JP3938809B2 - Pneumatic tire - Google Patents

Description

【００３２】
操縦安定性試験は、実車に各空気入りタイヤを装着し、ベテランドライバーに走行してもらい、１０点満点でフィーリング評価を行った。試験結果を表２に示す。なお、ここで５．５⁺ のように数値の右肩に＋があるのは、５．５よりも若干良いことを示す。
【００３３】
【表２】

【００３４】
いずれの試験も実施例１の空気入りタイヤが最も優れた性能を示し、実施例２の空気入りタイヤも比較例に比べて性能向上がみられた。
【００３５】
【発明の効果】
請求項１記載の本発明に係る空気入りタイヤは、サイプを多数設けても小ブロックの倒れ込みを抑制できるため、氷雪路面において優れた走行性能を発揮することができる。
【００３６】
請求項２記載の本発明に係る空気入りタイヤは、サイプの凹凸によって隣接する小ブロック同士が噛み合い、より一層小ブロックの倒れ込みを抑制して氷雪路面における一層良好な走行性能を発揮できる。
【図面の簡単な説明】
【図１】本発明の第１実施形態に係る空気入りタイヤのトレッド平面図である。
【図２】本発明の第１実施形態に係るブロックの斜視図である。
【図３】本発明の第２実施形態に係るブロックの斜視図である。
【図４】本発明の第２実施形態に係るブロックの動作説明図である。
【図５】比較例に係るブロックの斜視図である。
【符号の説明】
１０ 空気入りタイヤ
１２ トレッド
１４ 主溝
１６ ラグ溝
１８ ブロック
２０、２２ 側面（タイヤ幅方向側面）
２４ サイプ
２６ 踏面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire that exhibits excellent running performance on icy and snowy road surfaces.
[0002]
[Prior art]
Conventionally, studless tires are provided with sipes on the tread surface block to improve running performance on icy and snowy road surfaces. That is, the edge length is substantially increased by the sipe provided on the block, and the grip force of the tire is secured by cutting a thin water film stretched on the snowy and snowy road surface (so-called edge effect). Therefore, it is desirable that the number of sipes provided in the block is larger.
[0003]
[Problems to be solved by the invention]
However, if the number of sipes in the block is increased too much, the rigidity of the block may be lowered and the steering stability may be lowered. Moreover, there is a possibility that the ground contact area may decrease due to the collapse of the block.
[0004]
In order to solve the above-described problems, an object of the present invention is to provide a pneumatic tire that can secure a sufficient ground contact area even if a large number of sipes are provided in a block.
[0005]
[Means for Solving the Problems]
The present invention according to claim 1 is a pneumatic tire having a plurality of sipe-in block-shaped land portions defined by a main groove extending in a tire circumferential direction provided on a tread surface and a lug groove intersecting the main groove. Te, the block-shaped land portion, the tread side by sipes extending in the tire width direction is divided into a plurality of small blocks, the small blocks at least one of the tire width direction sides base portion with respect to the direction perpendicular to the tread surface The side of the tire in the tire width direction of the small block adjacent to the small block is perpendicular to the tread or perpendicular to the tread. In this case, the vehicle is inclined at a predetermined angle in the second tire width direction opposite to the first tire width direction with the tread surface directed from the base portion.
[0006]
The operation of the present invention as set forth in claim 1 will be described.
When running with this pneumatic tire mounted on an actual vehicle, the small blocks divided by the sipes are deformed by the ground load. In other words, it comes into contact with adjacent small blocks due to the swelling in the tire circumferential direction. At the same time, since at least one side surface in the tire width direction is inclined at a predetermined angle in the first tire width direction, the small block is deformed as a whole in the first tire width direction. The adjacent small block is not deformed in the tire width direction because the side surface in the tire width direction is perpendicular to the tread surface or is inclined at a predetermined angle in the second tire width direction, or the second tire opposite to the first tire width direction. Deforms in the width direction. Therefore, adjacent small blocks are subjected to a force in the opposite direction in the tire width direction via the contact portion. Thereby, the falling of the small block is suppressed, the contact area on the tread surface is increased, and the steering stability is improved.
[0007]
According to a second aspect of the present invention, in the first aspect of the present invention, the sipe includes a first convex portion projecting in the first tire circumferential direction across the virtual center plane extending in the tire width direction and the first tire. It is the shape where the 2nd convex part convex in the 2nd tire circumferential direction opposite to the circumferential direction was formed alternately.
[0008]
The operation of the second aspect of the present invention will be described.
When running with this pneumatic tire mounted on an actual vehicle, the small blocks divided by the sipes are deformed by the ground load. In other words, it comes into contact with adjacent small blocks due to the swelling in the tire circumferential direction. At the same time, since at least one side surface in the tire width direction is inclined at a predetermined angle in the first tire width direction, the small block is deformed as a whole in the first tire width direction. The adjacent small block is not deformed in the tire width direction because the side surface in the tire width direction is perpendicular to the tread surface or is inclined at a predetermined angle in the second tire width direction, or the second tire opposite to the first tire width direction. Deforms in the width direction. As a result, the tire circumferential side surfaces of the small blocks adjacent to each other across the sipe move in opposite directions in the tire width direction, and the zigzag shape is formed between the first convex portion and the second convex portion of the sipe. The formed tire circumferential side surfaces mesh with each other. Thereby, the falling of the small block is suppressed, the contact area of the tread surface is increased, and the steering stability is further improved.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
A pneumatic tire according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
[0010]
As shown in FIG. 1, the tread 12 of the pneumatic tire 10 of the present embodiment includes a main groove 14 extending in the tire circumferential direction (arrow A direction, hereinafter referred to as A direction) and a tire width direction (arrow B direction). A plurality of blocks 18 defined by lug grooves 16 extending along the direction B) are formed.
[0011]
As shown in FIG. 2, the block 18 is provided with a plurality of sipes 24 whose ends are open on both side surfaces 20 and 22 in the B direction. By this sipe 24, the tread surface 26 side of the block 18 is divided into small blocks 18a to 18f.
[0012]
The small block 18a is formed to be inclined in the B1 direction from the base portion toward the tread surface 26. That is, the B1 and B2 side surfaces 20a and 22a are formed to be inclined in the B1 direction by an angle θ1.
[0013]
The adjacent small blocks 18b are formed to be inclined in the B2 direction from the base portion toward the tread surface 26. That is, the B1 and B2 direction side surfaces 20b and 22b are formed to be inclined in the B2 direction by an angle θ2.
[0014]
As described above, the small blocks 18a to 18f adjacent in the A direction are alternately inclined in the B1 and B2 directions.
[0015]
In the sipe 24, first convex portions 24a that are convex in the A1 direction with respect to the virtual center plane V and second convex portions 24b that are convex in the A2 direction opposite to the A1 direction are alternately formed in the B direction. That is, the sipe 24 is formed in a zigzag shape.
[0016]
The dimensions of the block 18 of the present embodiment are as follows. The length L × width W × height H of the block 18 is 30 mm × 20 mm × 10 mm, and the inclination angles θ1 and θ2 of the B-direction side surfaces 20 and 22 of the small blocks 18a to 18f are both 15 °. The sipe width S is 0.4 mm, and the length P in the A direction of the small block is 4.7 mm.
[0017]
The sipe shape of the present embodiment is a zigzag shape, but any shape may be used as long as irregularities are alternately formed such as a waveform.
[0018]
Further, the inclination angles θ1 and θ2 are preferably 0 ° <θ1 and θ2 ≦ 30 °. This is because if it exceeds 30 °, block chipping or the like may occur when the tire is removed from the mold during molding.
[0019]
When the pneumatic tire 10 formed in this way is mounted on an actual vehicle, the following effects are obtained.
[0020]
That is, the ground load F acts from the tread 26 of the block 18. Thereby, since the small blocks 18a, 18c, and 18e are formed to be inclined in the B1 direction from the base portion toward the tread surface 26, they are deformed in the B1 direction.
[0021]
On the other hand, the small blocks 18b, 18d, and 18f are formed so as to be inclined in the B2 direction from the base portion toward the tread surface 26, and thus are deformed in the B2 direction opposite to the B1 direction by the ground load F.
[0022]
As a result, the concave and convex surfaces of the small blocks 18a to 18f formed in a zigzag shape by the sipe 24 are strongly meshed with each other. Therefore, even if a force in the A direction acts on each of the small blocks 18a to 18f as the tire rotates, the small blocks 18a to 18f fall down because the adjacent small blocks are strongly meshed with each other due to the deformation in the B direction. It is suppressed. As described above, the pneumatic tire 10 increases the edge effect by forming a large number of sipes 24 in the block 18, and suppresses the collapse of the A direction due to the deformation of the small blocks 18a to 18f in the B direction. Sufficient ground contact area can be secured and good steering stability on icy and snowy road surfaces.
[0023]
[Second Embodiment]
Next, a pneumatic tire according to a second embodiment of the present invention will be described with reference to FIGS. 3 and 4. Since the difference from the first embodiment is only the sipe shape of the block, only the sipe will be described. In addition, the same referential mark is attached | subjected to the component similar to 1st Embodiment, and the detailed description is abbreviate | omitted.
[0024]
As shown in FIG. 3, the sipe 40 formed in the block 18 has a shape that is straight in the B direction.
[0025]
The dimension of the block 18 of this embodiment is the same as that of the first embodiment. That is, the length L × width W × height H of the block 18 is 30 mm × 20 mm × 10 mm, and the inclination angles θ1 and θ2 of the B-direction side surfaces 20 and 22 of the small blocks 18a to 18f are both 15 °. The sipe width S is 0.4 mm, and the length P in the A direction of the small block is 4.7 mm.
[0026]
When such a block 18 is mounted on a real vehicle and travels with a pneumatic tire formed on the surface of the tread 12, the following effects are obtained.
[0027]
When the ground load F acts on the block 18, the small blocks 18 a to 18 f are compressed in the C direction. As a result, the small blocks 18a to 18f expand in the A direction, and adjacent small blocks come into contact with each other. Adjacent small blocks are deformed in the opposite direction in the B direction as in the first embodiment. For example, in FIG. 4, the small block 18a is deformed in the B1 direction, and the small block 18b is deformed in the B2 direction (see the thick arrow). Therefore, opposite forces in the B1 and B2 directions act on the adjacent small blocks via the contact portion 42 (see the thin line arrows). As a result, the fall of the small blocks 18a to 18f caused by the rotation of the tire in the A direction can be suppressed.
[0028]
In the first and second embodiments, θ1 and θ2 are the same angle, but they may be different. Further, although both the side surface 20 and the side surface 22 are inclined, only one of them may be used. If one side surface of at least one small block is inclined, and the side surface of the adjacent small block is vertical (parallel to the C direction) or inclined in the opposite direction, the operation of the present invention (adjacent small block) The blocks are deformed relatively in the opposite direction in the B direction).
[0029]
[Test example]
In order to demonstrate such an action of the present invention, the braking performance on ice and the steering stability were tested. Examples 1 and 2 are the pneumatic tires of the first and second embodiments, respectively, and the comparative example has the angles θ1 and θ2 = 0 in the second embodiment. That is, in the pneumatic tire of the comparative example, the side surfaces in the B direction of the small blocks 18a to 18f are formed in parallel to the C direction as shown in FIG.
[0030]
In the on-ice brake performance test, a pneumatic tire was mounted on an actual vehicle, the brake was suddenly applied while traveling on an icy road surface at a speed of 20 km / h, the braking distance was measured, and the reciprocal number was defined as the on-ice brake performance. The index evaluation was made with the braking performance on ice of the comparative example as 100. The larger the index, the better the braking performance. The test results are shown in Table 1.
[0031]
[Table 1]

[0032]
In the steering stability test, each pneumatic tire was attached to an actual vehicle, and a veteran driver ran the vehicle to evaluate the feeling with a maximum of 10 points. The test results are shown in Table 2. Here, a ⁺ on the right shoulder of the numerical value such as 5.5+ indicates that it is slightly better than 5.5.
[0033]
[Table 2]

[0034]
In any of the tests, the pneumatic tire of Example 1 showed the most excellent performance, and the performance improvement of the pneumatic tire of Example 2 was also seen compared to the comparative example.
[0035]
【The invention's effect】
Since the pneumatic tire according to the first aspect of the present invention can suppress the falling of the small blocks even if a large number of sipes are provided, it can exhibit excellent running performance on icy and snowy road surfaces.
[0036]
In the pneumatic tire according to the second aspect of the present invention, adjacent small blocks are engaged with each other by the unevenness of the sipe, and the falling of the small blocks can be further suppressed, and better running performance on an icy and snowy road surface can be exhibited.
[Brief description of the drawings]
FIG. 1 is a plan view of a tread of a pneumatic tire according to a first embodiment of the present invention.
FIG. 2 is a perspective view of a block according to the first embodiment of the present invention.
FIG. 3 is a perspective view of a block according to a second embodiment of the present invention.
FIG. 4 is an operation explanatory diagram of a block according to a second embodiment of the present invention.
FIG. 5 is a perspective view of a block according to a comparative example.
[Explanation of symbols]
10 Pneumatic tire 12 Tread 14 Main groove 16 Lug groove 18 Blocks 20 and 22 Side surface (side surface in the tire width direction)
24 Sipe 26 Tread

Claims (2)

A pneumatic tire having a plurality of sipe-containing block-like land portions defined by main grooves extending in the tire circumferential direction provided on the tread surface and lug grooves intersecting the main grooves,
Block-shaped land portion, the tread from the base portion with respect to the tread side is divided into a plurality of small blocks, the small blocks at least one of the tire width direction sides perpendicular to the tread surface by sipes extending in the tire width direction And the side surface in the tire width direction of the small block adjacent to the small block is perpendicular to the tread surface or a base with respect to the direction perpendicular to the tread surface. A pneumatic tire characterized by being inclined at a predetermined angle in a second tire width direction opposite to the first tire width direction with a tread surface directed from a portion.   The sipe has a first convex portion convex in the first tire circumferential direction across a virtual center plane extending in the tire width direction and a second convex portion convex in the second tire circumferential direction opposite to the first tire circumferential direction. The pneumatic tire according to claim 1, wherein the pneumatic tire has an alternately formed shape.

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