JP2000225815A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of obtaining high ice and snow performance. SOLUTION: By connecting a sipe extending from one land part end with an intermediate part of a sipe extending from the other land part end and connecting the sipe extending from the other land part end with the intermediate part of the sipe extending from the one land part end in a center area of a first land part 24, a zigzagged pseudo sipe 42 extending along a tire peripheral direction is formed. In the same way, a pseudo sipe 50, a pseudo sipe 58 and a pseudo sipe 34 are formed in a second land part 26, a third land part 30 and a rib-shaped land part 20, respectively. Edge density of sipes is increased in the center areas of the land parts 26, 30, 20. As a result, an edge effective for improving brake performance on ice and traction performance on ice can be constituted and also a water film can be effectively removed. Rigidity of the land parts 26, 30, 20 is secured, falling of the land parts 26, 30, 20 is suppressed, ground contact area can be secured and lowering of ice and snow performance due to falling of the land parts 26, 30, 20 can be prevented.

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 In general, a studless tire has a plurality of circumferential grooves and a plurality of width grooves formed on a tread tread portion, and each block of each block row has a tire circumferential direction. A plurality of sipes having a linear shape, a zigzag shape, a crank shape, or the like extending in the tire width direction at substantially equal intervals are formed.

[0003]

However, in the conventional method of inserting a sipe which divides a block at substantially equal intervals, in order to improve the performance on ice, if the sipe interval in the center portion of the block is narrowed to increase the sipe density, Since the same sipe processing is performed on the peripheral portion of the block, the rigidity of the peripheral portion of the block is reduced.

[0004] Originally, in order to improve the performance on ice, it is necessary to secure the rigidity of the block to some extent, to prevent the block from falling down, and to secure a ground contact area. Although it is better to raise the sipe, the conventional sipe insertion method described above is not advantageous for improving the performance on ice.

The present invention has been made in view of the above-described circumstances, and has as its object to provide a pneumatic tire having high performance on ice and snow.

[0006]

According to the present invention, a plurality of block-shaped land portions defined by a plurality of intersecting grooves are provided on a tread tread portion, and a plurality of sipes are provided on the land portion. A pneumatic tire comprising: a sipe extending from each of at least two land ends of the land to a central area of the land, and a sipe extending from one land end; The sipe extending from the other land end extends in directions opposite to each other, and the sipe extending from one land end is connected to an intermediate portion of the sipe extending from the other land end, and the other sipe extends from the other land end. A sipe extending from the land end is connected to an intermediate portion of the sipe extending from the one land end, so that the central area is formed with a pseudo sipe extending substantially along the tire circumferential direction. I have.

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

In the pneumatic tire according to the first aspect, the performance on ice and snow can be obtained by forming a plurality of sipes on the land.

In the central area of the land, a sipe extending from one land end is connected to an intermediate portion of a sipe extending from the other land end, and a sipe extending from the other land end is connected to the sipe extending from one land end. By connecting to the middle of the extending sipe, a pseudo-sipe having a multi-bent shape, e.g., zigzag, wavy, etc., extending substantially along the circumferential direction of the tire is formed, and the edge density of the sipe is determined by the central area of the land. Is higher than the surrounding area, and water film tends to be generated when traveling on ice.Since the sipe edge component in the central area of the land area can be increased and the sipe density can be increased, it is effective for improving the braking performance on ice and the traction performance on ice Edge can be formed, and the water film can be effectively removed.

Further, since the pseudo sipes extend along the circumferential direction of the tire, lateral performance on ice and snow, for example,
Cornering performance can be improved.

Further, since the edge density of the sipe is lower in the peripheral portion than in the central region of the land portion, the land portion can reduce the rigidity of the central region while securing the rigidity of the peripheral portion. The fall of the part can be suppressed to secure the contact area, and the performance on ice and snow caused by the fall of the land can be prevented.

According to a second aspect of the present invention, in the pneumatic tire according to the first aspect, the sipe is bent a plurality of times.

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

In the pneumatic tire according to the second aspect, since the sipe provided on the land portion is bent a plurality of times, for example, in a zigzag shape or a wavy shape, the edge component increases in both the tire circumferential direction and the width direction. Yes, especially for cornering performance.

According to a third aspect of the present invention, in the pneumatic tire according to the first or second aspect, the sipe extends from at least three land ends of the land to a central area of the land. The sipe extending from each land end is inclined in directions opposite to each other.

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

In the case where a plurality of sipes are inclined in the same direction, there is a problem that an edge effect of the sipe appears in one direction but no edge effect of the sipe occurs in another direction.

In the pneumatic tire according to the third aspect, since the sipes extending from the three different land ends are inclined in directions opposite to each other, the steering wheel of the vehicle equipped with the pneumatic tire is turned. At this time, the edge can be effectively operated even at a moderate angle, and the cornering performance on ice and snow can be improved.

According to a fourth aspect of the present invention, in the pneumatic tire according to the first or second aspect, a plurality of sipes extending from one land portion end all extend in the same direction, and the other sipe extends from the other land portion end. The plurality of extending sipes all extend in the same direction, and the sipe in the land portion has a direction.

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

In the pneumatic tire according to the fourth aspect, a plurality of sipes extending from one land portion end are all extended in the same direction, and a plurality of sipes extending from the other land portion are all extended in the same direction, so that the inside of the land portion is reduced. The sipe has directionality, so the rigid anisotropy in the land can be reduced,
It is possible to suppress unevenness in deformation such that deformation is difficult in one direction and deformation is easy in another direction.

[0022]

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

In FIG. 1, the arrow L and the arrow R
The direction is the tire axial direction, the arrow A direction indicates the tire rotation direction, and the arrow B direction indicates the traveling direction of the tire.

As shown in FIG. 1, the tread 12 (tread width W) of the pneumatic tire 10 of the present embodiment has a circumferential direction extending along the tire circumferential direction on both sides in the tire axial direction with the tire equatorial plane CL interposed therebetween. A wide groove 14 is formed, and a circumferential narrow groove 16 extending substantially along the tire circumferential direction is formed outside the circumferential wide groove 14 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. 1 and the tread end 12R in the direction of the arrow R in FIG. 1 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 formed linearly and are opposite to each other with respect to the tire equatorial plane CL. It is inclined in the direction.

As shown in FIG. 2, 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 °.

In the present embodiment, as shown in FIG.
The transverse groove 18 extending from the tread end 12L on the direction side is inclined so that the tire equatorial plane CL side is located in the direction of arrow B with respect to the tread end 12L side, and the tread end 1 on the side of arrow R direction.
The transverse groove 18 extending from the 2R is inclined so that the tire equatorial plane CL side is located in the direction of the arrow B with respect to the tread end 12R side, and as shown in FIG. ° is set.

In the present embodiment, each transverse groove 18 traverses the circumferential narrow groove 16 and the circumferential wide groove 14, and the axial inner end portion 18 A has a tire circumference formed between the circumferential wide grooves 14. Although it is arranged in the rib-shaped land portion 20 extending continuously along the direction, the present invention is not limited to this, and the transverse groove 18 may be connected to at least the circumferential wide groove 14, The end portion 18A does not necessarily have to be arranged in the rib-shaped land portion 20.

Further, it is preferable that the transverse groove 18 is formed to have a narrower groove width on the inner end portion 18A side in the axial direction than the tread end side 12L, R as in this embodiment.
A straight wall portion 18B and a zigzag portion 18C
Are preferably provided alternately.

The substantially rhombic region surrounded by the circumferential wide groove 14, the circumferential narrow groove 16 and the two transverse grooves 18 has a substantially slanted shape which is inclined with respect to the tire circumferential direction in a direction opposite to the circumferential direction of the tire. A sub-groove 22 having a constant width extending linearly is formed to divide the substantially rhombic region into two, and the sub-groove 22, the circumferential wide groove 14 and the transverse groove 1 are provided inside the sub-groove 22 in the tire axial direction.
8, a substantially land-shaped first land portion 24 is defined, and a substantially trapezoidal second land portion is defined outside the sub-groove 22 in the tire axial direction by the sub-groove 22, the circumferential narrow groove 16 and the transverse groove 18. 26
Is partitioned.

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

As shown in FIG. 2, the inclination angle θ2 formed by the auxiliary groove 22 with respect to the tire circumferential direction is preferably in the range of 30 ° to 70 °, and particularly preferably about 45 °. Secondary groove 2 of the present embodiment
2 is set at 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 the present embodiment is an area between the circumferential narrow grooves 16.

The circumferential narrow groove 16 preferably extends linearly between the transverse grooves 18, and the angle θ3 with respect to the tire circumferential direction is preferably in the range of 0 ° to 20 °. preferable.

As shown in FIG. 2, in this embodiment, the angle θ3 of the circumferential narrow groove 16 with respect to the tire circumferential direction is set to 6 °.

When the angle θ3 of the circumferential narrow groove 16 with respect to the tire circumferential direction is other than 0 °, that is, when the circumferential narrow groove 16 is inclined with respect to the tire circumferential direction, as shown in FIG. The circumferential narrow groove 16 on one side and the circumferential narrow groove 16 on the other side sandwiching the tire equatorial plane CL are grounded from the end of the narrow groove 16 on the tire equatorial plane CL side. Preferably, they are inclined in opposite directions.

Since the rotation direction of the pneumatic tire 10 of this embodiment is in the direction of arrow A, the sub-groove 22 is
The end of the L side is grounded to the road surface.

In the wide circumferential groove 14, the angle θ4 between the axially outer groove wall 14A of the wide circumferential groove 14 and the circumferential direction of the tire is preferably 0 to 20 °. In the pneumatic tire 10 of the present embodiment, the flow of water in the circumferential wide groove 14 when traveling on a wet road surface is in the direction of the arrow B, and the water flows in the circumferential wide groove 14 in the direction of the arrow B and partially flows. Flows to the sub-groove 22, it is preferable that the circumferential wide groove 14 gradually increases in width toward the connecting portion between the circumferential wide groove 14 and the sub-groove 22.

For this reason, in this embodiment, the axially outer groove wall 14A of the wide circumferential groove 14 between the transverse grooves 18 is inclined to connect the circumferential wide groove 14 and the sub-groove 22. The groove width is gradually increased toward the part. In this embodiment, the angle θ4 of the axially outer groove wall 14A is set to 6 °.

A substantially diamond-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.

The rib-shaped land portion 20 has a sipe 32L extending from the end on the arrow L direction side toward the tire equatorial plane CL, and the sipe 32R from the end on the arrow R direction side toward the tire equatorial plane CL. Is extending.

The sipe 32L and the sipe 32 of the present embodiment
R has a zigzag shape.

The sipe 32L is provided with the center line parallel to the transverse groove 18 on the same side.
A center line is provided parallel to the transverse groove 18 on the same side.

As shown in FIG. 2, the end of the sipe 32L on the tire equatorial plane CL side is connected to the middle of the sipe 32R, and the end of the sipe 32R on the tire equatorial plane CL is connected to the middle of the sipe 32L. As a result, the rib-shaped land portion 2
In the central part of the tire 0, a pseudo sipe 34 (the tire equatorial plane CL of the sipe 32L) is bent and extends along the tire equatorial plane CL.
(A part on the tire equatorial plane CL side of the sipe 32R).

The first land portion 24 is provided with a plurality of sipes 36A to 36D, one end of which is connected to the wide groove 14 in the circumferential direction, in parallel with the transverse groove 18, and the sipes 38 each having one end connected to the transverse groove 18.
The sipe 36 is provided to be inclined in the direction opposite to the sipe 36, and the sipe 40 having one end connected to the sub-groove 22 is provided to be inclined in the 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 in 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 each having one end connected to the end on the shoulder side are provided with the transverse grooves 1a.
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 central portion 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. (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, the inclination directions of the transverse grooves 18 are different on both sides of the tire equatorial plane CL, and the inclination directions of the auxiliary grooves 16 are different, so that the tread pattern is a directional pattern. And high wet performance (hydroplaning). (2) Since the pair of circumferentially wide grooves 14 and the pair of circumferentially narrow grooves 16 are provided in the tread 12, high straight running stability and cornering performance on snow can be obtained. (3) 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. (4) High drainage in wet state is obtained by the linear sub-groove 22 bisecting the 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 ground contact surface 60, the groove edge of the sub groove 22 inclined with respect to the tire circumferential direction continuously enters the contact surface, so that high traction during cornering can be obtained.

Further, the cornering performance on ice and snow can be enhanced by the sub-grooves 22 extending inclining with respect to the tire circumferential direction. (5) Since the rib-shaped land portion 20 that is continuous in the tire circumferential direction is provided on the tire equatorial plane CL, the tread 12
Stiffness near the tire equatorial plane CL can be secured,
High braking performance and traction performance mainly on ice can be obtained.

If a block-shaped land portion defined by a lateral groove is formed near the tire equatorial plane CL, the rigidity of the block-shaped land portion in the tire circumferential direction is lower than that of 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. (6) The reason why the straight groove portions 18B and the zigzag portions 18C are alternately provided in the transverse groove 18 is that only the zigzag portions 18C deteriorate the hydroplaning performance at the time of cornering. This is because the linear portions 18B and the zigzag portions 18C are alternately provided to balance the edge components in the horizontal direction, thereby ensuring hydroplaning performance at cornering and improving skid resistance on snow. It is possible to achieve both. (7) Adjust the groove width of the transverse groove 18 to the tread end side 12L, R
Since the inner end portion 18A is narrower than the inner end portion 18A in the axial direction, the negative rate of the tread central section 28 having a relatively high contact pressure can be suppressed low, and high ice braking performance can be obtained. (8) The reason why the inclination angle θ2 of the sub-groove 22 with the circumferential direction of the tire is set in the range of 30 to 70 ° is that the sub-groove 22 (per one) is most likely to rush into the ground contact surface 60 most continuously. This is because

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 and rear and lateral performance are compatible. (9) The reason why the angle θ3 of the circumferential narrow groove 16 with respect to the tire circumferential direction is set within the range of 0 to 20 ° is that when the angle θ3 is 0 °, When the edge component is zero, but near the shoulder portion, that is, in the present embodiment, the uneven wear resistance (so-called heel-and-toe wear) of the third land portion 30 is improved. The axial edge component increases but the third land 3
This is because the uneven wear resistance of No. 0 is slightly reduced.

Therefore, the angle θ3 of the circumferential narrow groove 16
Is set in the range of 0 to 20 °, it is possible to achieve both the securing of the edge component in the tire axial direction and the resistance to uneven wear in the vicinity of the shoulder portion. (10) The angle .theta.4 between the axially outer groove wall 14A of the circumferentially wide groove 14 and the tire circumferential direction is set within the range of 0 to 20 degrees when the angle .theta.4 is 0.degree. Although the edge component of the side groove wall 14A is zero, the uneven wear resistance of the first land portion 24 (so-called heel-and-toe wear resistance) is improved. This is because the edge component increases but the uneven wear resistance of the first land portion 24 slightly decreases.

Therefore, the angle θ4 of the circumferential wide groove 14
Is set within the range of 0 to 20 °, the front and rear edge components and the uneven wear resistance of the first land portion 24 can be compatible. (11) Part of the water in the circumferentially wide groove 14 in the ground contact surface 60 during wet running flows in the direction of the arrow B in the circumferentially wide groove 14 as it is, and another part of the water flows into the sub-groove 22. When the axially outer groove wall 14A of the circumferentially wide groove 14 corresponding to the first land portion 24 is angled as in the present embodiment, the connecting portion between the sub-groove 22 and the circumferentially wide groove 14 is formed. The width of the circumferentially wide groove 14 increases toward the first land portion 24.
The water inside flows smoothly, and drainage during wet running is improved. (12) 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. (13) In the pneumatic tire 10 of the present embodiment, the rib-shaped land portion 20 of the tread 12 has sipes 32L, 32R, the first land portion 24 has sipes 36A to 36C, 38, 40, and the second land portion 26 has Since the sipes 44A to 44D, 46, and 48 and the sipes 52A to D, 54A to C, and 56 are formed on the third land portion 30, high performance on ice and snow as a studless tire can be obtained. (14) The rib-shaped land portion 20 is formed by forming a pseudo sipe 34 that bends 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 the 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. (15) 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. (16) 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. (17) In each land portion, the sipe in the direction of arrow L and the sipe in the direction of arrow R are inclined in directions opposite to each other with respect to the center line of the land portion in the tire axial direction, so that the direction of the sipe in the land portion is increased. As a result, the anisotropy of rigidity in the land portion can be reduced, and unevenness in deformation such as being difficult to deform in one direction and easy to deform in the other direction can be suppressed. 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 edge effect of the sipe appears in one direction but the edge effect of the sipe does not exist in the other direction. (18) 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.

As described above, in the pneumatic tire 10 of the present embodiment, since the pseudo sipes 34, 42, 50, 58 extending along the tire circumferential direction are provided in the land center area, the sipes extending in the tire axial direction are provided. The performance on ice and snow can be greatly improved as compared with a conventional pneumatic tire having a plurality of land portions formed at intervals in the tire circumferential direction. (Other Embodiment 1) A sipe having three or more land ends having different land portions (that is, the land portion is polygonal) and extending from at least three land ends toward the central area of the land portion. Is provided, the sipe extending from each land end may be inclined in directions opposite to each other.

When the sipe extending from each land end is inclined in a direction opposite to each other, when the steering wheel is turned, the sipe edge can work effectively even at a moderate angle, and high cornering on ice and snow can be achieved. Performance is obtained. (Other Embodiment 2) In the above embodiment, the sipes 36, 3
8, 40, 44, 46, 48, 52, 54, and 56 have a zigzag shape, and a continuous shape of the locus of the amplitude center is a straight line. However, the present invention is not limited to this. The continuous shape may be curved.

Sipe 36, 38, 40, 44, 46, 4
When the trajectory of the amplitude center of 8, 52, 54, 56 is curved, the total length of the sipe edge can be longer than when the trajectory is linear, so that the performance on ice and snow (especially braking on ice and traction) is improved. can do. (Test Examples) In order to confirm the effects of the present invention, two types of tires of the embodiment to which the present invention is applied and two types of conventional tires are prepared to provide a feeling on snow, a braking performance on snow, a traction performance on snow, and a feeling on ice. The comparison was made on the braking performance on ice and the wet hydroplaning performance.

Tires of Examples: Tires having the pattern described in the embodiment (tire size: 195 / 65R1)
5) (see FIG. 1). The width of the transverse groove is 8 mm at the end of the tread, 3.5 mm near the 1/4 point, 2.5 mm at the center of the tread, and the groove width of the sub groove is 6.2 mm. In addition,
The quarter point indicates a boundary portion between the outermost region in the tire width direction and the region adjacent to the innermost region when the contact width is divided into four equal parts.

The angle θ 1 of the transverse groove is 70 ° and the angle θ of the sub groove is
2 is 45 °, the angle θ3 of the circumferential narrow groove is 6 °, and the angle θ4 of the axially outer groove wall of the circumferential wide groove is 6 °. All sipe widths are 0.5mm and zigzag amplitude is 1.6m
m, the period is 3.2 mm. The negative rate of the tread is 37.0%.

Conventional Example 1 Tire: As shown in FIG. 3, a circumferential groove 10 extending in a zigzag manner in a plurality of tire circumferential directions.
0, a tire (tire size: 195 / 65R15) in which a large number of block-shaped land portions 106 defined by a circumferential groove 102 extending linearly and a lateral groove 104 extending in the tire axial direction are provided on a tread 108; In 106, a plurality of sipes 110 extending linearly along the tire axial direction are formed at substantially equal intervals in the tire circumferential direction.

The circumferential groove 100 has a groove width of 7 mm and the circumferential groove 1
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%.

Conventional Example 2 Tire: As shown in FIG. 4, the tire has the same pattern as that of the example, and on one side of the tire equatorial plane CL, the sipes 112 are all inclined in the same direction at the same angle. 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.

[0069]

[Table 1]

As a result of the test, the tire according to 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, a braking performance on ice and a wet hydroplaning as compared with the conventional tire. Performance improved for all of the performances.

[0071]

As described above, in the pneumatic tire of the present invention, a plurality of block-like land portions defined by a plurality of intersecting grooves are formed on the tread tread portion, and one end of the land portion from the end of one tread portion. The extended sipe and the sipe extending from the other land end are connected at the center of the land to form a pseudo-sipe having a plurality of bent shapes extending along the circumferential direction of the tire at the center of the land. Since the density is increased, an edge effective for improving the braking performance on ice and the traction performance on ice can be formed, the rigidity around the land can be secured, and high performance on ice and snow can be obtained.

Further, since the pseudo sipes extend in the tire circumferential direction, the pseudo sipes have an excellent effect that a high cornering performance on ice and snow can be obtained.

[Brief description of the drawings]

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

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

FIG. 3 is a plan view of a tread of a pneumatic tire of Conventional Example 1.

FIG. 4 is a plan view of a tread of a pneumatic tire of Conventional Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pneumatic tire 12 Tread (tread portion) 14 Circumferentially wide groove 16 Circumferentially narrow groove 18 Crossing groove 22 Secondary groove 24 First land portion 26 Second land portion 30 Third land portion 36 Sipe 38 Sipe 40 sipes 42 pseudo sipes 44 sipes 46 sipes 48 sipes 50 pseudo sipes 52 sipes 54 sipes 56 sipes 58 pseudo sipes

Claims (4)

[Claims] 1. A pneumatic tire including a plurality of block-shaped land portions defined by a plurality of intersecting grooves on a tread tread portion, and a plurality of sipes on the land portion. A sipe extending from each of at least two land ends toward the central area of the land and extending from one land end and a sipe extending from the other land end are opposite to each other. And a sipe extending from one land end is connected to an intermediate part of a sipe extending from the other land end, and a sipe extending from the other land end is connected from one land end. A pneumatic tire, wherein a pseudo sipe extending substantially along the tire circumferential direction is formed in the central area by being connected to an intermediate portion of the extending sipe. 2. The pneumatic tire according to claim 1, wherein the sipe is bent a plurality of times. 3. The sipe comprises at least three of the land portions.
3. A sipe extending from one land end toward a central area of the land, wherein the sipes extending from each land end are inclined in opposite directions to each other. Pneumatic tires. 4. A plurality of sipes extending from one land end all extend in the same direction, a plurality of sipes extending from the other land end all extend in the same direction, and a sipe in the land has directionality. The pneumatic tire according to claim 1 or 2, wherein: