JP6790443B2 - Pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire.

Pneumatic tires have grooves on the tread surface to ensure running performance in rainy weather, and the water between the tread surface and the road surface is drained by the grooves, while the grooves on the tread surface are unevenly worn. It also causes. In particular, since a large load acts on the shoulder region when turning, uneven wear is likely to occur. Therefore, some conventional pneumatic tires are designed to suppress uneven wear in the shoulder region. is there. For example, the pneumatic tire described in Patent Document 1 has a lug groove and a sipe extending from the main groove side toward the shoulder end side and a lug groove extending from the shoulder end side toward the main groove side in the tire circumferential direction. By arranging them alternately and making the land part continuous in a zigzag shape with respect to the tire circumferential direction, it is possible to suppress the concentration of load when the pneumatic tire rotates, and to suppress uneven wear.

Japanese Patent No. 5249666

However, in the shoulder region, when the lug grooves and sipe extending from the main groove side to the shoulder end side and those extending from the shoulder end side to the main groove side are alternately arranged in the tire circumferential direction, the grooves are arranged with each other. There is a risk that the rigidity of the land area will decrease due to the narrowing of the intervals between the tires. The rigidity of the land part is an important factor for steering stability, and if the rigidity of the land part is lowered, the maneuverability may be lowered. Therefore, it has been very difficult to suppress uneven wear without lowering the maneuverability.

The present invention has been made in view of the above, and an object of the present invention is to provide a pneumatic tire capable of achieving both maneuverability and uneven wear resistance.

In order to solve the above-mentioned problems and achieve the object, the pneumatic tire according to the present invention is formed on the tread surface and has a plurality of main grooves extending in the tire circumferential direction and a plurality of main grooves in the tire width direction. Located on the outermost side of the outermost main groove, which is the outermost main groove, adjacent to the outermost main groove in the tire width direction, and a shoulder land portion through which the ground contact end passes, and one end extending in the tire width direction. A plurality of inner shoulder lug grooves connected to the outermost main groove and the other end ending in the shoulder land portion and the adjacent inner shoulder lug grooves are arranged between the adjacent inner shoulder lug grooves and extend in the tire width direction, and at least the tire. The outer end in the width direction extends in the tire width direction across the plurality of inner shoulder grooves and the ground contact end, and at least the inner end in the tire width direction ends in the shoulder land portion. It is arranged between a plurality of outer shoulder lug grooves and adjacent outer shoulder lug grooves and extends in the tire width direction across the ground contact end, and at least the inner end in the tire width direction is within the shoulder land portion. A plurality of outer shoulder grooves to be terminated, and an inner shoulder lug groove end portion which is an outer end portion of the inner shoulder lug groove in the tire width direction and an inner portion which is an outer end portion of the inner shoulder lug groove in the tire width direction. The shoulder narrow groove end is a combination of the outer shoulder lug groove end which is the inner end of the outer shoulder lug groove in the tire width direction and the outer shoulder narrow groove end which is the inner end of the outer shoulder lug groove in the tire width direction. Is also located inside in the tire width direction, and the shoulder land portion is located between the inner shoulder lug groove and the inner shoulder groove in the tire width direction and the outer shoulder lug groove and the outer shoulder groove. It has a plane region that is a region where no groove is formed over the entire circumference in the tire circumferential direction, and the distance between the outermost main groove and the ground contact end in the tire width direction is the ground contact width of the shoulder land portion. In the case of W1, the plane region is characterized in that the width W2 in the tire width direction is within a range of 20% or more and 80% or less with respect to the ground contact width W1.

Further, in the pneumatic tire, the plane region is located at a position where the distance WL in the tire width direction from the outermost main groove is within a range of 20% or more and 40% or less with respect to the ground contact width W1. Is preferable.

Further, in the pneumatic tire, the distance L1 between the outer shoulder lug groove ends of the outer shoulder lug grooves adjacent to each other in the tire circumferential direction and the position in the tire circumferential direction are located between the outer shoulder lug groove ends. The relationship between the inner shoulder lug groove end portion and the outer shoulder lug groove end portion of any one of the outer shoulder lug groove end portions and the distance L2 in the tire circumferential direction is 0.2 ≦ (L2 / L1). ) ≤ 0.8 is preferable.

Further, in the pneumatic tire, the relationship between the distance W3 in the tire width direction from the ground contact end to the outer shoulder narrow groove end portion and the distance W5 in the tire width direction from the ground contact end to the outer shoulder lug groove end portion. Is within the range of 0.2 ≦ (W3 / W5) ≦ 0.8, the length W4 of the inner shoulder narrow groove in the tire width direction, and the tire from the outermost main groove to the inner shoulder lug groove end. The relationship with the distance W6 in the width direction is preferably in the range of 0.2 ≦ (W4 / W6) ≦ 0.8.

Further, in the pneumatic tire, the outer side of the outer shoulder narrow groove end portion of the outer shoulder narrow groove and one of the two outer shoulder lug grooves adjacent to the outer shoulder narrow groove in the tire width direction. When the distance from the shoulder lug groove in the tire circumferential direction is L3 and the distance between the outer shoulder narrow groove end and the other outer shoulder lug groove in the tire circumferential direction is L4, the distance L3 and the distance L4 Is within the range of 0.8 ≦ (L3 / L4) ≦ 1.2, and the inner shoulder groove and the two inner shoulder lug grooves adjacent to the inner shoulder groove in the tire width direction. In the case where the inner shoulder narrow groove end portion of the inner shoulder narrow groove is located outside the inner shoulder lug groove end portion of the inner shoulder lug groove in the tire width direction, the two inner shoulder lug grooves The distance between the inner shoulder lug groove end portion of one of the inner shoulder lug grooves and the inner shoulder narrow groove in the tire circumferential direction is L5, and the inner shoulder lug groove end portion and the inner side of the other inner shoulder lug groove. Assuming that the distance from the shoulder narrow groove in the tire circumferential direction is L6, the distance L5 and the distance L6 are within the range of 0.8 ≦ (L5 / L6) ≦ 1.2, and the inner shoulder lug groove When the inner shoulder narrow groove end of the inner shoulder narrow groove is located inside in the tire width direction than the inner shoulder lug groove end, of the inner shoulder lug groove end and the two inner shoulder lug grooves. The distance between the inner shoulder lug groove and the inner shoulder lug groove in the tire circumferential direction is L5, and the distance between the inner shoulder narrow groove end and the other inner shoulder lug groove in the tire circumferential direction is L6. It is preferable that L6 is in the range of 0.8 ≦ (L5 / L6) ≦ 1.2.

Further, in the pneumatic tire, the area of a rectangle whose corners are the four ends of the two outer shoulder lug grooves adjacent to each other is S1, and the four sides forming the rectangle are defined as S1. Of these, two intersections of an extension line extending the two sides connecting the ends of one outer shoulder lug groove toward the outermost main groove and the outermost main groove, and two outer sides. When the area of the rectangle whose corners are the two outer shoulder lug groove ends of the shoulder lug groove is S2, the area S1 and the area S2 are 1 ≦ (S2 / S1) ≦ 1.3. It is preferable that the relationship is within the range of.

The pneumatic tire according to the present invention has an effect that both maneuverability and uneven wear resistance can be achieved at the same time.

FIG. 1 is a plan view showing a tread surface of a pneumatic tire according to an embodiment. FIG. 2 is a detailed view of part A of FIG. FIG. 3 is an explanatory view of the relative positional relationship between the lengths of the lug groove and the narrow groove in the land portion of the shoulder. FIG. 4 is an explanatory view of a region in the land portion of the shoulder where the outer shoulder lug groove is not provided. FIG. 5 is a modified example of the pneumatic tire according to the embodiment, and is an explanatory view when the inner shoulder narrow groove end portion is located outside the inner shoulder lug groove end portion in the tire width direction. FIG. 6 is a modification of the pneumatic tire according to the embodiment, and is an explanatory view when the inner shoulder narrow groove end portion is located outside the inner shoulder lug groove end portion in the tire width direction. FIG. 7A is a chart showing the results of performance tests of pneumatic tires. FIG. 7B is a chart showing the results of performance tests of pneumatic tires.

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

In the following description, the tire width direction means a direction parallel to the rotation axis of the pneumatic tire, the inside in the tire width direction is the direction toward the tire equatorial plane in the tire width direction, and the outside in the tire width direction is 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, and the tire circumferential direction means a direction of rotation about the tire rotation axis.

FIG. 1 is a plan view showing a tread surface of a pneumatic tire according to an embodiment. In the pneumatic tire 1 shown in FIG. 1, the tread portion 2 is arranged on the outermost portion in the tire radial direction, and the surface of the tread portion 2, that is, the vehicle on which the pneumatic tire 1 is mounted ( The portion that comes into contact with the road surface during traveling (not shown) is formed as a tread surface 3. A plurality of grooves 5 are formed on the tread surface 3, and a plurality of land portions 40 are partitioned by the plurality of grooves 5. The grooves 5 include a main groove 10 extending in the tire circumferential direction, a lug groove 20 extending in the tire width direction, and a narrow groove 30 formed in which the groove width is narrower than that of the main groove 10 and the lug groove 20. , Each is formed in plurality.

In the present embodiment, three main grooves 10 are formed side by side at intervals in the tire width direction. That is, one main groove 10 is formed on the tire equatorial plane CL, and one main groove 10 is formed on both sides in the tire width direction with the tire equatorial plane CL interposed therebetween. The main groove 10 has a groove width within a range of 3 mm or more and 15 mm or less, and a groove depth within a range of 4 mm or more and 10 mm or less.

Of the three main grooves 10, the main groove 10 located on the tire equatorial plane CL is provided as the center main groove 11, is located outside the center main groove 11 in the tire width direction, and is located in the center main groove 11. On the other hand, the two adjacent main grooves 10 are provided as the outermost main grooves 15. That is, of the plurality of main grooves 10, the two main grooves 10 located on the outermost side in the tire width direction are provided as the outermost main grooves 15. Of the three main grooves 10, the center main groove 11 extends in the tire circumferential direction and oscillates in the tire width direction, that is, the center main groove 11 extends in the tire circumferential direction and has irregularities in the tire width direction. It is formed in a zigzag shape that repeats. Further, of the three main grooves 10, two outermost main grooves 15 are formed as straight grooves extending linearly in the tire circumferential direction.

The land portion 40 is divided into two center land portions 41 and two shoulder land portions 45 by three main grooves 10. Of these, the center land portion 41 is a land portion 40 partitioned by a center main groove 11 and an outermost main groove 15, and is located on both sides of the center main groove 11 in the tire width direction. It is formed between the center main groove 11 and the outermost main groove 15 on both sides in the tire width direction of the tire. Further, the shoulder land portion 45 is located outside the outermost main groove 15 in the tire width direction, is adjacent to the outermost main groove 15, and is a land portion 40 through which the ground contact end T passes. That is, the shoulder land portion 45 is a land portion 40 whose inner side in the tire width direction is partitioned by the outermost main groove 15, is located outside the outermost main groove 15 in the tire width direction, and is located outside the outermost main groove 15. It is formed from the tread surface 3 to the outer end in the tire width direction.

In this case, the ground contact end T is formed in the vertical direction on the flat plate under the specified internal pressure, for example, the internal pressure condition of the air pressure corresponding to the specified load and the specified load condition by mounting the pneumatic tire 1 on the specified rim. It refers to the position on the tread surface 3 corresponding to the outermost portion in the tire width direction on the ground contact surface formed on the flat plate when a load is applied. That is, the grounding end T is at the maximum position of the grounding width on the grounding surface at the specified internal pressure and the specified load.

The specified rim means an "applicable rim" specified in JATTA, a "Design Rim" specified in TRA, or a "Measuring Rim" specified in ETRTO. The specified internal pressure means the "maximum air pressure" specified in JATTA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified in TRA, or "INFLATION PRESSURES" specified in ETRTO. The specified load means the "maximum load capacity" specified in JATTA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified in TRA, or the "LOAD CAPACITY" specified in ETRTO.

The lug groove 20 is connected to the center lug groove 21 located between the center main groove 11 and the outermost main groove 15 and the outermost main groove 15 located outside the outermost main groove 15 in the tire width direction. It has an inner shoulder lug groove 23 and an outer shoulder lug groove 26 located outside the inner shoulder lug groove 23 in the tire width direction.

Of these, the outer end of the center lug groove 21 in the tire width direction is connected to the outermost main groove 15, and the inner end in the tire width direction is terminated in the center land portion 41. Further, the center lug groove 21 is curved in the tire circumferential direction while facing the tire width direction from the end side connected to the outermost main groove 15 toward the end side in the center land portion 41. ing. A plurality of center lug grooves 21 are formed so as to be arranged side by side in the tire circumferential direction at positions between the two center main grooves 11 and the outermost main grooves 15. Further, the center lug grooves 21 connected to one outermost main groove 15 have all the same bending directions in the tire circumferential direction, and the center lug grooves 21 connected to different outermost main grooves 15 The bending directions of the tires in the circumferential direction are opposite to each other. The center lug groove 21 provided in this way has a groove depth within a range of 1 mm or more and 8 mm or less, and ends within the center land portion 41 from the end on the side connected to the outermost main groove 15. The groove width becomes narrower toward the end on the side of the sill.

Further, one end of the inner shoulder lug groove 23 is connected to the outermost main groove 15, and the other end is terminated in the shoulder land portion 45, and a plurality of the inner shoulder lug grooves 23 are formed side by side in the tire circumferential direction. That is, in the inner shoulder lug groove 23 located outside the outermost main groove 15 in the tire width direction, the inner end in the tire width direction is connected to the outermost main groove 15, and the outer end in the tire width direction is the shoulder land. It is terminated in the portion 45. Further, the inner shoulder lug groove 23 is inclined in the tire circumferential direction from the end side connected to the outermost main groove 15 toward the end side ending in the shoulder land portion 45 in the tire width direction. ing. The inner shoulder lug grooves 23 connected to one outermost main groove 15 have the same inclination direction in the tire circumferential direction, and the inner shoulder lug grooves 23 connected to different outermost main grooves 15 have the same inclination direction. In each case, the inclination directions in the tire circumferential direction when directed from the end on the outermost main groove 15 side toward the end in the shoulder land portion 45 are opposite to each other. The inner shoulder lug groove 23 provided in this way has a groove width within a range of 1 mm or more and 5 mm or less, and a groove depth within a range of 1 mm or more and 8 mm or less.

Further, the outer shoulder lug groove 26 extends in the tire width direction across the ground contact end T, and at least the inner end in the tire width direction is terminated within the shoulder land portion 45, and a plurality of the outer shoulder lug grooves 26 are lined up in the tire circumferential direction. It is formed. That is, the outer shoulder lug groove 26 is formed so as to straddle the ground contact end T by extending in the tire width direction at a position outside the inner shoulder lug groove 23 in the tire width direction. Further, the outer shoulder lug groove 26 is inclined in the tire circumferential direction while facing the tire width direction from the outer end side in the tire width direction toward the inner end side in the tire width direction, and is gently curved. There is. The outer shoulder lug grooves 26 arranged on both sides in the tire width direction have the same inclination directions in the tire circumferential direction among the outer shoulder lug grooves 26 arranged on the same direction side in the tire width direction. It has become. Further, the outer shoulder lug grooves 26 arranged on different directions in the tire width direction are inclined in the tire circumferential direction when the outer shoulder lug grooves 26 in the tire width direction are directed from the outer end side in the tire width direction to the inner end side in the tire width direction. The directions are opposite to each other. The outer shoulder lug groove 26 provided in this way has a groove width within a range of 1 mm or more and 8 mm or less, and a groove depth within a range of 1 mm or more and 8 mm or less.

The narrow groove 30 is an inner shoulder narrow groove that is arranged between the center narrow groove 31 located between the center main groove 11 and the outermost main groove 15 and the adjacent inner shoulder lug grooves 23 and extends in the tire width direction. It has a groove 32 and an outer shoulder narrow groove 36 that is arranged between adjacent outer shoulder lug grooves 26 and extends in the tire width direction across the ground contact end T. The narrow groove 30 in this case indicates a groove having a groove width of 3 mm or less, and includes a so-called sipe in which the groove walls come into contact with each other when a load is applied to the land portion 40 on which the fine groove 30 is formed.

Of the plurality of narrow grooves 30, the center fine groove 31 is formed so as to extend in the tire width direction and be inclined in the tire width direction, and both ends thereof are terminated in the center land portion 41. Further, the position of the center narrow groove 31 in the tire width direction is a position near the end portion 22 inside the center lug groove 21 in the tire width direction. That is, the center narrow groove 31 is formed so that the position in the tire width direction is within the range in which the center lug groove 21 is formed in the tire width direction, and the center lug groove 31 is not connected to the center lug groove 21. It is formed between adjacent center lug grooves 21. A plurality of center narrow grooves 31 are formed between the center lug grooves 21 adjacent to each other in this way.

Further, since the center narrow groove 31 is formed within the range in which the center lug groove 21 is formed in the tire width direction, the groove 5 is formed in the center land portion 41 over the entire circumference in the tire circumferential direction. It has a plain region 42 which is not a region. That is, the region in the tire width direction from the inner end 22 of the center lug groove 21 in the tire width direction to the top 12 of the center main groove 11 formed in a zigzag shape and protruding toward the center lug groove 21 is the center land. It is a plain area 42 of the unit 41. In other words, the inner end 43 in the tire width direction of the plane region 42 of the center land portion 41 is the position in the tire width direction of the top portion 12 of the center main groove 11 that protrudes toward the plane region 42. The outer end 43 in the tire width direction in the plane region 42 is located at the inner end 22 in the tire width direction of the center lug groove 21 in the tire width direction.

The end portion 22 of the center lug groove 21 is formed over a predetermined range by being formed in an arc shape or the like. Therefore, strictly speaking, the end portion 43 on the outer side in the tire width direction in the plane region 42 is located at the end portion 22 of the center lug groove 21 in the tire width direction of the innermost portion in the tire width direction. ..

Further, among the plurality of narrow grooves 30, the inner shoulder narrow groove 32 extends in the tire width direction and is inclined in the same direction as the inner shoulder lug groove 23 is inclined in the tire circumferential direction. Both ends are terminated within the shoulder land portion 45. The inner end of the inner shoulder narrow groove 32 in the tire width direction may be connected to the outermost main groove 15, and at least the outer end in the tire width direction should be terminated in the shoulder land portion 45. Just do it.

Further, among the plurality of narrow grooves 30, the outer shoulder narrow groove 36 extends in the tire width direction and is inclined in the same direction as the outer shoulder lug groove 26 is inclined in the tire circumferential direction. Both ends are terminated within the shoulder land portion 45. The outer shoulder groove 36 may be connected to a groove formed on the outer side in the tire width direction with respect to the ground contact end T at the inner end in the tire width direction, and at least the inner end in the tire width direction is connected to the outer shoulder groove 36. It suffices if it ends within the shoulder land portion 45.

FIG. 2 is a detailed view of part A of FIG. The inner shoulder lug groove 23 and the inner shoulder narrow groove 32 arranged on the outer side in the tire width direction from the outermost main groove 15 are similarly arranged on the outer side in the tire width direction with respect to the outermost main groove 15. All parts of the lug groove 26 and the outer shoulder narrow groove 36 are located inside in the tire width direction. That is, the inner shoulder lug groove end 24 which is the outer end of the inner shoulder lug groove 23 in the tire width direction and the inner shoulder narrow groove end 33 which is the outer end of the inner shoulder narrow groove 32 in the tire width direction are the outer shoulder. The outer shoulder lug groove end 27, which is the inner end of the lug groove 26 in the tire width direction, and the outer shoulder narrow groove end 37, which is the inner end of the outer shoulder narrow groove 36 in the tire width direction, are inward in the tire width direction. positioned.

Therefore, the shoulder land portion 45 extends over the entire circumference in the tire circumferential direction between the inner shoulder lug groove 23 and the inner shoulder narrow groove 32 in the tire width direction and the outer shoulder lug groove 26 and the outer shoulder narrow groove 36. It has a plane region 46, which is a region in which the groove 5 is not formed. That is, from the position in the tire width direction of the inner shoulder lug groove end portion 24 and the inner shoulder narrow groove end portion 33 on the side located outside in the tire width direction, the outer shoulder lug groove end portion 27 and the outer shoulder narrow groove end portion 37 The region in the tire width direction up to the position in the tire width direction on the side located inside in the tire width direction is the plain region 46 of the shoulder land portion 45.

In the present embodiment, the inner shoulder narrow groove end 33 is located outside the inner shoulder lug groove end 24 in the tire width direction, and the outer shoulder lug groove end 27 is closer to the tire than the outer shoulder narrow groove end 37. Since it is located inside in the width direction, the area in the tire width direction from the position of the inner shoulder narrow groove end 33 in the tire width direction to the position of the outer shoulder lug groove end 27 in the tire width direction is the plain area 46. ing. In other words, the inner end portion 47 in the tire width direction of the plain region 46 of the shoulder land portion 45 is positioned in the tire width direction of the inner shoulder narrow groove end portion 33, and the outer end portion in the tire width direction in the plane region 46. Reference numeral 47 is a position of the outer shoulder lug groove end portion 27 in the tire width direction.

The outer shoulder lug groove end portion 27 is formed over a predetermined range by being formed in an arc shape or the like. Therefore, strictly speaking, the outer end portion 47 in the tire width direction in the plane region 46 is a position in the tire width direction of the innermost portion in the tire width direction in the outer shoulder lug groove end portion 27.

The plane region 46 formed in this way is the width of the plane region 46 in the tire width direction when the distance between the outermost main groove 15 and the ground contact end T in the tire width direction is the ground contact width W1 of the shoulder land portion 45. W2 is in the range of 20% or more and 80% or less with respect to the ground contact width W1. That is, the relationship between the width W2 of the plane region 46 and the ground contact width W1 of the plane region 46 is within the range of 0.2 ≦ (W2 / W1) ≦ 0.8.

The width W2 of the plane region 46 is preferably in the range of 40% or more and 60% or less with respect to the ground contact width W1 of the shoulder land portion 45. That is, the relationship between the ground contact width W1 of the shoulder land portion 45 and the width W2 of the plane region 46 is preferably within the range of 0.4 ≦ (W2 / W1) ≦ 0.6.

Further, the plane region 46 is located at a position where the distance WL in the tire width direction from the outermost main groove 15 is within a range of 20% or more and 40% or less with respect to the ground contact width W1. That is, in the plane region 46, the relationship between the distance WL from the outermost main groove 15 of the end portion 47 inside the tire width direction in the plane region 46 and the ground contact width W1 of the shoulder land portion 45 is 0.2 ≦ (WL). / W1) It is located at a position within the range of ≦ 0.4.

Further, the outer shoulder lug groove 26 and the inner shoulder lug groove 23 are formed so that the relative positional relationship in the tire circumferential direction is within a predetermined range. Specifically, the outer shoulder lug groove 26 and the inner shoulder lug groove 23 have a distance L1 between the outer shoulder lug groove ends 27 of the outer shoulder lug grooves 26 adjacent to each other in the tire circumferential direction and a position in the tire circumferential direction. The distance L2 between the inner shoulder lug groove end 24 located between the outer shoulder lug groove ends 27 and the outer shoulder lug groove end 27 of any one of the outer shoulder lug groove ends 27 in the tire circumferential direction. , Is within the range of 0.2 ≦ (L2 / L1) ≦ 0.8.

That is, when focusing on one outer shoulder lug groove 26, the distance L1 is the outer shoulder lug groove end 27 of the outer shoulder lug groove 26 and the outer shoulder lug groove 26 adjacent to the outer shoulder lug groove 26. The distance from the outer shoulder lug groove end portion 27 in the tire circumferential direction. Further, the distance L2 is the inner shoulder lug groove end 24 in which the position in the tire circumferential direction is located between these outer shoulder lug groove ends 27, and the outer shoulder lug groove end 27 of the outer shoulder lug groove 26 of interest. It is the distance in the tire circumferential direction. In this case, the distance L2 between the outer shoulder lug groove end portion 27 and the inner shoulder lug groove end portion 24 in the tire circumferential direction is 20% or more and 80% with respect to the distance L1 between the outer shoulder lug groove end portions 27 in the tire circumferential direction. It is within the following range.

The distance L2 between the outer shoulder lug groove end portion 27 and the inner shoulder lug groove end portion 24 in the tire circumferential direction is 40% or more and 60% or less with respect to the distance L1 between the outer shoulder lug groove end portions 27 in the tire circumferential direction. It is preferably within the range of. That is, the relationship between the distance L1 and the distance L2 is preferably within the range of 0.4 ≦ (L2 / L1) ≦ 0.6.

FIG. 3 is an explanatory view of the relative positional relationship between the lengths of the lug groove and the narrow groove in the land portion of the shoulder. The outer shoulder lug groove 26 extends inward in the tire width direction from the outer shoulder narrow groove 36, and the distance in the tire width direction from the ground contact end T to the outer shoulder lug groove end 27 is the outer shoulder narrow groove from the ground contact end T. It is longer than the distance in the tire width direction to the groove end portion 37. Specifically, the outer shoulder lug groove 26 and the outer shoulder narrow groove 36 are the distance W3 in the tire width direction from the ground contact end T to the outer shoulder narrow groove end 37, and the tire from the ground contact end T to the outer shoulder lug groove end 27. The relationship with the distance W5 in the width direction is within the range of 0.2 ≦ (W3 / W5) ≦ 0.8. That is, the distance W3 in the tire width direction from the ground contact end T to the outer shoulder narrow groove end portion 37 is 20% or more and 80% or less with respect to the distance W5 in the tire width direction from the ground contact end T to the outer shoulder lug groove end portion 27. It is within the range of.

In this case, the distance W5 in the tire width direction from the ground contact end T to the outer shoulder lug groove end portion 27 is, strictly speaking, from the ground contact end T, similarly to the position of the end portion 47 of the plane region 46 of the shoulder land portion 45. The distance W5 in the tire width direction to the innermost portion in the tire width direction at the outer shoulder lug groove end portion 27 is set.

Further, the length of the inner shoulder lug groove 23 in the tire width direction is longer than the length of the inner shoulder narrow groove 32 in the tire width direction. Specifically, the inner shoulder lug groove 23 and the inner shoulder narrow groove 32 are the length W4 of the inner shoulder narrow groove 32 in the tire width direction and the tire width direction from the outermost main groove 15 to the inner shoulder lug groove end portion 24. The relationship with the distance W6 is within the range of 0.2 ≦ (W4 / W6) ≦ 0.8. That is, the length W4 of the inner shoulder narrow groove 32 in the tire width direction or the width W4 in the tire width direction is the distance W6 in the tire width direction from the outermost main groove 15 to the inner shoulder lug groove end portion 24, or the inner shoulder lug. It is within the range of 20% or more and 80% or less with respect to the width W6 of the groove 23 in the tire width direction.

In this case, the distance W6 in the tire width direction from the outermost main groove 15 to the inner shoulder lug groove end portion 24 is the same as the distance W5 in the tire width direction from the ground contact end T to the outer shoulder lug groove end portion 27. The distance W6 in the tire width direction from the groove 15 to the outermost portion of the inner shoulder lug groove end portion 24 in the tire width direction.

Further, the outer shoulder lug groove 26 and the outer shoulder narrow groove 36 are the two outer shoulder lug grooves 26 located on both sides of the outer shoulder narrow groove 36 in the tire circumferential direction and the outer shoulder narrow groove 36 in the respective tire circumferential directions. The distances are within a predetermined range. Specifically, the outer shoulder groove end 37 of the outer shoulder groove 36 and the outer shoulder lug groove 26 of one of the two outer shoulder lug grooves 26 adjacent to the outer shoulder groove 36 in the tire width direction. When the distance in the tire circumferential direction is L3 and the distance between the outer shoulder narrow groove end 37 and the other outer shoulder lug groove 26 in the tire circumferential direction is L4, the distance L3 and the distance L4 are 0.8 ≦ It is within the range of (L3 / L4) ≦ 1.2. That is, the distances L3 and L4 are the shortest distances between the outer shoulder narrow groove end portion 37 and the outer shoulder lug groove 26, respectively.

In this case, the distances L3 and L4 between the outer shoulder narrow groove end portion 37 and the outer shoulder lug groove 26 are the outer shoulder narrow groove end portion at the edge portion on the outer shoulder narrow groove end portion 37 side in the opening of the outer shoulder lug groove 26. It is the distance between the portion having the same position as the position in the tire width direction of 37 and the outer shoulder narrow groove end portion 37 in the tire circumferential direction. That is, the distance L3 between the outer shoulder narrow groove end portion 37 and one outer shoulder lug groove 26 in the tire circumferential direction is the distance L4 between the outer shoulder narrow groove end portion 37 and the other outer shoulder lug groove 26 in the tire circumferential direction. It is within the range of 80% or more and 120% or less. In other words, the outer shoulder narrow grooves 36 are arranged near the center position in the tire circumferential direction between the outer shoulder lug grooves 26 adjacent to each other.

Similarly, the inner shoulder lug groove 23 and the inner shoulder narrow groove 32 are the tire circumferential directions of the two inner shoulder lug grooves 23 and the inner shoulder narrow groove 32 located on both sides of the inner shoulder narrow groove 32 in the tire circumferential direction. The distances between the tires are within a predetermined range. Specifically, the tire of the inner shoulder lug groove end 24 of one of the two inner shoulder lug grooves 23 adjacent to the inner shoulder groove 32 in the tire width direction and the inner shoulder lug groove 32. When the distance in the circumferential direction is L5 and the distance between the inner shoulder lug groove end 24 of the other inner shoulder lug groove 23 and the inner shoulder narrow groove 32 in the tire circumferential direction is L6, the distance L5 and the distance L6 are 0. It is within the range of .8 ≦ (L5 / L6) ≦ 1.2.

That is, the distance L5 between the inner shoulder lug groove end 24 of one inner shoulder lug groove 23 and the inner shoulder narrow groove 32 in the tire circumferential direction is the inner shoulder lug groove end 24 of the other inner shoulder lug groove 23 and the inner shoulder narrow groove 32. It is within the range of 80% or more and 120% or less with respect to the distance L6 from the groove 32 in the tire circumferential direction. In other words, the inner shoulder narrow groove 32 is arranged near the center position in the tire circumferential direction between the inner shoulder lug grooves 23 adjacent to each other.

FIG. 4 is an explanatory view of a region in the land portion of the shoulder where the outer shoulder lug groove is not provided. The outer shoulder lug groove 26 is provided so that the region of the shoulder land portion 45 where the outer shoulder lug groove 26 is not formed is within a predetermined range with respect to the region where the outer shoulder lug groove 26 is formed. .. Specifically, the area of the outer rectangle 51, which is a rectangle 50 with the four ends of the two outer shoulder lug grooves 26 adjacent to each other as the corners 52, is S1, and the outer rectangle 51 is formed. Of the two sides 53, two intersections 66 of the extension line 65 and the outermost main groove 15 in which the two sides 53 connecting the ends of one outer shoulder lug groove 26 are extended toward the outermost main groove 15 are extended. And, when the area of the inner rectangle 61, which is a rectangle 50 in which the two outer shoulder lug groove ends 27 of the two outer shoulder lug grooves 26 are corners 62, respectively, is S2, the areas S1 and S2 are The relationship is within the range of 1 ≦ (S2 / S1) ≦ 1.3.

Of these, the corner portion 52 of the outer rectangular 51 has the midpoint of the groove opening at the outer end of one outer shoulder lug groove 26 in the tire width direction as P1, and the outer shoulder lug groove end of the outer shoulder lug groove 26. The midpoint of the groove opening in 27 is P2, the midpoint of the groove opening at the outer end of the other outer shoulder lug groove 26 in the tire width direction is P1', and the outer shoulder lug groove end of the outer shoulder lug groove 26. The midpoints P1, P2, P1', and P2'when the midpoint of the groove opening in the portion 27 is P2'. In other words, the outer rectangle 51 becomes a rectangle 50 in which the midpoints P1, P2, P1', and P2'are connected by four sides 53, and the positions of the midpoints P1, P2, P1', and P2'are the corners 52. ing.

Further, the corner portion 62 of the inner rectangular 61 has an extension line 65 in which the side 53 connecting the midpoint P1 and the midpoint P2 of the outer rectangular 51 is extended toward the outermost main groove 15, and the opening of the outermost main groove 15. The intersection 66 with the outer portion in the tire width direction is set as the point P3, and the extension line 65 extending the side 53 connecting the midpoint P1'and the midpoint P2' of the outer rectangular 51 toward the outermost main groove 15 and the most The points P2, midpoint P2', point P3, and point P3'when the intersection 66 with the outer portion in the tire width direction at the opening of the outer main groove 15 is set to point P3'. In other words, the inner rectangle 61 connects the midpoint P2, the midpoint P2', the point P3, and the point P3' by four sides 63, and corners the positions of the midpoint P2, the midpoint P2', the point P3, and the point P3'. It is a rectangle 50 as a portion 62. The outer shoulder lug groove 26 is formed so that the area S2 of the inner rectangle 61 defined as described above is within a range of 100% or more and 130% or less with respect to the area S1 of the outer rectangle 51.

5 and 6 are modified examples of the pneumatic tire according to the embodiment, and are explanatory views when the inner shoulder narrow groove end portion is located outside the inner shoulder lug groove end portion in the tire width direction. In the above-described embodiment, the inner shoulder narrow groove end 33 is located outside the inner shoulder lug groove end 24 in the tire width direction, but on the contrary, it is inside the inner shoulder narrow groove end 33. The shoulder lug groove end 24 may be located outside in the tire width direction. That is, by disposing the inner shoulder narrow groove 32 at a position where the inner end of the inner shoulder narrow groove 32 in the tire width direction is connected to the outermost main groove 15, the inner shoulder narrow groove end 33 becomes the inner shoulder lug. It may be located inside the groove end portion 24 in the tire width direction. In this case, as shown in FIG. 5, the relative positional relationship between the inner shoulder groove 32 and the two inner shoulder lug grooves 23 adjacent to the inner shoulder groove 32 in the tire width direction is the inner shoulder. The distance between the lug groove end portion 24 and one of the two inner shoulder lug grooves 23 in the tire circumferential direction is L5, and the tire between the inner shoulder narrow groove end portion 33 and the other inner shoulder lug groove 23. It is preferable that the distance L5 and the distance L6 are within the range of 0.8 ≦ (L5 / L6) ≦ 1.2, where L6 is the distance in the circumferential direction. In other words, the distance L5 between one inner shoulder lug groove 23 and the inner shoulder narrow groove end 33 in the tire circumferential direction becomes the distance L6 between the other inner shoulder lug groove 23 and the inner shoulder narrow groove end 33 in the tire circumferential direction. On the other hand, it is preferably in the range of 80% or more and 120% or less.

That is, the distance L5 and the distance L6 are the inner shoulder lug groove ends of the inner shoulder lug groove 23 at the inner shoulder groove 32 and the two inner shoulder lug grooves 23 adjacent to the inner shoulder groove 32 in the tire width direction. When the inner shoulder narrow groove end 33 of the inner shoulder narrow groove 32 is located outside in the tire width direction as compared with the portion 24, one of the inner shoulder lug groove end 24 and the inner shoulder narrow groove 32 is located in the tire circumferential direction. Let L5 be the distance, and let L6 be the distance between the other inner shoulder lug groove end 24 and the inner shoulder narrow groove 32 in the tire circumferential direction. Further, when the inner shoulder narrow groove end 33 of the inner shoulder narrow groove 32 is located inside in the tire width direction than the inner shoulder lug groove end 24 of the inner shoulder lug groove 23, it is one with the inner shoulder lug groove end 24. The distance between the inner shoulder lug groove 23 and the tire circumferential direction is L5, and the distance between the inner shoulder narrow groove end 33 and the other inner shoulder lug groove 23 in the tire circumferential direction is L6. When the distance L5 and the distance L6 are defined in this way, the inner shoulder lug groove 23 and the inner side have any positional relationship between the inner shoulder lug groove end portion 24 and the inner shoulder narrow groove end portion 33 in the tire width direction. The shoulder groove 32 is preferably formed so that the distance L5 and the distance L6 are within the range of 0.8 ≦ (L5 / L6) ≦ 1.2.

Further, when the inner shoulder lug groove end 24 is located outside the tire width direction than the inner shoulder narrow groove end 33, the plain region 46 of the shoulder land portion 45 is the outer shoulder lug as shown in FIG. The region in the tire width direction from the position of the groove end portion 27 in the tire width direction to the position of the inner shoulder lug groove end portion 24 in the tire width direction is the plain region 46. That is, in this case, the outer end portion 47 in the tire width direction of the plain region 46 of the shoulder land portion 45 is located at the position of the outer shoulder lug groove end portion 27 in the tire width direction, and the inner end in the tire width direction in the plane region 46. The portion 47 is located at the inner shoulder lug groove end portion 24 in the tire width direction.

Since the inner shoulder lug groove end 24 is formed over a predetermined range by being formed in an arc shape or the like, the inner end 47 in the tire width direction in the plane region 46 is strictly defined. It is the position in the tire width direction of the outermost portion in the tire width direction at the inner shoulder lug groove end portion 24.

As described above, even when the position of the inner shoulder lug groove end portion 24 in the tire width direction is the position of the inner end portion 47 of the plain region 46 in the tire width direction, the width W2 of the plane region 46 in the tire width direction is determined. It is within the range of 20% or more and 80% or less with respect to the ground contact width W1. Further, also in this case, in the plane region 46, the relationship between the distance WL from the outermost main groove 15 of the end portion 47 on the inner side in the tire width direction and the ground contact width W1 of the shoulder land portion 45 is 0.2 ≦ ( It is located at a position within the range of WL / W1) ≦ 0.4.

Further, in the above-described embodiment, the outer shoulder lug groove end portion 27 is located inside in the tire width direction as compared with the outer shoulder narrow groove end portion 37, but the outer shoulder narrow groove end portion 37 is located more than the outer shoulder lug groove end portion 27. May be located inside in the tire width direction. That is, the position of the outer end portion 47 of the plain region 46 provided on the shoulder land portion 45 in the tire width direction in the tire width direction may be the position of the outer shoulder narrow groove end portion 37 in the tire width direction.

Further, in the above-described embodiment, one outer shoulder groove 36 is provided between the adjacent outer shoulder lug grooves 26, but the outer shoulder groove 36 is provided between the adjacent outer shoulder lug grooves 26. A plurality of them may be provided between them. In this case, the relationship between the distance W3 from the ground contact end T to the outer shoulder narrow groove end 37 and the distance W5 from the ground contact end T to the outer shoulder lug groove end 27 is the outer shoulder among the plurality of outer shoulder narrow grooves 36. The distance W3 between the outer shoulder narrow groove end 37 of the outer shoulder narrow groove 36 where the narrow groove end 37 is located most inward in the tire width direction and the ground contact end T is 0.2 ≦ (W3 / W5) ≦ with respect to the distance W5. It may be within the range of 0.8. Similarly, the distances L3 and L4 between the outer shoulder groove end 37 and the outer shoulder lug groove 26 are the outer shoulders in which the outer shoulder groove end 37 is located most inward in the tire width direction among the plurality of outer shoulder groove 36s. The distances L3 and L4 between the outer shoulder narrow groove end 37 of the narrow groove 36 and the outer shoulder lug groove 26 may be within the range of 0.8 ≦ (L3 / L4) ≦ 1.2.

Similarly, a plurality of inner shoulder lug grooves 32 may be provided between adjacent inner shoulder lug grooves 23. In this case, the relationship between the length W4 of the inner shoulder groove 32 in the tire width direction and the distance W6 from the outermost main groove 15 to the inner shoulder lug groove end 24 is the tire among the plurality of inner shoulder grooves 32. The length W4 of the inner shoulder groove 32 having the longest length in the width direction in the tire width direction may be within the range of 0.2 ≦ (W4 / W6) ≦ 0.8 with respect to the distance W6. Similarly, when the inner shoulder narrow groove end portions 33 of the plurality of inner shoulder narrow groove 32s are all located inside the inner shoulder lug groove end portion 24 in the tire width direction, the inner shoulder narrow groove end portion 33 and the inner shoulder lug groove are similarly located. The distances L5 and L6 from 23 are the inner shoulder groove end 33 and the inner shoulder lug of the inner shoulder groove 32 in which the inner shoulder groove end 33 is located most outward in the tire width direction among the plurality of inner shoulder groove 32s. The distances L5 and L6 from the groove 23 may be within the range of 0.8 ≦ (L5 / L6) ≦ 1.2.

When the pneumatic tire 1 configured as described above is mounted on the vehicle and traveled, the pneumatic tire 1 rotates while the tread surface 3 located below the tread surface 3 is in contact with the road surface. When traveling on a dry road surface with a vehicle equipped with pneumatic tires 1, the driving force and braking force are transmitted to the road surface and turning force is generated mainly by the frictional force between the tread surface 3 and the road surface. It runs by letting it run. Further, when traveling on a wet road surface, water between the tread surface 3 and the road surface enters the grooves 5 such as the main groove 10 and the lug groove 20, and these grooves 5 are between the tread surface 3 and the road surface. Run while draining the water. As a result, the tread surface 3 can easily come into contact with the road surface, and the frictional force between the tread surface 3 and the road surface enables the vehicle to travel.

Various grooves 5 are formed on the tread surface 3 of the pneumatic tire 1 in order to ensure drainage on such a wet road surface, and the main groove 10 and the lug groove 20 in the land portion 40 are formed. The portion in the vicinity of the portion where the tires are formed has low rigidity due to these grooves 5. Therefore, when the land portion 40 touches the road surface while the vehicle is traveling, the portion of the land portion 40 in the vicinity of the groove 5 is easily deformed by the load received from the road surface. In particular, the shoulder land portion 45 is susceptible to a large load when the vehicle turns.

On the other hand, the shoulder land portion 45 is provided with a plain region 46 which is a region in which the groove 5 is not formed over the entire circumference in the tire circumferential direction. The plain region 46 in the shoulder land portion 45 has rigidity because the groove 5 is not formed, and is less likely to be deformed even when a load is applied to the shoulder land portion 45. Further, the plane region 46 is provided near the ground contact end T on the ground contact surface of the shoulder land portion 45. Therefore, for example, even when a large load is applied to the shoulder land portion 45 when the vehicle is turning, the plane region 46 where the rigidity is ensured can receive the load without being significantly deformed, and the rigidity near the ground contact end T can be increased. Since it can be secured, the maneuverability can be ensured.

Further, since the lug groove 20 and the narrow groove 30 are formed on both sides of the plane region 46 in the tire width direction, the plane region 46 is maintained while ensuring the rigidity of the shoulder land portion 45 for ensuring maneuverability. On both sides in the tire width direction of the tire, it is possible to give appropriate elasticity. As a result, it is possible to suppress the application of a large load to a part of the tread surface 3, and it is possible to suppress local wear, so that uneven wear resistance can be ensured.

Further, in the plain region 46, since the width W2 in the tire width direction is within the range of 20% or more and 80% or less of the ground contact width W1 of the shoulder land portion 45, uneven wear is performed while improving the rigidity of the shoulder land portion 45. Can be suppressed. That is, when the width W2 of the plane region 46 is less than 20% of the ground contact width W1 of the shoulder land portion 45, it is difficult to effectively improve the rigidity of the shoulder land portion 45 even by providing the plane region 46. become. Further, when the width W2 of the plane region 46 is larger than 80% of the ground contact width W1 of the shoulder land portion 45, the rigidity of the shoulder land portion 45 becomes too high, and uneven wear occurs due to local wear. There is a risk. On the other hand, when the width W2 of the plane region 46 is 20% or more and 80% or less of the ground contact width W1 of the shoulder land portion 45, the rigidity of the shoulder land portion 45 is improved without causing uneven wear. Can be done. As a result, both maneuverability and uneven wear resistance can be achieved at the same time.

Further, the plane region 46 is formed at a position where the distance WL in the tire width direction from the outermost main groove 15 is within a range of 20% or more and 40% or less with respect to the ground contact width W1 of the shoulder land portion 45. Therefore, the rigidity of the shoulder land portion 45 can be improved while suppressing uneven wear more reliably. That is, when the distance WL between the outermost main groove 15 and the plane region 46 is less than 20% with respect to the ground contact width W1 of the shoulder land portion 45, the plane region 46 is too close to the outermost main groove 15 and the tire. Since it is located too inward in the width direction, it may be difficult to effectively improve the rigidity of the shoulder land portion 45. Further, when the distance WL between the outermost main groove 15 and the plane region 46 is larger than 40% with respect to the ground contact width W1 of the shoulder land portion 45, the plane region 46 is too close to the ground contact end T having a high ground pressure. Therefore, the rigidity near the ground contact end T becomes too high, and it may be difficult to suppress uneven wear. On the other hand, when the distance WL between the outermost main groove 15 and the plane region 46 is within the range of 20% or more and 40% or less with respect to the ground contact width W1 of the shoulder land portion 45, uneven wear is appropriately performed. While suppressing it, the rigidity of the shoulder land portion 45 can be effectively improved. As a result, both safety and uneven wear resistance can be more reliably achieved.

Further, the relationship between the distance L1 between the outer shoulder lug groove end portions 27 adjacent to each other in the tire circumferential direction in the tire circumferential direction and the distance L2 between the outer shoulder lug groove end portion 27 and the inner shoulder lug groove end portion 24 in the tire circumferential direction is as follows. Since it is within the range of 0.2 ≦ (L2 / L1) ≦ 0.8, it is possible to suppress the occurrence of a portion having low rigidity in the plane region 46. That is, when (L2 / L1) <0.2 or (L2 / L1)> 0.8, the distance between the inner shoulder lug groove 23 and the outer shoulder lug groove 26 is too close. The rigidity between the inner shoulder lug groove 23 and the outer shoulder lug groove 26 becomes low, and it may be difficult to effectively improve the maneuverability. Further, in this case, since the difference in rigidity from the position away from the inner shoulder lug groove 23 and the outer shoulder lug groove 26 in the plane region 46 becomes large, the effect of improving the uneven wear resistance may be reduced. On the other hand, when the relationship between the distance L1 and the distance L2 is within the range of 0.2 ≦ (L2 / L1) ≦ 0.8, the distance between the inner shoulder lug groove 23 and the outer shoulder lug groove 26 is close. Since it is possible to suppress the excessive rigidity, it is possible to suppress the occurrence of a portion where the rigidity becomes low in the plane region 46, and it is possible to suppress that the rigidity difference becomes too large. As a result, both maneuverability and uneven wear resistance can be more reliably achieved.

Further, the relationship between the distance W3 in the tire width direction from the ground contact end T to the outer shoulder narrow groove end portion 37 and the distance W5 in the tire width direction from the ground contact end T to the outer shoulder lug groove end portion 27 is 0.2 ≦ (W3). / W5) Since it is within the range of ≦ 0.8, the rigidity of the portion of the shoulder land portion 45 between the plane region 46 and the ground contact end T can be made appropriately large. That is, when (W3 / W5) <0.2, the outer shoulder narrow groove 36 is too short with respect to the outer shoulder lug groove 26, so that between the plane region 46 and the ground contact end T in the shoulder land portion 45. It becomes difficult to moderately relax the rigidity of the part, and it may be difficult to suppress uneven wear. Further, when (W3 / W5)> 0.8, the outer shoulder narrow groove 36 is too long with respect to the outer shoulder lug groove 26, so that the rigidity of the portion between the plane region 46 and the ground contact end T becomes high. It becomes low, and it may be difficult to effectively improve the rigidity of the shoulder land portion 45. On the other hand, when the relationship between the distance W3 and the distance W5 is within the range of 0.2 ≦ (W3 / W5) ≦ 0.8, the length of the outer shoulder narrow groove 36 with respect to the outer shoulder lug groove 26 is set. Since the length can be made appropriate, the rigidity of the portion between the plane region 46 and the ground contact end T in the shoulder land portion 45 can be made appropriate, and the shoulder land portion can be suppressed while suppressing uneven wear. The rigidity of 45 can be secured. As a result, both maneuverability and uneven wear resistance can be more reliably achieved.

Further, the relationship between the length W4 of the inner shoulder narrow groove 32 in the tire width direction and the distance W6 in the tire width direction from the outermost main groove 15 to the inner shoulder lug groove end 24 is 0.2 ≦ (W4 / W6). Since it is within the range of ≦ 0.8, the rigidity of the portion between the plane region 46 and the outermost main groove 15 in the shoulder land portion 45 can be made appropriately large. That is, when (W4 / W6) <0.2, the inner shoulder narrow groove 32 is too short with respect to the inner shoulder lug groove 23, so that the plain region 46 and the outermost main groove 15 in the shoulder land portion 45 It becomes difficult to moderately relax the rigidity of the part between them, and it may be difficult to suppress uneven wear. Further, when (W4 / W6)> 0.8, the inner shoulder narrow groove 32 is too long with respect to the inner shoulder lug groove 23, so that the portion between the plane region 46 and the outermost main groove 15 is formed. The rigidity becomes low, and it may be difficult to effectively improve the rigidity of the shoulder land portion 45. On the other hand, when the relationship between the length W4 and the distance W6 is within the range of 0.2 ≦ (W4 / W6) ≦ 0.8, the length of the inner shoulder narrow groove 32 with respect to the inner shoulder lug groove 23 Is able to have an appropriate length, so that the rigidity of the portion between the plane region 46 and the outermost main groove 15 in the shoulder land portion 45 can be made an appropriate size, and uneven wear can be suppressed while suppressing uneven wear. The rigidity of the shoulder land portion 45 can be ensured. As a result, both maneuverability and uneven wear resistance can be more reliably achieved.

Further, the distance L3 between the outer shoulder lug groove 26 of one of the two outer shoulder lug grooves 26 adjacent to the outer shoulder narrow groove 36 in the tire width direction and the outer shoulder narrow groove end portion 37 in the tire circumferential direction is determined. Since the distance L4 between the other outer shoulder lug groove 26 and the outer shoulder narrow groove end portion 37 in the tire circumferential direction is within the range of 0.8 ≦ (L3 / L4) ≦ 1.2, the plane in the shoulder land portion 45. It is possible to suppress the occurrence of a rigidity difference in the region between the region 46 and the grounding end T. That is, when (L3 / L4) <0.8 or (L3 / L4)> 1.2, the rigidity is formed in the region between the plane region 46 and the ground contact end T in the shoulder land portion 45. Differences can occur, resulting in too low rigidity and uneven wear. On the other hand, when the relationship between the distance L3 and the distance L4 is within the range of 0.8 ≦ (L3 / L4) ≦ 1.2, between the plane region 46 and the ground contact end T in the shoulder land portion 45. It is possible to suppress the occurrence of a rigidity difference in the region of the above, and it is possible to suppress uneven wear while ensuring the rigidity of the shoulder land portion 45. As a result, both maneuverability and uneven wear resistance can be more reliably achieved.

Further, in the inner shoulder groove 32 and the two inner shoulder lug grooves 23 adjacent to the inner shoulder groove 32 in the tire width direction, the tire of one inner shoulder lug groove end 24 and the inner shoulder groove 32. The distance L5 in the circumferential direction and the distance between the other inner shoulder lug groove end 24 and the inner shoulder narrow groove 32 in the tire circumferential direction are L6, or the tire between the inner shoulder lug groove end 24 and one inner shoulder lug groove 23. The distance L5 in the circumferential direction and the distance L6 between the inner shoulder narrow groove end 33 and the other inner shoulder lug groove 23 in the tire circumferential direction are within the range of 0.8 ≦ (L5 / L6) ≦ 1.2. Therefore, it is possible to suppress the occurrence of a rigidity difference in the region between the plane region 46 and the outermost main groove 15 in the shoulder land portion 45. That is, when (L5 / L6) <0.8 or (L5 / L6)> 1.2, the region between the plane region 46 and the outermost main groove 15 in the shoulder land portion 45. There is a possibility that the rigidity will be different and the rigidity will be too low or uneven wear will occur. On the other hand, when the relationship between the distance L5 and the distance L6 is within the range of 0.8 ≦ (L5 / L6) ≦ 1.2, the plane region 46 and the outermost main groove 15 in the shoulder land portion 45 It is possible to suppress the occurrence of a rigidity difference in the region between the two, and it is possible to suppress uneven wear while ensuring the rigidity of the shoulder land portion 45. As a result, both maneuverability and uneven wear resistance can be more reliably achieved.

Further, an area S1 of the outer rectangle 51 having both ends of the two outer shoulder lug grooves 26 adjacent to each other as corner portions 52, and an extension line 65 extending the side 53 of the outer rectangle 51 toward the outermost main groove 15. Because the relationship between the intersection 66 with the outermost main groove 15 and the area S2 of the inner rectangle 61 as the corner 62 between the outer shoulder lug groove end 27 is within the range of 1 ≦ (S2 / S1) ≦ 1.3. When the plain area 46 is provided on the shoulder land portion 45, the rigidity can be appropriately increased. That is, when (S2 / S1) <1, the outer shoulder lug groove 26 is too long in the tire width direction and the inner direction, so that it becomes difficult to effectively secure the rigidity of the shoulder land portion 45, and the operation is performed. It can be difficult to ensure safety. Further, when (S2 / S1)> 1.3, the outer shoulder lug groove 26 is too short, so that the rigidity of the shoulder land portion 45 becomes too high when the plain region 46 is provided on the shoulder land portion 45. It can be difficult to control uneven wear. On the other hand, when the relationship between the area S1 and the area S2 is within the range of 1 ≦ (S2 / S1) ≦ 1.3, the length of the outer shoulder lug groove 26 can be set to an appropriate length. Therefore, the rigidity when the plain region 46 is provided on the shoulder land portion 45 can be made to an appropriate size, and the rigidity of the shoulder land portion 45 can be ensured while suppressing uneven wear. As a result, both maneuverability and uneven wear resistance can be more reliably achieved.

Further, the center land portion 41 is also provided with a plane region 42 which is a region in which the groove 5 is not formed over the entire circumference in the tire circumferential direction, and the center land portion 41 has the rigidity of the portion of the plane region 42. Is high. Therefore, even when a large load is applied to the center land portion 41, the plane region 42 is hardly deformed significantly, so that the center land portion 41 can receive the load without being significantly deformed. As a result, the rigidity near the center in the tire width direction in the ground contact region of the pneumatic tire 1 can be ensured, and the maneuverability can be ensured. Further, since the center main groove 11, the center lug groove 21, and the center narrow groove 31 are formed on both sides of the plane region 42 in the tire width direction, the rigidity of the center land portion 41 for ensuring maneuverability is high. While ensuring, it is possible to provide appropriate elasticity on both sides of the plain region 42 in the tire width direction and suppress uneven wear. As a result, both maneuverability and uneven wear resistance can be more reliably achieved.

〔Example〕
7A and 7B are charts showing the results of performance tests of pneumatic tires. Hereinafter, the performance evaluation test of the above-mentioned pneumatic tire 1 with respect to the conventional pneumatic tire 1 and the pneumatic tire 1 according to the present invention will be described. The performance evaluation test was conducted for maneuverability and uneven wear resistance.

In the performance evaluation test, the tire nominal specified by JATTA is 145 / 80R12 80 / 78N size pneumatic tire 1 is assembled to the rim wheel of 12x4.00B size JATTA standard rim and the air pressure is adjusted to 260kPa. The test run was carried out by mounting a light commercial vehicle on the test vehicle as a test vehicle. The evaluation method of each test item was performed by a panelist driving a vehicle equipped with a pneumatic tire 1 for which an evaluation test is to be performed and performing a sensory evaluation by the panelist. The maneuverability is displayed with a score of 100 in the conventional example described later, and the larger the value, the better the maneuverability. The uneven wear resistance was evaluated by measuring the amount of heel and toe wear on the shoulder land 45 after traveling 10,000 km and indexing the reciprocal of the measured value. The uneven wear resistance is represented by an index of 100 in the conventional example described later, and the larger the value, the better the uneven wear resistance.

The evaluation test compares the conventional pneumatic tire 1, which is an example of the conventional pneumatic tire 1, the pneumatic tires 1 according to the present invention, Examples 1 to 14, and the pneumatic tire 1 according to the present invention. 17 types of pneumatic tires 1 of Comparative Examples 1 and 2, which are pneumatic tires 1 to be used, were subjected to the above. Among these pneumatic tires 1, the conventional pneumatic tire 1 is not provided with a plain region 46 on the shoulder land portion 45. Further, in the pneumatic tires 1 of Comparative Examples 1 and 2, the plane region 46 is provided on the shoulder land portion 45, but the ratio of the width W2 of the plane region 46 to the ground contact width W1 of the shoulder land portion 45 is 0. It is out of the range of 2 ≦ (W2 / W1) ≦ 0.8.

On the other hand, in Examples 1 to 14, which are examples of the pneumatic tire 1 according to the present invention, the plain area 46 is provided on the shoulder land portion 45, and the plane region 46 with respect to the ground contact width W1 of the shoulder land portion 45. The ratio of the width W2 of is within the range of 0.2 ≦ (W2 / W1) ≦ 0.8. Further, the pneumatic tires 1 according to Examples 1 to 14 have different relative lengths and intervals of the inner shoulder lug groove 23, the outer shoulder lug groove 26, the inner shoulder groove 32, and the outer shoulder groove 36. There is.

As a result of conducting an evaluation test using these pneumatic tires 1, as shown in FIGS. 7A and 7B, the pneumatic tires 1 of Examples 1 to 14 were compared with the conventional examples and Comparative Examples 1 and 2. It was found that both the maneuverability and the uneven wear resistance can be improved. That is, the pneumatic tire 1 according to Examples 1 to 14 can have both maneuverability and uneven wear resistance.

1 Pneumatic tire 2 Tread part 3 Tread surface 5 Groove 10 Main groove 11 Center main groove 12 Top 15 Outer main groove 20 Rug groove 21 Center lug groove 22 End 23 Inner shoulder lug groove 24 Inner shoulder lug groove End 26 Outer shoulder Rug groove 27 Outer shoulder lug groove end 30 Fine groove 31 Center fine groove 32 Inner shoulder fine groove 33 Inner shoulder narrow groove end 36 Outer shoulder narrow groove 37 Outer shoulder narrow groove end 40 Land 41 Center land 42, 46 Plain area 43 , 47 End 45 Shoulder Land 50 Rectangle 51 Outer Rectangle 52, 62 Corner 53, 63 Side 61 Inner Rectangle 65 Extension Line 66 Intersection

Claims (6)

Three main grooves formed on the tread surface and extending in the tire circumferential direction,
Of the three main grooves, the outermost main groove located on the outermost side in the tire width direction, the outermost main groove, located on the outer side in the tire width direction, adjacent to the outermost main groove, and the shoulder land through which the ground contact end passes. Department and
Of the three main grooves, the center main groove, which is located on the equatorial plane of the tire, is located on both sides in the tire width direction and is divided by the center main groove and the outermost main groove. Department and
A plurality of inner shoulder lug grooves extending in the tire width direction, one end connected to the outermost main groove, and the other end ending in the shoulder land portion.
A plurality of inner shoulder grooves that are arranged between adjacent inner shoulder lug grooves and extend in the tire width direction, and at least the outer end in the tire width direction terminates in the shoulder land portion.
A plurality of outer shoulder lug grooves that extend in the tire width direction across the ground contact end and at least the inner end in the tire width direction terminates in the shoulder land portion.
A plurality of outer shoulder narrow grooves that are arranged between adjacent outer shoulder lug grooves and extend in the tire width direction across the ground contact end, and at least the inner end in the tire width direction terminates in the shoulder land portion. When,
A center located between the center main groove and the outermost main groove, the outer end in the tire width direction is connected to the outermost main groove, and the inner end in the tire width direction is terminated in the center land portion. With a lug groove
With
The inner shoulder lug groove end portion which is the outer end portion of the inner shoulder lug groove in the tire width direction and the inner shoulder narrow groove end portion which is the outer end portion of the inner shoulder narrow groove in the tire width direction are the outer shoulder lug groove. It is located inside the tire width direction with respect to the outer shoulder lug groove end which is the inner end in the tire width direction and the outer shoulder narrow groove end which is the inner end in the tire width direction of the outer shoulder groove.
The shoulder land portion has a groove extending over the entire circumference in the tire circumferential direction between the inner shoulder lug groove and the inner shoulder narrow groove in the tire width direction and the outer shoulder lug groove and the outer shoulder narrow groove. It has a plain area, which is an unformed area,
When the distance between the outermost main groove and the ground contact end in the tire width direction is the ground contact width W1 of the shoulder land portion, the plane region of the shoulder land portion has a width W2 in the tire width direction and the ground contact. range der following 20% to 80% of the width W1 is,
The center main groove is formed in a zigzag shape that repeats unevenness in the tire width direction while extending in the tire circumferential direction.
The center land portion has a plain region of the center land portion, which is a region in which a groove is not formed over the entire circumference in the tire circumferential direction.
The plain region of the center land portion is in the tire width direction from the inner end of the center lug groove in the tire width direction to the top of the center main groove formed in a zigzag shape so as to project toward the center lug groove side. Pneumatic tires characterized by being in the area . The plain region of the shoulder land portion is located at a position where the distance WL in the tire width direction from the outermost main groove is within a range of 20% or more and 40% or less with respect to the ground contact width W1. Item 1. The pneumatic tire according to item 1. The distance L1 between the ends of the outer shoulder lug grooves adjacent to each other in the tire circumferential direction,
The tire circumferential direction between the inner shoulder lug groove end portion located between the outer shoulder lug groove end portions and the outer shoulder lug groove end portion of any one of the outer shoulder lug groove end portions. The relationship with the distance L2 in
The pneumatic tire according to claim 1 or 2, which is in the range of 0.2 ≦ (L2 / L1) ≦ 0.8. The distance W3 in the tire width direction from the ground contact end to the outer shoulder groove end,
The distance W5 in the tire width direction from the ground contact end to the outer shoulder lug groove end,
The relationship is within the range of 0.2 ≦ (W3 / W5) ≦ 0.8.
The length W4 of the inner shoulder groove in the tire width direction and
The distance W6 in the tire width direction from the outermost main groove to the end of the inner shoulder lug groove,
The pneumatic tire according to any one of claims 1 to 3, wherein the relationship is within the range of 0.2 ≦ (W4 / W6) ≦ 0.8. In two of the inner shoulder lug grooves adjacent in the tire width direction relative to the previous SL inner shoulder narrow groove and the inner shoulder narrow groove,
Of the two inner shoulder lug grooves, when the inner shoulder narrow groove end of the inner shoulder narrow groove is located on the outer side in the tire width direction than the inner shoulder lug groove end of the inner shoulder lug groove. The distance between the inner shoulder lug groove end of one of the inner shoulder lug grooves and the inner shoulder narrow groove in the tire circumferential direction is L5, and the inner shoulder lug groove end of the other inner shoulder lug groove and the inner shoulder narrow groove. Assuming that the distance from the groove in the tire circumferential direction is L6, the distance L5 and the distance L6 are within the range of 0.8 ≦ (L5 / L6) ≦ 1.2.
When the inner shoulder narrow groove end of the inner shoulder narrow groove is located inside in the tire width direction than the inner shoulder lug groove end of the inner shoulder lug groove, the inner shoulder narrow groove end and the two said The distance between one of the inner shoulder lug grooves and the inner shoulder lug groove in the tire circumferential direction is L5, and the distance between the inner shoulder narrow groove end and the other inner shoulder lug groove in the tire circumferential direction is L6. The pneumatic tire according to any one of claims 1 to 4, wherein the distance L5 and the distance L6 are within the range of 0.8 ≦ (L5 / L6) ≦ 1.2. Let S1 be the area of a rectangle whose corners are four ends consisting of both ends of the two outer shoulder lug grooves adjacent to each other.
Of the four sides forming the rectangle, the extension line extending the two sides connecting the ends of each of the outer shoulder lug grooves toward the outermost main groove and the outermost main groove When the area of the rectangle whose corners are the two intersections and the two outer shoulder lug groove ends of the two outer shoulder lug grooves is S2.
The pneumatic tire according to any one of claims 1 to 5, wherein the area S1 and the area S2 have a relationship within the range of 1 ≦ (S2 / S1) ≦ 1.3.

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