JP3347276B2 - Tire tread pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tread pattern of a pneumatic tire used for trucks and buses, agricultural use, off-road use, racing use, and the like.

[0002]

2. Description of the Related Art In a tread pattern of this type of pneumatic tire, as disclosed in Japanese Utility Model Laid-Open Publication No. 63-128102, a large number of blocks are formed at intervals in the tire axial direction and the tire circumferential direction. This block is formed into a polygon such as a hexagon, and each block is formed with a narrow groove in the tire axial direction that is opened from the middle of the block to the sea portion (first block).
As disclosed in JP-A-58-93609, a large number of lands defined by main grooves (sea portions) are formed at intervals in the tire axial direction and the tire circumferential direction. The land portion is formed into two polygonal blocks defined by sub-grooves in the tire axial direction or the tire circumferential direction, and the two blocks are connected by a shelf at the bottom of the sub-groove (second conventional technique). , Etc.

[0003]

In the first prior art, since the block is formed in a substantially hexagonal shape and a narrow groove is formed in the tire axial direction, a force (side slip force) in all directions is provided.
, But to fully demonstrate this ability,
It is necessary to increase the number of blocks per unit area, and if it is increased, the blocks will become smaller and their durability will decrease, and the narrow grooves will be clogged with mud and grass, making it difficult to remove I have.

In the second prior art, the land portion is formed by two polygonal blocks, and both blocks are connected by the shelf at the bottom of the sub-groove dividing the land portion. Although the main groove and the sub-groove are almost in the tire axial direction or the tire circumferential direction in the main groove and the sub-groove, it is difficult to cope with skidding, and the two blocks are in the tire axial direction or the tire. Since they are arranged along the circumferential direction, it is difficult to expect the ability to cope with the sideslip due to the shape of the land portion.

In view of the problems of the prior art, the present invention can maintain the durability of the block at a high level, can cope with forces in all directions, can improve not only front and rear traction but also the ability to cope with skidding, It is an object of the present invention to provide a tire tread pattern that can reduce clogging.

[0006]

The first concrete means for solving the problems in the present invention is to arrange lands 3 defined by the main grooves 2 at intervals in the tire axial direction A and the tire circumferential direction B. A large number of the lands 3 are formed in two polygonal blocks 5 defined by the sub-grooves 4, and the two blocks 5 are connected by a shelf 6 at the bottom of the sub-groove 4. A narrow groove 7 opened from the side to the sub-groove 4 is formed, and the arrangement direction of the main groove 2, the sub-groove 4 and the two blocks 5 is inclined with respect to the tire axial direction A.

As a result, not only the shape of the polygonal block 5 but also the shape of the land 3 having the two blocks 5 and the arrangement direction of the blocks 5 can cope with forces in all directions. The ability to respond to skidding has also improved, and the durability of the block 5 has been maintained at a high level.
It facilitates movement around the narrow groove 7 and reduces clogging of the narrow groove 7.

A second concrete means for solving the problem in the present invention is that, in addition to the first concrete means, the inclination angle C in the arrangement direction of the two blocks 5 is set with respect to the tire axial direction A. That is, the angle is set to 30 to 40 degrees. Thus, the ability of the land portion 3 having the two blocks 5 to cope with the side slip is further enhanced.

According to a third concrete means for solving the problems in the present invention, in addition to the first or the second concrete means, each of the polygon blocks 5 has at least five sides, and One or two sides are substantially parallel to the tire axial direction A, and the length F of the side is the tire axial length D of one block 5.
Is set to 30 to 40%. Thereby, the length of the side of the polygon block 5 substantially parallel to the tire axial direction A is suppressed to be short, and the ability of the other side to cope with sideslip is further increased.

A fourth concrete means for solving the problems in the present invention is that, in addition to any one of the first to third concrete means, each side of each polygonal block 5 has a flat surface, a concave surface or a concave surface. That is, it is formed on a convex surface. Thus, the polygon block 5 can be easily formed by forming each side on a flat surface, and can be formed on a concave surface or a convex surface to lengthen an edge to further enhance traction and skidding capability.

According to a fifth concrete means for solving the problems in the present invention, in addition to the first concrete means, the length G of the narrow groove 7 is the length D of one block 5 in the tire axial direction. 3
0 to 50%, the width H is 10 to 15% of the tire circumferential length E of one block 5, and the depth J is 40 to 90% of the depth K of the main groove 2.
That is, they are set to 80%. Thereby, the narrow groove 7 is formed in an appropriate shape, the traction and the side slipping ability are further improved, and clogging of mud and grass is reduced.

A sixth concrete means for solving the problem in the present invention is that, in addition to the first or the fifth concrete means, the narrow groove 7 is substantially parallel to the main groove 2 and the sub groove 2 along the tire axial direction A. Groove 4
And that the point of intersection is roughly oriented. by this,
This makes it easy to move around the narrow groove 7 and facilitates the removal of mud and turf that has entered the narrow groove 7 to more reliably reduce the clogging of the narrow groove 7.

According to a seventh concrete means for solving the problems in the present invention, in addition to the first concrete means, the width M of the sub-groove 4 is 40 to 70% of the width L of the main groove 2, Depth N is main groove 2
Is set to 40% to 80% of the depth K of the image. As a result, the two polygonal blocks 5 are firmly connected by the shelf 6 having an appropriate height, and mutual reinforcement is possible.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. In the first embodiment shown in FIGS. 1 to 3, reference numeral 1 denotes a tread of a tire, and a main groove (sea portion) 2.
Are formed in the tire axial direction A and the tire circumferential direction B at intervals in the tire axial direction A.
Are arranged in a total of three rows on the equator and both sides thereof, and a part thereof is formed on the right and left shoulders 9.

The land 3 has two polygonal blocks 5 defined by sub-grooves 4, and the two blocks 5
Each block 5 is formed with a narrow groove 7 which is open from the middle of the block to the sub-groove 4.
The two blocks 5 of each land 3 are arranged in the arrangement direction (2
The direction of the line connecting the center positions of the two blocks 5) is substantially the same as the direction of displacement of the land portions 3 in the adjacent row (indicated by a dashed line in FIG. 2), and only the inclination angle C with respect to the tire axial direction A The inclination angle C is, for example, 30 to 40 °.
Is set to The land 3 in each row is shifted in the tire circumferential direction B with respect to the land 3 in the adjacent row.

Therefore, the main groove 2 also becomes a groove substantially parallel to the arrangement direction of the two blocks 5 and a groove substantially perpendicular thereto, and these are inclined with respect to the tire axial direction A. The sub-groove 4 is also inclined. The block 5 is a polygon having approximately eight faces, two sides a are substantially parallel to the tire axial direction A, and the length F of the side a is 30 of the length D of one block 5 in the tire axial direction. Set to ~ 40%,
Similarly, the other sides b, c, d, etc. have a length D of 3 in the tire axial direction.
It is set to 0 to 40%.

The sides a and c have a flat surface facing the main groove 2, while the side b has a slightly concave concave surface.
This concave surface may be flat or arcuate. Side c is side b
When viewed from above, it has a convex shape having a flat surface, and this convex surface may also be formed as an arc surface protruding toward the main groove 2. Side d is side a
Is depressed similarly to the side b, and when the side a is viewed from the sides b and d, it protrudes in a square block shape.

One narrow groove 7 is formed in each block 5, and the length G of the narrow groove 7 is 30 to 50% of the length D in the tire axial direction of one block 5, and the width H is One block 5 has a tire circumferential length E of 10 to 15%, and a depth J of the main groove 2 has a depth K of 40 to 80%. The narrow groove 7 is located on the side opposite to the side c and the tire circumferential direction B and between the two sides d, and is formed in a direction substantially along the tire axial direction A from the center position of the block 5 or the vicinity thereof to the sub groove 4, The opening opened to the sub-groove 4 is expanded toward the sub-groove 4. The narrow groove 7 is in a direction substantially along the tire axial direction A, and the arrangement of the two blocks 5 is inclined, and as shown in FIG. The intersection is substantially directed, and the narrow grooves 7 of the two blocks 5 are shifted from each other in the tire circumferential direction B.

The width M of the sub groove 4 is 40 times the width L of the main groove 2.
The depth N is set to 40 to 80% of the depth K of the main groove 2, and the depth is made the same as that of the narrow groove 7 in FIG. It is preferable that the depth of the narrow groove 7 is shallower than the sub-groove 4. When the depth N of the sub-groove 4 is 40 to 80% of the depth K of the main groove 2, the height of the shelf 6 formed at the bottom of the sub-groove 4 is 20 times the depth K of the main groove 2. ６０60%, and the two blocks 5 are firmly connected.

In each block 5, a pair of sipe 10 having a U-shape substantially along the side b is formed in a C-shape, and both the sipe 10 and the narrow groove 7 have a substantially triangular arrangement. Has become. Both ends of each sipe 10 are not open to the main groove 2. In the second embodiment shown in FIGS. 4 and 5, the shape of the block 5 is different from that of the first embodiment, and accordingly, the shapes of the main groove 2 and the sub-groove 4 are slightly modified.

Two blocks 5 forming each land 3
Is a polygon having approximately eight faces, and each of the sides a to d is a flat surface without irregularities. However, the sides b and c can be regarded as one side of a convex shape. 5 is a hexagon, and two sides a (or one side) are formed substantially parallel to the tire axial direction A. The land portions 3 may be arranged in two or four or more rows in the tire axial direction A,
Considering the balance between the size of the block 5 and the area of the main groove 2, a land area that is optimal for the purpose of use and that can maintain high durability is set.

The arrangement direction of the two blocks 5 can be reversed (the land portions 3 are arranged in a V shape) with the equator as a boundary. Can be good. It is also possible to make the arrangement direction of the two blocks 5 different from the shift direction of the land portions 3 in the adjacent row. Although the inclination angle C in the arrangement direction can be set to an angle other than 30 to 40 °, this inclination angle is the most preferable in order to improve the ability to cope with sideslip while exerting front and rear traction. Since the block 5 is shifted in the tire circumferential direction B, one of the two sides d can face the main groove 2, and the ability to cope with a side slip can be further improved.

The block 5 may be a polygon having five or more faces, and one side substantially parallel to the tire axial direction A may be one side,
The front and rear traction can also be obtained at the edge of the narrow groove 7, and the side slipping ability can be obtained at the side d. Side b of the block 5
As for d, when the concave surface and the convex surface are alternately formed, not only the edge length is increased, but also the front-rear traction and the side slip response ability can be improved depending on the shape of the corner.

Although two or more narrow grooves 7 can be formed in one block 5, it is preferable to form one in a shape to reduce clogging of mud, turf and the like. Further, the narrow groove 7 can be formed at a portion other than between the sides d, sides a to c or between them, and formed so as to be open to the main groove 2 side. Since the surrounding area is easily deformed, which leads to a reduction in the strength of the block 5, the position where the two blocks 5 face the sub-groove 4 where the two blocks 5 are reinforced with each other is most preferable.

When the length G is made shorter than 30% of the length D in the tire axial direction of the block 5 or when the depth J is made shallower than 40% of the depth K of the main groove 2, the narrow groove 7 is formed in front and rear. Lack of traction, length G longer than 50% of tire axial length D, width H larger than 15% of tire circumferential length E of block 5 and depth J of main groove 2 Depth K of 80
%, The strength of the block 5 is excessively reduced, and when the width H is smaller than 10% of the length E in the circumferential direction of the tire, clogged mud, grass and the like are difficult to appear.

The narrow groove 7 is formed in a direction substantially along the tire axial direction A.
By increasing the length of the two sides a to obtain sufficient front and rear traction, the narrow groove 7 is inclined with respect to the tire axial direction A to improve the ability to cope with side slip. It can also be done. The narrow grooves 7 of the two blocks 5 can be made to coincide with the tire circumferential direction B, but it is better to shift them so that the intersection of the main groove 2 and the sub-groove 4 is directed substantially to remove mud, turf and the like. Clogging can be further reduced, and narrow grooves 7
Can be arranged substantially at the center of each block 5 in the tire circumferential direction B, so that the durability of the block 5 can be maintained high.

The width M of the sub-groove 4 is set to 40 times the width L of the main groove 2.
%, Or the depth N is made shallower than 40% of the depth K of the main groove 2, it becomes difficult to expect the edge effect and the earth discharging performance by the side d of the block 5, and the width M becomes smaller than the main groove 2. Width L
And the depth N is set to 8 of the depth K of the main groove 2.
If the depth is made 0% or more, it becomes difficult to expect the connection strength of the two blocks 5 by the shelf 6 and the mutual reinforcing property of the two blocks 5.

The sipe 10 can be deformed in a well-balanced manner over the entire area of the block 5 by arranging the sipe 10 in a substantially triangular shape with the narrow groove 7. However, the position, shape and the like may be changed. It is also possible to open it.

[0029]

According to the present invention described above, not only the shape of the polygonal block 5 but also the shape of the land 3 having the two blocks 5 and the arrangement direction of the blocks 5 can cope with forces in all directions. As a result, not only the front and rear traction but also the ability to cope with sideslip can be improved, the durability of the block 5 can be maintained high, the periphery of the narrow groove 7 can be easily moved, and the clogging of the narrow groove 7 can be reduced.

Further, the ability of the polygon block 5 to cope with skidding can be further improved by the shape of the land 3 having the two blocks 5 and by reducing the length of the side of the polygon block 5 substantially parallel to the tire axial direction A. . Furthermore, the polygon block 5 can be easily formed by forming each side on a flat surface, and by forming it on a concave surface or a convex surface, the edge can be lengthened to further enhance the traction and side slip response ability.

Further, the narrow groove 7 is formed in an appropriate shape and forming direction, so that it is easy to move around the narrow groove 7, the traction and the ability to cope with a side slip can be further improved, and the mud and turf that has entered can be eliminated. By making it favorable, clogging of the narrow groove 7 can be more reliably reduced. Further, the two polygonal blocks 5 can be firmly connected by the shelf portion 6 having an appropriate height, and mutual reinforcement can be enabled.

[Brief description of the drawings]

FIG. 1 is an enlarged plan view of a land portion according to a first embodiment of the present invention.

FIG. 2 is an overall plan view of the same.

FIG. 3 is an enlarged front view of the land portion.

FIG. 4 is a plan view showing a second embodiment of the present invention.

FIG. 5 is an enlarged plan view of the land portion.

[Explanation of symbols]

 Reference Signs List 1 tread of tire 2 main groove 3 land 4 sub-groove 5 block 6 shelf 7 narrow groove A tire axial direction B tire circumferential direction C inclination angle

Claims (7)

(57) [Claims] A land portion (3) defined by a main groove (2).
Are formed at intervals in the tire axial direction (A) and the tire circumferential direction (B), and the lands (3) are formed into two polygonal blocks (5) defined by the sub-grooves (4). And 2
Blocks (5) are connected by a shelf (6) at the bottom of the sub-groove (4), and each block (5) is connected to the sub-groove (4) from the middle of the block.
The main groove (2), the sub-groove (4), and the arrangement direction of the two blocks (5) are inclined with respect to the tire axial direction (A). A tread pattern of a tire, wherein an inclination angle (C) in the arrangement direction of the blocks (5) is set to 30 to 40 degrees with respect to the tire axial direction (A). 2. The narrow groove (7) is provided in the tire axial direction (A).
The tread pattern of a tire according to claim 1, wherein the intersection of the main groove (2) and the sub-groove (4) is substantially directed while substantially along the line. 3. A land portion (3) defined by a main groove (2).
Are formed at intervals in the tire axial direction (A) and the tire circumferential direction (B), and the lands (3) are formed into two polygonal blocks (5) defined by the sub-grooves (4). And 2
Blocks (5) are connected by a shelf (6) at the bottom of the sub-groove (4), and each block (5) is connected to the sub-groove (4) from the middle of the block.
A groove (7) that is open to the main groove (2), the sub-groove (4), and the arrangement direction of the two blocks (5) are inclined with respect to the tire axial direction (A). (7) The main groove (2) and the sub-groove (4) substantially along the tire axial direction (A).
The tread pattern of the tire, characterized in that the intersection with the tire is substantially directed. 4. Each of said polygonal blocks (5) is at least
Also has five sides, and one or two of the five sides are in the tire axial direction.
It is substantially parallel to (A) and the length of its side (F) is one
30 to 4 of the tire axial length (D) of the block (5)
4. The method according to claim 1, wherein the value is set to 0%.
The tread pattern of the tire described in any of the above. 5. Each side of each of said polygonal blocks (5) is:
Characterized by being formed on a flat surface, concave surface or convex surface
The tread pattern of the tire according to claim 1 . 6. The length (G) of said narrow groove (7) is one
30 to 50 of the axial length (D) of the block (5)
%, Width (H) is the circumferential length of one block (5)
10 to 15% of the depth (E), and the depth (J) is the depth of the main groove (2).
40-80% of (K)
The tire tread pattern according to any one of claims 1 to 5, wherein 7. The width (M) of the sub-groove (4) is equal to the width of the main groove.
(2) 40-70% of width (L), depth (N) is main groove
(2) 40 to 80% of the depth (K)
The tread pattern of a tire according to any one of claims 1 to 6, wherein