Patent ID: 9566829
Date: 2017-02-14
CPC Classifications: B60C

Claim:
1. A pneumatic tire including a tread with land portions each having one or more sipes, wherein: the sipe has a depth (D) and comprises, as seen in a widthwise section of the sipe and in a depth direction from the tread surface (S), a perpendicular portion extending along a normal line of the tread surface at a center of an opening of the sipe, and a bend portion bending across the perpendicular portion toward one side and then toward the other; the bend portion comprises, in an order in the depth direction, a first sub-bend point in a depth region of D/7-D/2, a main-bend point in a depth region of D/4-3D/4, and a second sub-bend point in a depth region of D/2-6D/7, wherein a first inclined section is formed between the first sub-bend point and the main-bend point, and a second inclined section directly connects between the main-bend point and the second sub-bend point; the first inclined section forms an acute angle θ1 relative to a tangent at an opening end of the sipe in the tread surface, wherein the acute angle θ1 of the first inclined section is 30°≦θ1≦60°, and the second inclined section forms an acute angle θ2 relative to said tangent, wherein the acute angle θ2 of the second inclined section is 30°≦θ2≦60°; the bend portion further comprises a third inclined section extending continuously from a bottom of the perpendicular portion to the first sub-bend point and inclined toward an opposite direction of an extending direction of the first inclined section relative to the normal direction, and a fourth inclined section extending continuously from the second sub-bend point to an end of the fourth inclined section and inclined toward an opposite direction of an extending direction of the second inclined section relative to the normal direction; and each area of the first inclined section and the second inclined section is larger than each area of the third inclined section and the fourth inclined section; wherein each of the areas of the first inclined section, the second inclined section, the third inclined section, and the fourth inclined section is calculated by multiplying a respective extending length thereof and a longitudinal length of the sipe.