JP2019026204A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire capable of securing wet performance and reducing noise.SOLUTION: A pneumatic tire comprises on a tread face 3: plural circumferential main grooves 20; plural lug grooves 40; and plural land parts 10. At least one land part 10 out of the plural land parts 10 has; plural center lug grooves 41 being lug grooves 40 whose one end is opened to the circumferential main groove 20 and other end terminates in the land part 10; and notches 90 positioned on an extension line of an end part on a side terminated in the land part 10 on the center lug groove 41, and opened to the circumferential main groove 20. The center lug grooves 41 and the notches 90 are alternately arranged on the tire circumferential direction; and therefore the center lug grooves 41 and the notches 90 are arranged in a zigzag state.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire.

  In pneumatic tires, a plurality of grooves are formed on the tread surface for the purpose of draining water between the tread surface and the road surface when traveling on wet road surfaces. It can also be a cause. For this reason, some conventional pneumatic tires attempt to reduce uneven wear by devising the shape and arrangement of the grooves.

  For example, in the pneumatic tire described in Patent Document 1, a plurality of ribs are formed by three main grooves extending in the tire circumferential direction, and a lateral groove extending in the tire width direction is formed in each rib. The width of the lateral groove communicating with the lateral groove is different from the width of the lateral groove communicating with the outer main grooves. As a result, the difference between the effective grounding length of the rib facing the central main groove and the effective grounding length of the rib facing the outer main grooves can be reduced, and the grounding pressure applied to both ends of the rib can be made uniform. Therefore, it is possible to improve center wear in which the inner ends of both ribs facing the central main groove are worn at an early stage.

Japanese Patent No. 3471518

  Here, in recent years, there is a demand for reduction of passing sound emitted from the ground contact area of the pneumatic tire when the vehicle is traveling. Passing sound tends to increase when the tapping surface hits the ground in the tire width direction through the lug groove extending in the tire width direction, and the groove width and depth of the lug groove are limited. By reducing the volume of the lug groove, it can be suppressed to some extent. However, since the lug groove contributes to drainage, reducing the volume of the lug groove leads to a decrease in drainage and a decrease in wet performance, which is traveling performance such as traction performance on a wet road surface. For this reason, it has been very difficult to reduce noise while suppressing a decrease in wet performance.

  This invention is made | formed in view of the above, Comprising: It aims at providing the pneumatic tire which can aim at noise reduction, ensuring wet performance.

  In order to solve the above-described problems and achieve the object, a pneumatic tire according to the present invention is formed on a tread surface, and is formed on the tread surface with a plurality of circumferential main grooves extending in the tire circumferential direction. A plurality of lug grooves extending in the width direction, and a plurality of land portions defined by at least one end in the tire width direction by the circumferential main grooves, and at least one of the land portions among the plurality of land portions The one side opening lug groove which is the lug groove whose one end opens in the circumferential main groove and the other end terminates in the land portion, and the end on the side terminating in the land portion in the one side opening lug groove A plurality of notches that are located on the extension line of the portion and open to the circumferential main groove, and the one-sided opening lug groove and the notch are arranged in the tire circumferential direction. The notches are arranged alternately. By Rukoto, characterized by being disposed in a staggered pattern arrangement.

  In the pneumatic tire, the one-side opening lug groove has a length L1 in the tire width direction of the one-side opening lug groove with respect to a width W1 in the tire width direction of the land portion where the one-side opening lug groove is disposed. Is preferably in the range of 0.3 ≦ (L1 / W1) ≦ 0.6.

  In the pneumatic tire, the notch has a length L2 in the tire width direction of the notch of 0.05 ≦≦ the width W1 in the tire width direction of the land portion where the notch is disposed. It is preferable to be within the range of (L2 / W1) ≦ 0.20.

  In the pneumatic tire, the width of the notch increases in the tire circumferential direction as it approaches the circumferential main groove from a position away from the circumferential main groove where the notch is opened in the tire width direction. The relationship between the minimum width W2 and the maximum width W3 in the tire circumferential direction is preferably in the range of 0.4 ≦ (W2 / W3) ≦ 0.6.

  In the pneumatic tire, the one-side opening lug groove includes a constant width portion formed with a constant groove width and a widening portion where the groove width changes, and the widening portion opens into the circumferential main groove. The constant width portion extends from the side opposite to the side opening in the circumferential main groove in the widened portion to the end portion on the side terminating in the land portion in the one side opening lug groove, The widened portion has a groove width that increases from the constant width portion side toward the side that opens in the circumferential main groove, and at the position where the widened portion opens in the circumferential main groove. The relationship between the groove width W5 and the groove width W4 of the constant width portion is preferably in the range of 0.4 ≦ (W4 / W5) ≦ 0.6.

  In the pneumatic tire, the one side opening lug groove has a length L3 of the constant width portion in the tire width direction of 0.6 ≦ (L3) with respect to a length L1 of the one side opening lug groove in the tire width direction. / L1) is preferably within the range of 0.8.

  In the pneumatic tire, a groove depth of the widened portion is deeper than a groove depth of the constant width portion, and a minimum groove depth D1 of the constant width portion is a maximum groove depth D2 of the widened portion. On the other hand, it is preferable that it is in the range of 0.2 ≦ (D1 / D2) ≦ 0.5.

  In the pneumatic tire, the maximum groove depth D2 of the widened portion is 0.8 ≦ (D2 / DC) ≦ 1.0 with respect to the groove depth DC of the circumferential main groove where the widened portion opens. It is preferable to be within the range.

  In the pneumatic tire, LC is defined as a distance in the tire circumferential direction between the one side opening lug grooves that are opened in the same circumferential main groove and are adjacent in the tire circumferential direction, and a width in the tire circumferential direction of the constant width portion is defined as W6. In this case, the relationship between the distance LC and the width W6 is preferably in the range of 0.05 ≦ (W6 / LC) ≦ 0.15.

  In the pneumatic tire, the land portion where the one-side opening lug groove and the notch are disposed is not formed with grooves and sipes whose both ends open to the circumferential main groove, and both ends It is preferable that a closed sipe that terminates in the land portion is provided.

  In the pneumatic tire, the closed sipe has a shallow bottom portion that is shallower than depths at both ends of the closed sipe, and a minimum depth D3 at the shallow bottom portion, and the closed sipe The relationship with the maximum sipe depth D4 is preferably in the range of 0.4 ≦ (D3 / D4) ≦ 0.6.

  In the pneumatic tire, at least three of the circumferential main grooves are provided side by side in the tire width direction, and the land portion in which the one side open lug grooves and the notches are disposed includes at least two rows. Two rows of the land portions that are arranged adjacent to each other in the tire width direction through the circumferential main groove, the one side opening lug groove and the notch are arranged and are adjacent to each other through the circumferential main groove Among these, the distance in the tire circumferential direction between the one-side opening lug groove adjacent to the tire circumferential direction arranged in one of the land portions and the notch is L4, and is disposed in the other land portion. The one side opening lug groove defining the distance L4 and the notch are opened in the same circumferential main groove as the notch, and the position in the tire circumferential direction defines the distance L4 between the one side opening lug groove and the notch Located on the one side opening lug groove or front Of the distances in the tire circumferential direction between the notch and the one side opening lug groove defining the distance L4 and the notch, when the shorter distance is L5, the relationship between the distance L4 and the distance L5 is 0.4 ≦ (L5 / L4) ≦ 0.5 is preferable.

  In the pneumatic tire, three circumferential main grooves are provided side by side in the tire width direction, and the land portion is provided by four rows in the tire width direction. The notch is a shoulder land which is the land portion located on the outer side in the tire width direction of the shoulder circumferential main groove which is the circumferential main groove located on the outermost side in the tire width direction among the three circumferential main grooves. A plurality of shoulder lug grooves that are the lug grooves that are opened from the outer side in the tire width direction with respect to the shoulder circumferential main grooves are formed in the land portions other than the portions in a staggered arrangement. And a distance in the tire circumferential direction between the one-side open lug groove adjacent to the shoulder circumferential direction and the notch through the shoulder circumferential main groove in the tire circumferential direction is L4. When The shoulder lug groove that is located between the one-side opening lug groove whose position in the tire circumferential direction defines the distance L4 and the notch among the plurality of the shoulder lug grooves, and the one-side opening lug that defines the distance L4 Of the distances between the grooves and the notches in the tire circumferential direction, when the shorter distance is L6, the relationship between the distance L4 and the distance L6 is 0.4 ≦ (L6 / L4) ≦ 0. It is preferable to be within the range of 5.

  The pneumatic tire according to the present invention has an effect that noise reduction can be achieved while ensuring wet performance.

FIG. 1 is a meridional cross-sectional view showing a main part of a pneumatic tire 1 according to an embodiment. FIG. 2 is an AA arrow view of FIG. FIG. 3 is a detailed view of part B of FIG. FIG. 4 is a detailed view of part C in FIG. 5 is a cross-sectional view taken along line EE in FIG. 6 is a cross-sectional view taken along line FF in FIG. FIG. 7 is a detailed view of a portion G in FIG. FIG. 8 is a detailed view of a portion H in FIG. FIG. 9 is a detailed view of a portion J in FIG. FIG. 10 is an explanatory diagram of outer regions of the first shoulder lug groove and the second shoulder lug groove. FIG. 11 is an explanatory diagram illustrating a relationship between a distance between adjacent first center lug grooves and a constant width portion. FIG. 12 is an explanatory diagram illustrating a relationship between a distance between adjacent second center lug grooves and a constant width portion. FIG. 13 is an explanatory diagram of the relative positional relationship between the center lug groove and the notch provided in the land portion adjacent to each other via the circumferential main groove. FIG. 14 is an explanatory diagram of a relative positional relationship among a center lug groove, a notch, and a shoulder lug groove that are provided in adjacent land portions via a shoulder circumferential main groove. FIG. 15 is an explanatory view of a modified example of the pneumatic tire according to the embodiment, in which a sipe is formed on the tread surface. FIG. 16 is a detailed view of the bending sipe shown in FIG. 17 is a cross-sectional view taken along the line KK of FIG. 18 is a detailed view of the lug sipe shown in FIG. 19 is a cross-sectional view taken along line MM in FIG. FIG. 20A is a chart showing the results of a performance test of a pneumatic tire. FIG. 20B is a chart showing the results of a performance test of a pneumatic tire. FIG. 20C is a chart showing the results of the performance test of the pneumatic tire. FIG. 20D is a chart showing the results of a performance test of a pneumatic tire. FIG. 20E is a chart showing the results of the performance test of the pneumatic tire.

  Hereinafter, an embodiment of a pneumatic tire according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be replaced by those skilled in the art and can be easily conceived, or those that are substantially the same.

  In the following description, the tire width direction refers to a direction parallel to the rotational axis of the pneumatic tire, the inner side in the tire width direction refers to the direction toward the tire equator in the tire width direction, and the outer side in the tire width direction refers to the tire width. The direction opposite to the direction toward the tire equatorial plane. Further, the tire radial direction means a direction orthogonal to the tire rotation axis, the tire radial direction inner side means the direction toward the tire rotation axis in the tire radial direction, and the tire radial direction outer side means from the tire rotation axis in the tire radial direction. The direction to leave. Further, the tire circumferential direction refers to a direction rotating around the tire rotation axis.

Embodiment
FIG. 1 is a meridional cross-sectional view showing a main part of a pneumatic tire 1 according to an embodiment. The pneumatic tire 1 shown in FIG. 1 is provided with a tread portion 2 at the outermost portion in the tire radial direction when viewed in a meridional section that is a section passing through the tire rotation axis in a direction parallel to the tire rotation axis. The surface of the tread portion 2, that is, the portion that comes into contact with the road surface when the vehicle (not shown) on which the pneumatic tire 1 is mounted is formed as a tread surface 3. A plurality of circumferential main grooves 20 extending in the tire circumferential direction and lug grooves 40 (see FIG. 2) extending in the tire width direction are formed on the tread surface 3. On the tread surface 3, a plurality of land portions 10 are defined by the plurality of circumferential main grooves 20 and lug grooves 40, and the plurality of land portions 10 have at least one end in the tire width direction. It is demarcated by the circumferential main groove 20.

  Both ends of the tread portion 2 in the tire width direction are formed as shoulder portions 4, and sidewall portions 5 are disposed from the shoulder portion 4 to a predetermined position inside the tire radial direction. That is, the sidewall portions 5 are disposed at two places on both sides of the pneumatic tire 1 in the tire width direction.

  Further, bead portions 30 are located on the inner side in the tire radial direction of the respective sidewall portions 5, and the bead portions 30 are disposed at two locations on both sides of the tire equatorial plane CL, similarly to the sidewall portions 5. ing. That is, a pair of bead portions 30 are disposed on both sides of the tire equatorial plane CL in the tire width direction. Each of the pair of bead portions 30 is provided with a bead core 31, and a bead filler 35 is disposed on the outer side of each bead core 31 in the tire radial direction. The bead core 31 is formed by winding a bead wire, which is a steel wire, in a ring shape. The bead filler 35 is a rubber material disposed in a space formed by folding an end portion in the tire width direction of the carcass 6 to be described later outward in the tire width direction at the position of the bead core 31.

  A belt layer 7 is provided on the inner side in the tire radial direction of the tread portion 2. The belt layer 7 has, for example, a multilayer structure in which a pair of cross belts 7a and 7b and a belt cover 7c are laminated, and a plurality of belt cords made of steel or organic fiber materials such as polyester, rayon, and nylon are covered with a coat rubber. And is formed by rolling. Among these, at least a pair of cross belts 7a and 7b have different belt angles defined as inclination angles in the tire width direction of the belt cords with respect to the tire circumferential direction, and are laminated by crossing the inclination directions of the belt cords. It is comprised as what is called a cross-ply structure.

  A carcass 6 including a radial ply cord is continuously provided on the inner side in the tire radial direction of the belt layer 7 and on the tire equatorial plane CL side of the sidewall portion 5. The carcass 6 has a single-layer structure composed of one carcass ply or a multilayer structure formed by laminating a plurality of carcass plies, and is bridged in a toroidal manner between bead cores 31 disposed on both sides in the tire width direction. It constitutes the tire skeleton. Specifically, the carcass 6 is disposed from one bead portion 30 to the other bead portion 30 of the pair of bead portions 30 located on both sides in the tire width direction so as to wrap the bead core 31 and the bead filler 35. The bead portion 30 is wound back along the bead core 31 from the inner side to the outer side in the tire width direction. The carcass ply of the carcass 6 arranged in this way is a steel cord, which is a carcass cord made of a steel material, and is formed by rolling a plurality of steel cords with a coat rubber. That is, the carcass 6 is configured using a steel carcass material.

  An inner liner 8 is formed along the carcass 6 on the inner side of the carcass 6 or on the inner side of the carcass 6 in the pneumatic tire 1.

  FIG. 2 is an AA arrow view of FIG. Three circumferential main grooves 20 are provided side by side in the tire width direction, and four rows of land portions 10 defined by the circumferential main grooves 20 are provided side by side in the tire width direction. Of the three circumferential main grooves 20, the circumferential main groove 20 located at the center in the tire width direction is provided as a center circumferential main groove 21, and the two circumferential main grooves 20 located on the outermost side in the tire width direction. The groove 20 is provided as a shoulder circumferential main groove 22. That is, the two shoulder circumferential main grooves 22 are disposed on both sides of the tire equatorial plane CL in the tire width direction, and the center circumferential main grooves 21 are two shoulder circumferential main grooves in the tire width direction. 22 and is disposed on the tire equatorial plane CL. These circumferential main grooves 20 are all formed to extend linearly in the tire circumferential direction.

  The circumferential main grooves 20 are all formed to extend linearly in the tire circumferential direction, and have a groove width in the range of 4 mm to 8 mm and a groove depth in the range of 10 mm to 20 mm. The circumferential main groove 20 may be formed in a shape other than a linear shape, for example, may be formed in a wavy shape or a zigzag shape that repeatedly extends in the tire width direction while extending in the tire circumferential direction. Good.

  As the lug groove 40, the center lug groove 41 disposed between the adjacent center circumferential main groove 21 and the shoulder circumferential main groove 22 and the outer side of the shoulder circumferential main groove 22 in the tire width direction are disposed. Shoulder lug grooves 42 are provided. Among these, the center lug groove 41 has one end in the tire width direction opening into the center circumferential main groove 21 or the shoulder circumferential main groove 22, and the other end of the center lug groove 41 and the shoulder circumferential main groove 22. It is provided as a one-side open lug groove that terminates in the land portion 10 located between the two.

  Since the center lug groove 41 which is a one-side opening lug groove does not penetrate the adjacent circumferential main grooves 20, the land portion located between the adjacent center circumferential main grooves 21 and the shoulder circumferential main grooves 22. 10 is formed as a center rib 11 which is a rib-like land portion 10 extending in the tire circumferential direction without being divided in the tire circumferential direction. The center rib 11 is disposed at two locations on both sides in the tire width direction of the center circumferential main groove 21, and the inside in the tire width direction is partitioned by the center circumferential main groove 21, and the outside in the tire width direction is the shoulder. It is partitioned by the circumferential main groove 22. That is, the center ribs 11 are provided in two rows, and the two rows of center ribs 11 are arranged adjacent to each other via the center circumferential main groove 21.

  The center lug groove 41 is provided in the center rib 11 formed as described above. As the center lug groove 41, a first center lug groove 50 and a second center lug groove 60 are provided. Among these, the first center lug groove 50 has one end opening in the shoulder circumferential main groove 22 and the other end terminating in the center rib 11. The second center lug groove 60 has one end opened to the center circumferential main groove 21 and the other end terminated in the center rib 11.

  The first center lug groove 50 and the second center lug groove 60 are arranged in a staggered manner by alternately providing the first center lug groove 50 and the second center lug groove 60 in the tire circumferential direction. Arranged. In other words, the center lug groove 41 is alternately arranged with the first center lug groove 50 and the second center lug groove 60 in a predetermined direction in the tire circumferential direction, so that the shoulder circumferential main groove 22 is arranged. The center lug grooves 41 opening in the center and the center lug grooves 41 opening in the center circumferential main groove 21 are alternately arranged.

  Further, the center rib 11 is provided with a plurality of notches 90 that are located on the extension line of the end portion of the center lug groove 41 that terminates in the center rib 11 and that open to the circumferential main groove 20. Specifically, the notch 90 includes a first notch 91 that is a notch 90 that opens in the center circumferential main groove 21 and a second notch 95 that is a notch 90 that opens in the shoulder circumferential main groove 22. A plurality of them are provided. Among these, the 1st notch 91 is located on the extended line of the edge part 54 by the side of the 1st center lug groove 50 in the center rib 11, and the 2nd notch 95 is the 2nd center lug groove. 60 on the extension line of the end 64 on the side terminating in the center rib 11.

  The notch 90 referred to here is a recess formed by recessing from the tread surface 3 and having a width in the tire width direction of less than 5 mm. The center lug groove 41, that is, the lug groove 40 is the tire width. A width in the direction is 5 mm or more. Further, the notch 90 does not have to be located on the extended line of the end portions 54 and 64 on the side terminating in the center rib 11 of the center lug groove 41 in the entire notch 90. The notch 90 is formed in a circumferential main groove 20 that is different from the circumferential main groove 20 in which the center lug groove 41 is opened, out of the two circumferential main grooves 20 that define the center rib 11 in which the center lug groove 41 is provided. When the center lug groove 41 is extended toward the center lug groove 41, at least a part of the notch 90 only needs to be positioned within the range of the groove width of the center lug groove 41.

  The center lug grooves 41 and the notches 90 that open to the same circumferential main groove 20 are alternately arranged in the tire circumferential direction. In other words, the first center lug grooves 50 and the second notches 95 that open to the same shoulder circumferential main groove 22 are alternately arranged in the tire circumferential direction, and the first center lug grooves 50 that open to the same center circumferential main groove 21. The two center lug grooves 60 and the first notches 91 are alternately arranged in the tire circumferential direction.

  Further, as the first center lug groove 50 and the second center lug groove 60 are alternately provided in the tire circumferential direction, both the first notch 91 and the second notch 95 are directed in the tire circumferential direction. It is provided alternately. That is, the first notch 91 and the second notch 95 are similar to the first center lug groove 50 and the second center lug groove 60 in the tire circumferential direction. Are alternately arranged to form a staggered arrangement. Furthermore, the center lug grooves 41 and the notches 90, which are provided in plural, are arranged in a staggered manner, so that the center lug grooves 41 and the notches 90 are also arranged in a staggered manner. .

  The shoulder lug groove 42 is located outside the shoulder circumferential main groove 22 in the tire width direction, and penetrates the land portion 10 located outside the shoulder circumferential main groove 22 in the tire width direction in the tire width direction. ing. That is, the shoulder lug groove 42 has an inner end in the tire width direction that is open from the outer side in the tire width direction with respect to the shoulder circumferential main groove 22, and an outer end in the tire width direction is the shoulder portion 4. And is open toward the outside in the tire width direction.

  Since the shoulder lug groove 42 penetrates the land portion 10 located on the outer side in the tire width direction of the shoulder circumferential main groove 22 in the tire width direction in this way, the land on the outer side in the tire width direction of the shoulder circumferential main groove 22 is The portion 10 is partitioned as a shoulder block 12 by a shoulder circumferential main groove 22 and a shoulder lug groove 42. That is, the shoulder block 12 is provided as a shoulder land portion that is the land portion 10 that is located on the outer side in the tire width direction of the shoulder circumferential main groove 22, and the inner side in the tire width direction is partitioned by the shoulder circumferential main groove 22. Both sides in the tire circumferential direction are partitioned by shoulder lug grooves 42. A plurality of the shoulder blocks 12 formed in this manner are arranged in the tire circumferential direction. For this reason, the shoulder blocks 12 are arranged on the outer side in the tire width direction of the shoulder circumferential main grooves 22 in the tire circumferential direction. A shoulder block row 13 is arranged in a row. The shoulder block row 13 is disposed at two locations on the outer side in the tire width direction of the two shoulder circumferential main grooves 22 and is adjacent to the center rib 11 via the shoulder circumferential main grooves 22.

  Further, the shoulder lug groove 42 includes a first shoulder lug groove 70 and a second shoulder lug groove 80 having different groove depths. The groove depth of the first shoulder lug groove 70 is deeper than the groove depth of the second shoulder lug groove 80, and the first shoulder lug groove 70 and the second shoulder lug groove 80 are alternately arranged in the tire circumferential direction. It is installed. In this case, the comparison between the groove depths of the first shoulder lug groove 70 and the second shoulder lug groove 80 is an average depth obtained by weighting the groove depth by the groove area. Is a comparison. That is, the first shoulder lug groove 70 has a weighted average groove depth deeper than the weighted average groove depth of the second shoulder lug groove 80. Further, the weighted average groove depth of the first shoulder lug groove 70 is deeper than the weighted average groove depth of the first center lug groove 50 and the second center lug groove 60.

  The land portion 10 located on the outer side in the tire width direction of the shoulder circumferential main groove 22 is formed as a shoulder block 12 partitioned in the tire circumferential direction by a shoulder lug groove 42, whereas the shoulder circumferential main groove 22 The land portion 10 located on the inner side in the tire width direction is a center rib 11 continuous in the tire circumferential direction. That is, the center rib 11 in which the center lug groove 41 and the notch 90 are disposed is not formed with grooves and sipes that are open to the circumferential main groove 20 at both ends, and the land portion 10 extends in the tire width direction. The through lug groove 40 is formed only in the shoulder block row 13. On the contrary, the one side opening lug groove such as the center lug groove 41 and the notch 90 are not formed in the shoulder block 12, and the center lug groove 41 and the notch 90 which are one side opening lug grooves are the shoulder It is arranged in a staggered manner in the land 10 other than the block 12.

  FIG. 3 is a detailed view of part B of FIG. FIG. 4 is a detailed view of part C in FIG. The first center lug groove 50 formed in the center rib 11 and opened to the shoulder circumferential main groove 22 has a constant width portion 51 formed with a constant groove width and a widened portion 52 where the groove width changes. The widened portion 52 opens in the shoulder circumferential main groove 22. Among these, the constant width portion 51 is an end portion on the side that terminates in the center rib 11 in the first center lug groove 50 from the portion of the widened portion 52 on the side opposite to the side that opens in the shoulder circumferential main groove 22. 54 extends. Further, the widened portion 52 has a groove width substantially equal to the groove width of the constant width portion 51 at the position where the constant width portion 51 is connected, and the shoulder circumferential main groove from the constant width portion 51 side. The width of the groove increases toward the side opening at 22. A portion of the widened portion 52 formed as described above that opens to the shoulder circumferential main groove 22 is an opening 53 with respect to the shoulder circumferential main groove 22 in the first center lug groove 50.

  Similar to the first center lug groove 50, the second center lug groove 60 formed in the center rib 11 and opened to the center circumferential main groove 21 includes a constant width portion 61 having a constant groove width, and a groove width. And the widened portion 62 is open to the center circumferential direction main groove 21. Among these, the constant width portion 61 is an end portion on the side terminating in the center rib 11 in the second center lug groove 60 from a portion of the widened portion 62 on the side opposite to the side opening in the center circumferential main groove 21. It extends to 64. Further, the widened portion 62 has a groove width that is substantially the same as the groove width of the constant width portion 61 at the position where the constant width portion 61 is connected, and the center circumferential direction main groove from the constant width portion 61 side. The width of the groove becomes larger toward the side opening at 21. A portion of the widened portion 62 formed as described above that opens to the center circumferential main groove 21 is an opening 63 of the second center lug groove 60 with respect to the center circumferential main groove 21.

  The center lug groove 41 formed as described above has a length L1 in the tire width direction of the center lug groove 41 with respect to a width W1 in the tire width direction of the center rib 11 in which the center lug groove 41 is disposed. It is in the range of 0.3 ≦ (L1 / W1) ≦ 0.6. That is, in the first center lug groove 50, the ratio of the length L1 of the first center lug groove 50 in the tire width direction to the width W1 of the center rib 11 in the tire width direction is 0.3 or more and 0.6 or less. The ratio of the length L1 of the second center lug groove 60 in the tire width direction to the width W1 of the center rib 11 in the tire width direction of the second center lug groove 60 is also 0.3 or more and 0.6 or less.

  The first center lug groove 50 has a length L3 of the constant width portion 51 in the tire width direction of 0.6 ≦ (L3 / L1) with respect to a length L1 of the first center lug groove 50 in the tire width direction. ) ≦ 0.8. Similarly, the length L3 of the constant width portion 61 in the tire width direction of the second center lug groove 60 is 0.6 ≦ (L3 / L1) with respect to the length L1 of the second center lug groove 60 in the tire width direction. ) ≦ 0.8.

  Further, in the first center lug groove 50, the relationship between the groove width W5 at the position opened in the circumferential main groove 20 in the widened portion 52 and the groove width W4 of the constant width portion 51 is 0.4 ≦ ( W4 / W5) ≦ 0.6, and the second center lug groove 60 also has a groove width W5 at a position opened in the circumferential main groove 20 in the widened portion 62 and a constant width portion 61. The groove width W4 is in a range of 0.4 ≦ (W4 / W5) ≦ 0.6. In this case, the groove width W4 of the constant width portions 51 and 61 is the distance between the opposing groove walls in the direction orthogonal to the groove walls of the constant width portions 51 and 61. Further, the groove width W5 at the position where the widened portions 52 and 62 are opened in the circumferential main groove 20 is the opening 53 of the first center lug groove 50 and the second center lug groove 60 with respect to the circumferential main groove 20. The width in the tire circumferential direction is 63.

  The first center lug groove 50 is preferably formed so that the groove width of the constant width portion 51 is in the range of 3 mm to 8 mm and the groove depth of the constant width portion 51 is in the range of 1 mm to 5 mm. . The second center lug groove 60 is also preferably formed so that the groove width of the constant width portion 61 is in the range of 3 mm to 8 mm and the groove depth of the constant width portion 61 is in the range of 1 mm to 5 mm.

  Further, the notch 90 formed in the center rib 11 has a width in the tire circumferential direction as it approaches the circumferential main groove 20 from a position away from the circumferential main groove 20 in which the notch 90 opens in the tire width direction. It is formed in a trapezoidal shape that becomes larger. That is, the first notch 91 that opens in the center circumferential main groove 21 has a width in the tire circumferential direction as it approaches the center circumferential main groove 21 from a position away from the center circumferential main groove 21 in the tire width direction. And an end portion 92 located on the side opposite to the side opening in the center circumferential main groove 21 in the tire width direction is formed along the tire circumferential direction. Similarly, the second notch 95 that opens in the shoulder circumferential main groove 22 increases in the tire circumferential direction as it approaches the shoulder circumferential main groove 22 from a position away from the shoulder circumferential main groove 22 in the tire width direction. The width is increased, and an end portion 96 is formed along the tire circumferential direction, which is located on the opposite side of the tire circumferential direction main groove 22 in the tire width direction.

  The cutout 90 formed in this way is formed in substantially the same shape as the widened portion 52 of the first center lug groove 50 and the widened portion 62 of the second center lug groove 60. That is, the notch 90 and the widened portions 52 and 62 have the same width in the tire circumferential direction and the width in the tire width direction, and the depth in the tire radial direction is also the same depth. ing.

  Further, the notch 90 has a length L2 in the tire width direction of the notch 90 in the tire width direction of the center rib 11 in which the notch 90 is disposed, and 0.05 ≦ (L2 / W1). ) ≦ 0.20. That is, in the first notch 91, the ratio of the length L2 of the first notch 91 in the tire width direction to the width W1 of the center rib 11 in the tire width direction is 0.05 or more and 0.20 or less. The ratio of the length L2 of the second notch 95 in the tire width direction to the width W1 of the center rib 11 in the tire width direction of the two notches 95 is 0.05 or more and 0.20 or less.

  Further, in the notch 90, the relationship between the minimum width W2 and the maximum width W3 in the tire circumferential direction is 0.4 ≦ (W2 / W3) ≦ 0 in both the first notch 91 and the second notch 95. Within the range of .6. In the present embodiment, since the notch 90 has a trapezoidal shape, the minimum width W2 of the first notch 91 is the tire circumference of the end 92 on the opposite side of the side that opens to the center circumferential main groove 21. The maximum width W3 of the first notch 91 is the width in the tire circumferential direction of the portion opened to the center circumferential main groove 21. The same applies to the second notch 95, and the minimum width W2 of the second notch 95 is the width in the tire circumferential direction of the end portion 96 on the opposite side of the side opening to the shoulder circumferential main groove 22, The maximum width W <b> 3 of the two notches 95 is the width in the tire circumferential direction of the portion opened to the shoulder circumferential main groove 22.

  5 is a cross-sectional view taken along line EE in FIG. The first center lug groove 50 has a groove depth that is greatly different between the constant width portion 51 and the widened portion 52, and the groove depth of the widened portion 52 is deeper than the groove depth of the constant width portion 51. ing. Specifically, in the first center lug groove 50, the minimum groove depth D1 of the constant width portion 51 is 0.2 ≦ (D1 / D2) ≦ 0. It is within the range of 5.

  Further, the widened portion 52 of the first center lug groove 50 has a groove depth similar to the groove depth of the shoulder circumferential main groove 22, and the maximum groove depth D2 of the widened portion 52 is the widened width. It is in the range of 0.8 ≦ (D2 / DC) ≦ 1.0 with respect to the groove depth DC of the shoulder circumferential main groove 22 where the portion 52 opens.

  6 is a cross-sectional view taken along line FF in FIG. The second center lug groove 60 also has a groove depth that is greatly different between the constant width portion 61 and the wide width portion 62, and the groove depth of the wide width portion 62 is deeper than the groove depth of the constant width portion 61. ing. Specifically, in the second center lug groove 60, the minimum groove depth D1 of the constant width portion 61 is 0.2 ≦ (D1 / D2) ≦ 0. It is within the range of 5.

  Further, the widened portion 62 of the second center lug groove 60 has a groove depth similar to that of the center circumferential main groove 21, and the maximum groove depth D2 of the widened portion 62 is the widened width. With respect to the groove depth DC of the center circumferential main groove 21 in which the portion 62 is open, the range is 0.8 ≦ (D2 / DC) ≦ 1.0.

  FIG. 7 is a detailed view of a portion G in FIG. The first shoulder lug groove 70 has a constant width portion 71 formed with a constant groove width and a widening in which the groove width is changed by bending the groove wall near the center in the length direction of the first shoulder lug groove 70. Part 72. Similarly, in the second shoulder lug groove 80, the groove wall is bent near the center in the length direction of the second shoulder lug groove 80, so that the constant width portion 81 formed with a constant groove width and the groove width change. And a widened portion 82. In both the first shoulder lug groove 70 and the second shoulder lug groove 80, the constant width portions 71, 81 are located inside the wide width portions 72, 82 in the tire width direction, and the wide width portions 72, 82 are constant width portions. 71 and 81 are located outside in the tire width direction. That is, in the first shoulder lug groove 70 and the second shoulder lug groove 80, the constant width portions 71 and 81 open into the shoulder circumferential main groove 22, and the widened portions 72 and 82 are on the shoulder portion 4 on the outer side in the tire width direction. It is open toward.

  FIG. 8 is a detailed view of a portion H in FIG. The constant width portion 71 of the first shoulder lug groove 70 is a tire from an inner opening 74 that is an opening portion of the first shoulder lug groove 70 to the shoulder circumferential main groove 22 to the vicinity of the center of the shoulder block 12 in the tire width direction. It extends toward the outside in the width direction. In the present embodiment, the constant width portion 71 of the first shoulder lug groove 70 is inclined in the tire circumferential direction while extending in the tire width direction, and the inner opening 74 is chamfered.

  The widened portion 72 of the first shoulder lug groove 70 extends from the end of the constant width portion 71 on the outer side in the tire width direction toward the outer side in the tire width direction. That is, the groove wall of the first shoulder lug groove 70 has a bent portion 73 near the center of the shoulder block 12 in the tire width direction, and the widened portion 72 is formed to extend outward from the bent portion 73 in the tire width direction. Has been. The widened portion 72 has a groove width that is the same as the groove width of the constant width portion 71 at the position of the bent portion 73 that is a boundary position with the constant width portion 71, and extends from the inside to the outside in the tire width direction. The groove width increases as you go. That is, the bent portion 73 is at a position where the groove width of the first shoulder lug groove 70 changes, and the first shoulder lug groove 70 is formed with a constant groove width from the bent portion 73 to the inside in the tire width direction. From the bent portion 73 to the outer side in the tire width direction, the groove width becomes wider toward the outer side in the tire width direction. In addition, the bending part 73 may be formed in both the groove walls which the 1st shoulder lug groove 70 opposes, and may be formed only in one groove wall of the opposing groove wall.

  Since the first shoulder lug groove 70 has the constant width portion 71 and the widened portion 72 as described above, the first shoulder lug groove 70 has a tire width direction rather than a groove width at a position near the center of the first shoulder lug groove 70 in the tire width direction. The groove width at the position of the outer end is larger. Specifically, in the portion located in the measurement region AM that is in the range of 40% to 60% of the width WB of the shoulder block 12 in the tire width direction from one end portion of the first shoulder lug groove 70 in the tire width direction. The narrow groove width is defined as the minimum groove width W11, and the groove width at the outer end of the first shoulder lug groove 70 in the tire width direction is defined as the groove width W12. In this case, in the first shoulder lug groove 70, the relationship between the minimum groove width W11 and the groove width W12 is in the range of 1.3 ≦ (W12 / W11) ≦ 1.7.

  That is, in the first shoulder lug groove 70, the bent portion 73 that is the boundary position between the constant width portion 71 and the widened portion 72 is located in the measurement region AM, and the minimum groove width W11 is located in the measurement region AM. This is the groove width of the constant width portion 71. Further, the groove width W12 at the outer end in the tire width direction of the first shoulder lug groove 70 is the portion of the outer opening 75 that is the portion of the widened portion 72 that opens toward the outer side in the tire width direction at the shoulder 4. Groove width. In the first shoulder lug groove 70, the ratio of the groove width W12 of the outer opening 75 to the minimum groove width W11 is in the range of 1.3 or more and 1.7 or less.

  The minimum groove width W11 of the first shoulder lug groove 70 is preferably in the range of 4 mm or more and 8 mm or less, and the groove width W12 at the outer end in the tire width direction of the first shoulder lug groove 70 is 6 mm or more. It is preferably within a range of 12 mm or less.

  FIG. 9 is a detailed view of a portion J in FIG. Similarly to the first shoulder lug groove 70, the second shoulder lug groove 80 has a constant width portion 81 inside the second shoulder lug groove 80 that is an opening portion of the second shoulder lug groove 80 to the shoulder circumferential main groove 22. From the opening 84 to the vicinity of the center of the shoulder block 12 in the tire width direction, it extends toward the outer side in the tire width direction while being inclined in the tire circumferential direction. The second shoulder lug groove 80 also has a bent portion 83 in the vicinity of the center of the shoulder block 12 in the tire width direction of the groove wall, and the widened portion 82 is formed to extend outward from the bent portion 83 in the tire width direction. Has been. The widened portion 82 has a groove width that is the same as the groove width of the constant width portion 81 at the position of the bent portion 83 that is a boundary position with the constant width portion 81, and extends from the inside to the outside in the tire width direction. The groove width increases as you go. That is, the bent portion 83 is at a position where the groove width of the second shoulder lug groove 80 changes, and the second shoulder lug groove 80 is formed with a constant groove width on the inner side in the tire width direction from the bent portion 83, From the bent portion 83 to the outer side in the tire width direction, the groove width becomes wider toward the outer side in the tire width direction. In addition, the bent portion 83 of the second shoulder lug groove 80 may be formed on both the opposing groove walls of the second shoulder lug groove 80 as well as the bent portion 73 of the first shoulder lug groove 70. It may be formed only on one groove wall of the groove wall.

  Similarly to the first shoulder lug groove 70, the second shoulder lug groove 80 also has a constant width portion 81 and an enlarged width portion 82, so that the groove width at a position near the center of the second shoulder lug groove 80 in the tire width direction. The groove width at the position of the outer end portion in the tire width direction is larger than that. Specifically, in the portion located in the measurement area AM that is in the range of 40% to 60% of the width WB of the shoulder block 12 in the tire width direction from one end portion of the second shoulder lug groove 80 in the tire width direction. The narrow groove width is defined as the minimum groove width W21, and the groove width at the outer end in the tire width direction of the second shoulder lug groove 80 is defined as the groove width W22. In this case, in the second shoulder lug groove 80, the relationship between the minimum groove width W21 and the groove width W22 is in a range of 1.1 ≦ (W22 / W21) ≦ 1.5.

  That is, in the second shoulder lug groove 80, the bent portion 83 that is the boundary position between the constant width portion 81 and the widened portion 82 is located in the measurement region AM, and the minimum groove width W21 is located in the measurement region AM. The groove width of the constant width portion 81 is as follows. Further, the groove width W22 at the end portion of the second shoulder lug groove 80 on the outer side in the tire width direction is the width of the outer opening portion 85 that is the portion of the widened portion 82 that opens toward the outer side in the tire width direction at the shoulder portion 4. Groove width. In the second shoulder lug groove 80, the ratio of the groove width W22 of the outer opening 85 to the minimum groove width W21 is in the range of 1.1 to 1.5.

  The minimum groove width W21 of the second shoulder lug groove 80 is preferably in the range of 4 mm or more and 8 mm or less, and the groove width W22 at the outer end in the tire width direction of the second shoulder lug groove 80 is 5 mm or more. It is preferably within a range of 10 mm or less.

  Further, the first shoulder lug groove 70 and the second shoulder lug groove 80 have a groove width in the outer opening 75 of the first shoulder lug groove 70 that is greater than the groove width W22 in the outer opening 85 of the second shoulder lug groove 80. W12 is larger. Specifically, the first shoulder lug groove 70 and the second shoulder lug groove 80 are the groove width W12 in the outer opening 75 of the first shoulder lug groove 70 and the groove width in the outer opening 85 of the second shoulder lug groove 80. The relationship with W22 is in the range of 1.1 ≦ (W12 / W22) ≦ 1.3.

  The first shoulder lug groove 70 and the second shoulder lug groove 80 are different in weighted average groove depth from each other, and the first shoulder lug groove 70 has a load average groove depth greater than that of the second shoulder lug groove 80. The weighted average groove depth is deeper. That is, the first shoulder lug groove 70 and the second shoulder lug groove 80 are different from each other in the form of the groove bottom of the first shoulder lug groove 70 and the form of the groove bottom of the second shoulder lug groove 80. The weighted average groove depths are different from each other.

  Specifically, the second shoulder lug groove 80 has a substantially constant groove depth from the inner opening 84 side to the outer opening 85 side, whereas the first shoulder lug groove 70 has an inner side. The groove depth is deeper on the outer opening 75 side than on the opening 74 side. More specifically, the first shoulder lug groove 70 has a substantially constant groove depth from the position of the inner opening 74 to a predetermined position on the outer side in the tire width direction, and the tire width from the predetermined position. The groove depth increases toward the outside in the direction. The first shoulder lug groove 70 has, for example, a substantially constant groove depth in the tire width direction inner region from the vicinity of the center of the width of the first shoulder lug groove 70 in the tire width direction. In the region on the outer side in the tire width direction from the vicinity of the center of the width of the one shoulder lug groove 70, the groove depth increases toward the outer side in the tire width direction.

  FIG. 10 is an explanatory diagram of the outer regions of the first shoulder lug groove 70 and the second shoulder lug groove 80. The first shoulder lug groove 70 has a groove depth closer to the outer opening 75 than a groove depth closer to the inner opening 74, whereas the second shoulder lug groove 80 has a greater depth. Regardless of the position in the tire width direction, the groove depth is substantially constant. For this reason, the first shoulder lug groove 70 and the second shoulder lug groove 80 are greatly different in depth at a position closer to the outer side in the tire width direction. Specifically, when the groove depth of the outer region A11 of the first shoulder lug groove 70 is D11 and the groove depth of the outer region A21 of the second shoulder lug groove 80 is D21, the first shoulder lug groove 70 is. The relationship between the groove depth D11 and the groove depth D21 of the second shoulder lug groove 80 is in the range of 0.2 ≦ (D21 / D11) ≦ 0.5.

  In this case, the outer region A11 of the first shoulder lug groove 70 extends from the position of the bent portion 73 in the first shoulder lug groove 70 to the outer end in the tire width direction of the first shoulder lug groove 70, that is, the outer opening 75. It is an area. Similarly, the outer region A21 of the second shoulder lug groove 80 extends from the position of the bent portion 83 in the second shoulder lug groove 80 to the outer end in the tire width direction of the second shoulder lug groove 80, that is, the outer opening 85. It is an area. Further, the groove depth D11 of the first shoulder lug groove 70 in the outer region A11 of the first shoulder lug groove 70 is a groove depth obtained by weighted averaging the groove depths of the first shoulder lug groove 70 in the outer region A11. Yes. Similarly, the groove depth D21 of the second shoulder lug groove 80 in the outer region A21 of the second shoulder lug groove 80 is a groove depth obtained by weighted averaging the groove depths of the second shoulder lug groove 80 in the outer region A21. ing.

  As described above, the groove depth of the second shoulder lug groove 80 is substantially constant, whereas the groove depth of the first shoulder lug groove 70 differs depending on the position in the tire width direction. At a position near the portion 4, the groove depth is deeper than the groove depth of the second shoulder lug groove 80.

  As for the 1st center lug groove 50 formed in the center rib 11, the minimum groove depth D1 of the fixed width part 51 is 0.8 <= with respect to the groove depth D21 of the outer side area | region A21 of the 2nd shoulder lug groove 80. (D1 / D21) ≦ 1.2. Similarly, in the second center lug groove 60, the minimum groove depth D1 of the constant width portion 61 is 0.8 ≦ (D1 / D21) with respect to the groove depth D21 of the outer region A21 of the second shoulder lug groove 80. It is within the range of ≦ 1.2. In other words, the first center lug groove 50 and the second center lug groove 60 have the groove depths of the constant width portions 51 and 61 that are approximately the same as the groove depth of the second shoulder lug groove 80.

  FIG. 11 is an explanatory diagram showing the relationship between the distance between the adjacent first center lug grooves 50 and the constant width portion 51. FIG. 12 is an explanatory diagram showing the relationship between the distance between the adjacent second center lug grooves 60 and the constant width portion 61. The center lug groove 41 is a constant width portion of the first center lug groove 50 when the distance in the tire circumferential direction between the center lug grooves 41 that are opened in the same circumferential main groove 20 and are adjacent to each other in the tire circumferential direction is LC. The width W6 in the tire circumferential direction 51 and the width W6 in the tire circumferential direction of the constant width portion 61 of the second center lug groove 60 are 0.05 ≦ (W6 / LC) ≦ 0.15, respectively, with respect to the distance LC. It is within the range. That is, the first center lug groove 50 has a width W6 in the tire circumferential direction of the constant width portion 51 of the first center lug groove 50 with respect to a distance LC in the tire circumferential direction between the first center lug grooves 50 adjacent in the tire circumferential direction. Is in the range of 0.05 to 0.15. Similarly, in the second center lug groove 60, the width W6 in the tire circumferential direction of the constant width portion 61 of the second center lug groove 60 with respect to the distance LC in the tire circumferential direction between the second center lug grooves 60 adjacent to each other in the tire circumferential direction. Is in the range of 0.05 to 0.15.

  FIG. 13 is an explanatory view of the relative positional relationship between the center lug groove 41 and the notch 90 provided in the land portion 10 adjacent to each other via the circumferential main groove 20. The center lug grooves 41 and the notches 90 respectively disposed in two rows of center ribs 11 adjacent to each other via the center circumferential main groove 21 are disposed within a predetermined range between the center ribs 11. Yes. Specifically, of the two rows of center ribs 11 adjacent to each other via the center circumferential main groove 21, each center rib 11 is disposed in the center circumferential main groove 21 and opens in the tire circumferential direction. The distance in the tire circumferential direction between the adjacent second center lug groove 60 and the first notch 91 is L4, and is disposed in the other center rib 11 to open in the center circumferential main groove 21 and in the tire circumferential direction. Is located between the second center lug groove 60 and the first notch 91 that defines the distance L4, and the second center lug that defines the distance L4. Of the distances between the grooves 60 and the first notches 91 in the tire circumferential direction, when the shorter distance is L5, the relationship between the distance L4 and the distance L5 is 0.4 ≦ (L5 / L4). ≦ Which is within the range of .5.

  In other words, the second center lug groove 60 that defines the distance L4 and the first notch 91 are disposed on the center rib 11 different from the center rib 11, and the position in the tire circumferential direction defines the distance L4. When the second center lug groove 60 and the first notch 91 are located between the second center lug groove 60 and the first notch 91 is the second center lug groove 60 (FIG. 13). Reference) is a distance in the tire circumferential direction between the second center lug groove 60 and the second center lug groove 60 that defines the distance L4, and a first cut that defines the distance L4 from the second center lug groove 60. Of the distances between the notch 91 and the tire circumferential direction, the shorter distance is L5.

  Further, the second center lug groove 60 that defines the distance L4 and the first notch 91 are disposed on the center rib 11 different from the center rib 11, and the position in the tire circumferential direction defines the distance L4. When the first notch 91 of the second center lug groove 60 and the first notch 91 is located between the second center lug groove 60 and the first notch 91 (not shown) Is the distance in the tire circumferential direction between the first notch 91 and the second center lug groove 60 that defines the distance L4, and the first notch 91 and the first notch 91 that defines the distance L4 and the tire. Of the distances in the circumferential direction, the shorter distance is L5.

  In this case, the distance L4 between the second center lug groove 60 and the first notch 91 is the center position in the tire circumferential direction of the portion having the maximum width W3 of the first notch 91, that is, the first notch 91. The tire circumferential direction between the center position in the tire circumferential direction of the opening portion to the center circumferential main groove 21 and the position where the center line of the constant width portion 61 of the second center lug groove 60 intersects the center circumferential main groove 21 It has become a distance. The same applies to the distance L5, and the position of the second center lug groove 60 is indicated by the position where the center line of the constant width portion 61 of the second center lug groove 60 intersects the center circumferential main groove 21, and the first notch The position 91 is indicated by the center position in the tire circumferential direction of the opening to the center circumferential main groove 21 in the first notch 91.

  FIG. 14 is an explanatory view of the relative positional relationship among the center lug groove 41, the notch 90, and the shoulder lug groove 42 provided in the land portion 10 adjacent via the shoulder circumferential main groove 22. A shoulder lug groove 42 defining the shoulder block 12 together with the shoulder circumferential main groove 22 and a center lug groove 41 provided in the adjacent center rib 11 via the shoulder circumferential main groove 22 and opening to the shoulder circumferential main groove 22. And the notch 90 is arrange | positioned in the predetermined range.

  Specifically, the tire circumference of the first center lug groove 50 and the second notch 95 which are disposed in the center rib 11 adjacent to the shoulder block 12 via the shoulder circumferential main groove 22 and adjacent in the tire circumferential direction. A shoulder lug groove 42 positioned between the first center lug groove 50 and the second notch 95, wherein the distance in the direction is L4, and the position in the tire circumferential direction of the plurality of shoulder lug grooves 42 defines the distance L4; Of the distances in the tire circumferential direction between the first center lug groove 50 and the second notch 95 that define the distance L4, when the shorter distance is L6, the relationship between the distance L4 and the distance L6 is: 0.4 ≦ (L6 / L4) ≦ 0.5.

  That is, when the first shoulder lug groove 70 is located between the positions in the tire circumferential direction of the first center lug groove 50 and the second notch 95 that define the distance L4, the distance L6 is equal to the first center lug. The distance in the tire circumferential direction between the groove 50 or the second notch 95 and the first shoulder lug groove 70 in the tire circumferential direction, and the position in the tire circumferential direction of the first center lug groove 50 and the second notch 95 defining the distance L4 When the second shoulder lug groove 80 is located between the distance L6, the distance L6 is the distance between the first center lug groove 50 or the second notch 95 and the second shoulder lug groove 80 in the tire circumferential direction.

  Note that the position of the shoulder lug groove 42 in this case is indicated by the position in the tire circumferential direction of the intersection of the center line of the shoulder width of the shoulder lug groove 42 and the shoulder circumferential main groove 22 without considering chamfering. That is, the position of the shoulder lug groove 42 is indicated by a position where the center lines of the constant width portions 71 and 81 of the shoulder lug groove 42 intersect the shoulder circumferential main groove 22.

  The pneumatic tire 1 according to the present embodiment configured as described above is used for a heavy-duty pneumatic tire. When the pneumatic tire 1 is mounted on the vehicle, the pneumatic tire 1 is mounted on the vehicle in a rim-assembled and inflated state. The pneumatic tire 1 in a state where the rim is assembled to the rim wheel is used by being mounted on a large vehicle as compared with a passenger car such as a truck or a bus.

  When the vehicle equipped with the pneumatic tire 1 travels, the pneumatic tire 1 rotates while the tread surface 3 positioned below the tread surface 3 is in contact with the road surface. When driving on a dry road surface with a vehicle equipped with pneumatic tires 1, the driving force or braking force is transmitted to the road surface or the turning force is generated mainly by the frictional force between the tread surface 3 and the road surface. To drive. Further, when traveling on a wet road surface, water between the tread surface 3 and the road surface enters the circumferential main groove 20 and the lug groove 40, and water between the tread surface 3 and the road surface is discharged by these grooves. Drive while discharging. As a result, the tread surface 3 is easily grounded to the road surface, and the vehicle can travel by the frictional force between the tread surface 3 and the road surface.

  The groove formed in the tread surface 3 contributes to the running performance on the wet road surface by draining the water between the tread surface 3 and the road surface in this way, but the groove formed in the tread surface 3 is In addition, since the sound generated in the ground contact area with the road surface on the tread surface 3 is also transmitted to other than the ground contact area, it also causes noise. In particular, the lug groove 40 extending in the tire width direction transmits a sound generated in the ground contact area to the outside in the tire width direction, so that a so-called passing sound that is emitted from the ground contact area toward the tire width direction outside when the vehicle is running is large. It also becomes a cause.

  On the other hand, in the present embodiment, the center lug groove 41 is formed as a one-sided open lug groove having one end opened in the circumferential main groove 20 and the other end terminated in the land portion 10. It is possible to suppress the sound generated in the ground contact region from flowing outward through the center lug groove 41 in the tire width direction. Thereby, since the passing sound can be reduced, it is possible to reduce the noise during traveling of the vehicle.

  The center rib 11 in which the center lug groove 41 is formed is provided with a notch 90 that is located on the extension line of the center lug groove 41 and opens into the circumferential main groove 20. Is arranged in a staggered manner, so that drainage at any position of the center rib 11 in the tire width direction can be secured, and an edge component can be secured by the center lug groove 41 and the notch 90. . Thereby, the traction performance at the time of driving | running | working on the wet road surface is securable. As a result, it is possible to reduce noise while ensuring wet performance.

  The center lug groove 41 has a length L1 in the tire width direction of the center lug groove 41 of 0.3 ≦ (L1 / W1) ≦ 0.6 with respect to the width W1 of the center rib 11 in the tire width direction. Since it is within the range, the drainage at the center lug groove 41 can be ensured while reducing the sound when the vicinity of the center lug groove 41 in the center rib 11 is grounded. That is, when the length L1 of the center lug groove 41 in the tire width direction is (L1 / W1) <0.3 with respect to the width W1 of the center rib 11, the length L1 of the center lug groove 41 is short. There is a risk of passing. In this case, it becomes difficult to ensure drainage by the center lug groove 41, and it may be difficult to ensure wet performance. When the length L1 of the center lug groove 41 in the tire width direction is (L1 / W1)> 0.6 with respect to the width W1 of the center rib 11, the length L1 of the center lug groove 41 is long. There is a risk of passing. In this case, the hitting sound at the time of ground contact at the position where the center lug groove 41 is formed in the center rib 11 may be increased, and it may be difficult to reduce the noise.

  On the other hand, when the length L1 of the center lug groove 41 in the tire width direction is within the range of 0.3 ≦ (L1 / W1) ≦ 0.6 with respect to the width W1 of the center rib 11, The water drainage at the center lug groove 41 can be ensured while suppressing the hitting sound at the time of ground contact at the position where the lug groove 41 is formed. As a result, it is possible to reduce noise while ensuring wet performance more reliably.

  The notch 90 has a length L2 in the tire width direction of the notch 90 within a range of 0.05 ≦ (L2 / W1) ≦ 0.20 with respect to the width W1 of the center rib 11 in the tire width direction. Therefore, the notch 90 ensures wet traction, which is the traction performance when traveling on a wet road surface, while reducing the sound when the vicinity where the notch 90 is formed in the center rib 11 is grounded. Can do. That is, when the length L2 of the notch 90 in the tire width direction is (L2 / W1) <0.05 with respect to the width W1 of the center rib 11 in the tire width direction, the length L2 of the notch 90 May be too short. In this case, the edge component of the notch 90 becomes too small, and it may be difficult to ensure traction on a wet road surface. Further, when the length L2 of the notch 90 in the tire width direction is (L2 / W1)> 0.20 with respect to the width W1 of the center rib 11 in the tire width direction, the length L2 of the notch 90 May be too long. In this case, the hitting sound at the time of ground contact at the position where the notch 90 is formed in the center rib 11 is increased, and it may be difficult to reduce the noise.

  On the other hand, when the length L2 of the notch 90 in the tire width direction is within the range of 0.05 ≦ (L2 / W1) ≦ 0.20 with respect to the width W1 of the center rib 11, the notch The wet traction can be ensured by the notch 90 while suppressing the hitting sound at the time of ground contact at the position where the 90 is formed. As a result, it is possible to reduce noise while ensuring wet performance more reliably.

  Further, the notch 90 has a notch 90 in the center rib 11 because the relationship between the minimum width W2 and the maximum width W3 in the tire circumferential direction is within a range of 0.4 ≦ (W2 / W3) ≦ 0.6. It is possible to ensure wet traction by the notch 90 while reducing the sound generated when the vicinity of the surface is grounded. That is, if the relationship between the minimum width W2 and the maximum width W3 of the notch 90 is (W2 / W3) <0.4, the minimum width W2 of the notch 90 may be too small. In this case, the notch 90 may make it difficult to ensure wet traction. Further, when the relationship between the minimum width W2 and the maximum width W3 of the notch 90 is (W2 / W3)> 0.6, the minimum width W2 of the notch 90 may be too large. In this case, the hitting sound at the time of ground contact at the position where the notch 90 is formed in the center rib 11 is increased, and it may be difficult to reduce the noise.

  On the other hand, when the relationship between the minimum width W2 and the maximum width W3 of the notch 90 is within the range of 0.4 ≦ (W2 / W3) ≦ 0.6, the position of the notch 90 is formed. It is possible to ensure wet traction by the notch 90 while suppressing the hitting sound at the time of grounding. As a result, it is possible to reduce noise while ensuring wet performance more reliably.

  Further, in the center lug groove 41, the relationship between the groove width W5 at the position opened to the circumferential main groove 20 in the widened portions 52 and 62 and the groove width W4 of the constant width portions 51 and 61 is 0.4. Since it is within the range of ≦ (W4 / W5) ≦ 0.6, the drainage performance in the center lug groove 41 is reduced while reducing the sound when the vicinity of the center lug groove 41 in the center rib 11 is grounded. Can be secured. That is, the relationship between the groove width W5 of the center lug groove 41 at the position where the widened portions 52 and 62 open in the circumferential main groove 20 and the groove width W4 of the constant width portions 51 and 61 is (W4 / If W5) <0.4, the groove width W4 of the constant width portions 51 and 61 may be too small. In this case, it becomes difficult to ensure drainage by the center lug groove 41, and it may be difficult to ensure wet performance. Further, the relationship between the groove width W5 of the center lug groove 41 at the position where the widened portions 52 and 62 are opened in the circumferential main groove 20 and the groove width W4 of the constant width portions 51 and 61 is (W4 / When W5)> 0.6, the groove width W4 of the constant width portions 51 and 61 may be too large. In this case, the hitting sound at the time of ground contact at the position where the center lug groove 41 is formed in the center rib 11 may be increased, and it may be difficult to reduce the noise.

  On the other hand, the relationship between the groove width W5 of the center lug groove 41 at the position where the widened portions 52 and 62 are opened in the circumferential main groove 20 and the groove width W4 of the constant width portions 51 and 61 is 0. When it is within the range of 4 ≦ (W4 / W5) ≦ 0.6, the drainage performance at the center lug groove 41 is ensured while suppressing the hitting sound at the time of ground contact at the position where the center lug groove 41 is formed. be able to. As a result, it is possible to reduce noise while ensuring wet performance more reliably.

  Further, the center lug groove 41 has a length L3 in the tire width direction of the constant width portions 51 and 61 with respect to the length L1 of the center lug groove 41 in the tire width direction, 0.6 ≦ (L3 / L1) ≦. Since it exists in the range of 0.8, the drainage property in the center lug groove 41 can be ensured, reducing the sound when the vicinity where the center lug groove 41 is formed in the center rib 11 is grounded. That is, when the length L3 of the constant width portions 51 and 61 in the tire width direction is (L3 / L1) <0.6 with respect to the length L1 of the center lug groove 41, the tires of the widened portions 52 and 62 There is a possibility that the length in the width direction becomes too large. In this case, the hitting sound at the time of ground contact at the position where the center lug groove 41 is formed in the center rib 11 may be increased, and it may be difficult to reduce the noise. When the length L3 of the constant width portions 51 and 61 in the tire width direction is (L3 / L1)> 0.8 with respect to the length L1 of the center lug groove 41, the tires of the widened portions 52 and 62 There is a possibility that the length in the width direction becomes too small. In this case, it becomes difficult to ensure drainage by the center lug groove 41, and it may be difficult to ensure wet performance.

  On the other hand, the length L3 in the tire width direction of the constant width portions 51 and 61 of the center lug groove 41 is 0.6 ≦ (L3 / L1) ≦ 0.8 with respect to the length L1 of the center lug groove 41. When it is within the range, it is possible to ensure drainage performance in the center lug groove 41 while suppressing the hitting sound at the time of ground contact at the position where the center lug groove 41 is formed. As a result, it is possible to reduce noise while ensuring wet performance more reliably.

  In the center lug groove 41, the minimum groove depth D1 of the constant width portions 51 and 61 is 0.2 ≦ (D1 / D2) ≦ 0.5 with respect to the maximum groove depth D2 of the wide width portions 52 and 62. Therefore, the drainage at the center lug groove 41 can be ensured while reducing the sound when the vicinity of the center lug groove 41 in the center rib 11 is grounded. That is, when the minimum groove depth D1 of the constant width portions 51, 61 is (D1 / D2) <0.2 with respect to the maximum groove depth D2 of the wide width portions 52, 62, the constant width portions 51, 61 The minimum groove depth D1 may be too shallow. In this case, it becomes difficult to ensure drainage by the center lug groove 41, and it may be difficult to ensure wet performance. When the minimum groove depth D1 of the constant width portions 51, 61 is (D1 / D2)> 0.5 with respect to the maximum groove depth D2 of the wide width portions 52, 62, the constant width portions 51, 61 The minimum groove depth D1 may be too deep. In this case, the hitting sound at the time of ground contact at the position where the center lug groove 41 is formed in the center rib 11 may be increased, and it may be difficult to reduce the noise.

  In contrast, the minimum groove depth D1 of the constant width portions 51 and 61 of the center lug groove 41 is 0.2 ≦ (D1 / D2) ≦ 0.5 with respect to the maximum groove depth D2 of the widened portions 52 and 62. If it is within the range, it is possible to ensure drainage performance in the center lug groove 41 while suppressing the hitting sound at the time of ground contact at the position where the center lug groove 41 is formed. As a result, it is possible to reduce noise while ensuring wet performance more reliably.

  Further, the center lug groove 41 has a maximum groove depth D2 of the widened portions 52, 62 with respect to a groove depth DC of the circumferential main groove 20 in which the widened portions 52, 62 are open. DC) Within the range of ≦ 1.0, it is possible to ensure drainage at the center lug groove 41 while suppressing the rigidity of the center rib 11 from being partially lowered. In other words, when the maximum groove depth D2 of the widened portions 52 and 62 is (D2 / DC) <0.8 with respect to the groove depth DC of the circumferential main groove 20, the maximum groove of the widened portions 52 and 62 is obtained. The depth D2 may be too shallow. In this case, it becomes difficult to ensure drainage by the center lug groove 41, and it may be difficult to ensure wet performance. When the maximum groove depth D2 of the widened portions 52 and 62 is (D2 / DC)> 1.0 with respect to the groove depth DC of the circumferential main groove 20, the maximum groove of the widened portions 52 and 62 is obtained. The depth D2 may be too deep. In this case, the rigidity of the center rib 11 in the vicinity of the widened portions 52 and 62 becomes too low, and there is a risk that uneven wear tends to occur.

  On the other hand, the maximum groove depth D2 of the widened portions 52 and 62 of the center lug groove 41 is in a range of 0.8 ≦ (D2 / DC) ≦ 1.0 with respect to the groove depth DC of the circumferential main groove 20. If it is inside, it is possible to ensure drainage performance in the center lug groove 41 while suppressing the rigidity of the center rib 11 from being partially lowered. As a result, the occurrence of uneven wear can be suppressed while ensuring the wet performance more reliably.

  Moreover, the relationship between the distance LC in the tire circumferential direction between the center lug grooves 41 adjacent to each other in the tire circumferential direction and the width W6 in the tire circumferential direction of the constant width portions 51 and 61 of the center lug groove 41 is 0.05 ≦ ( (W6 / LC) ≦ 0.15, so that the drainage at the center lug groove 41 is ensured while reducing the sound when the center lug groove 41 in the center rib 11 is formed near the ground. be able to. That is, when the relationship between the distance LC between the center lug grooves 41 and the width W6 of the constant width portions 51 and 61 is (W6 / LC) <0.05, the width W6 of the constant width portions 51 and 61 is small. Or the distance LC between the center lug grooves 41 may be too large. In these cases, it is difficult to ensure drainage by the center lug groove 41, and it may be difficult to ensure wet performance. Further, when the relationship between the distance LC between the center lug grooves 41 and the width W6 of the constant width portions 51 and 61 is (W6 / LC)> 0.15, the width W6 of the constant width portions 51 and 61 is large. Or the distance LC between the center lug grooves 41 may be too small. In these cases, the hitting sound at the time of ground contact at the position where the center lug groove 41 is formed in the center rib 11 may be increased, and it may be difficult to reduce the noise.

  On the other hand, when the relationship between the distance LC between the center lug grooves 41 and the width W6 of the constant width portions 51 and 61 is within the range of 0.05 ≦ (W6 / LC) ≦ 0.15, the center lug The water drainage at the center lug groove 41 can be ensured while suppressing the hitting sound at the time of ground contact at the position where the groove 41 is formed. As a result, it is possible to reduce noise while ensuring wet performance more reliably.

  Further, of the two rows of center ribs 11 adjacent to each other via the center circumferential main groove 21, the second center lug groove 60 and the first notch 91 arranged in one center rib 11 and adjacent in the tire circumferential direction. And a distance L4 in the tire circumferential direction and a second center lug groove 60 that is disposed on the other center rib 11 and that has a position in the tire circumferential direction that defines the distance L4 and a first notch 91. 2 The relationship between the center lug groove 60 or the first notch 91 and the shorter distance L5 of the second center lug groove 60 and the first notch 91 defining the distance L4 is 0.4 ≦ (L5 / L4) Since it is within the range of 0.5, it is possible to more reliably reduce the hitting sound at the time of contact at the position where the second center lug groove 60 and the first notch 91 are formed. That is, when the relationship between the distance L4 and the distance L5 is (L5 / L4) <0.4, the second center lug grooves 60 provided in the center rib 11 or the first notches 91 or the first The distance in the tire circumferential direction between the two center lug grooves 60 and the first notch 91 may be too small. In this case, the hitting sound at the time of contact with the center rib 11 at the position where the second center lug groove 60 and the first notch 91 are formed is continuously generated, and the hitting sound is likely to increase. It may be difficult to achieve.

  On the other hand, when the relationship between the distance L4 and the distance L5 is within the range of 0.4 ≦ (L5 / L4) ≦ 0.5, the second center lug grooves 60 are adjacent to each other between the adjacent center ribs 11. , The distance between the first notches 91, and the distance between the second center lug groove 60 and the first notch 91 can be set to an appropriate size and separated from each other by an appropriate size. The hitting sound at the time of ground contact at the position where the lug groove 60 and the first notch 91 are formed can be more reliably suppressed. As a result, noise reduction can be achieved more reliably.

  Further, the distance L4 in the tire circumferential direction between the first center lug groove 50 and the second notch 95 adjacent in the tire circumferential direction and the position in the tire circumferential direction among the plurality of shoulder lug grooves 42 define the distance L4. Relationship between the shorter distance L6 of the first center lug groove 50 and the second notch 95 defining the distance L4 and the shoulder lug groove 42 located between the first center lug groove 50 and the second notch 95 Is within the range of 0.4 ≦ (L6 / L4) ≦ 0.5, so that the shoulder lug at the position where the first center lug groove 50 and the second notch 95 are formed or at the shoulder block 12 The hitting sound at the time of ground contact in the vicinity of the groove 42 can be more reliably reduced. That is, when the relationship between the distance L4 and the distance L6 is (L6 / L4) <0.4, the distance between the first center lug groove 50 and the shoulder lug groove 42 in the tire circumferential direction, or the second notch There is a possibility that the distance between the tire 95 and the shoulder lug groove 42 in the tire circumferential direction becomes too small. In this case, a hitting sound is continuously generated when the center rib 11 contacts the position where the first center lug groove 50 and the second notch 95 are formed or when the shoulder block 12 contacts the shoulder lug groove 42. Since the hitting sound is likely to increase, it may be difficult to reduce the noise.

  On the other hand, when the relationship between the distance L4 and the distance L6 is within the range of 0.4 ≦ (L6 / L4) ≦ 0.5, the tire circumference between the first center lug groove 50 and the shoulder lug groove 42 is Since the distance in the tire direction and the distance between the second notch 95 and the shoulder lug groove 42 in the tire circumferential direction can be set to an appropriate size and separated from each other by an appropriate size, the first center lug groove 50 and the second The hitting sound at the time of ground contact at the position where the two notches 95 are formed or at the time of ground contact in the vicinity of the shoulder lug groove 42 in the shoulder block 12 can be more reliably suppressed. As a result, noise reduction can be achieved more reliably.

[Modification]
In the pneumatic tire 1 according to the above-described embodiment, only the circumferential main groove 20 and the lug groove 40 are provided on the tread surface 3, but the circumferential main groove 20 and the lug are provided on the tread surface 3. Other than the groove 40 may be provided. FIG. 15 is a modified example of the pneumatic tire 1 according to the embodiment, and is an explanatory diagram when a sipe is formed on the tread surface 3. A plurality of sipes may be formed on the tread surface 3. As the sipe, for example, as shown in FIG. 15, a bent sipe 101 may be provided on the center rib 11, a lug groove sipe 102 may be provided, or a rib edge sipe 103 may be provided on the shoulder block 12. Among these, the bent sipe 101 is a so-called closed sipe 100 whose both ends terminate in the center rib 11, and the first center lug groove 50 and the second center adjacent to each other in the tire circumferential direction are located in the tire circumferential direction. It is located between the lug grooves 60. The bending sipe 101 is formed in a crank shape by being bent at two locations while extending in the tire width direction.

  Similarly to the bent sipe 101, the lug groove sipe 102 is a closed sipe 100 that ends in the center rib 11, and the position in the tire circumferential direction is the position of the first center lug groove 50 in the tire circumferential direction. The second center lug groove 60 is disposed at the same position as the position in the tire circumferential direction. Specifically, the lug groove sipe 102 is disposed along the extending direction of the first center lug groove 50 and the second center lug groove 60, and a part thereof is the first center lug groove 50 and the second center lug groove. It overlaps with 60. That is, part of the lug groove sipe 102 is formed at the groove bottom of the first center lug groove 50 or the second center lug groove 60.

  The rib edge sipe 103 is formed at the edge of the shoulder block 12 that is defined by the shoulder circumferential main groove 22. The rib edge sipe 103 extends in the tire width direction with a short length and opens at one end in the shoulder circumferential main groove 22. The other end is a sipe that terminates in the shoulder block 12. In the example shown in FIG. 15, two rib edge sipes 103 are disposed between the first shoulder lug groove 70 and the second shoulder lug groove 80 adjacent to each other in the tire circumferential direction.

  The sipe here is formed in a narrow groove shape on the tread surface 3, and the pneumatic tire 1 is assembled with a rim on a normal rim, and a narrow groove is formed when there is no load under normal internal pressure conditions. Although the wall surfaces do not contact each other, when the narrow groove is located in the portion of the ground contact surface formed on the flat plate when loaded in the vertical direction on the flat plate, or when the land portion 10 where the narrow groove is formed falls, The wall surface which comprises the said narrow groove, or at least one part of the site | part provided in a wall surface says what mutually contacts by the deformation | transformation of the land part 10. FIG.

  The regular rim is “standard rim” defined by JATMA, “Design Rim” defined by TRA, or “Measuring Rim” defined by ETRTO. The normal internal pressure is “maximum air pressure” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO.

  By arranging the sipe such as the bent sipe 101, the lug groove sipe 102, and the rib edge sipe 103 on the tread surface 3, the edge component can be increased, and the traction performance during traveling on a wet road surface is ensured. be able to. Further, since the sipe is closed when the tread surface 3 on which the sipe is formed is grounded, it is possible to suppress the sound generated when the tread surface 3 is grounded from flowing through the sipe to the outside in the tire width direction. In particular, since the bent sipe 101 and the lug groove sipe 102 which are the closed sipe 100 are not in communication with the circumferential main groove 20, the bent sipe 101, the lug groove sipe 102, and the circumferential main groove 20 are not connected. Therefore, the sound generated when the tread surface 3 is grounded can be prevented from flowing between the different regions through the bending sipe 101 and the lug groove sipe 102. As a result, the noise can be reduced more reliably while ensuring the wet performance.

  FIG. 16 is a detailed view of the bent sipe 101 shown in FIG. The bending sipe 101 has a width W7 in the tire width direction within a range of 0.6 ≦ (W7 / W1) ≦ 0.9 with respect to the width W1 in the tire width direction of the center rib 11 on which the bending sipe 101 is formed. It has become. Thereby, it is possible to increase the edge component more reliably while suppressing the occurrence of cracks at the end position of the bent sipe 101. That is, when the width W7 of the bent sipe 101 is (W7 / W1) <0.6 with respect to the width W1 of the center rib 11 in the tire width direction, the width W7 of the bent sipe 101 is too small. Even if the sipe 101 is provided, the edge component may not be effectively increased. In this case, it may be difficult to improve the traction performance when traveling on a wet road surface. When the width W7 of the bent sipe 101 is (W7 / W1)> 0.9 with respect to the width W1 of the center rib 11 in the tire width direction, the width W7 of the bent sipe 101 is too large. In the rib 11, the thickness between the end of the bent sipe 101 and the circumferential main groove 20 becomes too thin, and there is a risk of cracks.

  On the other hand, when the width W7 of the bending sipe 101 is in the range of 0.6 ≦ (W7 / W1) ≦ 0.9 with respect to the width W1 of the center rib 11 in the tire width direction, the bending sipe 101 The edge component can be increased more reliably by the bent sipe 101 while suppressing the occurrence of cracks at the position of the end of the sipe. As a result, noise reduction can be achieved while ensuring wet performance more reliably without generating sipe cracks.

  17 is a cross-sectional view taken along the line KK of FIG. The bent sipe 101 has a shallow bottom portion 105 that is shallower than the depths at both ends of the bent sipe 101. That is, the bent sipe 101 has a shallow bottom portion at a position near the center in the extending direction of the bent sipe 101 by raising the bottom at a position near the center in the extending direction of the bent sipe 101 or the tire width direction. 105 is formed. Since the bent sipe 101 is formed with the shallow bottom portion 105, the bent sipe 101 is not easily opened and closed when the pneumatic tire 1 rolls. As a result, it is possible to suppress the occurrence of cracks at the bottom of the bent sipe 101, which are caused by repeated opening and closing of the bent sipe 101.

  Further, in the bent sipe 101, the relationship between the minimum depth D3 at the position of the shallow bottom portion 105 and the maximum depth D4 of the bent sipe 101 is within a range of 0.4 ≦ (D3 / D4) ≦ 0.6. It has become. Thereby, wet performance can be improved more reliably while suppressing sipe cracks. That is, if the relationship between the minimum depth D3 at the position of the shallow bottom portion 105 and the maximum depth D4 of the bending sipe 101 is (D3 / D4) <0.4, the minimum depth D3 may be too shallow. There is a possibility that the bent sipe 101 is easily maintained in a closed state. In this case, when traveling on a wet road surface, it becomes difficult for water to enter the bent sipe 101 and it becomes difficult to exhibit the effect of improving the traction performance by the edge component, which may make it difficult to improve the wet performance. In addition, when the relationship between the minimum depth D3 at the position of the shallow bottom portion 105 and the maximum depth D4 of the bending sipe 101 is (D3 / D4)> 0.6, the minimum depth D3 may be too deep. Therefore, it is difficult to reduce the opening and closing of the bent sipe 101 accompanying the rolling of the pneumatic tire 1, and it may be difficult to suppress the occurrence of cracks.

  On the other hand, when the relationship between the minimum depth D3 at the position of the shallow bottom portion 105 and the maximum depth D4 of the bending sipe 101 is within a range of 0.4 ≦ (D3 / D4) ≦ 0.6. The wet sipe 101 can improve the wet performance more reliably while suppressing the occurrence of cracks in the bent sipe 101. As a result, noise reduction can be achieved while ensuring wet performance more reliably without generating sipe cracks.

  18 is a detailed view of the lug sipe 102 shown in FIG. The lug groove sipe 102 is disposed so as to partially overlap the center lug groove 41, extends along the extending direction of the center lug groove 41, and is opposite to the end on the side overlapping the center lug groove 41. Is located in the vicinity of the notch 90 located on the extension line of the center lug groove 41. In the lug groove sipe 102 formed in this way, the relationship between the width W8 in the tire width direction and the distance W9 between the widened portions 52 and 62 of the center lug groove 41 and the notch 90 in the tire width direction is 0. It is in the range of 6 ≦ (W8 / W9) ≦ 0.9. Thereby, it is possible to increase the edge component more reliably while suppressing the occurrence of cracks at the end position of the lug groove sipe 102.

  That is, when the relationship between the distance W9 between the widened portions 52 and 62 of the center lug groove 41 and the notch 90 and the width W8 of the lug groove sipe 102 is (W8 / W9) <0.6, the lug groove Since the width W8 of the sipe 102 is too small, it is difficult to effectively increase the edge component even if the lug groove sipe 102 is provided. In this case, it may be difficult to improve the traction performance when traveling on a wet road surface. When the relationship between the distance W9 between the widened portions 52 and 62 of the center lug groove 41 and the notch 90 and the width W8 of the lug groove sipe 102 is (W8 / W9)> 0.9, the lug groove Since the width W8 of the sipe 102 is too large, the thickness of the center rib 11 between the end portion of the lug groove sipe 102 and the widened portions 52 and 62, or between the end portion of the lug groove sipe 102 and the notch 90 is increased. There is a risk that the wall thickness of the film becomes too thin and cracks occur.

  On the other hand, the relationship between the distance W9 between the widened portions 52 and 62 of the center lug groove 41 and the notch 90 and the width W8 of the lug groove sipe 102 is 0.6 ≦ (W8 / W9) ≦ 0.9. When it is within the range, the edge component can be more reliably increased by the lug groove sipe 102 while suppressing the occurrence of cracks at the end portion of the lug groove sipe 102. As a result, noise reduction can be achieved while ensuring wet performance more reliably without generating sipe cracks.

  19 is a cross-sectional view taken along line MM in FIG. Similarly to the bent sipe 101, the lug groove sipe 102 also has a shallow bottom portion 105 that is shallower than the depths at both ends of the lug groove sipe 102. Unlike the bent sipe 101, the lug groove sipe 102 has two shallow bottom portions 105. In other words, the lug groove sipe 102 is raised at the two positions separated in the extending direction of the lug groove sipe 102 or in the tire width direction, and the two bottom portions are raised in the extending direction of the lug groove sipe 102. A shallow bottom portion 105 is formed at the position. When the pneumatic tire 1 rolls, the lug groove sipe 102 is not easily opened and closed because the shallow bottom portion 105 is formed. As a result, it is possible to suppress the occurrence of cracks at the bottom of the lug groove sipe 102 that are generated due to repeated opening and closing of the lug groove sipes 102. In the lug groove sipe 102, the relationship between the minimum depth D3 at the position of the shallow bottom portion 105 and the maximum depth D4 of the lug groove sipe 102 is in a range of 0.4 ≦ (D3 / D4) ≦ 0.6. Therefore, similarly to the bent sipe 101, noise can be reduced while ensuring wet performance more reliably without generating sipe cracks.

  The maximum depth D4 of the bent sipe 101 and the maximum depth D4 of the lug groove sipe 102 are 0.5 ≦ (D4 / DC) ≦ 0 with respect to the groove depth DC of the circumferential main groove 20. Is preferably within the range of .8. The maximum depth D4 of the lug groove sipe 102 is in the range of 0.2 ≦ (D1 / D4) ≦ 0.5 in relation to the minimum groove depth D1 of the constant width portions 51 and 61 of the center lug groove 41. Is preferably within.

  In the above-described embodiment, the center lug grooves 41 and the notches 90 are all formed in the same shape, but may not be formed in the same shape. For example, the first center lug groove 50 and the second center lug groove 60 may have different shapes, and the first notch 91 and the second notch 95 may have different shapes.

  In the above-described embodiment, three circumferential main grooves 20 are provided, but the number of circumferential main grooves 20 may be other than three. A plurality of circumferential main grooves 20 may be provided, and at least one land portion 10 among the plurality of land portions 10 has one end opened to the circumferential main groove 20 and the other end within the land portion 10. The lug groove 40 that terminates and a plurality of notches 90 that are located on the extension line of the end portion of the lug groove 40 that terminates in the land portion 10 and that open to the circumferential main groove 20 are provided. The number of the circumferential main grooves 20 is not limited as long as the grooves 40 and the notches 90 are arranged in a staggered arrangement.

〔Example〕
20A to 20E are tables showing results of performance tests of pneumatic tires. Hereinafter, the performance evaluation test performed on the pneumatic tire 1 of the conventional example and the pneumatic tire 1 according to the present invention will be described. In the performance evaluation test, a test was conducted on wet traction, which is traction performance on a wet road surface, and passing noise, which is performance on noise generated with the rolling of the pneumatic tire 1.

  In the performance evaluation test, a pneumatic tire 1 with a tire size specified by JATMA of 205 / 85R16 size is assembled to a regular rim, the air pressure is adjusted to a regular internal pressure, and a 2-D test vehicle (tractor head) The test was carried out by wearing it. The evaluation method of each test item is evaluated by measuring the acceleration of a speed section of 5 to 20 km / h on a wet road surface and expressing the average acceleration with an index with a conventional example of 100 described later as the wet traction property. did. It shows that wet traction property is excellent, so that a numerical value is large.

  The passing noise was evaluated based on the magnitude of the passing sound measured outside the vehicle according to the tire noise test method defined in ECE R117-02 (ECE Regulation No. 117 Revision 2). In this test, the maximum noise value dB (frequency in a frequency range of 800 Hz to 1200 Hz) in the noise measurement section when the test vehicle is run sufficiently before the noise measurement section, the engine is stopped before the section, and the coasting is made. Value) was measured at a plurality of speeds in which a speed range of ± 10 km / h with respect to the reference speed was divided into eight or more at almost equal intervals, and the average was defined as vehicle outside noise. The maximum noise value dB was measured through an A characteristic frequency correction circuit using a stationary microphone installed at a height of 7.5 m to the side of the running center line and 1.2 m from the road surface at an intermediate point in the noise measurement section. Sound pressure dB (A). For the passing noise, this measurement result was expressed as a difference in sound pressure dB with respect to the passing noise of the conventional example with reference to the passing noise of the conventional example described later. The smaller the sound pressure dB with respect to the passing noise of the conventional example, the better the performance with respect to the passing noise.

  The evaluation test was performed on 40 types of pneumatic tires, a conventional pneumatic tire which is an example of the conventional pneumatic tire 1 and Examples 1 to 39 which are the pneumatic tire 1 according to the present invention. Among these pneumatic tires 1, in the conventional pneumatic tire, all the lug grooves are open on both sides of the land portion, and no notch is provided on the extended line of the lug grooves.

  On the other hand, Examples 1-39 which are examples of the pneumatic tire 1 which concerns on this invention have the center lug groove 41 which is all the one side opening lug grooves, and it cuts on the extension line of the center lug groove 41. A notch 90 is provided, and the center lug groove 41 and the notch 90 are arranged in a staggered manner. Further, in the pneumatic tire 1 according to Examples 1 to 39, the ratio (L1 / W1) of the length L1 of the center lug groove 41 to the width W1 of the center rib 11 and the notch 90 with respect to the width W1 of the center rib 11 The ratio of the length L2 (L2 / W1), the ratio of the minimum width W2 to the maximum width W3 of the notch 90 (W2 / W3), the groove width W5 of the center lug groove 41 at the opening positions of the widened portions 52 and 62 The ratio (W4 / W5) of the groove width W4 of the constant width portions 51, 61, the ratio (L3 / L1) of the length L3 of the constant width portions 51, 61 to the length L1 of the center lug groove 41, The ratio (D1 / D2) of the minimum groove depth D1 of the constant width portion 51 to the maximum groove depth D2 of the widened portion 52, and the ratio of the width W6 of the constant width portion 61 to the distance LC between the adjacent center lug grooves 41 ( W6 / LC), closed The adjacent land portion 10 with respect to the distance L4 between the center lug groove 41 and the notch 90 adjacent to each other in the tire circumferential direction (D3 / D4), the ratio of the shallow bottom portion 105 to the maximum depth D4 of the closed sipe 100 The ratio (L5 / L4) of the distance L5 between the center lug groove 41 or notch 90 provided in the center lug 41 and the center lug groove 41 or notch 90 defining the distance L4, and the center lug groove 41 and the notch adjacent to each other in the tire circumferential direction. The ratio (L6 / L4) of the distance L6 between the center lug groove 41 or the notch 90 and the shoulder lug groove 42 defining the distance L4 with respect to the distance L4 with the notch 90 is different.

  As a result of conducting an evaluation test using these pneumatic tires 1, as shown in FIGS. 20A to 20E, the pneumatic tires 1 of Examples 1 to 39 have lower wet traction than the conventional examples. Without passing through, it was found that the passing noise was reduced. That is, the pneumatic tire 1 according to Examples 1 to 39 can achieve low noise while ensuring wet performance.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 3 Tread surface 4 Shoulder part 5 Side wall part 6 Carcass 7 Belt layer 8 Inner liner 10 Land part 11 Center rib 12 Shoulder block (shoulder land part)
13 shoulder block row 20 circumferential main groove 21 center circumferential main groove 22 shoulder circumferential main groove 30 bead portion 40 lug groove 41 center lug groove (one side open lug groove)
42 shoulder lug groove 50 first center lug groove 51, 61 constant width part 52, 62 widened part 53, 63 opening part 54, 64 end 60 second center lug groove 70 first shoulder lug groove 71, 81 constant width part 72 , 82 Widened portion 73, 83 Bent portion 74, 84 Inner opening 75, 85 Outer opening 80 Second shoulder lug groove 90 Notch 91 First notch 92, 96 End portion 95 Second notch 100 Closed sipe 101 Bending Sipe 102 Rug groove sipe 103 Rib edge sipe 105 Shallow bottom

Claims (13)

A plurality of circumferential main grooves formed on the tread surface and extending in the tire circumferential direction;
A plurality of lug grooves formed on the tread surface and extending in the tire width direction;
A plurality of land portions in which at least one end portion in the tire width direction is partitioned by the circumferential main groove;
With
At least one of the plurality of land portions includes a one-sided opening lug groove that is the lug groove having one end opening in the circumferential main groove and the other end terminating in the land portion, and the one-side opening. A plurality of notches that are located on the extension line of the end portion on the side terminating in the land portion in the lug groove and that open to the circumferential main groove are provided, respectively.
The one side opening lug groove and the notch are arranged in a staggered arrangement by alternately arranging the one side opening lug groove and the notch in the tire circumferential direction. Pneumatic tire.   The one-side opening lug groove has a length L1 in the tire width direction of the one-side opening lug groove of the land portion in which the one-side opening lug groove is disposed is 0.3 ≦. The pneumatic tire according to claim 1, which is in a range of (L1 / W1) ≦ 0.6.   In the notch, the length L2 of the notch in the tire width direction is 0.05 ≦ (L2 / W1) ≦ with respect to the width W1 in the tire width direction of the land portion where the notch is disposed. The pneumatic tire according to claim 1 or 2, which is within a range of 0.20.   The notch has a larger width in the tire circumferential direction as it approaches the circumferential main groove from a position away from the circumferential main groove in which the notch opens in the tire width direction. The pneumatic tire according to any one of claims 1 to 3, wherein a relationship between the minimum width W2 and the maximum width W3 is within a range of 0.4 ≦ (W2 / W3) ≦ 0.6. The one-side opening lug groove has a constant width portion formed with a constant groove width and a widened portion where the groove width changes, and the widened portion is open to the circumferential main groove,
The constant width portion extends from the side opposite to the side opening in the circumferential main groove in the widened portion to the end portion on the side terminating in the land portion in the one side opening lug groove,
The widened portion has a groove width that increases from the constant width portion side toward the side opened to the circumferential main groove,
The relationship between the groove width W5 at the opening in the circumferential main groove in the widened portion and the groove width W4 of the constant width portion is in a range of 0.4 ≦ (W4 / W5) ≦ 0.6. It is inside. The pneumatic tire of any one of Claims 1-4.   The one-side opening lug groove has a length L3 in the tire width direction of the constant width portion with respect to a length L1 of the one-side opening lug groove in the tire width direction of 0.6 ≦ (L3 / L1) ≦ 0. The pneumatic tire according to claim 5, which is within a range of 8. The groove depth of the widened portion is deeper than the groove depth of the constant width portion,
The minimum groove depth D1 of the constant width portion is within a range of 0.2 ≦ (D1 / D2) ≦ 0.5 with respect to the maximum groove depth D2 of the widened portion. Pneumatic tires.   The maximum groove depth D2 of the widened portion is in a range of 0.8 ≦ (D2 / DC) ≦ 1.0 with respect to the groove depth DC of the circumferential main groove in which the widened portion opens. The pneumatic tire according to any one of Items 5 to 7. LC is the distance in the tire circumferential direction between the one side opening lug grooves that are opened in the same circumferential main groove and adjacent in the tire circumferential direction,
When the width in the tire circumferential direction of the constant width portion is W6,
The pneumatic tire according to any one of claims 5 to 8, wherein a relationship between the distance LC and the width W6 is in a range of 0.05 ≦ (W6 / LC) ≦ 0.15.   The land portion where the one side opening lug groove and the notch are disposed is not formed with grooves and sipes that are open at both ends in the circumferential main groove, and both ends are terminated within the land portion. The pneumatic tire according to any one of claims 1 to 9, wherein a sipe is provided. The closed sipe has a shallow bottom portion that is shallower than the depths at both ends of the closed sipe;
The relationship between the minimum depth D3 at the position of the shallow bottom and the maximum depth D4 of the closed sipe is within a range of 0.4 ≦ (D3 / D4) ≦ 0.6. Pneumatic tire. At least three of the circumferential main grooves are provided side by side in the tire width direction,
The land portion where the one-side opening lug groove and the notch are disposed is disposed so that at least two rows are adjacent to each other in the tire width direction via the circumferential main groove,
The one-side opening lug groove and the notch are disposed and are disposed in one of the land portions of the two adjacent land portions via the circumferential main groove and are adjacent in the tire circumferential direction. The distance in the tire circumferential direction between the one side opening lug groove and the notch is L4,
The one side opening lug groove which is disposed in the other land portion and defines the distance L4 and the same circumferential main groove as the notch are opened, and the position in the tire circumferential direction defines the distance L4 Of the distances in the tire circumferential direction between the one side opening lug groove or the notch located between the one side opening lug groove and the notch, and the one side opening lug groove and the notch defining a distance L4 When the shorter distance is L5,
The pneumatic tire according to any one of claims 1 to 11, wherein a relationship between the distance L4 and the distance L5 is within a range of 0.4 ≦ (L5 / L4) ≦ 0.5. Three circumferential main grooves are provided side by side in the tire width direction,
The land portion is provided with four rows arranged in the tire width direction,
The one-side opening lug groove and the notch are positioned on the outer side in the tire width direction of the shoulder circumferential main groove, which is the circumferential main groove located on the outermost side in the tire width direction among the three circumferential main grooves. It is arranged in a staggered arrangement in the land portion other than the shoulder land portion, which is the land portion,
In the shoulder land portion, a plurality of shoulder lug grooves which are the lug grooves opening from the outer side in the tire width direction with respect to the shoulder circumferential main groove are formed,
L4 is a distance in the tire circumferential direction between the one-side opening lug groove adjacent to the shoulder circumferential direction and the notch disposed in the land portion adjacent to the shoulder land portion via the shoulder circumferential main groove,
Among the plurality of shoulder lug grooves, a position in the tire circumferential direction defines the distance L4, the shoulder lug groove located between the one-side opening lug groove and the notch, and the one-side opening lug groove defining the distance L4 When the shorter distance among the distances between the notches and the notches in the tire circumferential direction is L6,
The pneumatic tire according to any one of claims 1 to 12, wherein a relationship between the distance L4 and the distance L6 is within a range of 0.4 ≦ (L6 / L4) ≦ 0.5.

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