JP7135606B2 - tire - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tire having lateral grooves in the tread portion.

Patent Literature 1 below proposes a so-called mud and snow type pneumatic tire capable of exhibiting good running performance both on dry roads and on muddy ground.

JP 2014-162439 A

In the pneumatic tire of Patent Document 1, when the tire continues to run off-road on muddy or sandy ground, the lateral grooves tend to be clogged with mud and sand, and the off-road performance tends to deteriorate.

SUMMARY OF THE INVENTION The present invention has been devised in view of the problems described above, and a main object of the present invention is to provide a tire capable of sustainably exhibiting excellent off-road performance.

The present invention is a tire having a tread portion, the tread portion having a first land portion having a longitudinal edge extending in the tire circumferential direction, the first land portion comprising a plurality of first lateral grooves and a plurality of second grooves. one sipe, the first lateral groove extending axially from the longitudinal edge, the first sipe communicating with the first lateral groove at a position excluding both end portions of the first lateral groove; , extending obliquely.

In the tire of the present invention, the tread portion includes a shoulder main groove extending continuously in the tire circumferential direction at the tread end side, and a crown main groove extending continuously in the tire circumferential direction between the shoulder main groove and the tire equator. and preferably said first land portion is defined between said shoulder main groove and said crown main groove.

In the tire of the present invention, it is preferable that the longitudinal edge is located on the crown main groove side of the first land portion.

In the tire of the present invention, the first lateral grooves are inclined in a first direction with respect to the axial direction of the tire, and the first sipes are inclined in a direction opposite to the first lateral grooves with respect to the axial direction of the tire. preferably

In the tire of the present invention, it is preferable that the first sipe communicates with the first lateral groove on the longitudinal edge side of the center position of the length of the first lateral groove in the tire axial direction.

In the tire of the present invention, the first sipe has an end communicating with the first lateral groove, and the axial distance from the longitudinal edge to the communicating end is the axial distance of the first land portion. It is desirable to be at least 0.10 times the width.

In the tire of the present invention, the first land portion has a longitudinal narrow groove extending in the tire circumferential direction, and the first lateral groove and the first sipe each extend across the longitudinal narrow groove. desirable.

In the tire of the present invention, it is preferable that the first sipe is discontinued within the first land portion.

In the tire of the present invention, it is desirable that the first sipe includes a bent portion.

In the tire of the present invention, the first lateral groove preferably has a tie bar with a raised bottom.

In the tire of the present invention, the axial length of the tie bar is preferably 0.20 to 0.50 times the axial length of the first lateral groove.

The tread portion of the tire of the present invention comprises a first land portion having longitudinal edges extending in the circumferential direction of the tire. The first land portion has a plurality of first lateral grooves and a plurality of first sipes. The first lateral groove extends axially from the longitudinal edge. The first sipe communicates with the first lateral groove except for both end portions of the first lateral groove and extends obliquely.

The first sipe communicating with the first lateral groove opens and closes according to a change in ground contact pressure acting on the first land portion. This opening and closing action promotes deformation of the first lateral grooves during off-road running, and prevents clogging of the first lateral grooves with mud and sand during off-road running. In addition, since the first sipe extends obliquely from the first lateral groove, the above effect can be expected both during straight running and during turning. Furthermore, since the first sipe communicates with the first lateral groove at a position other than both end portions of the first lateral groove, it is possible to promote deformation of the first lateral groove over a wide range, thereby preventing mud and sand from entering the first lateral groove. can effectively prevent clogging.

1 is a developed view of a tread portion of a tire according to one embodiment of the present invention; FIG. FIG. 2 is an enlarged view of the first land portion of FIG. 1; FIG. 3 is a cross-sectional view taken along line AA of FIG. 2; FIG. 2 is an enlarged view of a second land portion of FIG. 1; FIG. 2 is an enlarged view of a third land portion of FIG. 1; It is an enlarged view of the 1st land part of the tire of a comparative example.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a developed view of a tread portion 2 of a tire 1 of this embodiment. The tire 1 of the present embodiment is used, for example, as a pneumatic tire for a passenger car, and preferably for an SUV intended to run on rough roads. However, the tire 1 of the present invention is not limited to such an aspect.

As shown in FIG. 1, the tread portion 2 includes, for example, a shoulder main groove 3 extending continuously in the tire circumferential direction on the tread end Te side and a crown main groove extending continuously in the tire circumferential direction on the tire equator C side. A groove 4 is provided.

In the case of a pneumatic tire, the tread end Te is applied to the tire 1 in a normal state, which is mounted on a normal rim and filled with a normal internal pressure, and is in a normal state. This is the outermost contact point in the axial direction of the tire. Unless otherwise specified, the dimensions of each part of the tire are values measured under normal conditions.

A "regular rim" is a rim defined for each tire in a standard system including the standard on which the tire is based. Then it is "Measuring Rim".

"Regular internal pressure" is the air pressure specified for each tire by each standard in the standard system including the standards on which tires are based. Maximum value described in VARIOUS COLD INFLATION PRESSURES", or "INFLATION PRESSURE" for ETRTO.

"Normal load" is the load defined for each tire by each standard in the standard system including the standard on which the tire is based. AT VARIOUS COLD INFLATION PRESSURES", and for ETRTO, it is "LOAD CAPACITY".

The shoulder main groove 3 is provided closest to the tread edge Te among the main grooves provided between the tire equator C and the tread edge Te. The shoulder main grooves 3 of this embodiment extend, for example, in a zigzag shape.

The crown main groove 4 is provided between the tire equator C and the shoulder main groove 3 . In this embodiment, two crown main grooves 4 are provided so as to sandwich the tire equator C. As shown in FIG. Only one crown main groove 4 may be provided on the tire equator C, for example. The crown main groove 4 of this embodiment extends linearly, for example.

The axial distance L1 from the tire equator C to the groove centerline of the shoulder main groove 3 is preferably, for example, 0.25 to 0.35 times the tread width TW. The axial distance L2 from the tire equator C to the groove centerline of the crown main groove 4 is preferably, for example, 0.05 to 0.10 times the tread width TW. The tread width TW is the distance in the tire axial direction from one tread end Te to the other tread end Te in the normal state.

The shoulder main groove 3 and crown main groove 4 have, for example, a groove width and a groove depth of at least 5 mm or more, preferably 6 mm or more. Specifically, it is desirable that the groove width W1 of the shoulder main groove and the groove width W2 of the crown main groove 4 are, for example, 2.5% to 6.0% of the tread width TW. In this embodiment, it is desirable that the groove width W1 of the shoulder main groove is larger than the groove width W2 of the crown main groove 4 . In this specification, unless otherwise specified, the groove width of each portion is the distance between the groove edges in the direction perpendicular to the groove center line. The groove depth of each main groove is preferably 5 to 12 mm, for example.

The tread portion 2 includes a plurality of land portions divided into the main grooves described above. Specifically, the tread portion 2 includes a first land portion 6 , a second land portion 7 and a third land portion 8 . The first land portion 6 is divided, for example, between the shoulder main groove 3 and the crown main groove 4 . However, in the present invention, the first land portion 6 is not limited to such a position. The second land portion 7 is divided, for example, between the shoulder main groove 3 and the tread edge Te. The third land portion 8 is divided between two crown main grooves 4, for example.

FIG. 2 shows an enlarged view of the first land portion 6. As shown in FIG. The first land portion 6 has a vertical edge 6e extending in the tire circumferential direction. The first land portion 6 of this embodiment has two vertical edges 6e and a tread surface therebetween.

The first land portion 6 of this embodiment has, for example, a longitudinal narrow groove 9 extending in the tire circumferential direction. The vertical narrow groove 9 is provided, for example, in the center portion of the first land portion 6 in the tire axial direction. Thus, the first land portion 6 has an inner portion 6a between the crown main groove 4 and the longitudinal narrow groove 9 and an outer portion 6b between the shoulder main groove 3 and the longitudinal narrow groove 9. . The axial width of the inner portion 6a and the axial width of the outer portion 6b are 0.40 to 0.60 times the axial width W3 of the first land portion 6, respectively.

The longitudinal grooves 9 have, for example, a groove width of less than 5 mm. The groove width of the longitudinal narrow groove 9 is preferably 1.5 to 2.5 mm, for example.

The first land portion 6 has a plurality of first lateral grooves 11 and a plurality of first sipes 21 . As used herein, "sipe" means an incision with a width of less than 1.5 mm. The width of the sipe is, for example, preferably less than 1.0 mm, more preferably 0.4-0.8 mm.

The first lateral groove 11 extends axially from the longitudinal edge 6e. In the present embodiment, the longitudinal edge 6 e with which the first lateral groove 11 communicates is located on the crown main groove 4 side of the first land portion 6 . Further, the first lateral groove 11 is interrupted within the first land portion 6, for example.

The first sipe 21 communicates with the first lateral groove 11 at positions other than both end portions of the first lateral groove 11 and extends obliquely.

The first sipe 21 communicating with the first lateral groove 11 opens and closes according to a change in ground pressure acting on the first land portion 6 . This opening and closing action promotes deformation of the first lateral grooves 11 during off-road running, and prevents clogging of the first lateral grooves 11 with mud and sand during off-road running. In addition, since the first sipe 21 obliquely extends from the first lateral groove 11, the above effect can be expected both during straight running and during turning. Furthermore, since the first sipes 21 communicate with the first lateral grooves 11 at positions other than both end portions of the first lateral grooves 11 , deformation of a wide range of the first lateral grooves 11 can be facilitated. It can effectively prevent mud and sand from clogging inside.

The first lateral groove 11 is, for example, inclined in the first direction (upward to the right in FIG. 2) with respect to the axial direction of the tire. The angle θ1 of the first lateral grooves 11 with respect to the axial direction of the tire is preferably 45° or less, for example. The angle θ1 of the first lateral groove of this embodiment is, for example, 30 to 40°. Such first lateral grooves 11 can enhance traction performance and turning performance in a well-balanced manner during off-road running.

For example, the width of the first lateral groove 11 gradually decreases toward the outside in the axial direction of the tire. It is desirable that the maximum groove width W4 of the first lateral groove 11 is larger than the groove width W2 of the crown main groove 4 (shown in FIG. 1), for example. Specifically, the groove width W4 of the first lateral groove 11 is 1.30 to 2.00 times the groove width W2 of the crown main groove 4. As shown in FIG. Such first lateral grooves 11 can suppress clogging of the interior with mud and sand during off-road driving.

The first lateral grooves 11 preferably extend across the longitudinal narrow grooves 9, for example. The axial length L3 of the first lateral groove 11 is, for example, 0.50 to 0.90 times the axial width W3 of the first land portion 6 . Such first lateral grooves 11 can improve the off-road performance while ensuring the wear resistance of the first land portion 6 .

FIG. 3 shows a cross-sectional view of the first lateral groove 11 of FIG. 2 taken along the line AA. As shown in FIG. 3, the first transverse groove 11 preferably comprises, for example, a tie bar 13 with a raised bottom. The tie bar 13 of the first lateral groove 11 of this embodiment is formed, for example, on the inner side portion 6 a of the first land portion 6 . Such a tie bar 13 enhances the rigidity of the first land portion 6 while securing the edge component of the first lateral groove 11, thereby enhancing the steering stability on a dry road surface.

The tie bar depth d2 from the contact surface of the first land portion 6 to the outer surface of the tie bar 13 is preferably 1.5 mm or more smaller than the maximum depth d1 of the first lateral groove 11. Specifically, the tie bar depth d2 is preferably 0.70 to 0.90 times the maximum depth d1 of the first lateral groove 11. Such a tie bar 13 enhances off-road performance and steering stability on a dry road in a well-balanced manner.

From a similar point of view, the axial length L4 of the tie bar 13 is, for example, 0.20 to 0.50 times the axial length L3 of the first lateral groove 11 (shown in FIG. 2). desirable.

As shown in FIG. 2 , the first sipe 21 communicates with the first lateral groove 11 at the inner portion 6a of the first land portion 6, for example. The first sipe 21 extends, for example, from the first land portion 6 obliquely across the vertical thin groove 9 . Moreover, the first sipe 21 is interrupted within the first land portion 6 . In a more desirable aspect, the first sipe 21 is discontinued within the outer portion 6b of the first land portion 6 .

For example, the first sipe 21 is desirably inclined in the opposite direction to the first lateral groove 11 with respect to the axial direction of the tire. Such a first sipe 21 provides a grip in a direction different from that of the first lateral groove 11 by its edge.

The first sipe 21 of the present embodiment includes, for example, a steep slope portion 21a and a gentle slope portion 21b. The steeply inclined portion 21a, for example, extends from the first lateral groove 11 and is inclined at an angle of 40 to 50° with respect to the axial direction of the tire. The gently sloping portion 21b continues to the axially outer side of the steeply sloping portion 21a. For example, the gently sloping portion 21b is slanted at an angle smaller than that of the steeply sloping portion 21a with respect to the axial direction of the tire. The angle of the gently sloping portion 21b with respect to the axial direction of the tire is, for example, 5 to 15°. Further, in the first sipe 21 of the present embodiment, the gently sloping portion 21b crosses the vertical thin groove 9 . Such a first sipe 21 can make the steering response linear when the centroid of the ground contact surface moves outward in the axial direction of the tire during turning, which in turn improves steering stability on dry road surfaces. can be done.

The first sipe 21 includes a bent portion by having a steep slope portion 21a and a gentle slope portion 21b. Further, the first sipe 21 is bent so as to protrude on one side in the tire circumferential direction (downward in FIG. 2). Also, the first sipe 21 is bent at an obtuse angle. Such a first sipe 21 can improve off-road performance while maintaining wear resistance and steering stability on a dry road surface.

The first sipe 21 has a communicating end 21 e with the first lateral groove 11 . The communicating end 21e of the first sipe 21 is desirably arranged in the inner portion 6a of the first land portion 6, for example. Also, the first sipe 21 preferably communicates with the first lateral groove 11 on the side of the longitudinal edge 6 e contacting the crown main groove 4 with respect to the center position of the axial length of the first lateral groove 11 . Thereby, the length of the first sipe 21 is ensured.

The axial distance L5 from the longitudinal edge 6e in contact with the crown main groove 4 to the communicating end 21e is preferably 0.10 times or more the axial width W3 of the first land portion 6. As shown in FIG. Specifically, the distance L5 is preferably 0.10 to 0.20 times the width W3 of the first land portion 6. As shown in FIG. As a result, a sufficient distance is secured between the communicating end 21e and the vertical edge 6e, and the abrasion resistance of the first land portion 6 and the steering stability on dry road surfaces are enhanced.

In a more desirable aspect, it is desirable that the communicating end 21e of the first sipe 21 overlaps the area of the tie bar 13 of the first lateral groove 11 virtually extending outward in the tire radial direction. Thereby, the wear resistance of the first land portion 6 is further enhanced.

A plurality of second lateral grooves 12 are provided in the first land portion 6 of the present embodiment. For example, the second lateral grooves 12 and the first lateral grooves 11 described above are provided alternately in the tire circumferential direction.

The second lateral groove 12 extends from the crown main groove 4 to the shoulder main groove 3, for example. Such second lateral grooves 12 serve to enhance off-road performance.

The second lateral grooves 12 are, for example, inclined with respect to the tire axial direction. The second lateral grooves 12 of this embodiment are inclined in the same direction as the first lateral grooves 11 . The angle of the second lateral grooves 12 with respect to the axial direction of the tire is, for example, 45° or less. Specifically, the angle of the second lateral grooves 12 with respect to the axial direction of the tire is preferably 30 to 40 degrees.

The second lateral groove 12 includes an inner groove portion 12 a arranged on the inner portion 6 a of the first land portion 6 and an outer groove portion 12 b arranged on the outer portion 6 b of the first land portion 6 . The outer groove portion 12b is preferably inclined with respect to the axial direction of the tire at a smaller angle than the inner groove portion 12a. Such second lateral grooves 12 can provide a linear steering response when turning, and can improve steering stability on a dry road surface.

In a more desirable aspect, for example, the width of the inner groove portion 12a gradually decreases toward the outside in the tire axial direction. The outer groove portion 12b extends, for example, with a constant groove width.

The second transverse groove 12 preferably comprises, for example, a tie bar 14 with a raised bottom. The tie bar 14 of the second lateral groove 12 has substantially the same structure as the tie bar 13 of the first lateral groove 11, for example. Therefore, the configuration of the tie bar 13 of the first lateral groove 11 described above can be applied to the tie bar 14 of the second lateral groove 12 .

For example, a plurality of first short grooves 16 and a plurality of second short grooves 17 are provided in the first land portion 6 of the present embodiment. The first short grooves 16 and the second short grooves 17 increase the edge component of the first land portion 6 and serve to exhibit excellent off-road performance.

The first short groove 16 , for example, extends axially outward from the longitudinal edge 6 e contacting the crown main groove 4 and discontinues within the inner portion 6 a of the first land portion 6 . The first short groove 16 of this embodiment is provided between the first lateral groove 11 and the inner groove portion 12 a of the second lateral groove 12 . The first short grooves 16 are preferably inclined in the same direction as the first lateral grooves 11, for example.

The first short groove 16 is desirably discontinued, for example, outside the communicating end 21e of the first sipe 21 in the axial direction of the tire. In this embodiment, the discontinuous end 16a of the first short groove 16 overlaps a region obtained by virtually extending the tie bar 13 provided in the first lateral groove 11 in the tire circumferential direction. As a result, the wear resistance of the first land portion 6 and the steering stability on dry road surfaces can be improved.

The second short groove 17 , for example, extends axially inward from the longitudinal edge 6 e contacting the shoulder main groove 3 and discontinues within the outer portion 6 b of the first land portion 6 . In this embodiment, two second short grooves 17 are provided between two second lateral grooves 12 adjacent in the tire circumferential direction.

The two second short grooves 17 are, for example, inclined in opposite directions with respect to the axial direction of the tire. Thereby, uneven wear of the first land portion 6 is suppressed.

The interrupted end 17a of the second short groove 17 is desirably positioned, for example, further outward than the interrupted end 11a of the first lateral groove 11 in the axial direction of the tire. Such second short grooves 17 can maintain the rigidity of the first land portion 6 and improve steering stability on dry road surfaces.

A second sipe 22, a third sipe 23 and a fourth sipe 24 are provided in the first land portion 6 of the present embodiment.

For example, the second sipe 22 communicates with the second lateral groove 12 at a position excluding both end portions of the second lateral groove 12 and extends obliquely.

The second sipe 22 preferably communicates with the second lateral groove 12 , for example, axially inward of the tie bar 14 of the second lateral groove 12 . Moreover, it is desirable that the second sipe 22 is discontinued axially inward of the discontinuous end of the first sipe 21 . In a more desirable aspect, the second sipe 22 is discontinued axially inward of the discontinuous end 11 a of the first lateral groove 11 .

The second sipe 22 has substantially the same configuration as the first sipe 21 except for the configuration described above. Therefore, the configuration of the first sipe 21 described above can be applied to the second sipe 22 .

The third sipe 23 is provided, for example, on the outer portion 6b of the first land portion 6 . The third sipe 23 of this embodiment extends, for example, from the vertical edge 6e in contact with the shoulder main groove 3 to the vertical thin groove 9. As shown in FIG.

The third sipe 23 is, for example, convex and bent in the opposite direction (upward in FIG. 2) to the first sipe 21 and the second sipe 22 . Such a third sipe 23 helps suppress uneven wear of the first land portion 6 .

The fourth sipe 24 extends from the discontinuous end 11a of the first lateral groove 11 to the shoulder main groove 3, for example. The fourth sipe 24 is desirably bent in the same direction as the third sipe 23, for example.

FIG. 4 shows an enlarged view of the second land portion 7. As shown in FIG. As shown in FIG. 4, the second land portion 7 comprises, for example, a plurality of compound lateral grooves 30. As shown in FIG.

The compound lateral groove 30 includes, for example, a first groove portion 31, a second groove portion 32 and a third groove portion 33. As shown in FIG. For example, the first groove portion 31 continues to the shoulder main groove 3 and extends in the tire axial direction with a constant width. For example, the second groove portion 32 continues to the axially outer side of the first grooved portion 31 and gradually increases in groove width outward in the tire axial direction. For example, the third groove portion 33 continues to the axially outer side of the second groove portion 32 and extends in the tire axial direction with a constant groove width. Such composite lateral grooves 30 improve off-road performance and steering stability on dry road surfaces in a well-balanced manner.

The third groove portion 33 is desirably larger than, for example, the maximum groove width of the first lateral grooves 11 . Such a third groove 33 provides a great grip especially on muddy ground.

It is desirable that the compound lateral grooves 30 are inclined, for example, in the opposite direction to the first lateral grooves 11 with respect to the axial direction of the tire. Since such a compound lateral groove 30 can provide a frictional force in a direction different from that of the first lateral groove 11, the steering response is linear in various turning states.

The second land portion 7 includes, for example, a plurality of blocks 35 partitioned into a plurality of composite lateral grooves 30 . The block 35 is provided with, for example, one semi-open sipe 36 and one closed sipe 37 .

The semi-open sipe 36 extends, for example, from the shoulder main groove 3 and is discontinued within the block 35 . The semi-open sipe 36 of the present embodiment is interrupted, for example, outside the second groove portion 32 of the composite lateral groove 30 in the tire axial direction. Such a semi-open sipe 36 can provide an edge component while maintaining the rigidity of the second land portion 7 .

The closed sipe 37 is, for example, interrupted at both ends within the block 35 . The closed sipe 37 of this embodiment has, for example, one end 37a located axially inside the second groove portion 32 of the composite lateral groove 30, and the other end 37b located axially outside the second groove portion 32. there is In addition, the other end 37b of the closed sipe 37 is axially outside the semi-open sipe 36 with respect to the discontinuous end.

It is desirable that each of the semi-open sipe 36 and the closed sipe 37 is bent at least partially. This increases the rigidity of the second land portion 7 when the sipe walls facing each other of the sipes come into contact with each other. Such action helps to improve steering stability on dry road surfaces.

An enlarged view of the third land portion 8 is shown in FIG. As shown in FIG. 5, the third land portion 8 is configured, for example, as a rib continuously extending in the tire circumferential direction.

The third land portion 8 of this embodiment includes, for example, a plurality of inclined short grooves 41 and a plurality of reverse inclined sipes 42 .

The inclined short groove 41 , for example, extends obliquely from the crown main groove 4 and discontinues within the third land portion 8 . The inclined short grooves 41 of the present embodiment are preferably inclined in the same direction as the first lateral grooves 11 provided in the first land portion 6, for example. Such inclined short grooves 41 cooperate with the first lateral grooves 11 to improve off-road performance.

It is desirable that the short inclined groove 41 is interrupted without crossing the tire equator C, for example. Such short inclined grooves 41 maintain the rigidity of the third land portion 8 and enhance off-road performance and steering stability on dry road surfaces in a well-balanced manner.

It is desirable that the groove width of the inclined short groove 41 gradually decreases toward the tire equator C side, for example. Moreover, it is desirable that the maximum groove width of the inclined short grooves 41 is smaller than the maximum groove width of the first lateral grooves 11 . Such short inclined grooves 41 help to improve the wear resistance of the third land portion 8 .

As shown in FIG. 1, the end of the inclined short groove 41 of the present embodiment on the crown main groove 4 side is, for example, the end of the first lateral groove 11 or the second lateral groove 12 on the crown main groove 4 side of the tire axis. It is desirable to overlap the region that virtually extends along the direction. Such an inclined short groove 41, for example, provides a high reaction force by compacting and shearing mud together with the first lateral groove 11 or the second lateral groove 12 when traveling on a muddy ground.

As shown in FIG. 5 , the reverse inclined sipe 42 extends, for example, from the crown main groove 4 while being inclined in a direction opposite to the inclined short groove 41 and is discontinued within the third land portion 8 . The reverse sloping sipes 42 are preferably discontinuous without crossing the tire equator C. In addition, the reverse inclined sipes 42 and the inclined short grooves 41 are provided alternately in the tire circumferential direction. Such reverse inclined sipes 42 are useful for suppressing uneven wear of the third land portion 8 .

As shown in FIG. 1 , the end portion of the reverse inclined sipe 42 on the crown main groove 4 side corresponds to, for example, the end portion of the first short groove 16 provided in the first land portion 6 on the crown main groove 4 side of the tire. Desirably, it overlaps the area that virtually extends along the axial direction. Such a reverse inclined sipe 42 facilitates the opening and closing of the first short groove 16 when ground pressure is applied, and effectively suppresses clogging of the first short groove 16 with mud or sand.

Although the tire of one embodiment 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 in various ways.

A pneumatic tire of size 225/60R18 having the basic pattern of FIG. 1 was prototyped. As a comparative example, as shown in FIG. 6, a pneumatic tire was experimentally produced in which the first lateral grooves b provided in the first land portions a did not communicate with the first sipes. The tread portion of the tire of the comparative example has substantially the same pattern as that shown in FIG. 1, except for the above configuration. Each test tire was tested for off-road performance and steering stability on dry roads. Common specifications and test methods for each test tire are as follows.
Mounting rim: 18 x 7.0J
Tire internal pressure: 230KPa
Test vehicle: 2000cc displacement, 4WD vehicle Tire mounting position: All wheels

<Off-road performance>
The driving performance (including the durability of the grip) when the test vehicle was driven on off-road including muddy and sandy terrain was evaluated by the driver's senses. The results are scored with the comparative example being 100, and the larger the number, the better the off-road performance.

<Driving stability on dry road surface>
When the test vehicle was run on a dry road surface, the steering stability was evaluated by the driver's sensory perception. The results are scored with the comparative example being 100, and the larger the number, the better the steering stability on a dry road surface.
The results of the tests are shown in Table 1.

As a result of the test, it was confirmed that the tire of Example exhibited excellent off-road performance continuously. It was also confirmed that the tires of Examples maintained steering stability on dry road surfaces.

2 tread portion 6 first land portion 6e longitudinal edge 11 first lateral groove 21 first sipe

Claims (10)

A tire having a tread portion,
The tread portion includes a first land portion having a longitudinal edge extending in the tire circumferential direction,
The first land portion includes a plurality of first lateral grooves and a plurality of first sipes,
the first lateral groove extends axially from the longitudinal edge and is discontinued within the first land portion;
The first sipe communicates with the first lateral groove at a position excluding both end portions of the first lateral groove and extends obliquely ,
The first land portion further includes a longitudinal narrow groove extending in the tire circumferential direction,
The first lateral groove and the first sipe each extend across the longitudinal narrow groove,
tire. The tread portion includes a shoulder main groove extending continuously in the tire circumferential direction at the tread end side, and a crown main groove extending continuously in the tire circumferential direction between the shoulder main groove and the tire equator,
2. The tire according to claim 1, wherein said first land portion is divided between said shoulder main groove and said crown main groove. 3. The tire of claim 2, wherein the longitudinal edge is located on the crown main groove side of the first land portion. the first lateral grooves are inclined in a first direction with respect to the axial direction of the tire;
The tire according to any one of claims 1 to 3, wherein said first sipe is inclined in a direction opposite to said first lateral groove with respect to the tire axial direction. The tire according to any one of claims 1 to 4, wherein the first sipe communicates with the first lateral groove on the longitudinal edge side of the center position of the length of the first lateral groove in the tire axial direction. The first sipe has an end communicating with the first lateral groove,
The tire according to any one of claims 1 to 5, wherein the axial distance from the longitudinal edge to the communicating end is 0.10 times or more the axial width of the first land portion. 2. The tire of claim 1, wherein said first sipe is discontinuous within said first land portion. 8. The tire of any one of claims 1-7, wherein the first sipe includes a bent portion. 9. A tire according to any preceding claim, wherein the first lateral groove comprises a tie bar with a raised bottom. The tire according to claim 9, wherein the axial length of the tie bar is 0.20 to 0.50 times the axial length of the first lateral groove.

Images