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EP-4357163-B1 - TIRE

EP4357163B1EP 4357163 B1EP4357163 B1EP 4357163B1EP-4357163-B1

Inventors

  • HAYASHI, SHINTARO

Dates

Publication Date
20260506
Application Date
20220311

Claims (3)

  1. A tire (10, 10b) comprising block rows (31, 32) delimited by a pair of circumferential grooves (41 -43, 41B, 43B) extending in a tire circumferential direction (TC), wherein the block rows (31, 32) include a plurality of blocks (100, 200) delimited by a plurality of lateral grooves (61 [61a, 61b], 62 [62a, 62b])extending in a tire width direction (WD), each block (100, 200) of the plurality of blocks (100, 200) is partitioned into a plurality of small blocks (101, 201) by a circumferential sipe (120, 220) extending in the tire circumferential direction (TC) and a plurality of lateral sipes (130, 230) extending in the tire width direction (WD), the circumferential sipe (120, 220) extends along the tire circumferential direction (TC), the plurality of lateral sipes (130, 230) include a first lateral sipe (130a, 230a)and a second lateral sipe (130b, 230b) extending in different directions from each other, the each block (100, 200) included in at least one of the block rows (31, 32) has a triangular shape in a tread plane view, and each small block (101, 201) of the plurality of small blocks (101, 201) included in the each block (100, 200) included in the at least one of the block rows (31, 32) has a triangular shape in the tread plane view.
  2. The tire (10, 10B) according to claim 1, wherein the at least one of the block rows (31, 32), which includes the plurality of blocks (100, 200) each having the triangular shape and including only the plurality of small blocks (101, 201) each having the triangular shape, is provided only on a center portion (CT, CTB) delimited by a pair of circumferential grooves (41-43, 41B) positioned outermost in the tire width direction (WD) disposed on either side of a tire equatorial line (CL).
  3. The tire (10, 10B) according to claim 1 or claim 2, wherein the circumferential sipe (120, 220) has a constant groove width from a tread side to a bottom, and each of the plurality of lateral sipes (130, 230) has a constant groove width from the tread side to a bottom.

Description

TECHNICAL FIELD The present invention relates to a tire that utilizes a tread pattern with blocks having a relatively small ground area are densely disposed. BACKGROUND ART Conventionally, a method of utilizing a tread pattern with blocks having a relatively small ground area are densely disposed is known for a winter tire (hereinafter denoted as "tire") suitable for traveling on an ice and snow road surface (see PTL 1). PTL 2 discloses a pneumatic tire which has blocks which are separated by circumferential grooves extending in the circumferential direction of the tire, and also by lug grooves extending oblique to the circumferential direction of the tire and each having two or more bent sections. PTL 3 discloses a pneumatic tire, with transverse channels formed on the running surface, which has narrow grooves, shallower and wider than the channels, formed at an angle to the transverse direction of the tire and with the density of the narrow grooves increasing from a central region towards a shoulder region. PTL 4 discloses a pneumatic tire that can be suppressed from being unevenly worn and can be improved in on-snow performance. The tread pattern in which such small blocks are densely disposed has a better ground contact characteristics with the ice and snow road surface than blocks of a general size, and therefore can improve traveling performance on the ice and snow road surface (hereinafter denoted as "on-ice performance"). CITATION LIST PATENT LITERATURE [PTL 1] JP 2017-193202 A[PTL 2] WO 2014/061514 A1[PTL 3] DE 10 2005 030566 B4[PTL 4] JP 2021 070332 A SUMMARY OF INVENTION However, further improvement is required for the conventional tire described above. Specifically, it is required to further improve on-ice performance, especially braking performance on snow and ice roads during cornering. Therefore, an object of the present invention is to provide a tire that further improves braking performance on snow and ice roads during cornering when utilizing a tread pattern with blocks having a relatively small ground area are densely disposed. A tire according to the present invention includes block rows delimited by a pair of circumferential grooves extending in a tire circumferential direction. The block rows include a plurality of blocks delimited by a plurality of lateral grooves extending in a tire width direction. Each block of the plurality of blocks is partitioned into a plurality of small blocks by a circumferential sipe extending in the tire circumferential direction and a plurality of lateral sipes extending in the tire width direction. The circumferential sipe extends along the tire circumferential direction. The plurality of lateral sipes include a first lateral sipe and a second lateral sipe extending in different directions from each other. Each block included in at least one of the block rows has a triangular shape in a tread plane view. Each small block of the plurality of small blocks included in the each block included in the at least one of the block rows has a triangular shape in the tread plane view. In the tire with the above configuration, each block included in the block row is partitioned into the plurality of small blocks by the circumferential sipe extending parallel to the tire circumferential direction, and the plurality of lateral sipes including the first lateral sipe and the second lateral sipe extending in different directions from each other. In this configuration, during cornering, each small block not only supports a small block adjacent to the tire width direction but also supports a small block adjacent to the tire circumferential direction, thereby increase a flexural rigidity of each block in the tire width direction. By increasing the flexural rigidity, the ground contact characteristics of the tire during braking is improved. Therefore, according to the tire described above, in the case where a tread pattern with blocks having a relatively small ground area are densely disposed is utilized, braking performance on a snow and ice road during cornering can be further improved. BRIEF DESCRIPTION OF DRAWINGS [FIG. 1] FIG. 1 is a partial plan view of a tread of a pneumatic tire 10.[FIG. 2] FIG. 2 is a partial enlarged plan view of the tread 20.[FIG. 3] FIG. 3 is a partial cross-sectional view of a block 100 including a circumferential sipe 120 (lateral sipe 130) along a sipe width direction and a tire radial direction TR.[FIG. 4] FIG. 4 is a partial plan view of a tread of a pneumatic tire 10A not according to the invention, but useful for understanding the present invention.[FIG. 5] FIG. 5 is a partial plan view of a tread of a pneumatic tire 10B according to a variant 1. MODES FOR CARRYING OUT THE INVENTION Hereinafter, embodiments will be described based on the drawings. Same functions and structures are denoted by the same or similar reference numerals, and the description thereof will be omitted accordingly. (1)Overall schematic structure of tire FIG. 1 is a part