JP2000280713A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure performance on snow even in a pattern having a circumferential directional straight groove by arranging a plurality of projections extending toward a land part base part from a tire surface and increasing in a tire axis directional dimension in the tire circumferential direction at least on one tire axis directional side surface of a circumferential directional land part row. SOLUTION: In a tread 12 of a tire, circumferential directional wide grooves are formed on the tire axis directional both sides by sandwiching a tire equatorial surface. While, projections 35 extending toward a base part of a rib-shaped land part l20 from a tire surface and increasing in a tire axis directional dimension toward the base part of the rib-shaped land part 20 are arranged in a plurality in the tire circumferential direction on a side surface (a groove wall surface of a circumferential wide groove) of the rib-shaped land part 20. Since the projections 35 bite and hitch on a snow surface when traveling on snow, high traction performance and brake performance can be obtained. When the tire rolls and treads on snow during traveling, the edge of the projections 35 effectively operates to improve performance on snow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having excellent performance on ice and snow.

[0002]

2. Description of the Related Art A winter pneumatic tire, a so-called studless tire, typically has a tread pattern as shown in FIG. 3, and has a circumferential groove 100 extending in a zigzag shape continuous with a tread 108 in a circumferential direction. In general, a pattern in which a plurality of land portions 106 are formed by a circumferential groove 102 extending in the shape of a circle and a lateral groove 104 extending in the tire axial direction.

[0003]

With the conventional single groove angle,
In the case of a pattern having circumferential straight grooves, the circumferential straight grooves have no block edge component in the front-rear direction of rotation, and thus have no effect on traction, braking, and the like. Also, when the groove volume is reduced due to wear, the performance on snow tends to deteriorate.

[0004] In view of the above fact, it is an object of the present invention to provide a pneumatic tire capable of obtaining performance on snow even in a pattern having a straight groove in the circumferential direction.

[0005]

According to a first aspect of the present invention, there is provided a tread including a circumferential land portion row extending in the tire circumferential direction facing a main groove extending at least one in the tire axial direction along the tire circumferential direction. A pneumatic tire provided on a surface portion, wherein at least one tire axial side surface of the circumferential land portion row extends from a tire surface toward a land base portion, and a tire axial dimension toward the land portion base portion. Are provided in the tire circumferential direction.

Next, the operation of the pneumatic tire according to the first aspect will be described.

[0007] In the pneumatic tire according to the first aspect, since a plurality of projections are provided on the side surface in the tire axial direction of the circumferential land portion row, the projections in the ground contact surface when the vehicle runs on snow have a snow surface. As a result, high traction performance and braking performance on snow can be obtained.

Further, in a normal tire, when the tread wears, the traction performance and the braking performance decrease due to a decrease in the groove area and the like. However, in the pneumatic tire of the present invention, the protrusion on the tire surface in the tire axial direction is caused by the tread wear. Since the edge is extended, a decrease in traction performance and braking performance due to tread wear is suppressed.

According to a second aspect of the present invention, in the pneumatic tire according to the first aspect, the shape of the projection as viewed in the tire axial direction is rectangular.

Next, the operation of the pneumatic tire according to claim 2 will be described.

[0011] In the pneumatic tire according to the second aspect, the rigidity of the land portion can be ensured by making the shape of the projections rectangular when viewed from the tire axial direction.

According to a third aspect of the present invention, in the pneumatic tire according to the first or second aspect, an angle of a side surface in a tire axial direction of the projection with respect to a normal line on the tread is zero.
It is characterized in that the angle difference is within a range of about 50 °, and the angle difference between the side surface of the protrusion in the tire axial direction and the side surface of the land adjacent to the circumferential surface of the protrusion in the tire axial direction is 3 ° or more.

Next, the operation of the pneumatic tire according to claim 3 will be described.

The angle of the side surface in the tire axial direction of the projection with respect to the normal depends on the setting of the groove width of the circumferential groove located on the side in the tire width direction of the circumferential land portion row. Is most effective within a range of 0 to 50 °.

Here, if the angle of the side surface of the projection in the tire axial direction with respect to the normal exceeds 50 °, the groove volume required for running on snow or wet running becomes considerably small, and these performances may be deteriorated.

The angle difference between the side surface of the protrusion in the tire axial direction and the side surface adjacent to the circumferential surface of the tire axial direction is 3 °.
Otherwise, the protrusion cannot form an effective edge when the tread is worn, and sufficient traction performance and braking performance cannot be obtained when the tread is worn.

According to a fourth aspect of the present invention, in the pneumatic tire according to any one of the first to third aspects,
The circumferential length of the protrusion on the tire surface side is:
The width of the main groove is in the range of 10 to 250% of the groove width, and the interval between the protrusions in the tire circumferential direction is 50 to 300% of the length of the protrusion in the tire circumferential direction.

Next, the operation of the pneumatic tire according to claim 4 will be described.

The circumferential length of the protrusion on the tire surface side in the tire circumferential direction is set within a range of 10 to 250% of the groove width, and the interval between the protrusions in the circumferential direction of the tire is 50 to 30 of the circumferential length of the protrusion.
When it is set to 0%, the projection can exhibit the performance most effectively in running on snow.

When the length of the protrusion on the tire surface side in the tire circumferential direction is less than 10% of the groove width, it is difficult for snow to enter between the protrusions, and the effect on snow decreases.

If the length of the protrusion on the tire surface side in the tire circumferential direction exceeds 250% of the groove width, the number of protrusions in the ground contact surface decreases, and the effect of the protrusion decreases.

If the interval between the protrusions in the tire circumferential direction is less than 50% of the length of the protrusions in the tire circumferential direction, the width of the concave portion between the protrusions becomes narrow, and snow cannot enter the concave portion properly. Less effective.

If the distance between the protrusions in the tire circumferential direction exceeds 300% of the length of the protrusion in the tire circumferential direction, the number of protrusions in the ground contact surface decreases, and the effect of the protrusions decreases. Also,
The length of the protrusion becomes relatively short, and the rigidity of the land decreases, which affects steering stability.

According to a fifth aspect of the present invention, in the pneumatic tire according to any one of the first to fourth aspects,
The circumferential land portion row is substantially continuous in the tire circumferential direction, the circumferential land portion row has a sub-groove extending from one side surface in the tire axial direction and terminating in the land portion, Sub-grooves extending from the other side surface and terminating in the land portion are alternately arranged in the tire circumferential direction.

Next, the operation of the pneumatic tire according to claim 5 will be described.

In order to improve the performance on ice, it is necessary to secure a ground contact area. In order to secure the ground contact area, it is important to secure the area that actually contacts the road surface by suppressing the fall of the land portion at the time of ground contact, in addition to reducing the groove area in consideration of wet performance and the like.

[0027] In the pneumatic tire according to the fifth aspect, the circumferential land portion row is substantially continuous in the tire circumferential direction, and the circumferential land portion row has a sub-groove terminating in the land portion having a tire shaft. Since the tires extend alternately in the tire circumferential direction from both sides in the tire direction, the reduction of the ground contact area due to the grooves is also suppressed, and the rigidity of the tire in the circumferential direction of the circumferential land row is secured and the fall in contact with the ground is suppressed. Thus, the contact area required for the performance on ice is secured.

Further, the traction performance and the braking performance on snow are improved by the sub-groove provided in the circumferential land portion.

According to a sixth aspect of the present invention, in the pneumatic tire according to the fifth aspect, the sub-groove extending from one side in the tire axial direction and the sub-groove extending from the other side in the tire axial direction are: It does not overlap when projected in the tire circumferential direction.

Next, the operation of the pneumatic tire according to claim 6 will be described.

When the sub-groove extending from one side surface in the tire axial direction and the sub-groove extending from the other side surface in the tire axial direction overlap when projected in the tire circumferential direction, the rigidity of the circumferential land portion row in the tire circumferential direction is increased. , And fall down at the time of contact with the ground, leading to a reduction in the contact area.

Therefore, by making the sub-groove extending from one side surface in the tire axial direction and the sub-groove extending from the other side surface in the tire axial direction not overlap in the tire circumferential direction, the tires in the circumferential land row The rigidity in the circumferential direction is secured, and the ground contact area required for performance on ice is secured.

According to a seventh aspect of the present invention, in the pneumatic tire according to any one of the first to sixth aspects,
The circumferential land portion row is characterized in that sipes extending in the transverse direction of the circumferential land portion row are arranged at substantially equal intervals in the tire circumferential direction. Next, the operation of the pneumatic tire according to claim 7 will be described.

In the pneumatic tire according to the seventh aspect, since the sipe is provided so as to cross the land portion row in the circumferential direction, the on-ice performance is improved by the edge effect of the sipe.

According to an eighth aspect of the present invention, in the pneumatic tire according to the seventh aspect, the protrusion is defined by the adjacent sipe and the sipe or the adjacent sipe and the sub-groove. The protrusions are disposed every other portion, and the length of the protrusion in the tire circumferential direction is substantially equal to the length of the small land portion in the tire circumferential direction.

Next, the operation of the pneumatic tire according to claim 8 will be described.

When the pneumatic tire rolls and touches the ground,
Since the groove width of the sipe and the groove width of the sub-groove are reduced, the distance between the protrusions is also reduced accordingly. For this reason, when traveling on snow, when the distance between the protrusions is reduced, the protrusions can grasp the snow on the road surface with each other, and the edges of the protrusions can be effectively operated,
The performance on snow improves.

According to a ninth aspect of the present invention, in the pneumatic tire according to any one of the first to eighth aspects,
The protrusion is formed on an outer surface in the tire axial direction of the circumferential land portion row.

Next, the operation of the pneumatic tire according to the ninth aspect will be described.

In this case, since the projection is formed relatively outside the tread, cornering on snow can be improved.

According to a tenth aspect of the present invention, in the pneumatic tire according to any one of the first to eighth aspects, the protrusion is formed on the inner surface in the tire axial direction of the circumferential land portion row. It is characterized by being.

Next, the operation of the pneumatic tire according to the tenth aspect will be described.

In this case, since the projection is formed relatively at the center of the tread, traction on snow is improved.

According to an eleventh aspect of the present invention, in the pneumatic tire according to any one of the first to tenth aspects, a side surface of the projection on the tire circumferential direction side is substantially parallel to the tire axial direction. It is characterized by being parallel.

Next, the operation of the pneumatic tire according to the eleventh aspect will be described.

The edge for improving traction performance and braking performance is preferably parallel to the tire axial direction. For this reason, the side surface on the tire circumferential direction side of the projection is
Preferably, it is substantially parallel to the tire axial direction.

The fact that the side surface of the protrusion on the tire circumferential side is substantially parallel to the tire axial direction makes it easier to grasp the snow on the road surface between the protrusions when the tire is in contact with the snow surface. Easy to release snow when away from

[0048]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the pneumatic tire of the present invention will be described with reference to FIGS.

In the figure, the directions of arrows L and R indicate the tire axial direction, the direction of arrow A indicates the tire rotation direction, and the direction of arrow B indicates the traveling direction of the tire.

As shown in FIG. 2, the tread 12 (tread width W) of the pneumatic tire 10 (tire size: 205 / 65R15) of the present embodiment has tires on both sides in the tire axial direction with the tire equatorial plane CL interposed therebetween. A circumferential wide groove 14 extending along the circumferential direction is formed.
A circumferentially narrow groove 16 extending in the tire circumferential direction is formed on the outer side in the tire axial direction.

A plurality of transverse grooves 18 are formed in the tread 12 from the tread end 12L in the direction of the arrow L in FIG. 2 and the tread end 12R in the direction of the arrow R in FIG. 2 toward the tire equatorial plane CL. Have been.

The transverse groove 18 extending from the tread end 12L in the direction of the arrow L and the transverse groove 18 extending from the tread end 12R in the direction of the arrow R are each formed in a straight line, and are each inclined upward to the right.

As shown in FIG. 3, the angle θ1 formed by the transverse groove 18 with respect to the tire circumferential direction is preferably in the range of 40 ° to 90 °, and in the present embodiment, the angle θ1 is set to 70 °.

As shown in FIG. 2 and FIG.
Crosses the circumferential narrow groove 16 and the circumferential wide groove 14,
A rib-shaped land portion 20 having an axially inner end portion 18A formed between the circumferentially wide grooves 14 and extending continuously along the tire circumferential direction.
Is located within.

In the rib-shaped land portion 20, the tread end 12L
Axial end 18A of the transverse groove 18 extending from the tread end 12R.
Are arranged alternately in the tire circumferential direction, and do not overlap each other when projected in the tire circumferential direction.

The transverse groove 18 is preferably formed such that the groove width is smaller on the axial inner end 18A side than on the tread ends 12L, R side as in this embodiment.
A straight wall portion 18B and a zigzag portion 18C
Are preferably provided alternately.

As shown in FIG. 3, in a substantially rhombic region surrounded by the circumferential wide groove 14, the circumferential narrow groove 16 and the two transverse grooves 18, the transverse grooves 18 are located with respect to the tire circumferential direction. A sub-groove 22 having a constant width extending substantially linearly and inclined in the opposite direction is formed to bisect the substantially rhombic region,
A substantially triangular first land portion 24 is defined by the sub-groove 22, the circumferential wide groove 14 and the transverse groove 18 inside the sub-groove 22 in the tire axial direction, and a sub-groove outside the sub-groove 22 in the tire axial direction. A substantially trapezoidal second land portion 26 is defined by the circumferential narrow groove 16 and the transverse groove 18.

Further, in the sub-groove 22 of the present embodiment, the tire equatorial plane CL side is connected to the circumferential wide groove 14.

The inclination angle θ that the sub-groove 22 makes with the tire circumferential direction
2 is preferably in the range of 30 ° to 70 °, and particularly preferably about 45 °. The inclination angle θ2 of the sub-groove 22 in this embodiment is set to 45 °.

The width of the sub-groove 22 is preferably equal to or greater than the width of the transverse groove 18 in the tread central section 28.

Here, the tread central area 28 in this embodiment is an area between the circumferential narrow grooves 16.

The groove width W1 of the circumferentially wide groove 14 gradually increases from one end side of the first land portion 24 in the tire circumferential direction to the other end side.

The groove width W1 of the wide groove 14 in the circumferential direction is preferably about 4 to 15 mm as an actual dimension in the case of a tire for a passenger car. In the present embodiment, the groove width W1 of the circumferentially wide groove 14 is
The maximum width is 8.5 mm, the minimum width is 6.5 mm, and the average is 7.5 mm.

A substantially rhombus-shaped third land portion 30 is defined outside the circumferential narrow groove 16 in the axial direction by the circumferential narrow groove 16 and the transverse groove 18. (Sipe) The rib-shaped land portion 20 is provided with a plurality of sipes 32 that extend across the rib-shaped land portion 20 at substantially equal intervals in the tire circumferential direction.

The sipe 32 of this embodiment has a zigzag shape and is provided in parallel with the transverse groove 18.

A zigzag short sipe 33 connecting the transverse grooves 18 is formed at the center of the rib-like land portion 20 in the tire axial direction. A pseudo sipe 34 (a part of the sipe 32 + the short sipe 33) is formed to bend and extend along the tire equatorial plane CL.

On the other hand, the side surface of the rib-shaped land portion 20 (the groove wall surface of the circumferentially wide groove 14) is located on the side of the tire from the rib surface.
A plurality of protrusions 35 extending toward the base of the tire and extending in the tire axial direction toward the base of the rib-shaped land portion 20 are provided in the tire circumferential direction.

The protrusions 35 are provided on every other land portion divided by the sipe 32 and the sipe 32 (or the transverse groove 18), and the tire circumferential length is the tire circumferential direction length of the land portion. Is consistent with

The protrusion 35 of the present embodiment has a side surface 35B on the tire circumferential direction side parallel to the sipe 32 (and the transverse groove 18), and an angle between the side surface 35B and the tire axial direction is 20 °.
It is.

The projection 35 of the present embodiment has a vertically long substantially right-angled triangular shape when viewed from the tire circumferential direction, and has a vertically long rectangular shape (the rib-shaped land portion 20) when viewed from the tire axial direction. The width is constant from the base to the tread surface 20A.).

When the pneumatic tire 10 is new, the tread surface 20A of the rib-like land portion 20 has a constant width (17.5 mm in this embodiment), and the tread surface 20A of the rib-like land portion 20
Are linearly extended in the tire circumferential direction.

The height of the projection 35 is the same as the height of the rib-shaped land portion 20, and the top on the tire radial outer side coincides with the edge of the tread surface 20 A of the rib-shaped land portion 20.

As shown in FIG. 1, in the present embodiment, the side surface (the portion other than the projection 35) 20B of the rib-shaped land portion 20 facing the tire axis direction is formed by a normal S on the tread surface 20A.
The angle θ3 of the side surface 35A of the projection 35 with respect to the normal line S and facing the tire axial direction is set to 12 °.

The circumferential length L1 of the protrusion 35 on the tread surface 20A side is preferably within the range of 10 to 250% of the groove width facing the protrusion 35, that is, the groove width W1 of the circumferential wide groove 14. Actual dimensions for passenger car tires are 2-1
It is preferably about 0 mm.

On the other hand, the tread surface 2 between the projections 35
The interval dimension L2 on the 0A side is the circumferential length L of the protrusion 35.
1 is preferably in the range of 50 to 300%.

In this embodiment, the circumferential length L of the projection 35
1 is set to 6 mm, and the distance L2 between the protrusions 35 is set to 6 mm.

As shown in FIG. 3, the first land portion 24 includes
A plurality of sipes 36A to 36D having one end connected to the circumferential wide groove 14 are provided in parallel with the transverse groove 18, and a sipe 38 connecting one end to the transverse groove 18 is provided to be inclined in a direction opposite to the sipe 36. A sipe 40 connected to the sub-groove 22 is provided to be inclined in a direction opposite to the sipe 36.

At the center of the first land portion 24, the end of the sipe 36A in the land is connected to the middle of the sipe 38, and the end of the sipe 36B in the land is connected to the middle of the sipe 40. The end of the sipe 38 in the land is a sipe 36B
Is connected to the middle part of the sipe 40, and the end in the land part of the sipe 40 is connected to the middle part of the sipe 36C, thereby forming a pseudo sipe 42 that bends and extends along the tire equatorial plane CL.

Next, the second land portion 26 is provided with a plurality of sipes 44A to 44D each having one end connected to the circumferential narrow groove 16 in parallel with the transverse groove 18, and having one end connected to the sub-groove 22. 46 is provided to be inclined in a direction opposite to the sipe 44,
The sipe 48 whose one end is connected to the transverse groove 18 is the sipe 4
4 is provided in the opposite direction.

At the center of the second land 26, the end of the sipe 46 in the land is connected to the middle of the sipe 44B, and the end of the sipe 48 in the land is connected to the middle of the sipe 44C. , The end of the land of the sipe 44C is the sipe 46.
Is connected to the middle part of the sipe 44D, and the end in the land of the sipe 44D is connected to the middle part of the sipe 48, thereby forming a pseudo sipe 50 that bends and extends along the tire equatorial plane CL.

Further, in the third land portion 30, sipes 52A to 52D, one ends of which are connected to the end on the shoulder side, are provided with the transverse grooves 1.
8 and a sipe 54 having one end connected to the circumferential narrow groove 16 is provided inclining in a direction opposite to the sipe 52, and a sipe 56 having one end connected to the transverse groove 18 is provided with the sipe 52. It is provided inclined in the opposite direction.

At the center of the third land portion 30, the end of the sipe 52A in the land is connected to the middle of the sipe 54A, and the end of the sipe 52B in the land is connected to the middle of the sipe 54B. The end of the sipe 52C in the land is connected to the middle of the sipe 54C, the end of the sipe 52D in the land is connected to the middle of the sipe 56, and the end of the sipe 54B in the land is connected to the middle of the sipe 52A. The end of the sipe 54C in the land is connected to the middle of the sipe 52B, and the end of the sipe 56 in the land is connected to the middle of the sipe 52C. A pseudo sipe 58 is formed to bend and extend.

The negative rate of the tread 12 of this embodiment is 35.7%. (Operation) Next, the operation of the pneumatic tire 10 of the present embodiment will be described. (1) In the pneumatic tire 10 of the present embodiment, since the plurality of protrusions 35 are provided on the side surface of the rib-shaped land portion 20 in the tire axial direction, the protrusions 35 in the ground contact surface 60 when running on snow. Since it is entangled and caught on the snow surface, high traction performance and braking performance on snow can be obtained.

Also, when the tire rolls on running on snow and comes into contact with the ground, the distance between the projections 35 is reduced and the snow is gripped between the side surfaces 35B and 35B which are parallel to each other. The edge of the can work effectively, so the performance on snow is improved.

Further, the snow between the projections 35 is eliminated because the distance between the projections 35 increases when the snow leaves the road surface. Therefore, it becomes possible to catch the snow again between the projections 35 after one rotation.

It is preferable that the side surfaces 35B and 35B facing each other be parallel in order to grasp the snow with the protrusions 35 when touching the ground and remove the snow when leaving the road surface.

For example, when the two side surfaces 35B are inclined so as to move away from each other toward the groove side (when viewed from the tread side, the protrusion 35 has a narrow trapezoidal shape), it is difficult to grip the snow between the protrusions 35. Become. Therefore, in this way, the side surface 35B
Is inclined, the side surface 3 with respect to the tire axial direction
The angle of 5B is preferably set to 10 ° or less.

When the two side surfaces 35B are inclined so as to approach each other toward the groove side (when the projection 35 is trapezoidal when the groove side is wide when viewed from the tread side), snow clogs between the projections 35. It will be easier. Therefore, when the side surface 35B is inclined as described above, the angle of the side surface 35B with respect to the tire axial direction is preferably set to 10 ° or less. (2) When new, as shown in FIG. 4A, the shape of the tread surface 20A of the rib-shaped land portion 20 (only the portion that actually contacts the road surface is shown) has a constant width. (For example, 50% abrasion. When the portion indicated by the dashed line in FIG. 1 has worn down.), The tread surface 20 of the rib-like land portion 20
The shape of A is as shown in FIG. 4 (B), and the edge of the side surface 35B on the tire circumferential direction of the protrusion 35 extends on the tire surface, so that the traction performance and the braking performance due to the wear of the tread 12 decrease. Is suppressed. (3) Since the shape of the projection 35 as viewed from the tire axial direction is rectangular, the rigidity of the rib-shaped land portion 20 can be ensured. (4) The angle θ3 of the side surface 35A of the protrusion 35 in the tire axial direction with respect to the normal S set on the tread surface 20A is 12
And the angle difference between the side surface 35A of the protrusion 35 and the land side surface 20B adjacent in the circumferential direction of the tire axial side surface is 12 °.
Therefore, the protrusion 35 can form an effective edge when the tread 12 is worn.

If the angle θ3 of the side surface 35A of the projection 35 exceeds 50 °, the groove volume required for running on snow or running wet decreases, and it is considered that these performances are deteriorated. The angle difference between the side surface 35A and the land side surface 20B is 3
If not, the protrusion 35 cannot form an effective edge when the tread 12 is worn, and sufficient traction performance and braking performance cannot be obtained when worn. (5) Since the tire circumferential length L1 on the tire surface side of the protrusion 35 is 6 mm with respect to the groove width W1 of the circumferential wide groove 14 of 7.5 mm (average value), the tire on the tire surface side of the protrusion 35 The circumferential length L1 / the circumferential width W1 of the wide groove 14 is 80%.

Further, the distance L2 in the tire circumferential direction between the projections 35
Is 6 mm, and the tire circumferential length L1 of the protrusions 35 is 6 mm, so the tire circumferential direction distance L2 between the protrusions 35 / the tire circumferential length L1 of the protrusions 35 is 100%.

Thus, the projection 35 can exhibit the most effective performance when traveling on snow.

Here, if the tire circumferential length L1 of the protrusion 35 on the tire surface side is less than 10% of the groove width W1 of the circumferential wide groove 14, snow hardly enters between the protrusions 35, and The effect on the is reduced.

The circumferential length L1 of the protrusion 35 on the tire surface side in the tire circumferential direction is 250% of the groove width W1 of the circumferential wide groove 14.
Is exceeded, the number of the protrusions 35 in the ground plane 60 decreases, and the effect of the protrusions 35 decreases.

When the tire circumferential distance L2 between the protrusions 35 is less than 50% of the tire circumferential length L1 of the protrusions 35, the width of the recess between the protrusions 35 becomes narrow, and the snow enters the recess well. The effect on snow is reduced because it disappears.

When the circumferential distance L2 between the protrusions 35 exceeds 300% of the length L1 of the protrusions 35 in the tire circumferential direction, the number of the protrusions 35 in the ground contact surface 60 decreases, and the effect of the protrusions 35 decreases. In addition, the length of the protrusion 35 is relatively shortened, the rigidity of the rib-shaped land portion 20 is reduced, and the steering stability is affected. (6) The pneumatic tire 10 of the present embodiment can obtain high wet performance (hydroplaning) because the water in the ground contact surface can be drained by the circumferential wide groove 14, the sub groove 16, the transverse groove 18, and the sub groove 22. Can be (7) Since the tread 12 is provided with the pair of wide circumferential grooves 14 and the pair of narrow circumferential grooves 16 extending along the tire circumferential direction, high straight running stability and cornering performance on snow are obtained. Can be (8) Since a plurality of transverse grooves 18 extending from the tread ends L and R to the rib-shaped land portions 20 are arranged in the tread 12 in the tire circumferential direction, high traction performance and braking performance can be obtained. (9) A high drainage property when wet is obtained by the linear sub-groove 22 that bisects a substantially rhombic region surrounded by the circumferential wide groove 14, the circumferential narrow groove 16 and the two transverse grooves 18. Furthermore, when the tire steps on the contact surface 60, the groove edge of the sub-groove 22 inclined with respect to the tire circumferential direction continuously enters the contact surface 60, so that high traction performance at the time of cornering can be obtained.

Further, the cornering performance on ice and snow can be obtained by the sub-grooves 22 extending inclining with respect to the tire circumferential direction. (10) On the tire equatorial plane CL, the rib-shaped land portions 20 that are continuous in the tire circumferential direction are provided.
Rigidity near the tire equatorial plane CL of No. 2 can be secured. Therefore, the entire tread surface 20A of the rib-shaped land portion 20 can be reliably brought into contact with the road surface, and high braking performance and traction performance mainly on ice can be obtained.

[0097] The rib-shaped land portion 20 has a tread end 1.
A part of the transverse groove 18 extending from the 2L (axial inner end 18
A) and a part of the transverse groove 18 extending from the tread end 12R (the inner end 18A in the axial direction) are alternately arranged in the tire circumferential direction, so that braking performance and traction performance on snow can be obtained. Can be

When a block-shaped land portion defined by a lateral groove is formed near the tire equatorial plane CL, the block-shaped land portion has a lower rigidity in the tire circumferential direction than the rib-shaped land portion. The fall of the block-shaped land portion occurs, and as a result, a portion of the land portion that does not touch the road surface occurs, and the braking performance and traction performance on ice are reduced.

On the other hand, in this embodiment, the tire equatorial plane CL
The rib-shaped land portion 20 formed along the
A part of the transverse groove 18 extending from the 2L (axial inner end 18
A) and a portion of the transverse groove 18 extending from the tread end 12R (the inner end 18A in the axial direction) are alternately arranged in the tire circumferential direction, and these are not overlapped when projected in the tire circumferential direction. Therefore, the rigidity of the rib-shaped land portion 20 is ensured, and there is no decrease in braking performance and traction performance on ice due to the provision of the transverse groove 18. (11) A portion 18B having a straight side wall surface in the transverse groove 18
The reason why the zigzag portions 18C and the zigzag portions 18C are alternately provided is that if only the zigzag portions 18C are provided, the hydroplaning performance at the time of cornering is deteriorated. Are alternately provided to balance the horizontal edge component, thereby ensuring both hydroplaning performance during cornering and improved skid resistance on snow. (12) Adjust the groove width of the transverse groove 18 to the tread end side 12L,
Since the diameter of the inner end portion 18A is narrower than the radius R, the negative rate of the tread central section 28 having a relatively high contact pressure can be suppressed, and a high on-ice braking performance can be obtained. (13) The inclination angle θ2 of the auxiliary groove 22 with the tire circumferential direction
Is set within the range of 30 to 70 ° because the auxiliary groove 22 (1
This is because the angle of contact is the angle that makes it easier to rush into the contact surface 60 most continuously.

When the inclination angle θ2 of the sub-groove 22 is set to 45 °, it works effectively also at the time of traction and works effectively at the time of cornering, so that the front-back and lateral performance can be compatible. (14) By making the width of the sub-groove 22 equal to or greater than the width of the transverse groove 18 in the tread central section 28, drainage of the sub-groove 22 is improved, and high wet performance is obtained.
In addition, the bite against snow is particularly improved, and high traction performance on snow is obtained. (15) In the pneumatic tire 10 of the present embodiment, the sipe 32 and the first land 2
4. Sipe 36A to 36C, 38, 40, 2nd land part 2
6 Sipe 44A-44D, 46, 48, 3rd land part 3
Since the sipe 52A-D, 54A-C, and 56 are formed in 0, high performance on snow and ice as a studless tire can be obtained. (16) The rib-shaped land portion 20 is formed with a pseudo-sipe 34 which is bent and extends along the tire equatorial surface CL on the tire axial center portion, that is, on the tire equatorial surface CL. In No. 20, the edge density of the sipe is such that the central portion in the tire axial direction is on both sides (the circumferential wide groove 1).
4 part).

During traveling on ice, when a land portion of the tread contacts the road surface (ice surface) and pressure acts on the ice, a water film is generated between the land portion and the road surface (ice surface). Although the water generated between the land and the road surface (ice surface) is more difficult to escape in the central part than in the peripheral part of the land, in the present embodiment, the pseudo sipe 3
4, the edge density of the center portion in the tire axial direction of the rib-like land portion 20 is increased, so that the water film is cut by the sipe edge and the amount of water absorbed by the sipe is increased, thereby providing high on-ice braking performance and on-ice traction performance. Is obtained.

The pseudo sipe 34 of the rib-shaped land portion 20 is also provided.
Extends along the tire circumferential direction, so that high lateral performance on ice and snow, for example, high cornering performance can be obtained. (17) In the first land portion 24, the tire equatorial plane CL
A pseudo sipe 42 that bends and extends along is formed. In the second land portion 26, a pseudo sipe 50 that bends and extends along the tire equatorial plane CL is formed. A pseudo sipe 58 bent and extended along the tire equatorial plane CL is formed, and the edge density of the sipe in each land portion is lower at the peripheral portion than at the central portion, so that each land portion has sufficient peripheral portion rigidity. In addition, the rigidity of the central portion can be reduced, the fall of the land portion can be suppressed, the contact area can be secured, and the performance on ice and snow due to the fall of the land portion can be prevented. (18) Sipe 32L, 32R, 36A-36C, 3
8, 40, 44A to 44D, 46, 48, 52A to D,
Since each of 54A-C and 56 has a zigzag shape, the edge component can be increased in both the tire circumferential direction and the tire axial direction, and thereby, particularly, cornering performance on ice can be improved. (19) In each land portion, the sipe in the arrow L direction and the sipe in the arrow R direction are inclined in opposite directions with respect to the center line in the tire axial direction of the land portion, so that the sipe in the land portion has directionality. As a result, it is possible to reduce the anisotropy of rigidity in the land portion, and it is possible to suppress unevenness in deformation such that it is difficult to deform in one direction and easy to deform in the other direction. Therefore, the problem that the characteristics change depending on the steering angle of the steering wheel, that is, the direction of the pneumatic tire 10 does not occur.

In the case where the sipe is inclined in the same direction, there is a problem that the sipe edge effect is generated in a certain direction but not in the other direction. (20) Sipe 36, 38, 40, 44, 46, 4
8, 52, 54, and 56 have zigzag shapes, and the trajectory of the center of amplitude is linear, so that it is easy to manufacture a mold blade (a plate material forming a sipe) for molding the pneumatic tire 10. Become.

In this embodiment, the projection 35 is formed on the side surface of the rib-shaped land portion 20 in the tire axial direction. However, other land portions (the first land portion 24 and the second land portion in this embodiment). The protrusions 35 may be formed on the side surfaces of the second land portion 26 and the third land portion 30).

In this embodiment, the tire equatorial plane CL
Is provided with one rib-shaped land portion 20, but the present invention is not limited to this, and a plurality of rib-shaped land portions extending continuously along the tire circumferential direction may be provided. Of course, a projection may also be formed on the side surface of the portion. When the protrusion is provided on the rib-shaped land portion, the protrusion may be provided on both side surfaces, may be provided only on the inner side surface in the tire axial direction, or may be provided only on the outer side surface in the tire axial direction.

When the protrusion is provided on the side surface of the rib-shaped land portion on the outer side in the tire axial direction, the protrusion is formed relatively outside the tread, so that cornering on snow can be improved.

When the protrusion is provided on the inner side surface of the rib-shaped land portion in the tire axial direction, the protrusion is formed relatively at the center of the tread, so that traction on snow is improved.

In the present embodiment, the land side surface (the portion other than the projection 35) 2 of the rib-shaped land portion 20 facing the tire axial direction.
0B is parallel to the normal S, and the side surface 35A of the protrusion 35 has a side surface 35A such that the axial dimension gradually increases toward the base of the rib-shaped land portion 20 (the groove bottom of the circumferential wide groove 14). Although the angle θ3 of the side surface 35A with respect to the normal S is set to 12 °, the present invention is not limited to this, and at least unevenness is formed on the side surface of the rib-shaped land portion 20 in the tire axial direction. It is sufficient that the dimensional difference in the tire axial direction gradually increases toward the base of the rib-shaped land portion 20.
B may be a reverse taper (that is, the width of the rib-shaped land portion 20 becomes smaller toward the base portion).

As described above, the land side surface 2 of the rib-shaped land portion 20
If 0B is a reverse taper, the side surface 35 of the projection 35
A may be parallel to the normal line S (however, the angle difference between the land side surface 20B and the side surface 35A is preferably 3 ° or more), and the side surface 35A also has an inverse taper like the land portion side surface 20B. There may be. However, if the angle of the reverse taper is too large, the rigidity of the rib-shaped land portion 20 decreases, which is not preferable.

In the present embodiment, the inclination direction of the transverse groove 18 is the same direction on both sides of the tire equatorial plane CL, and the inclination direction of the sub-groove 22 is the same direction on both sides of the tire equatorial plane CL. The inclining direction of the transverse groove 18 and the inclining direction of the auxiliary groove 22 may be opposite directions on both sides of the tire equatorial plane CL, and the tread pattern may be a directional pattern.

In the pneumatic tire 10 of the present embodiment, a rib (rib-shaped land portion 20) is disposed at the center of the tread 12, and block-shaped land portions (first land portion 24, second land portion 24) are provided on both sides thereof. Although the land portion 26 and the third land portion 30) are arranged, the positions of the ribs and the block-shaped land portions are not limited to the embodiment. Further, the present invention can be applied to a tire having a rib pattern. (Test Example) In order to confirm the effect of the present invention, a tire according to an embodiment to which the present invention is applied and a tire according to a conventional example are prepared.
We compared snow feeling, snow braking performance, snow traction performance, ice feeling and ice braking performance.

Example tire: A tire having the pattern and dimensions described in the embodiment (tire size: 205 /
65R15) (see FIGS. 1 to 3).

Tire of Comparative Example: The tire has the same pattern as the tire of the example, and is the same as the tire of the example except that no projection is formed.

Conventional tire: As shown in FIG. 5, a plurality of circumferential grooves 100 extending zigzag in the circumferential direction of a plurality of tires.
A block-shaped land portion 10 defined by a circumferential groove 102 extending linearly and a lateral groove 104 extending in the tire axial direction.
6 are provided on the tread 108 (tire size: 195 / 65R15).
Plural sipes 11 extending linearly along the tire axial direction
0 are formed at substantially equal intervals in the tire circumferential direction.

The width of the circumferential groove 100 is 7 mm, and the width of the circumferential groove 1 is 1 mm.
02 has a groove width of 7.5 mm, lateral groove 104 has a groove width of 7.5 mm,
The width of the sipe 110 is 0.5 mm. The negative rate of the tread is 45%. Feeling on snow: Comprehensive feeling evaluation of braking performance, starting performance, straight running performance and cornering performance on a test course on a snow-covered road. The evaluation is represented by an index with the conventional example being 100, and the larger the index is, the better the feeling on snow is. Brake performance on snow: The braking distance when fully braking on compressed snow from 40 km / h was measured. The evaluation was expressed by an index with the reciprocal of the braking distance of the conventional example being 100. The higher the index, the better the braking performance on snow. Traction performance on snow: Acceleration time from starting at a distance of 50 m on compacted snow was measured. The evaluation was represented by an index with the reciprocal of the acceleration time of the conventional example being 100. The higher the index, the better the traction performance on snow. Feeling on ice: Comprehensive feeling evaluation of braking performance, starting performance, straight running performance and cornering performance on a test course on an ice surface. The evaluation is represented by an index with the conventional example being 100, and the larger the index is, the better the feeling on ice is. Brake performance on ice: The braking distance was measured when the vehicle was fully braked on an ice plate from 20 km / h. The evaluation was expressed by an index with the reciprocal of the braking distance of the conventional example being 100. The higher the index, the better the braking performance on snow.

[0116]

[Table 1]

As a result of the test, the tire of the embodiment to which the present invention was applied showed a feeling on snow, a braking performance on snow, a traction performance on snow, a feeling on ice, and a feeling on ice, as compared with the tire of the conventional example and the tire of the comparative example. Performance improved in all of the braking performances.

[0118]

As described above, since the pneumatic tire of the present invention has the above-described structure, it has an excellent effect that performance on snow can be obtained even in a pattern having a straight groove in the circumferential direction.

[Brief description of the drawings]

FIG. 1 is a perspective view of a tread of a pneumatic tire according to one embodiment of the present invention.

FIG. 2 is a plan view of a tread of the pneumatic tire according to one embodiment of the present invention.

FIG. 3 is a partially enlarged view of the tread shown in FIG. 2;

FIG. 4 (A) shows a ground contact shape of a tread of a rib-shaped land portion when new, and FIG. 4 (B) shows a ground contact shape of a tread of a rib-shaped land portion when worn.

FIG. 5 is a plan view of a tread of a conventional pneumatic tire.

[Explanation of symbols]

 Reference Signs List 10 Pneumatic tire 12 Tread (tread surface) 14 Circumferentially wide groove (main groove) 16 Circumferentially narrow groove 18 Crossing groove (sub-groove) 20 Rib-shaped land portion (circumferential land row) 20B Land side surface 22 Secondary groove 32 Sipe 35 Projection 35A Tire axial side S normal

Claims (11)

[Claims] 1. A pneumatic tire having a tread tread portion provided with a circumferential land portion row extending in the tire circumferential direction facing a main groove extending at least one in the tire axial direction along the tire circumferential direction, A plurality of protrusions extending in the tire axial direction from the tire surface toward the land base and increasing in the tire axial direction toward the land base are provided on at least one tire axial side surface of the direction land part row. A pneumatic tire characterized by the following. 2. The pneumatic tire according to claim 1, wherein the shape of the projection as viewed from the tire axial direction is rectangular. 3. The angle between the tire axial direction side surface of the projection and the normal to the tread surface is within a range of 0 to 50 °, and the tire axial direction side surface of the projection and the tire axial direction side surface of the projection are included. The angle difference between the land side adjacent to the circumferential direction is 3 °
The pneumatic tire according to claim 1 or 2, wherein there are the above. 4. On the tread side, the length of the protrusion in the tire circumferential direction is within a range of 10 to 250% of the groove width of the main groove, and the interval between the protrusions in the tire circumferential direction is the tire circumferential distance. The pneumatic tire according to any one of claims 1 to 3, wherein the length is 50 to 300% of the length in the direction. 5. The circumferential land portion row is substantially continuous in the tire circumferential direction. The circumferential land portion row has a sub-groove extending from one side surface in the tire axial direction and terminating in the land portion. The sub-grooves extending from the other side surface in the tire axial direction and terminating in the land portion are alternately arranged in the tire circumferential direction. Pneumatic tires. 6. The sub-groove extending from one side surface in the tire axial direction and the sub-groove extending from the other side surface in the tire axial direction do not overlap when projected in the tire circumferential direction. Item 6. A pneumatic tire according to item 5. 7. The tire according to claim 1, wherein sipes extending in the transverse direction of the circumferential land row are arranged at substantially equal intervals in the tire circumferential direction. 7. The pneumatic tire according to any one of the above items 6. 8. The protrusion is disposed every other shore portion defined by the adjacent sipe and sipe, or the adjacent sipe and the sub-groove, and the length of the protrusion in the tire circumferential direction is: The pneumatic tire according to claim 7, wherein the pneumatic tire has a length substantially equal to a length of the small land portion in a tire circumferential direction. 9. The pneumatic tire according to claim 1, wherein the projection is formed on an outer surface of the circumferential land portion row in the tire axial direction. 10. The pneumatic tire according to claim 1, wherein the protrusion is formed on an inner surface of the circumferential land portion row in the tire axial direction. 11. The side surface of the protrusion on the tire circumferential direction side,
The pneumatic tire according to any one of claims 1 to 10, wherein the pneumatic tire is substantially parallel to a tire axial direction.