JPH02212204A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To improve the performance on ice and snow by setting a distance between sipe sets along the circumference of a tire and a distance between the circumferential end of a block and each sipe close to it larger than a tire circumferential distance between sipes in each set. CONSTITUTION:A tread pattern consisting of blocks 1 is formed in a tire tread surface 10. A plurality of sipes 2 (22, 22) are disposed along a tire width direction F-F' in the surface of the block 1. In this case, in a sectional area of the block 1 for a tire circumferential direction E-E', a tire circumferential distance between one set of sipes 22, 22 and another set of sipes 22, 22 is set larger than a tire circumferential distance (d) between the sipes 22, 22 in each set. A tire circumferential distance between the circumferential end of the block 1 and each sipe 22 closest to this circumferential end is set larger than the tire circumferential distance (d) between the sipes in each set.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pneumatic tire with improved braking performance on ice and snow.

(Prior art) Conventionally, the block surface of the tread of a pneumatic tire has a seventh
As shown in Figure (A), a plurality of sipes were provided at appropriate intervals.

FIG. 7(A) is an explanatory cross-sectional diagram in the tire circumferential direction of blocks on the tread of the tire when it is new. In FIG. 7(A), sipes 2 are provided on the surface of block l. 3 is the ground plane. When running, the tire provided with sipes rotates in the direction of arrow t and moves in the direction of arrow T, as shown in FIG. 7(B). In this case, block 1
Since the kicking side of the foot leaves the contact surface 3 later than the stepping side, so-called heel-and-toe wear occurs, in which the kicking side wears out more than the stepping side. When heel-and-toe wear occurs, the initial stage of wear
Braking performance on ice and snow deteriorates towards the middle of wear, and this tendency is particularly pronounced in the case of tires mounted on non-driving wheels.

[Problem to be solved by the invention]

An object of the present invention is to provide a pneumatic tire with improved braking performance on ice and snow by devising sipes provided on the block surface of the tire tread.

[Means to solve the problem]

The present invention provides a tire in which a plurality of sipes are provided in the tire width direction on the block surface of the tire tread, in which two or more sipes are made into one set, and the distance between these sets in the tire circumferential direction and the circumferential direction of the block The gist is a pneumatic tire characterized in that the distance between the end and the set closest to the circumferential end among these sets is larger than the distance in the circumferential direction of the tire between the sipes in each set. .

This means will be explained in detail below with reference to the drawings. Note that the same parts and parts as in FIGS. 7(A) and 7(B) are indicated by the same numbers.

FIG. 1 is an explanatory plan view of an example of a tread pattern formed on the tread surface of the pneumatic tire of the present invention. In FIG. 1, a tread pattern consisting of blocks 1 is formed on a tread surface 10. A plurality of sipes 2 are provided on the surface of the block 1 in the tire width direction FF". Regarding this sipe 2, two sipes 2□, 2□ form a pair. m is the tire equator The line indicates the width of the tire tread, and W indicates the tire tread width.

Figure 2 shows the tire circumferential direction EE of block 1 in Figure 1.
' shows an enlarged cross section. In FIG. 2, the distance in the tire circumferential direction between these sets, that is, the distance 12 in the tire circumferential direction between one set of sipes 2z-2t and the other set of sipes 2□, 2□ is It is larger than the tire circumferential direction distance d between the inner sipes 2□ and 22 (12>d).

Further, the distances Ml+ and lz between the circumferential end of the block 1 and the set closest to the circumferential end among these sets are Sipe 2□ in the set, respectively.

2 is larger than the tire circumferential distance d between (1
．． >d, l, >d). In this way, 11>d, 1. >d,
The one who made l,>d is Sipe 2 in the group! , 2□ is made lower than the block rigidity of other parts. 11, lt, and l, where l is the smallest value, it is preferable that d and l satisfy the following relationship.

115 J<d< l/31 If d is less than 115 J, d becomes too narrow and Sipe 2 in the group! , the block part between 2□ is torn apart when worn. Also, if d is l/31 or more, Sipe 2□, 2! in the group! This is because the space between the two sipes becomes too wide, causing heel and toe wear on the block between the two sipes.

FIGS. 3 and 4 respectively show abrasion of the trend pattern formed on the tread of the pneumatic tire of the present invention. FIG. 3 shows three sipes 2□, 2□, 2. This is the case where there is one set. FIG. 4 shows a case where the shape of the block 1 in plan view is different from that in FIG. 1.

In the present invention, two or more sipes are connected to 1&I in this way.
When the sipes 2t and 2 are placed on the surface of the block 1 as shown in FIG. 5(A), the block portion a between them is flush with the other portions, but B
), when the tire rotates in the direction of arrow t and moves in the direction of arrow T when running, the rigidity of block part a is lower than that of other parts, so it wears out more than other parts. Hateful. Therefore, as the other parts wear out, the block part a will pop out a little.

Therefore, in a conventional pneumatic tire in which a plurality of sipes are independently provided on the surface of the block l at appropriate intervals, the tire travels on ice and snow in the direction of the arrow T, as shown in FIG. 6(A). In this case, heel-and-toe wear occurs, resulting in a decrease in braking performance on ice and snow, as described above.In contrast, in the pneumatic tire of the present invention, as shown in Figure 6 (B), the braking performance on ice and snow decreases. When moving in the direction of arrow T on ice and snow, block part a slightly protrudes as other parts wear out, so the tip of block part a exerts an edge effect during braking, so it is difficult to prevent wear from the early stages of wear.
No deterioration in braking performance on ice or snow is observed towards the middle stage of wear.

〔Effect of the invention〕

As explained above, according to the present invention, a plurality of sipes are provided on the block surface of the tire tread in the tire width direction, two or more sipes are made into one set, and the tire circumferential direction between these sets is Since the distance and the distance between the circumferential end of the block and the set closest to the circumferential end among these sets were each made larger than the tire circumferential distance between the sipes in the set, It is possible to prevent the deterioration of braking performance on ice and snow during the middle stage of wear.

Therefore, according to the present invention, the pneumatic tire of the present invention that makes it possible to improve braking performance on ice and snow is particularly suitable for tires mounted on non-driving wheels where heel-and-toe wear is likely to occur. It is.

[Brief explanation of the drawing]

FIG. 1 is an explanatory plan view of an example of a tread pattern formed on the tread of a pneumatic tire of the present invention, FIG. 2 is an explanatory diagram showing an enlarged tire circumferential cross section of the block in FIG. FIG. 4 and FIG. 4 are plan view explanatory diagrams showing abrasion of the trend pattern formed on the tread of the pneumatic tire of the present invention, respectively. FIG. 5(A) is an explanatory diagram of a cross section in the tire circumferential direction of the block of the tread when the pneumatic tire of the present invention is new, FIG. 5(B) is an explanatory diagram of a cross section in the circumferential direction of the tire when the tire is worn, and FIG. A) is a tire circumferential cross-sectional explanatory diagram showing the block shape of a conventional pneumatic tire during braking, and FIG. 6(B) is a tire circumferential cross-sectional explanatory diagram showing the block shape of the pneumatic tire of the present invention during braking. , FIG. 7(A) is an explanatory view of a tire circumferential cross-section of a block on the tread of a conventional pneumatic tire when it is new, and FIG. 7(B) is an explanatory view of a tire circumferential cross-section when the tire is worn. 1...Block, 2.2! ... Sipe, 3... Ground plane. Agent Patent Attorney Nobuo Ogawa −

Claims (1)

[Claims] In a tire in which a plurality of sipes are provided in the tire width direction on the block surface of the tire tread, two or more sipes are considered as one set, and the circumferential distance between these sets and the circumferential end of the block and these A pneumatic tire characterized in that the distance between the pair closest to the circumferential end of the pairs is greater than the distance in the tire circumferential direction between the sipes in each pair.