JPH02182503A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To generate additional traction effect to increase running performance on snow road by forming multiple fixing sections, provided with a small wide groove section opening at a buttless surface and a projected section projected from the buttless surface, on a shoulder block. CONSTITUTION:Multiple fixing sections 7 are formed in a shoulder block formed on the tread section of a pneumatic tire by projecting them from a buttless section 3. A small wide groove section 10, recessed by a distance of 11 form a tread edge T to the inner axial direction of the tire, extending outwards from the start point 9 on the shoulder block, and opening at the buttless section 3 at the other end, is provided on each fixing section 7. A projected section 11, having an upper surface 11A connected to the bottom surface 10A of the small wide groove section 10 and extending projectedly by a specified distance of 12 from the buttless surface 3 to the axial direction of the tire, is also provided. Each fixing section 7 is contacted with the wall surface of a wheel-mark on a read covered with pressed snow to obtain good traction effect.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pneumatic tire with improved traction performance on snowy roads.

[Conventional technology]

Conventionally, in snow tires used for driving on snowy roads, blocks of various shapes, siping, etc. are arranged in the tread part, and the amount of penetration of the blocks into the snow surface and the scraping of the snow surface by the block edges and siping edges are determined. ,
By increasing the scratching effect, the performance of troughsilane, such as braking performance, starting performance, and climbing performance, is improved.

[Problem to be solved by the invention]

However, all of these conventional methods are improvement means related to the tread pattern, and they have not yet achieved a fully satisfactory effect, and further improvements have been desired in recent years.

The present invention was developed by focusing on the fact that when driving on a snow-covered road, especially on a snow-compacted road, the ear buff-less portion comes into contact with the wall surface of the ruts formed on the snow-compacted road, and a locking portion is formed on the shoulder block. Based on this principle, the purpose of the present invention is to provide a pneumatic tire that contributes a new traction effect to the buttress portion and can significantly improve the traction performance of the tire as a whole.

[Means for Solving the Problem] In order to achieve the above object, the pneumatic tire of the present invention has the following features:
By recessing the tread portion with lateral grooves that open at the buttress surface that connects to the tread edge, shoulder blocks are formed between the lateral grooves and are arranged circumferentially along the tread edge, and the trend edge is aligned in the axial direction of the tire. A plurality of locking portions each having a narrow groove portion opening at the buttress surface starting from the upper surface of the inner shoulder block, and a raised portion having an upper surface continuous to the bottom surface of the groove portion and protruding from the buttress surface; It is formed in the shoulder block.

Further, the distance from the tire equator of the starting point of the narrow groove portion may be 0.460 times or more and 0°4975 times or less of the tread width WT, which is the length in the tire axial direction between the tread edges. Preferably, the ridge has a protruding portion that protrudes from the buttress surface at a radial location spaced radially inwardly from the upper surface of the shoulder block by 5% of the transverse groove depth.

[Effect]

In the pneumatic tire constructed in this way, on a rutted road surface, the raised portion provided on the locking portion engages with the rutted wall surface and produces a traction effect due to the scraping effect and scratching effect. In addition, the narrow groove part of the locking part is suitable for smooth road surfaces,
It grips both the rutted road surfaces and works with the raised portions to further improve traction performance.

By regulating the radial position of the protruding portion, that is, the radial protruding area of the protrusion and the starting point position of the narrow groove, uneven wear can be suppressed and traction performance can be effectively enhanced from the initial stage to the final stage of wear.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 illustrates a tread pattern of a pneumatic tire 1 according to the present invention.
, G2, G2 (generally referred to as the main groove G), and a lateral groove that is open at one end on the buttress surface 3 connected to the tread uT and extends across the main groove C. The tread portion 2 includes a center block row UC consisting of center blocks BC spaced apart on the tire equator, and shoulder blocks consisting of shoulder blocks BS spaced apart along the tread edge T. The intermediate block row υM is formed by juxtaposing intermediate blocks BM- between the row US and the center block row UC and the shoulder block row US.

Each of the block rows UC, UM, US includes 25 to 60 blocks BCSBM, BS in the tire circumferential direction, and the total area SA of the upper surfaces of the blocks BC, BM, BS,
The ratio SA/S to the total surface area S of the tread portion 2 is 0.45.
-0.75, more preferably 0.5-0.7. When the ratio SA/S is greater than 0°75,
Although it has excellent abrasion resistance, it reduces the engagement force with lightning and ice, degrading performance on snow and ice.If it is smaller than 0.45, the ground contact area becomes too small, reducing abrasion resistance.

Further, the upper edge and side edge of each block BC, BM, BS are formed with edges, respectively, and the front and rear end faces S1 facing the lateral groove K
By providing a rectangular uneven portion on the end surface s2 on the side facing the main groove G, the engagement force with snow and ice and the scratching effect are uniformed.

Further, a plurality of retaining portions 7--, which are five in this example, are formed on the shoulder block BS so as to protrude from the buttress surface 3.

The locking portion 7 has a starting point 9 at a position on the upper surface of the shield block BS that is a distance 611 inward in the axial direction of the tire from the tread edge T.
It has a narrow groove part 1o which extends outward and opens at the other end at the buttress surface 3, and an upper surface 11A that is continuous with the bottom surface 10A of the narrow groove part 10, and projects a distance f2 from the buttress surface 3 in the tire axial direction. The ridge 11 extends and is aligned with the buttress surface 3 through an end surface 11B that is substantially parallel to the buttress surface 3.

In addition, the bottom surface 10A of the narrow groove 10 and the top surface 11A of the raised portion 11 form the same slope with an inclination angle θ of about 40 degrees in this example, and the upper edge 10a of the narrow groove 10 and the upper surface of the raised portion 11 Both edges 11a are formed with edges.

Therefore, the locking part 7 formed in this way improves traction performance by scraping off the snow caught in the narrow groove part 10 by the upper edge 10a, and at the same time improves the traction performance in the traveling direction of the raised part 11 protruding from the buttress surface 3. A new trough silane action can be caused by the scratching and scraping effect on the wall surface of the ruts formed on the snow compacted road surface by the facing side surface 11c.

The raised portion 11 is located at a radial position W,
It is preferable to have a protruding portion 12 protruding from the buttress surface 3 on the inner side of the buttress surface 3, whereby the traction effect can be produced from the initial stage of tire wear to su, II. In order to effectively exhibit such an effect, the distance from the tire equator CO to the starting point 9 must be at least 0.46 times the tread width WT, which is the axial length of the tire between the tread edges T. and 0.4975 times or less, and generally the distance I! from the tread edge T! , 1 is preferably 1.5w or more and 8 stores or less.

Further, the distance 12 from the tread edge T to the upper edge 11a of the raised portion 11 is 0.01 times or more the tread width WT.

This was derived from various actual vehicle tests conducted by the inventor, and examples of the test results are shown in FIGS. 5 to 7.

The test was an actual vehicle driving test conducted under the conditions shown in Table 1 using a prototype tire with a tread pattern shown in Fig. 1 and a tire size of 10.0OR20 mounted on a vehicle (2-D-4). FIG. 5 shows the relationship between the distance QL and braking performance on a flat snow-filled road surface, FIG. 6 shows the relationship between the distance 12 and braking performance on a rutted snow-filled road surface, and FIG. The figure shows the relationship between the distance and the heel-and-toe wear 1 (after 30,000 miles) on both sides of the narrow groove portion 10, respectively.

As shown in Figure 5.7, the distance is 0°497
If it exceeds 5 WT, traction performance will be impaired and braking performance will be reduced, and if it is less than 0.46 WT, heel and toe wear will increase, making it unsuitable for actual use.

Furthermore, if the distance 22 is less than 0.01 WT, the braking performance will be reduced as shown in FIG. Further, FIGS. 8 and 9 show other embodiments of the locking portion 7. In FIG. 8, the locking portion 7 includes a raised portion 11 that is wider than the narrow groove portion 1o. In addition, in FIG. 9, the locking part 7 has a bottom surface 10A on the outside of the narrow groove part 10 having a bottom surface 10A parallel to the upper surface of the shoulder prong BS.
A raised portion 11 is provided having an upper surface 11A that slopes and intersects with the upper surface 11A.

〔Effect of the invention〕

Like a ridge, the pneumatic tire of the present invention is provided with a locking portion in the sigolder block that includes a narrow groove portion that opens on the buttress surface and a raised portion that protrudes from the buttress surface, so that it can run on a compacted snow road surface. At this time, when the locking portion comes into contact with the rut wall surface formed on the road surface, a new traction effect can be generated, and the driving performance on snowy roads can be greatly improved.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an embodiment of the tread pattern of the present invention, Fig. 2 is a sectional view thereof, Fig. 3 is an enlarged perspective view showing the shoulder block, and Fig. 4 is an enlarged view of the locking part. Figure 5 is a diagram showing the relationship between distance and braking performance, Figure 6 is a diagram showing the relationship between distance 12 and braking performance, and Figure 7 is a diagram showing the relationship between distance and heel-and-toe. Diagrams showing the relationship of wear, and FIGS. 8 and 9 are perspective views showing other embodiments of the locking portion. 10A.~Bottom surface, 1 12--Protruding part.

Claims (1)

[Scope of Claims] 1. By recessing the tread portion with lateral grooves that open at the buttress surface that connects to the tread edge, shoulder blocks are formed circumferentially along the tread edge between the lateral grooves, and The tread edge has a narrow groove portion opening at the buttress surface starting from the upper surface of the shoulder block on the inner side of the tire in the axial direction of the tread edge, and a raised portion having an upper surface continuous to the bottom surface of the groove portion and protruding from the buttress surface. A pneumatic tire in which a plurality of locking portions are formed on the shoulder block. 2. The starting point of the narrow groove has a distance L from the tire equator that is 0.460 times or more and 0.4975 times or less of the tread width WT, which is the length in the tire axial direction between the tread edges, and is raised. 2. The pneumatic tire according to claim 1, wherein the portion has a protruding portion protruding from the buttress surface at a radial position spaced radially inward from the upper surface of the shoulder block by a distance of 15% of the depth of the lateral groove.