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US 5,385,189 AGranted
Pneumatic tire with paired sides in the tread
AssigneeBridgestone Corporation
InventorsNamito Aoki, Yasufumi Ichiki, Chishiro Tanabe
Life of this patent
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AssigneeBridgestone Corporation
InventorsNamito Aoki, Yasufumi Ichiki, Chishiro Tanabe
Estimating the term…
A pneumatic tire includes a plurality of blocks, each having a narrow area interposed between one set of two sipes which extend substantially in a transverse direction of the tire and wide areas positioned respectively at both sides of the narrow area across the sipes. An average distance H2 from a tire tread surface of the narrow area to bottom portions of the sipes is less than an average distance H1 from tire tread surfaces of the wide areas to the bottom portions of the sipes. Expanded portions may be provided at the bottom portions of the two sipes. A ratio W2/W1 of a length W2 of the narrow area in the transverse direction of the tire to a length W1 of the wide areas in the transverse direction of the tire may satisfy 0.50.ltoreq.W2/W1.ltoreq.0.95. A length, in the circumferential direction of the tire, of at least one side end portion of the narrow area may be longer than a length, in the circumferential direction of the tire, of a central portion of the narrow area. In a vulcanization mold for forming a green tire, a pair of blades for forming a pair of sipes are provided at a bottom portion of a concave portion for forming a block portion. A vent hole is also provided at a bottom portion of an area between the blades. A method of manufacturing a pneumatic tire using the mold is provided.
A pneumatic tire comprising a plurality of blocks, each block being located on a ground facing surface of the tire and having at least one set of two sipes extending substantially in a transverse direction of the tire, said at least one set of two sipes defining a first area therebetween and second areas on opposite sides of said first area in a circumferential direction of the tire, the first area being a narrow area having a width TS in a circumferential direction of the tire less than a width TL of each second area in the circumferential direction of the tire, the second areas being wide areas, each sipe having a depth in a radial direction of the tire and a groove width in the circumferential direction of the tire, the groove width of each sipe adjacent a radially innermost bottom portion of the sipe being larger than the groove width of each sipe adjacent a radially outermost top portion of the sipe to define expanded portions at the bottom portion of the sipes, a ratio L/TS of a shortest distance L between the expanded portions of the sipes to an average length TS of the first area in the circumferential direction of the satisfying 0.7.ltoreq.L/TS.ltoreq.1.5, the bottom portions of the sipes being expanded in convex shapes extending in opposite directions towards the wide areas of the block in the circumferential direction of the tire.
A pneumatic tire comprising a plurality of blocks, each block being located on a ground facing surface of the tire and having at least one set of two sipes extending substantially in a transverse direction of the tire, said at least one set of two sipes defining a first area therebetween and second areas on opposite sides of said first area in a circumferential direction of the tire, the first area being a narrow area having a width TS in a circumferential direction of the tire less than a width TL of each second area in the circumferential direction of the tire, the second areas being wide areas, each sipe having a depth in a radial direction of the tire and a groove width in the circumferential direction of the tire, the groove width of each sipe adjacent a radially innermost bottom portion of the sipe being larger than the groove width of each sipe adjacent a radially outermost top portion of the sipe to define expanded portions at the bottom portion of the sipes, a ratio L/TS of a shortest distance L between the expanded portions of the sipes to an average length TS of the first area in the circumferential direction is approximately equal to 1, the bottom portions of the sipes being expanded in convex shapes extending in opposite directions towards the wide areas of the block in the circumferential direction of the tire.
Dependencies are inferred from the claim text.