JPH0616016A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To provide a pneumatic tire which is uniformalized together with improved edge effect and drain performance without reducing block rigidity of a tread surface. CONSTITUTION:A tread 1 is provided with a plurality of main grooves 5 and a lot of sub-grooves 6 communicating with the main grooves, on its surface and has a plurality of block lands 9 partitioned by these grooves. These block land parts are provided with vein-shaped combined nothces 12 having trunk notches 10 which extend from the main grooves or the sub-grooves respectively and allow their tips to stay inside the substances of the land parts and branch notches 11 which extend in different directions from the trunk notches to both sides and allow their tips to stay inside of the substances of the lands parts respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire which can be used in all weathers and can be used especially when traveling on a road surface having snow or ice.

[0002]

2. Description of the Related Art Since pneumatic tires for automobiles are required to have various performances such as braking performance and traction performance, various tread patterns are provided according to the required performances. In particular, all-weather pneumatic tires should have a tread pattern that allows the tread surface to properly grasp the road surface and to exert sufficient edge effect and drainage performance even when the road surface is covered with snow or ice. Is required. In order to have the former performance, rubber that shows soft properties even in low temperature use environment is used for the tread material, and in the latter case, in terms of the edge effect depending on the tread pattern, multiple sipes are used on the tread surface. It is effective to provide a plurality of sipes in terms of drainage so that they communicate with the groove that defines the land portion that determines the tread pattern. The conventional sipe shape is generally linear in one direction or zigzag.

[0003]

However, in order to satisfy both the edge effect and the drainage property described above, it is necessary to provide a plurality of sipes communicating with the groove that defines the land portion that determines the tread pattern. As a result, the land portion of the tread surface is further subdivided, which causes a problem that the rigidity of the land portion of the tread is lowered.

[0004] Pneumatic tires that have been made uniform without lowering the rigidity of the land portion of the tread and have improved edge effects and drainage properties, in particular, running on bad weather road surfaces such as snow and icy road surfaces. It is an object of the present invention to provide an all-weather pneumatic tire that can be used also in.

[0005]

SUMMARY OF THE INVENTION The present invention provides a tire having a tread including a block-shaped land portion divided by a plurality of main grooves and a plurality of sub-grooves communicating with the main groove. In the land part, a trunk cut extending from the main groove or the sub-groove and having a tip staying in the land parenchyma, and a branch notch extending in different directions from the trunk cutting to both sides thereof, and each tip staying in the land parenchyma A pneumatic tire having a composite notch including

The tire of the present invention will now be described with reference to the drawings. A feature of the tire of the present invention is that the tread pattern is improved, and since the internal structure of the tire does not need to be modified for a general radial tire, the present invention can be followed.

1 to 3 show a developed tread, which is typical of the tire of the present invention. In the tread pattern shown in FIG. 1, the main grooves 5 are inclined and converged from both ends of the tread 1 toward the center region of the tread, and are arranged in multiple rows at intervals along the outer circumference of the tire. The main grooves 5 are staggered left and right, and the tips of the main grooves located in the tread central region intersect in a T shape laterally of the main groove extending from the other tread end, and the tip portions of the main grooves located in the tread central region. The zigzag groove is formed along the circumference of the tread.

The sub-grooves 6 intersect with the main groove 5 and make a pair on both sides thereof, and their tips remain in the land substantially.
When the side of the main groove is on the extension of one end of the sub groove 6 that does not intersect with the main groove 5, a linear single cut 7 is formed in the land portion between the one end of the sub groove 6 and the side of the main groove 5. If the tread end is provided on the extension of the tip of the sub groove 6, the branch cut 8 is provided in the land portion between the tip of the sub groove 6 and the tread end.

For convenience, the zigzag groove located in the central area of the tread is symmetrical and the tread is divided into two areas. In each area, the land portions located between the adjacent main grooves are the main groove 5 and the sub groove. Groove 6 and single notch 7
And / or branch notch 8 divides it into five block-like land portions 9.

In the substantially divided block-shaped land portion 9, a composite cut 12 including a main cut 10 and a branch cut 11 is provided.

The main notch 10 has one end intersecting the main groove 5 or the sub groove 6 and the other end remaining in the land substantially. In FIG. 1, the main notch is shown in a straight line shape, but it may be in a crank shape or a curved shape.

The branch notch 11 intersects the trunk notch 10 at one end thereof and branches off on both sides thereof, while the other end remains in the land substance. The branch cuts 11 are preferably a pair, and the arrangement angle at this time is preferably 90 ° or more, and the number of the pairs is preferably about 1 to 4 pairs per one main trunk cut 10. This is because if the arrangement angle is less than 90 °, the difference between the angles formed by the trunk cut 10 and the pair of branch cuts 11 is small, and the intended edge effect is diminished.

In each block-shaped land portion 9, in order to keep the rigidity of the land portion of the tread uniform, the respective main notch portions 10 are arranged so that the composite notch portions 12 adjacent to each other are
It is preferable that they are parallel to each other and at the same time parallel to any of the grooves forming the block-shaped land portions 9,
It is also preferable that the adjacent composite cuts 12 extend in an alternating manner. In the block-shaped land portion 9 in the central region, the tread of FIG. 1 is arranged so that the trunk notch 10 is not parallel to any of the grooves forming the block-shaped land portion, but is parallel to the other land portions. 2 and 3, the trunk notch 10 is arranged in all the block-shaped land portions 9 in parallel with at least one of the above grooves.

The cutting depth of the composite notch 12 is
The depth of the main groove 5 at which the main notch 10 intersects is equal to or shallower than that, and the notch width is such that when the tread surface of the tire touches the ground, the notch width is 0.5 to 1.
It is preferably about 5 mm.

The cuts that make up the composite cut 12 are:
It consists of three directional components, i.e., bidirectional components of the branch notch 11 paired with the unidirectional component of the main notch 10. It is preferable that one of the three directional components is provided so as to form an angle of 0 to 15 ° with respect to the plane including the rotation axis.

The reason is that the edge effect of this directional component is responsible for the braking and traction performance, and the remaining 2
This is because the edge effects of the three different direction components are used to resist the lateral force in particular. Compound notch 1
2 is longer than the conventional single sipe such as a straight line, and because the main groove or the sub groove and one end of the cut are in communication with each other, the moisture that has become a water film on the ice The drainage performance is also high. In addition, this compound notch 12
Since the one end of the cut does not intersect with the other groove, the rigidity of the land portion of the tread can be secured.

In the tread pattern of the invention tire shown in FIG. 2, two zigzag-shaped main grooves 5 slightly bent in a crank shape are arranged along the circumference of the tread. The main groove 5 divides the tread 2 into three substantially equal parts, and is divided into one region 15 located between the two main grooves and two regions 14 and 16 located between the main groove and the tread edge.

The first sub-grooves 13 are substantially parallel to the plane including the rotation axis, are arranged in multiple rows along the outer circumference, communicate with the three regions 14 to 16, and are connected to the main groove 5. It has a crank-shaped bent portion at the intersection and the central portion of each of the regions 14 to 16,
In those portions, the first sub groove 13 has a step shape. On both sides of the bent portion of the first sub-groove 13, a pair is formed with respect to a plane including the tread circumference and branched at a slight angle,
A second auxiliary groove 17 is arranged, one end of which remains in the land substantially.

The above three regions 14 to 16 have two first sub-grooves 13 which are adjacent to the main groove 5 at intervals along the outer circumference of the tread.
Is further divided by
By disposing the single cut 7 between the second sub grooves facing each other, the two blocks 18 and 19 are divided. The single notch 7 has a notch width such that it closes when the tread surface of the tire enters the contact area during traveling, so that the rigidity of the land portion of the tread can be maintained.

In each of the two blocks 18 and 19 divided by the single cut 7, the arrangement of the composite cut 12 including the main cut 10 and the branch cut 11 is such that the main cut 10 is the first sub groove 13 respectively. Are substantially parallel to each other, and the composite notches 12 are staggered in each of the blocks 18 and 19. The other structure is the same as the tread of FIG.

The tread pattern of the invention tire shown in FIG. 3 has two main grooves 5 arranged in a zigzag shape by connecting main groove constituent components 22 and 23 having two directions along the circumference of the tread. There is. These main grooves 5 are similar to the inventive tire of FIG. 2 and divide the tread 3 into three substantially equal parts, and the tread 3 is divided into two regions, one region 15 located between the two main grooves, the main groove 5 and the tread. It is divided into two regions 14 and 16 located between the ends.

From both ends of one main groove constituent component 22, first sub-grooves 13 each having a relatively narrow width extend on the extension thereof, and from the tips of the two extending first sub-grooves 13, respectively. A relatively wide second sub-groove 17 is provided in the opposite direction and parallel to the groove of the other main groove constituent 23. The two regions 14 and 16 of the tread extend from the tip of the second sub groove 17 on the tread end side in parallel to the first sub groove 13 and toward the tread end, and have the groove width of A third sub groove 20, which is the same as one sub groove, is provided.

In addition, the two second sub-grooves 17 that are adjacent to each other along the circumference of the tread at regular intervals compare the end of one of the second sub-grooves 17 with the opposite end of the other second sub-groove 17. They are connected by a fourth auxiliary groove 21 having a narrow target width. In the whole land portion of the tread 3, the fourth sub groove 21 is used as a part of the groove that constitutes the tread 3. In each of the land portions, the composite cutouts 12 are arranged so that the main cutouts 10 are parallel to the second auxiliary grooves 17 and are staggered. The other structure is the same as the tread of FIG.

[0024]

In this pneumatic tire, in the tread pattern having the main groove and the sub-groove as described above, a plurality of compound notches are alternately arranged on each land portion of the tread, and only one of the notched ends is arranged. By communicating with the groove,
The rigidity of the land portion of the tread can be maintained uniformly without lowering, and the edge effect and the drainage property can be improved together.

[0025]

EXAMPLES A comparative test between the tire of the present invention and a conventional tire will be described below. ◎ Test tire ・ Invention tire 1 This tire has the tread pattern shown in Fig. 1, the size is PSR185 / 70R13, and the tread width is 1.
It is 50 mm. The main groove 5 has a groove width of 5 mm in the tread central region, 9 mm near the tread edge, and 7 mm in the middle.
mm. The width of the sub groove 6 was 5 mm. Further, there are two types of arrangement of the composite cutouts 12 in each block-shaped land portion 9, that is, blocks A and B. Block A
In the case of, the arrangement between the adjacent composite notches 12 is
The main cuts 10, which are its constituents, are parallel and staggered, and one crossing angle with the plane including the rotation axis is set to 10 °. The angle formed by the pair of branch cuts 11 was 130 °. 10 main cuts
One end of the branch groove 11 communicates with the main groove 5 or the sub groove 6, and one end of the branch cut 11 communicates with the trunk cut 10. In the case of the block B, the disposition of the composite notches 12 is the same as that of the block A except that the main notch 10 as a constituent thereof has a single intersecting angle of 10 ° with a plane orthogonal to the rotation axis. Is.

Invention Tire 2 This tire has the tread pattern shown in FIG. The groove width of the main groove 5 is 6 to 8 mm, the groove width of the first auxiliary groove 13 is 7 mm, and the second auxiliary groove 17 extends at an inclination of 20 ° with respect to the circumferential direction, and the groove width is 7 mm. . Each block 18,
19 has two compound notches 12 and is arranged so that the main notches 10 of its constituent components are staggered and parallel to each other and to the plane including the rotation axis. Except for the above conditions, the tire 1 has the same structure as the invention tire 1.

Inventive Tire 3 This tire has the tread pattern shown in FIG. The main groove 5 has a main groove constituent component 22 having two directions,
23, the groove width of the constituent component 22 was 7.5 mm, the groove width of the constituent component 23 was 7.5 mm, and the intersecting angle of these main groove constituent components 22 and 23 was 110 °. First sub groove 1
3 and the third auxiliary groove 20 are parallel to the main groove constituent component 22,
The groove width was 4 mm. The second auxiliary groove 17 is parallel to the main groove constituent component 23 and has a groove width of 6 mm. The fourth sub groove 21 is parallel to the first sub groove 13 and has a groove width of 2 mm. Each land portion has two compound notches 12, and the main constituent notches 10 of its constituent components are arranged so that they are staggered and parallel to each other, and one intersecting angle with the plane including the rotation axis is 65 °. Except for the above conditions, the tire 1 has the same structure as the invention tire 1.

Conventional tire This tire has the tread having the block pattern shown in FIG. 4, and the other structures are the same as those of the invention tire 1.

◎ Test method Using each of the above tires under an internal pressure of 1.8 kgf / cm 2 and under the same load as two passengers riding in an actual vehicle, a snow feeling test and an ice feeling test were conducted. It was The snow feeling test is an overall feeling evaluation of handling, starting, acceleration, and braking on a road surface in a compressed snow condition. The feeling test on ice is an evaluation of the feeling of circular turning, braking, and startability on the ice board. Table 1 shows the results of these tests. Table 1
Numerical values are shown as an index ratio with the performance of the conventional tire as 100, and the larger the numerical value in any test, the better the performance.

[0030]

[Table 1]

In all the test results, the tire of the present invention has excellent performance as compared with the conventional tire.

[0032]

Industrial Applicability The pneumatic tire of the present invention can maintain the tread land rigidity in a uniform state without lowering it, and at the same time improves the edge effect and the drainage property. We have made it possible to provide an all-weather tire that can be used even when driving on bad roads such as snow and ice.

[Brief description of drawings]

FIG. 1 is a development view of a tread 1 of a tire of the present invention.

FIG. 2 is a development view of a tread 2 of the tire of the present invention.

FIG. 3 is a development view of tread 3 of the tire of the present invention.

FIG. 4 is a development view of a tread 4 of a conventional tire.

[Explanation of symbols]

 1,2,3,4 Tread 5 Main groove 6 Secondary groove 7 Single notch 8 Branch notch 9 Block-shaped land portion 10 Trunk notch 11 Branch notch 12 Composite notch 13 First minor groove 14, 15, 16 Region 17 Second minor Groove 18, 19 Block 20 Third auxiliary groove 21 Fourth auxiliary groove 22, 23 Main groove constituent A, B block

Claims (1)

[Claims] 1. A tire having a tread including a block-shaped land portion divided by a plurality of main grooves and a plurality of sub-grooves communicating with the main groove, wherein the block-shaped land portion has the main groove or A composite notch that includes a main notch that extends from the sub-groove and that has a tip that stays in the land substance, and a branch notch that extends from the main notch to both sides in different directions and that has a tip that stays in the land substance. Pneumatic tire characterized by.