JP5529998B1 - tire - Google Patents

Abstract

A tire capable of improving high traction performance over a long period of time is provided.
A tire is provided with a tread having a plurality of blocks, and a plurality of blocks out of the plurality of blocks are provided with protrusions 11 extending outward in the tire radial direction. The step portion 12 is formed. The protrusion 11 has a first recess 13 formed in at least a part of the adjacent position, and the height c of the step surface of the step portion 12 is lower than the height b of the step surface of the block peripheral edge. The outer edge shape of the tread surface of the protrusion 11 and the outer edge shape of the tread surface of the stepped portion 12 are both polygonal.
[Selection] Figure 2

Description

  The present invention relates to a tire including a tread in which a plurality of blocks are formed, and at least some of the plurality of blocks having protrusions extending outward in the tire radial direction.

  2. Description of the Related Art A technique for forming a protrusion on a tread surface of a block is known for a tire for a motorcycle for running on rough terrain, particularly in a muddy area (see, for example, Patent Document 1). According to this technique, the traction performance can be improved by enhancing the edge effect by the protrusion.

JP 2009-196425 A

  By the way, in the tire as described above, the ground pressure is concentrated on the edge portion of the protrusion during running, so that the edge portion is worn and rounded, and the edge effect of the protrusion is lowered and the traction performance is improved. Cannot be expected. As described above, it is difficult to improve the high traction performance over a long period of time in the conventional tire in which the protrusion is formed on the tread surface of the block.

The tire according to the present invention includes a tread having a plurality of blocks, and a plurality of blocks out of the plurality of blocks having protrusions extending outward in a tire radial direction. A step portion is formed, and a first recess is formed in at least a part of the position adjacent to the protrusion .
According to this tire, after the wear of the edge of the protrusion has progressed, the edge portion of the stepped portion exhibits a new edge effect, whereby high traction performance can be improved over a long period of time. In addition, the formed first recess improves the edge effect and provides traction.
Performance, and by making the protrusions easy to move and follow the road surface shape,
The control performance can be improved by improving the earth property.

Furthermore, in the tire of the present invention, it is preferable that the height of the tread surface of the stepped portion is lower than the height of the tread surface of the block peripheral portion.
In this case, by reducing the height of the tread on the stepped portion of the protrusion and delaying the wear of the edge portion of the stepped portion, the stepped portion exhibits an edge effect even after the wear of the protrusion has advanced, and the traction Performance can be improved.
In this specification, the block peripheral portion of the block in which the protrusion is formed is defined as a step including a step portion and a protrusion including a second recess (when a second recess described later) is formed from the block, The part inside the tire radial direction from the protrusion and the part excluding the part inside the tire radial direction from the first concave part (when the first concave part is formed) shall be said.
Further, in this specification, the “height” of the tread surface of the stepped portion of the protrusion, the block peripheral edge portion, and the protrusion refers to the height in the tire radial direction from the base end of the protrusion.

In the tire according to the present invention, the shape of the outer edge of the tread surface of the protrusion and the shape of the outer edge of the tread surface of the stepped portion are polygons having at least a side extending in the tire width direction and a side extending in the tire circumferential direction. It is preferable that
In this case, the edge effect can be improved by making the shape of the outer edge of the tread surface of the protrusion and the tread surface of the step portion polygonal. In addition, these outer edges have sides extending in the tire width direction, so that traction performance during straight traveling can be improved, while those having edges extending in the tire circumferential direction improve traction performance during turning. be able to.
In this specification, the “tread surface” refers to a surface that faces the outer side in the tire radial direction and can be grounded when a new or worn tire is used.

And in the tire of this invention, it is preferable that the area of the tread of the said level | step-difference part is smaller than the area of the tread of the said protrusion.
In this case, by sufficiently securing the area of the tread surface of the protrusion, it is possible to ensure the grounding property and the control performance, and to secure the rigidity of the protrusion and improve the traction performance.

In the tire of the present invention, it is preferable that the tread is composed of rubber having a JIS A hardness of 55 or more.
In this case, the edge effect of the block can be enhanced to improve the traction performance, and the wear resistance of the block can be improved.

  According to the tire according to the present invention, high traction performance can be improved over a long period of time.

It is a partial top view which shows one Embodiment of the tire of this invention. It is the tire width direction sectional drawing which cut | disconnected the tire of FIG. 1 by the II line. FIG. 2 is an enlarged view showing a periphery of a protrusion formed on a center block of the tire of FIG. 1.

Hereinafter, embodiments of a tire according to the present invention will be described by way of example with reference to the drawings.
The tire according to one embodiment of the present invention shown in FIG. 1 is a motorcycle tire, in the vicinity of the tire equatorial plane CL of the tread, a first center block 10a, a second center block 10b, a third center block 10c, The fourth center block 10d and the fifth center block 10e are arranged at intervals in the tire circumferential direction to form a center block row.
The first intermediate block 20a, the second intermediate block 20b, the third intermediate block 20c, and the fourth intermediate block 20d are arranged at intervals in the tire circumferential direction on both sides of the center block row in the tire width direction. Thus, an intermediate block row is formed.
Further, the first shoulder block 30a, the second shoulder block 30b, the third shoulder block 30c, the fourth shoulder block 30d, and the fifth shoulder block 30e are spaced apart in the tire circumferential direction on both sides in the tire width direction of the intermediate block row. They are arranged at intervals to form a shoulder block row.

  Each of the first to fifth center blocks 10a to 10e has a substantially rectangular shape having a long side in the tire width direction. A relatively wide shallow groove 19 extending in the tire circumferential direction is formed at the center in the tire width direction of the second to fourth center blocks 10b to 10d. In addition, the tire radial direction depth dimension of the shallow groove | channel 19 is smaller than the tire radial direction height of the 1st-5th center blocks 10a-10e.

As shown in FIG. 1 and the second center block 10b on both sides of the tread surface of the first to fifth center blocks 10a to 10e in the tire width direction center, rectangular projections 11 in a tread plan view are shown. Is formed. As shown in FIG. 3, a step portion 12 having a rectangular outer edge on the tread surface in a tread plan view is formed on at least a part of the side surface of the protrusion 11.
A first recess 13 is disposed between and around the two protrusions 11 of the first and fifth center blocks 10 a and 10 e, and a block peripheral edge 10 s is formed around the first recess 13. ing. The 1st recessed part 13 becomes a groove | channel between the two protrusions 11 and block peripheral part 10s. In the second to fourth center blocks 10 b to 10 d, a first recess 13 is formed around each of the two protrusions 11, and a block peripheral edge 10 s is formed around the first recess 13. The 1st recessed part 13 becomes a groove | channel between each protrusion 11 and block peripheral part 10s.
The outer edge of the tread surface of the protrusion 11 of the first to fifth center blocks 10a to 10e and the outer edge of the tread surface of the stepped portion 12 have sides extending in the tire width direction and sides extending in the tire circumferential direction.
And the corner | angular part (edge part) is formed in the outer periphery and inner periphery of the block peripheral part 10s of the 1st-5th center blocks 10a-10e, the outer edge of the tread of the level | step-difference part 12, and the outer edge of the tread of the processus | protrusion 11. . The same applies to the intermediate block row and the shoulder block row.
Although not shown, two or more step portions can be provided on at least a part of the side surface of the protrusion.

  The first to fourth intermediate blocks 20a to 20d are formed to be smaller than the blocks of the center blocks 10a to 10e, and have a substantially rectangular shape in a tread plan view. The first to fourth intermediate blocks 20a to 20d are formed with rectangular protrusions 21 in a tread plan view. Although not shown, a step portion having a rectangular outer edge in a plan view of the tread is formed on at least a part of the side surface of the protrusion 21. A first recess 23 is formed around the protrusion 21, and a block peripheral edge 20 s is formed around the first recess 23. The outer edge of the tread surface of the protrusion 21 of the first to fourth intermediate block 20a to 20d and the outer edge of the tread surface of the stepped portion have sides extending in the tire width direction and sides extending in the tire circumferential direction.

  The first to fifth shoulder blocks 30a to 30e are hexagonal in a tread plan view. Projections 31 are formed on the first to fifth shoulder blocks 30a to 30e. Although not shown, at least a part of the side surface of the protrusion 31 is formed with a step portion similar to the step portion 12 described above. A first recess 33 is formed around the protrusion 31, and a block peripheral edge 30 s is formed around the first recess 33. Both the outer edge of the tread surface of the protrusion 31 of the first to fifth shoulder blocks 30a to 30e and the outer edge of the tread surface of the stepped portion have a shape substantially similar to the shape of the outer edge of the block.

From here, the behavior of the block when using the tire will be described by taking the second center block 10b as an example. The other blocks have the same behavior.
In the tire of this embodiment, when the tire is new, the protrusion 11 and the block peripheral edge portion 10s are grounded. Therefore, both the edge part of the protrusion 11 and the edge part of the block peripheral part 10s exhibit an edge effect particularly when traveling on rough terrain. Here, as shown in FIG. 2, when the height of the tread of the block peripheral portion 10s is a and the height of the tread of the protrusion 11 is b,
It is preferable that −2 mm ≦ a−b <2 mm for grounding both the protrusion 11 and the block peripheral portion 10 s during use.

  Next, during traveling, the edge portion of the protrusion 11 and the edge portion of the block peripheral portion 10s are worn and rounded by the contact pressure, and the height a of the tread surface and the protrusion 11 of the block peripheral portion 10s shown in FIG. The height b of the tread is gradually lowered.

When the above-described wear progresses, the height a of the tread surface of the block peripheral portion 10s becomes equal to or less than the height c of the tread surface of the step portion 12 formed on the side surface of the protrusion 11, and the tread surface of the step portion 12 blocks. It comes to be located on the outer side in the tire radial direction from the tread surface of the peripheral portion 10s. Thereby, the edge part of the level | step-difference part 12 will exhibit an edge effect.
That is, after the block wear progresses, the edge portion of the protrusion 11 and the edge portion of the block peripheral portion 10s are worn and rounded, so that these edge effects are reduced, but the step portion 12 is worn. The edge portion that is not present exhibits a new edge effect. For this reason, even if the block is worn, the edge effect is maintained, and the traction performance can be improved over a long period of time.
In addition, like this embodiment, the level | step-difference part 12 is higher by providing the level | step-difference part 12 in the block row | line | column (center block row | line | column) nearest to the tire equator surface CL which is an area | region where the contact pressure is the highest at least. Traction performance can be demonstrated.

Moreover, in this embodiment, as shown in FIGS. 1-3, the 1st recessed part 13 adjacent to the processus | protrusion 11 is formed between the processus | protrusion 11 and block peripheral part 10s. As a result, the edge effect can be exerted on the inner peripheral edge of the block peripheral edge portion 10s to improve the traction performance, and the protrusion 11 can be easily moved to improve the grounding performance and the control performance can be improved.
The height c of the step surface of the step portion 12 of the protrusion 11 is more preferably smaller than the height d from the step surface of the step portion 12 to the step surface of the protrusion 11. Thus, by providing the step portion 12 at a low position, the rigidity of the protrusion 11 can be further reduced and the grounding property can be further improved.

  Further, the height c of the tread surface of the step portion 12 of the protrusion 11 is made lower than the height a of the tread surface of the block peripheral portion 10s, and the wear of the step portion 12 is suppressed until the wear of the protrusion 11 proceeds. After the 11 wear progresses, the stepped portion 12 can sufficiently exhibit the edge effect and maintain the traction performance. Note that c can be set to 1 to 2 mm, for example, and a to c can be set to about 1 mm, for example.

And as shown in FIG. 3, while making the shape of the outer edge of the tread surface of the protrusion 11 into a polygon (a quadrangle in the figure) having a side 11a extending in the tire width direction and a side 11b extending in the tire circumferential direction, The shape of the outer edge of the tread surface of the portion 12 is preferably a polygon (rectangle in the drawing) having a side 12a extending in the tire width direction and a side 12b extending in the tire circumferential direction.
In this case, the edge effect can be improved by making the outer edge shapes of the tread surface of the protrusion 11 and the tread surface of the stepped portion 12 polygonal. In addition, the outer edge has a side extending in the tire width direction, so that the traction performance during straight traveling can be improved. On the other hand, the outer edge has a side extending in the tire circumferential direction to improve the traction performance during turning. Can do.

Here, it is preferable that the area of the tread surface of the step portion 12 is smaller than the area of the tread surface of the protrusion 11.
In this case, by sufficiently securing the area of the tread surface of the protrusion 11, it is possible to ensure the grounding property and the control performance, and also ensure the rigidity of the protrusion 11 to ensure the traction performance. it can.

By the way, it is preferable that the tread is made of rubber having a JIS A hardness of 55 or more. In this case, the edge effect of the block can be enhanced to improve the traction performance, and the wear resistance of the block can be improved.
In the tire according to this embodiment, the stepped portion is formed on the side surface of the protrusion, so that the tread surface of the block can be moved easily to improve the ground contact. Therefore, sufficient grounding property can be ensured even if rubber having high hardness is used for the tread.
Further, it is preferable that the tread is composed of rubber having a JIS A hardness of 80 or less. If the JIS A hardness of the rubber is higher than 80, the ground contact property may be lowered.

  Moreover, in this embodiment, as shown in FIG. 1, the 2nd recessed part 24 is formed in the center part of the processus | protrusion 21 of the 1st-4th intermediate | middle part block 20a-20d. And the corner | angular part (edge part) is formed in the outer edge upper end of a 2nd recessed part. Thereby, the edge effect of the protrusion 21 can be improved and the traction performance can be further improved, and the control performance can be improved by reducing the rigidity of the surface of the protrusion 21 and improving the ground contact.

Bias tires and radial tires were prototyped and their performance was evaluated, and will be described below.
The prototyped bias tires are 120 / 80-19 and 110 / 90-19 in size, and have two layers of nylon carcass plies and one layer of nylon breakers.
The prototyped radial tire has tire sizes of 120 / 80R19 and 110 / 90R19, and includes two layers of nylon carcass plies and one layer of Kevlar belt.

For each of the bias tire and the radial tire, Example tires 1 and 2 and Comparative tires 1 and 2, which will be described below, were prototyped.
The example tires 1 and 2 have the tread patterns shown in FIGS. 1 to 3, each block has a protrusion, and a step is formed on a side surface of each protrusion. Moreover, the 1st recessed part is formed adjacent to the processus | protrusion of each block. And the shape of the outer edge of the tread of the projection of each block and the shape of the outer edge of the tread of the stepped portion are rectangular shapes having sides extending in the tire width direction and sides extending in the tire circumferential direction. The height of the tread on the stepped portion of the protrusion is lower than the height of the tread on the peripheral edge of the block. Further, the rubber constituting the tread has a JIS A hardness of 55.

In the comparative example tire 1, the first concave portion similar to the example tire 1 is formed on the tread surface of each block, but no protrusion is formed. About other points, it is the same as Example tire 1.
The comparative example tire 2 has the same first recesses and projections as the example tire 1 on the tread surface of each block, but no stepped portions are formed on the side surfaces of the projections. About other points, it is the same as Example tire 1.

Each of the prototype tires is mounted on a motorcycle, and a professional motocross rider runs a motocross competition course for 100 km, and the initial (new) and after wear, traction performance at the time of going straight and turning is perfect. Evaluation was performed by evaluating.
As a result of the test, no difference was found between the bias tire and the radial tire in any of the example tire 1 and the comparative example tires 1 and 2. Further, in the example tire 1, the height of the stepped surface of the stepped portion is lower than the height of the block peripheral portion, and in the example tire 2, the height of the stepped surface of the stepped portion is equal to or higher than the height of the block peripheral portion. The results are shown in Table 1.

  From the results shown in Table 1, it is clear that Example Tires 1 and 2 have significantly improved traction performance after wear while exhibiting equivalent or higher initial traction performance than Comparative Tires 1 and 2. Became. Further, the example tire 1 in which the height of the stepped portion is lower than the height of the tread on the block peripheral portion is higher than that of the example tire 2 in which the height of the stepped portion is equal to or higher than the height of the tread on the block peripheral portion. It became clear that the traction performance was high.

10a-10e: 1st-5th center block, 10s: Block peripheral part,
11: Projection, 12: Stepped portion, 13: First recess, 19: Shallow groove,
20a-20d: 1st-4th intermediate part block, 21: Protrusion, 23: 1st recessed part,
24: 2nd recessed part, 20s: Block peripheral part,
30a-30e: 1st-5th shoulder block, 31: Protrusion, 33: 1st recessed part,
30 s: block periphery, a: height of tread on block periphery,
b: height of the tread on the protrusion, c: height of the tread on the step,
d: Height from the tread of the step to the tread of the protrusion, CL: tire equator

Claims (5)

It has a tread with multiple blocks,
A tire in which a plurality of blocks out of the plurality of blocks have protrusions extending outward in the tire radial direction,
A step is formed on the side surface of the protrusion ,
The tire is characterized in that a first recess is formed in at least a part of a position adjacent to the protrusion . The tire according to claim 1, wherein a height of a step surface of the stepped portion is made lower than a height of a step surface of a block peripheral portion . The shape of the outer edge of the tread surface of the protrusion and the shape of the outer edge of the tread surface of the stepped portion are polygons having at least sides extending in the tire width direction and sides extending in the tire circumferential direction. Tire described in . The tire according to any one of claims 1 to 3, wherein an area of a tread surface of the step portion is smaller than an area of a tread surface of the protrusion . The tire according to any one of claims 1 to 4, wherein the tread is made of rubber having a JIS A hardness of 55 or more .

Images