JP6146490B1 - Pneumatic tire - Google Patents

Abstract

A pneumatic tire capable of improving wet performance and wear resistance performance is provided. A pneumatic tire having a tread portion includes a circumferential main groove provided in the tread portion so as to extend in a tire circumferential direction between a tire center line and a tire ground contact end, and a circumferential main groove. A center land portion provided on the tire center line side, a shoulder land portion provided on the tire ground contact end side with respect to the circumferential main groove, a lug groove provided so as to penetrate the circumferential main groove, and a tire width of the lug groove A first sipe connected to an outer end portion on the outer side in the direction and formed on the shoulder land portion. An inner end portion of the lug groove is disposed in the center land portion outside the tire center line in the tire width direction, and an outer end portion of the lug groove is disposed in the shoulder land portion on the tire width direction inner side than the tire ground contact end. The outer end portion on the outer side in the tire width direction of the first sipe is disposed on the shoulder land portion on the outer side in the tire width direction with respect to the tire ground contact end. [Selection] Figure 5

Description

  The present invention relates to a pneumatic tire.

  For the purpose of achieving both wet performance and wear resistance performance of a pneumatic tire, for example, a pneumatic tire having a tread pattern as disclosed in Patent Document 1 has been proposed.

Japanese Patent No. 5443923

  There is a demand for an improved tread pattern that can achieve both wet performance and wear resistance performance at a higher level.

  An object of an aspect of the present invention is to provide a pneumatic tire capable of improving wet performance and wear resistance performance.

  According to an aspect of the present invention, a pneumatic tire having a tread portion in which a tire center line passing through the center in the tire width direction and a tire ground contact end is defined, between the tire center line and the tire ground contact end A circumferential main groove provided in the tread portion so as to extend in the tire circumferential direction, a center land portion defined by the circumferential main groove, and provided on the tire center line side from the circumferential main groove; A shoulder land portion defined by the circumferential main groove and provided closer to the tire ground contact end than the circumferential main groove, a lug groove provided so as to penetrate the circumferential main groove, and a tire of the lug groove A first sipe that is connected to an outer end portion on the outer side in the width direction and is formed on the shoulder land portion, and an inner end portion of the lug groove is the center on the outer side in the tire width direction with respect to the tire center line. The outer end of the lug groove is disposed on the shoulder land portion on the inner side in the tire width direction than the tire ground contact end, and the outer end portion on the outer side in the tire width direction of the first sipe is the tire. A pneumatic tire is provided that is disposed on the shoulder land portion on the outer side in the tire width direction from the ground contact end.

  According to the aspect of the present invention, the lug groove is provided so as to penetrate the circumferential main groove that divides the center land portion and the shoulder land portion, and the first sipe connected to the outer end portion of the lug groove is the shoulder land. Since it is provided in the part, wet performance and wear resistance performance can be improved. If the first sipe of the shoulder land portion is replaced with a lug groove, the outer end portion of the lug groove is arranged on the outer side in the tire width direction than the tire ground contact end, but the wet performance is improved, but the tread rigidity is reduced. As a result, the wear resistance deteriorates. Moreover, when the lug groove of the shoulder land portion is replaced with the first sipe, the tread rigidity is increased, so that the wear resistance performance is improved, but the wet performance is deteriorated. By connecting the first sipe to the outer end portion of the lug groove penetrating the circumferential main groove, it is possible to achieve both wet performance and wear resistance performance. According to the aspect of the present invention, the first sipe extends to the outside in the tire width direction from the tire ground contact end. When the outer end portion of the first sipe is disposed on the inner side in the tire width direction than the tire ground contact end, it is difficult to obtain sufficient wet performance. A sufficient wet performance can be obtained by disposing the outer end portion of the first sipe on the outer side in the tire width direction with respect to the tire ground contact end.

  In addition, in the aspect of this invention, that a lug groove penetrates the circumferential main groove means that the approximate center of a single linear or arcuate lug groove is arranged in the circumferential main groove.

  In an aspect of the present invention, the lug groove includes a second sipe that is connected to the inner end portion in the tire width direction inside of the lug groove and is formed in the center land portion, and the inner end portion in the tire width direction of the second sipe is It is preferable that the tire is disposed in the center land portion between the tire center line and the inner end portion of the lug groove in the tire width direction.

  Since the 2nd sipe connected to the inner edge part of a lug groove is provided in a center land part, wet performance and abrasion resistance performance can be improved more. If the second sipe in the center land portion is replaced with a lug groove, the wet performance is improved, but the wear resistance is deteriorated because the tread rigidity is lowered. Further, when the lug groove in the center land portion is replaced with the second sipe, the tread rigidity is increased, so that the wear resistance performance is improved, but the wet performance is deteriorated. By connecting the second sipe to the inner end portion of the lug groove penetrating the circumferential main groove, the wet performance and the wear resistance performance can be further improved.

In the aspect of the present invention, the second sipe is connected to the inner end portion of the lug groove, and is connected to the first straight portion that is inclined inward in the tire circumferential direction toward the inner side in the tire width direction. And a second straight portion disposed on the inner side in the tire width direction than the first straight portion, wherein the first straight portion is inclined at an angle α with respect to a reference line parallel to the tire centerline, The second straight line portion is inclined at an angle β with respect to the reference line,
30 [°] ≦ α ≦ 60 [°] (1A)
0 [°] ≦ β ≦ 8 [°] (2A)
It is preferable that the above condition is satisfied.

  When the angle α is smaller than 30 [°], the angle formed by the lug groove and the first straight portion of the second sipe becomes too small, and the tread rigidity is locally reduced, so that the uneven wear performance is deteriorated. On the other hand, when the angle α is larger than 60 [°], the second sipe is arranged so as to divide the center land portion in the tire circumferential direction, and as a result, the tread rigidity is lowered, so that the wear resistance performance is deteriorated. To do. In addition, when the angle β is smaller than 0 [°], the tip end portion of the second linear portion is positioned in the vicinity of the lug groove, and as a result, the tread rigidity is lowered, so that the wear resistance performance is deteriorated. On the other hand, when the angle β is larger than 8 [°], the tip of the second straight line portion is positioned in the vicinity of the other circumferential main groove, and as a result, the tread rigidity is reduced, so that uneven wear resistance performance is improved. Getting worse. By defining the angle α and the angle β so as to satisfy the conditions of the expressions (1A) and (2A), the uneven wear resistance can be improved.

In addition,
35 [°] ≦ α ≦ 55 [°] (1B)
3 [°] ≦ β ≦ 6 [°] (2B)
It is more preferable that the above condition is satisfied. By defining the angle α and the angle β so as to satisfy the conditions of the expressions (1B) and (2B), the uneven wear resistance can be further improved.

In the aspect of the present invention, when the length of the first straight portion is L1, and the length of the second straight portion is L2,
1.5 ≦ L2 / L1 ≦ 3.0 (3A)
It is preferable that the above condition is satisfied.

  When L2 / L1 is smaller than 1.5, the length L2 of the second linear portion is too short, and as a result, it becomes difficult to obtain sufficient wet performance. On the other hand, when L2 / L1 is larger than 3.0, the length L2 of the second linear portion is too long, and the distance between the second sipes adjacent in the tire circumferential direction is shortened. The wear resistance performance deteriorates due to a decrease in the wear resistance. By defining the length L1 and the length L2 so as to satisfy the condition of the expression (3A), it is possible to improve wet performance and uneven wear resistance performance.

In addition,
2.0 ≦ L2 / L1 ≦ 2.7 (3B)
It is more preferable that the above condition is satisfied. By defining the length L1 and the length L2 so as to satisfy the condition of the expression (3B), the wet performance and the uneven wear resistance can be further improved.

In the aspect of the present invention, when the dimension in the tire width direction of the lug groove disposed in the center land portion is L3, and the dimension in the tire width direction of the lug groove disposed in the shoulder land portion is L4,
1.0 ≦ L3 / L4 ≦ 1.4 (4A)
It is preferable that the above condition is satisfied.

  When L3 / L4 is smaller than 1.0, the dimension L3 of the lug groove arranged in the center land portion is too short, and as a result, it becomes difficult to obtain sufficient wet performance. On the other hand, when L3 / L4 is larger than 1.4, the dimension L3 of the lug groove arranged in the center land portion is too long. As a result, the tread rigidity is lowered, and the wear resistance performance is deteriorated. By defining the dimension L3 and the dimension L4 so as to satisfy the condition of the formula (4A), the wet performance and the uneven wear resistance can be improved.

In addition,
1.2 ≦ L3 / L4 ≦ 1.3 (4B)
It is more preferable that the above condition is satisfied. By defining the dimension L3 and the dimension L4 so as to satisfy the condition of the formula (4B), the wet performance and the uneven wear resistance can be further improved.

In the aspect of the present invention, the distance between the tire center line and the tire ground contact edge in the tire width direction is W, and the distance between the tire center line and the outer end portion of the first sipe in the tire width direction is Ws. When
1.1 × W ≦ Ws ≦ 1.2 × W (5A)
It is preferable that the above condition is satisfied.

  When the distance Ws is smaller than 110 [%] of the distance W, the length of the first sipe on the outer side in the tire width direction is too short from the tire ground contact end. Since the drainage is reduced, the wet performance is deteriorated. On the other hand, when the distance Ws is larger than 120 [%] of the distance W, the length of the first sipe outside the tire ground contact end in the tire width direction is too long, and as a result, the tire width direction from the tire ground contact end. Since the outer tread rigidity is lowered, the uneven wear resistance of the shoulder land portion is deteriorated. By defining the distance W and the distance Ws so as to satisfy the condition of the expression (5A), it is possible to improve wet performance and uneven wear resistance.

In addition,
1.14 × W ≦ Ws ≦ 1.16 × W (5B)
It is more preferable that the above condition is satisfied. By defining the distance W and the distance Ws so as to satisfy the condition of the formula (5B), the wet performance and the uneven wear resistance can be further improved.

  The distance W is a half value of the tire contact width of the tread portion. Tire contact width refers to the tire width direction measured when a pneumatic tire is assembled on a regular rim, filled with regular internal pressure, placed vertically on a flat surface, and loaded with a regular load. The maximum value of the ground contact width.

  In the aspect of the present invention, it is preferable that the opening of the lug groove has a chamfered portion.

  By providing the chamfered portion, the groove opening area when the tread portion is grounded can be increased, so that the wet performance can be improved. Further, by providing the chamfered portion, it is possible to suppress uneven wear of the edge of the lug groove opening due to slippage of the surface of the tread portion when the tread portion is grounded. The width of the chamfered portion is preferably 1 [mm] or more and 2 [mm] or less, and the depth of the chamfered portion is preferably 20 [%] or more and 40 [%] or less of the groove depth of the lug groove.

  According to the aspect of the present invention, a pneumatic tire capable of improving wet performance and wear resistance performance is provided.

FIG. 1 is a perspective view showing an appearance of a pneumatic tire according to the present embodiment. FIG. 2 is a front view showing an appearance of the pneumatic tire according to the present embodiment. FIG. 3 is a meridional sectional view schematically showing the pneumatic tire according to the present embodiment. FIG. 4 is a meridional sectional view showing a part of the pneumatic tire according to the present embodiment. FIG. 5 is a plan view showing a part of the tread portion of the pneumatic tire according to the present embodiment. FIG. 6 is an enlarged view of a part of FIG. FIG. 7 is an enlarged view of a part of FIG. FIG. 8 is a chart showing the results of the evaluation test of the pneumatic tire according to the present invention. FIG. 9 is a chart showing the results of the evaluation test of the pneumatic tire according to the present invention. FIG. 10 is a chart showing the results of the evaluation test of the pneumatic tire according to the present invention. FIG. 11 is a chart showing the results of the evaluation test of the pneumatic tire according to the present invention. FIG. 12 is a chart showing the results of the evaluation test of the pneumatic tire according to the present invention.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings, but the present invention is not limited thereto. The components of the embodiments described below can be combined as appropriate. Some components may not be used.

<Overview of tires and definitions of terms>
FIG. 1 is a perspective view showing an appearance of a tire 1 according to this embodiment. FIG. 2 is a front view showing an appearance of the tire 1 according to the present embodiment. FIG. 3 is a cross-sectional view schematically showing the tire 1 according to this embodiment. The tire 1 is a pneumatic tire.

  The tire 1 includes a tread portion 10 and a side portion 7. The tread portion 10 includes a tread rubber 6. The side part 7 includes a side rubber 8.

  The tire 1 can rotate around the rotation axis AX while being mounted on the rim of the vehicle. FIG. 3 shows a cross section of the tire 1 passing through the rotation axis AX. The cross section of the tire 1 passing through the rotation axis AX is also referred to as a meridian cross section of the tire 1.

  In the present embodiment, the tire 1 is a passenger car tire. The passenger car tire refers to a tire defined in Chapter A of JATMA YEAR BOOK 2015 (Japan Automobile Tire Association Standard). The tire 1 may be a small truck tire defined in Chapter B, or a truck and bus tire defined in Chapter C.

  In this specification, the tire 1 will be described using the terms tire width direction, tire radial direction, and tire circumferential direction. The tire width direction refers to a direction parallel to the rotation axis AX. The tire radial direction refers to a radial direction with respect to the rotation axis AX. The tire circumferential direction refers to the rotation direction of the tire 1 around the rotation axis AX.

  In the present specification, the tire equator plane refers to a virtual plane passing through the center of the tire 1 in the tire width direction and is orthogonal to the rotation axis AX. The tire center line CL refers to a line where the tire equator plane and the tread portion 10 of the tire 1 intersect, and is also referred to as a tire equator line. The tire center line CL is a line passing through the center of the tire 1 in the tire width direction, and is defined in the tread portion 10 of the tire 1.

  In the present specification, the outer side in the tire width direction refers to a position far from or away from the tire center line CL in the tire width direction. The inner side in the tire width direction refers to a position close to or approaching the tire center line CL in the tire width direction. The outer side in the tire radial direction refers to a position far from or away from the rotation axis AX in the tire radial direction. The inner side in the tire radial direction refers to a position close to or approaching the rotation axis AX in the tire radial direction. One side in the tire circumferential direction refers to a direction designated in the tire circumferential direction. The other side in the tire circumferential direction refers to the opposite direction of the direction specified in the tire circumferential direction.

  The tire outer diameter OD indicating the outer diameter of the tire 1 is a diameter of the tire 1 when the tire 1 is assembled on a regular rim, filled with a regular internal pressure, and no load is applied to the tire 1. Say.

  The tire rim diameter RD indicating the rim diameter of the tire 1 refers to a rim diameter of a wheel suitable for the tire 1. The tire rim diameter RD is equal to the tire inner diameter.

  The tire total width SW indicating the total width of the tire 1 is the tire width direction when the tire 1 is assembled on a regular rim, filled with a regular internal pressure, and no load is applied to the tire 1 in the tire width direction. This is the maximum dimension of the tire 1. That is, the tire total width SW is a distance between the outermost portion of the side portion 7 disposed on one side of the tread rubber 6 and the outermost portion of the side portion 7 disposed on the other side in the tire width direction. Say. When the structure which protrudes from the surface of the side part 7 is provided in the surface of the side part 7, tire total width SW means the largest dimension of the tire 1 in the tire width direction containing the structure. The structure protruding from the surface of the side portion 7 includes at least one of characters, marks, and patterns formed by at least a part of the side rubber 8 in the side portion 7.

  The tire cross-sectional width S indicating the cross-sectional width of the tire 1 is the total tire width SW when the tire 1 is assembled on a normal rim, filled with a normal internal pressure, and no load is applied to the tire 1. The maximum dimension of the tire 1 in the tire width direction, excluding a structure including at least one of characters, marks, and patterns. That is, the tire cross-sectional width S is the maximum width position H indicating the outermost part of the side portion 7 disposed on one side of the tread rubber 6 in the tire width direction when the structure is excluded, and on the other side. The distance with the maximum width position H which shows the outermost site | part of the arrange | positioned side part 7 is said. A rim protect bar that protects the rim may be provided on the tire 1. The rim protect bar is provided in the tire circumferential direction and protrudes outward in the tire width direction. In the tire 1 provided with the rim protect bar, the rim protect bar includes the outermost portion in the tire width direction, but the tire cross-sectional width S is a dimension excluding the rim protect bar.

  The tire contact width TW indicating the contact width of the tread portion 10 is a state in which the tire 1 is assembled on a regular rim, filled with a regular internal pressure, placed vertically on a plane, and a normal load is applied. The maximum value of the contact width in the tire width direction, measured in. That is, the tire ground contact width TW refers to the distance between the tire ground contact end T of the tread portion 10 on one side of the tire center line CL and the tire ground contact end T of the other tread portion 10 in the tire width direction.

  The tire ground contact end T is a portion where the tire 1 is assembled on a regular rim, filled with a regular internal pressure, placed vertically on a plane, and the tread portion 10 contacts the ground when a regular load is applied. The end in the tire width direction. The tire ground contact edge T is defined by the tread portion 10.

  The tread development width TDW indicating the development width of the tread portion 10 is the tire 1 in a no-load state in which the tire 1 is assembled on a regular rim, filled with a regular internal pressure, and no load is applied to the tire 1. The linear distance of both ends in the development view of the tread portion 10 is said.

  The “regular rim” is a rim that is defined for each tire 1 in the standard system including the standard on which the tire 1 is based, and is a standard rim for JATMA, “Design Rim” for TRA, and ETRTO. If there is, it is “Measuring Rim”. However, when the tire 1 is a tire mounted on a new vehicle, a genuine wheel on which the tire 1 is assembled is used.

  The “normal internal pressure” is the air pressure determined for each tire 1 in the standard system including the standard on which the tire 1 is based. The maximum air pressure is JATMA, and the table “TIRE LOAD LIMITS AT VARIOUS” is TRA. In the case of ETRTO, the maximum value described in “COLD INFORATION PRESSURES” is “INFLATION PRESSURE”. However, when the tire 1 is a tire mounted on a new vehicle, the air pressure displayed on the vehicle is used.

  The “regular load” is a load determined by the standard for each tire 1 in the standard system including the standard on which the tire 1 is based. The maximum load capacity is set for JATMA, and the table “TIRE LOAD LIMITS AT” is set for TRA. If it is ETRTO, the maximum value described in “VARIOUS COLD INFRATION PRESURES” is “LOAD CAPACITY”. However, when the tire 1 is a passenger car, the load is equivalent to 88% of the load. When the tire 1 is a tire mounted on a new vehicle, the wheel load is obtained by dividing the longitudinal axle weight described in the vehicle verification of the vehicle by the number of tires.

  The tread rubber 6 of the tread portion 10 is provided with a plurality of grooves, and a tread pattern is formed on the tread portion 10 by the plurality of grooves. A land portion is provided between the grooves. The land portion has a ground contact surface (tread surface) that can contact the road surface. In the present embodiment, the groove provided in the tread portion 10 includes a circumferential main groove, a lug groove, and a sipe.

  The circumferential main groove has a groove width of 1.0 [mm] or more, a groove depth of 4.0 [mm] or more, and a tread so that at least a part thereof extends in the tire circumferential direction. The vertical groove provided in the part 10 is said. In general, the circumferential main groove has a groove width of 6.0 [mm] or more and a groove depth of 7.0 [mm] or more. The circumferential main groove has a tread wear indicator (slip sign) inside. The treadwear indicator indicates the end of wear.

  In the present embodiment, the circumferential main groove is substantially parallel to the tire center line CL. The circumferential main groove extends linearly in the tire circumferential direction. The circumferential main groove may be provided in a wave shape or a zigzag shape in the tire circumferential direction.

  The lug groove has a groove width of 1.5 [mm] or more, a groove depth of 3.0 [mm] or more, and at least part of the tread portion 10 extends in the tire width direction. The horizontal groove provided in The lug groove is a groove in which the groove opening of the lug groove does not close even when the land portion around the lug groove is grounded, and is generally 1.5 [mm] or more and 10.0 [mm] or less. Has a groove width.

  The lug groove may have an open structure that penetrates the land portion in the tire width direction, a semi-closed structure in which one end portion terminates in the land portion, or a closed structure in which both end portions terminate in the land portion. . At least a part of the lug groove may be parallel to the tire width direction. The lug groove may be inclined with respect to each of the tire width direction and the tire circumferential direction. At least a part of the lug groove may be connected to the circumferential main groove.

  A sipe is a groove having a groove width of 0.6 [mm] or more and 1.0 [mm] or less. At least a part of the sipe may extend in the tire width direction or may extend in the tire circumferential direction. The sipe is a narrow groove that closes the groove opening of the sipe when the land around the sipe is grounded.

  The groove width refers to the maximum value of the groove width on the ground contact surface (tread surface). The groove width is measured by excluding the notch and chamfer formed in the groove opening. The groove depth is the maximum value from the ground contact surface (tread surface) to the groove bottom. The groove depth is measured by excluding a partial uneven part formed at the groove bottom.

<Tire structure>
Next, the structure of the tire 1 will be described with reference to FIGS. 3 and 4. FIG. 4 is a meridional sectional view showing a part of the tire 1 according to the present embodiment.

  As shown in FIGS. 3 and 4, the tire 1 includes a carcass 2, a belt layer 3, a belt cover 4, a bead portion 5, a tread portion 10 including a tread rubber 6, and a side portion 7 including a side rubber 8. With.

  Each of the carcass 2, the belt layer 3, and the belt cover 4 includes a cord. The cord is a reinforcing material. The cord may be referred to as a wire. Each of the layers including a reinforcing material such as the carcass 2, the belt layer 3, and the belt cover 4 may be referred to as a cord layer or a reinforcing material layer.

  The carcass 2 is a strength member that forms the skeleton of the tire 1. The carcass 2 includes a cord. The carcass 2 cord may be referred to as a carcass cord. The carcass 2 functions as a pressure vessel when the tire 1 is filled with air. The carcass 2 is supported by the bead portion 5. The bead portion 5 is disposed on each of one side and the other side of the carcass 2 in the tire width direction. The carcass 2 is folded back at the bead portion 5. The carcass 2 includes an organic fiber carcass cord and rubber covering the carcass cord. The carcass 2 may include a polyester carcass cord, a nylon carcass cord, an aramid carcass cord, or a rayon carcass cord.

  The belt layer 3 is a strength member that maintains the shape of the tire 1. The belt layer 3 includes a cord. The cord of the belt layer 3 may be referred to as a belt cord. The belt layer 3 is disposed between the carcass 2 and the tread rubber 6. The belt layer 3 includes, for example, a belt cord made of metal fiber such as steel and rubber covering the belt cord. The belt layer 3 may include an organic fiber belt cord. In the present embodiment, the belt layer 3 includes a first belt ply 3A and a second belt ply 3B. The first belt ply 3A and the second belt ply 3B are laminated so that the cord of the first belt ply 3A and the cord of the second belt ply 3B intersect.

  The belt cover 4 is a strength member that protects and reinforces the belt layer 3. The belt cover 4 includes a cord. The cord of the belt cover 4 may be referred to as a cover cord. The belt cover 4 is disposed on the outer side in the tire radial direction than the belt layer 3. The belt cover 4 includes, for example, a cover cord made of metal fiber such as steel and rubber covering the cover cord. The belt cover 4 may include an organic fiber cover cord.

  The bead portion 5 is a strength member that fixes both ends of the carcass 2. The bead portion 5 fixes the tire 1 to the rim. The bead part 5 has a bead core 5A and a bead filler 5B. The bead core 5A is a member in which a bead wire is wound in a ring shape. The bead wire is a steel wire. The bead filler 5B is a rubber material disposed in a space formed by folding the end portion in the tire width direction of the carcass 2 at the position of the bead core 5A.

  The tread rubber 6 protects the carcass 2. A tread portion 10 is formed on the tread rubber 6. The tread portion 10 includes a ground contact surface (tread surface) that contacts the road surface.

  The side rubber 8 protects the carcass 2. The side rubber 8 is disposed on each of one side and the other side of the tread rubber 6 in the tire width direction. Side portions 7 are formed on the side rubber 8.

  The side portions 7 are provided on one side and the other side of the tread portion 10 in the tire width direction. The side portion 7 is disposed on the outer side in the tire width direction than the tire ground contact end T of the tread portion 10.

  The side portion 7 is a region on the surface of the tire 1 between the tire ground contact edge T of the tread portion 10 and the rim check line R. The rim check line R is a line for confirming whether or not the rim assembly of the tire 1 is normally performed. In general, the rim check line R is shown as an annular convex line that is continuous in the tire circumferential direction along the rim flange on the surface of the bead portion 5 outside the rim flange in the tire radial direction.

<Tread pattern>
Next, a tread pattern provided on the tread portion 10 of the tire 1 will be described with reference to FIGS. 4, 5, and 6. FIG. 5 is a plan view showing a part of the tread portion 10 of the tire 1 according to the present embodiment. FIG. 6 is an enlarged view of a part of FIG. As shown in FIG. 5, in this embodiment, the tread pattern of the tread portion 10 is a point-symmetric pattern. In the tire width direction, the tread pattern on one side of the tire center line CL and the tread pattern on the other side are substantially equal. FIG. 6 shows a tread pattern on one side of the tire center line CL. In the following description, only the tread pattern on one side of the tire center line CL will be described.

  A plurality of tread portions 10 are provided in the tire width direction, each provided in a circumferential main groove 20 extending in the tire circumferential direction, a plurality of land portions 30 partitioned by the circumferential main groove 20, and the land portion 30. Lug groove 40 to be provided. The circumferential main groove 20 and the lug groove 40 are formed in the tread rubber 6. The land portion 30 has a ground contact surface (tread surface) 11 that can contact the road surface.

  The circumferential main groove 20 extends in the tire circumferential direction. In the present embodiment, the circumferential main groove 20 is substantially parallel to the tire center line CL. The circumferential main groove 20 extends linearly in the tire circumferential direction.

  In the present embodiment, three circumferential main grooves 20 are provided in the tire width direction. The circumferential main groove 20 includes one center main groove 21 provided at the center in the tire width direction and two shoulder main grooves 22 provided outside the center main groove 21 in the tire width direction. In the present embodiment, the groove widths of the three circumferential main grooves 20 are substantially equal.

  The center main groove 21 is provided in the tread portion 10 along the tire center line CL. The tire center line CL passes through the center main groove 21.

  The shoulder main groove 22 is provided in the tread portion 10 so as to extend in the tire circumferential direction between the tire center line CL and the tire ground contact end T.

  In the present embodiment, four land portions 30 are provided in the tire width direction. The land portion 30 includes one center land portion 31 provided between the center main groove 21 and one shoulder main groove 22 of the two shoulder main grooves 22, the center main groove 21, and the two shoulder main grooves 22. Of these, the other center land portion 31 provided between the other shoulder main groove 22, one shoulder land portion 32 provided on the outer side in the tire width direction than the one shoulder main groove 22, and the other shoulder main groove 22. And the other shoulder land portion 32 provided on the outer side in the tire width direction.

  The center land portion 31 and the shoulder land portion 32 are partitioned by the shoulder main groove 22. The center land portion 31 is provided closer to the tire center line CL than the shoulder main groove 22. The shoulder land portion 32 is provided closer to the tire ground contact end T than the shoulder main groove 22. The tire ground contact edge T is defined by the shoulder land portion 32.

  The lug groove 40 includes a through lug groove 41 provided so as to penetrate the shoulder main groove 22, and a shoulder lug groove 42 at least partially disposed at the tire ground contact end T. A plurality of through lug grooves 41 are provided at regular intervals in the tire circumferential direction. A plurality of shoulder lug grooves 42 are provided at regular intervals in the tire circumferential direction.

  The through lug groove 41 extends substantially in the tire width direction. The through lug groove 41 has an inner end portion 41A on the inner side in the tire width direction and an outer end portion 41B on the outer side in the tire width direction.

  The inner end portion 41A of the through lug groove 41 is disposed in the center land portion 31 outside the tire center line CL in the tire width direction. That is, the through lug groove 41 and the center main groove 21 are not connected, and at least a part of the center land portion 31 is disposed between the through lug groove 41 and the center main groove 21 (tire center line CL). In other words, the inner end portion 41 </ b> A of the through lug groove 41 ends at the center land portion 31.

  The outer end portion 41 </ b> B of the through lug groove 41 is disposed in the shoulder land portion 32 on the inner side in the tire width direction than the tire ground contact end T. That is, the through lug groove 41 does not extend to the tire ground contact end T, and at least a part of the shoulder land portion 32 is disposed between the through lug groove 41 and the tire ground contact end T. In other words, the outer end portion 41 </ b> B of the through lug groove 41 ends at the shoulder land portion 32.

  The through lug groove 41 is not orthogonal to the tire center line CL and is slightly inclined with respect to the tire width direction. In the example shown in FIG. 6, the inner end portion 41 </ b> A of the through lug groove 41 is disposed on one side in the tire circumferential direction with respect to the outer end portion 41 </ b> B of the through lug groove 41.

  The shoulder lug groove 42 extends substantially in the tire width direction. The shoulder lug groove 42 has an inner end portion 42A on the inner side in the tire width direction and an outer end portion 42B on the outer side in the tire width direction.

  The inner end portion 42A of the shoulder lug groove 42 is disposed in the shoulder land portion 32 on the inner side in the tire width direction than the tire ground contact end T. The shoulder lug groove 42 and the shoulder main groove 22 are not connected, and at least a part of the shoulder land portion 32 is disposed between the shoulder lug groove 42 and the shoulder main groove 22. In other words, the inner end portion 42 </ b> A of the shoulder lug groove 42 terminates at the shoulder land portion 32.

  The outer end portion 42B of the shoulder lug groove 42 is disposed on the shoulder land portion 32 on the outer side in the tire width direction than the tire ground contact end T. That is, the shoulder lug groove 42 extends to the outer side in the tire width direction from the tire ground contact end T. The shoulder land portion 42 is provided so as to straddle the tire ground contact end T.

  The shoulder lug groove 42 is not orthogonal to the tire center line CL and is slightly inclined with respect to the tire width direction. In the example shown in FIG. 6, the inner end portion 42 </ b> A of the shoulder lug groove 42 is disposed on the other side in the tire circumferential direction with respect to the outer end portion 42 </ b> B of the shoulder lug groove 42.

  That is, the inclination direction of the through lug groove 41 with respect to the tire width direction is different from the inclination direction of the shoulder lug groove 42 with respect to the tire width direction.

  Further, the distance between the inner end portion 42A and the outer end portion 42B of the shoulder lug groove 42 (that is, the length of the shoulder lug groove 42) is the distance between the inner end portion 41A and the outer end portion 41B of the through lug groove 41 (that is, Longer than the length of the through lug groove 41).

  The outer end portion 41 </ b> A of the through lug groove 41 is disposed slightly on the outer side in the tire width direction than the inner end portion 42 </ b> A of the shoulder lug groove 42. The outer end 41A of the through lug groove 41 and the inner end 42A of the shoulder lug groove 42 are alternately arranged in the tire circumferential direction.

  The tread portion 10 includes a first sipe 51 that is connected to the outer end portion 41 </ b> B of the through lug groove 41 and is formed in the shoulder land portion 32.

  The first sipe 51 extends substantially in the tire width direction. The first sipe 51 is provided on the shoulder land portion 32 so as to extend from the outer end portion 41 </ b> B of the through lug groove 41 toward the outer side in the tire width direction.

  The first sipe 51 has an inner end portion 51A on the inner side in the tire width direction and an outer end portion 51B on the outer side in the tire width direction. The outer end 41B of the through lug groove 41 and the inner end 51A of the first sipe 51 are connected.

  The inner end portion 51 </ b> A of the first sipe 51 is disposed on the shoulder land portion 32 on the inner side in the tire width direction than the tire ground contact end T. The outer end portion 51 </ b> B of the first sipe 51 is disposed on the shoulder land portion 32 on the outer side in the tire width direction than the tire ground contact end T. The outer end portion 51 </ b> B of the first sipe 51 is terminated at the shoulder land portion 32.

  The first sipe 51 is not perpendicular to the tire center line CL and is slightly inclined with respect to the tire width direction. In the example illustrated in FIG. 6, the inner end portion 51 </ b> A of the first sipe 51 is disposed on one side in the tire circumferential direction with respect to the outer end portion 51 </ b> B of the first sipe 51.

  In the example shown in FIG. 6, the outer end 51 </ b> B of the first sipe 51 is disposed on the other side in the tire circumferential direction with respect to the outer end 41 </ b> B of the through lug groove 41.

  The tread portion 10 includes a second sipe 52 that is connected to the inner end portion 41 </ b> A of the through lug groove 41 and is formed in the center land portion 31.

  The second sipe 52 has an inner end 52A on the inner side in the tire width direction and an outer end 52B on the outer side in the tire width direction. The inner end 41 </ b> A of the through lug groove 41 and the outer end 52 </ b> B of the second sipe 52 are connected.

  In the example illustrated in FIG. 6, the outer end 52B of the second sipe 52 is disposed on one side in the tire circumferential direction with respect to the inner end 51A of the first sipe 51A.

  The outer end portion 52B of the second sipe 52 is disposed in the center land portion 31 outside the tire center line CL in the tire width direction. The inner end portion 52A of the second sipe 52 is disposed in the center land portion 31 between the tire center line CL (center main groove 21) and the inner end portion 41A of the through lug groove 41 in the tire width direction. That is, the second sipe 52 and the center main groove 21 are not connected, and at least a part of the center land portion 31 is disposed between the second sipe 52 and the center main groove 21 (tire center line CL). In other words, the inner end portion 52 </ b> A of the second sipe 52 ends at the center land portion 31.

  As shown in FIG. 6, the second sipe 52 is connected to the inner end portion 41 </ b> A of the through lug groove 41, and is inclined to the tire width direction inner side with respect to the tire circumferential direction one side, and the first straight portion 521. And a second straight part 522 that is connected to the part 521 and arranged on the inner side in the tire width direction than the first straight part 521. Similar to the first straight portion 521, the second straight portion 522 is inclined toward the tire circumferential direction side toward the inner side in the tire width direction.

  That is, the second sipe 52 has a bent portion 52C between the inner end portion 52A and the outer end portion 52B. The bent portion 52C is provided at the boundary between the first straight portion 521 and the second straight portion 522. In the tire circumferential direction, the bent portion 52C is disposed between the inner end portion 52A and the outer end portion 52B. In the example illustrated in FIG. 6, the bent portion 52C is disposed on one side in the tire circumferential direction with respect to the outer end portion 52B, and the inner end portion 52A is disposed on one side in the tire circumferential direction with respect to the bent portion 52C. Further, the bent portion 52C is disposed on the inner side in the tire width direction with respect to the outer end portion 52B, and the inner end portion 52A is disposed on the inner side in the tire width direction with respect to the bent portion 52C.

  As described above, in the present embodiment, the inner end portion 41 </ b> A of the through lug groove 41 ends at the center land portion 31, and the outer end portion 41 </ b> B of the through lug groove 41 ends at the shoulder land portion 32. The inner end portion 42 </ b> A of the shoulder lug groove 42 terminates at the shoulder land portion 32. The outer end portion 51 </ b> B of the first sipe 51 is terminated at the shoulder land portion 32, and the inner end portion 52 </ b> A of the second sipe 52 is terminated at the center land portion 31. That is, the center land portion 31 and the shoulder land portion 32 are not divided by the groove. In the present embodiment, the center land portion 31 and the shoulder land portion 32 are ribs (continuous land portions) in which the ground contact surface 11 is connected without interruption in the tire circumferential direction.

  FIG. 7 is an enlarged view of a part of FIG. As shown in FIG. 7, the first straight part 521 is inclined at an angle α with respect to a reference line RL parallel to the tire center line CL, and the second straight part 522 is a reference line RL parallel to the tire center line CL. With an angle β. The angle α and the angle β are determined so as to satisfy the conditions of the following expressions (1A) and (2A).

30 [°] ≦ α ≦ 60 [°] (1A)
0 [°] ≦ β ≦ 8 [°] (2A)

  It is more preferable that the angle α and the angle β are determined so as to satisfy the conditions of the following expressions (1B) and (2B).

35 [°] ≦ α ≦ 55 [°] (1B)
3 [°] ≦ β ≦ 6 [°] (2B)

  In addition, the angle γ formed by the through lug groove 41 and the reference line RL is preferably 50 [°] or more and 70 [°] or less.

  Further, when the length of the first straight portion 521 is L1 and the length of the second straight portion 522 is L2, the length L1 and the length L2 satisfy the following expression (3A). Determined.

  1.5 ≦ L2 / L1 ≦ 3.0 (3A)

  In addition, it is more preferable that the length L1 and the length L2 are determined so as to satisfy the condition of the following expression (3B).

  2.0 ≦ L2 / L1 ≦ 2.7 (3B)

  The length L1 includes the distance between the outer end portion 52B and the bent portion 52C. The length L2 includes the distance between the bent portion 52C and the inner end portion 52A. In addition, it is preferable that length L1 is 5 [mm] or more and 10 [mm] or less. The length L2 is preferably 10 [mm] or more and 30 [mm] or less.

  Further, when the dimension in the tire width direction of the through lug groove 41 disposed in the center land portion 31 is L3 and the dimension in the tire width direction of the through lug groove 41 disposed in the shoulder land portion 32 is L4, the length L3 and length L4 are determined so as to satisfy the condition of the following expression (4A).

  1.0 ≦ L3 / L4 ≦ 1.4 (4A)

  In addition, it is more preferable that the length L3 and the length L4 are determined so as to satisfy the condition of the following expression (4B).

  1.2 ≦ L3 / L4 ≦ 1.3 (4B)

  The length L3 is in the tire width direction between the boundary between the through lug groove 41 arranged in the center land portion 31 and the edge of the shoulder main groove 22 on the tire center line CL side and the inner end portion 41A of the through lug groove 41. Includes distance. The length L4 is in the tire width direction between the boundary between the through lug groove 41 disposed in the shoulder land portion 32 and the edge of the shoulder main groove 22 on the tire ground contact end T side and the outer end portion 41B of the through lug groove 41. Includes distance. In addition, it is preferable that length L3 is 5 [mm] or more and 20 [mm] or less. The length L4 is preferably 5 [mm] or more and 15 [mm] or less.

  Further, when the dimension of the second sipe 52 in the tire width direction is L5, L5 / L3 is preferably 0.4 or more and 0.8 or less. Moreover, it is preferable that the dimension L5 is 3 [mm] or more and 10 [mm] or less.

  When the dimension of the first sipe 51 in the tire width direction is L6, L6 / L4 is preferably 2.0 or more and 3.0 or less. Moreover, it is preferable that the dimension L6 is 15 [mm] or more and 35 [mm] or less.

  Moreover, as shown in FIG. 7, in this embodiment, the groove opening part (opening) of the penetration lug groove 41 is chamfered, and the chamfer part 12 is provided. The width Wm of the chamfered portion 12 is preferably 1 [mm] or more and 2 [mm] or less, and the depth of the chamfered portion 12 is preferably 20 [%] or more and 40 [%] or less of the groove depth of the through lug groove 41. .

  As described above, the lug groove 40 is a groove having a groove width of 1.5 [mm] or more and 10.0 [mm]. A sipe is a groove having a groove width of 0.6 [mm] or more and 1.0 [mm] or less. In the present embodiment, the groove width Wr of the through lug groove 41 is determined to be at least twice the groove width Wp1 of the first sipe 51 and the groove width Wp2 of the second sipe 52. For example, when the groove width Wp1 of the first sipe 51 and the groove width Wp2 of the second sipe 52 are 0.8 [mm], the groove width Wr of the through lug groove 41 is set to at least 1.6 [mm]. . The difference between the groove width Wr and the groove width Wp1 is preferably at least 1.0 [mm], and the difference between the groove width Wr and the groove width Wp2 is at least 1.0 [mm]. preferable. In the present embodiment, the groove width Wp1 of the first sipe 51 and the groove width Wr of the through lug groove 41 change stepwise, and the groove width Wp2 of the second sipe 52 and the groove width Wr of the through lug groove 41 differ. It changes step by step.

  Further, as shown in FIG. 6, the distance between the tire center line CL and the tire ground contact end T in the tire width direction is W, and the distance between the tire center line CL and the outer end portion 51B of the first sipe 51 in the tire width direction. When Ws, the distance W and the distance Ws are determined so as to satisfy the condition of the following expression (5A).

  1.1 × W ≦ Ws ≦ 1.2 × W (5A)

  The distance W and the distance Ws are more preferably determined so as to satisfy the condition of the following expression (5B).

  1.14 × W ≦ Ws ≦ 1.16 × W (5B)

  The distance W is a half value of the tire ground contact width TW, and the relationship of W = 0.5 × TW is established. An outer end portion 51B of the first sipe 51 provided on one side in the tire width direction with respect to the tire center line CL, and an outer end portion 51B of the first sipe 51 provided on the other side in the tire width direction When the distance in the tire width direction is Ts, the distance Ws is a half value of the distance Ts, and the relationship of Ws = 0.5 × Ts is established.

  As shown in FIG. 6, the through lug groove 41 and the shoulder lug groove 42 are arranged at a constant interval Pa in the tire circumferential direction. The interval Pb between the plurality of first sipes 51 arranged in the tire circumferential direction is substantially equal to the interval Pa. The distance Pc in the tire circumferential direction between the inner end 52A of one second sipe 52 and the outer end 52B of the other second sipe 52 of the two second sipes 52 adjacent in the tire circumferential direction is equal to the distance Pb. It is preferably set to 12 [%] or more and 17 [%] or less. The interval Pc is preferably set to 3 [mm] or more and 10 [mm] or less.

  When the dimension in the tire width direction of the center land portion 31 is Wa, and the distance in the tire width direction between the inner end portion 52A of the second sipe 52 and the center main groove 21 is Wb, Wb / Wa is 22 [ %] Or more and 27 [%] or less. The distance Wb is preferably 3 [mm] or more and 10 [mm] or less.

<Action and effect>
As described above, according to the present embodiment, the through lug groove 41 is provided so as to penetrate the shoulder main groove 22 that partitions the center land portion 31 and the shoulder land portion 32, and the outer end of the through lug groove 41 is provided. Since the 1st sipe 51 connected to the part 41B is provided in the shoulder land part 32, wet performance and abrasion resistance performance can be improved. If the first sipe 51 of the shoulder land portion 32 is replaced with the through lug groove 41 and the long through lug groove 41 is formed, the outer end 41B of the through lug groove 41 is located on the outer side in the tire width direction from the tire ground contact end T. The wet performance is improved due to the arrangement, but the wear resistance is deteriorated because the tread rigidity is lowered. Further, when the through lug groove 41 of the shoulder land portion 32 is replaced with the first sipe 51 and only the first sipe 51 is provided in the shoulder land portion 32 without providing the through lug groove 41, the tread rigidity is increased, so that wear resistance is increased. Performance improves, but wet performance deteriorates. By connecting the first sipe 51 to the outer end 41B of the through lug groove 41 penetrating the shoulder main groove 22, both wet performance and wear resistance can be achieved.

  Further, according to the present embodiment, the first sipe 51 extends to the outer side in the tire width direction from the tire ground contact end T. When the outer end portion 51B of the first sipe 51 is disposed on the inner side in the tire width direction than the tire ground contact end T, it is difficult to obtain sufficient wet performance. By disposing the outer end portion 51B of the first sipe 51 on the outer side in the tire width direction with respect to the tire ground contact end T, drainage is improved and sufficient wet performance can be obtained.

  In the present embodiment, that the through lug groove 41 penetrates the shoulder main groove 22 means that the substantially center of the single linear or arc-shaped through lug groove 41 is disposed in the shoulder main groove 22.

  Further, according to the present embodiment, the second sipe 52 connected to the inner end portion 41A of the through lug groove 41 is provided in the center land portion 31, and the inner end portion 52A of the second sipe 52 is arranged in the tire width direction. Arranged in the center land portion 31 between the tire center line CL and the inner end portion 41 </ b> A of the through lug groove 41. Since the second sipe 52 connected to the inner end portion 41A of the through lug groove 41 is provided in the center land portion 31, the wet performance and the wear resistance performance can be further improved. If the long through lug groove 41 is formed by replacing the second sipe 52 of the center land portion 31 with the through lug groove 41, the wet performance is improved, but the tread rigidity is lowered, so that the wear resistance performance is deteriorated. Further, when the through lug groove 41 of the center land portion 31 is replaced with the second sipe 52 and only the second sipe 52 is provided in the center land portion 31 without providing the through lug groove 41, the tread rigidity is increased and thus wear resistance is increased. Performance improves, but wet performance deteriorates. By connecting the second sipe 52 to the inner end 41 </ b> A of the through lug groove 41 that penetrates the shoulder main groove 22, wet performance and wear resistance can be further improved.

  In addition, according to the present embodiment, the second sipe 52 is connected to the inner end portion 41A of the through lug groove 41, and is inclined to the tire circumferential direction side toward the tire width direction inner side, And a second straight line portion 522 that is connected to the first straight line portion 521 and disposed on the inner side in the tire width direction than the first straight line portion 521. The angle α of the first straight line portion 521 with respect to the reference line RL and the angle β of the second straight line portion 522 with respect to the reference line RL satisfy the conditions of the above-described expressions (1A) and (2A). When the angle α is smaller than 30 [°], the angle formed between the through lug groove 41 and the first straight portion 521 of the second sipe 52 becomes too small, and the tread rigidity is locally reduced. Gets worse. On the other hand, when the angle α is larger than 60 [°], the second sipe 52 is arranged so as to divide the center land portion 31 in the tire circumferential direction, and as a result, the tread rigidity is reduced, so that the wear resistance performance is reduced. Gets worse. Further, when the angle β is smaller than 0 [°], the inner end portion 52A that is the tip portion of the second linear portion 522 is located in the vicinity of the through lug groove 41 that is arranged next in the tire circumferential direction, The interval Pc is reduced. As a result, since the tread rigidity is lowered, the wear resistance is deteriorated. On the other hand, when the angle β is larger than 8 [°], the inner end 52A, which is the tip of the second linear portion 522, is positioned in the vicinity of the center main groove 21, and the distance Wb is reduced. As a result, since the tread rigidity is lowered, the uneven wear resistance performance is deteriorated. By defining the angle α and the angle β so as to satisfy the conditions of the expressions (1A) and (2A), the uneven wear resistance can be improved.

  Further, by defining the angle α and the angle β so as to satisfy the conditions of the equations (1B) and (2B), the uneven wear resistance can be further improved.

  In the present embodiment, the length L1 of the first straight portion 521 and the length L2 of the second straight portion 522 satisfy the condition of the above-described formula (3A). When L2 / L1 is smaller than 1.5, the length L2 of the second linear portion 522 is too short, and as a result, it becomes difficult to obtain sufficient wet performance. On the other hand, when L2 / L1 is larger than 3.0, the length L2 of the second linear portion 522 is too long, and the interval Pc, which is the distance between the second sipes 52 adjacent in the tire circumferential direction, is shortened. As a result, since the tread rigidity is lowered, the wear resistance is deteriorated. By defining the length L1 and the length L2 so as to satisfy the condition of the expression (3A), it is possible to improve wet performance and uneven wear resistance performance.

  Further, by defining the length L1 and the length L2 so as to satisfy the condition of the expression (3B), it is possible to further improve wet performance and uneven wear resistance performance.

  In the present embodiment, the dimension L3 in the tire width direction of the through lug groove 41 disposed in the center land portion 31 and the dimension L4 in the tire width direction of the through lug groove 41 disposed in the shoulder land portion 32 are: The condition of the above-described expression (4A) is satisfied. When L3 / L4 is smaller than 1.0, the dimension L3 of the through lug groove 41 arranged in the center land portion 31 is too short, and as a result, it becomes difficult to obtain sufficient wet performance. On the other hand, when L3 / L4 is larger than 1.4, the dimension L3 of the through lug groove 41 arranged in the center land portion 31 is too long. As a result, the tread rigidity is lowered, so that the wear resistance performance is deteriorated. . By defining the dimension L3 and the dimension L4 so as to satisfy the condition of the formula (4A), the wet performance and the uneven wear resistance can be improved.

  In addition, by defining the dimension L3 and the dimension L4 so as to satisfy the condition of the formula (4B), the wet performance and the uneven wear resistance can be further improved.

  In the present embodiment, the distance W between the tire center line CL and the tire ground contact edge T in the tire width direction, and the distance Ws between the tire center line CL and the outer end portion 51B of the first sipe 51 in the tire width direction. Satisfies the condition of the above equation (5A). When the distance Ws is smaller than 110 [%] of the distance W, the length of the first sipe 51 on the outer side in the tire width direction than the tire ground contact end T is too short. As a result, the tire width is smaller than the tire ground contact end T. Since the drainage on the outside in the direction is reduced, the wet performance deteriorates. On the other hand, when the distance Ws is larger than 120 [%] of the distance W, the length of the first sipe 51 on the outer side in the tire width direction than the tire ground contact end T is too long. Since the tread rigidity on the outer side in the tire width direction is reduced, the uneven wear resistance performance of the shoulder land portion 32 is deteriorated. By defining the distance W and the distance Ws so as to satisfy the condition of the expression (5A), it is possible to improve wet performance and uneven wear resistance.

  In addition, by defining the distance W and the distance Ws so as to satisfy the condition of the expression (5B), it is possible to further improve the wet performance and the uneven wear resistance performance.

  In the present embodiment, the chamfered portion 12 is provided in the opening of the through lug groove 41. Since the chamfered portion 12 is provided, the groove opening area of the through lug groove 41 when the tread portion 10 is grounded can be increased, so that the wet performance can be improved. Further, by providing the chamfered portion 12, it is possible to suppress uneven wear at the edge of the opening of the through lug groove 41 due to slippage of the grounding surface 11 of the tread portion 10 when the tread portion 10 is grounded.

<Example>
Next, the result of the evaluation test of the tire 1 according to the present invention, the tire 1 according to the conventional example, and the tire 1 according to the comparative example will be described. 8, FIG. 9, FIG. 10, FIG. 11, and FIG. 12 are charts showing the results of the evaluation test of the tire 1 according to the present invention.

  As shown in FIG. 8, the tire 1 according to the conventional example is provided with the first sipe 51 and the second sipe 52 although the through lug groove 41 belonging to the technical scope of the present invention is provided. There is no tire. The tire 1 according to the comparative example is a tire in which the through lag groove 41 and the second sipe 52 belonging to the technical scope of the present invention are provided, but the first sipe 51 is not provided.

  As shown in FIG. 8, the tire 1 according to the first embodiment is a tire provided with a through lug groove 41 and a first sipe 51 belonging to the technical scope of the invention according to the present application. As shown in FIGS. 8 to 12, the tire 1 according to Examples 2 to 23 includes a through lug groove 41, a first sipe 51, and a second sipe 52 that belong to the technical scope of the invention according to the present application. The tire is provided. In the tire 1 according to the example 1 to the example 23, the relationship between the angle α and the angle β described above, the relationship between the length L1 and the length L2, the relationship between the distance W and the distance Ws, the dimension L3 and the dimension L4, And the conditions of the presence or absence of the chamfered portion 12 are changed.

  In the evaluation test, the tire 1 having a tire size of 195 / 65R15 91H (15 × 6J) was used in all of the tire 1 according to the conventional example, the tire 1 according to the comparative example, and the tire 1 according to the example. The air pressure of the tire 1 was 200 [kPa]. The tire 1 was mounted on a test vehicle that is a front-wheel drive vehicle with a displacement of 1.4 L, and an evaluation test was performed on a test course. The evaluation items were wet performance and wear resistance performance.

(Wet performance evaluation)
In the wet performance evaluation, the wet road surface was traveled at a traveling speed of 100 [km / h], and the braking distance when performing ABS braking was compared and evaluated. It evaluated with the index | index which makes the braking distance in the tire 1 which concerns on a prior art example a reference value (100), and it evaluated that wet performance was excellent, so that a numerical value was high.

(Abrasion resistance evaluation)
In the wear resistance performance evaluation, a flat road surface was run at 10,000 [km] at an average running speed of 80 [km / h], and the amount of wear after running was quantified by visual observation. Evaluation was performed using an index with the amount of wear in the tire 1 according to the conventional example as a reference value (100), and the higher the numerical value, the better the wear resistance.

  As shown in FIGS. 8 to 12, according to the tire 1 belonging to the technical scope of the invention according to the present application, it was confirmed that both wet performance and wear resistance performance can be achieved.

1 tire (pneumatic tire)
2 Carcass 3 Belt layer 3A First belt ply 3B Second belt ply 4 Belt cover 5 Bead portion 5A Bead core 5B Bead filler 6 Tread rubber 7 Side portion 8 Side rubber 10 Tread portion 11 Ground surface 12 Chamfered portion 20 Circumferential main groove 21 Center Main groove 22 shoulder main groove 30 land portion 31 center land portion 32 shoulder land portion 40 lug groove 41 through lug groove 41A inner end portion 41B outer end portion 42 shoulder lug groove 42A inner end portion 42B outer end portion 51 first sipe 51A inside End 51B Outer end 52 Second sipe 52A Inner end 52B Outer end 52C Bent part 521 First straight part 522 Second straight part AX Rotation axis CL Tire center line H Maximum width position OD Tire outer diameter R Rim check line RD Tire rim diameter RL Reference line S Tire cross-sectional width SW Tire total width T Tire ground contact edge TDW Tread deployment width TW Tire contact width W Distance Ws Distance

Claims (7)

A pneumatic tire having a tread portion in which a tire center line passing through the center in the tire width direction and a tire ground contact end are defined,
A circumferential main groove provided in the tread portion so as to extend in the tire circumferential direction between the tire center line and the tire ground contact edge;
A center land portion that is partitioned by the circumferential main groove and is provided closer to the tire center line than the circumferential main groove;
A shoulder land portion that is partitioned by the circumferential main groove and is provided closer to the tire ground contact end than the circumferential main groove;
Lug grooves provided so as to penetrate the circumferential main grooves,
A first sipe connected to the outer end of the lug groove in the tire width direction and formed on the shoulder land portion;
With
The inner end portion of the lug groove is disposed in the center land portion outside the tire center line in the tire width direction,
The outer end portion of the lug groove is disposed in the shoulder land portion on the inner side in the tire width direction than the tire ground contact end,
An outer end portion on the outer side in the tire width direction of the first sipe is disposed on the shoulder land portion on the outer side in the tire width direction with respect to the tire ground contact end.
Pneumatic tire. A second sipe connected to the inner end of the lug groove in the tire width direction and formed in the center land portion;
The inner end portion of the second sipe on the inner side in the tire width direction is disposed in the center land portion between the tire center line and the inner end portion of the lug groove in the tire width direction.
The pneumatic tire according to claim 1. The second sipe is connected to the inner end portion of the lug groove and is inclined to the tire circumferential direction side toward the tire width direction inner side, and is connected to the first straight portion and the first straight portion. Including a second straight portion disposed on the inner side in the tire width direction than,
The first straight portion is inclined at an angle α with respect to a reference line parallel to the tire center line,
The second straight portion is inclined at an angle β with respect to the reference line;
30 [°] ≦ α ≦ 60 [°],
0 [°] ≦ β ≦ 8 [°],
Satisfy the conditions of
The pneumatic tire according to claim 2. The length of the first straight portion is L1,
When the length of the second straight portion is L2,
1.5 ≦ L2 / L1 ≦ 3.0,
Satisfy the conditions of
The pneumatic tire according to claim 3. The dimension in the tire width direction of the lug groove arranged in the center land portion is L3,
When the dimension in the tire width direction of the lug groove arranged in the shoulder land portion is L4,
1.0 ≦ L3 / L4 ≦ 1.4,
Satisfy the conditions of
The pneumatic tire according to any one of claims 1 to 4. The distance between the tire center line and the tire ground contact edge in the tire width direction is W,
When the distance between the tire center line in the tire width direction and the outer end of the first sipe is Ws,
1.1 × W ≦ Ws ≦ 1.2 × W,
Satisfy the conditions of
The pneumatic tire according to any one of claims 1 to 5. A chamfered portion at the opening of the lug groove;
The pneumatic tire according to any one of claims 1 to 6.

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