| CPC B60C 11/1376 (2013.01) [B60C 11/11 (2013.01); B60C 11/1369 (2013.01); B60C 11/03 (2013.01); B60C 2200/10 (2013.01); B60C 2200/14 (2013.01)] | 17 Claims |
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1. A tyre for running on rough terrain comprising a tread portion, wherein
the tread portion includes a first tread edge, a second tread edge, a shoulder region, a crown region, and a middle region,
the shoulder region extends inwardly in the tyre axial direction from the first tread edge and has a development width of one sixth of a tread development width,
the middle region is arranged on an inner side in the tyre axial direction of the shoulder region and has a development width of one sixth of the tread development width,
the crown region is arranged on an inner side in the tyre axial direction of the middle region and has a development width of one third of the tread development width,
the tread portion comprises a plurality of blocks and tread crossing grooves extending between the first tread edge and the second tread edge without intersecting the plurality of the blocks,
the plurality of the blocks includes a plurality of shoulder blocks arranged in the shoulder region, a plurality of crown blocks arranged in the crown region, and a plurality of middle blocks arranged in the middle region, wherein the total number of blocks in each of the shoulder, crown, and middle regions is the same,
in a development view of the tread portion, each of the tread crossing grooves includes a soil discharging space having a width of at least 10 mm or more and extending linearly so as to connect between the first tread edge and the second tread edge,
the soil discharging space is inclined at an angle of 30 degrees or more and 50 degrees or less with respect to a tyre axial direction,
the tread crossing grooves include first grooves each inclined to one side with respect to the tyre axial direction, and second grooves each inclined in an opposite direction to the first grooves, such that circumferentially adjacent first and second grooves extend toward each other to form a narrow portion on one tread edge and away from each other to form a wide portion on an opposite tread edge,
the tread portion includes a first region defined by circumferentially adjacent first and second grooves to include the crown region as well as the middle region and shoulder region that are adjacent to the narrow portion formed by the first and second grooves,
in the first region, the total number of middle blocks is greater than the total number of shoulder blocks,
in the first region, the total number of crown blocks is greater than the total number of middle blocks,
the shoulder blocks are connected with middle blocks by shoulder tie bars,
the shoulder tie bars include first shoulder tie bars and second shoulder tie bars,
two first shoulder tie bars extend from one shoulder block to be connected with different middle blocks, and
two second shoulder tie bars extend from one middle block to be connected with different shoulder blocks.
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