, 36 may be at least 30° and a maximum of 50° with respect to the circumferential direction.

[0060] According to another approach that may be used when each edge does not exhibit discontinuity in its inclination with respect to the circumferential direction of the tire, the separation between edge portions is preferably determined according to an axial extension of the footprint width as described above in relation to Figure 3, a recess in each edge, the direction or magnitude of the curvature of each edge, a gradual increase or decrease in the chamfer width, or a groove that extends substantially circumferentially through the block.

[0061] More preferably, in this approach, the inclination angle may be used in addition to one or more of the aforementioned criteria. For example, third portions 26, 36, starting adjacent to the equatorial plane of the tire and extending axially outward to a width of 25% to 40% of half the tire footprint width shown, exhibit an inclination angle of at least 20° and a maximum of 50° with respect to the circumferential direction, preferably at least 30° and a maximum of 50° with respect to the circumferential direction, for at least one of the possible extensions within this range. Similarly, second portions 24, 34, starting at the axially outer end of the third portion and extending axially outward to a width of 65% to 80% of half the tire footprint width, exhibit an inclination angle of at least 50° and a maximum of 65° with respect to the circumferential direction, preferably at least 50° and a maximum of 60°. Similarly, the first portions 22, 32, which begin at the axial outer end of the second portion and extend axially outward to the axial outer end of the tire, exhibit an inclination angle of at least 65° and a maximum of 90° with respect to the circumferential direction, preferably 75° and a maximum of 90° with respect to the circumferential direction, and more preferably at least 85° and a maximum of 90° with respect to the circumferential direction.

[0062] Furthermore, various combinations of means for separating the edge portions are also possible. As an example, Figure 3 shows a combination of recesses 224, 324 and grooves 250 for separating the first portions 22, 32 and the second portions 24, 34, and there are other possible combinations.

[0063] As shown in Figure 3, the block 10 further comprises a first chamfer 25. Preferably, the first chamfer 25 may be located on the leading edge 20. However, the first chamfer may also be located on the trailing edge 30, as indicated by the second chamfer 35. In some embodiments, the block may comprise both the first chamfer 25 located on the leading edge 20 and the second chamfer 35 located on the trailing edge 30.

[0064] The first chamfered portion 25 has a first average width in the first part, a second average width in the second part, and a third average width in the third part.

[0065] The width of the chamfer refers to the width measured perpendicular to each block edge, as described above. The average width of the chamfer in a given section can be defined by measuring the width of each chamfer at multiple points within the section of each edge and dividing by the number of points. Mathematically, the average width of the chamfer in a section is...

[0066]

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[0068] Figure 3 further shows the three cutting lines CS1, CS2, and CS3. Figures 4A to 4C show three cross-sections of different parts of the block in Figure 3.

[0069] As shown in Figures 4A to 4C, block 10 may have chamfered portions of different widths in different parts.

[0070] Figure 4A shows a cross-sectional view of block 10 cut along line CS1. Thus, Figure 4A shows the first chamfer 25 in the first portion 22 of the front edge 20 of block 10, and the second chamfer 35 located in the first portion 32 of the rear edge 30 of block 10. As described above, the chamfer width is measured perpendicular to the block tangent. Figure 4A shows the first average width 212 of the first chamfer 25 in the first portion 22 of the front edge 20, and the fourth average width 312 of the second chamfer 35 in the first portion 32 of the rear edge 30.

[0071] Figure 4B shows a cross-sectional view of block 10 cut along line CS2. Thus, Figure 4B shows the first chamfer 25 in the second portion 24 of the front edge 20 of block 10, and the second chamfer 35 located in the second portion 34 of the rear edge 30 of block 10. Figure 4B shows the second average width 214 of the first chamfer 25 in the second portion 24 of the front edge 20, and the fifth average width 314 of the second chamfer 35 in the second portion 34 of the rear edge 30.

[0072] Figure 4C shows a cross-sectional view of block 10 cut along line CS3. Thus, Figure 4C shows the first chamfer 25 in the third portion 26 of the front edge 20 of block 10, and the second chamfer 35 located in the third portion 36 of the rear edge 30 of block 10. Figure 4C shows the third average width 216 of the first chamfer 25 in the third portion 26 of the front edge 20, and the sixth average width 316 of the second chamfer 35 in the second portion 34 of the rear edge 30.

[0073] The widths of the first chamfer 25 and the second chamfer 35 may vary within a particular portion. For example, the first chamfer 25 may have a first width at a first position within the first portion 22 of the leading edge 20, and a second width different from the first width at a second position within the first portion 22 of the leading edge 20. The same applies to the second chamfer 35.

[0074] Therefore, the average width of the chamfer can be calculated for each section as specified above. For simplicity, the cross-sectional views shown in Figures 4A to 4C show three cross-sections of different parts of the block in Figure 3, and are thought to represent the cross-sections at the locations where the chamfer locally has its respective average width in each section.

[0075] The projected chamfer width is generally,

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[0077] The first average width projected circumferentially of the tire corresponds to the first projected average width, the second average width projected circumferentially of the tire corresponds to the second projected average width, and the third average width projected circumferentially of the tire corresponds to the third projected average width.

[0078] Chamfer width w i and inclination angle φ i If is constant over portion i, then projected average width

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[0081] If each edge is curved (φ depends on x), or if the chamfer width changes over the extension of each edge portion (w depends on x), the projected average width can be calculated (according to equation (2)) as follows:

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[0083] Figure 5 shows an enlarged view of an exemplary chamfered portion according to this disclosure.

[0084] For simplicity, the block itself is not shown in Figure 5. However, it will be understood that the chamfer is applied to the edge of the block. The reference numerals used in Figure 5 correspond to the reference numerals used for the first chamfer 25 on the leading edge 20. However, it should be understood that the same quantities described in Figure 5 may also be applied to the second chamfer 35 on the trailing edge 30.

[0085] Furthermore, for the sake of simplification, the chamfered portion shown in Figure 5 is assumed to have a constant width in each individual part, and the angle of inclination is constant in each individual part.

[0086] The chamfered portion 25 of the first part 22 of the leading edge 20 has a first average width 212

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[0090] In other words, if each edge portion has an inclination angle of 90° with respect to the equatorial plane, the average width is equal to the projected average width.

[0091] Similarly, the chamfered portion 25 has a second average width 214 in the second portion 24 of the front edge 20.

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[0095] Furthermore, the chamfered portion 25 has a third average width 216 in the third portion 26 of the front edge 20.

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[0099] According to Figure 5, the first projection average width is 222

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[0103] For example, the third average width 216 of the first chamfered portion 25 in the third portion 26 may be greater than the second average width 214 of the first chamfered portion 25 in the second portion 24. Furthermore, the second average width 214 of the first chamfered portion 25 in the second portion 24 may be greater than the first average width 212 of the first chamfered portion 25 in the first portion 22.

[0104] As described above, this configuration results in improved braking and traction performance, as well as reduced and more uniformly distributed wear energy across the width of the tread, because the average chamfer width directly corresponds to the inclination angle of each edge relative to the circumferential direction. Thus, stresses occurring in different parts of the tire blocks are effectively compensated.

[0105] In some embodiments, the first chamfered portion 25 may be positioned on the leading edge 20 of the block 10. Chamfered portions on the leading edge have been shown to work efficiently to contribute to traction, particularly on snow-covered ground. In general, to increase traction on snow-covered ground, it is necessary to reduce the surface area of ​​the block so that the contact pressure between the block surface and the ground can be increased. Placing the chamfered portion on the leading edge has been shown to be a good position for reducing the surface area of ​​the block. The increase in contact pressure provided by the chamfered portion on the leading edge, which results in a peak in contact pressure, particularly at the leading edge of the block, allows the block, and especially its leading edge, to dig into the snow more efficiently, and thus increases the traction of the tire on snow-covered ground. Therefore, positioning it on the leading edge particularly improves traction.

[0106] In some embodiments, the block 10 may further comprise a second chamfered portion 35 located on the rear edge 30 of the block 10. The chamfered portion on the rear edge contributes to dry braking performance. As the vehicle brakes, the tread blocks deform and bend due to the inertia of the vehicle's mass. In this way, some of the rubber surfaces located near the front edge of the block lose contact with the road surface, and thus the contact surface of each block decreases. A decrease in the contact surface reduces the frictional force, and thus the braking performance of the tire is impaired. By providing a chamfered portion on the rear edge, the inclined surface of the chamfered portion is pushed toward the ground during braking as the block bends, and thus the rubber surface in contact with the ground increases. In this way, surface loss at the front of the block can be compensated for, the contact surface increases, and this results in better braking performance due to the increased frictional force. As a result, the chamfered portion on the rear edge of the block contributes to both dry and wet braking performance.

[0107] The second chamfered portion 35 may have a fourth average width 312 in the first portion 32 of the rear edge 30, a fifth average width 314 in the second portion 34 of the rear edge 30, and a sixth average width 316 in the third portion 36 of the rear edge 30. Similarly, the fourth average width 312 projected in the circumferential direction of the tire may correspond to the fourth projected average width, the fifth average width 314 projected in the circumferential direction of the tire may correspond to the fifth projected average width, and the sixth average width 316 projected in the circumferential direction of the tire may correspond to the sixth projected average width. At least two of the fourth projected average width, the fifth projected average width, and the sixth projected average width may be substantially equal.

[0108] The projected average width of the second chamfered portion 35 can be determined in the same manner as described with reference to Figure 5 and the projected average widths 222, 224, and 226.

[0109] Preferably, the fourth projected average width, the fifth projected average width, and the sixth projected average width may be substantially equal.

[0110] In this case, the fourth average width 316 of the second chamfered portion 35 in the third portion 36 may be greater than the second average width 314 of the second chamfered portion 35 in the second portion 34. Also, the second average width 314 of the second chamfered portion 35 in the second portion 34 may be greater than the first average width 312 of the second chamfered portion 35 in the first portion 32.

[0111] This configuration provides further improved braking and traction performance, as well as reduced and more evenly distributed wear energy across the width of the tread.

[0112] In some embodiments, at least one of the first projected average width 222, the second projected average width 224, and the third projected average width 226 may be at least 1 mm and up to 3.5 mm, preferably at least 1 mm and up to 2 mm. The projected average width is related to the chamfer width. Within a given range, they ensure an optimal balance between dry, wet wear, and snow performance.

[0113] The embodiments described above concern blocks having three parts, but blocks having more parts, such as four or more parts, are also possible. This can be achieved, for example, by subdivision, i.e., by dividing a part into one or more continuously formed subparts.

[0114] Figure 6 shows the tire footprint according to this disclosure.

[0115] The procedure for measuring tire footprints as described herein is described elsewhere in this specification.

[0116] The footprint shown in Figure 6 represents the continuous block 10 and the groove 12 between sets of continuous blocks. The gaps between the continuous blocks consist of the groove 12 and chamfered portions 25 and 35 that may be located on the leading edge 20 and / or trailing edge 30.

[0117] As shown in Figure 6, the footprint may include the footprint width W measured axially at the widest axial extension of the footprint. The footprint in Figure 6 may further include a central region C that occupies up to 80% of the footprint width, and the central region has two outer edges located at both ends of the central region in the axial direction.

[0118] The footprint shown in Figure 6 may further comprise two outer lengths LE1 and LE2, measured circumferentially at the outer edge of the central region C. Thus, the footprint may have an average footprint length corresponding to the average of the two outer lengths.

[0119]

number

[0120] Therefore, tire footprint ratio

[0121]

number

[0122] The tire footprint ratio can be considered a measure of the "roundness" of the footprint; a lower tire footprint ratio suggests a rounder footprint, while a higher ratio suggests a more rectangular footprint. Therefore, the tire footprint ratio indicates the effect of traction / braking forces on the tread blocks, particularly in the area near the tire shoulders.

[0123] A more rectangular footprint can lead to higher stress being applied to the shoulder and mid-section, particularly during braking. Therefore, the tire footprint ratio can be associated with a preferred chamfer width; a wider chamfer may be more beneficial for braking performance with a more rectangular footprint, while the opposite is true for a rounder footprint.

[0124] Figure 7 shows an exemplary embodiment of the V-shaped directional tread pattern according to this disclosure.

[0125] As shown in Figure 7, some embodiments of the tread may include a second set of continuous blocks 50, which generally corresponds to a first set of continuous blocks 10, positioned opposite the equatorial plane 16 of the tire. In some embodiments, as shown in Figure 7, the second set of continuous blocks 50 may be axially symmetric with respect to the first set of blocks 10, resulting in a V-shaped tread pattern with a preferred rotational 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 opposing axial directions of the tread when the tire rotates in the preferred rotational direction. This can improve traction performance on wet roads. While a directional pattern with a preferred rotational direction is advantageous on wet surfaces, other embodiments are also possible.

[0126] For example, Figure 8 shows an exemplary embodiment of an S-shaped tread pattern according to the present disclosure. In some embodiments, according to Figure 8, 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 direction of rotation.

[0127] 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 contour 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.

[0128] 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, trucks, etc., the standardized inflation pressures set by the European Tire and Rim Technology Organization (ETRTO) are used. All measurements are taken at room temperature.

[0129] Next, loads are applied to the tires under the following conditions: For passenger car radial tires, a weight equivalent to 88% of the tire load index according to the ETRTO chart is applied to the tire. Tires for commercial vans, trucks, etc., are loaded with a weight corresponding to the ETRTO single load rating standard. To perform the measurements, ink is applied to the tread profile, and then the tire is pressed onto a card according to the above specifications, leaving an analyzable ink footprint. The footprint is evaluated for three tire sections placed at equal intervals of 120° around the circumference of the tire. The metrics analyzed within the footprint are then averaged across the three measured sections.

[0130] Measurement of tire void volume and rubber volume In the context of this application, the tire void volume is also measured under footprint conditions. That is, the tire is inflated in the same manner as described above for tire footprint measurement. The void volume is measured for each pixel by a laser measurement system capable of detecting its relative depth to the tread surface. This allows the total void volume within the contact patch to 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. The total rubber volume is the difference between the total tread volume and the total void volume.

[0131] 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]

[0132] 10.50 blocks 12 The first groove 14 sipes 16 Equatorial plane 20 Leading edge 22,32 Part 1 24,34 Part 2 25 First chamfered section 26,36 Third part 30 Trailing edge 35 Second chamfered section 100 tires 110 tread 120 circumferential direction 130 Axis 140 Radial 150 center 212 1st average width 214 Second average width 216 Third average width 222,224,322,324 recesses 250 Second groove 312 The fourth average width 314 5th average width 316 6th average width

Claims

1. A vehicle tire including a tread, wherein the tread is A set of continuous blocks arranged along the circumference of the aforementioned tire, A plurality of first grooves arranged along the circumference of the tire, wherein each of the plurality of first grooves is positioned between two blocks of the set of continuous blocks, Equipped with, Each of the aforementioned sets of consecutive blocks is The leading edge and the trailing edge, Each leading and trailing edge comprises a first portion located in the shoulder region of the tire, a second portion located axially inward of the first portion, and a third portion located axially inward of the second portion. The leading edge and the trailing edge, A first chamfered portion is provided on at least one of the front edge and the rear edge, Equipped with, The first chamfered portion has a first average width in the first part, a second average width in the second part, and a third average width in the third part. The first average width projected in the circumferential direction of the tire corresponds to the first projected average width, the second average width projected in the circumferential direction of the tire corresponds to the second projected average width, and the third average width projected in the circumferential direction of the tire corresponds to the third projected average width. At least two of the first projected average width, the second projected average width, and the third projected average width are substantially equal, tire.

2. The tire according to claim 1, wherein the first projected average width, the second projected average width, and the third projected average width are substantially equal.

3. The tire according to any one of claims 1 to 2, wherein at least one of the first projected average width, the second projected average width, and the third projected average width is at least 1 mm and at most 3.5 mm.

4. The tire according to any one of claims 1 to 3, wherein the third average width of the first chamfered portion in the third portion is greater than the second average width of the first chamfered portion in the second portion.

5. The tire according to any one of claims 1 to 4, wherein the second average width of the first chamfered portion in the second portion is greater than the first average width of the first chamfered portion in the first portion.

6. The tire according to any one of claims 1 to 5, wherein the first chamfered portion is positioned on the front edge of the block.

7. The tire according to claim 6, further comprising a second chamfered portion disposed on the rear edge of the block.

8. The second chamfered portion has a fourth average width in the first portion of the trailing edge, a fifth average width in the second portion of the trailing edge, and a sixth average width in the third portion of the trailing edge. The fourth average width projected in the circumferential direction of the tire corresponds to the fourth projected average width, the fifth average width projected in the circumferential direction of the tire corresponds to the fifth projected average width, and the sixth average width projected in the circumferential direction of the tire corresponds to the sixth projected average width. At least two of the fourth projected mean width, the fifth projected mean width, and the sixth projected mean width are substantially equal, The tire according to claim 7.

9. The tire according to claim 8, wherein the fourth projected average width, the fifth projected average width, and the sixth projected average width are substantially equal.

10. When the tire is in contact with the road under normal conditions, a footprint area is defined, and the footprint area is The footprint width measured in the axial direction at the widest axial extension of the footprint, A central region comprising 80% of the footprint width, having two outer edges located at both ends of the central region in the axial direction, Two outer lengths measured circumferentially at the outer edge of the central region, The average footprint length corresponding to the average of the two outer lengths, A tire footprint ratio defined as the ratio between the average footprint length and the footprint width, wherein the tire footprint ratio is at least 0.6 and at most 1.0, A tire according to any one of claims 1 to 9, comprising:

11. The third portion of the front edge or the rear edge has an axial extension of at least 25% and up to 40% of half the footprint width of the tire, The second portion of the leading or trailing edge has an axial extension of at least 25% and a maximum of 55% of half the footprint width of the tire, The first portion of the leading or trailing edge has an axial extension of at least 20% and up to 35% of half the footprint width of the tire. A tire according to any one of claims 1 to 10.

12. The separation between the two parts, the leading edge and the trailing edge, Recesses at the edges of adjacent parts, The inclination angle of each edge of the tire fluctuation with respect to the circumferential direction, The direction or magnitude of the curvature of each of the aforementioned edges, Gradual increase or decrease in chamfer width, A groove extending substantially circumferentially through the aforementioned block, or These combinations A tire according to any one of claims 1 to 11, defined by any one of the following.

13. The tire according to any one of claims 1 to 12, further comprising a second groove extending through each of the set of continuous blocks and connecting two consecutive first grooves.

14. The aforementioned tread, The edge component EI, which corresponds to the ratio between the sum of the projected lengths of the plurality of sipes in the axial direction (SAP) and the circumference C of the tread, [Math 1] The formula is defined such that, in the formula, EI is at least 2 and at most 20, and there are multiple sipes A tire according to any one of claims 1 to 13, further comprising the above.

15. The tire according to any one of claims 1 to 14, wherein the ratio of the void volume to the 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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