JP2017202724A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of achieving both of operation stability and uneven wear resistance.SOLUTION: A pneumatic tire includes: inside shoulder lug grooves 23 which each have one end connected to an outermost main groove 15; inside shoulder narrow grooves 32 disposed between the inside shoulder lug grooves 23 adjacent to each other; outside shoulder lug grooves 26 which stride over a ground contact end T and extend in a tire width direction; and outside shoulder narrow grooves 36 disposed between the outside shoulder lug grooves 26 adjacent to each other. A shoulder land section 45 has a plain region 46 where a groove 5 is not formed over the whole circumference in a tire circumferential direction between the inside shoulder lug grooves 23 and the inside shoulder narrow grooves 32 in the tire width direction and the outside shoulder lug grooves 26 and the outside shoulder narrow grooves 36. When a distance between the outermost main groove 15 and the ground contact end T is a ground contact width W1 of the shoulder land section 45, the plain region 46 has a width W2 in the tire width direction which is within a range of not less than 20% and not more than 80% of the ground contact width W1.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire.

  Pneumatic tires are provided with a groove on the tread surface to drain the water between the tread surface and the road surface in order to ensure driving performance in rainy weather, while the groove on the tread surface is unevenly worn. It becomes the cause of. In particular, since a large load acts on the shoulder region during turning, uneven wear is likely to occur. For this reason, some conventional pneumatic tires attempt to suppress uneven wear in the shoulder region. is there. For example, the pneumatic tire described in Patent Document 1 includes 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 alternately arranging the land portions in a zigzag manner in the circumferential direction of the tire, the load is prevented from concentrating during rotation of the pneumatic tire, thereby suppressing uneven wear.

Japanese Patent No. 5249666

  However, in the shoulder region, when the lug grooves and sipes are alternately arranged in the tire circumferential direction, those extending from the main groove side to the shoulder end side and those extending from the shoulder end side to the main groove side, There is a possibility that the rigidity of the land portion may be reduced due to the narrow interval. The rigidity of the land portion is an important factor for handling stability, and when the rigidity of the land portion is lowered, the maneuverability may be lowered. For this reason, it has been very difficult to suppress uneven wear without reducing the operability.

  This invention is made | formed in view of the above, Comprising: It aims at providing the pneumatic tire which can make stability and uneven wear resistance compatible.

  In order to solve the above-described problems and achieve the object, a pneumatic tire according to the present invention includes a plurality of main grooves formed on a tread surface and extending in a tire circumferential direction, and a tire width direction among the plurality of main grooves. The outermost main groove, which is the outermost main groove located at the outermost side of the outermost main groove, is adjacent to the outermost main groove and adjacent to the outermost main groove, and the shoulder land portion through which the ground contact end passes, and one end of the main groove extending in the tire width direction A plurality of inner shoulder lug grooves connected to the outermost main groove and having the other end terminating in the shoulder land portion, and disposed between the adjacent inner shoulder lug grooves and extending in the tire width direction, at least the tire A plurality of inner shoulder narrow grooves whose outer ends in the width direction terminate in the shoulder land portion, and extend in the tire width direction across the ground contact edge, and at least the inner end portion in the tire width direction is the shoulder land portion A plurality of outer shoulder lug grooves that terminate in the outer shoulder lug grooves and the adjacent outer shoulder lug grooves that extend in the tire width direction across the ground contact edge, and at least an inner end portion in the tire width direction is the shoulder A plurality of outer shoulder narrow grooves that terminate in the land portion, and an inner shoulder lug groove end portion that is an end portion in the tire width direction outer side of the inner shoulder lug groove and an outer end portion in the tire width direction of the inner shoulder narrow groove. The inner shoulder narrow groove end portion is an outer shoulder lug groove end portion that is an inner end portion in the tire width direction of the outer shoulder lug groove and an outer shoulder narrow groove end portion that is an inner end portion in the tire width direction of the outer shoulder narrow groove. The shoulder land portion is located on the inner side in the tire width direction than the portion, and the inner shoulder lug groove in the tire width direction and the Between the side shoulder narrow groove, the outer shoulder lug groove and the outer shoulder narrow groove, there is a plain region that is a region where no groove is formed over the entire circumference in the tire circumferential direction. When the distance between the outer main groove and the ground contact end in the tire width direction is the ground contact width W1 of the shoulder land portion, the plain region has a width W2 in the tire width direction of 20% of the ground contact width W1. It is characterized by being in the range of 80% or less.

  In the pneumatic tire, the plain region is located at a position where a distance WL in the tire width direction from the outermost main groove is in a range of 20% to 40% with respect to the ground contact width W1. It is preferable.

  In the pneumatic tire, a distance L1 in the tire circumferential direction between the outer shoulder lug groove ends of the outer shoulder lug grooves adjacent to each other, and a position in the tire circumferential direction is located between the outer shoulder lug groove end portions. The relationship between the inner shoulder lug groove end portion and the outer shoulder lug groove end portion between 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.

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

  In the pneumatic tire, the outer shoulder narrow groove end of the outer shoulder narrow groove and one outer side of two outer shoulder lug grooves adjacent to the outer shoulder narrow groove in the tire width direction. When the distance in the tire circumferential direction with the shoulder lug groove is L3, and the distance in the tire circumferential direction between the outer shoulder narrow groove end and the other outer shoulder lug groove is L4, the distance L3 and the distance L4 Is within a range of 0.8 ≦ (L3 / L4) ≦ 1.2, and the two inner shoulder lug grooves adjacent to each other in the tire width direction with respect to the inner shoulder narrow groove and the inner shoulder narrow groove. In the inner shoulder narrow groove end of the inner shoulder narrow groove than the inner shoulder lug groove end of the inner shoulder lug groove Is located on the outer side in the tire width direction, the distance in the tire circumferential direction between the inner shoulder lug groove end portion of the inner shoulder lug groove and the inner shoulder narrow groove of one of the two inner shoulder lug grooves is L5, where L6 is the distance in the tire circumferential direction between the inner shoulder lug groove end of the other inner shoulder lug groove and the inner shoulder narrow groove, the distance L5 and the distance L6 are 0.8 ≦ (L5 / L6) ≦ 1.2, and the inner shoulder narrow groove end portion of the inner shoulder narrow groove is located on the inner side in the tire width direction than the inner shoulder lug groove end portion of the inner shoulder lug groove. The inner shoulder lug groove and the inner shoulder lug groove of one of the two inner shoulder lug grooves. The distance in the circumferential direction is L5, the distance in the tire circumferential direction between the inner shoulder narrow groove end and the other inner shoulder lug groove is L6, and the distance L5 and the distance L6 are 0.8 ≦ (L5 / L6) is preferably in the range of ≦ 1.2.

  Further, in the pneumatic tire, an area of a rectangle whose corners are four ends formed from both ends of each of the two outer shoulder lug grooves adjacent to each other is defined as S1, and the four sides constituting the rectangle are Of these, two intersections between the outermost main groove and two extended lines that extend the two sides connecting the ends of the one outer shoulder lug groove toward the outermost main groove, and the two outer sides When the area of a rectangle having the corner portions of the two outer shoulder lug groove end portions 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.

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

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 diagram regarding the relative positional relationship between the length of the lug groove and the narrow groove of the shoulder land portion. FIG. 4 is an explanatory diagram of a region where the outer shoulder lug groove is not provided in the shoulder land portion. FIG. 5 is a modified example of the pneumatic tire according to the embodiment, and is an explanatory diagram in a case where the inner shoulder narrow groove end portion is located on the outer side in the tire width direction than the inner shoulder lug groove end portion. FIG. 6 is a modified example of the pneumatic tire according to the embodiment, and is an explanatory diagram in a case where the inner shoulder narrow groove end portion is located on the outer side in the tire width direction than the inner shoulder lug groove end portion. FIG. 7A is a chart showing the results of a performance test of a pneumatic tire. FIG. 7B 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, and the tire circumferential direction means a direction rotating around the tire rotation axis.

  FIG. 1 is a plan view showing a tread surface of a pneumatic tire according to an embodiment. The pneumatic tire 1 shown in FIG. 1 has a tread portion 2 disposed on the outermost side in the tire radial direction, and the surface of the tread portion 2, that is, a vehicle in which the pneumatic tire 1 is mounted ( A portion that is in 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 groove 5 includes 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 with a groove width narrower than that of the main groove 10 or the lug groove 20. A plurality of each is formed.

  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 across the tire equatorial plane CL. The main groove 10 has a groove width in the range of 3 mm to 15 mm, and a groove depth in the range of 4 mm to 10 mm.

  Of the three main grooves 10, the main groove 10 located on the tire equatorial plane CL is provided as a center main groove 11, located on the outer side in the tire width direction of the center main groove 11 and in the center main groove 11. The two main grooves 10 adjacent to each other are provided as the outermost main grooves 15. That is, of the plurality of main grooves 10, the two main grooves 10 positioned 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 swings in the tire width direction while extending in the tire circumferential direction, that is, the center main groove 11 extends in the tire circumferential direction and is uneven in the tire width direction. Are formed in a zigzag shape. Of the three main grooves 10, the two outermost main grooves 15 are formed as straight grooves extending linearly in the tire circumferential direction.

  In the land portion 40, two center land portions 41 and two shoulder land portions 45 are partitioned by the three main grooves 10. Among these, the center land portion 41 is a land portion 40 partitioned by the center main groove 11 and the outermost main groove 15. The center land portion 41 is located on both sides in the tire width direction of the center main groove 11. Are formed between the center main groove 11 and the outermost main groove 15 on both sides in the tire width direction. Further, the shoulder land portion 45 is located on the outer side of 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 that is defined by the outermost main groove 15 on the inner side in the tire width direction, and is located on the outer side in the tire width direction of the outermost main groove 15. To the end of the tread surface 3 on the outer side in the tire width direction.

  In this case, the ground contact end T is mounted on the flat rim in a vertical direction on the flat plate 1 with the pneumatic tire 1 mounted on the specified rim and with a specified internal pressure, for example, an internal pressure condition of air pressure corresponding to a specified load and a specified load condition. A 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 loaded. That is, the grounding end T is at the maximum position of the grounding width on the grounding surface with the specified internal pressure and the specified load.

  The specified rim refers to “applied rim” defined in JATMA, “Design Rim” defined in TRA, or “Measuring Rim” defined in ETRTO. The specified internal pressure refers to the “maximum air pressure” specified in JATMA, 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 “maximum load capacity” defined in JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined in TRA, or “LOAD CAPACITY” defined in ETRTO.

  The lug groove 20 is connected to the outermost main groove 15 located on the outer side in the tire width direction with respect 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. The inner shoulder lug groove 23 and the outer shoulder lug groove 26 located on the outer side in the tire width direction than the inner shoulder lug groove 23 are provided.

  Among these, the center lug groove 21 has an end on the outer side in the tire width direction connected to the outermost main groove 15, and an end on the inner side in the tire width direction terminates in the center land portion 41. Further, the center lug groove 21 is curved in the direction toward the tire circumferential direction from the end connected to the outermost main groove 15 toward the end in the center land portion 41 in the tire width direction. ing. A plurality of center lug grooves 21 are formed side by side in the tire circumferential direction at positions between the two center main grooves 11 and the outermost main groove 15. Further, the center lug groove 21 connected to one outermost main groove 15 has the same bending direction in the tire circumferential direction, and the center lug groove 21 connected to different outermost main grooves 15. In each other, the bending directions in the tire circumferential direction are opposite to each other. The center lug groove 21 provided in this way has a groove depth in the range of 1 mm or more and 8 mm or less, and ends in the center land portion 41 from the end connected to the outermost main groove 15. The width of the groove becomes narrower toward the end portion on the side where it is running.

  The inner shoulder lug groove 23 has one end connected to the outermost main groove 15, the other end terminating in the shoulder land portion 45, and a plurality of inner shoulder lug grooves 23 formed side by side in the tire circumferential direction. That is, the inner shoulder lug groove 23 located on the outer side in the tire width direction with respect to the outermost main groove 15 has an end on the inner side in the tire width direction connected to the outermost main groove 15 and an end on the outer side in the tire width direction with the shoulder land. It terminates in the part 45. Further, the inner shoulder lug groove 23 is inclined in the tire circumferential direction while heading in the tire width direction from the end side connected to the outermost main groove 15 toward the end side terminating in the shoulder land portion 45. ing. The inner shoulder lug grooves 23 connected to one outermost main groove 15 are all inclined in the tire circumferential direction in the same direction, and the inner shoulder lug grooves 23 connected to different outermost main grooves 15. In each other, the inclination directions in the tire circumferential direction when facing 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 thus provided has a groove width in the range of 1 mm to 5 mm and a groove depth in the range of 1 mm to 8 mm.

  Further, the outer shoulder lug groove 26 extends in the tire width direction across the ground contact edge T, and at least an inner end portion in the tire width direction terminates in the shoulder land portion 45, and a plurality of the outer shoulder lug grooves 26 are arranged in the tire circumferential direction. Is formed. That is, the outer shoulder lug groove 26 is formed across the ground contact edge T by extending in the tire width direction at a position outside the inner shoulder lug groove 23 in the tire width direction. The outer shoulder lug groove 26 is inclined in the tire circumferential direction from the end side on the outer side in the tire width direction toward the end side on the inner side in the tire width direction, and is gently curved. Yes. In the outer shoulder lug grooves 26 disposed on both sides in the tire width direction, the outer shoulder lug grooves 26 disposed on the same direction side in the tire width direction are all inclined in the tire circumferential direction in the same direction. It has become. Further, in the outer shoulder lug grooves 26 disposed on different direction sides in the tire width direction, the inclination to the tire circumferential direction when the tire width direction outer end side is directed to the tire width direction inner end side. The directions are opposite to each other. The outer shoulder lug groove 26 thus provided has a groove width in the range of 1 mm to 8 mm and a groove depth in the range of 1 mm to 8 mm.

  The narrow groove 30 is disposed 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 which is disposed between the 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 where the narrow groove 30 is formed.

  Among the plurality of narrow grooves 30, the center narrow groove 31 is formed to be inclined in the tire width direction while extending in the tire width direction, and both ends terminate in the center land portion 41. Further, the center narrow groove 31 has a position in the tire width direction near the end 22 on the inner side in the tire width direction of the center lug groove 21. 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 is not connected to the center lug groove 21. It is formed between adjacent center lug grooves 21. A plurality of the center narrow grooves 31 are formed between the adjacent center lug grooves 21 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 center land portion 41 has the groove 5 formed over the entire circumference in the tire circumferential direction. It has a plain area 42 that is not present. That is, the region in the tire width direction from the end 22 on the inner side in the tire width direction of the center lug groove 21 to the top portion 12 protruding toward the center lug groove 21 in the center main groove 11 formed in a zigzag shape is the center land. This is a plain area 42 of the portion 41. In other words, the end portion 43 on the inner side in the tire width direction in the plain region 42 of the center land portion 41 is the position in the tire width direction of the top portion 12 of the portion projecting toward the plain region 42 in the center main groove 11. The end portion 43 on the outer side in the tire width direction in the plain region 42 is a position in the tire width direction of the end portion 22 on the inner side in the tire width direction of the center lug groove 21.

  The end 22 of the center lug groove 21 is formed in 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 plain region 42 is the position in the tire width direction of the innermost portion in the tire width direction at the end portion 22 of the center lug groove 21. .

  Further, among the plurality of narrow grooves 30, the inner shoulder narrow groove 32 is inclined in the same direction as the direction in which the inner shoulder lug groove 23 is inclined in the tire circumferential direction while extending in the tire width direction. Both ends terminate in the shoulder land portion 45. The inner shoulder narrow groove 32 may be connected to the outermost main groove 15 at the inner end in the tire width direction, and at least the outer end in the tire width direction may be terminated within the shoulder land portion 45. That's fine.

  Of 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 direction in which the outer shoulder lug groove 26 is inclined in the tire circumferential direction. Both ends terminate in the shoulder land portion 45. The outer shoulder narrow groove 36 may have an end portion on the inner side in the tire width direction connected to a groove formed on the outer side in the tire width direction with respect to the ground contact end T, and at least an end portion on the inner side in the tire width direction. What is necessary is just to terminate in the shoulder land part 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 disposed on the outer side in the tire width direction from the outermost main groove 15 are similarly outer shoulders disposed on the outer side in the tire width direction from the outermost main groove 15. All parts are located on the inner side in the tire width direction with respect to the lug groove 26 and the outer shoulder narrow groove 36. That is, the inner shoulder lug groove end portion 24 which is the outer end portion in the tire width direction of the inner shoulder lug groove 23 and the inner shoulder narrow groove end portion 33 which is the end portion in the tire width direction outer side of the inner shoulder narrow groove 32 are the outer shoulder. The outer shoulder lug groove end portion 27 which is an end portion in the tire width direction of the lug groove 26 and the outer shoulder narrow groove end portion 37 which is an end portion in the tire width direction of the outer shoulder narrow groove 36 are located on the inner side 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 and the outer shoulder lug groove 26 and the outer shoulder narrow groove 36 in the tire width direction. The plane region 46 is a region where 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 on the outer side in the tire width direction, the outer shoulder lug groove end portion 27 and the outer shoulder narrow groove end portion 37 A region in the tire width direction up to a position in the tire width direction on the inner side in the tire width direction is a plain region 46 of the shoulder land portion 45.

  In the present embodiment, the inner shoulder narrow groove end portion 33 is positioned on the outer side in the tire width direction than the inner shoulder lug groove end portion 24, and the outer shoulder lug groove end portion 27 is more on the tire than the outer shoulder narrow groove end portion 37. Since it is located on the inner side in the width direction, the region in the tire width direction from the position in the tire width direction of the inner shoulder narrow groove end portion 33 to the position in the tire width direction of the outer shoulder lug groove end portion 27 becomes the plain region 46. ing. In other words, the end 47 on the inner side in the tire width direction in the plain region 46 of the shoulder land portion 45 is the position in the tire width direction of the inner shoulder narrow groove end 33, and the end on the outer side in the tire width direction in the plain region 46. 47 is the position of the outer shoulder lug groove end portion 27 in the tire width direction.

  In addition, the outer side shoulder lug groove edge part 27 is formed over the predetermined range by being formed in circular arc shape etc. For this reason, the end portion 47 on the outer side in the tire width direction in the plain region 46 is, strictly speaking, the 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 plain region 46 formed in this way has the width of the plain region 46 in the tire width direction when the distance in the tire width direction between the outermost main groove 15 and the contact end T is the contact width W1 of the shoulder land portion 45. W2 is in the range of 20% to 80% with respect to the grounding width W1. That is, the relationship between the width W2 of the plane region 46 and the ground width W1 of the plane region 46 is in the range of 0.2 ≦ (W2 / W1) ≦ 0.8.

  The width W2 of the plain 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 in the range of 0.4 ≦ (W2 / W1) ≦ 0.6.

  The plain 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% to 40% with respect to the ground contact width W1. That is, in the plain region 46, the relationship between the distance WL from the outermost main groove 15 of the end 47 in the tire width direction in the plain 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 such 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 in the tire circumferential direction between the outer shoulder lug groove end portions 27 of the adjacent outer shoulder lug grooves 26 and a position in the tire circumferential direction. A distance L2 in the tire circumferential direction 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 one of the outer shoulder lug groove ends 27, and Is in the range of 0.2 ≦ (L2 / L1) ≦ 0.8.

  That is, when paying attention to one outer shoulder lug groove 26, the distance L <b> 1 is equal to the outer shoulder lug groove end portion 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 such that the position in the tire circumferential direction is the position between the outer shoulder lug groove ends 27 between the outer shoulder lug groove ends 27 and the outer shoulder lug groove end portion 27 of the outer shoulder lug groove 26 of interest. And 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. Within the following range.

  A 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 a distance L1 between the outer shoulder lug groove end portions 27 in the tire circumferential direction. It is preferable to be within the range. That is, the relationship between the distance L1 and the distance L2 is preferably in the range of 0.4 ≦ (L2 / L1) ≦ 0.6.

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

  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 from the ground contact end T in the same manner as the position of the end portion 47 of the plain region 46 of the shoulder land portion 45. It is a distance W5 in the tire width direction to the innermost portion in the tire width direction in the outer shoulder lug groove end portion 27.

  Further, the inner shoulder lug groove 23 is longer in the tire width direction than the inner shoulder thin 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 24. The relationship with the distance W6 is in the range of 0.2 ≦ (W4 / W6) ≦ 0.8. That is, the length W4 in the tire width direction of the inner shoulder narrow groove 32 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 in the range of 20% to 80% 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 outermost main, similarly 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 a distance W6 in the tire width direction from the groove 15 to the outermost portion in the tire width direction at the inner shoulder lug groove end portion 24.

  The outer shoulder lug groove 26 and the outer shoulder narrow groove 36 are respectively in the tire circumferential direction of the two outer shoulder lug grooves 26 and the outer shoulder narrow groove 36 that are located on both sides of the outer shoulder narrow groove 36 in the tire circumferential direction. The distances are within a predetermined range. Specifically, an outer shoulder narrow groove end portion 37 of the outer shoulder narrow groove 36 and one outer shoulder lug groove 26 of two outer shoulder lug grooves 26 adjacent to the outer shoulder narrow groove 36 in the tire width direction; When the distance in the tire circumferential direction is L3 and the distance in the tire circumferential direction between the outer shoulder narrow groove end portion 37 and the other outer shoulder lug groove 26 is L4, the distance L3 and the distance L4 are 0.8 ≦ It is in 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 portions at the edge portion on the outer shoulder narrow groove end portion 37 side in the opening of the outer shoulder lug groove 26. This is the distance in the tire circumferential direction between the portion that is the same as the position in the tire width direction 37 and the outer shoulder narrow groove end portion 37. That is, the distance L3 in the tire circumferential direction between the outer shoulder narrow groove end portion 37 and the one outer shoulder lug groove 26 is equal to the distance L4 in the tire circumferential direction between the outer shoulder narrow groove end portion 37 and the other outer shoulder lug groove 26. Therefore, it is in the range of 80% or more and 120% or less. In other words, the outer shoulder narrow groove 36 is disposed near the center position in the tire circumferential direction between the adjacent outer shoulder lug grooves 26.

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

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

  FIG. 4 is an explanatory diagram of a region where the outer shoulder lug groove is not provided in the shoulder land portion. The outer shoulder lug groove 26 is provided such that a region where the outer shoulder lug groove 26 is not formed in the shoulder land portion 45 is within a predetermined range with respect to a region where the outer shoulder lug groove 26 is formed. . Specifically, the area of the outer rectangle 51, which is the rectangle 50 having the corners 52 at the four ends of the two outer shoulder lug grooves 26 adjacent to each other, is S1, and the outer rectangle 51 is formed 4 Two intersection points 66 of the outermost main groove 15 and the extension line 65 extending from the two sides 53 connecting the ends of one outer shoulder lug groove 26 to the outermost main groove 15. And the area S1 and the area S2 when the area of the inner rectangle 61, which is the rectangle 50 having the corner portions 62 as the two outer shoulder lug groove end portions 27 of the two outer shoulder lug grooves 26, is S2, The relationship is within the range of 1 ≦ (S2 / S1) ≦ 1.3.

  Among these, the corner 52 of the outer rectangle 51 is P1 at the midpoint of the groove opening at the outer end in the tire width direction of one outer shoulder lug groove 26, and the outer shoulder lug groove end portion of the outer shoulder lug groove 26. 27, P2 is the midpoint of the groove opening portion, and P1 ′ is the midpoint of the groove opening portion at the outer end in the tire width direction of the other outer shoulder lug groove 26. The center points 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 is a rectangle 50 in which the midpoints P1, P2, P1 ′, P2 ′ are connected by the four sides 53, and the positions of the midpoints P1, P2, P1 ′, P2 ′ are the corners 52. ing.

  Further, the corner portion 62 of the inner rectangle 61 includes an extension line 65 that extends a side 53 connecting the midpoint P1 and the midpoint P2 of the outer rectangle 51 toward the outermost main groove 15 and an opening portion of the outermost main groove 15. An intersection 66 with the outer portion in the tire width direction at point P3 is defined as a point P3, an extension line 65 extending toward the outermost main groove 15 along a side 53 connecting the midpoint P1 ′ and the midpoint P2 ′ of the outer rectangle 51, When the intersection 66 with the outer portion in the tire width direction in the opening of the outer main groove 15 is a point P3 ′, there are a middle point P2, a middle point P2 ′, a point P3, and a point P3 ′. In other words, the inner rectangle 61 connects the middle point P2, the middle point P2 ′, the point P3, and the point P3 ′ with the four sides 63, and the positions of the middle point P2, the middle point P2 ′, the point P3, and the point P3 ′ are expressed as corners. A rectangle 50 is formed as a portion 62. The outer shoulder lug groove 26 is formed such that the area S2 of the inner rectangle 61 defined as described above is within a range of 100% to 130% with respect to the area S1 of the outer rectangle 51.

  FIG. 5 and FIG. 6 are modified examples of the pneumatic tire according to the embodiment, and are explanatory diagrams when the inner shoulder narrow groove end is positioned on the outer side in the tire width direction than the inner shoulder lug groove end. In the embodiment described above, the inner shoulder narrow groove end portion 33 is positioned on the outer side in the tire width direction than the inner shoulder lug groove end portion 24, but on the contrary, on the inner shoulder narrow groove end portion 33, The shoulder lug groove end 24 may be located on the outer side in the tire width direction. That is, the inner shoulder narrow groove end portion 33 is connected to the inner shoulder lug by disposing the inner shoulder narrow groove 32 at a position where the inner shoulder narrow groove 32 inner end in the tire width direction is connected to the outermost main groove 15. It may be located on the inner side in the tire width direction than the groove end portion 24. In this case, as shown in FIG. 5, the relative positional relationship between the inner shoulder narrow groove 32 and the two inner shoulder lug grooves 23 adjacent to the inner shoulder narrow groove 32 in the tire width direction is The distance between the lug groove end portion 24 and one inner shoulder lug groove 23 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 is the tire. The distance in the circumferential direction is L6, and the distance L5 and the distance L6 are preferably in the range of 0.8 ≦ (L5 / L6) ≦ 1.2. In other words, the distance L5 in the tire circumferential direction between one inner shoulder lug groove 23 and the inner shoulder narrow groove end 33 is equal to the distance L6 in the tire circumferential direction between the other inner shoulder lug groove 23 and the inner shoulder narrow groove end 33. On the other hand, it is preferably within 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 end of the inner shoulder lug groove 23 in the inner shoulder narrow groove 32 and the two inner shoulder lug grooves 23 adjacent to the inner shoulder narrow groove 32 in the tire width direction. When the inner shoulder narrow groove end portion 33 of the inner shoulder narrow groove 32 is positioned on the outer side in the tire width direction than the portion 24, the tire shoulder circumferential direction between one inner shoulder lug groove end portion 24 and the inner shoulder narrow groove 32 is The distance is L5, and the distance in the tire circumferential direction between the other inner shoulder lug groove end 24 and the inner shoulder narrow groove 32 is L6. Further, when the inner shoulder narrow groove end portion 33 of the inner shoulder narrow groove 32 is located on the inner side in the tire width direction than the inner shoulder lug groove end portion 24 of the inner shoulder lug groove 23, The distance between the inner shoulder lug groove 23 in 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 shoulder lug groove 23 are in any relation in the positional relationship in the tire width direction between the inner shoulder lug groove end 24 and the inner shoulder narrow groove end 33. The shoulder narrow groove 32 is preferably formed such that the distance L5 and the distance L6 are within a range of 0.8 ≦ (L5 / L6) ≦ 1.2.

  When the inner shoulder lug groove end portion 24 is positioned on the outer side in the tire width direction than the inner shoulder narrow groove end portion 33, the plain region 46 of the shoulder land portion 45 has an outer shoulder lug as shown in FIG. A region in the tire width direction from a position in the tire width direction of the groove end portion 27 to a position in the tire width direction of the inner shoulder lug groove end portion 24 is a plain region 46. That is, in this case, the outer edge 47 in the tire width direction in the plain region 46 of the shoulder land portion 45 is the position in the tire width direction of the outer shoulder lug groove end portion 27, and the end in the tire width direction in the plain region 46. The portion 47 is a position in the tire width direction of the inner shoulder lug groove end portion 24.

  In addition, since the inner shoulder lug groove end portion 24 is formed over a predetermined range by being formed in an arc shape or the like, the end portion 47 on the inner side in the tire width direction in the plain region 46 is strictly, In the inner shoulder lug groove end portion 24, the outermost portion in the tire width direction is the position in the tire width direction.

  Thus, even when the position of the inner shoulder lug groove end portion 24 in the tire width direction is the position of the end portion 47 on the inner side of the plain region 46 in the tire width direction, the width W2 of the plain region 46 in the tire width direction is It is in the range of 20% to 80% with respect to the ground contact width W1. Also in this case, in the plain region 46, the relationship between the distance WL from the outermost main groove 15 of the end 47 in the tire width direction and the ground contact width W1 of the shoulder land portion 45 is 0.2 ≦ ( WL / W1) ≦ 0.4.

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

  In the embodiment described above, one outer shoulder narrow groove 36 is provided between the adjacent outer shoulder lug grooves 26, but the outer shoulder narrow groove 36 is formed between the adjacent outer shoulder lug grooves 26. A plurality may be provided between them. In this case, the relationship between the distance W 3 from the ground contact end T to the outer shoulder narrow groove end portion 37 and the distance W 5 from the ground contact end T to the outer shoulder lug groove end portion 27 is the outer shoulder 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 on the innermost side 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 narrow groove end 37 and the outer shoulder lug groove 26 are the outer shoulders of the plurality of outer shoulder narrow grooves 36 where the outer shoulder narrow groove end 37 is located at the innermost side in the tire width direction. The distances L3 and L4 between the outer shoulder narrow groove end portion 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 narrow 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 narrow groove 32 in the tire width direction and the distance W6 from the outermost main groove 15 to the inner shoulder lug groove end portion 24 is the tire among the plurality of inner shoulder narrow grooves 32. The length W4 in the tire width direction of the inner shoulder narrow groove 32 having the longest length in the width direction may be within a range of 0.2 ≦ (W4 / W6) ≦ 0.8 with respect to the distance W6. Similarly, when the inner shoulder narrow groove ends 33 of the plurality of inner shoulder narrow grooves 32 are all located on the inner side in the tire width direction from the inner shoulder lug groove end 24, the inner shoulder narrow groove ends 33 and the inner shoulder lug grooves are similarly formed. The distances L5 and L6 between the inner shoulder narrow groove end 33 and the inner shoulder lug of the inner shoulder narrow groove 32 of which the inner shoulder narrow groove end portion 33 is located on the outermost side in the tire width direction among the plurality of inner shoulder narrow grooves 32. The distances L5 and L6 with 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 a vehicle and 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 the vehicle travels 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 provide a space between the tread surface 3 and the road surface. Travel while draining the water. 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.

  Various grooves 5 are formed on the tread surface 3 of the pneumatic tire 1 in order to ensure drainage performance on such a wet road surface. The portion in the vicinity of the portion where is formed has low rigidity due to these grooves 5. For this reason, when the land portion 40 comes into contact with the road surface during traveling of the vehicle, a portion of the land portion 40 near the groove 5 is easily deformed by a load received from the road surface. In particular, the shoulder land portion 45 is easily subjected to a large load when the vehicle turns.

  On the other hand, the shoulder land portion 45 is provided with a plain region 46 that is a region where 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 difficult to deform even when a load acts on the shoulder land portion 45. 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 in which the rigidity is ensured can receive the load without being greatly deformed, and the rigidity near the ground contact T can be reduced. Since it can be ensured, operability can be ensured.

  In addition, since the lug groove 20 and the narrow groove 30 are formed on both sides of the plain region 46 in the tire width direction, the plain region 46 is secured while ensuring the rigidity of the shoulder land portion 45 for ensuring maneuverability. On both sides in the tire width direction, it is possible to give an appropriate elasticity. Thereby, it can suppress that a big load acts on a part of tread surface 3, and since local abrasion can be suppressed, uneven wear resistance can be ensured.

  Further, since the width W2 in the tire width direction of the plain region 46 is in the range of 20% to 80% of the ground contact width W1 of the shoulder land portion 45, uneven wear is improved while improving the rigidity of the shoulder land portion 45. Can be suppressed. That is, when the width W2 of the plain 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 plain 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 fear. On the other hand, when the width W2 of the plain 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 do. As a result, both maneuverability and uneven wear resistance can be achieved.

  The plain 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 more reliably suppressing uneven wear. That is, when the distance WL between the outermost main groove 15 and the plain region 46 is less than 20% with respect to the ground contact width W1 of the shoulder land portion 45, the plain region 46 is too close to the outermost main groove 15 and the tire Since it is located too much on the inner side 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 end T having a high ground pressure. Therefore, the rigidity in the vicinity of 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 plain region 46 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, uneven wear is appropriately prevented. The rigidity of the shoulder land portion 45 can be effectively improved while suppressing. As a result, it is possible to more reliably achieve both maneuverability and uneven wear resistance.

  The relationship between the distance L1 in the tire circumferential direction between the outer shoulder lug groove end portions 27 adjacent in the tire circumferential direction and the distance L2 in the tire circumferential direction between the outer shoulder lug groove end portion 27 and the inner shoulder lug groove end portion 24 is as follows. Since it is in the range of 0.2 ≦ (L2 / L1) ≦ 0.8, it is possible to suppress the occurrence of a portion with 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 short. The rigidity between the inner shoulder lug groove 23 and the outer shoulder lug groove 26 is lowered, and it may be difficult to effectively improve the maneuverability. In this case, since the difference in rigidity between the plain region 46 and the position away from the inner shoulder lug groove 23 and the outer shoulder lug groove 26 is increased, the effect of improving uneven wear resistance may be reduced. On the other hand, when the relationship between the distance L1 and the distance L2 is in 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 short. Since it becomes possible to suppress becoming too much, it is possible to suppress the occurrence of a portion having low rigidity in the plane region 46, and it is possible to suppress the rigidity difference from becoming too large. As a result, it is possible to more reliably achieve both stability and uneven wear resistance.

  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 plain region 46 and the ground contact end T can be made moderate. 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, and therefore, between the plain region 46 and the ground contact edge T in the shoulder land portion 45. It may be difficult to moderately moderate the rigidity of the portion, and it may be difficult to suppress uneven wear. 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 plain region 46 and the ground contact end T is small. It becomes low and it may become difficult to improve the rigidity of the shoulder land part 45 effectively. On the other hand, when the relationship between the distance W3 and the distance W5 is in the range of 0.2 ≦ (W3 / W5) ≦ 0.8, the length of the outer shoulder narrow groove 36 relative to the outer shoulder lug groove 26 is Since the length can be set appropriately, the rigidity of the portion of the shoulder land portion 45 between the plain region 46 and the ground contact end T can be appropriately sized, and while suppressing uneven wear, the shoulder land portion The rigidity of 45 can be ensured. As a result, it is possible to more reliably achieve both stability and uneven wear resistance.

  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 plain region 46 and the outermost main groove 15 in the shoulder land portion 45 can be made moderate. 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, and therefore the plain region 46 and the outermost main groove 15 in the shoulder land portion 45 are It may be difficult to moderately moderate the rigidity of the portion between them, and it may be difficult to suppress uneven wear. 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 plain region 46 and the outermost main groove 15 There is a possibility that the rigidity is lowered and it is 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 in 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 Therefore, the rigidity of the portion between the plain region 46 and the outermost main groove 15 in the shoulder land portion 45 can be appropriately sized, and while suppressing uneven wear, The rigidity of the shoulder land portion 45 can be ensured. As a result, it is possible to more reliably achieve both stability and uneven wear resistance.

  Further, a distance L3 in the tire circumferential direction between one outer shoulder lug groove 26 and the outer shoulder narrow groove end portion 37 of the two outer shoulder lug grooves 26 adjacent to the outer shoulder narrow groove 36 in the tire width direction, Since the distance L4 in the tire circumferential direction between the other outer shoulder lug groove 26 and the outer shoulder narrow groove end portion 37 is within the range of 0.8 ≦ (L3 / L4) ≦ 1.2, the plane in the shoulder land portion 45 It is possible to suppress a difference in rigidity from occurring in the region between the region 46 and the ground contact end T. In other words, when (L3 / L4) <0.8 or (L3 / L4)> 1.2, rigidity is obtained in the region between the plain region 46 and the ground contact end T in the shoulder land portion 45. Differences may occur and rigidity may become too low or uneven wear may occur. 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, the distance between the plane region 46 and the ground contact edge T in the shoulder land portion 45 is as follows. It is possible to suppress the occurrence of a rigidity difference in the region, and it is possible to suppress uneven wear while securing the rigidity of the shoulder land portion 45. As a result, it is possible to more reliably achieve both stability and uneven wear resistance.

  Further, in the inner shoulder narrow groove 32 and the two inner shoulder lug grooves 23 adjacent to each other in the tire width direction with respect to the inner shoulder narrow groove 32, the tire of one inner shoulder lug groove end portion 24 and the inner shoulder narrow groove 32. The distance L5 in the circumferential direction and the distance in the tire circumferential direction between the other inner shoulder lug groove end 24 and the inner shoulder narrow groove 32 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 in the tire circumferential direction between the inner shoulder narrow groove end portion 33 and the other inner shoulder lug groove 23 are in 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 plain region 46 and the outermost main groove 15 in the shoulder land portion 45. Door can be. That is, when (L5 / L6) <0.8 or (L5 / L6)> 1.2, the region between the plain region 46 and the outermost main groove 15 in the shoulder land portion 45. May cause a difference in rigidity, which may result in excessively low rigidity or uneven wear. 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 plain 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, it is possible to more reliably achieve both stability and uneven wear resistance.

  Further, the area S1 of the outer rectangle 51 having the corner portions 52 at both ends of the two outer shoulder lug grooves 26 adjacent to each other, 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 area S2 of the inner rectangle 61 that is the corner 62 between the intersection 66 with the outermost main groove 15 and the outer shoulder lug groove end portion 27 is within the range of 1 ≦ (S2 / S1) ≦ 1.3. The rigidity in the case where the plain region 46 is provided in the shoulder land portion 45 can be appropriately set. In other words, when (S2 / S1) <1, the outer shoulder lug groove 26 is too long in the tire width direction inner side, making it difficult to effectively secure the rigidity of the shoulder land portion 45. It may be difficult to ensure safety. Also, when (S2 / S1)> 1.3, the outer shoulder lug groove 26 is too short, so when the plain region 46 is provided in the shoulder land portion 45, the rigidity of the shoulder land portion 45 becomes too high, It may be difficult to suppress uneven wear. On the other hand, when the relationship between the area S1 and the area S2 is in 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 in the shoulder land portion 45 can be set to an appropriate level, and the rigidity of the shoulder land portion 45 can be ensured while suppressing uneven wear. As a result, it is possible to more reliably achieve both stability and uneven wear resistance.

  Further, the center land portion 41 is also provided with a plain region 42 which is a region where the grooves 5 are not formed over the entire circumference in the tire circumferential direction. Is high. For this reason, even when a large load is applied to the center land portion 41, the plain region 42 is not easily deformed greatly, so that the center land portion 41 can receive a load without being greatly deformed. Thereby, the rigidity near the center in the tire width direction in the ground contact region of the pneumatic tire 1 can be secured, and the maneuverability can be secured. Further, since the center main groove 11, the center lug groove 21, and the center narrow groove 31 are formed on both sides in the tire width direction of the plain region 42, the rigidity of the center land portion 41 for ensuring the maneuverability is While ensuring, moderate elasticity can be given to both sides of the plain region 42 in the tire width direction, and uneven wear can be suppressed. As a result, it is possible to more reliably achieve both stability and uneven wear resistance.

〔Example〕
7A and 7B are tables showing the results of performance tests of pneumatic tires. Hereinafter, the performance evaluation test performed on the pneumatic tire 1 according to the related art and the pneumatic tire 1 according to the present invention will be described. In the performance evaluation test, tests were conducted on the handling and uneven wear resistance.

  In the performance evaluation test, a pneumatic tire 1 with a tire size specified by JATMA of 145 / 80R12 80 / 78N size is assembled to a rim wheel of a 12 × 4.0B size JATMA standard rim and the air pressure is adjusted to 260 kPa. The test was carried out by mounting a light commercial vehicle as a test vehicle on the test vehicle. The evaluation method of each test item was performed by driving the vehicle equipped with the pneumatic tire 1 for performing the evaluation test, and performing sensory evaluation with the paneler. The operability is displayed with a score of 100 as a conventional example, which will be described later, and the greater the value, the better the operability. The uneven wear resistance was evaluated by measuring the wear amount of heel & toe wear in the shoulder land portion 45 after traveling 10,000 km and indexing the reciprocal of the measured value. The uneven wear resistance is represented by an index with a conventional example described later as 100, and the larger the value, the better the uneven wear resistance.

  The evaluation test is a comparison with the conventional pneumatic tire 1 which is an example of the conventional pneumatic tire 1, the examples 1 to 14 which are the pneumatic tire 1 according to the present invention, and the pneumatic tire 1 according to the present invention. It performed about 17 types of pneumatic tires 1 of the comparative examples 1 and 2 which are the pneumatic tires 1 to perform. Among these pneumatic tires 1, the conventional pneumatic tire 1 has no plain region 46 in the shoulder land portion 45. In the pneumatic tires 1 of the comparative examples 1 and 2, the plain region 46 is provided in the shoulder land portion 45, but the ratio of the width W2 of the plain region 46 to the ground contact width W1 of the shoulder land portion 45 is 0. It is outside 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 region 46 is provided in the shoulder land portion 45, and the plain region 46 with respect to the ground contact width W1 of the shoulder land portion 45 is provided. The ratio of the width W2 is in the range of 0.2 ≦ (W2 / W1) ≦ 0.8. Moreover, the pneumatic tire 1 which concerns on Examples 1-14 differs in the relative length and space | interval of the inner side shoulder lug groove 23, the outer side shoulder lug groove 26, the inner side shoulder narrow groove 32, and the outer side shoulder narrow groove 36, respectively. Yes.

  As a result of performing an evaluation test using these pneumatic tires 1, as shown in FIGS. 7A and 7B, the pneumatic tires 1 of Examples 1 to 14 are compared with the conventional examples and the comparative examples 1 and 2. It has been found that both the maneuverability and the resistance to uneven wear can be improved. That is, the pneumatic tire 1 according to Examples 1 to 14 can achieve both stability and uneven wear resistance.

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

Claims (6)

A plurality of main grooves formed in the tread surface and extending in the tire circumferential direction;
A shoulder land portion that is located on the outer side in the tire width direction of the outermost main groove that is the outermost main groove in the tire width direction among the plurality of main grooves, is adjacent to the outermost main groove, and passes through the ground contact end When,
A plurality of inner shoulder lug grooves extending in the tire width direction and having one end connected to the outermost main groove and the other end terminating in the shoulder land portion,
A plurality of inner shoulder narrow grooves disposed between the inner shoulder lug grooves adjacent to each other and extending in the tire width direction, and at least an end portion on the outer side in the tire width direction terminates in the shoulder land portion;
A plurality of outer shoulder lug grooves extending in the tire width direction across the ground contact edge, and at least an inner end portion in the tire width direction terminating in the shoulder land portion,
A plurality of outer shoulder narrow grooves that are disposed between adjacent outer shoulder lug grooves and extend in the tire width direction across the ground contact end, and at least an inner end portion in the tire width direction terminates in the shoulder land portion. When,
With
The inner shoulder lug groove end that is the outer end of the inner shoulder lug groove in the tire width direction and the inner shoulder narrow groove end that is the outer end of the inner shoulder narrow groove in the tire width direction are the outer shoulder lug groove The outer shoulder lug groove end that is the end in the tire width direction and the outer shoulder narrow groove end that is the end in the tire width direction of the outer shoulder narrow groove are located on the inner side in the tire width direction,
The shoulder land portion has a groove 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 that is not formed,
When the distance between the outermost main groove and the ground contact edge in the tire width direction is the ground contact width W1 of the shoulder land portion, the plain region has a width W2 in the tire width direction with respect to the ground contact width W1. A pneumatic tire characterized by being in the range of 20% to 80%.   The said plane area | region is located in the position where the distance WL in the tire width direction from the said outermost main groove exists in the range of 20% or more and 40% or less with respect to the said contact width W1. Pneumatic tire. A distance L1 in the tire circumferential direction between the outer shoulder lug groove ends of the outer shoulder lug grooves adjacent to each other;
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 between the outer shoulder lug groove end portions in the tire circumferential direction. The relationship with the distance L2 at
The pneumatic tire according to claim 1, wherein the pneumatic tire is within a range of 0.2 ≦ (L2 / L1) ≦ 0.8. A distance W3 in the tire width direction from the ground contact end to the outer shoulder narrow groove end;
A distance W5 in the tire width direction from the ground contact edge to the outer shoulder lug groove edge; and
Is within the range of 0.2 ≦ (W3 / W5) ≦ 0.8,
A length W4 of the inner shoulder narrow groove in the tire width direction;
Distance W6 in the tire width direction from the outermost main groove to the inner shoulder lug groove end,
The pneumatic tire according to any one of claims 1 to 3, wherein the relationship is within a range of 0.2 ≦ (W4 / W6) ≦ 0.8. The tire circumferential direction of the outer shoulder narrow groove end 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 in the tire circumferential direction between the outer shoulder narrow groove end portion and the other outer shoulder lug groove is L4, the distance L3 and the distance L4 are 0.8 ≦ (L3 / L4) ≦ 1.2,
In the two inner shoulder lug grooves adjacent to the inner shoulder narrow groove and the inner shoulder narrow groove in the tire width direction,
When the inner shoulder narrow groove end portion of the inner shoulder narrow groove is located on the outer side in the tire width direction than the inner shoulder lug groove end portion of the inner shoulder lug groove, of the two inner shoulder lug grooves. The distance in the tire circumferential direction between the inner shoulder lug groove end of one inner shoulder lug groove and the inner shoulder narrow groove is L5, and the inner shoulder lug groove end of the other inner shoulder lug groove and the inner shoulder thin groove The distance in the tire circumferential direction with respect to the groove is L6, and 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 portion of the inner shoulder narrow groove is located on the inner side in the tire width direction than the inner shoulder lug groove end portion of the inner shoulder lug groove, the inner shoulder lug groove end portion and the two The distance in the tire circumferential direction between one of the inner shoulder lug grooves and the inner shoulder lug groove in the tire circumferential direction is L5, and the distance in the tire circumferential direction between the inner shoulder narrow groove end and the other inner shoulder lug groove is L6, The pneumatic tire according to any one of claims 1 to 4, wherein the distance L5 and the distance L6 are within a range of 0.8 ≦ (L5 / L6) ≦ 1.2. The area of a rectangle whose corners are the four ends of the two outer shoulder lug grooves adjacent to each other is S1,
Of the four sides constituting the rectangle, an extension line extending the two sides connecting the ends of the one outer shoulder lug groove to the outermost main groove and the outermost main groove When the area of a rectangle having two intersections and two outer shoulder lug groove end portions of the two outer shoulder lug grooves as corners is S2,
6. The pneumatic tire according to claim 1, wherein the area S <b> 1 and the area S <b> 2 are in a relationship of 1 ≦ (S <b> 2 / S <b> 1) ≦ 1.3.

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