JP2003320815A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire having excellent ice performance and uneven wear resistance performance because edge effect and water removing effect can be sufficiently secured by suppressing falling-down of a block. <P>SOLUTION: This pneumatic tire is provided with a tread pattern having a plurality of blocks 1 in which a plurality of sipes 10 are juxtaposed in a tire peripheral direction PD or in a direction inclined from the tire peripheral direction PD. The plurality of sipes 10 are one-side closed and/or both-sides closed, are constituted of wide sections WS and narrow sections NS which are different in groove width, and have alternately arranging regions AR in which the wide sections WS and the narrow sections NS are alternately arranged in a juxtaposing direction. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pneumatic tire having a tread pattern having a plurality of blocks in which a plurality of sipes are juxtaposed in a tire circumferential direction or a direction inclined from the tire circumferential direction, and particularly useful as a studless tire. Is.

[0002]

2. Description of the Related Art Conventionally, it has been known that a plurality of sipes are arranged in each part (center part, mediate part, shoulder part) of a tire pattern for the purpose of improving the ice performance of a studless tire. As the shape of such a sipe, a sipe having a straight or corrugated cross-sectional shape is generally used. The number of sipes tends to increase in recent years because the edge effect, the water removing effect, and the adhesion effect are improved by forming such sipes in the block.

However, when the number of sipes is increased and the sipes density is increased, the number of edges increases, but the rigidity of the entire block decreases and the sipes fall excessively, which conversely reduces the edge effect. There is a problem that the ground contact area becomes small and the ice performance also deteriorates. Further, if the groove width of the sipe is widened, the water removing effect can be easily secured, but in this case too, the similar adverse effect is likely to occur due to excessive collapse of the sipe.

On the other hand, instead of the conventional sipes having the same groove width,
Pneumatic tires having sipes with different groove widths have also been proposed. For example, Japanese Unexamined Patent Publication (Kokai) No. 2-197402 also proposes a pneumatic tire in which a narrow portion and a wide portion are alternately provided for one sipe.

[0005]

However, in this tire, when the sipes are juxtaposed with each other, the wide part is continuously established in the juxtaposed direction in about 1/2, so that in the area where the wide part is continuous. Sipes are likely to fall excessively. Therefore, the edge effect may be reduced, the ground contact area may be reduced, and the ice performance may be reduced. On the contrary, the water removing effect tends to be insufficient in the region where the narrow portions are continuous.

[0006] Therefore, an object of the present invention is to provide a pneumatic tire having good ice performance and uneven wear resistance, since the edge effect and the water removing effect can be sufficiently ensured by suppressing the collapse of the block.

[0007]

The above object can be achieved by the present invention as described below. That is, the pneumatic tire of the present invention is a pneumatic tire having a tread pattern having a plurality of blocks in which a plurality of sipes are juxtaposed in a tire circumferential direction or a direction inclined from the tire circumferential direction, wherein the plurality of sipes are on one side. It is closed or closed on both sides , and is configured by a wide portion and a narrow portion having different groove widths, and has an alternating arrangement region in which the wide portion and the narrow portion are alternately arranged in the juxtaposed direction. To do. Here, the one-side closed refers to a sipe whose one end is open to the side wall of the block, and the both-side closed is a sipe whose both ends are not open to the side wall of the block.

In the above description, one sided closed sipe having approximately half of one sipe as the wide portion and the remaining portion as the narrow portion is sequentially arranged in the opposite direction, and the alternating arrangement region is provided in the arranged region. Is preferably 80% or more.

Alternatively, it is preferable that the one-side closed sipe mainly formed in the wide portion and the one-side closed sipe mainly formed in the narrow portion are alternately arranged in reverse order.

Further, the groove width of the wide portion is 0.3 to 0.8.
It is preferable that the groove width of the narrow portion is 0.2 to 0.6 mm. Further, it is preferable that the wide portion and the narrow portion of the alternating arrangement region have a wavy or zigzag cross-sectional shape.

[Operation and Effect] According to the present invention, since the wide portion and the narrow portion have the alternating arrangement region in which the wide portion and the narrow portion are alternately arranged in the juxtaposing direction, when a longitudinal force having a component in the juxtaposing direction occurs. Moreover, even if the narrow portion is closed, it is difficult to close the wide portion, so that it is easy to secure the edge effect and the water removing effect. In addition, compared with the case where the whole is composed of wide parts, the block can be prevented from collapsing due to the interposition of narrow parts, and furthermore, the rigidity of the whole block can be easily maintained because it is closed on one side or both sides. The uneven wear resistance is also improved.
As a result, the collapse of the block can be suppressed and the edge effect and the water removing effect can be sufficiently ensured, so that it is possible to provide a pneumatic tire having good ice performance and uneven wear resistance.

One side closed sipe having approximately half of one sipe as the wide portion and the rest as the narrow portion is sequentially arranged in the opposite direction, and 80% of the alternating arrangement areas are provided in the arranged areas. In the case of occupying the above, since the alternating arrangement region can be made sufficiently large, the ice performance and the uneven wear resistance can be more surely improved.

When the one-sided closed sipes mainly formed in the wide portion and the one-sided closed sipes mainly formed in the narrow portion are alternately arranged side by side in the opposite direction, the alternating arrangement region is sufficient. Since the area can be increased, the ice performance and the uneven wear resistance can be improved more reliably.

When the groove width of the wide portion is 0.3 to 0.8 mm and the groove width of the narrow portion is 0.2 to 0.6 mm, the function of the sipe as described above can be obtained more reliably. be able to.

When the wide section and the narrow section of the alternating arrangement region have a wavy or zigzag cross-sectional shape, an edge effect and a water removing effect are secured even in an external force direction other than the sipe juxtaposition direction. Easier to do.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the pneumatic tire of the present invention includes a tread pattern T having a plurality of blocks 1 in which a plurality of sipes 10 are arranged in parallel in the tire circumferential direction PD or in a direction inclined from the tire circumferential direction PD. In the present embodiment, an example is shown in which the sipes 10 are arranged in parallel in the tire circumferential direction PD with respect to the blocks 1 divided by the circumferential groove 2 and the lateral groove 3, and five rows of blocks 1 are arranged in the tire width direction. .

In the present invention, the plurality of sipes 10 are closed on one side and / or closed on both sides.
Shows an example in which only one side closed sipes 10a to 10c are provided. When installing closed sipes on both sides,
All or part of the one-side closed sipes 10a to 10c may be double-sided closed sipes.

In the present invention, the plurality of sipes 10 are composed of the wide portion WS and the narrow portion NS having different groove widths.
The width of the wide portion WS is wider than that of S. The groove width of the wide portion WS is preferably 0.3 to 0.8 mm, and the groove width of the narrow portion NS is preferably 0.2 to 0.6 mm, for the reason described above.

Further, in the present invention, the wide portion WS and the narrow portion N
S and S have an alternating arrangement area AR in which they are alternately arranged in the arranging direction (that is, the tire circumferential direction PD). 2 to 3,
An example is shown in which the entire alternating array region AR is composed of a wide portion WS and a narrow portion NS having a wavy or zigzag cross section.

In the embodiment shown in FIG. 2, one-side closed sipes 10a each having a wide portion WS and a remaining portion NS having a wide portion WS of approximately one half of the sipes are arranged side by side in reverse order to form an alternating arrangement area AR. Is forming. In this case, it is preferable that the alternately arranged regions AR occupy 80% or more in the juxtaposed regions. This ratio is 100 × (Y2 + Y2) / Y
It can be calculated by 4 (%).

In this embodiment, the closed side of the one-side closed sipe 10a is the wide portion WS, but the closed side may be the narrow portion NS. Also, in the area of width Y3,
Although the wide portion WS is arranged, the narrow portion NS may be arranged.

In the embodiment shown in FIG. 3, the one-side closed sipe 10b mainly formed by the wide portion WS and the narrow portion N are formed.
The one-side closed sipes 10c mainly formed of S are alternately arranged side by side in the opposite direction to form the alternating arrangement area AR.

In this embodiment, the area where the sipes 10 are arranged in parallel with the alternating arrangement area AR are the same, but the sipes 10 are arranged in parallel by reversing a part of the wide portion WS or the narrow portion NS. It is possible that the area to be formed and the alternating array area AR do not completely match. Further, the central portions of the wide width portion WS and the narrow width portion NS may be reversed in the same length range so that the area becomes the alternating arrangement area AR.

In any of the embodiments shown in FIGS. 2 to 3, the ratio of the alternating array area AR in the block 1 is sufficient to prevent the blocks from collapsing and sufficiently secure the edge effect and the water removing effect. , 60% or more is preferable, and 70 to
90% is more preferable. This ratio is 100 x Y4 / Y
It can be calculated by 1 (%).

The cross-sectional shape of the alternating array region AR is wavy or zigzag, but is not limited to a sine wave.
Any shape may be used, such as a wavy line obtained by alternately combining straight lines and curved lines, or a shape close to a rectangular wave. In addition, the sipe 10 may partially have a straight line portion whose cross-sectional shape is a straight line. By making the end portion linear, it is possible to prevent the end portion from opening at an acute angle with respect to the groove, and the acute angle portion from being easily damaged.

The period of the unevenness of the cross-sectional shape of the alternating array region AR (for example, the distance between the convex-convex tops) is preferably 1.5 to 5 mm in order to suitably exhibit the characteristics of so-called corrugated sipe, and the amplitude ( The sum of the heights of the tops on both sides) is preferably 1.5 to 5 mm.

The groove depth of the sipe 10 is preferably 30 to 80% of the main groove depth. The sipe 10 is generally formed to be perpendicular to the block surface, but the sipe may be slightly inclined (for example, 15 ° or less) with respect to the normal line of the block surface.

The pneumatic tire of the present invention is the same as a normal pneumatic tire except that it has the tread pattern T as described above, and any conventionally known materials, shapes, structures, manufacturing methods, etc. are adopted in the present invention. it can.

The pneumatic tire of the present invention is particularly useful as a studless tire because it has the above-mentioned effects and is excellent in ice performance.

[Other Embodiments] Other embodiments of the present invention will be described below.

(1) In the above-described embodiment, an example in which the entire alternating array region is composed of wide portions and narrow portions having a wavy or zigzag cross section is shown. One or both of the narrow portions may be linear. vice versa,
The entire sipe may be formed in a wavy or zigzag cross section.

(2) In the above-described embodiment, an example of the block pattern as shown in FIG. 1 is shown, but the block pattern is not limited to this shape, and it may be a parallelogram, a V-shape, a pentagon, or a curved tone. It can be a block. In addition, a block having a groove up to the vicinity of the center or the vicinity of the edge or a part of the land may be continuous in the circumferential direction.

(3) In the above-described embodiment, as shown in FIG. 1, an example in which a plurality of sipes 10 are arranged in the tire circumferential direction PD has been shown. However, they are arranged in a direction inclined from the tire circumferential direction PD. You may have. However, in that case, the tire circumferential direction PD
The angle formed by and the parallel direction is preferably 0 to 45 °.

(4) In the above-mentioned embodiment, as shown in FIG. 1, an example in which a plurality of sipes 10 are arranged in parallel in the tire circumferential direction PD is shown. However, each sipes has a constant angle. It may be provided side by side. In that case, the angle formed by the reference line of each sipe is preferably 0 to 20 °.

[0035]

EXAMPLES Examples and the like specifically showing the constitution and effects of the present invention will be described below. In addition, each performance evaluation of the tire was performed as follows.

(1) Ice braking performance tires are actually used (FF sedan of domestic 1800cc class)
The vehicle was mounted on a vehicle and the vehicle was run on a frozen road surface under a load condition of one passenger, and braking force was applied at a speed of 40 km / h to fully lock the vehicle. In addition, the evaluation is shown by the index display when the conventional product (Comparative Example 1) is 100,
The larger the value, the better the result.

(2) Step wear The step wear amount (step difference between sipes due to wear) when running on a dry paved road for 8000 km was measured and evaluated by an index. In addition, the evaluation is 100 for the conventional product (Comparative Example 1).
Is shown in an index display, and the larger the value, the better the result.

Example 1 In a tread pattern as shown in FIG. 1, sipes having the shape shown in FIG.
A 65R14 radial tire was manufactured. Table 1 shows the results of the above performance evaluations using this tire.
Sipe depth 7 mm, wide part groove width 0.6 mm, narrow part groove width 0.3 mm, 100 × (Y2 + Y2) / Y4
90%, 100 × Y4 / Y1 70%, amplitude 1.5m
m and the period was 4.0 mm.

Example 2 In a tread pattern as shown in FIG. 1, sipes having the shape shown in FIG.
A 65R14 radial tire was manufactured. Table 1 shows the results of the above performance evaluations using this tire.
Sipe depth is 7 mm, wide part groove width is 0.6 mm, narrow part groove width is 0.3 mm, 100 × Y4 / Y1 is 70%,
The amplitude was 1.5 mm and the period was 4.0 mm.

Comparative Example 1 (Conventional Product) In the tread pattern as shown in FIG.
A sipe having the shape of (a) was formed in the following size to manufacture a radial tire of size 185 / 65R14. Table 1 shows the results of the above performance evaluations using this tire. The sipe depth was 7 mm, the groove width was 0.4 mm, the amplitude was 1.5 mm, and the cycle was 4.0 mm.

Comparative Examples 2 to 4 In the tread pattern as shown in FIG.
The sipes in the shapes of (b) to (d) were formed in the following sizes to manufacture a radial tire of size 185 / 65R14. Table 1 shows the results of the above performance evaluations using this tire. Sipe depth 7 mm, wide groove width 0.6 mm, narrow groove width 0.3 mm, amplitude 1.5
mm, and the cycle was 4.0 mm.

[0042]

[Table 1] As shown in the results of Table 1, the ice braking performance and the uneven wear resistance performance of the example are better than those of the conventional products. On the other hand, in Comparative Example 2 in which the wide portion is mainly provided on both sides of the open sipe, the effect of suppressing the collapse of the block is insufficient, step wear is likely to occur, and the wide portion and the narrow portion are alternately opened on both sides. In Comparative Example 3 provided on the sipe, the effect of suppressing the collapse of the block is not sufficient, and the effect of improving ice braking performance and step wear is small. Further, in Comparative Example 4 in which the wide portions are adjacent to each other and the narrow portions are adjacent to each other, the effect of suppressing the collapse of the block is not sufficient, the effect of improving the ice braking performance is small, and the step wear is likely to occur.

[Brief description of drawings]

FIG. 1 is a plan view showing a tread surface of an example of a pneumatic tire of the present invention.

FIG. 2 is an enlarged view of an essential part showing an example of a block according to the present invention.

FIG. 3 is an enlarged view of an essential part showing another example of the block in the present invention.

FIG. 4 is an enlarged view of a main part showing an example of a block adopted in a comparative example.

[Explanation of symbols]

1 block 10 sipes 10a One side closed sipe (about half wide part) 10b Closed sipe on one side (mainly wide part) 10c Closed sipe on one side (mainly narrow part) T tread pattern WS Wide part NS narrow part AR alternating array region PD tire circumferential direction

Claims (5)

[Claims] 1. A pneumatic tire provided with a tread pattern having a plurality of blocks in which a plurality of sipes are juxtaposed in a tire circumferential direction or a direction inclined from the tire circumferential direction, wherein the plurality of sipes are closed on one side and / or on both sides. It is closed and is composed of a wide portion and a narrow portion with different groove widths, and has an alternating arrangement region in which the wide portion and the narrow portion are alternately arranged in the juxtaposed direction. tire. 2. One sided closed sipe, in which approximately half of one sipe is the wide portion and the remaining portion is the narrow portion, is arranged side by side in the opposite direction, and the alternating arrangement area is formed in the arranged area. The pneumatic tire according to claim 1, wherein the pneumatic tire occupies 80% or more. 3. The one-side closed sipe mainly formed in the wide portion and the one-side closed sipe mainly formed in the narrow portion are alternately arranged in parallel in opposite directions. Pneumatic tires. 4. The groove width of the wide portion is 0.3 to 0.8 mm.
4. The pneumatic tire according to claim 1, wherein the groove width of the narrow portion is 0.2 to 0.6 mm. 5. The wide portion and the narrow portion of the alternating arrangement region are
The pneumatic tire according to claim 1, wherein the cross-sectional shape is wavy or zigzag.