tire

Abstract

To improve wet performance while maintaining rolling resistance performance.SOLUTION: A tire 1 includes a tread part 2 formed with a grooved sipe 3. The grooved sipe 3 includes a first grooved sipe 3A and a second grooved sipe 3B. A distance h1 from a tread ground contact surface 2 s to an outer end position 6a in a tire radial direction of a first width-extended groove part 5A of the first grooved sipe 3A is different from a distance h2 from the tread ground contact surface 2 s to an outer end position 6b in a tire radial direction of a second width-extended groove part 5B of the second grooved sipe 3B.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to tires. [Background technology]

[0002] Patent Document 1 below describes a tire having hexagonal blocks formed in the tread portion. The hexagonal blocks are provided with second sipes that cross the hexagonal blocks in the tire axial direction. The second sipes are three-dimensional sipes. Such a tire has reduced rolling resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-104411 Summary of the Invention [Problem to be solved by the invention]

[0004] The tire of Patent Document 1 has room for further improvement in wet performance.

[0005] The present disclosure has been devised in view of the above circumstances, and has as its main object to provide a tire that can improve wet performance while maintaining rolling resistance performance. [Means for solving the problem]

[0006] The present disclosure relates to a tire having a tread portion, wherein a plurality of grooved sipes are formed in the tread portion, the grooved sipes opening at the tread contact surface and extending in the tire axial direction, the plurality of grooved sipes including first grooved sipes and second grooved sipes, the first grooved sipes including a first sipe portion and a first widened groove portion connected to the radially inner side of the first sipe portion and having a width greater than that of the first sipe portion, the second grooved sipes including a second sipe portion and a second widened groove portion connected to the radially inner side of the second sipe portion and having a width greater than that of the second sipe portion, and a distance h1 from the tread contact surface to the radially outer end position of the first widened groove portion is different from a distance h2 from the tread contact surface to the radially outer end position of the second widened groove portion. [Effects of the Invention]

[0007] By employing the above configuration, the tire of the present disclosure can improve wet performance while maintaining rolling resistance performance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view for conceptually explaining an embodiment of a tread portion of the present disclosure. [Figure 2] 1(a) is a cross-sectional view of a first grooved sipe, and FIG. 1(b) is a cross-sectional view of a second grooved sipe. [Figure 3] FIG. [Figure 4] FIG. 4 is a cross-sectional view of a crown circumferential groove. [Figure 5] FIG. [Figure 6] (a) is a plan view of the middle block, and (b) is a cross-sectional view taken along line AA in (a). [Figure 7] FIG. 10 is a plan view of a tread portion of another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. 1 is a plan view for conceptually explaining a tread portion 2 of a tire 1 according to the present disclosure. The tire 1 according to the present disclosure is used, for example, as a pneumatic tire for heavy loads. However, the tire 1 according to the present disclosure may also be used, for example, as a pneumatic tire for passenger cars or motorcycles, or as a non-pneumatic tire that is not filled with compressed air.

[0010] As shown in Fig. 1, the tread portion 2 of this embodiment is formed with a plurality of grooved sipes 3 that open at a tread contact surface 2s and extend in the tire axial direction. The tread contact surface 2s is the surface that comes into contact with a flat surface when a tire 1 in a normal state is placed in contact with the flat surface with a normal load and a camber angle of 0 degrees. Unless otherwise specified, the dimensions of each part of the tire 1 are values ​​measured in a normal state. The "normal state" refers to a state in which the tire 1 is mounted on a normal rim (not shown), inflated to a normal internal pressure, and no load is applied.

[0011] A "genuine rim" is a rim that is defined for each tire by a standard system that includes the standard on which tire 1 is based, such as a "standard rim" for JATMA, a "design rim" for TRA, or a "measuring rim" for ETRTO.

[0012] "Normal internal pressure" is the air pressure specified for each tire by each standard in the standard system, including the standard on which tire 1 is based. In the case of JATMA, it is the "maximum air pressure," in the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and in the case of ETRTO, it is the "INFLATION PRESSURE."

[0013] "Normal load" is the load specified for each tire by each standard in the standard system including the standard on which tire 1 is based, and is the "maximum load capacity" in the case of JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the case of TRA, and the "LOAD CAPACITY" in the case of ETRTO.

[0014] The plurality of grooved sipes 3 include first grooved sipes 3A and second grooved sipes 3B.

[0015] FIG. 2(a) is a cross-sectional view of a first grooved sipe 3A. FIG. 2(b) is a cross-sectional view of a second grooved sipe 3B. As shown in FIG. 2, the first grooved sipe 3A includes a first sipe portion 4A and a first widened groove portion 5A that is continuous with the first sipe portion 4A on the radially inner side and has a width greater than that of the first sipe portion 4A. The second grooved sipe 3B includes a second sipe portion 4B and a second widened groove portion 5B that is continuous with the second sipe portion 4B on the radially inner side and has a width greater than that of the second sipe portion 4B. Such a grooved sipe 3 can discharge a large amount of water on the tread contact surface 2s through the first widened groove portion 5A and the second widened groove portion 5B, thereby improving wet performance.

[0016] The distance h1 from the tread contact surface 2s to the radially outer end position 6a of the first widened groove portion 5A is different from the distance h2 from the tread contact surface 2s to the radially outer end position 6b of the second widened groove portion 5B. As a result, even if wear progresses, the first widened groove portion 5A and the second widened groove portion 5B will not appear at the tread contact surface 2s at the same time, which prevents a significant decrease in rigidity of the tread portion 2 and maintains rolling resistance performance.

[0017] As shown in FIG. 1 , the grooved sipe 3 of this embodiment includes a sipe portion 4 and a widened groove portion 5 that is connected to the radially inward side of the sipe portion 4 and has a width greater than that of the sipe portion 4. Such a grooved sipe 3 can improve wet performance by the widened groove portion 5. Furthermore, by varying the radial distance from the tread contact surface 2s to the widened groove portion 5, rolling resistance performance can be improved. In this specification, the sipe portion 4 and sipes described later refer to notches with a width of less than 1.5 mm. Furthermore, the widened groove portion 5 and grooves described later refer to grooves with a width of 1.5 mm or more.

[0018] The tread portion 2 includes, for example, a first land portion 7A and a second land portion 7B that is disposed at a different position in the tire axial direction from the first land portion 7A. The first land portion 7A has a first grooved sipe 3A formed therein, and the second land portion 7B has a second grooved sipe 3B formed therein. This makes it possible to suppress a significant decrease in rigidity of the first land portion 7A and the second land portion 7B, which are subjected to different ground contact pressures.

[0019] The first land portion 7A and the second land portion 7B may each be formed as a rib-like body extending continuously in the tire circumferential direction, or as a block row in which a plurality of blocks are lined up in the tire circumferential direction (not shown). Each of the first land portion 7A and the second land portion 7B is provided with one first grooved sipe 3A or one second grooved sipe 3B. Each of the first land portion 7A and the second land portion 7B may also be provided with a plurality of first grooved sipes 3A or two second grooved sipes 3B.

[0020] Fig. 3 is a plan view of the tread portion 2 of this embodiment. As shown in Fig. 3, the tread portion 2 includes, for example, a plurality of circumferential grooves 8 extending continuously in the tire circumferential direction and land portions 10 separated by the circumferential grooves 8.

[0021] The circumferential grooves 8 of this embodiment include a pair of crown circumferential grooves 8A located on both sides of the tire equator C and a pair of shoulder circumferential grooves 8B located axially outward of the crown circumferential grooves 8A. Thus, the land portion 10 of this embodiment includes a crown land portion 11, a pair of middle land portions 12 adjacent to both axial sides of the crown land portion 11, and a pair of shoulder land portions 13 adjacent to the axially outward sides of the middle land portions 12. In this embodiment, the crown land portion 11 is located closest to the tire equator C among the land portions 10, for example, on the tire equator C. Each shoulder land portion 13 has a tread edge Te. The tread edge Te is the axially outermost contact point when a tire 1 in a normal state is placed on a flat surface with a normal load and a camber angle of 0 degrees. The axial distance between the tread edges Te is the tread width TW.

[0022] Each of the crown circumferential groove 8A and the shoulder circumferential groove 8B extends in a zigzag manner in the tire circumferential direction to form a zigzag apex K. The apex K includes an outward apex K1 that protrudes outward in the tire axial direction and an inward apex K2 that protrudes inward in the tire axial direction. However, the crown circumferential groove 8A and the shoulder circumferential groove 8B are not limited to this form, and may extend linearly or wavy.

[0023] The groove width W1 of the crown circumferential groove 8A is preferably smaller than the groove width W2 of the shoulder circumferential groove 8B. As a result, the crown land portion 11 and the middle land portion 12 support each other due to deformation of the land portions 11, 12 during rolling of the tire 1, and the apparent rigidity of the crown land portion 11, which is subjected to a large ground contact pressure, is increased, thereby improving rolling resistance performance. To effectively exert the above-mentioned effect, the groove width W1 of the crown circumferential groove 8A is preferably 1% or more of the groove width W2 of the shoulder circumferential groove 8B, more preferably 5% or more, more preferably 20% or less, and even more preferably 15% or less. Furthermore, the groove width W2 of the shoulder circumferential groove 8B is preferably 3% or more of the tread width TW, more preferably 4% or more, more preferably 7% or less, and even more preferably 6% or less. The groove width W1 of the crown circumferential groove 8A and the groove width W2 of the shoulder circumferential groove 8B are measured at the tread contact surface 2s.

[0024] The crown circumferential groove 8A includes a first portion 14A and a second portion 14B having a groove width at the tread contact surface 2s that is larger than that of the first portion 14A. The second portion 14B is formed, for example, between the outward crest K1 and the inward crest K2 and terminates without connecting to the outward crest K1 or the inward crest K2. Although not particularly limited, the tire circumferential length L1 of the second portion 14B is preferably 5% or more of the tread width TW, more preferably 7% or more, more preferably 15% or less, and even more preferably 12% or less. The second portion 14B can be disposed at any position.

[0025] FIG. 4(a) is a cross-sectional view taken along line AA in FIG. 3 and is a transverse cross-sectional view of the first portion 14A. As shown in FIG. 4(a), the first portion 14A includes, for example, an outer portion 15 and an inner portion 16. In this embodiment, the outer portion 15 extends radially inward from the tread contact surface 2s. In this embodiment, the groove width of the outer portion 15 gradually decreases toward the radially inward side of the tire. In this embodiment, the inner portion 16 includes a widened portion 16a that is continuous with the radially inward side of the outer portion 15 and whose groove width gradually increases toward the radially inward side of the tire. The inner portion 16 includes, for example, a narrowed portion 16b that is continuous with the radially inward side of the widened portion 16a and whose groove width gradually decreases toward the radially inward side of the tire.

[0026] The maximum groove width Wi of the inner portion 16 is formed larger than the maximum groove width Ws of the outer portion 15. Such a first portion 14A improves wet performance while also improving rolling resistance performance in the portion where the groove width is smallest. The maximum groove width Ws of the outer portion 15 is the groove width W1 of the crown circumferential groove 8A. In other words, the maximum groove width Ws of the outer portion 15 is formed at the tread contact surface 2s. The maximum groove width Wi of the inner portion 16 is formed at the boundary between the widened portion 16a and the narrowed portion 16b.

[0027] In this embodiment, the length Ds of the outer portion 15 in the tire radial direction is smaller than the length Di of the inner portion 16 in the tire radial direction. The length Ds of the outer portion 15 is preferably 20% or more of the length Di of the inner portion 16, more preferably 25% or more, and more preferably 40% or less, and even more preferably 35% or less.

[0028] Although not particularly limited, the minimum groove width Wc of the crown circumferential groove 8A is, for example, 1.0 to 1.5 mm. The minimum groove width Wc is formed at the boundary position between the widened portion 16a and the outer portion 15. The minimum groove width Wc is preferably 10% or more of the maximum groove width Ws of the outer portion 15, more preferably 15% or more, and more preferably 30% or less, and even more preferably 25% or less.

[0029] 4(b) is a cross-sectional view taken along line BB in FIG. 3 and is a transverse cross-sectional view of the second portion 14B. As shown in FIG. 4(b), the second portion 14B is formed by a constant width portion 17 that extends radially inward from the tread contact surface 2s with the same groove width, and a second narrowing portion 18 that is disposed between the constant width portion 17 and the groove bottom s and whose groove width decreases radially inward. The radial length Dp of the constant width portion 17 is preferably 80% or more of the groove depth D of the second portion 14B, and more preferably 85% or more. The groove width Wp of the constant width portion 17 is, for example, the same as the maximum groove width Wi of the inner portion 16. The groove depth D of the second portion 14B is the same as the groove depth (Di+Ds) of the first portion 14A.

[0030] As shown in FIG. 4(a), the groove bottom s of the crown circumferential groove 8A is provided with a groove bottom ridge 19, which is a raised portion of the groove bottom. The groove bottom ridge 19 prevents small stones or the like from becoming trapped in the crown circumferential groove 8A when the inner portion 16 becomes exposed due to wear, thereby improving wet performance. The width wg of the groove bottom ridge 19 is preferably 0.1 times or more, more preferably 0.2 times or more, more preferably 0.5 times or less, and even more preferably 0.4 times or less of the maximum groove width Wi of the inner portion 16. The raised height hg of the groove bottom ridge 19 is preferably 0.1 times or more, more preferably 0.2 times or more, more preferably 0.5 times or less, and even more preferably 0.4 times or less of the length Di of the inner portion 16.

[0031] Fig. 5 is a plan view of the tread portion 2. As shown in Fig. 5, the crown land portion 11 of this embodiment is divided into crown blocks 11R by a plurality of crown lateral grooves 20 crossing the crown land portion 11. The middle land portion 12 of this embodiment is divided into middle blocks 12R by a plurality of middle lateral grooves 21 crossing the middle land portion 12. The shoulder land portion 13 of this embodiment is divided into shoulder blocks 13R by a plurality of shoulder lateral grooves 22 crossing the shoulder land portion 13.

[0032] The crown lateral grooves 20 connect, for example, a pair of crown circumferential grooves 8A. In this embodiment, the crown lateral grooves 20 connect the inward crests K2 of the crown circumferential grooves 8A. The crown lateral grooves 20 extend, for example, linearly. As a result, the crown block 11R is formed in a barrel-shaped hexagonal shape with the circumferential center portion of the crown block 11R bulging out toward both sides in the axial direction in a plan view of the tread portion.

[0033] The middle lateral grooves 21 connect, for example, the crown circumferential groove 8A and the shoulder circumferential groove 8B. In this embodiment, the middle lateral grooves 21 connect the outward apex K1 of the crown circumferential groove 8A and the inward apex K2 of the shoulder circumferential groove 8B. The middle lateral grooves 21 extend, for example, in a straight line. As a result, the middle blocks 12R are formed in a barrel-shaped hexagonal shape with the circumferential center of the tire bulging outward on both sides in the axial direction in a plan view of the tread portion.

[0034] The shoulder lateral grooves 22 connect, for example, the shoulder circumferential grooves 8B and the tread edge Te. In this embodiment, the shoulder lateral grooves 22 connect to the outward apexes K1 of the shoulder circumferential grooves 8B. The shoulder lateral grooves 22 extend, for example, linearly. As a result, the shoulder blocks 13R are formed in a pentagonal shape with the circumferential center portion bulging axially inward in a tread plan view.

[0035] In this embodiment, first grooved sipes 3A are formed in the crown land portion 11. In this embodiment, second grooved sipes 3B are formed in the middle land portion 12. In other words, the first land portion 7A is the crown land portion 11, and the second land portion 7B is the middle land portion 12. During straight driving, the crown land portion 11 is subjected to greater ground pressure than the middle land portion 12. The distance h1 (shown in FIG. 2) of the first grooved sipes 3A is greater than the distance h2 of the second grooved sipes 3B. This prevents a decrease in rigidity of the crown land portion 11, which is subjected to greater ground pressure, thereby further improving rolling resistance performance. Note that no grooved sipes are formed in the shoulder land portions 13 in this embodiment.

[0036] If the distance h1 is excessively greater than the distance h2, there is a risk that the wet performance will deteriorate. Therefore, the distance h1 is preferably 105% or more of the distance h2, more preferably 110% or more, and is preferably 130% or less, and even more preferably 125% or less. The distance h1 is preferably 4.5 to 10.5 mm, for example.

[0037] As shown in FIG. 2 , in this embodiment, the radial length d1 of the first widened groove portion 5A is smaller than the radial length d2 of the second widened groove portion 5B. This prevents the first grooved sipe 3A and the second grooved sipe 3B from excessively reducing the rigidity of the land portion 10, thereby maintaining high rolling resistance. Furthermore, the ratio (d1 / Di) of the length d1 of the first widened groove portion 5A to the length Di of the inner portion 16 of the crown circumferential groove 8A is preferably 0.30 or more, more preferably 0.35 or more, more preferably 0.50 or less, and even more preferably 0.45 or less. Furthermore, the ratio (d2 / Di) of the length d2 of the second widened groove portion 5B to the length Di of the inner portion 16 is preferably 0.4 or more, more preferably 0.45 or more, more preferably 0.6 or less, and even more preferably 0.55 or less. The length d1 of the first widened groove portion 5A is preferably, for example, 4.5 to 10.5 mm.

[0038] The absolute value |D1-D2| of the difference between the depth D1 of the first grooved sipe 3A and the depth D2 of the second grooved sipe 3B is, for example, preferably 3 mm or less, more preferably 2 mm or less, and even more preferably 1 mm or less. In this embodiment, the depth D1 of the first grooved sipe 3A is the same as the depth D2 of the second grooved sipe 3B.

[0039] As shown in FIGS. 1 and 2, in this embodiment, the sipe portion 4 extends in a zigzag pattern in the longitudinal direction. Furthermore, the sipe portion 4 extends in a zigzag pattern in the tire radial direction, for example. In this manner, the sipe portion 4 is formed as a so-called three-dimensional sipe. Since both wall surfaces 4s of the sipe portion 4 are formed with repeated concaves and convexes, they tightly mesh with each other when the tire 1 rolls. Therefore, the apparent rigidity of the tread portion 2 in which the grooved sipes 3 are formed is increased, suppressing collapse and deformation of the tread portion 2, thereby further improving rolling resistance performance.

[0040] In a plan view of the tread, the sipe portion 4 includes a first portion 4a inclined to one side with respect to the longitudinal direction and a second portion 4b inclined to the opposite side from the first portion 4a. The angle θ1 between the first portion 4a and the second portion 4b is preferably 100 degrees or more, more preferably 105 degrees or more, and is preferably 125 degrees or less, and even more preferably 120 degrees or less. Such a sipe portion 4 can effectively exert the above-mentioned effects.

[0041] 2, in a cross-sectional view of the grooved sipe 3, the sipe portion 4 includes a first portion 4c inclined to one side with respect to the tire radial direction and a second portion 4d inclined to the opposite side from the first portion 4c. The angle θ2 between the first portion 4c and the second portion 4d is preferably 100 degrees or more, more preferably 105 degrees or more, and is preferably 125 degrees or less, and even more preferably 120 degrees or less.

[0042] In this embodiment, the widened groove portion 5 has an elliptical cross section. The widened groove portion 5 is formed, for example, as a vertically elongated ellipse with the major axis in the tire radial direction. Such widened groove portion 5 suppresses a decrease in the rigidity of the tread portion 2 in the tire radial direction, thereby maintaining high rolling resistance performance. To effectively exert this effect, the ratio (w / d) of the length d to the width w in the tire radial direction of the widened groove portion 5 is preferably 0.4 or more, more preferably 0.45 or more, more preferably 0.6 or less, and even more preferably 0.55 or less.

[0043] Although not particularly limited, the ratio (d / da) of the depth da of the sipe portion 4 to the depth d of the widened groove portion 5 is preferably 0.25 or more, more preferably 0.3 or more, and is preferably 0.45 or less, and even more preferably 0.4 or less.

[0044] As shown in FIG. 5, in this embodiment, one first grooved sipe 3A is formed in the crown block 11R. The first grooved sipe 3A connects, for example, the outward apexes K1 of the crown circumferential grooves 8A. In this embodiment, one second grooved sipe 3B is formed in the middle block 12R. The second grooved sipe 3B connects, for example, the inward apex K2 of the crown circumferential groove 8A and the outward apex K1 of the shoulder circumferential groove 8B. Note that a plurality of first grooved sipes 3A may be formed in the crown block 11R. Also, a plurality of second grooved sipes 3B may be formed in the middle block 12R.

[0045] The second grooved sipes 3B of this embodiment overlap in the tire circumferential direction with the crown lateral grooves 20. For example, the openings 27a of the second grooved sipes 3B in the crown circumferential grooves 8A are in the same positions in the tire circumferential direction as the openings 27b of the crown circumferential grooves 8A of the crown lateral grooves 20. This allows water in the crown lateral grooves 20 to flow through the second grooved sipes 3B to the shoulder circumferential grooves 8B, improving wet performance.

[0046] Each of the crown blocks 11R, middle blocks 12R, and shoulder blocks 13R has a vertically elongated shape in which the maximum circumferential length Ls is greater than the maximum axial length Lj. These blocks 11R-13R have high circumferential rigidity and excellent rolling resistance. If the circumferential maximum length Ls of each block 11R-13R is excessively greater than the axial maximum length Lj, the axial rigidity may be reduced. Therefore, the ratio (Ls / Lj) of the circumferential maximum length Ls to the axial maximum length Lj is preferably 1.2 or greater, more preferably 1.3 or greater, and more preferably 1.8 or less, and even more preferably 1.7 or less.

[0047] FIG. 6(a) is a plan view of the middle block 12R. FIG. 6(b) is a cross-sectional view taken along line AA in FIG. 6(a). FIG. 6(b) shows a cross section of the middle block 12R parallel to the tire circumferential direction. As shown in FIG. 6, the middle block 12R of this embodiment has an end portion 12A including one end 12e in the tire circumferential direction. The end portion 12A is provided with, for example, an inclined surface 25 that slopes continuously radially inward from the inner side of the middle block 12R in the tire circumferential direction to the one end 12e. Such an inclined surface 25 allows water on the tread contact surface 2s of the middle block 12R to be smoothly discharged into the middle lateral grooves 21.

[0048] The circumferential length La of the inclined surface 25 is preferably at least 0.1 times the maximum circumferential length Ls of the middle block 12R, more preferably at least 0.15 times, preferably at most 0.25 times, and more preferably at most 0.20 times. The radial length ha of the inclined surface 25 is preferably at least 0.1 times the radial maximum height Hm of the middle block 12R, more preferably at least 0.2 times, preferably at most 0.5 times, and more preferably at most 0.4 times.

[0049] FIG. 7 is a plan view of a tread portion 2 of another embodiment. The same components as those in the tread portion 2 of this embodiment are assigned the same reference numerals, and detailed descriptions thereof will be omitted. The tread portion 2 of this embodiment is provided with a first land portion 7A. The first land portion 7A of this embodiment is provided with a first grooved sipe 3A and a second grooved sipe 3B. In this embodiment, the first land portion 7A is a crown land portion 11. The crown land portion 11 is a land portion that receives a relatively large ground contact pressure during straight running. By providing the first grooved sipe 3A and the second grooved sipe 3B in this crown land portion 11, the appearance of each widened groove portion 5 within the crown land portion 11 differs, improving rolling resistance performance.

[0050] The first land portion 7A includes first blocks 7e and second blocks 7i arranged in the tire circumferential direction. In this embodiment, the first blocks 7e are formed with first grooved sipes 3A. The second blocks 7i are formed with, for example, second grooved sipes 3B. The first land portion 7A may also be formed with third grooved sipes (not shown) having sipe portions 4 and widened groove portions 5. The distance from the tread contact surface 2s to the radially outer end position of the widened groove portion 5 of the third grooved sipe is different from the distance h1 of the first grooved sipe 3A and the distance h2 of the second grooved sipe 3B.

[0051] The tread portion 2 of this embodiment is also provided with a second land portion 7B. The second land portion 7B is, for example, a middle land portion 12. The second land portion 7B includes first blocks 7j and second blocks 7k arranged in the tire circumferential direction. In this embodiment, the first blocks 7j are formed with first grooved sipes 3A. The second blocks 7k are formed with, for example, second grooved sipes 3B.

[0052] Although a tire according to one embodiment of the present disclosure has been described in detail above, the present disclosure is not limited to the above-described specific embodiment and can be modified and implemented in various aspects. [Example]

[0053] Heavy-duty tires having the basic pattern shown in Figure 3 were prototyped based on the specifications in Table 1, and the rolling resistance and wet performance of each sample tire were tested. The test method and common specifications are as follows: Tire size: 315 / 70R22.5 Rim size: 22.5 x 9.00 Internal pressure: 900kPa D1, D2: 15mm Di: Same (Note that Di in Example 6 is the same as Di in Example 1)

[0054] <Rolling resistance performance> Using a rolling resistance tester, the rolling resistance of the sample tires was measured under the following conditions in accordance with ISO 28580. The results are expressed as an index, with the reciprocal of the value of Comparative Example 1 set to 100. The larger the index, the better the rolling resistance performance. Load: 31.25kN Speed: 80km / h

[0055] <Wet performance> Using the test vehicle below, a wet performance (wet braking performance) test was conducted in accordance with R117-02 (ECE Regulation No. 117 Revision 2). For this wet performance test, the braking distance from the start of braking at a specified initial speed to the vehicle coming to a complete stop was measured on a water-sprayed road surface. The results are expressed as an index, with the reciprocal of the braking distance of Comparative Example 1 set to 100. The larger the index, the better the wet performance. Test vehicle: 10-ton truck (2-D vehicle) Load capacity: 75% of standard load capacity Wet road surface: Water depth 0.5 to 2 mm Speed: 65km / h The test results are shown in Table 1.

[0056] [Table 1]

[0057] As a result of the test, it was confirmed that the tires of the examples had improved wet performance while maintaining rolling resistance performance.

[0058] [Note] The present disclosure includes the following aspects.

[0059] [Disclosure 1] A tire having a tread portion, The tread portion has a plurality of grooved sipes formed therein, the grooved sipes opening at the tread contact surface and extending in the tire axial direction, The plurality of grooved sipes include a first grooved sipe and a second grooved sipe, The first grooved sipe includes a first sipe portion and a first widened groove portion that is continuous with the first sipe portion on the inner side in the tire radial direction and has a width larger than that of the first sipe portion, The second grooved sipe includes a second sipe portion and a second widened groove portion that is continuous with the second sipe portion on the inner side in the tire radial direction and has a width larger than that of the second sipe portion, a distance h1 from the tread ground contact surface to the outer end position of the first widened groove portion in the tire radial direction is different from a distance h2 from the tread ground contact surface to the outer end position of the second widened groove portion in the tire radial direction; tire. [Disclosure 2] the tread portion includes a first land portion and a second land portion disposed at a position different from that of the first land portion in the tire axial direction, The first grooved sipe is formed in the first land portion, The tire according to Disclosure 1, wherein the second grooved sipes are formed in the second land portions. [Disclosure 3] the first land portion is a crown land portion located closest to the tire equator among the land portions, The tire according to Disclosure 2, wherein the second land portion is a middle land portion adjacent to the crown land portion. [Disclosure 4] The tire according to any one of Disclosures 1 to 3, wherein the distance h1 is greater than the distance h2. [Disclosure 5] The tire according to Disclosure 4, wherein the distance h1 is 110% to 150% of the distance h2. [Disclosure 6] The tread portion includes a crown land portion located closest to the tire equator among the land portions, a middle land portion adjacent to the crown land portion, a crown circumferential groove separating the crown land portion from the middle land portion, and a shoulder circumferential groove disposed axially outward of the middle land portion, The tire according to any one of Disclosures 1 to 5, wherein the groove width of the crown circumferential groove is smaller than the groove width of the shoulder circumferential groove. [Disclosure 7] The tire described in Disclosure 6, wherein the crown circumferential groove includes an outer portion extending radially inward from the tread contact surface, and an inner portion continuing to the radially inward of the outer portion and including a widening portion in which the groove width gradually increases toward the radially inward of the tire. [Disclosure 8] The tire according to Disclosure 7, wherein the outer portion has a groove width that gradually decreases toward the inside in the tire radial direction. [Disclosure 9] The tire according to Disclosure 7 or 8, wherein the maximum groove width of the outer portion is the same as the maximum groove width of the inner portion. [Disclosure 10] The tire according to any one of Disclosures 7 to 9, wherein the inner portion includes a narrowed portion that is continuous with the widened portion on the inner side in the tire radial direction and in which the groove width gradually decreases toward the inner side in the tire radial direction. [Disclosure 11] The middle land portion is divided into middle blocks by a plurality of middle lateral grooves that cross the middle land portion, The middle block has an end portion including one end in the tire circumferential direction, The tire according to any one of claims 6 to 10, wherein the end portion is provided with an inclined surface that slopes continuously inward in the tire radial direction from the inner side in the tire circumferential direction of the middle block to the one end. [Disclosure 12] The tread portion includes a first land portion, The tire according to Disclosure 1, wherein the first grooved sipes and the second grooved sipes are formed in the first land portion. [Disclosure 13] the first land portion includes first blocks and second blocks arranged in the tire circumferential direction, The first block has the first grooved sipe formed therein, The tire according to the present disclosure 12, wherein the second grooved sipe is formed in the second block. [Explanation of symbols]

[0060] 1 tire 2 Tread section 2s tread contact surface 3 Grooved sipes 3A First grooved sipe 3B Second grooved sipe 5A First widening groove 5B Second widening groove 6a Outer end position 6b Outer end position

Claims

1. A tire having a tread portion, The tread portion has a plurality of grooved sipes formed therein, the grooved sipes opening at the tread contact surface and extending in the tire axial direction, The plurality of grooved sipes include a first grooved sipe and a second grooved sipe, The first grooved sipe includes a first sipe portion and a first widened groove portion that is continuous with the first sipe portion on the inner side in the tire radial direction and has a width larger than that of the first sipe portion, The second grooved sipe includes a second sipe portion and a second widened groove portion that is continuous with the second sipe portion on the inner side in the tire radial direction and has a width larger than that of the second sipe portion, a distance h1 from the tread ground contact surface to a radially outer end position of the first widened groove portion is different from a distance h2 from the tread ground contact surface to a radially outer end position of the second widened groove portion, the tread portion includes a first land portion, The first land portion has the first grooved sipe and the second grooved sipe formed therein, the first land portion includes first blocks and second blocks arranged in the tire circumferential direction, Only the first grooved sipe is formed in the first block, Only the second grooved sipe is formed in the second block, The first land portion is a crown land portion located closest to the tire equator among the land portions. tire.

2. A tire having a tread portion, The tread portion has a plurality of grooved sipes formed therein, the grooved sipes opening at the tread contact surface and extending in the tire axial direction, The plurality of grooved sipes include a first grooved sipe and a second grooved sipe, The first grooved sipe includes a first sipe portion and a first widened groove portion that is continuous with the first sipe portion on the inner side in the tire radial direction and has a width larger than that of the first sipe portion, The second grooved sipe includes a second sipe portion and a second widened groove portion that is continuous with the second sipe portion on the inner side in the tire radial direction and has a width larger than that of the second sipe portion, a distance h1 from the tread ground contact surface to a radially outer end position of the first widened groove portion is different from a distance h2 from the tread ground contact surface to a radially outer end position of the second widened groove portion, The tread portion is provided with a second land portion, The first grooved sipe and the second grooved sipe are formed in the second land portion, the second land portion includes first blocks and second blocks arranged in the tire circumferential direction, Only the first grooved sipe is formed in the first block, Only the second grooved sipe is formed in the second block, The second land portion is a middle land portion adjacent to the crown land portion located closest to the tire equator among the land portions. tire.

3. The tread portion includes a second land portion arranged at a different position in the tire axial direction from the first land portion, The tire according to claim 1 , wherein the second grooved sipe is formed in the second land portion.

4. The tread portion includes a first land portion arranged at a different position in the tire axial direction from the second land portion, The tire according to claim 2 , wherein the first grooved sipe is formed in the first land portion.

5. A tire described in any one of claims 1 to 4, wherein the distance h1 is greater than the distance h2.

6. A tire as described in claim 5, wherein the distance h1 is 110% to 150% of the distance h2.

7. The tread portion includes a crown land portion located closest to the tire equator among the land portions, a middle land portion adjacent to the crown land portion, a crown circumferential groove separating the crown land portion from the middle land portion, and a shoulder circumferential groove arranged outside the middle land portion in the tire axial direction, The tire according to claim 1 , wherein a groove width of the crown circumferential groove is smaller than a groove width of the shoulder circumferential groove.

8. A tire as described in claim 7, wherein the crown circumferential groove includes an outer portion extending radially inward from the tread contact surface, and an inner portion that is connected to the radially inward side of the outer portion and includes a widening portion in which the groove width gradually increases toward the radially inward side of the tire.

9. A tire as described in claim 8, wherein the groove width of the outer portion gradually decreases toward the inside in the tire radial direction.

10. A tire as described in claim 8 or 9, wherein the maximum groove width of the outer portion is the same as the maximum groove width of the inner portion.

11. A tire as described in any one of claims 8 to 10, wherein the inner portion includes a narrowed portion that is continuous with the widened portion radially inward of the tire and in which the groove width gradually decreases toward the radially inward side of the tire.

12. The middle land portion is divided into middle blocks by a plurality of middle lateral grooves that cross the middle land portion, The middle block has an end portion including one end in the tire circumferential direction, 12. The tire according to claim 7, wherein the end portion is provided with an inclined surface that slopes continuously radially inward from the inner side of the middle block in the tire circumferential direction to the one end.

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