JP2007314137A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently ensure a grounding area of a block 11 while enhancing performance on ice and snow, and to improve brake performance on a dry road surface or a wed road surface. <P>SOLUTION: On the blocks 11 in at least one block line 9 of a plurality of the block lines 9, a plurality of sipes 13 extending in a tire width direction W is formed at intervals in a tire circumferential direction C. The plurality of sipes 13 have intermittent portions 13d divided at least at one part, and the intermittent portions 13d of the sipes 13 adjacent to each other in the tire circumferential direction C are deviated in the tire width direction W. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pneumatic tire such as a studless tire using a block pattern.

  In order to improve the performance on ice and snow in a pneumatic tire such as a studless tire, a block pattern is used as shown in Patent Document 1 and Patent Document 2, and the pneumatic tire according to this prior art will be described. It becomes as follows.

That is, a plurality of main grooves extending in the tire circumferential direction are provided in the tread portion of the pneumatic tire. Further, the tread portion is provided with a plurality of lug grooves extending in the tire width direction so as to intersect the main groove. A plurality of block rows are partitioned along the tire width direction by a plurality of main grooves and a plurality of lug grooves, and each block row is composed of a plurality of blocks arranged in the tire circumferential direction. ing. Further, each block is formed with a plurality of sipes extending in the tire width direction so as to be disposed in the tire circumferential direction.
Japanese Patent Laid-Open No. 10-24707 Japanese Patent Laid-Open No. 11-5415

  By the way, in order to improve the performance on ice and snow, it is necessary to increase the number of sipes and to fully exhibit the edge effect (scratch effect) by the sipes. On the other hand, when the number of sipes is increased, the rigidity of the block (the rigidity in the front-rear direction of the block) decreases, and the collapse of the block increases. Therefore, the braking performance on the dry road surface or the wet road surface is reduced by reducing the contact area of the block.

  That is, the conventional pneumatic tire described above has a problem that it is extremely difficult to improve the braking performance on the dry road surface or the wet road surface while improving the performance on ice and snow.

  Accordingly, an object of the present invention is to provide a novel pneumatic tire that can suppress a decrease in rigidity in the front-rear direction of a block even if the number of sipes is increased in order to solve the above-described problems. To do.

  A first feature of the present invention (a feature of the invention described in claim 1) is that a plurality of main grooves provided in the tread portion and extending in the tire circumferential direction, and the tread portion intersect the main grooves. A plurality of lug grooves provided in the tire width direction, and a plurality of blocks partitioned along the tire width direction by the plurality of main grooves and the plurality of lug grooves and arranged in the tire circumferential direction. In a pneumatic tire provided with a plurality of block rows each configured, a plurality of sipes extending in the tire width direction are provided in the tire circumferential direction on the blocks in at least one block row of the plurality of block rows. Each of the plurality of sipes is formed at an interval, and each of the plurality of sipes is divided into at least one portion, and the intermittent portions of the sipes adjacent to each other in the tire circumferential direction are tied. It is that they are displaced in the width direction.

  According to the first feature, each of the plurality of sipes has the intermittent portion in at least one place, and the intermittent portions of the sipes adjacent in the tire circumferential direction are displaced in the tire width direction. Therefore, it is possible to disperse locally highly rigid portions in the block. Thereby, even if it increases the number of the said sipes, the fall of the rigidity of the said block can be suppressed.

  The second feature of the present invention (the feature of the invention described in claim 2) is that, in addition to the first feature, the length of the intermittent portion in the tire width direction is 1.0 mm or more and 5.0 mm or less. It is that.

  In addition, the length of the intermittent portion in the tire width direction is set to 1.0 mm or more because if the length of the intermittent portion is less than 1.0 mm, a locally sufficiently rigid portion in the block is provided. This is because it cannot be dispersed and the decrease in rigidity of the block is not sufficiently suppressed. The length of the intermittent portion in the tire width direction is set to 5.0 mm or less because when the length of the intermittent portion in the tire width direction exceeds 5.0 mm, the edge effect by the sipe is more fully exhibited. This is because the performance on ice and snow cannot be further improved.

  According to a third feature of the present invention (a feature of the invention described in claim 3), in addition to the first feature or the second feature, the intermittent portions of the plurality of sipes are staggered along the tire circumferential direction. It is arranged in a shape.

  According to the third feature, since the intermittent portions of the plurality of sipes are arranged in a staggered manner along the tire circumferential direction, locally rigid portions can be dispersed substantially uniformly in the block. it can.

  According to a fourth feature of the present invention (a feature of the invention described in claim 4), in addition to any one of the first to third features, the at least one block row has a tire width direction. The outermost block row (shoulder block row).

  Here, the reason why the at least one block row is the shoulder block row is that the shoulder block contributes greatly to the braking performance on the dry road surface or the wet road surface.

  According to the invention described in any one of claims 1 to 4, even if the number of the sipes is increased, a decrease in rigidity of the block can be suppressed, so that the edge effect due to the sipes is sufficient. It is possible to improve the braking performance on the dry road surface or the wet road surface by ensuring sufficient contact area of the block while improving the performance on ice and snow.

  An embodiment of the present invention will be described with reference to FIGS. 1 to 3.

  Here, FIG. 1A is a plan view of a block according to the embodiment of the present invention, FIG. 1B is a side view of the block according to the embodiment of the present invention, and FIGS. FIG. 3 is a plan view of a part of a tread portion in a pneumatic tire according to an embodiment of the present invention. FIG. 3 is a plan view of a block according to another aspect of the embodiment of the present invention.

  As shown in FIG. 3, the pneumatic tire 1 according to the embodiment of the present invention is a studless tire using a block pattern, and the tread portion 3 of the pneumatic tire 1 extends in the tire circumferential direction C. A plurality of main grooves 5 are provided. The tread portion 3 is provided with a plurality of lug grooves 7 extending in the tire width direction W so as to intersect the main groove 5.

  A plurality of block rows 9 are partitioned along the tire width direction W by the plurality of main grooves 5 and the plurality of lug grooves 7, and each block row 9 is a plurality of rows arranged in the tire circumferential direction C. Each block 11. Here, in the embodiment of the present invention, the plurality of block rows 9 include a pair of block rows (center block row) 9A on the tire width direction W center side and a pair of block rows on the outermost side in the tire width direction W. (Shoulder block row) 9B. The shoulder block row 9B has a large contribution to the braking performance on the dry road surface or the wet road surface.

  The specific configuration of the block 11 in each block row 9 is as follows.

  That is, as shown in FIG. 1A, a plurality of sipes 13 extending in a zigzag shape in the tire width direction W are formed in the block 11 at intervals in the tire circumferential direction C. The sipe 13 extending in the tire width direction W refers to the sipe 13 extending in a direction within a range of ± 20 degrees with respect to the tire width direction W.

  Here, although the direction (implantation direction) of the plurality of sipes 13 is alternately different along the tire circumferential direction C, it may be the same. Further, instead of the plurality of sipes 13 extending in a zigzag shape in the tire width direction W, as shown in FIG. 2A, the sipe 13 may be linearly extended in the tire width direction W, or as shown in FIG. In addition, it may extend in a wavy shape in the tire width direction W. Further, as shown in FIG. 1B, the sipe 13 is not bent with respect to the depth direction (left-right direction in FIG. 1B), but may be bent with respect to the depth direction. .

  As shown in FIG. 1A and FIG. 2A and FIG. 2B, the plurality of sipes 13 each have an intermittent portion (divided portion) 13d divided at at least one location. The intermittent portions 13d of the plurality of sipes 13 are arranged in a zigzag pattern along the tire circumferential direction C, and the intermittent portions 13d between the sipes 13 adjacent to each other in the tire circumferential direction C are arranged in the tire width direction W. Misaligned. In particular, in the embodiment of the present invention, the length of the intermittent portion 13d in the tire width direction W is 1.0 mm or more and 5.0 mm or less.

  Then, the effect | action and effect of embodiment of this invention are demonstrated.

  Since the plurality of sipes 13 each have at least one intermittent portion 13d, and the intermittent portions 13d between the sipes 13 adjacent in the tire circumferential direction C are displaced in the tire width direction W, the block 11 It is possible to disperse locally high rigidity portions in. In particular, since the intermittent portions 13d of the plurality of sipes 13 are arranged in a zigzag pattern along the tire circumferential direction C, locally rigid portions in the block 11 can be dispersed substantially uniformly. Thereby, even if the number of the sipes 13 is increased, a decrease in the rigidity of the block 11 (the rigidity in the front-rear direction of the block 11) can be suppressed.

  As described above, the length of the intermittent portion 13d in the tire width direction W is set to 1.0 mm or more because the length of the intermittent portion 13d is less than 1.0 mm locally enough in the block 11. This is because it is impossible to disperse the portion having high rigidity, and the decrease in rigidity of the block 11 is not sufficiently suppressed. Further, the length of the intermittent portion 13d in the tire width direction W is set to 5.0 mm or less because when the length of the intermittent portion 13d in the tire width direction W exceeds 5.0 mm, the edge effect by the sipe 13 is more sufficiently achieved. This is because the performance on ice and snow cannot be further improved.

  Therefore, according to the embodiment of the present invention, even if the number of sipes 13 is increased, the decrease in rigidity in the front-rear direction of the block 11 can be suppressed. While improving, the sufficient contact area of the block 11 can be ensured, and the braking performance on the dry road surface or the wet road surface can be improved.

  The present invention is not limited to the description of the above-described embodiment. For example, a plurality of sipes 13 having intermittent portions 13d in the blocks 11 in each block row 9 are spaced in the tire circumferential direction C. The plurality of sipes 13 having the intermittent portions 13d only on the blocks 11 in the shoulder block row 9B may be formed at intervals in the tire circumferential direction C. It is possible to implement in the mode. Further, the scope of rights encompassed by the present invention is not limited to these embodiments.

  Examples of the present invention will be described.

  First comparative example using the pneumatic tire 1 according to the embodiment shown in FIGS. 1 (a), 1 (b) and 3 as an invention, and using the block 15 shown in FIGS. 4 (a) and 4 (b) instead of the block 11 The pneumatic tire according to the second comparative example using the block 17 shown in FIGS. 5 (a) and 5 (b) instead of the block 11 as the comparative product 1, and the tire size 185 / A prototype was made under 70R14. The block 15 shown in FIGS. 4A and 4B differs from the block 11 only in that the sipe 13 does not have the intermittent portion 13d. The block 17 shown in FIGS. It differs from the block 11 only in that the intermittent portion 13d between the sipes 13 adjacent in the direction C is not displaced in the tire width direction W.

  Then, the on-ice acceleration performance test and the dry brake performance test are performed on the invention product, the comparative product 1 and the comparative product 2, respectively. Based on the test results, the on-ice acceleration performance and the dry brake performance (brake performance on the dry road surface) I decided to evaluate.

(i) On-ice acceleration performance test In the on-ice acceleration performance test, the vehicle is accelerated to 30 km / h on the test course on the ice board road surface with the invention product, comparative product 1 and comparative product 2 mounted on the vehicle. Measure the time required. Then, as a result of the on-ice acceleration performance test, the reciprocals of the measured times are summarized by index display as shown in Table 1 below. In addition, it has shown that the acceleration performance on ice is so high that the index | exponent of ice acceleration performance evaluation is large.

(ii) Dry brake performance test In the dry brake performance test, it is necessary to stop from 80 km / h on the dry road test course with the inventive product, comparative product 1 and comparative product 2 mounted on the vehicle. The measured time is measured. Then, as a result of the dry brake performance test, the reciprocal of the measured time is summarized as an index display as shown in Table 1 below. In addition, it shows that dry brake performance is so high that the index | index of dry brake performance evaluation is large.

  That is, as shown in Table 1, the invention product improves the dry brake performance as compared with the comparative product 1 and the comparative product 2 while maintaining the acceleration performance on ice and snow comparable to the comparative product 1 and the comparative product 2. Was confirmed.

FIG. 1A is a plan view of a block according to the embodiment of the present invention, and FIG. 1B is a side view of the block according to the embodiment of the present invention. It is a top view of the block concerning another mode of the embodiment of the present invention. It is a plane development view of a part of a tread part in a pneumatic tire concerning an embodiment of the present invention. FIG. 4A is a plan view of a block according to the first comparative example, and FIG. 4B is a side view of the block according to the first comparative example. FIG. 5A is a plan view of a block according to the second comparative example, and FIG. 5B is a side view of the block according to the second comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 3 Tread part 5 Main groove 7 Lug groove 9 Block row 11 Block 13 Sipe 13d Intermittent part

Claims (4)

A plurality of main grooves provided in the tread portion and extending in the tire circumferential direction, a plurality of lug grooves provided in the tread portion so as to intersect the main groove and extending in the tire width direction, and the plurality of grooves In a pneumatic tire provided with a plurality of block rows each composed of a plurality of blocks partitioned along the tire width direction and arranged in the tire circumferential direction by the main groove and the plurality of lug grooves,
A plurality of sipes extending in the tire width direction are formed at intervals in the tire circumferential direction on the blocks in at least one block row of the plurality of block rows, and the plurality of sipes are at least in one place. A pneumatic tire characterized by having divided interrupted portions, wherein the interrupted portions of the sipes adjacent to each other in the tire circumferential direction are displaced in the tire width direction.   2. The pneumatic tire according to claim 1, wherein a length of the intermittent portion in a tire width direction is 1.0 mm or more and 5.0 mm or less.   The pneumatic tire according to claim 1 or 2, wherein the intermittent portions of the plurality of sipes are arranged in a staggered manner along the tire circumferential direction.   The pneumatic tire according to any one of claims 1 to 3, wherein the at least one block row is an outermost block row in the tire width direction.

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