JPH01132406A - Pneumatic radial tyre - Google Patents

Abstract

PURPOSE:To enhance abrasion resistance without reducing heel and toe abrasion and the like by arranging blocks which satisfy specific relation and have shallow grooves with cipes, in the direction that the cipes cross the tyre circumferential direction. CONSTITUTION:Blocks 1 having shallow grooves 2 with cipes 3 on the groove bottoms thereof are formed on a tyre tread surface, and respective blocks 1 are arranged in the direction that the cipes 3 cross the circumferential direction of the tyre. In this tyre, the length in the tyre circumferential direction of every block 1 is set to be at least 1% of tyre circumferential length and as well the depth of the shallow groove 2 is set to be within a range of 10-20% of a main groove 4 depth and also its width is set to be within a range of 5-15% of the length in the circumferential direction of the block 1. Further, the sum of the depth of the shallow groove 2 and that of the cipe 3 is set to be at least 60% of the depth of the main groove 4. With this arrangement, heel and toe abrasion performance and snow traction are prevented to be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pneumatic radial tire with improved wear resistance without reducing heel-and-toe wear or snow traction.

[Conventional technology]

Conventionally, it has been known that increasing the size of the blocks formed on the tire tread surface improves wear resistance, but has the drawback of decreasing snow traction and heel-and-toe wear resistance.

To overcome this drawback, there are tires in which the number of sipes formed on the block is increased in proportion to the size of the block. For example, FIG. 2 is a partial plan view showing an example of the tread pattern of a normal radial tire consisting of a relatively large block 1 with sipes 2 formed thereon, and FIG. 3 is a partial plan view showing an example of a tread pattern of a tire in which the number of sipes 2 is formed. As shown in FIG. 3, in the case of a tire in which the number of sipes provided on the block surface is simply increased There was a tendency for steering stability to deteriorate.

[Purpose of the invention]

The object of the present invention is to improve the drawbacks of the conventional tires mentioned above.
To provide a pneumatic radial tire that has excellent wear resistance and good handling stability without reducing heel-and-toe wear or snow traction.

[Structure of the invention]

Such an object of the present invention is achieved by arranging a block having a shallow groove with sipes provided at the groove bottom that satisfies the following relationships (1), (2), and (3) in a direction in which the sipes cross the tire circumferential direction. Can be done.

■ The length of the block in the circumferential direction of the tire is at least 1% of the circumferential length of the tire; ■ The depth of the shallow groove is within a range of 10 to 20χ of the depth of the main groove, and the width thereof is The circumferential length of the block is within the range of 5 to 15x, and (1) the sum of the depth of the shallow groove and the depth of the sipes or the depth of the main groove is at least 60x.

EMBODIMENT OF THE INVENTION Hereinafter, the pneumatic radial tire (hereinafter referred to as tire) according to the present invention will be described in detail with reference to the drawings.

FIG. 1A is a plan view showing an example of the tread pattern of the tire of the present invention, and FIG. 1B is an enlarged cross-sectional view of the part M marked with ○ in FIG. A cross section showing the shallow grooves and sipes of the block. In the figure, ■ indicates a block, 2 indicates a sipe, 3 indicates a shallow groove, 4 indicates a main groove, 5 indicates a minor groove, and TDΔ indicates a trend.

As shown in the figure, the tire tread surface of the present invention includes a block 1 having a shallow groove with a knife formed in the groove bottom, and the block 1 has the sipe arranged in a direction transverse to the circumferential direction of the tire. ing. These blocks, shallow grooves, and sipes must satisfy the relationships (1) to (2) described above.

That is, one of the features of the present invention is that the block 1 is provided with a shallow a3 having sipes 3 at the groove bottom, and even if only the shallow groove 2 is provided in the block 1 alone, the present invention cannot achieve its purpose. This block 1 is
It is necessary that the block 1 has a relatively large shape, that is, the length (N) in the tire circumferential direction is at least 1χ of the tire circumference, and for a tire having such a relatively large block 1, This allows the effects of the present invention to be better exhibited. The length of this block in the tire circumferential direction I
t) is preferably within the range of 1.0 to 2.5'A.

The depth of the shallow groove 2 provided in the block 1 is within the range of 10 to 20 χ of the depth of the main groove 4, and the width thereof is 5 to 15 χ of the circumferential length (1) of the block 1. This is very important. Here, the depth of the main groove 4 is determined by a standard for each tire size for boat fishing. However, the depth may be within the range of the main groove provided in a normal radial tire, and is not particularly limited, but may be between 10.0 mm and 15 mm.
．． It can be appropriately selected within the range of 0 mm.

However, the depth of the shallow groove 2 provided in the block 1 is within the range of 10 to 20% of the depth of the main groove 4, and the width thereof is the circumferential length (1) of the block 1. 5~15χ
It is necessary that

If the depth and width of this shallow groove 2 are smaller than the above range, it will not have a sufficient effect on heel and toe wear resistance, while if it is larger than the above range, handling stability will decrease. Undesirable.

The length of the shallow groove 2 is not particularly limited, but may be a length that occupies at least 50x of the width of the block 1 (width in the direction transverse to the tire circumferential direction). The number of shallow grooves 2 in the block 1 depends on the shape and length of the shallow grooves 2, but is within the same range as the number of sipes provided in the block of a normal radial tire, for example, in the range of 1 to 3. One is selected as appropriate.

Length of the sipe 3 provided at the bottom of the shallow groove 2 of the present invention
The width (width) is the same as or less than the length (width) of the shallow groove 2, and the depth differs depending on the depth of the main groove 4 and the shallow groove 2, and is different from the depth of the shallow groove 2. The sum of the depth of the sipe 3 or the depth of the main groove 4 is 60% or more.

〔Example〕

EXAMPLES Hereinafter, the present invention and its effects will be explained in more detail with reference to Examples.

Example 1 Four types of trial tires shown in Table 1 were manufactured, and the heel and toe wear performance and steering stability of these tires were measured, and the results shown in Table 2 were obtained.

Heel-and-toe wear performance and handling stability are based on feeling evaluations through actual vehicle tests.

(Hereinafter, blank space) Table 1 Depth of main groove: 12.6 mm in each case Table 2 [Effects of the invention] According to the present invention, the heel-and-toe wear performance and the It is possible to prevent a decrease in snow traction.

[Brief explanation of the drawing]

FIG. 1A is a plan view showing an example of the tread pattern of the tire of the present invention, FIG. 1B is an enlarged cross-sectional view of the instep M of FIG. 1A, and FIGS. FIG. 3 is a partial plan view of a tire trend pattern of FIG. 1...Block, 2...Shallow groove, 3...Sipe, 4
...Main groove, 5...Minor groove. Agent Patent Attorney Nobuo Ogawa −

Claims (1)

[Claims] 1) A block having a shallow groove with sipes provided at the groove bottom that satisfies the following relationships (1), (2), and (3) is arranged in a direction in which the sipes cross the circumferential direction of the tire. A pneumatic radial tire. (1) The length of the block in the tire circumferential direction is at least 1% of the tire circumference, (2) The depth of the shallow groove is within the range of 10 to 20% of the main groove depth. , and its width is 5 to 15 of the circumferential length of the block.
(3) the sum of the shallow groove depth and the sipe depth is at least 60% of the main groove depth.