Shoulder blocks for pneumatic tires and pneumatic tires employing such shoulder blocks in treads

摘要

A shoulder block (1) includes a thin groove (2) formed substantially at the center in the circumferential direction of a tread, transverse sipes (4) circumferentially spaced from the thin groove (2), and at least one circumferential sipe (3) extending substantially circumferentially without intersecting the thin groove (2) or the transverse sipes (3), in such a manner that a circumferential component of the circumferential sipe is greater than its transverse component. The thin groove (2) extends widthwise of the tread, and has a length substantially equal to the width of the block. The transverse sipe (4) extends widthwise of the tread, and opens at the side wall (1a) of the block on the side of the center of the tread. Opening widths of the thin groove and the transverse and circumferential sipes are not more than 3.0 mm. The difference h₁-h₂ between a depth h₁ of the thin groove and a depth h₂ of the transverse sipe is 0.75h₁ ≧ h₁ - h₂ ≧ 0.3h₁, and depths H and h₂ of the circumferential sipe and the transverse sipe are such that H ≧ h₂, and the circumferential entire length L of the circumferential sipe and an average length ℓ of the block are such that L ≧ 0.5ℓ.