JP2005186649A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire which can give an excellent braking performance on ice even if a vehicle is provided with an antilock brake system (ABS) mechanism. <P>SOLUTION: In the pneumatic tire having a large number of blocks 4 defined by longitudinal grooves 2 formed on a tread surface 1 so as to elongate in the peripheral direction T of the tire and a plurality of lateral grooves 3 crossing the longitudinal grooves 2, a large number of dimples 5 having a depth of 0.1 to 0.5 mm and a surface area of 0.7 to 15 mm<SP>2</SP>are dispersively arranged on the surfaces of the blocks 4, and further the dimples 5 are mutually connected with three or more shallow grooves 6 having a depth and a width of 0.1 to 0.5 mm, respectively. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire excellent in braking performance on ice suitable for a vehicle equipped with an ABS braking mechanism.

Conventionally, a vehicle studless tire equipped with an ABS braking mechanism has a problem that its braking performance on ice is low due to chemicals adhering to the tread surface from the beginning to the beginning of wear when the surface is peeled off. As a technique for suppressing such a decrease in braking performance on ice from the beginning of the tire to the initial stage of wear, a water film is formed between the ice road surface and the tread surface by forming a fine concave or convex portion on the tread surface. There is a proposal that removes (see, for example, Patent Document 1)
However, in ABS braking, the tire rotates during braking on the road surface on ice and the tread comes into contact with the road surface in many ways, so that if the snow is clogged in the recess, the substantial contact area is reduced. There was a problem that could not be obtained.
JP 7-257111 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire that solves the conventional problems and can provide excellent braking performance on ice even in a vehicle equipped with an ABS braking mechanism.

In order to achieve the above object, a pneumatic tire of the present invention is a pneumatic tire in which a tread surface includes a plurality of blocks formed by longitudinal grooves extending in the tire circumferential direction and a plurality of lateral grooves intersecting the longitudinal grooves. A large number of dimples having a depth of 0.1 to 0.5 mm and a surface area of 0.7 to 15 mm ² are dispersed on the surface of the block, and the depth and width of the dimples are 0. It is connected by three or more shallow grooves of 1 to 0.5 mm.

  In the pneumatic tire of the present invention, a large number of dimples having a specific depth and surface area are dispersedly arranged on the surface of the block, and these are connected in a mesh pattern by three or more shallow grooves having a specific depth and width. Therefore, when snow slips during ABS braking on the road surface on ice, the snow and water film intervening between the road surface and the tread surface wraps the groove and guides it to the dimple side, and the ice snow clogged in the dimple is accompanied by the rotation of the tire. Discharge to the outside by centrifugal force. Therefore, when contacting the road surface on ice again, a new tread surface to which no snow is attached comes into contact, so that the ABS braking performance on ice can be improved.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a plan view showing an example of a tread surface of a pneumatic tire according to an embodiment of the present invention.

In FIG. 1, a plurality of blocks 4 are formed on a tread surface 1 of a pneumatic tire by a plurality of longitudinal grooves 2 extending in the tire circumferential direction T and a plurality of transverse grooves 3 intersecting the plurality of longitudinal grooves 2. As shown in FIG. 2, a large number of dimples 5 having a depth of 0.1 to 0.5 mm and a surface area of 0.7 to 15 mm ² are distributed on the surface of the block 4. They are connected in a mesh form by three or more (four in the figure) shallow grooves 6 having a depth and width of 0.1 to 0.5 mm. FIG. 3 shows a cross section taken along the line XX of FIG.

  By forming a mesh-like recess composed of the shallow dimple 5 and the shallow groove 6 on the surface of the block 4 in this way, the ABS braking on the road surface on ice is caused by the interaction between the shallow groove 6 and the dimple 5 constituting the recess. At the time of a slight slip, the snow and snow or water film intervening between the road surface and the tread surface is wrapped by the shallow groove 6 and guided to the dimple 5 side, and the ice and snow clogged in the dimple 5 are externally applied by the centrifugal force accompanying the rotation of the tire. To be discharged. As a result, a new tread surface to which no snow is attached comes into contact with the road surface on ice again, so that the ABS braking performance on the ice road surface can be improved.

  The shallow grooves 6 that connect the dimples 5 to each other are linear, and may be arranged to be inclined with respect to the tire circumferential direction so as to be radial from the dimples 5. Thereby, the shallow groove 6 can efficiently wrap the snow and water film interposed between the road surface and the tread surface and can smoothly move the snow and snow film toward the dimple 5.

  According to the knowledge of the present inventor, the effect of improving the braking performance on ice obtained by forming only the dimples 5 on the surface of the block 4 is mainly that the dimples 5 envelop the ice and snow interposed between the tread and the ice road surface. This is obtained by discharging to the outside due to the centrifugal force accompanying the rotation of the tire. As an effect of improving the ABS braking performance on the road surface on ice, the tire which does not form a recess on the surface of the block 4 is assumed to be 100. Furthermore, it has been found that the maximum is about 103.

  On the other hand, the effect of improving the braking performance on ice obtained by forming only the shallow groove 6 on the surface of the block 4 is mainly due to the fact that ice snow and water film interposed between the tread and the ice road surface are moved outside along the shallow groove 6. It has been found that the effect of improving the ABS braking performance on the road surface on ice is about 104 when the tire that does not form a recess on the surface of the block 4 is defined as 100.

  On the other hand, in the pneumatic tire of the present invention, as shown in the following examples, the effect of improving the ABS braking performance on the road surface on ice is due to the synergistic effect of the shallow groove 6 and the dimple 5 constituting the concave portion. It was confirmed that the tire was improved to about 110 when the number of tires having no recesses on the surface was 100.

  A conventional tire in which the tire size is 195 / 65R15 and the tread pattern is the same as in FIG. 1 and no recess is formed on the surface of each block (conventional example 1), and a conventional tire in which only the dimples shown in Table 1 are formed. (Conventional Example 2), a conventional tire (conventional example 3) in which only the connecting grooves shown in Table 1 are formed, and a tire of the present invention in which dimples and connecting grooves are made different as shown in Table 1 (Examples 1 to 11). ) And comparative tires (Comparative Examples 1 to 8). The number of dimples formed on the surface of each block was common to 21 pieces.

These 22 types of tires are fitted to a rim (15 × 6 1 / 2J), filled with air pressure of 200 kPa, mounted on a domestic FR (2500 cc) vehicle, and the braking performance on ice is evaluated by the following method. The results are shown in Table 1 together with an index display with the conventional example 1 as 100. The larger the value, the better.
[Evaluation of braking performance on ice]
The braking distance was measured by lock braking at a braking speed of 40 km / h on the road surface on ice, and evaluated based on the result.

  As a result, it can be seen that the tire of the present invention is superior in ABS braking performance on an icy road surface as compared with Conventional Example 1.

It is a partial top view which shows an example of the tread surface of the pneumatic tire which consists of embodiment of this invention. It is an enlarged plan view of the block in the pneumatic tire of FIG. It is XX arrow sectional drawing of FIG.

Explanation of symbols

1 Tread surface 2 Vertical groove 3 Horizontal groove 4 Block 5 Dimple 6 Shallow groove

Claims (2)

In a pneumatic tire in which a large number of blocks are formed on the tread surface by vertical grooves extending in the tire circumferential direction and a plurality of horizontal grooves intersecting the vertical grooves,
A large number of dimples having a depth of 0.1 to 0.5 mm and a surface area of 0.7 to 15 mm ² are distributed on the surface of the block, and the depth and width of the dimples are 0.1 and 0.1 respectively. A pneumatic tire connected by three or more shallow grooves of ~ 0.5 mm. The pneumatic tire according to claim 1, wherein the shallow groove is linear and is inclined with respect to the tire circumferential direction.

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