JP2011042281A - Tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire capable of suppressing the deterioration of braking performance caused by the deformation of a block-shaped land in braking, and surely exhibiting desired braking performance. <P>SOLUTION: A pneumatic tire 1 includes a block-shaped land 20 partitioned by a circumferential groove 30 extending along a tire circumferential direction TC and a lug groove 40 extending along a tread width direction TW. The ratio W/H of the length H of the block-shaped land 20 along the tire circumferential direction TC to the width W of the block-shaped land 20 along the tread width direction TW is 0.3 or smaller, a first corner 60 ground on the road surface is formed at the tread-in side of the block-shaped land 20 first, and an angle θ1 in a tread surface view of the first corner 60 is at 45° or larger and 75° or smaller. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tire including a block-shaped land portion defined by a circumferential groove extending along a tire circumferential direction and a lug groove extending along a tread width direction.

  Conventionally, various methods for the purpose of braking performance have been adopted for tires mounted on automobiles and the like. For example, a method of providing a horizontally long block in which the length in the tread width direction of a block-like land portion defined by a circumferential groove extending along the tire circumferential direction and a lug groove extending along the tread width direction is known. (See Patent Document 1). A method of forming a sipe extending in the tread width direction in such a horizontally long block is also known (see Patent Document 1).

  Such a horizontally long block increases the edge component in the tread width direction, and thus contributes to an improvement in the braking performance of the tire.

Japanese Patent No. 2879683 (page 2-3, FIG. 1)

  However, as a result of recent research, it has become clear that a tire in which a horizontally long block as described above is formed may not necessarily improve braking performance. Specifically, if the rigidity of the horizontally long block is low, it is deformed so that the stepped side end of the horizontally long block is turned during braking, and the contact area of the horizontally long block is reduced.

  For this reason, there may be a case where the expected braking performance cannot be exhibited even when the horizontally long block is employed to increase the edge component in the tread width direction.

  Accordingly, an object of the present invention is to provide a tire that can suppress a decrease in braking performance due to deformation of a block-shaped land portion during braking and can more reliably exhibit a desired braking performance.

  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 circumferential groove (circumferential groove 30) extending along the tire circumferential direction (tire circumferential direction TC) and a lug groove extending along the tread width direction (tread width direction TW). A tire (pneumatic tire 1) including a block-like land portion (for example, the block-like land portion 20) partitioned by (for example, the lug groove 40), and the block-like land portion along the tire circumferential direction. The ratio W / H between the length H and the width W of the block-shaped land portion along the tread width direction is 0.3 or less, and the stepped side of the block-shaped land portion first contacts the road surface. The first corner portion (first corner portion 60) is formed, and the angle (angle θ1) in the tread surface view of the first corner portion is 45 degrees or more and 75 degrees or less.

  According to such a feature, the ratio W / H between the length H of the block land portion along the tire circumferential direction and the width W of the block land portion along the tread width direction is 0.3 or less. For this reason, the rigidity of the block-shaped land portion can be reliably increased as compared with the rigidity of the horizontally long block whose length in the tread width direction is increased.

  Moreover, the angle in the tread surface view of the 1st corner | angular part which is the edge part by the side of depression of a block-shaped land part is 45 degree | times or more and 75 degrees or less. For this reason, it can suppress deform | transforming so that the edge part of a 1st corner | angular part may be wound in a road surface along a tire peripheral direction at the time of braking, ensuring the edge component of a tread width direction at the time of braking. That is, it can suppress that a 1st corner | angular part deform | transforms so that it may turn to the tire radial inside. Thereby, it can suppress that the ground-contact area of a block-shaped land part reduces.

  Therefore, it is possible to provide a tire that can suppress a decrease in braking performance due to deformation of the block-shaped land portion during braking and can more reliably exhibit the desired braking performance.

  According to a second aspect of the present invention, in accordance with the first aspect of the present invention, a notch (for example, a notch) is provided on at least one of the side walls (for example, the side wall 80) of the block-shaped land portion in contact with the circumferential groove. A notch 50) is formed, and the length (length H1) of the notch along the tire circumferential direction is 5 mm or more, and along the tire circumferential direction of the block-shaped land portion in contact with the circumferential groove. The width of the cutout along the tread width direction (width W1) is not less than 1/8 of the width of the block-shaped land portion. It is summarized as being less than / 2.

  A third feature of the present invention relates to the second feature of the present invention, wherein the block-shaped land portion has a second corner portion (second corner portion 70) that is convex toward the step-in side as the notch. The angle (angle θ2) in the tread surface view of the second corner portion is 45 degrees or more and 75 degrees or less.

  The fourth feature of the present invention is related to the third feature of the present invention, and is summarized in that the angle of the first corner and the angle of the second corner are substantially the same.

  A fifth feature of the present invention relates to any one of the second to fourth features of the present invention, wherein the notch has two vertices located on the side wall in the tread surface view, and more than the vertices. The internal vertex located inside the block-shaped land portion is provided, and each line connecting the vertex on the side wall and the internal vertex in a tread surface view is a straight line or a curve.

  A sixth feature of the present invention relates to any one of the second to fifth features of the present invention, wherein the notch is an approximate length of the side wall along the tire circumferential direction in the block-shaped land portion. The gist is that it is formed in a region located at ½.

  A seventh feature of the present invention relates to any one of the second to sixth features of the present invention, wherein a third corner portion (third corner) that is finally separated from the road surface is provided on the kicking side of the block-shaped land portion. The first corner portion (first corner portion 60A) is positioned on the inner side in the tread width direction with respect to the third corner portion.

  According to the characteristics of the present invention, it is possible to provide a tire that can suppress a decrease in braking performance due to deformation of a block-shaped land portion during braking and can exhibit a desired braking performance more reliably.

It is an expanded view of the tread which constitutes pneumatic tire 1 concerning the embodiment of the present invention. It is an enlarged view of the block-shaped land part 22 of the pneumatic tire 1 which concerns on embodiment of this invention. It is an enlarged view of notch 50 of pneumatic tire 1 concerning an embodiment of the present invention. It is an enlarged view of notch 50A of the pneumatic tire concerning the example 1 of change of the present invention. It is an enlarged view of the notch 50B of the pneumatic tire which concerns on the modification 2 of this invention.

  Next, an embodiment of a tire according to the present invention 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.

  About the tire which concerns on embodiment of this invention, specifically, (1) The whole structure of the pneumatic tire 1, (2) Detailed structure of the block-shaped land part 20, (3) Detailed structure of the 1st corner | angular part 60, (4) Detailed configuration of the second corner portion 70, (5) Modified example, (6) Comparative evaluation, (7) Action / effect, and (8) Other embodiments will be described.

(1) Overall Configuration of Pneumatic Tire 1 First, the configuration of the pneumatic tire 1 according to the present embodiment will be described with reference to the drawings. FIG. 1 is a development view showing a part of the tread surface 10 according to the present embodiment. The pneumatic tire 1 may be filled with an inert gas such as nitrogen gas instead of air.

  As shown in FIG. 1, the pneumatic tire 1 includes a block-shaped land portion 20 defined by a circumferential groove 30 extending along the tire circumferential direction TC and a lug groove 40 extending along the tread width direction TW. .

  The block-shaped land portion 20 includes a block-shaped land portion 22 and a block-shaped land portion 24 that are located on both sides of the tread width direction TW through the tire equator line CL. The block land portions 20 are provided at a predetermined cycle along the tire circumferential direction TC. The block land portion 22 and the block land portion 24 are not aligned in the tread width direction TW, and are provided at different positions.

  The circumferential groove 30 includes a circumferential groove 34 passing on the tire equator line CL, a circumferential groove 32 positioned on both sides of the circumferential groove 34 in the tread width direction TW, and a circumferential groove 36.

  A plurality of lug grooves 40 are formed at predetermined intervals in the tire circumferential direction TC. The lug groove 40 extends obliquely with respect to the tread width direction TW when viewed from the tread surface, and opens into at least one of the circumferential groove 32 and the circumferential groove 36 and the circumferential groove 34. The lug groove 40 has a width narrower than each width along the tread width direction TW of at least one of the circumferential groove 32, the circumferential groove 34, and the circumferential groove 36.

(2) Detailed configuration of the block land portion 20 Next, the configuration of the block land portion 20 described above will be described with reference to the drawings. FIG. 2 is a front view showing the block-shaped land portion 22 of the pneumatic tire 1 according to the present embodiment. In the following description, the block land portion 22 will be described as a detailed configuration of the block land portion 20. Since the block-like land portion 24 has the same configuration as that of the block-like land portion 22, the description thereof is omitted.

  As shown in FIG. 2, the block land portion 22 is formed long along the tire circumferential direction TC. Specifically, the shape of the block land portion 22 is formed in a substantially parallelogram in the tread surface view. Specifically, in the block-shaped land portion 22, the ratio W / the length H of the block-shaped land portion 22 along the tire circumferential direction TC and the width W of the block-shaped land portion 22 along the tread width direction TW. H is 0.3 or less.

  The length H of the block land portion 22 indicates the length in the tire circumferential direction TC from the end to the end of the block land portion 22 along the tire circumferential direction TC. That is, in the present embodiment, the length H indicates the length in the tire circumferential direction TC from the end portion 26a to the end portion 26b. Similarly, the width W of the block land portion 22 indicates the length in the tread width direction TW from the end portion to the end portion of the block land portion 22 along the tread width direction TW. That is, in the present embodiment, the width W indicates the length in the tread width direction TW from the end portion 26a to the end portion 26b.

  A notch 50 is formed in the block land portion 22. Specifically, the notch 50 is formed in at least one of the side walls of the block land portion 22 that contacts the circumferential groove 32. For example, the notch 50 is formed in the side wall 80 of the block land portion 22. The notch 50 is formed in the block-shaped land portion 22 in a region located approximately half of the length H2 of the side wall 80 along the tire circumferential direction TC. Specifically, the notch 50 is formed along the center line CL1 in the tire circumferential direction TC of the block-shaped land portion 22 from a region located approximately half of the length H2 of the side wall 80.

  The notch 50 has a shape connecting three vertices in the tread surface view. Specifically, the notch 50 includes vertices 52a and 52b located on the side wall 80, and an inner vertex 52c located on the inner side of the block land portion 22 than the vertices 52a and 52b. The lines L1 and L2 connecting the vertices 52a and 52b on the side wall 80 in the tread surface view and the internal vertices 52c are straight lines or curves. Specifically, the line L1 is a line connecting the vertex 52a and the internal vertex 52c, and the shape of the line L1 in the tread surface view is a curved shape that is recessed toward the center of the notch 50. For example, the shape of the line L1 in the tread surface view is set to a curve of R5 or more. The line L2 is a line connecting the vertex 52b and the internal vertex 52c, and the shape of the line L2 in the tread surface view is substantially linear.

  The length H1 of the notch 50 along the tire circumferential direction TC is 5 mm or more. The length H1 of the notch 50 is not more than 0.3 times the length H2 of the side wall 80 along the tire circumferential direction TC of the block land portion 22 in contact with the circumferential groove 32. The length H1 is more preferably 7 mm or more and 0.2 times or less of the length H2.

  The width W1 of the notch 50 along the tread width direction TW is 1/8 or more and less than 1/2 of the width W of the block-shaped land portion 22. The width W1 is more preferably 1/5 or more and less than 1/3 of the width W.

(3) Detailed Configuration of First Corner 60 As shown in FIG. 2, the first corner 60 is formed in the block-shaped land portion 22. Specifically, the first corner portion 60 is formed on the stepping side of the block land portion 22. The first corner 60 first contacts the road surface in the block land portion 22. The first corner portion 60 includes ends of the block-shaped land portion 22 in the tire circumferential direction TC and the tread width direction TW. That is, the 1st corner | angular part 60 is an area | region including the edge part 26a formed in the stepping side among the edge part 26a or the edge part 26b. The angle θ1 in the tread surface view of the first corner portion 60 is not less than 45 degrees and not more than 75 degrees. Specifically, the angle θ1 is an angle formed by the side wall 82 and the side wall 80 of the block-shaped land portion 22 that is in contact with the lug groove 40 in the tread surface view. When the side wall 80 and the side wall 82 are curved in the tread surface view, the side wall 80 and the side wall 82 are formed by a tangent line near the end portion 26a of the side wall 80 forming the first corner 60 and a tangent line near the end portion 26a of the side wall 82. This angle is defined as angle θ1.

  Further, a third corner portion 72 that is finally separated from the road surface is formed on the kicking side of the block-shaped land portion 22. The first corner portion 60 is located on the inner side in the tread width direction with respect to the third corner portion 72.

(4) Detailed Configuration of Second Corner 70 Next, the shape of the second corner 70 will be further described with reference to the drawings. FIG. 3 is a front view showing an enlarged view of the second corner portion 70 of the pneumatic tire 1 according to the present embodiment.

  As shown in FIG. 3, a second corner 70 is formed in the block land portion 22. Specifically, the second corner portion 70 is formed by the notch 50 and is convex toward the stepping side in the tread surface view. Specifically, the second corner portion 70 is a region formed on the kicking side of the notch 50. The angle θ2 in the tread surface view of the second corner portion 70 is not less than 45 degrees and not more than 75 degrees. Specifically, the angle θ <b> 2 is an angle formed by the side wall 54 that forms the side wall on the kick-out side of the notch 50 and the side wall 80 in the tread surface view. When the side wall 54 and the side wall 80 are curved in the tread surface view, the side wall 54 and the side wall 80 are formed by a tangent line near the apex 52b of the side wall 54 forming the second corner 70 and a tangent line near the apex 52b of the side wall 80. The angle is defined as an angle θ2. The angle θ1 of the first corner portion 60 and the angle θ2 of the second corner portion 70 are substantially the same. The “substantially the same” means that the angle of the other is set within a range of ± 5 degrees when either one is used as a reference.

(5) Modification Example Next, a modification example of the notch 50 of the pneumatic tire 1 according to the above-described embodiment will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same part as the notch 50 of the pneumatic tire 1 which concerns on embodiment mentioned above, and a different part is mainly demonstrated.

(5.1) Modification 1
The configuration of the pneumatic tire notch 50A according to the first modification will be described with reference to the drawings. FIG. 4 is an enlarged view of the notch 50A of the pneumatic tire according to the first modification.

  In the embodiment described above, the notch 50 is formed by the line L1 that is a curve of R5 or more and the substantially straight line L2 in the tread surface view. On the other hand, in the first modification, as shown in FIG. 4, the line connecting the vertex 52a and the internal vertex 52c is formed in a curved shape that is further curved than the line L1, and the vertex 52b, A line connecting the vertex 52c is formed in a curved shape.

(5.2) Modification 2
First, the structure of the notch 50B of the pneumatic tire according to Modification 2 will be described with reference to the drawings. FIG. 5 is an enlarged view of the notch 50B of the pneumatic tire according to the second modification.

  In the embodiment described above, the notch 50 is formed by the line L1 that is a curve of R5 or more and the substantially straight line L2 in the tread surface view. On the other hand, in the modified example 2, as shown in FIG. 5, the line connecting the vertex 52a and the internal vertex 52c and the line connecting the vertex 52b and the internal vertex 52c are each formed in a straight line. The

(6) 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, (6.1) Evaluation method and (6.2) Evaluation result will be described. In addition, this invention is not limited at all by these examples.

(6.1) Evaluation method Using two types of tires, the braking performance and uneven wear were evaluated. Data on pneumatic tires were measured under the following conditions.
・ Tire size: 195 / 65R15
・ Rim wheel size: Standard rim described in ETRTO ・ Tire type: Normal tire (tires other than studless tires)
-Vehicle type: Domestic car sedan-Internal pressure: Standard specified internal pressure-Load conditions: Vehicle load + 2 passengers

  As shown in Table 1, the pneumatic tire according to the comparative example and the pneumatic tire according to the example have a ratio W / H, the presence / absence of a notch, and the ratio of the notch width W1 to the width W of the block land portion. The difference between (W / W1), angle θ1, and angle θ2 is the same.

  Specifically, the pneumatic tires according to Examples 1 to 4 are substantially the same as the pneumatic tire 1 according to the present embodiment, and the presence or absence of notches, the ratio W / H, the angle θ1, and the angle θ2 are different. ing. Comparative Example 1 and Comparative Examples 3 to 9 are different from the pneumatic tire 1 in that the angle θ1 is smaller than 45 degrees or larger than 75 degrees.

Comparative Examples 2, 6, and 7 differ from the pneumatic tire 1 in that the ratio W / H is set to be larger than 0.3.

(6.1.1) Evaluation of braking performance Evaluation method: On a test course, the distance from a vehicle equipped with each pneumatic tire to a stop of full braking from 80 km / h was measured. In addition, the evaluation result of the pneumatic tire which concerns on a comparative example was set to 100, and the evaluation result of each pneumatic tire was shown by the contrast index. The larger the numerical value of the evaluation result, the higher the braking performance is obtained.

(6.1.2) Uneven wear evaluation test Evaluation method: The depth from the block land to the bottom of the notch was measured. Specifically, in the tread surface view, the depth of the bottom of the notch was continuously measured so as to pass through the center of the notch along the tire circumferential direction, and the average value from the block land portion was calculated.

  After traveling 5,000 km, the depth of the bottom of the notch was measured in the same manner as before traveling, and the amount of uneven wear was calculated by comparing the depth before and after traveling.

(6.2) Evaluation Results The evaluation results of each pneumatic tire will be described with reference to Table 1. As shown in Table 1, it was shown that the tire according to the example obtained higher braking performance than the tire according to the comparative example. Furthermore, in Examples 3 to 6, it was possible to suppress uneven wear while ensuring high braking performance.

(7) Action / Effect According to the pneumatic tire 1, the ratio between the length H of the block-shaped land portion 20 along the tire circumferential direction TC and the width W of the block-shaped land portion 20 along the tread width direction TW. W / H is 0.3 or less. For this reason, the rigidity of the block-shaped land portion 20 can be reliably increased as compared with the rigidity of the horizontally long block in which the length in the tread width direction TW is increased.

  In addition, the angle θ1 in the tread surface view of the first corner portion 60 that is the end portion on the step-down side of the block land portion 20 is not less than 45 degrees and not more than 75 degrees. For this reason, it can suppress that the edge part of the 1st corner | angular part 60 deform | transforms into the road surface in the tire circumferential direction TC at the time of braking, ensuring the edge component of the tread width direction TW at the time of braking. That is, it can suppress that the 1st corner | angular part 60 deform | transforms so that it may turn to the tire radial inside. Thereby, it can suppress that the ground-contact area of the block-shaped land part 20 reduces.

  Accordingly, it is possible to provide the pneumatic tire 1 that can suppress a decrease in the braking performance due to the deformation of the block-shaped land portion 20 during braking and can exhibit the desired braking performance more reliably.

  If the ratio W / H is larger than 0.3, the rigidity of the block-shaped land portion 20 is reduced, and there is a possibility that the step-side end of the block-shaped land portion 20 is turned during braking. is there. When the angle θ1 is smaller than 45 degrees, the block-shaped land portion 20 cannot sufficiently secure an edge component in the tread width direction TW during braking, and cannot exhibit the expected braking performance. Further, when the angle θ1 is larger than 75 degrees, there is a possibility that the first corner portion 60 is deformed so as to be turned during braking.

  In the present embodiment, the notch 50 is formed in the side wall 80 of the block-shaped land portion 22 that contacts the circumferential groove 32. For this reason, the side wall 54 on the kick-out side of the notch 50 functions as an edge component in the tread width direction TW during braking. That is, the block land portion 22 can increase the edge component in the tread width direction TW.

  Furthermore, the length H1 of the notch 50 is 5 mm or more and 0.3 times or less of the length H2 of the side wall 80 along the tire circumferential direction TC of the block-shaped land portion 22. Further, the width W1 of the notch 50 is 1/8 or more and less than 1/2 of the width W of the block-shaped land portion 22. For this reason, the rigidity of the block-shaped land part 22 falls and the edge component of the tread width direction TW can be increased while suppressing the occurrence of uneven wear. Accordingly, the braking performance of the pneumatic tire 1 can be further improved while suppressing the occurrence of uneven wear.

  In the present embodiment, the block-shaped land portion 22 is formed with a second corner portion 70 that is convex toward the stepping side by the notch 50. For this reason, the second corner portion 70 functions as an edge component during braking. Specifically, the angle θ2 of the second corner portion 70 in the tread surface view is not less than 45 degrees and not more than 75 degrees. For this reason, it can suppress that the 2nd corner | angular part 70 is deform | transformed so that it may be turned at the time of braking, increasing the edge component of the tread width direction TW at the time of braking. Accordingly, the braking performance of the pneumatic tire 1 can be further improved while suppressing the occurrence of uneven wear.

  In the present embodiment, the angle θ 1 is formed by the side wall 80 and the side wall 82, and the angle θ 2 is formed by the side wall 80 and the side wall 54. The angle θ1 of the first corner portion 60 and the angle θ2 of the second corner portion 70 are substantially the same. For this reason, in the block-shaped land part 22, the distance from the side wall 82 to the side wall 54 along the tire circumferential direction TC is kept constant. Thereby, the rigidity of the block-shaped land part 22 falls by the notch 50, and it can further suppress that a partial wear generate | occur | produces.

  In the present embodiment, the lines L1 and L2 that connect the vertex 52a and vertex 52b and the internal vertex 52c in the tread surface view are straight lines or curves. For this reason, it is possible to increase the edge component in the tread width direction TW while suppressing a decrease in the rigidity of the block-shaped land portion 22.

  Furthermore, the shape of the line L <b> 1 in the tread surface view is a curved shape that is recessed toward the center of the notch 50. For this reason, it can further suppress that the rigidity of block-like land part 22 falls.

  In the present embodiment, the notch 50 is formed in a region located approximately half of the length H <b> 2 of the side wall 80. For this reason, the notch 50 can suppress a reduction in the rigidity of a part of the block-shaped land portion 22.

(8) 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 embodiment of the present invention can be modified as follows. In the present embodiment, in the block-like land portion 22 and the block-like land portion 24, the first corner portion 60 is located in the same direction of the tire circumferential direction TC and the tread width direction TW. The present invention is not limited to this. For example, the first corner portion 60 may be located on the inner side in the tread width direction with respect to the third corner portion 72. Generally, in the tread, the contact pressure of the shoulder portion located outside the tread width direction TW is higher than the contact pressure of the central portion from the tire equator line CL than the shoulder portion. For this reason, the 1st corner | angular part 60 provided in the tread width direction inner side rather than the 3rd corner | angular part 72 is provided in the area | region where a contact pressure is lower than a shoulder part. Therefore, it is possible to further suppress the first corner portion 60 from being deformed so as to be turned up.

  In the present embodiment, the block-shaped land portion 20 is provided at a predetermined cycle along the tire circumferential direction TC. However, the present invention is not limited thereto, and for example, the block-shaped land portion 20 may not have periodicity, and the tire The sizes of the blocks along the circumferential direction TC may be different.

  In the present embodiment, the pneumatic tire 1 is filled with gas such as air inside, but is not limited thereto, and may be a solid tire that is not filled with gas.

  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.

  CL: tire equator line, L1, L2 ... line, TC ... tire circumferential direction, TW ... tread width direction, W ... width, W / H ... ratio, W1: width, 1 ... pneumatic tire, 10 ... tread tread, 20 , 22, 24 ... block-shaped land portion, 26a, 26b ... end, 30, 32, 34, 36 ... circumferential groove, 40 ... lug groove, 50, 50A, 50B ... notch, 52a, 52b ... vertex, 52c ... inner vertex, 54 ... side wall, 60, 60A ... first corner, 70 ... second corner, 72, 72A ... third corner, 80, 82 ... side wall

Claims (7)

A tire including a block-shaped land portion defined by a circumferential groove extending along a tire circumferential direction and a lug groove extending along a tread width direction,
The ratio W / H between the length H of the block-shaped land portion along the tire circumferential direction and the width W of the block-shaped land portion along the tread width direction is 0.3 or less,
On the stepping side of the block-shaped land portion, a first corner portion that first contacts the road surface is formed,
A tire having an angle of 45 degrees or more and 75 degrees or less in the tread surface view of the first corner portion. A notch is formed in at least one of the side walls of the block-shaped land portion in contact with the circumferential groove,
The length of the notch along the tire circumferential direction is not less than 5 mm and not more than 0.3 times the length of the side wall along the tire circumferential direction of the block-shaped land portion in contact with the circumferential groove. Yes,
The tire according to claim 1, wherein a width of the notch along the tread width direction is 1/8 or more and less than 1/2 of the width of the block-shaped land portion. In the block-shaped land portion, a second corner portion that is convex toward the stepping side is formed by the notch,
The tire according to claim 2, wherein an angle of the second corner portion in a tread surface view is 45 degrees or more and 75 degrees or less.   The tire according to claim 3, wherein the angle of the first corner and the angle of the second corner are substantially the same. The notch is in the tread surface view,
Two vertices located on the side wall, and an internal vertex located inside the block-shaped land portion from the vertex,
The tire according to any one of claims 2 to 4, wherein each line connecting the vertex on the side wall in the tread surface view and the internal vertex is a straight line or a curve. The notch is
The tire according to any one of claims 2 to 5, wherein the block-shaped land portion is formed in a region located approximately half the length of the side wall along the tire circumferential direction. On the kick-out side of the block-shaped land portion, a third corner portion that finally leaves the road surface is formed,
The tire according to any one of claims 3 to 6, wherein the first corner portion is located on the inner side in the tread width direction with respect to the third corner portion.

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