JP2010254154A - Tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire further enhancing on-snow/ice performance while maintaining rigidity of a block. <P>SOLUTION: The pneumatic tire 1 includes a block 20 divided by a circumferential groove and a lateral groove, a sipe 30 extending in a tread width direction W in a zig-zag form is formed on the block 20, and both ends of the sipe 30 are communicated with the circumferential groove at both ends in the tread width direction W of the block 20 respectively. The block 20 includes a pair of sidewall surfaces 52, 54 arranged in a tire circumferential direction and forming the sipe 30; and a pair of bottom-up parts 40 extending from a bottom of the sidewall surface 52 to an outer side in a tire radial direction along a tire radial direction D at both sides along the tread width direction W of the block 20. The bottom-up part 40 is positioned so as to be spaced from both sides in the tread width direction W of the sipe 30 to a central side of the block 20 in the tread width direction W by a predetermined distance, and is continued from one sidewall surface 52 forming the sipe 30 to the other sidewall surface 54. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes a block defined by a circumferential groove extending along the tire circumferential direction and a lateral groove extending along the tread width direction, and a sipe extending zigzag along the tread width direction is formed in the block. In particular, the present invention relates to a tire in which the rigidity of the block is further improved while ensuring the performance on snow and ice.

  Conventionally, tires suitable for running on icy and snowy roads have a zigzag-like shape extending along the tread width direction in a tread block in order to improve braking force and traction (hereinafter referred to as snow and ice performance) on icy and snowy roads. A method of forming a sipe or increasing the depth of a sipe is widely used.

  In such a sipe-formed tire, in order to improve the rigidity of the block, a sipe having a bottom raised portion extending from the bottom forming the sipe bottom in the tire radial direction and having a shallow part of the groove depth is provided. A forming method is widely known (for example, Patent Document 1). In particular, it is known that a method in which the above-described raised portions are provided at both ends of the block in the tread width direction and the groove depth at both ends of the sipe is shallow is effective for improving the rigidity of the block.

Japanese Patent Laying-Open No. 2005-67274 (page 5-6, FIG. 3)

  However, the conventional tire described above has the following problems. In other words, the rigidity of the block can be improved, but at both ends of the sipe along the tread width direction, the sipe does not open along the tire circumferential direction, and the edge effect (digging frictional force) acting on the edge of the sipe or tread pattern cannot be obtained. In addition, there was a problem that the performance on snow and ice, specifically, the braking force and traction on the snowy road decreased.

  Therefore, an object of the present invention is to provide a tire that further improves the performance on snow and ice while maintaining the rigidity of the block.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is that a circumferential groove (circumferential groove 10) extending along the tire circumferential direction (tire circumferential direction R) and a lateral groove extending along the tread width direction (tread width direction W) ( A tire (pneumatic tire 1) having a block (block 20) partitioned by a lateral groove 12) and having sipes (sipe 30) extending in a zigzag shape along the tread width direction (tread width direction W). And both ends of the sipe communicate with the circumferential grooves at both ends in the tread width direction of the block, and the blocks are arranged in the tire circumferential direction, and a pair of side wall surfaces (side wall surfaces 50) forming the sipe, A pair of raised bottom portions (bottom raised portions 40) extending outward in the tire radial direction along the tire radial direction (tire radial direction D) from the bottom of the side wall surface on both sides along the tread width direction of the block; The bottom raised part is located at a predetermined distance from the both ends of the sipe in the tread width direction at a center of the block in the tread width direction, and forms the sipe from one side wall surface (side wall surface 52) that forms the sipe. The gist is that it is connected to the other side wall surface (side wall surface 54).

  According to such a tire, the bottom raising part located apart from both ends of the block in the tread width direction by a predetermined distance is provided. The groove depth of the sipe in the region where the bottom raised portion is formed becomes shallower than the other sipe regions, and the opening of the sipe is suppressed. That is, since the opening of the sipe located at a predetermined distance from both ends of the block where the rigidity is lowest due to the opening of the sipe is suppressed, the rigidity of the entire block is improved.

  Moreover, since the bottom raising part is not formed in the both ends of the sipe in a tread width direction, the groove depth of the both ends of the sipe in a tread width direction is ensured. For this reason, at both ends of the sipe along the tread width direction, the sipe opens along the tire circumferential direction, and an edge effect (digging frictional force) acting on the edge of the sipe or the tread pattern can be obtained.

  Therefore, according to such a tire, the rigidity of the block can be further improved while maintaining the performance on snow and ice.

  The second feature of the present invention relates to the first feature of the present invention, wherein the width of the bottom raised portion (width W1) in the tread width direction is 10% of the block width (width W2) in the tread width direction. That is the summary.

  A third feature of the present invention relates to the first or second feature of the present invention, and is the depth (depth) from the surface of the tread (tread 22) to the bottom raised portion in the sipe depth direction (tire radial direction D). The gist of D1) is 20% or more and 70% or less with respect to the depth (depth D2) from the surface of the tread to the bottom of the sipe in the sipe depth direction.

  A fourth feature of the present invention relates to any one of the first to third features of the present invention, wherein the predetermined distance is 10% or more and 30% or less with respect to the block width in the tread width direction. Is the gist.

  According to the characteristics of the present invention, it is possible to provide a tire that further improves the performance on snow and ice while maintaining the rigidity of the block.

It is an expanded view of the tread which comprises the pneumatic tire concerning the embodiment of the present invention. It is a partial exploded perspective view of a block which constitutes a pneumatic tire concerning an embodiment of the present invention. It is sectional drawing of the block which comprises the pneumatic tire which concerns on embodiment of this invention. It is sectional drawing of the block which comprises the pneumatic tire which concerns on other embodiment of this invention.

  Next, an embodiment of a pneumatic tire according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[Embodiment]
In the present embodiment, (1) a configuration of a pneumatic tire, (2) a detailed configuration of a block, (3) comparative evaluation, (4) actions and effects, and (5) other embodiments will be described.

(1) Configuration of Pneumatic Tire FIG. 1 is a development view of a tread constituting the pneumatic tire 1 according to the embodiment of the present invention. The pneumatic tire 1 is a so-called studless tire suitable for traveling on icy and snowy roads. Each part formed in the tread in the pneumatic tire 1 will be further described.

  The pneumatic tire 1 includes a block 20 defined by a circumferential groove 10 extending along the tire circumferential direction R and a lateral groove 12 extending along the tread width direction W.

  In each block 20, a sipe 30 extending in a zigzag shape along the tread width direction W is formed. Both ends of the sipe 30 in the tread width direction W communicate with the circumferential groove 10 at both ends in the tread width direction W of the block 20, respectively.

(2) Detailed configuration of block The detailed configuration of the block will be described. Will be described with reference to FIGS. FIG. 2 is a partially exploded perspective view of the block 20 constituting the pneumatic tire 1 according to the embodiment of the present invention. 3 is a cross-sectional view of the block 20 constituting the pneumatic tire 1 according to the embodiment of the present invention. As shown in FIGS. 2 and 3, the block 20 is aligned in the tire circumferential direction R to form a sipe 30. A pair of side wall surfaces 50 and a pair of raised portions 40 extending outward in the tire radial direction along the tire radial direction D from the bottom of the side wall surface 50 on both sides along the tread width direction W of the block 20 are provided. Specifically, the side wall surface 50 includes a side wall surface 52 and a side wall surface 54 facing the side wall surface 52. That is, the sipe 30 is formed by one side wall surface 52, the other side wall surface 54, and the pair of bottom raised portions 40.

  The bottom raised portion 40 is located at a predetermined distance L1 away from both ends of the sipe 30 in the tread width direction W at the center side of the block 20 in the tread width direction W, and from one side wall surface 52 forming the sipe 30 to the sipe 30. Is connected to the other side wall surface 54.

  Specifically, as shown in FIG. 3, the end portion of the bottom raising portion 40 on the outer side in the tread width direction is located away from the end portion of the sipe 30 in the tread width direction W by a predetermined distance L1. The predetermined distance L1 is 10% or more and 30% or less with respect to the width W3 of the block 20 in the tread width direction W. More preferably, the predetermined distance L1 is 10% or more and 25% or less with respect to the width W3 of the block 20 in the tread width direction W.

  The width W1 of one bottom raised portion 40 in the tread width direction W is 10% or more with respect to the width W3 of the block 20 in the tread width direction W. Similarly, the width W2 of the other raised portion 40 in the tread width direction W is 10% or more with respect to the width W3 of the block 20 in the tread width direction W.

  The depth D1 from the surface of the tread 22 in the depth direction of the sipe 30 (that is, the tire radial direction D) to the bottom raised portion 40 is from the surface of the tread 22 in the depth direction of the sipe 30 (that is, the tire radial direction D). The depth D2 to the bottom of the sipe 30 is 20% or more and 70% or less. The depth D1 from the surface of the tread 22 to the bottom raised portion 40 indicates the distance from the end portion of the bottom raised portion 40 on the outer side in the tire radial direction to the surface of the tread 22 along the tire radial direction D. In the present embodiment, the depth D1 is set to the same depth for the pair of bottom raised portions 40 located on both sides in the tread width direction W.

(3) Comparative Evaluation Next, in order to further clarify the effects of the present invention, comparative evaluation performed using pneumatic tires according to the following comparative examples and examples will be described. Specifically, (1) an evaluation method and (2) an evaluation result will be described. In addition, this invention is not limited at all by these examples.

(1) Evaluation method Using six types of pneumatic tires, the driving force, braking performance, and turning performance on an icy and snowy road surface were evaluated. Data on pneumatic tires were measured under the following conditions.

・ Tire size: 205 / 55R16 LM30Z
・ Rim wheel size: width 6.5J x rim diameter 16
・ Load condition: Vehicle weight + 1 test driver ・ Internal pressure: 220 kPa
・ Evaluation vehicle: FF sedan (2000 cc displacement)
Each pneumatic tire has a different arrangement of the raised bottom portion. Hereinafter, the different points will be described in detail.

  The pneumatic tire according to the example has the same configuration as the pneumatic tire 1 according to the embodiment.

  The pneumatic tire according to the comparative example is different from the pneumatic tire according to the embodiment in that the pneumatic tire according to the comparative example includes bottom raised portions that are not provided with a predetermined distance at both ends of the sipe along the tread width direction.

(1.1) Evaluation of driving force The time required to start at 0 km / h on a snowy and snowy road surface and reach the reference speed was measured.

(1.2) Evaluation of braking performance With a vehicle equipped with the pneumatic tire described above, the braking distance from 30 km / h per hour was measured on an icy and snowy road surface.

(1.3) Evaluation of turning performance On ice and snowy road surfaces, a road surface with a predetermined radius was circulated at a high speed, and the time required to make one turn was calculated.

  The evaluation results of the driving force, the braking performance, and the turning performance are displayed as a contrast index when the evaluation result of the pneumatic tire according to the comparative example, which is a conventional pneumatic tire, is 100. An evaluation result shows that it has the outstanding performance, so that a large numerical value is shown.

(2) Evaluation result The evaluation result of each pneumatic tire will be described with reference to Table 1.

  In comparison with the pneumatic tire of the comparative example, the pneumatic tire of the example improved all the driving power, braking performance, and turning performance.

(4) Actions / Effects As described above, according to the present embodiment, the pneumatic tire 1 includes the bottom raising portion 40 that is located a predetermined distance L1 away from both ends of the block 20 in the tread width direction W. The groove depth of the sipe 30 in the region where the bottom raised portion 40 is formed becomes shallower than the region of the other sipe 30, and the opening of the sipe 30 is suppressed. That is, since the opening of the sipe 30 located at a predetermined distance L1 from both ends of the block 20 where the rigidity is lowest due to the opening of the sipe 30 is suppressed, the rigidity of the block 20 as a whole can be maintained.

  Moreover, since the bottom raising part 40 is not formed in the both ends of the sipe 30 in the tread width direction W, the groove depth of the both ends of the sipe 30 in the tread width direction W is ensured. For this reason, at both ends of the sipe 30 along the tread width direction W, the sipe 30 opens along the tire circumferential direction, and the edge effect (digging frictional force) acting on the edge of the sipe 30 or the tread pattern can be improved.

  Therefore, according to such a pneumatic tire 1, the performance on snow and ice can be further improved while maintaining the rigidity of the block.

  In the conventional pneumatic tire, the rigidity of the block can be improved, but at the both ends of the sipe along the tread width direction, the sipe does not open along the tire circumferential direction, so the sipe does not function as an edge and slip occurs. However, it was the region where the temperature rose most in the block.

  In the conventional pneumatic tire, the edge effect is reduced (decrease in the edge effect) at both ends of the sipe by raising the sipe bottom. According to this embodiment, since the sipe 30 opens along the tire circumferential direction at both ends of the sipe 30 along the tread width direction W, the edge effect reduction can be suppressed. That is, since the edge effect (digging frictional force) acting on the edge of the sipe 30 or the tread pattern can be improved, the temperature increase of the pneumatic tire 1 as described above can be suppressed.

  According to the present embodiment, the width (width W1) of the bottom raised portion 40 in the tread width direction W is 10% or more with respect to the width (width W2) of the block 20 in the tread width direction W. For this reason, since the sipe 30 of the area | region where the bottom raising part 40 in the tread width direction W was formed can fully be ensured, and the opening of the sipe 30 is suppressed, the rigidity as the whole block 20 improves further. When the width (width W1) of the bottom raising portion 40 in the tread width direction W is smaller than 10% with respect to the width (width W2) of the block 20 in the tread width direction W, the opening of the sipe 30 is suppressed. However, at both ends of the sipe 30 along the tread width direction W, the opening becomes excessively large, and the rigidity of the block 20 as a whole may not be sufficiently secured.

  According to the present embodiment, the depth D1 from the surface of the tread 22 in the tire radial direction D of the sipe 30 to the raised portion 40 is the depth from the surface of the tread 22 in the tire radial direction D of the sipe 30 to the bottom of the sipe 30. It is 20% or more and 70% or less with respect to D2. For this reason, the opening of the sipe 30 (specifically, the region of the sipe 30 located on the outer side in the tire radial direction of the region where the bottom raised portion 40 is formed) corresponding to the region where the bottom raised portion 40 is formed in the tread width direction W. However, since it is sufficiently suppressed, the rigidity of the entire block 20 is further improved. When the depth D1 is longer than 70% with respect to the depth D2, the opening of the sipe 30 is not suppressed, and the opening becomes excessively large at both ends of the sipe 30 along the tread width direction W. The rigidity of the block 20 as a whole may not be sufficiently secured. Further, when the depth D1 is shorter than 20% with respect to the depth D2, the opening of the sipe 30 is excessively suppressed and the sipe 30 does not function, so the pneumatic tire 1 has the performance on snow and ice. It may not be obtained sufficiently.

  According to the present embodiment, the predetermined distance L1 is 10% or more and 30% or less with respect to the width W3 of the block 20 in the tread width direction W. For this reason, at both ends of the sipe 30 along the tread width direction W, the sipe 30 is surely opened along the tire circumferential direction, and the edge effect (digging frictional force) acting on the edge of the sipe 30 and the tread pattern is reliably improved. it can. In addition, when the predetermined distance L1 is shorter than 10% with respect to the width W3 of the block 20 in the tread width direction W, the sipe 30 extends along the tire circumferential direction at both ends of the sipe 30 along the tread width direction W. Therefore, the pneumatic tire 1 may not be able to obtain sufficient performance on snow and ice. When the predetermined distance L1 is longer than 30% with respect to the width W3 of the block 20 in the tread width direction W, the distance to the other bottom raised portion 40 is too close, and thus the predetermined distance L1 is located between the pair of bottom raised portions 40. The sipe 30 does not open along the tire circumferential direction and does not function as the sipe 30, and the pneumatic tire 1 may not be able to obtain sufficient performance on snow and ice.

(5) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. Should not. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, the embodiment of the present invention can be modified as follows. In the above-described embodiment, the bottom raised portion 40 includes a surface substantially parallel to the surface of the tread 22 in the cross section along the tread width direction W and the tire radial direction D. Further, the bottom raised portion 40 extends linearly along the tire radial direction D. However, the shape of the bottom raised portion 40 is not limited to this, and for example, as shown in FIG. 4, the bottom raised portion 40A may be formed in a convex curve.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

D: tire radial direction, L1: predetermined distance, R: tire circumferential direction, W: tread width direction, W1, W2, W3 ... width, 1 ... pneumatic tire, 10 ... circumferential groove, 12 ... transverse groove, 20 ... block , 22 ... tread, 30 ... sipe, 40, 40A ... bottom raised part, 50, 52, 54 ... side wall surface

Claims (4)

A tire comprising a block defined by a circumferential groove extending along a tire circumferential direction and a lateral groove extending along a tread width direction, and a sipe extending in a zigzag shape along the tread width direction is a tire formed in the block. There,
Both ends of the sipe communicate with the circumferential groove at both ends in the tread width direction of the block,
The block is
A pair of side wall surfaces arranged in the tire circumferential direction and forming the sipe;
A pair of raised portions extending outward in the tire radial direction along the tire radial direction from the bottom of the side wall surface on both sides along the tread width direction of the block;
The bottom raised portion is
The sipe is located at a predetermined distance from both ends of the sipe in the tread width direction at a center of the block in the tread width direction, and continues from one side wall surface forming the sipe to the other side wall surface forming the sipe. tire.   The tire according to claim 1, wherein a width of the raised portion in the tread width direction is 10% or more with respect to a width of the block in the tread width direction. The depth from the surface of the tread to the bottom raised portion in the depth direction of the sipe is:
3. The tire according to claim 1, wherein the tire is 20% or more and 70% or less with respect to a depth from a tread surface to a bottom of the sipe in a depth direction of the sipe.   The tire according to any one of claims 1 to 3, wherein the predetermined distance is 10% or more and 30% or less with respect to the width of the block in the tread width direction.

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