JP7131368B2 - tire - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tire, and more particularly to a tire provided with sipes in a middle land portion.

Patent Literature 1 listed below describes a pneumatic tire in which an axial sipe is provided in a middle land portion. In the pneumatic tire of Patent Document 1, the axial sipes are expected to maintain the rigidity of the middle land portion and improve drainage performance.

JP 2014-205420 A

However, the pneumatic tire of Patent Document 1 has room for improvement in terms of steering stability, especially responsiveness when a slip angle is given during running (hereinafter referred to as "initial responsiveness"). On the other hand, if the land portion of the tread portion is made highly rigid in order to improve steering stability, there is a problem that uneven wear occurs in the land portion.

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 exhibiting excellent steering stability without impairing wear resistance.

The present invention is a tire having a tread portion, wherein the tread portion includes a crown main groove extending continuously in the tire circumferential direction, and a tire circumferentially continuous portion between the crown main groove and a first tread end. a first shoulder main groove extending in a straight line; a first middle land portion partitioned between the crown main groove and the first shoulder main groove; a second middle land portion; and a first shoulder land portion adjacent to the first middle land portion via the first shoulder main groove, wherein the first middle land portion includes the first middle land portion. a plurality of first transverse sipes that completely traverse the second middle land portion, and a plurality of second transverse sipes that completely traverse the second middle land portion; The shoulder land portion is provided with a plurality of first shoulder sipes extending axially outward from the first shoulder main groove. It is arranged so as to be smoothly continuous with each of the first shoulder sipes, and is arranged so as not to be smoothly continuous with each of the second transverse sipes via the crown main groove.

In the tire of the present invention, the region of the first transverse sipe that extends along the length direction toward the first shoulder land portion is aligned with the end of the first shoulder sipe on the first shoulder main groove side. Duplicate is preferred.

In the tire of the present invention, a first region in which the first transverse sipe extends in the longitudinal direction toward the second middle land portion, and a first region in which the second transverse sipe extends in the longitudinal direction in the first region. It is desirable that the second region extending toward the middle land portion and the second region do not overlap each other in the crown main groove.

In the tire of the present invention, it is preferable that the minimum circumferential distance between the first region and the second region in the crown main groove is 3.0 to 6.0 mm.

In the tire of the present invention, it is desirable that at least one of the first transverse sipes has a raised shallow bottom portion at positions other than both ends in the tire axial direction.

In the tire of the present invention, the first middle land portion is provided with a plurality of first non-crossing sipes extending from the crown main groove and interrupted within the first middle land portion. is preferably provided with a plurality of second non-transverse sipes extending from said crown main groove and interrupted within said second middle land portion.

In the tire of the present invention, it is desirable that each of the first non-transverse sipes is not smoothly continuous with each of the second non-transverse sipes via the crown main groove.

In the tire of the present invention, a third region in which the first non-crossing sipe extends along the length direction toward the second middle land portion, and a third region extending the second non-crossing sipe along the length direction It is desirable that the fourth region extending toward the first middle land portion and the fourth region do not overlap each other within the crown main groove.

In the tire of the present invention, it is preferable that the minimum circumferential distance between the third region and the fourth region in the crown main groove is 1.0 to 2.0 mm.

In the tire of the present invention, a chamfered portion is provided in a communicating portion between the crown main groove and the first non-transverse sipe, and the chamfered portion is a tread surface of the first middle land portion and a groove wall of the crown main groove. and a sloping surface contiguous with each of the sipe walls of said first non-transverse sipe.

In the tire of the present invention, the first shoulder land portion is provided with a second shoulder sipe extending in the tire axial direction, and the axially inner end of the second shoulder sipe is interrupted within the first shoulder land portion. , It is desirable that the region extending along the length of the first non-transverse sipe toward the first shoulder land portion overlaps the inner end of the second shoulder sipe.

In the tire of the present invention, the first middle land portion is provided with a plurality of first transverse sipes that completely traverse the first middle land portion. The second middle land portion is provided with a plurality of second transverse sipes that completely cross the second middle land portion, and the first shoulder land portion is provided with a plurality of sipes extending axially outward from the first shoulder main groove. is provided with a first shoulder sipe. Each of the first transverse sipes is arranged so as to be smoothly continuous with each of the first shoulder sipes via the first shoulder main groove, and is arranged to smoothly connect with each of the first shoulder sipes via the crown main groove. Disposed smoothly and out of continuance with each of the transverse sipes.

In order to improve the initial responsiveness of the tire during cornering, it is important to increase the torsional rigidity of the tread portion when the tire is given a slip angle. According to experiments by the inventors, when the first transverse sipe, the second transverse sipe and the first shoulder sipe are arranged in relation to each other as described above, when the slip angle is given, the first It has been found that the torsional stiffness over the second middle land portion is optimized, which in turn improves the initial response.

Further, the first middle land portion and the second middle land portion, which are subjected to a large ground contact pressure during straight running, are provided with a first crossing sipe and a second crossing sipe, respectively. These first transverse sipe and second transverse sipe allow deformation of each land portion at the time of ground contact without lowering the rigidity of the first middle land portion and the second middle land portion. Therefore, the tire of the present invention can reduce the slippage of the first middle land portion and the second middle land portion on the road surface while improving the initial responsiveness, and can also prevent deterioration of wear resistance.

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 a first middle land portion, a second middle land portion, and a first shoulder land portion in FIG. 1; 2. (a) is a cross-sectional view taken along the line AA of FIG. 2, and (b) is a cross-sectional view taken along the line BB of FIG. 3 is an enlarged perspective view of the first non-transverse sipe of FIG. 2; FIG. 4 is a developed view of a tread portion of a tire of Comparative Example 1. FIG.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows a developed view of a tread portion 2 of a tire 1 of this embodiment. The tire 1 of the present embodiment is suitably used as, for example, a pneumatic tire for passenger cars. However, the tire 1 of the present invention is not limited to such a mode of use.

As shown in FIG. 1, the tread portion 2 of the tire 1 includes one crown main groove 3 extending continuously in the tire circumferential direction, and a tire circumferential groove between the crown main groove 3 and the first tread end Te1. A first shoulder main groove 4 continuously extending in the tire circumferential direction and a second shoulder main groove 5 continuously extending in the tire circumferential direction between the crown main groove 3 and the second tread edge Te2 are provided.

The first tread end Te1 and the second tread end Te2 are mounted on a regular rim (not shown), are filled with regular internal pressure, and are in a regular state with no load. This is the outermost grounding position in the axial direction of the tire when it is grounded on a flat surface at an angle of 0°.

A "regular rim" is a rim defined for each tire in a standard system that includes standards on which tires are based. For ETRTO, 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 crown main groove 3 of this embodiment is arranged on the tire equator C, for example.

The axial distance L1 from the tire equator C to the groove centerline of the first shoulder main groove 4 or the second shoulder main groove 5 is preferably, for example, 0.20 to 0.30 times the tread width TW. . The tread width TW is the axial distance of the tire from the first tread end Te1 to the second tread end Te2 in the normal state.

It is desirable that the groove width W1 of each main groove is, for example, 4 to 7% of the tread width TW. The groove depth of each main groove is preferably 5 to 10 mm, for example.

The tread portion 2 is provided with a crown main groove 3, a first shoulder main groove 4 and a second shoulder main groove 5, thereby forming a first middle land portion 6, a second middle land portion 7 and a first shoulder land portion. A portion 8 and a second shoulder land portion 9 are separated.

The first middle land portion 6 is divided between the crown main groove 3 and the first shoulder main groove 4 . The second middle land portion 7 is divided between the crown main groove 3 and the second shoulder main groove 5 . The second middle land portion 7 is adjacent to the first middle land portion 6 with the crown main groove 3 interposed therebetween.

The first shoulder land portion 8 is divided between the first shoulder main groove 4 and the first tread edge Te1. The first shoulder land portion 8 is adjacent to the first middle land portion 6 via the first shoulder main groove 4 . The second shoulder land portion 9 is divided between the second shoulder main groove 5 and the second tread edge Te2. The second shoulder land portion 9 is adjacent to the second middle land portion 7 via the second shoulder main groove 5 .

The tread portion 2 of this embodiment has a substantially point-symmetrical tread pattern. Therefore, the configuration of the first middle land portion 6 described below can be applied to the second middle land portion 7 . Also, the configuration of the first shoulder land portion 8 can be applied to the second shoulder land portion 9 .

FIG. 2 shows an enlarged view of the first middle land portion 6, the second middle land portion 7 and the first shoulder land portion 8. As shown in FIG. As shown in FIG. 2 , the first middle land portion 6 is provided with a plurality of first transverse sipes 11 that completely traverse the first middle land portion 6 . The second middle land portion 7 is provided with a plurality of second transverse sipes 12 that completely traverse the second middle land portion 7 . The first shoulder land portion 8 is provided with a plurality of first shoulder sipes 31 extending axially outward from the first shoulder main groove 4 . In this specification, "sipe" means a cut with a width of less than 2.0 mm.

Each of the first transverse sipes 11 is arranged so as to be smoothly continuous with each of the first shoulder sipes 31 via the first shoulder main grooves 4 . Moreover, each of the first transverse sipes 11 is arranged so as not to be smoothly continuous with each of the second transverse sipes 12 via the crown main groove 3 .

In this specification, "one sipe is smoothly continuous with the other sipe through the main groove" means that one sipe is extended along its longitudinal direction and the other sipe is It means that the minimum circumferential distance of the tire in the main groove is less than 1.0 mm, with respect to the area extending along the longitudinal direction. In addition, when the sipe is bent, the region extends while maintaining the curvature at the end of the sipe on the main groove side.

In order to improve the initial responsiveness of a pneumatic tire during cornering, it is important to increase the torsional rigidity of the tread portion when the tire is given a slip angle. According to experiments by the inventors, when the first transverse sipe 11, the second transverse sipe 12, and the first shoulder sipe 31 are arranged in relation to each other as described above, when a slip angle is given, the first shoulder land It was found that the torsional stiffness from the portion 8 to the second middle land portion 7 was optimized, and the initial response was improved.

A first crossing sipe 11 and a second crossing sipe 12 are provided in the first middle land portion 6 and the second middle land portion 7, respectively, on which a large ground contact pressure acts during straight traveling. These first transverse sipe 11 and second transverse sipe 12 allow deformation of the respective land portions at ground contact without lowering the rigidity of the first middle land portion 6 and the second middle land portion 7 . Therefore, the pneumatic tire of the present invention can improve the initial response, reduce the slippage of the first middle land portion 6 and the second middle land portion 7 on the road surface, and prevent deterioration of wear resistance.

The tire circumference in the first shoulder main groove 4 is defined by a region 17a where the first transverse sipe 11 extends toward the first shoulder land portion 8 and a region 17b where the first shoulder sipe 31 extends toward the first middle land portion 6. The minimum directional separation (hereinafter sometimes referred to as the first minimum separation) is preferably less than 0.5 mm. In this embodiment, the regions 17a and 17b overlap (that is, the first minimum distance is 0). In a more desirable embodiment, the region 17a of the first transverse sipe 11 extending along the longitudinal direction toward the first shoulder land portion 8 is aligned with the end portion of the first shoulder sipe 31 on the first shoulder main groove 4 side. Duplicate. Such arrangement of the sipes facilitates the movement of the first middle land portion 6 and the first shoulder land portion 8 together, and is useful for further enhancing the initial responsiveness.

A first region 21 in which the first transverse sipe 11 extends along the length direction toward the second middle land portion 7 side, and a second transverse sipe 12 extends along the length direction toward the first middle land portion 6 side. The extended second region 22 does not overlap with each other within the crown main groove 3 . In the crown main groove 3, the minimum distance between the first region 21 and the second region 22 in the tire circumferential direction (hereinafter sometimes referred to as the second minimum distance) is at least 1.0 mm or more. As a desirable aspect, the second minimum separation distance in this embodiment is 3.0 to 6.0 mm. Such an arrangement of sipes helps suppress uneven wear of the first middle land portion 6 and the second middle land portion 7 .

The first transverse sipe 11 , for example, extends linearly from the crown main groove 3 to the first shoulder main groove 4 . Further, the first transverse sipe 11 is, for example, inclined in one direction with respect to the tire axial direction. The angle of the first transverse sipe 11 with respect to the axial direction of the tire is preferably 15 to 35 degrees, for example.

FIG. 3(a) shows a cross-sectional view of the first transverse sipe 11 of FIG. 2 taken along the line AA. As shown in FIG. 3( a ), the first transverse sipe 11 is arranged, for example, in an opening 28 opening at the tread surface of the first middle land portion 6 and inside the opening 28 in the tire radial direction, and and a narrow portion 29 having a width smaller than that of the opening 28 . A width W4 of the opening 28 is, for example, 1.0 to 1.8 mm. A width W5 of the narrow portion 29 is, for example, 0.6 to 1.0 mm. Such a first transverse sipe 11 can be expected to improve wet performance while maintaining the rigidity of the first middle land portion 6 .

FIG. 3(b) shows a cross-sectional view of the first transverse sipe 11 of FIG. 2 taken along the line BB. As shown in FIG. 3(b), the first transverse sipe 11 preferably has a shallow portion 27 with a raised bottom, for example. The shallow bottom portion 27 is desirably raised, for example, at positions other than both ends in the axial direction of the tire. The shallow bottom portion 27 crosses the center of the first middle land portion 6 in the tire axial direction. Such a shallow bottom portion 27 enhances initial response and wear resistance in a well-balanced manner.

In order to further enhance the above effect, the depth d2 of the shallow portion 27 is preferably 0.45 to 0.65 times the maximum depth d1 of the first transverse sipe 11, for example. The axial length L5 of the shallow bottom portion 27 is preferably, for example, 0.55 to 0.70 times the axial width W2 of the first middle land portion 6 (shown in FIG. 2).

Each configuration of the first transverse sipe 11 described above can be applied to the second transverse sipe 12 .

As shown in FIG. 2 , in the present embodiment, the first middle land portion 6 is provided with a plurality of first non-crossing sipes 13 extending from the crown main groove 3 and interrupted within the first middle land portion 6 . there is In the first middle land portion 6, the first crossing sipes 11 and the first non-crossing sipes 13 are alternately provided in the tire circumferential direction. In a more desirable aspect, the first crossing sipes 11 and the first non-crossing sipes 13 are arranged at substantially equal intervals in the tire circumferential direction.

Similarly, the second middle land portion 7 is provided with a plurality of second non-transverse sipes 14 extending from the crown main groove 3 and interrupted within the second middle land portion 7 . In the second middle land portion 7, the second crossing sipes 12 and the second non-crossing sipes 14 are alternately provided in the tire circumferential direction. In a more desirable aspect, the second transverse sipes 12 and the second non- transverse sipes 14 are arranged at substantially equal intervals in the tire circumferential direction.

Preferably, each of the first non-transverse sipes 13 is not smoothly continuous with each of the second non-transverse sipes 14 through the crown main groove 3 . Specifically, the third region 23 is formed by extending the first non-crossing sipe 13 along its length direction toward the second middle land portion 7 side, and the second non-crossing sipe 14 is extended along its length direction to the third region 23 . The fourth region 24 extending toward the first middle land portion 6 side does not overlap with each other within the crown main groove 3 . Such first non-crossing sipe 13 and second non-crossing sipe 14 can further suppress uneven wear of the first middle land portion 6 and the second middle land portion 7 .

In the crown main groove 3, the minimum distance between the third region 23 and the fourth region 24 in the tire circumferential direction (hereinafter sometimes referred to as the third minimum distance) is, for example, 1.0 to 6.0 mm. and more preferably 1.0 to 2.0 mm. Such first non-crossing sipe 13 and second non-crossing sipe 14 can improve initial response and wear resistance in a well-balanced manner.

An enlarged perspective view of the first non-transverse sipe 13 is shown in FIG. As shown in FIG. 4, a chamfered portion 25 is preferably provided in the communication portion 13a between the crown main groove 3 and the first non-transverse sipe 13. As shown in FIG. The chamfered portion 25 has an inclined surface 25 a that is continuous with the tread surface of the first middle land portion 6 , the groove wall of the crown main groove 3 and the sipe wall of the first non-transverse sipe 13 .

Since the first middle land portion 6 of the present embodiment is provided with the first crossing sipe 11 and the first non-crossing sipe 13, the crown main groove 3 side is relatively easily deformed. Therefore, when a large ground contact pressure acts on the first middle land portion 6 or when a slip angle is applied to the tire, a portion of the outer surface of the chamfered portion 25 can be brought into contact with the ground. The substantial contact area of the portion 6 is increased. Therefore, initial responsiveness during turning is enhanced, and excellent steering stability can be expected.

In addition, since the first middle land portion 6 of the present embodiment is provided with the chamfered portion 25, it is possible to reduce the hammering sound when the communication portion 13a touches the ground, thereby improving the noise performance.

In a desirable mode, the inclined surface 25a of the chamfered portion 25 is configured as a curved surface. Further, in the present embodiment, the inclined surface 25a is a curved surface that protrudes outward from the first middle land portion 6. As shown in FIG. Such a chamfered portion 25 can smoothly bring the inclined surface into contact with the ground when the ground contact pressure acting on the first middle land portion 6 increases, and can suppress uneven wear around the chamfered portion 25 .

The maximum depth of the chamfer 25 is, for example, 2.0-4.0 mm, preferably 2.5-3.5 mm.

As shown in FIG. 2, in a plan view of the tread, the tread surface side edge 26 between the inclined surface 25a and the tread surface of the first middle land portion 6 is preferably curved, and more preferably arcuate.

For example, the chamfered portion 25 is preferably arranged at a corner portion where the angle between the groove edge 3e of the crown main groove 3 and the edge 13e of the first non-transverse sipe 13 is an obtuse angle. That is, in a tread plan view, the angle between the edge 13e of the first non-transverse sipe 13 connected to the tread side edge 26 and the groove edge 3e of the crown main groove 3 connected to the tread side edge 26 is an obtuse angle. Such a chamfered portion 25 has a larger inclined surface than that provided at a corner portion with an acute angle, and can further exhibit the above-described effects.

In a tread plan view, the axial length L6 of the chamfered portion 25 is, for example, preferably 0.30 times or more, more preferably 0.35 times the axial length L2 of the first non-crossing sipe 13. or more, preferably 0.45 times or less, more preferably 0.40 times or less. Such a chamfered portion 25 can improve steering stability and noise performance in a well-balanced manner.

From the same point of view, the length of the chamfered portion 25 along the groove edge 3e of the crown main groove 3 is preferably 0.90 to 1.50 times the length L6 of the chamfered portion 25 in the axial direction of the tire.

In the present embodiment, the chamfered portion 25 continuous with the first non-crossing sipe 13 is provided on one side of the first non-crossing sipe 13 in the tire circumferential direction, and the chamfering portion 25 continuous with the second non-crossing sipe 14 is located at the second non-crossing sipe 13 . It is provided on the other side of the non-crossing sipe 14 in the tire circumferential direction. Further, a region obtained by extending the chamfered portion 25 continuous with the first non-crossing sipe 13 along the length direction of the first non-crossing sipe 13 is the chamfering portion 25 continuous with the second non-crossing sipe 14 . does not overlap with regions extending along the length of Such an arrangement of the chamfered portion 25 can further suppress uneven wear of the first middle land portion 6 and the second middle land portion 7 .

The above-described chamfered portion 25 is provided only on the first non-crossing sipe 13 and not provided on the first crossing sipe 11 . As a result, it is possible to prevent the chamfered portion from excessively reducing the contact area during normal running.

The first non-transverse sipe 13 is, for example, inclined with respect to the tire axial direction. The first non-transverse sipe 13 is slanted in the same direction as the first transverse sipe 11, for example. The angle of the first non-transverse sipe 13 with respect to the tire axial direction is, for example, 15 to 35 degrees. As a more desirable aspect, in this embodiment, the first crossing sipe 11 and the first non-crossing sipe 13 are arranged parallel to each other.

The axial length L2 of the first non-crossing sipe 13 is, for example, preferably 0.40 to 0.60 times the axial width W2 of the first middle land portion 6, and more preferably 0.40 to 0.60 times. 51 to 0.55 times.

The interrupted end 13b in the first middle land portion 6 of the first non-crossing sipe 13 is arranged near the central portion of the block piece 6a divided between the two first crossing sipes 11, for example. desirable. Specifically, the discontinuous end 13b of the first non-crossing sipe 13 is preferably provided at a position where the distance from the centroid of the tread surface of the block piece 6a is less than 5 mm. In a further preferred embodiment, the discontinuous end 13b of the first non-transverse sipe 13 is arranged on the centroid of the tread surface of the block piece 6a. Such a first non-crossing sipe 13 can suppress uneven wear around its interrupted end 13b.

Each configuration of the first non-crossing sipe 13 described above can be applied to the second non-crossing sipe 14 .

The first shoulder land portion 8 is provided with a first shoulder lateral groove 30 and a second shoulder sipe 32 in addition to the first shoulder sipe 31 described above. The first shoulder lateral grooves 30 and the second shoulder sipes 32 are alternately provided in the tire circumferential direction.

The first shoulder lateral groove 30 , for example, extends axially inward from the first tread end Te<b>1 and discontinues within the first shoulder land portion 8 . The first shoulder sipe 31 extends from the first shoulder main groove 4 to the inner end 30i of the first shoulder lateral groove 30. As shown in FIG.

The axial length L3 of the first shoulder lateral groove 30 is preferably 0.75 to 0.79 times the axial width W3 of the first shoulder land portion 8, for example.

It is desirable that the first shoulder lateral grooves 30 are arranged, for example, at an angle of 0 to 20° with respect to the axial direction of the tire. For example, the angle of the first shoulder lateral groove 30 of the present embodiment with respect to the tire axial direction gradually increases inward in the tire axial direction.

The second shoulder sipe 32, for example, extends axially inward from the first tread end Te1. The axially inner end 32 i of the second shoulder sipe 32 is cut off within the first shoulder land portion 8 . In a more desirable aspect, the inner end 32i of the second shoulder sipe 32 is located closer to the first tread end Te1 than the inner end 30i of the first shoulder lateral groove 30 is. Such a second shoulder sipe 32 serves to make the rigidity distribution of the first shoulder land portion 8 uniform and to improve initial responsiveness.

The axial length L4 of the second shoulder sipe 32 is preferably 0.75 to 0.95 times the axial length L3 of the first shoulder lateral groove 30, for example.

It is desirable that the region where the first non-crossing sipe 13 is extended along its length direction toward the first shoulder land portion 8 passes near the inner end 32i of the second shoulder sipe 32 . Specifically, it is desirable that the minimum distance between the region and the inner edge 32i is less than 5 mm. As a more desirable aspect, in the present embodiment, the region where the first non-crossing sipe 13 is extended along the length direction toward the first shoulder land portion 8 overlaps the inner end 32i of the second shoulder sipe 32. there is Such an arrangement of the first non-crossing sipe 13 and the second shoulder sipe 32 can make the deformation of each sipe uniform during running, thereby enhancing wear resistance.

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 tire of size 195/65R15 having the basic pattern shown in FIG. As Comparative Example 1, as shown in FIG. 5, there is a tire in which the transverse sipes b provided in the middle land portion a are arranged so as not to smoothly continue with the shoulder sipes d provided in the shoulder land portion c. Prototyped. The tire of Comparative Example 1 has substantially the same tread pattern as that shown in FIG. 1, except for the above configuration. Each test tire was tested for handling stability and wear resistance. Common specifications and test methods for each test tire are as follows.
Rim: 15 x 6.0
Tire internal pressure: 200kPa
Test vehicle: 1500cc displacement, front-wheel drive Tire mounting position: All wheels

<Steering stability>
Steering stability (including initial responsiveness during cornering) was evaluated by the driver's senses when the test vehicle was driven on a dry road surface. The results are scored with Comparative Example 1 being 100, and the larger the number, the better the steering stability.

<Abrasion resistance>
A wear energy measuring device was used to measure the wear energy of the tread portion. The results are indexed with the wear energy of Comparative Example 1 being 100, and the smaller the figure, the smaller the wear energy and the better the wear resistance.
The results of the tests are shown in Table 1.

As a result of the test, it was confirmed that the tires of Examples exhibit excellent steering stability without impairing wear resistance.

2 tread portion 3 crown main groove 4 first shoulder main groove 6 first middle land portion 7 second middle land portion 8 first shoulder land portion 11 first transverse sipe 12 second transverse sipe 31 first shoulder sipe Te1 first tread end

Claims (11)

A tire having a tread portion,
The tread portion includes a crown main groove extending continuously in the tire circumferential direction;
a first shoulder main groove extending continuously in the tire circumferential direction between the crown main groove and the first tread end;
a first middle land portion divided between the crown main groove and the first shoulder main groove;
a second middle land portion adjacent to the first middle land portion via the crown main groove;
a first shoulder land portion adjacent to the first middle land portion via the first shoulder main groove;
The first middle land portion is provided with a plurality of first transverse sipes that completely cross the first middle land portion,
the second middle land portion is provided with a plurality of second transverse sipes that completely cross the second middle land portion;
The first shoulder land portion is provided with a plurality of first shoulder sipes extending axially outward from the first shoulder main groove,
Each of the first transverse sipes is arranged so as to be smoothly continuous with each of the first shoulder sipes via the first shoulder main groove, and is arranged to smoothly connect with each of the first shoulder sipes via the crown main groove. Disposed smoothly and out of continuation with each of the transverse sipes,
tire. 2. A region of the first transverse sipe that extends along the length direction toward the first shoulder land portion overlaps an end portion of the first shoulder sipe on the first shoulder main groove side. Tires as stated. A first region in which the first transverse sipe extends along the length direction toward the second middle land portion, and a second transverse sipe extends along the length direction toward the first middle land portion. 3. The tire according to claim 1, wherein the second regions do not overlap each other within the crown main groove. 4. The tire according to claim 3, wherein in the crown main groove, the minimum circumferential distance between the first region and the second region is 3.0 to 6.0 mm. 5. The tire according to any one of claims 1 to 4, wherein at least one of said first transverse sipes has a shallow portion with a raised bottom at positions other than both ends in the tire axial direction. the first middle land portion is provided with a plurality of first non-transverse sipes extending from the crown main groove and interrupted within the first middle land portion;
6. The tire according to any one of claims 1 to 5, wherein the second middle land portion is provided with a plurality of second non-transverse sipes extending from the crown main groove and interrupted within the second middle land portion. 7. The tire of claim 6, wherein each of said first non-transverse sipes is not smoothly continuous with each of said second non-transverse sipes through said crown main groove. a third region in which the first non-crossing sipe extends along its length toward the second middle land portion; 8. The tire of claim 7, wherein the fourth regions extending inwards do not overlap each other within the crown main groove. The tire according to claim 8, wherein in the crown main groove, the minimum circumferential distance between the third region and the fourth region is 1.0 to 2.0 mm. A chamfered portion is provided at a communicating portion between the crown main groove and the first non-transverse sipe,
10. The chamfered portion according to any one of claims 6 to 9, wherein said chamfered portion has an inclined surface that is continuous with each of the tread surface of the first middle land portion, the groove wall of the crown main groove, and the sipe wall of the first non-transverse sipe. tire. The first shoulder land portion is provided with a second shoulder sipe extending in the axial direction of the tire,
the axially inner end of the second shoulder sipe is interrupted within the first shoulder land portion;
11. The region according to any one of claims 6 to 10, wherein a region extending the first non-crossing sipe along its length direction toward the first shoulder land portion overlaps with the inner end of the second shoulder sipe. tires.

Images