JP2011051520A - Tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire capable of improving snow road performance by suppressing the fall of a land part block in a tire circumferential direction. <P>SOLUTION: The tire is provided with a main block 22 and a sub-block 82, and a sipe 100 is formed on the main block 22. The height of the sub-block 82 from the groove bottom of a circumferential groove is lower than the height from the groove bottom to the main block 22. A first lateral groove 110 is formed on a connection part between one end part of the sub-block 82 in a tire circumferential direction TC and the main block 22 continuing into the end part, and a second lateral groove 120 is formed on a connection part between the other end part of the sub-block 82 in the tire circumferential direction TC and the main block 22. One end of the first lateral groove 110 is opened to one circumferential groove side, and the other end of the first lateral groove 110 is terminated in the middle of the connection part. One end of the second lateral groove 120 is opened to the other circumferential groove side, and the other end of the second lateral groove 120 is terminated in the middle of the connection part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tire in which a sipe is formed in a land block surrounded by a circumferential groove extending in the tire circumferential direction and a lug groove intersecting the circumferential groove.

  In the snow and ice tire, a plurality of narrow grooves (hereinafter referred to as sipes) are formed in a land block surrounded by circumferential grooves extending in the tire circumferential direction. In order to improve the on-snow performance of an ice and snow tire, it is common to increase the number of sipes per land block and increase the edge length per land block. Increasing the number of sipes in one land block increases the water film removal effect and the road surface scratching effect (edge effect). On the other hand, when a large number of sipes are formed on the land block, there is a conflicting problem that the rigidity of the land block is reduced.

  Therefore, a technique has been proposed that compensates for a decrease in rigidity of the land block due to an increase in the number of sipes per one land block (see, for example, Patent Document 1). In the tire described in Patent Literature 1, a joint portion that connects the land portion blocks is disposed between the land portion blocks adjacent to each other in the tire circumferential direction.

Japanese Patent Laid-Open No. 8-67112 (page 3, FIG. 1)

  In the vehicle, when the steering wheel is turned off, the traveling direction of the vehicle and the direction of the tire are different. At this time, a lateral force is generated in the tire, and the ground contact surface of the tire is also deformed in the tread width direction. In the tire described in Patent Document 1, the joint portion and the land portion block are divided by a lateral groove (a crack groove). Therefore, for example, during non-straight running, the space between the joint and the block is easily deformed in the tread width direction.

  As described above, in the tire described in Patent Document 1, depending on the direction of the tire with respect to the traveling direction of the vehicle, the land block may easily fall down in the tire circumferential direction, and a sufficient ground contact area may not be ensured.

  Therefore, the present invention provides a tire in which a sipe is formed in a land block surrounded by a circumferential groove extending in the tire circumferential direction and a lug groove intersecting the circumferential groove. An object is to provide a tire that can prevent falling and improve performance on snow.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is that a plurality of circumferential grooves (for example, circumferential grooves 40) extending in the tire circumferential direction (tire circumferential direction TC) on the tread surface and a plurality of lugs that intersect the circumferential grooves. A tire (eg, pneumatic tire 10) in which a groove (eg, lug groove 62) is formed, and is surrounded by the pair of circumferential grooves and a plurality of lug grooves that intersect the pair of circumferential grooves. A plurality of main blocks (for example, the main block 22) and a plurality of sub blocks (for example, the sub block 82) disposed in the lug groove and adjacent to the main block. A plurality of sipes (sipe 100) are formed, and the height (height D5) of the sub block from the groove bottom portion (groove bottom portion 50) of the circumferential groove is from the groove bottom portion to the tread surface of the main block ( From height (height D2) to tread G) A first lateral groove (first lateral groove 110) is low in a connecting portion (connecting portion C1) between one end portion (end portion 92) in the tire circumferential direction of the sub block and the main block connected to the one end portion. A second lateral groove (second lateral groove) is formed in a connecting portion (connecting portion C2) between the other end portion (end portion 94) in the tire circumferential direction of the sub block and the main block connected to the other end portion. 120) is formed, one end of the first lateral groove opens to one circumferential groove side, the other end of the first lateral groove terminates in the middle of the connecting portion, and one end of the second lateral groove is The gist is that it opens to the other circumferential groove side, and the other end of the second lateral groove terminates in the middle of the connecting portion.

  According to such a tire, the sub block is adjacent to the main block. The first lateral groove is formed in a connection portion between the end portion of the sub block and the main block, and ends in the middle of the connection portion. Further, the second lateral groove is formed in a connection portion between the end portion of the sub block and the main block, and ends in the middle of the connection portion. In other words, the main block and the sub-block constituting the land block are not completely divided by the first horizontal groove and the second horizontal groove. For this reason, it can suppress that the rigidity with respect to a deformation | transformation of a tread width direction becomes low too much. In addition, the first lateral groove and the second lateral groove open to different circumferential groove sides. For this reason, it can suppress that the rigidity with respect to a deformation | transformation of a tread width direction is biased. Thereby, for example, at the time of non-straight running, the connecting portion between the sub block and the main block is not easily deformed in the tread width direction.

  Further, a plurality of sipes are formed in the main block, and a first lateral groove and a second lateral groove are formed in the connecting portion. For this reason, the edge effect by increasing the number of sipes formed in the land block and the snow column shear force acting on the snow entering the sipes increase. In addition, the first lateral groove and the second lateral groove open to different circumferential groove sides. For this reason, the snow column shearing force which acts on the snow which entered the 1st horizontal groove and the 2nd horizontal groove can be ensured uniformly in the tread width direction. Therefore, it is possible to provide a tire capable of suppressing the falling of the land block in the tire circumferential direction and improving the performance on snow.

  A second feature of the present invention relates to the first feature of the present invention, wherein the length (length W2) in the tread width direction (tread width direction TW) of the sub-block is in the tread width direction of the main block. The gist is to be shorter than the length (length W1) and fit within the width of the main block.

  A third feature of the present invention relates to the first and second features of the present invention. In the tread surface view, the sub-block is formed with a plurality of corner portions (corner portions 200 and 202). At least one of the above is an obtuse angle, and at least one of the first lateral groove and the second lateral groove is formed at the corner portion having an obtuse angle.

  A fourth feature of the present invention relates to the first to third aspects of the present invention, and is summarized in that the first lateral groove and the second lateral groove extend to a groove bottom portion (groove bottom portion 52) of the lug groove. .

  A fifth feature of the present invention relates to the first to fourth features of the present invention, wherein the length of the sub block in the tread width direction is substantially the same as the length of the main block in the tread width direction. And

  According to the features of the present invention, in a tire in which a sipe is formed in a land block surrounded by a circumferential groove extending in the tire circumferential direction and a lug groove intersecting the circumferential groove, the tire circumferential direction of the land block It is possible to provide a tire that can suppress falling into the snow and improve performance on snow.

1 is a partial development view of a tread pattern of a pneumatic tire 10 according to an embodiment of the present invention. 1 is a partial perspective view of a tread surface of a pneumatic tire 10 according to an embodiment of the present invention. It is a perspective view of subblock 82 of pneumatic tire 10 concerning an embodiment of the present invention. The shape of the cross section along the tire radial direction TD and the tread width direction TW of the 1st horizontal groove 110 of the pneumatic tire 10 which concerns on embodiment of this invention is shown. It is a partial development view of the tread pattern of the pneumatic tire 12 according to the embodiment of the present invention. It is a front view of subblock 82A concerning the embodiment of the present invention. 1 is a partial perspective view of a tread surface of a pneumatic tire 14 according to an embodiment of the present invention.

  Next, first to third embodiments of the tire according to the present invention and other embodiments will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[First Embodiment]
In the present embodiment, (1) the overall schematic configuration of the tire, (2) the detailed configuration of the main block 22, (3) the detailed configuration of the sub-block 82, (4) comparative evaluation, and (5) actions and effects. explain.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(1) Overall Schematic Configuration of Tire FIG. 1 is a partial development view of a tread pattern of a pneumatic tire 10 according to an embodiment of the present invention. Specifically, it is a partial development view of a tread pattern on the tread surface G of the pneumatic tire 10. The pneumatic tire 10 is a so-called studless tire suitable for traveling on icy and snowy roads. The pneumatic tire 10 may be filled with an inert gas such as nitrogen gas instead of air. Each part formed in the tread in the pneumatic tire 10 will be further described.

  A plurality of circumferential grooves and a plurality of lug grooves are formed on the tread surface of the pneumatic tire 10. Specifically, circumferential grooves 40, 42, 44 and 46 are formed in the pneumatic tire 10. The circumferential grooves 40, 42, 44 and 46 extend along the tire circumferential direction TC. In addition, lug grooves 60, 62, 64, 66 and 68 are formed in the pneumatic tire 10. The lug grooves 60, 62, 64, 66 and 68 intersect with the circumferential groove and are formed in a row along the tire circumferential direction TC. The lug grooves 60, 62, 64, 66 and 68 are formed along the tread width direction TW. The depth of the lug grooves 60, 62, 64, 66 and 68 in the tire radial direction TD is substantially the same as the depth of the circumferential groove and is formed constant. The pneumatic tire 10 has a plurality of land blocks. The land block is composed of a plurality of main blocks and a plurality of sub-blocks. Specifically, the pneumatic tire 10 includes main blocks 20, 22, 24, 26, and 28 and sub blocks 80, 82, 84, 86, and 88.

(2) Detailed Configuration of Main Block 22 Next, a detailed configuration of the main block 22 will be described with reference to FIGS. Since the main blocks 20, 24, 26, and 28 have the same configuration as the main block 22, detailed description thereof is omitted. FIG. 2 is a partial perspective view of the tread surface of the pneumatic tire 10 according to the embodiment of the present invention.

  The main block 22 is surrounded by a pair of circumferential grooves (a circumferential groove 40 and a circumferential groove 42) and a plurality of lug grooves 62 that intersect the circumferential groove. That is, the main block 22 is partitioned by a pair of circumferential grooves 40, circumferential grooves 42, and lug grooves 62. The main block 22 is formed in a substantially rectangular shape in the tread surface view.

  A plurality of sipes 100 are formed in the main block 22. Sub blocks 82 are adjacent to both ends of the main block 22 in the tire circumferential direction TC. Specifically, the sub block 82 is connected to both ends of the main block 22 in the tire circumferential direction TC.

  A plurality of sipes 100 are formed side by side in the tire circumferential direction TC. Specifically, the sipe 100 extends along the tread width direction TW. Both ends of the sipe 100 communicate with the circumferential groove 40 or the circumferential groove 42 located at both ends of the sipe 100 in the tread width direction TW. The depth of the sipe 100 in the tire radial direction TD is higher than the height from the groove bottom 50 of the circumferential groove 40 or the circumferential groove 42 to the tread surface G of the main block 22 (height D2 shown in FIGS. 3 and 4). shallow.

(3) Detailed Configuration of Subblock 82 Next, the detailed configuration of the subblock 82 will be described with reference to FIGS. The sub-blocks 80, 84, 86, and 88 have the same configuration as the sub-block 82, and thus detailed description thereof is omitted. FIG. 3 is a perspective view of the sub block 82 of the pneumatic tire 10 according to the embodiment of the present invention. FIG. 4 shows a cross-sectional shape along the tire radial direction TD and the tread width direction TW of the first lateral groove 110 of the pneumatic tire 10 according to the embodiment of the present invention.

  As shown in FIG. 3, the sub block 82 is disposed in the lug groove 62 and is adjacent to the main block 22. In the tread surface view, the sub block 82 is formed in a substantially rectangular shape. The height of the sub block 82 from the groove bottom 50 of the circumferential groove 42 (height D5 shown in FIGS. 3 and 4) is the height from the groove bottom 50 to the tread surface G of the main block 22 (height shown in FIG. 4). Lower than D2).

  A first lateral groove 110 is formed at one end 92 in the tire circumferential direction TC of the sub block 82, and a second lateral groove 120 is formed at the other end 94. Specifically, the first lateral groove 110 is formed in a connecting portion C1 between one end portion 92 of the sub block 82 in the tire circumferential direction TC and the main block 22 connected to the end portion 92. One end of the first lateral groove 110 in the tread width direction TW opens to the circumferential groove 40 side. Specifically, one end of the first lateral groove 110 communicates with the lug groove 62. Further, the other end of the first lateral groove 110 in the tread width direction TW terminates in the middle of the connecting portion C1.

  Further, the second lateral groove 120 is formed in a connecting portion C <b> 2 between the other end portion 94 of the sub block 82 in the tire circumferential direction TC and the main block 22 connected to the end portion 94. One end of the second lateral groove 120 in the tread width direction TW opens to the circumferential groove 42 side. Specifically, one end of the second lateral groove 120 communicates with the lug groove 62. The other end of the second lateral groove 120 in the tread width direction TW terminates in the middle of the connecting portion C2. That is, one end of the second lateral groove 120 opens to the circumferential groove 42 side that is located on the opposite side of the tread width direction TW with respect to the circumferential groove 40 side where one end of the first lateral groove 110 opens.

  The first horizontal groove 110 and the second horizontal groove 120 are formed in a substantially linear shape along the connecting portion C1 or the connecting portion C2. That is, the first horizontal groove 110 and the second horizontal groove 120 are formed in a substantially straight shape along the tread width direction TW. The first lateral grooves 110 and the second lateral grooves 120 are formed in a substantially linear shape along the tire radial direction TD. Further, the first lateral groove 110 and the second lateral groove 120 extend to the groove bottom 52 of the lug groove 62.

  As shown in FIG. 4, the length of the sub block 82 in the tread width direction TW is within the width of the main block 22. Specifically, the length W2 of the sub-block 82 in the tread width direction TW is shorter than the length W1 of the main block 22 in the tread width direction TW. Specifically, the length W2 is set to 40% or more and 80% or less with respect to the length W1. The length W3 of the first lateral groove 110 in the tread width direction TW is set to 40% or more and 80% or less with respect to the length W2. For example, the length W1 is set to 20 mm or more and 50 mm or less. The length W2 is set to 8 mm or more and 40 mm or less. The length W3 is set to 3.2 mm or more and 32 mm or less, respectively. Further, the length W4 of the second lateral groove 120 in the tread width direction TW shown in FIG. 3 is set to 40% or more and 80% or less with respect to the length W2. The total length of the length W3 and the length W4 is set to 80% or more and 160% or less with respect to the length W2.

  The groove depth along the tire radial direction TD of the lug groove 62 with respect to the tread surface G of the main block 22 is the length from the tread surface G to the groove bottom 52 of the lug groove 62. Specifically, the groove depth along the tire radial direction TD of the lug groove 62 is equal to the height from the groove bottom 50 to the tread surface G of the main block 22 and is a height D2. The height D5 in the tire radial direction TD of the sub block 82 from the groove bottom 50 of the lug groove 62 is lower than the height D2. Specifically, the height D5 is set to 30% or more and 70% or less with respect to the height D2. Since the first lateral groove 110 extends to the groove bottom 52 of the lug groove 62, the groove depth D3 of the first lateral groove 110 along the tire radial direction TD is the same length as the height D5.

  For example, the height D2 is set to 5 mm or more and 12 mm or less. The height D5 and the groove depth D3 are set to 1.5 mm or more and 8.4 mm or less.

(4) Comparative Evaluation Next, in order to further clarify the effect of the present invention, comparative evaluation performed using pneumatic tires according to the following comparative examples and examples will be described. Specifically, (4.1) Test method and (4.2) Evaluation result will be described. In addition, this invention is not limited at all by these examples.

(4.1) Test method Using each pneumatic tire, (4.1.1) Steering stability performance evaluation, (4.1.2) Acceleration performance evaluation, and (4.1.3) Braking force evaluation went. The conditions for the comparative evaluation test are as follows.

・ Tire size: 255 / 55R18
・ Rim size: Standard rim described in ETRTO ・ Test vehicle type: SUV type passenger car ・ Loading condition: Maximum load described in ETRTO (maximum load capacity)
-Set internal pressure: Standard internal pressure described in ETRTO The pneumatic tire according to Comparative Example 1 is different from the pneumatic tire according to the third embodiment in that the sipe, the first lateral groove, and the second lateral groove are not formed. The pneumatic tire according to Comparative Example 2 is the pneumatic tire according to the third embodiment in that the second lateral groove is not formed in the sub-block and only the first lateral groove that is open to the circumferential groove is formed at both ends. Different from tires. The pneumatic tire according to Comparative Example 3 is different from the pneumatic tire according to the third embodiment in that a first lateral groove and a second lateral groove whose both ends are open in the circumferential groove are formed in the sub block. The pneumatic tire according to the example is the same as the pneumatic tire according to the third embodiment.

(4.1.1) Steering stability performance evaluation Evaluation method: After each pneumatic tire is mounted on the rim and the internal pressure conditions are set, the lane change is performed on a dry road surface from a constant speed of 100 km / h to a distance of 100 m. The steering angle of the steering wheel when measured was measured. In addition, the handle snake angle of the pneumatic tire according to Comparative Example 1 is set to 100, and the measurement results of other pneumatic tires are shown as indexes. The evaluation results indicate that the larger the index value, the smaller the steering wheel horn and the better the steering stability.

(4.1.2) Evaluation of acceleration performance Evaluation method: A vehicle equipped with pneumatic tires, started on a snowy road surface at 0 km / h, and measured the time required to reach 40 km / h. In addition, the evaluation result of the comparative example 1 was set to 100, and other evaluation results were indexed and shown. An evaluation result shows that acceleration performance is so high that a numerical value is large.

(4.1.3) Evaluation of braking force Evaluation method: Time required to start at a predetermined speed and decelerate to a predetermined speed in a vehicle equipped with each pneumatic tire was measured. Specifically, on the road surface on snow, the time from starting at 30 km / h to reaching 5 km / h was measured. In addition, the evaluation result of the comparative example was set to 100, and other evaluation results were shown as an index. An evaluation result shows that braking force is excellent, so that a numerical value is large.

(4.2) Evaluation Results Table 1 shows the types of evaluated pneumatic tires and the evaluation results.

  As shown in Table 1, the pneumatic tire according to the example. Acceleration performance and braking power were improved while ensuring stable driving performance.

(5) Action / Effect As described above, according to the present embodiment, the sub block 82 is adjacent to the main block 22. The first lateral groove 110 is formed in a connection portion C1 between the end portion 92 of the sub block 82 and the main block 22, and ends in the middle of the connection portion C1. Further, the second lateral groove 120 is formed at a connection portion C2 between the end portion 94 of the sub block 82 and the main block 22, and terminates in the middle of the connection portion C2. That is, the main block 22 and the sub block 82 constituting the land block are not completely divided by the first lateral groove 110 and the second lateral groove 120. For this reason, it can suppress that the rigidity with respect to a deformation | transformation of the tread width direction TW becomes low too much. Thereby, for example, at the time of non-straight traveling, the connecting portion C1 and the connecting portion C2 between the sub block 82 and the main block 22 are not easily deformed in the tread width direction TW. Moreover, the 1st horizontal groove 110 and the 2nd horizontal groove 120 are each opened to the circumferential direction groove | channel side different. For this reason, it can suppress that the rigidity with respect to a deformation | transformation of the tread width direction TW is biased.

  The main block 22 is formed with a plurality of sipes 100, a first lateral groove 110 is formed in the connecting portion C1, and a second lateral groove 120 is formed in the connecting portion C2. For this reason, the edge effect by increasing the number of sipes formed in the land block and the snow column shearing force acting on the snow entering the sipes increase. Moreover, the 1st horizontal groove 110 and the 2nd horizontal groove 120 are each opened to the circumferential direction groove | channel side different. For this reason, the snow column shear force acting on the snow that has entered the first lateral groove 110 and the second lateral groove 120 can be ensured uniformly in the tread width direction TW. Therefore, it is possible to provide the pneumatic tire 10 capable of suppressing the falling of the land block in the tire circumferential direction and improving the performance on snow.

  In the present embodiment, the length W2 of the sub-block 82 in the tread width direction TW is shorter than the length W1 of the main block 22 in the tread width direction TW and falls within the width of the main block 22. For this reason, the drainage of the circumferential groove 40 and the circumferential groove 42 positioned at both ends of the sub-block 82 in the tread width direction TW and the drainage of the lug groove 62 can be reliably ensured. Thereby, traveling performance on an icy and snowy road can be reliably ensured.

  In the present embodiment, the first lateral groove 110 and the second lateral groove 120 extend to the groove bottom 52 of the lug groove 62. For this reason, the snow column shear force acting on the snow that has entered the first lateral groove 110 and the second lateral groove 120 can be further increased.

[Second Embodiment]
In the first embodiment described above, the sub-blocks 80, 84, 86, 88 are formed in a substantially rectangular shape in the tread surface view. On the other hand, in the second embodiment, the shape of the sub-block is different. A second embodiment will be described with reference to FIGS. FIG. 5 is a partial development view of the tread pattern of the pneumatic tire 12 according to the embodiment of the present invention. FIG. 6 is a front view of the sub-block 82A according to the embodiment of the present invention. Specifically, FIG. 6 is a tread surface view of the pneumatic tire 12.

  Note that, in the following second and third embodiments, differences from the other embodiments will be mainly described, and overlapping descriptions will be omitted. In the second embodiment, the main blocks 20A, 24A, 26A, and 28A have the same configuration as the main block 22A, and thus detailed description thereof is omitted. Similarly, the detailed description of the sub-block 82A is omitted for the sub-blocks 80A, 84A, 86A, 88A.

  As shown in FIGS. 5 and 6, in the tread surface view, the sub-block 82 </ b> A has a plurality of corners, and at least one of the corners has an obtuse angle. Specifically, as shown in FIG. 6, the corners 200 and 202 of the sub-block 82 </ b> A have an obtuse angle. That is, the sub-block 82A has an obtuse angle θ1 formed by the straight line L2 along the end in the tread width direction TW and the straight line L1 along the end in the tire circumferential direction. Further, the sub-block 82A has an obtuse angle θ2 formed by a straight line L4 along the end in the tread width direction TW and a straight line L3 along the end in the tire circumferential direction. At least one of the first lateral groove 110A and the second lateral groove 120A is formed at a corner portion that becomes an obtuse angle. Specifically, the first lateral groove 110 </ b> A is formed at a connection portion of the corner portion 200. The second lateral groove 120 </ b> A is formed at a connecting portion of the corner portion 202.

  According to the present embodiment, the corner portion 200 or the corner portion 202 has higher rigidity than the acute corner portion in the tread surface view. For this reason, even if the first transverse groove 110A or the second transverse groove 120A is formed in the corner portion 200 or the corner portion 202, it is possible to further suppress the rigidity in the tread width direction from becoming too low.

The acute corner is a corner formed by a straight line L4 (straight line L2) and a straight line L1 (straight line L3).

[Third Embodiment]
In the first embodiment described above, the sub block 82 is disposed in the lug groove 62 and is adjacent to the main block 22. The length of the sub block 82 in the tread width direction TW is within the width of the main block 22.

  On the other hand, in the third embodiment, the configuration of the sub-block 82B is different. The sub block 82B of the third embodiment will be described with reference to FIG. FIG. 7 is a partial perspective view of the tread surface of the pneumatic tire 14 according to the embodiment of the present invention.

  As shown in FIG. 7, the length of the sub block 82 </ b> B in the tread width direction TW is substantially the same as the length of the main block 22 in the tread width direction. The sub block 82B is disposed in the lug groove 62B. However, the substantial metal has a shape in which the lug groove 62B is disposed outside the sub block 82B in the tire radial direction TD.

  According to this embodiment, the drainage of the circumferential groove 40 and the circumferential groove 42 located at both ends in the tread width direction TW of the sub block 82B can be ensured. Moreover, it can further suppress that the rigidity with respect to a deformation | transformation of the tread width direction TW becomes too low.

(7) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. Should not. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, the shape of the first lateral groove 110 or the second lateral groove 120 is not necessarily limited to the above-described shape, and each vertex of the sub-block 82 in the tread surface view, that is, both ends in the tread width direction TW of the coupling portion C1 and the coupling portion C2. In addition, the first lateral groove 110 or the second lateral groove 120 may be formed. The length of the first horizontal groove 110 or the second horizontal groove 120 in the tread surface view may not be the same. Moreover, the depth of the 1st horizontal groove 110 or the 2nd horizontal groove 120 may not be the same.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

θ1, θ2: Angle, C1, C2: Connection part, G: Tread, L1, L2, L3, L4 ... Straight line, TC ... Tire circumferential direction, TD ... Tire radial direction, TW ... Tread width direction 10, 12, 14 ... Pneumatic tire, 20, 20A, 22, 22A ... Main block, 40,42 ... Circumferential groove, 50,52 ... Groove bottom, 60,62,62B ... Lug groove, 80, 80A, 82, 82A, 82B ... Sub-block, 92, 94 ... end, 100 ... sipe, 110 ... rib-like land, 110, 110A ... first transverse groove, 120, 120A ... second transverse groove, 154 ... longitudinal groove, 200, 202 ... corner

Claims (5)

A tire in which a plurality of circumferential grooves extending in the tire circumferential direction and a plurality of lug grooves intersecting the circumferential grooves are formed on a tread surface,
A plurality of main blocks surrounded by the pair of circumferential grooves and a plurality of lug grooves intersecting the pair of circumferential grooves;
A plurality of sub-blocks disposed in the lug groove and adjacent to the main block;
The main block is formed with a plurality of sipes,
The height of the sub block from the groove bottom of the circumferential groove is lower than the height from the groove bottom to the tread of the main block,
A first lateral groove is formed at a connecting portion between one end portion of the sub block in the tire circumferential direction and the main block connected to the one end portion,
A second lateral groove is formed at a connecting portion between the other end of the sub block in the tire circumferential direction and the main block connected to the other end.
One end of the first lateral groove opens to one circumferential groove side,
The other end of the first lateral groove terminates in the middle of the connecting portion,
One end of the second lateral groove opens to the other circumferential groove side,
The tire is terminated at the other end of the second lateral groove in the middle of the connecting portion.   The tire according to claim 1, wherein a length of the sub block in the tread width direction is shorter than a length of the main block in the tread width direction and fits in the width of the main block. In tread view,
The sub-block is formed with a plurality of corners,
At least one of the corners becomes an obtuse angle,
At least one of the first lateral groove and the second lateral groove is
The tire according to claim 1, wherein the tire is formed at the corner portion having an obtuse angle.   The tire according to any one of claims 1 to 3, wherein the first lateral groove and the second lateral groove extend to a groove bottom portion of the lug groove.   The tire according to any one of claims 1 to 4, wherein a length of the sub block in the tread width direction is substantially the same as a length of the main block in the tread width direction.

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