JPH02169307A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To prevent the rear edge part of the treading side from being floated at the time of damping by providing multiple thin notches intersecting the circumferential direction of a tire to multiple blocks forming a tread pattern at a specified position from the edge part on the treading side. CONSTITUTION:On the tread surface of a tire, a block pattern consists of many blocks 3 separated by main grooves 1 in the circumferential direction (E-E') of the tire and sub-grooves 2 in the direction intersecting it. In this instance, multiple thin notches 4 are one-sidedly formed on the blocks 3. And, in the rotational direction of the tire, thin notches 4R that are nearest to the edge part on the treading side R of the blocks 3 are formed at the position equivalent to the length 1 that is more than 1/3 and less than 1/2 of the length L in the circumferential direction at the blocks 3. Also, the thin notches 4 in the remaining portion are provided at proper pitches p between the thin notches 4R positioned nearest to the edge part on the treading side R and the edge part on the kicking side F of the blocks 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a pneumatic tire in which thin cuts are formed in a block for the purpose of improving braking performance on icy and snowy roads.

[Conventional technology]

Conventionally, as shown in FIG. 4, a tire tread surface is made up of a large number of blocks 3 defined by a main groove 1 extending in the tire circumferential direction E-E' and a sub-groove 2 extending across the main groove 1. In the patterned pneumatic tire, each block 3 is provided with a plurality of thin notches 4 in a direction that intersects with the circumferential direction of the tire to improve the ground contact performance of the block 3. The effect provides braking performance on icy and snowy roads. As shown in FIGS. 4 and 5, the plurality of thin cuts 4 provided in the block 3 of this conventional tire usually have substantially the same pitch p and depth d. When braking, such a conventional tire blocks 3 as shown in FIG.
falls forward in the opposite direction to the traveling direction of the vehicle indicated by the white arrow, and the rear area of the block 3 that touches the ground, that is, the step-in side R, rises up, and the ground contact area of the block 3 decreases.

Therefore, in the case of conventional tires, braking performance on icy and snowy roads cannot be efficiently achieved by effectively utilizing all of the plurality of thin cuts 4.

[Problem to be solved by the invention]

An object of the present invention is to provide a pneumatic tire having the above-mentioned block pattern and having a plurality of thin cuts in the blocks, which maintains the excellent driving performance of a pneumatic tire while improving braking performance on icy and snowy roads. It is in.

[Means to solve the problem]

It is an object of the present invention to provide a pneumatic tire having a tread pattern formed by a plurality of blocks, in which at least two thin cuts formed in the blocks in a direction intersecting the circumferential direction of the tire are This can be achieved by providing a thin cut closest to the stepping-in end of the block at a distance Ml from the stepping-in end expressed by the following equation.

(1/3) L < 12≦(1/2) L In the above formula, L
indicates the length of the block in the tire circumferential direction.

Hereinafter, the present invention will be specifically explained based on the drawings.

As shown in FIG. 1, the tire of the present invention has a large number of blocks 3 defined on its tread surface by a main groove 1 extending in the tire circumferential direction E-E' and a sub-groove 2 extending across the main groove 1.
As shown in FIG. 1 and FIG. 2, which is a cross section taken along line AA' in FIG.
A feature is that the plurality of thin cuts 4 provided in the block 3 are formed biased toward one side of the block 3. That is, when the arrow direction is the tire rotation direction, the thin cut 41I closest to the R end of the block 3 on the stepping side is 1 of the tire circumferential length of the block 3.
The remaining thin cuts 3 are formed at positions corresponding to the length exceeding 73 and 1/2 or less, and the remaining thin cuts 3 are the thin cuts 41I located closest to the step-in side R end and the kick-up side F end of the block 3. They are provided at an appropriate pitch p (interval) between them.

When such a braking force is applied to the tire of the present invention, as shown in Fig. 3, the depression side R of the block 3 becomes difficult to lift off the road surface, and the ground contact performance of the block 3 is maintained, resulting in improved braking performance. be. In other words, since no thin cut 4 is formed at all in the section of the distance l defined by the above formula from the end of the step-in side R of the block 3, the rigidity of the step-in side R is significantly greater than that of the kick-up side F of the block 3. big. Therefore, the highly rigid treading side R of the block 3 does not lift off the road surface even when braking force is applied, unlike conventional tires, and the ground contact area of the block does not decrease, improving the braking performance of the tire. It is.

The thickness of the thin cut provided in the block of the tire of the present invention,
The depth, the inclination angle of the cut with respect to the tread surface, etc. are not particularly limited, and can be appropriately selected and formed depending on the type of tire, the size and shape of the block, etc.

Pitch p (distance) of the notch formed between the thin notch 4i closest to the stepping side R and the kicking side F end
Although not limited to this, it is usually preferable to set them at equal intervals.

Note that this thin cut is preferably formed so that both ends thereof communicate with the main groove forming the block, but it is also possible to only communicate with at least one end of the cut.

Further, the direction of the thin cut is preferably perpendicular to the tire circumferential direction, but it may be slightly inclined within a range that does not impede braking performance or drivability. Preferably, the angle is 30'' or less with respect to the tire circumferential direction, and the shape thereof may be a straight line, a curved line, or a broken line.

The present invention will be specifically described below by comparing Examples with conventional examples and comparative examples.

The braking performance and snow pitching performance were evaluated by the following method.

M hard work: Test tires were mounted on all wheels of a large vehicle (2/D), and braking was applied from 40 km/h on a snow-compacted road surface, the braking distance was measured, and the results were displayed as an index. The larger this index is, the better the braking performance is.

1" J111 seed: A test tire was attached to the drive wheel of a large vehicle (2/D), and the time required to climb up a slope of a snow-compacted road at an initial speed of 30 km/hour over a 200 m section was measured, and the time was calculated as an index. displayed. The larger this index is, the better the pitching performance on snow is.

Embodiment, Conventional Example The block has the block pattern shown in FIG. A tire with a thin notch (closest to the stepping-in side end), and two thin notches with a pitch p of 8n+m and a depth d of 15 mm between this thin notch and the kicking-up side end. Size is 10.00R
A 2014PH tire of the present invention was created, and its braking performance and hill climbing performance were evaluated.

For comparison, the braking performance and braking performance of a conventional tire that is the same as the tire of the present invention, except that it has the block pattern shown in FIG. Pitching performance was evaluated. The results are shown in the table.

(Margins below this page) From the table, it can be seen that the tire of the present invention maintains the same climbing performance as the conventional tire, and has significantly improved braking performance compared to the conventional tire.

〔Effect of the invention〕

According to the present invention, in a pneumatic tire that has a block pattern on the tread surface and a plurality of thin cuts in the blocks, the thin cuts are not provided at the same pitch along the circumferential direction of the tire, but when the tire rotates. By forming the block biased towards the kick-up side and increasing the rigidity on the stepping side of the block, this prevents the rear end of the stepping side from lifting up when the block falls forward during braking. This prevents a decrease in the ground contact area of the block and improves braking performance on icy and snowy roads.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of the block pattern of the tire of the present invention, FIG. 2 is a sectional view taken along the line AA' in FIG. 4 is a plan view showing an example of a trend pattern of a conventional tire; FIG. 5 is a sectional view taken along line B-B' in FIG. 4; and FIG. 6 is a conventional tire. FIG. 3 is a cross-sectional view showing the deformation of the block during braking of the tire. 1... Main groove, 2... Minor groove, 3... Block, 4...
...Thin cut, F...Kicking side, R...Stepping side.

Claims (1)

[Scope of Claims] A pneumatic tire having a tread pattern formed by a plurality of blocks, in which the blocks are provided with at least two thin cuts in a direction intersecting the circumferential direction of the tire, and the blocks are depressed when the tire rotates. A pneumatic tire characterized in that a thin cut closest to the side edge is provided at a distance l from the depression side edge as expressed by the following formula. (1/3)L<l≦(1/2)L In the above formula, L indicates the length of the block in the tire circumferential direction.