JP5981900B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire that achieves both wear resistance performance and ride comfort performance.

  With the recent increase in vehicle output, pneumatic tires are required to have excellent wear resistance.

  In order to improve wear resistance performance, a pneumatic tire has been proposed in which the groove provided in the tread portion is reduced to increase the rigidity of the tread portion. However, such a pneumatic tire has a problem of reducing wet performance and riding comfort performance.

  Patent Document 1 below proposes a pneumatic tire in which the groove arrangement and the groove width are defined in order to improve the wet performance while maintaining the rigidity of the tread portion.

JP-A-11-278016

  However, the pneumatic tire disclosed in Patent Document 1 has room for further improvement in terms of both wear resistance and ride comfort.

  The present invention has been devised in view of the actual situation as described above, and on the basis of prescribing the shape and arrangement of grooves provided in the middle land portion and the shoulder land portion, wear resistance performance and ride comfort performance are provided. The main purpose is to provide a compatible pneumatic tire.

  The present invention provides a tread portion having a pair of shoulder main grooves extending continuously in the tire circumferential direction on both sides of the tire equator and closest to the tread grounding end, and extending between the pair of shoulder main grooves in the tire circumferential direction. By providing the center main groove, a pair of middle land portions between the shoulder main groove and the center main groove and a pair of shoulder land portions on the outer side in the tire axial direction of the shoulder main grooves are provided. The middle land portion includes a middle sipe communicating between the center main groove and the shoulder main groove, one end communicating with the shoulder main groove, and the other end within the middle land portion. A plurality of middle lug grooves that terminate in the tire circumferential direction and middle vertical grooves that extend in the tire circumferential direction are provided, and the middle vertical grooves are connected to the middle sipes and the middle lug grooves. The shoulder land portion has at least a shoulder lug groove extending inward in the tire axial direction from the tread ground end and terminating in the shoulder land portion, and a shoulder vertical portion extending in the tire circumferential direction. A plurality of grooves are provided, and the shoulder longitudinal grooves terminate in the shoulder land portion without communicating with the shoulder lug grooves.

  In the pneumatic tire according to the present invention, a pair of the center main grooves are provided on both sides of the tire equator, and one end of the center main groove between the pair of center main grooves communicates with the center main groove and the other. It is desirable that a plurality of center lug grooves whose ends terminate in the center land portion are provided.

  In the pneumatic tire according to the present invention, the middle sipe is a cut having substantially no width, and the middle land portion is provided with a lateral groove communicating with the center main groove and the shoulder main groove in addition to the middle sipe. It is desirable that the rib be continuous in the tire circumferential direction.

  In the pneumatic tire according to the present invention, it is preferable that the middle vertical groove is provided on the inner side in the tire axial direction than the middle lug groove.

  In the pneumatic tire according to the present invention, it is preferable that the middle lug groove extends in parallel with the middle sipe.

  In the pneumatic tire according to the present invention, the middle sipe is preferably inclined at an angle of 30 to 60 ° with respect to the tire circumferential direction.

  In the pneumatic tire according to the present invention, it is preferable that a shoulder auxiliary sipe extending from an inner end in the tire axial direction of the shoulder lug groove to the shoulder main groove is provided in the shoulder land portion.

  The pneumatic tire of the present invention has a pair of shoulder main grooves extending continuously in the tire circumferential direction on both sides of the tire equator and at the most tread grounding end side in the tread portion, and continuous between the pair of shoulder main grooves in the tire circumferential direction. By providing the center main groove extending, a pair of middle land portions between the shoulder main groove and the center main groove and a pair of shoulder land portions on the outer side in the tire axial direction of each shoulder main groove are provided. ing.

  The middle land portion has a middle sipe communicating between the center main groove and the shoulder main groove, a middle lug groove having one end communicating with the shoulder main groove and the other end terminating in the middle land portion, and a middle extending in the tire circumferential direction. A plurality of longitudinal grooves are provided. Such a middle land portion has high rigidity in the tire circumferential direction and exhibits excellent wear resistance.

  The middle vertical groove terminates in the middle land portion without communicating with the middle sipe and middle lug groove. Such middle vertical grooves suppress uneven wear near the ends of the grooves. Moreover, such middle vertical grooves ease the rigidity of the middle land portion in the tire axial direction while maintaining the rigidity of the middle land portion in the tire circumferential direction. For this reason, the pneumatic tire of the present invention exhibits excellent riding comfort performance while maintaining wear resistance.

  The shoulder land portion is provided with a plurality of shoulder lug grooves extending at least inward in the tire axial direction from the tread ground contact end and terminating in the shoulder land portion, and shoulder longitudinal grooves extending in the tire circumferential direction. Such a shoulder land portion has high rigidity in the tire circumferential direction and exhibits excellent wear resistance.

  The shoulder longitudinal groove terminates in the shoulder land portion without communicating with the shoulder lug groove. Such shoulder flutes suppress uneven wear near the ends of the grooves. In addition, such shoulder longitudinal grooves ease the rigidity of the shoulder land portion in the tire axial direction while maintaining the rigidity of the shoulder land portion in the tire circumferential direction. For this reason, excellent riding comfort performance is exhibited while maintaining wear resistance.

  Therefore, the pneumatic tire of the present invention achieves both wear resistance performance and ride comfort performance.

It is an expanded view of the tread part of the pneumatic tire of this embodiment. It is AA sectional drawing of FIG. It is an enlarged view of the middle land part of FIG. It is an enlarged view of the shoulder land part of FIG. It is an enlarged view of the center land part of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a tread portion 2 of a pneumatic tire (hereinafter sometimes simply referred to as “tire”) 1 of the present embodiment. The pneumatic tire 1 of this embodiment is shown as a pneumatic tire for passenger cars, for example.

  As shown in FIG. 1, the tread portion 2 is provided with a pair of shoulder main grooves 3 and 3 and a pair of center main grooves 4 and 4.

  The shoulder main groove 3 extends continuously in the tire circumferential direction on both sides of the tire equator C and on the tread ground contact end Te side. The shoulder main groove 3 of the present embodiment has a substantially constant groove width W1 and extends linearly.

  The “tread grounding end Te” is assembled with a normal rim (not shown) and filled with a normal internal pressure, and a normal load is applied to the normal tire 1 in an unloaded state so that the camber angle is 0 °. This is the ground contact position on the outermost side in the tire axial direction when grounding on the plane.

  The “regular rim” is a rim determined for each tire in a standard system including a standard on which a tire is based. For example, “Standard Rim” for JATMA, “Design Rim” for TRA, For ETRTO, "Measuring Rim".

  The “regular internal pressure” is an air pressure determined by each standard for each tire in the standard system including the standard on which the tire is based. The maximum value described in “AT VARIOUS COLD INFLATION PRESSURES”, “INFLATION PRESSURE” in the case of ETRTO.

  The “regular load” is a load determined by each standard for each tire in the standard system including the standard on which the tire is based. “JATMA” indicates “maximum load capacity”, and TRA indicates “TIRE LOAD”. The maximum value described in “LIMITS AT VARIOUS COLD INFLATION PRESSURES”, “LOAD CAPACITY” in the case of ETRTO.

  The center main groove 4 extends continuously between the shoulder main grooves 3 and 3 in the tire circumferential direction. A pair of center main grooves 4 of the present embodiment are provided on both sides of the tire equator C. The center main groove 4 has, for example, a substantially constant groove width W2 and extends linearly. For example, only one center main groove 4 may be provided on the tire equator C.

  The groove width W1 of the shoulder main groove 3 and the groove width W2 of the center main groove 4 are, for example, 3.0 to 5.0% of the tread grounding width TW. Such shoulder main groove 3 and center main groove 4 effectively drain the water film between the road surface and the tread portion 2 during wet running, and improve the wet performance. The tread contact width TW is a distance in the tire axial direction between the tread contact ends Te and Te of the tire 1 in a normal state.

  FIG. 2 is a cross-sectional view taken along the line AA in FIG. As shown in FIG. 2, the groove depths d1 and d2 of the shoulder main groove 3 and the center main groove 4 are preferably 5 to 10 mm, for example.

  As shown in FIG. 1, the tread portion 2 is divided into a middle land portion 10, a shoulder land portion 20, and a center land portion 30.

  The middle land portion 10 is provided between the shoulder main groove 3 and the center main groove 4. A pair of middle land portions 10 are provided on both sides of the tire equator C.

  FIG. 3 shows an enlarged view of the middle land portion 10. As shown in FIG. 3, the middle land portion 10 has a maximum width W3 in the tire axial direction. The width W3 of the middle land portion 10 is preferably 0.12 to 0 of the tread ground contact width TW (shown in FIG. 1 and the same hereinafter) in order to exhibit excellent wear resistance performance and riding comfort performance. 18 times.

  The middle land portion 10 is provided with a plurality of middle sipes 11, middle lug grooves 12, and middle longitudinal grooves 13, respectively.

  The middle sipe 11 communicates between the center main groove 4 and the shoulder main groove 3. In this specification, the “sipe” is a cut having a width of about 1 mm or less, which is substantially free of width, and is distinguished from a draining groove.

  The middle sipe 11 extends linearly. The middle sipe 11 is inclined at an angle θ1 with respect to the tire circumferential direction. The angle θ1 of the middle sipe 11 is preferably 35 ° or more, more preferably 40 ° or more, preferably 55 ° or less, more preferably 45 ° or less. Such a middle sipe 11 maintains the rigidity of the tread portion 2 and exhibits excellent wear resistance.

  The groove depth d3 (shown in FIG. 2) of the middle sipe 11 is preferably 3.5 mm or more, more preferably 4.0 mm or more, preferably 5.5 mm or less, more preferably 5.0 mm or less. Such a middle sipe 11 achieves both wear resistance performance and ride comfort performance.

  The middle sipe 11 communicates with the center main groove 4 through the widened portion 14. The widened portion 14 gradually increases the width of the middle sipe 11 toward the center main groove 4. Such a widened portion 14 improves wet performance.

  The middle lug groove 12 is provided between the middle sipes 11 and 11. The middle lug groove 12 has an outer end 12 a in the tire axial direction communicating with the shoulder main groove 3, and an inner end 12 b in the tire axial direction terminates in the middle land portion 10. Such middle lug groove 12 maintains the rigidity of the middle land portion 10 on the inner side in the tire axial direction. For this reason, the wear resistance performance of the middle land portion 10 is improved.

  The middle lug groove 12 extends linearly. For example, the middle lug groove 12 is inclined in the same direction as the middle sipe 11. The angle θ2 of the middle lug groove 12 with respect to the tire circumferential direction is preferably 35 ° or more, more preferably 40 ° or more, preferably 55 ° or less, more preferably 50 ° or less. Such a middle lug groove 12 exhibits excellent wet performance while maintaining uneven wear of the middle land portion 10.

  In the present embodiment, the middle lug groove 12 extends in parallel with the middle sipe 11. That is, θ1 = θ2. Such a middle lug groove 12 makes the rigidity distribution of the middle land portion 10 uniform, and improves riding comfort performance.

  The length L1 of the middle lug groove 12 in the tire axial direction is preferably 0.40 times or more, more preferably 0.45 times or more, preferably 0.60 times or less, more than the width W3 of the middle land portion 10. Preferably it is 0.55 times or less. As a result, the wear resistance performance and the ride comfort performance of the middle land portion 10 are well balanced.

  The middle lug groove 12 has a substantially constant groove width W4. The groove width W4 of the middle lug groove 12 is preferably 0.50 times or more, more preferably 0.55 times or more, preferably 0.65 times or less, more preferably 0, the groove width W1 of the shoulder main groove 3. .60 times or less. Such a middle lug groove 12 improves the wet performance while maintaining the rigidity of the middle land portion 10.

  The groove depth d4 (shown in FIG. 2) of the middle lug groove 12 is preferably 5.5 mm or more, more preferably 6.0 mm or more, preferably 7.5 mm or less, more preferably 6.0 mm or less. Such middle lug grooves 12 improve wet performance while maintaining wear resistance.

  Middle lug grooves 12 and middle sipes 11 are provided alternately in the tire circumferential direction. Such middle lug groove 12 and middle sipe 11 make the middle land portion 10 uniform in rigidity distribution and exhibit excellent wear resistance.

  The middle vertical groove 13 extends on the middle land portion 10 in the tire circumferential direction. The middle vertical groove 13 does not communicate with the middle sipe 11 and the middle lug groove 12, and both ends terminate in the middle land portion 10. Such middle vertical grooves 13 suppress uneven wear near the ends of the grooves. Moreover, such middle vertical grooves 13 moderately moderate the rigidity of the middle land portion 10 in the tire axial direction while maintaining the rigidity of the middle land portion 10 in the tire circumferential direction. For this reason, excellent riding comfort performance is exhibited while the wear resistance performance of the middle land portion 10 is maintained.

  The middle vertical groove 13 is preferably provided on the inner side in the tire axial direction than the inner end 12 b of the middle lug groove 12. The distance L3 in the tire axial direction between the middle vertical groove 13 and the inner end 12b of the middle lug groove 12 is preferably 0.10 times or more, more preferably 0.15 times or more, the width W3 of the middle land portion 10 in the tire axial direction. It is preferably 0.25 times or less, more preferably 0.20 times or less. Thereby, the rigidity distribution of the middle land portion 10 becomes uniform, and wear resistance performance and riding comfort performance are compatible.

  The middle vertical groove 13 is preferably shifted in the tire circumferential direction with respect to the middle lug groove 12. In the present embodiment, one middle vertical groove 13 is provided on each side of the inner end 12 b of the middle lug groove 12 in the tire circumferential direction. Since the middle vertical groove 13 does not contact with the middle lug groove 12 at the same time, the resonance of the pumping sound is suppressed. Therefore, the noise performance is improved.

  The length L2 of the middle vertical groove 13 is preferably 5.0 mm or more, more preferably 8.0 mm or more, preferably 15.0 mm or less, more preferably 12.0 mm or less. Such middle longitudinal groove 13 exhibits excellent riding comfort performance while maintaining steering stability performance.

  The middle vertical groove 13 extends linearly with a substantially constant groove width W5. The groove width W5 of the middle vertical groove 13 is preferably 0.5 mm or more, more preferably 0.8 mm or more, preferably 1.5 mm or less, more preferably 1.2 mm or less. Such middle vertical groove 13 makes the wear resistance performance and riding comfort performance of the middle land portion 10 more effective.

  The groove depth d5 (shown in FIG. 2) of the middle vertical groove 13 is preferably 1.0 mm or more, more preferably 1.2 mm or more, preferably 2.0 mm or less, more preferably 1.8 mm or less. . Such middle vertical groove 13 maintains the rigidity of the tread portion 2 appropriately, and achieves both wear resistance performance and riding comfort performance.

  The middle land portion 10 is a rib continuous in the tire circumferential direction in which a lateral groove communicating with the center main groove 4 and the shoulder main groove 3 other than the middle sipe 11 is not provided. Such middle land portion 10 effectively maintains the rigidity in the tire circumferential direction and exhibits excellent wear resistance.

  As shown in FIG. 1, a pair of shoulder land portions 20 are provided on the outer sides in the tire axial direction of the respective shoulder main grooves 3 and 3.

  FIG. 4 shows an enlarged view of the shoulder land portion 20. As shown in FIG. 4, the shoulder land portion 20 has a substantially constant width W6. The maximum width W6 in the tire axial direction of the shoulder land portion 20 is preferably 0.20 to 0.26 times the tread ground contact width TW in order to achieve both wear resistance performance and riding comfort performance. Such a shoulder land portion 20 exhibits excellent wear resistance performance and riding comfort performance.

  The shoulder land portion 20 is provided with a plurality of shoulder lug grooves 21, shoulder longitudinal grooves 22, shoulder sipes 23, and shoulder auxiliary sipes 24.

  The shoulder lug groove 21 extends at least inward in the tire axial direction from the tread ground contact end Te and terminates in the shoulder land portion 20. The length L4 of the shoulder lug groove 21 in the tire axial direction is preferably not less than 0.60 times, more preferably not less than 0.65 times, preferably not more than 0.80 times the width W6 of the shoulder land portion 20. Preferably it is 0.75 times or less. Such a shoulder lug groove 21 maintains the wear resistance performance of the shoulder land portion 20 and exhibits excellent wandering performance.

  The groove width W7 of the shoulder lug groove is preferably 0.50 times or more, more preferably 0.55 times or more, preferably 0.70 times or less, more preferably 0.70 times or more the groove width W1 of the shoulder main groove 3. 65 times or less. Such a shoulder lug groove 21 exhibits excellent wet performance while maintaining the rigidity of the shoulder land portion 20. The shoulder lug groove 21 of the present embodiment has a substantially constant groove width W7.

  The shoulder auxiliary sipe 24 communicates between the inner end 21 i of the shoulder lug groove 21 and the shoulder main groove 3, for example. Such a shoulder auxiliary sipe 24 moderately relieves the rigidity of the shoulder land portion 20 on the inner side in the tire axial direction, and further balances the wear resistance performance and the riding comfort performance of the shoulder land portion 20.

  The shoulder longitudinal groove 22 extends along the tire circumferential direction. Both ends of the shoulder longitudinal groove 22 terminate in the shoulder land portion 20 without communicating with the shoulder lug groove 21 and the shoulder auxiliary sipes 24. Such shoulder longitudinal grooves 22 suppress uneven wear near the end portions. Moreover, the shoulder longitudinal groove 22 reduces the rigidity of the shoulder land portion 20 in the tire axial direction while maintaining the rigidity of the shoulder land portion 20 in the tire circumferential direction. For this reason, excellent riding comfort performance is exhibited while maintaining the wear resistance performance of the shoulder land portion 20.

  The shoulder longitudinal groove 22 is provided, for example, on the inner side in the tire axial direction than the inner end 21 i of the shoulder lug groove 21. Such a shoulder longitudinal groove 22 makes the shoulder land portion 20 uniform in rigidity distribution and achieves both wear resistance performance and riding comfort performance.

  The length L5 of the shoulder longitudinal groove 22 is preferably 5.0 mm or more, more preferably 8.0 mm or more, preferably 15.0 mm or less, more preferably 12.0 mm or less. Such shoulder longitudinal grooves 22 exhibit excellent riding comfort performance while maintaining steering stability performance.

  The groove width W8 of the shoulder longitudinal groove 22 is, for example, 0.5 to 1.5 mm. The depth d6 (shown in FIG. 2) of the shoulder longitudinal groove 22 is, for example, 1.0 to 2.0 mm. Such a shoulder longitudinal groove 22 maintains the rigidity of the shoulder land portion 20 moderately, and achieves both wear resistance performance and riding comfort performance. In the present embodiment, the shoulder longitudinal groove 22 extends linearly with a substantially constant groove width W8.

  One shoulder sipe 23 is provided between the shoulder lug grooves 21 adjacent to each other in the tire circumferential direction. In the present embodiment, the shoulder sipes 23 and the shoulder lug grooves 21 are provided alternately in the tire circumferential direction. The shoulder sipe 23 extends from the outer side of the tread grounding end Te toward the inner side in the tire axial direction. The shoulder sipe 23 extends substantially parallel to the shoulder lug groove 21. The shoulder sipe 23 terminates in the shoulder land portion 20. Such a shoulder sipe 23 makes the rigidity distribution of the shoulder land portion 20 uniform, suppresses uneven wear, and improves wet performance and wandering performance.

  The distance L6 in the tire axial direction between the inner end 23i of the shoulder sipe 23 and the shoulder longitudinal groove 22 is preferably 0.10 times or more, more preferably 0.15 times or more, preferably the width W6 of the shoulder land portion 20. Is 0.25 times or less, more preferably 0.20 times or less. Thereby, the rigidity distribution of the shoulder land portion 20 becomes more uniform.

  The shoulder land portion 20 is a rib continuous in the tire circumferential direction in which a lateral groove communicating with the tread ground contact Te and the shoulder main groove 3 is not provided. Such a shoulder land portion 20 has high rigidity in the tire circumferential direction and exhibits excellent wear resistance.

  FIG. 5 shows an enlarged view of the center land portion 30. As shown in FIG. 5, the center land portion 30 is provided between the pair of center main grooves 4 and 4.

  The center land portion 30 is a rib continuous in the tire circumferential direction. The maximum width W9 in the tire axial direction of the center land portion 30 is, for example, 0.1 to 0.15 times the tread ground contact width TW.

  The center land portion 30 is provided with a plurality of center lug grooves 31. Each center lug groove 31 has an outer end 31 a in the tire axial direction communicating with the center main groove 4, and an inner end 31 b in the tire axial direction terminates in the center land portion 30. Such a center lug groove 31 improves wet performance while maintaining the rigidity of the center land portion 30.

  The first center lug groove 31A provided on one side of the tire equator C and the second center lug groove 31B provided on the other side of the tire equator C are inclined in the same direction. Moreover, the second center lug groove 31B is provided on an extension line of the center line 31c of the first center lug groove 31A. Such first center lug groove 31A and second center lug groove 31B relieve the rigidity of the center land portion 30 in the tire circumferential direction, and further improve the riding comfort performance.

  For example, the center lug groove 31 is preferably inclined in the same direction as the middle lug groove 12 (shown in FIG. 1). The angle θ3 of the center lug groove 31 with respect to the tire circumferential direction is preferably 35 ° or more, more preferably 40 ° or more, preferably 55 ° or less, more preferably 50 ° or less. Such a center lug groove 31 exhibits excellent wet performance.

  The length L7 of the center lug groove 31 in the tire axial direction is preferably not less than 0.25 times, more preferably not less than 0.30 times, preferably not more than 0.45 times the width W9 of the center land portion 30. More preferably, it is 0.40 times or less. Such a center lug groove 31 maintains the rigidity of the center land portion 30 appropriately, and achieves both wear resistance performance and ride comfort performance.

  The center lug groove 31 has a substantially constant groove width W10. The groove width W8 of the center lug groove 31 is, for example, 3.0 to 4.0 mm. The groove depth d7 (shown in FIG. 2) of the center lug groove 31 is, for example, 5.5 to 6.5 mm. Such a center lug groove 31 maintains the rigidity of the center land portion 30 appropriately, and achieves both wear resistance performance and ride comfort performance.

  As a pneumatic tire for passenger cars of the present embodiment, the land ratio Lr of the tread portion 2 is preferably 70% or more, more preferably 73% or more, preferably 80% or less, more preferably 77% or less. . Thereby, wear resistance performance and riding comfort performance are compatible. The “land ratio” is a ratio Sb / Sa of the actual total ground contact area Sb to the total area Sa of the virtual ground contact surface in which all the grooves and sipes are filled between the tread ground contact Te and Te.

  Although the pneumatic tire of the present invention has been described in detail above, the present invention is not limited to the specific embodiment described above, and can be implemented with various modifications.

A pneumatic tire of size 195 / 65R15 having the basic pattern of FIG. As Comparative Example 1, a tire in which a middle lateral groove communicating with the center main groove and the shoulder main groove is provided in the middle land portion, and no middle sipe, middle vertical groove, and shoulder vertical groove are provided, was manufactured. As Comparative Example 2, a tire in which a middle sipe was provided on the tire of Comparative Example 1 was manufactured. These tires were mounted on the following test vehicles and tested for wear resistance and riding comfort. The common specifications and test methods for each tire are as follows.
Wearing rim: 15 × 6J
Tire internal pressure: 200kPa
Test vehicle: Front-wheel drive vehicle, displacement 1600cc
Tire mounting position: all wheels

<Abrasion resistance>
The amount of wear when the test vehicle traveled on a general road for 30000 km was measured. The evaluation is performed by the reciprocal of the amount of wear, and is displayed as an index with the value of Comparative Example 1 being 100. It shows that abrasion resistance performance is excellent, so that a numerical value is large.

<Ride comfort performance>
Riding comfort performance when running on a paved road with the test vehicle was tested by the driver's sensuality. A result is a score which sets comparative example 1 to 100, and shows that riding comfort performance is excellent, so that a numerical value is large.
The test results are shown in Table 1.

  As a result of the test, it was confirmed that the tires of the examples achieved both wear resistance performance and ride comfort performance.

2 Tread 3 Shoulder main groove 4 Center main groove 4
10 Middle land 10
11 Middle sipe 12 Middle lug groove 13 Middle vertical groove 20 Shoulder land part 21 Shoulder lug groove 22 Shoulder vertical groove

Claims (8)

A pair of shoulder main grooves extending continuously in the tire circumferential direction on both sides of the tire equator and on the tread grounding end side, and a center main groove extending continuously between the pair of shoulder main grooves in the tire circumferential direction on the tread portion; Is provided with a pair of middle land portions between the shoulder main groove and the center main groove, and a pair of shoulder land portions on the outer side in the tire axial direction of the shoulder main grooves. Because
The middle land portion includes a middle sipe that communicates between the center main groove and the shoulder main groove, a middle lug groove that has one end communicating with the shoulder main groove and the other end terminating in the middle land portion, and a tire. A plurality of middle vertical grooves extending in the circumferential direction are provided,
The middle lug grooves and the middle sipes are provided alternately in the tire circumferential direction,
The middle vertical groove terminates in the middle land portion without communicating with the middle sipe and the middle lug groove , and is provided on each of the tire circumferential direction both sides of the inner end of the middle lug groove,
The shoulder land portion includes at least a plurality of shoulder lug grooves extending inward in the tire axial direction from the tread grounding end and terminating in the shoulder land portion, and shoulder longitudinal grooves extending in the tire circumferential direction.
The pneumatic tire is characterized in that the shoulder longitudinal groove terminates in the shoulder land portion without communicating with the shoulder lug groove. A pair of the center main grooves are provided on both sides of the tire equator,
2. The air according to claim 1, wherein the center land portion between the pair of center main grooves is provided with a plurality of center lug grooves having one end communicating with the center main groove and the other end terminating in the center land portion. Enter tire. The middle sipe is a cut having substantially no width;
3. The pneumatic tire according to claim 1, wherein the middle land portion is a rib continuous in a tire circumferential direction in which a lateral groove communicating with the center main groove and the shoulder main groove is not provided in addition to the middle sipe.   The pneumatic tire according to claim 1, wherein the middle vertical groove is provided on the inner side in the tire axial direction than the middle lug groove.   The pneumatic tire according to any one of claims 1 to 4, wherein the middle lug groove extends in parallel with the middle sipe.   The pneumatic tire according to any one of claims 1 to 5, wherein the middle sipe is inclined at an angle of 30 to 60 ° with respect to a tire circumferential direction.   The pneumatic tire according to any one of claims 1 to 6, wherein a shoulder auxiliary sipe extending from an inner end of the shoulder lug groove in the tire axial direction to the shoulder main groove is provided in the shoulder land portion. The pneumatic tire according to claim 2, wherein a pitch in the tire circumferential direction of the center lug groove is smaller than a pitch in the tire circumferential direction of the middle lug groove.

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