tire

Abstract

To provide a tire which improves wet performance while maintaining rolling resistance performance.SOLUTION: A tire 1 includes: a zigzag-shaped circumferential groove 3; a plurality of lateral grooves 4 connecting between the tops K of zigzag; and a plurality of hexagonal blocks 5 which is formed by the circumferential groove 3 and the lateral grooves 4. The circumferential groove 3 includes a pair of shoulder circumferential grooves 3A and at least one crown circumferential groove 3B. A groove width W2 of the crown circumferential groove 3B is smaller than a groove width W1 of the shoulder circumferential groove 3A. The hexagonal block 5 is provided with a sipe 6 extending a tire axial direction, and a widened groove part 7 which is continuous with an inner side of the sipe 6 in a tire radial direction, and extends in the tire axial direction with a width wider than the sipe 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 below describes a tire in which hexagonal blocks are formed in the tread portion by a plurality of zigzag circumferential grooves and lateral grooves connecting the zigzag circumferential grooves. The zigzag circumferential grooves include a pair of center circumferential grooves and a pair of shoulder circumferential grooves that are wider than the center circumferential grooves. The hexagonal blocks are provided with second sipes that cross the hexagonal blocks in the tire axial direction. Such a tire is said to have reduced rolling resistance and to suppress cracks at the bottom of the lateral grooves. [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] However, the tire of Patent Document 1 has a problem in that the groove width of the central circumferential groove is small, which deteriorates drainage and reduces 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 the tread portion includes a plurality of circumferential grooves extending in a zigzag pattern in the tire circumferential direction to form zigzag crests, a plurality of lateral grooves connecting the zigzag crests of the circumferential grooves adjacent in the tire axial direction, and a plurality of hexagonal blocks formed by the circumferential grooves and the plurality of lateral grooves, wherein the circumferential grooves include a pair of shoulder circumferential grooves arranged on the tread end sides, and at least one crown circumferential groove arranged axially inward of the pair of shoulder circumferential grooves, the groove width of the crown circumferential groove being smaller than the groove width of the pair of shoulder circumferential grooves, and the hexagonal blocks are provided with sipes extending in the tire axial direction, and widened groove portions that are continuous with the sipes radially inward and extend in the tire axial direction with a width larger than that of the sipes. [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] 1 is a plan view of a tread portion showing one embodiment of a tire of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. [Figure 4] FIG. 2 is a perspective view illustrating an outline of a sipe and an expanded groove portion. [Figure 5] 4A is a cross-sectional view taken along line BB in FIG. 3, and FIG. 4B is a cross-sectional view taken along line CC in FIG. [Figure 6] 4A is a cross-sectional view taken along line DD in FIG. 3, and FIG. 4B is a cross-sectional view taken along line EE in FIG. 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 showing an expanded tread portion 2 of a tire 1 according to the present disclosure. The tire 1 according to the present disclosure is, for example, 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] 1, the tread portion 2 includes a plurality of circumferential grooves 3 extending in a zigzag pattern in the tire circumferential direction to form zigzag peaks K, and a plurality of lateral grooves 4 connecting the zigzag peaks K of adjacent circumferential grooves 3 in the tire axial direction. As a result, the tread portion 2 includes, for example, a plurality of hexagonal blocks 5 formed by the circumferential grooves 3 and the plurality of lateral grooves 4.

[0011] The circumferential grooves 3 include a pair of shoulder circumferential grooves 3A arranged on the tread edge Te side, and at least one crown circumferential groove 3B arranged axially inward of the pair of shoulder circumferential grooves 3A. In this embodiment, the crown circumferential grooves 3B are formed in pairs, each arranged on either side of the tire equator C.

[0012] The "tread edge Te" is the axially outermost contact point when the tire 1 is mounted on a regular rim, inflated to a regular internal pressure, and in a normal unloaded state, is placed on a flat surface with a regular 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 axial distance between both tread edges Te is the tread width TW.

[0013] 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.

[0014] "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."

[0015] "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.

[0016] The groove width W2 of the crown circumferential groove 3B is smaller than the groove width W1 of the shoulder circumferential groove 3A. This maintains a high apparent rigidity of the hexagonal blocks 5 adjacent to the crown circumferential groove 3B, which receives a large ground contact pressure, thereby preventing a decrease in rolling resistance and wear resistance.

[0017] FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. As shown in FIGS. 1 and 2, each hexagonal block 5 is provided with sipes 6 extending in the tire axial direction and widened groove portions 7 that are connected to the sipes 6 radially inward and extend in the tire axial direction with a width Wt greater than that of the sipes 6. The sipes 6 reduce distortion caused by the movement of the entire block, thereby maintaining high rolling resistance and wear resistance. The widened groove portions 7 can also capture water on the tread surface of the block through the sipes 6 and discharge it to the outside of the tread through the circumferential grooves 3. This prevents deterioration of drainage near the tire equator C and improves wet performance. Furthermore, because the widened groove portions 7 are provided radially inward of the sipes 6, wet performance is enhanced until the end of wear. Therefore, the tire 1 of the present disclosure can improve wet performance while maintaining rolling resistance performance.

[0018] In this specification, a "sipe" is a notched recess having a width Ws perpendicular to the longitudinal direction of the tire of less than 1.5 mm, and is distinguished from a groove having a width of 1.5 mm or more.

[0019] In this embodiment, the circumferential grooves 3 extend continuously in the tire circumferential direction. Each circumferential groove 3 has a first portion 3s that is continuously inclined toward one side with respect to the tire circumferential direction and a second portion 3t that is continuously inclined in the opposite direction to the first portion 3s, and is formed by alternately arranging the first portion 3s and the second portion 3t. Apexes K are formed at positions where the first portion 3s and the second portion 3t intersect. In each circumferential groove 3, the apexes K include a first apex K1 that is convex toward the tire equator C and a second apex K2 that is convex toward the tread edge Te, and the first apex K1 and the second apex K2 are arranged alternately.

[0020] In each circumferential groove 3, the angle α1 of the first portion 3s and the second portion 3t relative to the tire circumferential direction is preferably 5 degrees or more, more preferably 10 degrees or more, and is preferably 30 degrees or less, and more preferably 25 degrees or less.

[0021] The first portion 3s and the second portion 3t extend, for example, linearly. However, the first portion 3s and the second portion 3t are not limited to this, and may extend, for example, in an arc shape, in other words, each circumferential groove 3 may extend in a wave shape.

[0022] The crown circumferential groove 3B has a pair of groove walls 10e extending in the longitudinal direction. The shoulder circumferential groove 3A also has a pair of groove walls 10i extending in the longitudinal direction. Under a normal load, at least a portion of the pair of groove walls 10e contacts each other. Under a normal load, the pair of groove walls 10i do not contact each other. Due to this contact, the crown circumferential groove 3B has high apparent rigidity and therefore excellent rolling resistance. The shoulder circumferential groove 3A also improves wet performance.

[0023] In order to exert such an effect, the groove width W2 of the crown circumferential groove 3B is preferably 1% or more, more preferably 5% or more, and more preferably 20% or less, and even more preferably 15% or less of the groove width W1 of the shoulder circumferential groove 3A. , 1.5mm or more is desirable, The groove width W1 of the shoulder circumferential groove 3A is not particularly limited, but is preferably 6.0 to 16.0 mm.

[0024] The lateral grooves 4 include, for example, middle lateral grooves 4A, crown lateral grooves 4B, and shoulder lateral grooves 4C. The middle lateral groove 4A connects, for example, the shoulder circumferential groove 3A and the crown circumferential groove 3B. In this embodiment, the middle lateral groove 4A connects the crest K of the shoulder circumferential groove 3A and the crest K of the crown circumferential groove 3B. The crown lateral groove 4B connects, for example, a pair of crown circumferential grooves 3B. In this embodiment, the crown lateral groove 4B connects the crests K of the crown circumferential grooves 3B. The shoulder lateral groove 4C connects, for example, the shoulder circumferential groove 3A and the tread edge Te. In this embodiment, the shoulder lateral groove 4C connects the crest K of the shoulder circumferential groove 3A and the tread edge Te.

[0025] In this embodiment, each lateral groove 4 extends linearly. However, the lateral grooves 4 may extend in an arc-like, wavy, or zigzag pattern. Each lateral groove 4 is inclined relative to the tire axial direction. Such lateral grooves 4 can smoothly drain water from within the grooves by utilizing the rotation of the tire 1. The angle α2 of each lateral groove 4 relative to the tire axial direction is preferably 5 degrees or more, more preferably 10 degrees or more, and preferably 25 degrees or less, and even more preferably 20 degrees or less. The angle α2 of the middle lateral groove 4A, the angle α2 of the crown lateral groove 4B, and the angle α2 of the shoulder lateral groove 4C are the same. In this specification, the term "same angles" includes not only a case where the difference in angle between these lateral grooves 4 is 0 degrees, but also a case where the absolute value of the difference in angle is 5 degrees or less.

[0026] The groove width W3 of each lateral groove 4 is formed to be larger than the groove width W2 of the crown circumferential groove 3B, for example, and smaller than the groove width W1 of the shoulder circumferential groove 3A.

[0027] The groove width W3 of the middle lateral grooves 4A, the groove width W3 of the crown lateral grooves 4B, and the groove width W3 of the shoulder lateral grooves 4C are the same. In this specification, the groove widths being the same not only means that the difference in groove width between these lateral grooves 4 is zero, but also includes a case where the difference in groove width between these lateral grooves 4 is 2 mm or less.

[0028] Fig. 3 is a plan view of the tread portion 2. As shown in Fig. 3, the tread portion 2 of this embodiment includes a plurality of middle blocks 8A, a plurality of crown blocks 8B, and a plurality of shoulder blocks 8C. Each middle block 8A is divided by a shoulder circumferential groove 3A, a crown circumferential groove 3B, and a circumferentially adjacent middle lateral groove 4A. Each crown block 8B is divided by a pair of crown circumferential grooves 3B and a circumferentially adjacent crown lateral groove 4B. Each shoulder block 8C is divided by a tread edge Te, a shoulder circumferential groove 3A, and a circumferentially adjacent shoulder lateral groove 4C.

[0029] In this embodiment, the middle block 8A and the crown block 8B are formed as hexagonal blocks 5. The middle block 8A of this embodiment is provided with sipes 6 and widened groove portions 7. Furthermore, for example, the crown block 8B is also provided with sipes 6 and widened groove portions 7.

[0030] In this specification, the hexagonal blocks 5 refer to barrel-shaped blocks whose axial length LA increases continuously from both circumferential ends of the block toward the center, and which bulge outward in the axial direction. These hexagonal blocks 5 have high axial rigidity and therefore high wear resistance.

[0031] To effectively exert the above-mentioned effect, the ratio (La / Wa) of the circumferential length La of the hexagonal block 5 to the axial width Wa of the hexagonal block 5 is preferably 1.2 or more, more preferably 1.3 or more, and is preferably 1.8 or less, and even more preferably 1.7 or less. The length La and the width Wa are each the maximum value of the hexagonal block 5.

[0032] Both ends of the sipes 6 and the widened groove portions 7 are connected to the circumferential grooves 3. This further improves wet performance. In this embodiment, both ends of the sipes 6 and the widened groove portions 7 are connected to the apex K.

[0033] 2 and 3, the sipes 6 extend, for example, in a zigzag pattern in the sipe longitudinal direction and the tire radial direction. When the tire rotates, the walls of the sipes 6 come into contact with each other and support each other, increasing the apparent block rigidity and improving rolling resistance and wear resistance. This type of sipe 6 is called, for example, a Miura-folded (three-dimensional) sipe.

[0034] The sipes 6 are not limited to this form, and may be, for example, formed to extend linearly in either the sipe longitudinal direction or the tire radial direction, or in both directions.

[0035] The cross-sectional shape of the widened groove portion 7 is circular or elliptical. Such widened groove portion 7 relieves distortion at the bottom of the sipe and suppresses the occurrence of cracks. The widened groove portion 7 extends linearly along the longitudinal direction. Such widened groove portion 7 has low drainage resistance inside, improving wet performance.

[0036] 4 is a perspective view of the sipe 6 and the widened groove portion 7. As shown in FIG. 4, the shape of the joint 9 where the sipe 6 and the widened groove portion 7 are connected extends in a zigzag shape along the longitudinal direction of the widened groove portion 7. Such joint 9 helps to maintain the rigidity of the hexagonal block 5 at an even higher level.

[0037] Although not particularly limited, the width (maximum width) Wt of the widened groove portion 7 is preferably at least 7 times the width Ws of the sipe 6 (the width of the hexagonal block 5 on the tread surface 5a), more preferably at least 8 times, more preferably at most 13 times, and even more preferably at most 12 times. Also, as shown in FIG. 2, the depth dt of the widened groove portion 7 is formed smaller than the depth ds of the sipe 6. This maintains high block rigidity of the hexagonal block 5. The depth dt of the widened groove portion 7 is preferably at least 10% of the depth ds of the sipe 6, more preferably at least 20%, even more preferably at least 25%, preferably at most 50%, more preferably at most 40%, and even more preferably at most 35%. This improves rolling resistance and wet performance in a well-balanced manner. The sipes 6 and the widened groove portion 7 are separated by the outermost end M in the tire radial direction, where the width is 1.5 mm.

[0038] FIG. 5(a) is a cross-sectional view taken along line BB in FIG. 3. FIG. 5(b) is a cross-sectional view taken along line CC in FIG. 3. FIG. 5(a) shows the cross-sectional area S2 of the crown lateral groove 4B. FIG. 5(b) shows the cross-sectional area S1 of the widened groove portion 7 of the middle block 8A. The cross-sectional area S1 of the widened groove portion 7 of the middle block 8A is preferably 10% or more of the cross-sectional area S2 of the crown lateral groove 4B, more preferably 20% or more, more preferably 40% or less, and even more preferably 30% or less. Because the cross-sectional area S1 of the widened groove portion 7 of the middle block 8A is 10% or more of the cross-sectional area S2 of the crown lateral groove 4B, smooth drainage is achieved by the widened groove portion 7. Because the cross-sectional area S1 of the widened groove portion 7 of the middle block 8A is 40% or less of the cross-sectional area S2 of the crown lateral groove 4B, high rigidity of the middle block 8A is maintained.

[0039] To achieve the same effect, the cross-sectional area of ​​the widened groove portion 7 of the crown block 8B is preferably 10% or more of the cross-sectional area of ​​the middle lateral groove 4A, more preferably 20% or more, more preferably 40% or less, and even more preferably 30% or less (not shown).

[0040] Figure 6(a) is a cross-sectional view taken along line DD in Figure 3. Figure 6(a) shows the middle block 8A as viewed axially from the crown lateral groove 4B. As shown in Figures 6(a) and 3, the axially inner end 7i of the widened groove portion 7 of the middle block 8A overlaps in the tire circumferential direction with the intersection P1 between the crown lateral groove 4B and the crown circumferential groove 3B. This allows water in the crown lateral groove 4B to be discharged to the outside of the tread portion 2 via the crown circumferential groove 3B or the widened groove portion 7 of the middle block 8A, improving wet performance.

[0041] In this embodiment, 80% or more of the cross-sectional area S1 of the widened groove portion 7 of the middle block 8A overlaps in the tire circumferential direction with the intersection point P1 where the crown lateral groove 4B and the crown circumferential groove 3B intersect. This effectively exerts the above-mentioned effect. In Figure 6(a), the cross-sectional area S3 of the overlapping portion Q1 where the widened groove portion 7 of the middle block 8A overlaps in the tire circumferential direction with the intersection point P1 is shown by hatching.

[0042] An axially outer end 7e of the widened groove portion 7 of the middle block 8A overlaps in the tire circumferential direction with an intersection P2 between the shoulder lateral groove 4C and the shoulder circumferential groove 3A.

[0043] Figure 6(b) is a cross-sectional view taken along line EE in Figure 3. Figure 6(b) shows the crown block 8B as viewed axially from the middle lateral groove 4A. As shown in Figures 6(b) and 3, both axial ends 7j of the widened groove portion 7 of the crown block 8B overlap in the tire circumferential direction with the intersection P3 between the middle lateral groove 4A and the crown circumferential groove 3B. This allows water in the widened groove portion 7 of the crown block 8B to flow smoothly into the crown circumferential groove 3B or the middle lateral groove 4A, improving wet performance.

[0044] In this embodiment, 80% or more of the cross-sectional area of ​​the widened groove portion 7 of the crown block 8B overlaps with the intersection portion P3 where the middle lateral groove 4A and the crown circumferential groove 3B intersect in the tire circumferential direction. This effectively exerts the above-mentioned effect. Figure 6(b) shows the cross-sectional area S6 of the overlap portion Q3 where the widened groove portion 7 of the crown block 8B overlaps with the intersection portion P3 in the tire circumferential direction.

[0045] The shoulder lateral grooves 4C and the shoulder blocks 8C are formed, for example, with a well-known configuration, and therefore detailed description of the shoulder lateral grooves 4C and the shoulder blocks 8C will be omitted.

[0046] 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]

[0047] Heavy-duty tires (315 / 70R22.5) with the basic pattern shown in Figure 1 were prototyped based on the specifications in Table 1, and the rolling resistance, wet performance, and wear resistance of each prototype tire were tested. The test methods and common specifications are as follows: Rim size: 22.5 x 9.00 Internal pressure: 900kPa

[0048] <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 in Example 1 set to 100. The larger the index, the better the rolling resistance performance. Load: 25.01kN Speed: 80km / h

[0049] <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 in Example 1 set to 100. The larger the index, the better the wet performance. Test vehicle: 10-ton truck (2-D vehicle) Load: 50% of standard load

[0050] <Wear resistance> Using the above test vehicle, the distance traveled until the circumferential grooves were worn down by 50% was measured. The results are expressed as an index, with the distance traveled in Example 1 being set at 100. The larger the index, the better the wear resistance. The test results are shown in Table 1. In each example, "W1", "S2", and "La" are all the same value, and "W2", "S1", "S3", and "Wa" are varied. In Comparative Example 2, W2 / W1 being 0 means that W2 is 0.3 mm.

[0051] [Table 1]

[0052] As a result of the test, it was confirmed that the tires of the examples had excellent wet performance. In addition, it was confirmed that the tires of the examples maintained high rolling resistance performance and wear resistance performance.

[0053] [Note] The present disclosure includes the following aspects.

[0054] [Disclosure 1] A tire having a tread portion, the tread portion includes a plurality of circumferential grooves extending in a zigzag pattern in the tire circumferential direction so as to form zigzag peaks, a plurality of lateral grooves connecting the zigzag peaks of the circumferential grooves adjacent in the tire axial direction, and a plurality of hexagonal blocks formed by the circumferential grooves and the plurality of lateral grooves, the circumferential grooves include a pair of shoulder circumferential grooves arranged on tread end sides, and at least one crown circumferential groove arranged axially more inward than the pair of shoulder circumferential grooves, a groove width of the crown circumferential groove is smaller than a groove width of the pair of shoulder circumferential grooves, The hexagonal blocks are provided with sipes extending in the tire axial direction, and widened groove portions that are continuous with the sipes on the inner side in the tire radial direction and extend in the tire axial direction with a width larger than that of the sipes. tire. [Disclosure 2] the crown circumferential groove has a pair of groove walls extending in a longitudinal direction, The tire according to Disclosure 1, wherein, under normal load conditions, at least a portion of the pair of groove walls contacts each other. [Disclosure 3] The tire according to Disclosure 1 or 2, wherein the groove width of the crown circumferential groove is 1% to 20% of the groove width of the shoulder circumferential groove. [Disclosure 4] The tire according to any one of Disclosures 1 to 3, wherein the sipes extend in a zigzag pattern in the sipe longitudinal direction and the tire radial direction. [Disclosure 5] The tire according to any one of Disclosures 1 to 4, wherein the cross-sectional shape of the widened groove portion is circular or elliptical. [Disclosure 6] the crown circumferential grooves include a pair provided on each side of the tire equator, The lateral grooves include a plurality of crown lateral grooves connecting the crown circumferential grooves and a plurality of middle lateral grooves connecting the crown circumferential grooves and the shoulder circumferential grooves. the hexagonal blocks include a plurality of middle blocks separated by the crown circumferential groove, the shoulder circumferential groove, and the middle lateral grooves adjacent to each other in the tire circumferential direction, The tire according to any one of disclosures 1 to 5, wherein an inner end in the tire axial direction of the widened groove portion of the middle block overlaps in the tire circumferential direction with an intersection of the crown lateral groove and the crown circumferential groove. [Disclosure 7] The tire according to Disclosure 6, wherein 80% or more of the cross-sectional area of ​​the widened groove portion of the middle block overlaps with the intersection portion of the crown lateral groove in the tire circumferential direction. [Disclosure 8] The tire according to Disclosure 6 or 7, wherein the cross-sectional area of ​​the widened groove portion of the middle block is 10% to 40% of the cross-sectional area of ​​the crown lateral groove. [Disclosure 9] the hexagonal blocks include a plurality of crown blocks separated by a pair of the crown circumferential grooves and the crown lateral grooves, The tire according to any one of disclosures 6 to 8, wherein both ends of the widened groove portions of the plurality of crown blocks in the tire axial direction overlap with the intersections of the middle lateral grooves and the crown circumferential grooves in the tire circumferential direction. [Disclosure 10] The length of the hexagonal block in the tire circumferential direction La and the axial width of the tire Wa The tire according to any one of Disclosures 1 to 9, wherein the ratio (La / Wa) is 1.2 to 1.8. [Explanation of symbols]

[0055] 1 tire 3 Circumferential groove 3A Shoulder circumferential groove 3B Crown circumferential groove 4 Yokomizo 5 Hexagonal Blocks 6 sipes 7 Widened groove W1 Groove width W2 groove width

Claims

1. A tire having a tread portion, the tread portion includes a plurality of circumferential grooves extending in a zigzag pattern in the tire circumferential direction so as to form zigzag peaks, a plurality of lateral grooves connecting the zigzag peaks of the circumferential grooves adjacent in the tire axial direction, and a plurality of hexagonal blocks formed by the circumferential grooves and the plurality of lateral grooves, the circumferential grooves include a pair of shoulder circumferential grooves arranged on tread end sides, and a pair of crown circumferential grooves arranged axially inward of the pair of shoulder circumferential grooves and on both sides of the tire equator, a groove width of the crown circumferential groove is smaller than a groove width of the pair of shoulder circumferential grooves, The hexagonal blocks are provided with sipes extending in the tire axial direction, and widened groove portions that are continuous with the sipes on the inner side in the tire radial direction and extend in the tire axial direction with a width larger than that of the sipes, the lateral grooves include a plurality of crown lateral grooves connecting the crown circumferential grooves and a plurality of middle lateral grooves connecting the crown circumferential grooves and the shoulder circumferential grooves, the hexagonal blocks include a plurality of crown blocks separated by a pair of the crown circumferential grooves and the crown lateral grooves, axially opposite ends of the widened groove portion of the crown block overlap with an intersection of the middle lateral groove and the crown circumferential groove in the tire circumferential direction, a cross-sectional area of ​​the widened groove portion of the crown block is 10% to 40% of a cross-sectional area of ​​the middle lateral groove; tire.

2. A tire having a tread portion, the tread portion includes a plurality of circumferential grooves extending in a zigzag pattern in the tire circumferential direction so as to form zigzag peaks, a plurality of lateral grooves connecting the zigzag peaks of the circumferential grooves adjacent in the tire axial direction, and a plurality of hexagonal blocks formed by the circumferential grooves and the plurality of lateral grooves, the circumferential grooves include a pair of shoulder circumferential grooves arranged on tread end sides, and a pair of crown circumferential grooves arranged axially inward of the pair of shoulder circumferential grooves and on both sides of the tire equator, a groove width of the crown circumferential groove is smaller than a groove width of the pair of shoulder circumferential grooves, The hexagonal blocks are provided with sipes extending in the tire axial direction, and widened groove portions that are continuous with the sipes on the inner side in the tire radial direction and extend in the tire axial direction with a width larger than that of the sipes, the lateral grooves include a plurality of crown lateral grooves connecting the crown circumferential grooves and a plurality of middle lateral grooves connecting the crown circumferential grooves and the shoulder circumferential grooves, the hexagonal blocks include a plurality of middle blocks separated by the crown circumferential groove, the shoulder circumferential groove, and the middle lateral grooves adjacent to each other in the tire circumferential direction, an inner end of the widened groove portion of the middle block in the tire axial direction overlaps an intersection of the crown lateral groove and the crown circumferential groove in the tire circumferential direction; a cross-sectional area of ​​the widened groove portion of the middle block is 10% to 40% of a cross-sectional area of ​​the crown lateral groove; tire.

3. A tire as described in claim 2, wherein 80% or more of the cross-sectional area of ​​the widened groove portion of the middle block overlaps with the intersection portion of the crown lateral groove in the tire circumferential direction.

4. The crown circumferential groove has a pair of groove walls extending in the longitudinal direction, 4. The tire according to claim 1, wherein at least a portion of the pair of groove walls contacts each other under normal load.

5. A tire described in any one of claims 1 to 4, wherein the groove width of the crown circumferential groove is 1% to 20% of the groove width of the shoulder circumferential groove.

6. A tire described in any one of claims 1 to 5, wherein the sipes extend in a zigzag pattern in the sipe longitudinal direction and the tire radial direction.

7. A tire described in any one of claims 1 to 6, wherein the cross-sectional shape of the widened groove portion is circular or elliptical.

8. A tire described in any one of claims 1 to 7, wherein the ratio (La / Wa) of the circumferential length La of the hexagonal block to the axial width Wa of the tire is 1.2 to 1.8.

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