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CN-122008737-A - Pneumatic tire

CN122008737ACN 122008737 ACN122008737 ACN 122008737ACN-122008737-A

Abstract

Provided is a pneumatic tire which is suitable for use as a tire for running on unpaved roads and which has improved running performance and cut resistance on unpaved roads. A pair of side blocks (21) facing each other across a side groove (22) extending in the tire width direction are provided in a side wall region located on the outer side in the tire width direction of a shoulder region of a tread portion (1), repetitive elements (20) comprising the side groove (22) and the pair of side blocks (21) are arranged at intervals in the tire circumferential direction, the tread of each side block (21) is formed in a concave-convex shape comprising a reference surface (21 a) located on the side of the side groove (22) and a step (21 b) located on the opposite side of the side groove (22) and rising from the reference surface (21 a), and a bottom rising portion (22 a) rising from the bottom of the side groove (22) and connecting between the pair of side blocks (21) is provided.

Inventors

  • YASUYUKI YOSHIDA

Assignees

  • 横滨橡胶株式会社

Dates

Publication Date
20260512
Application Date
20180725
Priority Date
20170727

Claims (9)

  1. 1. A pneumatic tire comprising a tread portion extending in a tire circumferential direction and having a ring shape, a pair of side portions disposed on both sides of the tread portion, and a pair of bead portions disposed on inner sides of the side portions in a tire radial direction, A pair of side blocks are provided in a side wall region located on the outer side in the tire width direction of a shoulder region of the tread portion so as to face each other with side grooves extending in the tire width direction interposed therebetween, and repeating elements each composed of these side grooves and the pair of side blocks are arranged at intervals in the tire circumferential direction, The tread of each sidewall block has a concave-convex shape composed of a reference surface located on the sidewall groove side and a step portion located on the opposite side of the sidewall groove and rising from the reference surface, a V-shaped notch is provided on the side surface of the step portion on the reference surface side, The sidewall groove has a bottom rise portion rising from a groove bottom and joining between the pair of sidewall blocks.
  2. 2. A pneumatic tire according to claim 1, wherein, The sidewall blocks included in the repeating element each have a shape such that the block width converges toward the sidewall groove as the sidewall blocks are located inward in the tire radial direction.
  3. 3. A pneumatic tire according to claim 1 or 2, wherein, The ratio A/SH of the vertical distance A measured from the ground contact end position of the tread portion toward the radial inner end of the sidewall block to the tire cross-section height SH is 0.15-0.50.
  4. 4. A pneumatic tire according to claim 1 or 2, wherein, The protruding amount of the reference surface of the sidewall block from the bottom of the sidewall groove is 8 mm-13 mm.
  5. 5. A pneumatic tire according to claim 1 or 2, wherein, The protruding amount of the step part of the sidewall block from the bottom of the sidewall groove is 110% -130% of the protruding amount of the reference surface of the sidewall block from the bottom of the sidewall groove.
  6. 6. A pneumatic tire according to claim 1 or 2, wherein, The area of the top surface of the step portion of the sidewall block when the sidewall block is viewed from the tread side of the sidewall block is 40% -60% of the area of the tread of the sidewall block as a whole.
  7. 7. A pneumatic tire according to claim 1 or 2, wherein, The ratio B/SH of the vertical distance B measured from the ground contact end position of the tread portion toward the tire radial direction to the radially inner end of the bottom raised portion to the tire section height SH is 0.20 to 0.40.
  8. 8. A pneumatic tire according to claim 1 or 2, wherein, The protruding amount of the bottom raised portion from the bottom of the sidewall groove is 3 mm-5 mm.
  9. 9. A pneumatic tire according to claim 1 or 2, wherein, The tread of the sidewall block has a peripheral portion with a ridge extending along the peripheral portion.

Description

Pneumatic tire The application relates to a divisional application of Chinese patent application with the application date of 2018, 7, 25, the application number of 201880047405.7 and the name of pneumatic tire. Technical Field The present invention relates to a pneumatic tire suitable as a tire for running on an unpaved road, and more particularly, to a pneumatic tire having improved running performance and cut resistance on an unpaved road (japanese: ) Is a pneumatic tire of the following formula (I). Background In a pneumatic tire used for running on an unpaved road such as uneven ground, muddy ground, snow road, sand ground, or rock ground, a lateral groove having a large number of edge components (japanese: ) A tread pattern with a large groove area and a block as a main body. In such a tire, traction performance is obtained by biting mud, snow, sand, stone, rock, etc. (hereinafter, they are collectively referred to as "mud, etc.) on the road surface, and running performance on the unpaved road is improved by preventing clogging of mud, etc. in the grooves. In particular, in a tire intended to run on a rocky ground, by providing blocks also in a sidewall region on the outer side in the tire width direction than a shoulder region (ground contact end), running performance (lock) on the rocky ground is improved (for example, refer to patent document 1). However, in such a tire, blocks are formed in the shoulder region and the sidewall region, but on the other hand, since the groove area is also increased in these regions, stones, rocks, and foreign matters on the road surface easily enter the grooves provided in the shoulder region and the sidewall region, and the groove bottom is easily damaged (cutting resistance is poor). Accordingly, measures for improving the running performance on unpaved roads (particularly, in rocky areas) by effectively biting mud into grooves without deteriorating the cutting resistance and for achieving a good balance between these performances have been sought. Prior art literature Patent literature Patent document 1 Japanese patent laid-open publication No. 2010-047251 Disclosure of Invention Problems to be solved by the invention The present invention aims to provide a pneumatic tire which is suitable for use as a tire for running on unpaved roads and which has improved running performance and cutting resistance on unpaved roads. Means for solving the problems The pneumatic tire according to the present invention for achieving the above object is characterized in that a pair of side blocks facing each other with a side groove extending in a tire width direction interposed therebetween are provided in a side wall region located at an outer side in the tire width direction of a shoulder region of the tread portion, a pair of side parts disposed on both sides of the side groove in the tire circumferential direction are arranged with a repeating element composed of the side groove and the pair of side blocks being spaced apart in the tire circumferential direction, a tread of each side block has a concave-convex shape composed of a reference surface located on the side of the side groove and a step part located on an opposite side of the side groove and raised from the reference surface, and the side groove has a bottom raised part raised from a groove bottom and connecting the pair of side blocks. ADVANTAGEOUS EFFECTS OF INVENTION In the present invention, since the sidewall blocks having the complex concave-convex shape are provided as described above, the edge components of the sidewall blocks are increased, and excellent edge effects can be exhibited by the sidewall blocks, so that the running performance (particularly, the locking performance) on an unpaved road can be improved. On the other hand, since the bottom raised portion is provided in the sidewall groove, the cut resistance can be improved. In addition, the pair of sidewall blocks adjacent to the sidewall groove are joined by the bottom raised portion, so that the pair of sidewall blocks and the bottom raised portion are improved in rigidity as a series of convex portions, and thus are advantageous in improving locking performance. In the present invention, it is preferable that each of the sidewall blocks included in the repeating element has a shape such that the block width converges toward the sidewall groove as the sidewall block is located inward in the tire radial direction. Accordingly, since the groove portions formed between the repeating elements adjacent to each other in the tire circumferential direction are widened toward the inner side in the tire radial direction with respect to the sidewall groove extending with a substantially constant width, they are alternately arranged in the tire circumferential direction, and therefore, the edge effect can be exerted on rocks or the like of various sizes, and the discharge performance of mud or the like is improved, which is advantageous for improving the run