JP6487797B2 - tire - Google Patents

Description

  The present invention relates to a tire capable of suppressing deformation of a block at the time of ground contact.

  For example, Patent Document 1 below proposes a tire in which a block is provided with a plurality of sipes extending in the tire axial direction. In this tire, in order to suppress a decrease in rigidity of the end portion of the block in the tire circumferential direction, a pair of first sipe depths arranged on both outer sides in the tire circumferential direction of the block are provided between them. It is configured to be smaller than the sipe depth. Further, the first sipe and the second sipe include a periodic pattern portion that swings in the tire circumferential direction toward the inner side in the tire radial direction. In the periodic pattern portion, a plurality of corner portions that are convex on one side or the other side in the tire circumferential direction are formed. The sipe having such a corner portion is expected to have an effect that the sipe walls facing each other mesh with each other when the ground pressure and shearing force are applied to the block, thereby suppressing the collapse of the block.

  However, in the tire of Patent Document 1, since the first sipe is formed with a depth smaller than that of the second sipe, the number of corner portions of the first sipe is smaller than the number of corner portions of the second sipe. Therefore, such a first sipe has a problem that the above-described collapse cannot be sufficiently suppressed at the end of the block.

JP 2012-401024

  The present invention has been devised in view of the above problems, and is based on the improvement of the sipe depth and the wavelength of the periodic pattern portion, and a tire capable of effectively suppressing block deformation. The main purpose is to provide.

  The present invention is a tire in which a plurality of blocks are formed in a tread portion, and at least one of the blocks is provided with a plurality of sipes extending in a tire axial direction, and the sipes are formed of the blocks. A pair of first sipes disposed on both outer sides in the tire circumferential direction, and at least one second sipe disposed between the pair of first sipes and having a depth greater than the first sipes. In the block longitudinal cross-section along the tire circumferential direction, the first sipe and the second sipe include a periodic pattern portion that oscillates in the tire circumferential direction toward the inner side in the tire radial direction, and the periodic pattern of the second sipe The portion has a second wavelength, and the periodic pattern portion of the first sipe has a first wavelength smaller than the second wavelength.

  In the tire according to the present invention, in the block longitudinal section, each of the first sipe and the second sipe has a plurality of corner portions that are convex on one side or the other side in the tire circumferential direction. The number of the corner portions is preferably equal to or greater than the number of the corner portions of the second sipe.

  In the tire according to the present invention, it is preferable that the periodic pattern portion of the second sipe has a second amplitude, and the periodic pattern portion of the first sipe has a first amplitude smaller than the second amplitude. .

  In the tire according to the aspect of the invention, it is preferable that the first sipe is similar to the second sipe in the block longitudinal section.

  In the tire according to the aspect of the invention, it is preferable that the sipe includes a plurality of the second sipes, and each of the plurality of second sipes has the same depth.

  The sipe provided in the block of the tire of the present invention includes a pair of first sipes disposed on both outer sides in the tire circumferential direction of the block, and a depth greater than the first sipes disposed between the pair of first sipes. And at least one second sipe having a thickness. The first sipe and the second sipe increase the traction performance on ice by the edge effect, and suppress a decrease in rigidity at both ends of the block in the tire circumferential direction.

  In the longitudinal section of the block along the tire circumferential direction, the first sipe and the second sipe include a periodic pattern portion that swings in the tire circumferential direction toward the inside in the tire radial direction. In such first and second sipes, when contact pressure and shearing force are applied to the block, the facing sipe walls mesh with each other to suppress excessive deformation and collapse of the block, thereby improving running performance. .

  The periodic pattern portion of the second sipe has a second wavelength, and the periodic pattern portion of the first sipe has a first wavelength that is smaller than the second wavelength. Thereby, even if the depth of the 1st sipe is comprised smaller than the depth of the 2nd sipe, the reduction | decrease in the number of the corner parts which protrudes in the 1st sipe to the one side or the other side of a tire circumferential direction is suppressed. Is done. Accordingly, the collapse of the block near the first sipe is effectively suppressed.

It is an expanded view of the tread part of the pneumatic tire of one embodiment of the present invention. It is an enlarged view of the block of FIG. It is the sectional view on the AA line of FIG. It is an expanded sectional view of the 1st sipe and the 2nd sipe of FIG. It is sectional drawing of the conventional sipe. It is a perspective view of the sipe wall of a 2nd sipe. (A) And (b) is sectional drawing which shows the sipe of other embodiment of this invention. It is sectional drawing which shows the sipe of other embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a development view of the tread portion 2 of the tire 1 of the present embodiment. The tire 1 of the present embodiment is suitably used as a winter passenger car tire, for example.

  As shown in FIG. 1, the tread portion 2 of the tire 1 of the present embodiment includes, for example, a plurality of vertical grooves 3 extending in the tire circumferential direction, a plurality of horizontal grooves 4 extending in the tire axial direction, A plurality of blocks 5 divided by the lateral grooves 4 are formed. The block 5 of this embodiment has, for example, a rectangular tread. However, the shape of the tread surface of the block 5 is not limited to such a mode.

  FIG. 2 shows an enlarged view of the block 5. As shown in FIG. 2, at least one of the blocks 5 is provided with a plurality of sipes 10 extending in the tire axial direction.

  Each sipe 10 of the present embodiment extends, for example, in a zigzag shape in the tire axial direction in a tread plan view. Each sipe 10 may extend linearly in the tire axial direction in a tread plan view.

  The sipe 10 includes a pair of first sipes 11 and 11 disposed on both outer sides in the tire circumferential direction of the block 5, and at least one second sipe 12 disposed between the pair of first sipes 11 and 11. Is included. Each of these sipes enhances traction performance on ice due to, for example, an edge effect.

  Although at least one second sipe 12 is provided between the first sipes 11, 11, a plurality of second sipe 12 is preferably provided. In the present embodiment, three second sipes 12 are provided.

  FIG. 3 is a cross-sectional view taken along line AA in FIG. 2 as a block vertical cross section along the tire circumferential direction. As shown in FIG. 3, the first sipe 11 has a depth d1. The second sipe 12 has a depth d2 that is greater than the depth d1 of the first sipe 11. Thereby, since the depth of the 1st sipe 11 becomes relatively small, the 1st sipe 11 is harder to open than the 2nd sipe 12. Accordingly, the block 5 prevents a decrease in rigidity at both ends in the tire circumferential direction, and for example, heel and toe wear is suppressed.

  Although not particularly limited, a ratio d1 / d2 between the depth d1 of the first sipe 11 and the depth d2 of the second sipe 12 is preferably 0.6 to 0.8, for example. This suppresses uneven wear at both ends of the block while obtaining excellent traction on ice.

  For example, the second sipes 12 of the present embodiment have the same depth. Thereby, the rigidity distribution of the center part of the block 5 becomes uniform, and uneven wear of the block 5 is suppressed.

  The first sipe 11 and the second sipe 12 include a periodic pattern portion 15 that swings in the tire circumferential direction toward the inner side in the tire radial direction in a block longitudinal section along the tire circumferential direction. In the present embodiment, the first sipe 11 and the second sipe 12 have an amplitude in a zigzag shape, but are not limited to such an aspect, and may be an amplitude in a sinusoidal shape, for example. Moreover, in this embodiment, although the 1st sipe 11 and the 2nd sipe 12 are comprised only from the periodic pattern part 15, for example, even if the non-periodic pattern part extended along a tire radial direction is included in the one end side good. Each of the first sipe 11 and the second sipe 12 includes a plurality of corner portions 16 that are convex on one side or the other side in the tire circumferential direction by including the periodic pattern portion 15.

  When the ground pressure and the shearing force are applied to the block 5, the first sipe 11 and the second sipe 12 can be engaged with each other to suppress excessive deformation and collapse of the block, thereby improving running performance. .

  FIG. 4 shows an enlarged cross-sectional view of the first sipe 11 and the second sipe 12 of FIG. As shown in FIG. 4, the periodic pattern portion 15b of the second sipe 12 has a second wavelength λ2. On the other hand, the periodic pattern portion 15a of the first sipe 11 has a first wavelength λ1 that is smaller than the second wavelength λ2.

  Conventionally, when a plurality of sipes having a periodic pattern portion and different depths are formed, as shown in FIG. 5, the periodic pattern portions of each sipe have the same wavelength and only the depth. It was changed and formed. In general, when a plurality of sipe having a periodic pattern portion and different depths are formed, one type of knife blade corresponding to the deepest sipe is used as a sipe forming knife blade attached to a vulcanization mold. Are prepared, and this knife blade is cut and used for a sipe having a small depth. Therefore, in a conventional tire, a sipe having a small depth has a tendency that the number of corner portions 16 that help to suppress the shear deformation of the block is reduced, and that both end portions of the block are particularly greatly collapsed when the block is grounded. .

  On the other hand, as shown in FIG. 4, the first wavelength λ1 of the first sipe 11 of the present embodiment is smaller than the second wavelength λ2 of the second sipe 12, so that the depth d1 of the first sipe 11 is Even when it is formed to be smaller than the depth d2 of the second sipe 12, a decrease in the number of corner portions 16 is suppressed. Accordingly, the collapse of the block near the first sipe 11 is effectively suppressed.

  In order to exhibit the above-described effect, the ratio λ1 / λ2 between the first wavelength λ1 and the second wavelength λ2 is preferably 0.6 to 0.8, for example.

  The number of corner portions 16 of the first sipe 11 is preferably the same as the number of corner portions 16 of the second sipe 12. Alternatively, as shown in FIG. 8, the number of corner portions 16 of the first sipe 11 is preferably larger than the number of corner portions 16 of the second sipe 12. Thereby, falling of the edge part of the block 5 is suppressed effectively.

  As shown in FIG. 4, the first amplitude A1 of the periodic pattern portion 15a of the first sipe 11 and the second amplitude A2 of the periodic pattern portion 15b of the second sipe 12 are, for example, 2.0 to 5.0 mm. It is. When the first amplitude A1 and the second amplitude A2 are smaller than 2.0 mm, the block may be easily deformed. When the first amplitude A1 and the second amplitude A2 are greater than 5.0 mm, the block may be cracked when the sipe forming knife blade is pulled out from the block after vulcanization.

  When the first amplitude A1 and the second amplitude A2 are equal, there is a possibility that a block breaks on the first sipe 11 side when the knife blade is pulled out. For this reason, it is desirable that the first amplitude A1 is smaller than the second amplitude A2. Specifically, the first amplitude A1 is preferably 0.65 to 0.80 times the second amplitude A2, for example. Thereby, the crack of a block is suppressed effectively.

  As a more desirable aspect, in the present embodiment, the first sipe 11 is similar to the second sipe 12 in the block longitudinal section. Thereby, the deformation | transformation in the edge part of the block 5 is suppressed more effectively.

  As shown in FIG. 2, the first sipe 11 and the second sipe 12 of the present embodiment are, for example, full open sipes that cross the block 5. Such first sipe 11 and second sipe 12 exhibit an excellent edge effect on ice. However, the first sipe 11 may be a closed sipe whose one end or both ends terminate in the block. Such a first sipe 11 is useful for suppressing the collapse at the end of the block 5.

  The minimum distance L2 in the tire circumferential direction between the first sipe 11 and the edge 17 in the tire axial direction of the block 5 is preferably 0.05 times or more of the length L1 in the tire circumferential direction of the block 5, more preferably 0. It is 08 times or more, preferably 0.15 times or less, more preferably 0.12 times or less. Such a 1st sipe 11 exhibits the outstanding edge effect, suppressing the fall of the edge part of the block 5. FIG.

  The distance L3 in the tire circumferential direction between the first sipe 11 and the second sipe 12 is preferably 0.10 times or more, more preferably 0.15 times or more, preferably 0.15 times or more the length L1 of the block 5. 25 times or less, more preferably 0.20 times or less. Thereby, the outstanding edge effect is exhibited while the rigidity of the block piece between the 1st sipe 11 and the 2nd sipe 12 is maintained.

  FIG. 6 is a perspective view of the sipe wall of the second sipe 12 as a diagram for explaining the shape of the sipe wall of each sipe 10. As shown in FIG. 6, the sipe wall of each sipe 10 is preferably formed in a so-called Miura fold shape, for example. In other words, in the sipe 10 of the present embodiment, the opening edge shape that opens at the tread surface of the block has the zigzag-shaped portion 18, and the opening edge shape is substantially retained in the depth direction, The zigzag portion 18 is displaced in the length direction of the sipe 10. Moreover, the displacement of the zigzag portion 18 changes its direction at the corner portion 16.

  In the sipe 10 having such a Miura-folded wall surface, the wall surfaces of the sipe can be more strongly engaged with each other, and the rigidity of the block can be maintained.

  FIGS. 7A and 7B are longitudinal sectional views of blocks according to other embodiments of the present invention. As shown in FIG. 7A, the sipe 10 of this embodiment includes, for example, a first sipe 11 between a pair of first sipe 11 and 11 arranged on both outer sides of the block 5 in the tire circumferential direction. A second sipe 12 having a greater depth and a third sipe 13 having the same depth as the first sipe 11. Such a sipe arrangement can further suppress deformation of the block 5 because the third sipe 13 having a relatively small depth is provided.

  In the embodiment shown in FIG. 7B, the second sipes 12a and 12b having different depths are provided between the pair of first sipes 11 and 11 disposed on both outer sides of the block 5 in the tire circumferential direction. It has been. Such a sipe arrangement is useful for suppressing deformation on one side (left side in FIG. 7B) of the block piece between the second sipes 12a and 12b in the tire circumferential direction. Such a sipe arrangement can improve traction performance or braking response.

  As mentioned above, although the tire of one embodiment of the present invention was explained in detail, the present invention is not limited to the above-mentioned specific embodiment, and can be carried out by changing to various modes.

A tire having a size of 195 / 65R15 having the basic tread pattern of FIG. 1 and the blocks shown in FIG. 3 or the sipes shown in FIG. Prototype. As a comparative example, as shown in FIG. 5, the wavelengths of the first sipe and the second sipe are the same, and the number of corner portions of the first sipe is smaller than the number of corner portions of the second sipe. A tire was prototyped. Each test tire was tested for dry performance, wear resistance, and ice braking performance. The common specifications and test methods for each test tire are as follows.
Rims: 15 × 6.0J
Tire internal pressure: 240kPa
Test vehicle: displacement 1600cc, front wheel drive vehicle Test tire mounting position: all wheels

<Dry performance>
The driving performance on the dry asphalt road surface of the test vehicle equipped with each test tire was evaluated by the driver's sensuality. A result is a score which makes the comparative example 100, and shows that dry performance is excellent, so that a numerical value is large.

<Abrasion resistance>
The amount of wear of the block when the test vehicle traveled a certain distance was measured. The result is the reciprocal of the amount of wear, and is displayed as an index with the comparative example being 100. It shows that it is excellent in abrasion resistance, so that a numerical value is large.

<Brake performance on ice>
The braking distance when the test vehicle entered the icy road at a constant speed and suddenly braked was measured. The result is the reciprocal of the braking distance, and is represented by an index that is Comparative Example 100. The larger the value, the better the braking performance on ice.
The test results are shown in Table 1.

  As a result of the test, it was confirmed that the tire of the example improved the dry performance, the wear resistance, and the on-ice brake performance in a well-balanced manner by suppressing the deformation of the block.

2 tread portion 5 block 10 sipe 11 first sipe 12 second sipe 15 periodic pattern portion λ1 first wavelength λ2 second wavelength

Claims (5)

A tire having a plurality of blocks formed in a tread portion,
At least one of the blocks is provided with a plurality of sipes extending in the tire axial direction,
The sipe is a pair of first sipe disposed on both outer sides in the tire circumferential direction of the block, and at least one sipe disposed between the pair of first sipe and having a depth greater than that of the first sipe. And the second sipe of
In the block longitudinal section along the tire circumferential direction, the first sipe and the second sipe include a periodic pattern portion that swings in the tire circumferential direction toward the inside in the tire radial direction,
The tire according to claim 1, wherein the periodic pattern portion of the second sipe has a second wavelength, and the periodic pattern portion of the first sipe has a first wavelength smaller than the second wavelength. In the block longitudinal section, each of the first sipe and the second sipe has a plurality of corner portions that are convex on one side or the other side in the tire circumferential direction,
2. The tire according to claim 1, wherein the number of the corner portions of the first sipe is equal to or greater than the number of the corner portions of the second sipe. The periodic pattern portion of the second sipe has a second amplitude;
The tire according to claim 1 or 2, wherein the periodic pattern portion of the first sipe has a first amplitude smaller than the second amplitude.   The tire according to any one of claims 1 to 3, wherein the first sipe is similar to the second sipe in the block longitudinal section. The sipes include a plurality of the second sipes,
The tire according to any one of claims 1 to 4, wherein each of the plurality of second sipes has the same depth.