Closed Sipe Tie-Bar Layout for Heel-and-Toe Wear Reduction
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Solution Overview
Problem
Existing tires with closed sipes are prone to uneven wear, particularly heel-and-toe wear, due to the repeated opening and closing of sipes during contact with the ground, which is exacerbated by high loads in vehicles like light trucks and vans.
Innovation Solution
The tire design incorporates closed sipes with a width of not greater than 1.5 mm, aligned in the tire axial direction, featuring intersecting sipe pieces and tie bars that protrude outward in the tire radial direction, with the tie bars positioned strategically to inhibit deformation and wear, particularly at intersecting points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If closed sipes are aligned in the tire axial direction to enhance on-ice braking/driving performance, then on-ice performance is improved, but uneven wear such as heel-and-toe wear is easily generated around the closed sipes
Solution Approach 1:
The patent applies local quality by making the sipe bottom locally protrude outward in the tire radial direction to form a tie bar. This localized structural modification reinforces specific high-wear areas (the sipe bottoms) without changing the overall sipe configuration, thereby maintaining on-ice performance while reducing uneven wear.
Solution Approach 2:
The tie bar structure is pre-formed during tire manufacturing to prevent wear before it occurs. By having the sipe bottom protrude outward as a tie bar from the beginning, the structure is prepared in advance to resist the opening and closing forces that cause heel-and-toe wear during tire operation.
2Duration of action of stationary object
If the sipe bottom locally protrudes outward to form a tie bar, then uneven wear is reduced, but the structural complexity of the sipe increases
Solution Approach 1:
The sipe structure is segmented into distinct functional parts: the sipe pieces forming the main body and the sipe bottom forming the tie bar. This segmentation allows each part to perform its specific function - the sipe pieces for cutting and the protruding sipe bottom for wear resistance - while maintaining overall structural clarity.
Solution Approach 2:
The sipe bottom serves multiple functions: it forms the tie bar structure that prevents wear, maintains sipe alignment, and contributes to the overall structural integrity. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in structural complexity.
Data Source
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AI summary
Provided is a tire that allows reduction of uneven wear such as heel-and-toe wear around a plurality of closed sipes. The tire includes a tread portion 2. A plurality of closed sipes 8 are aligned in a tire axial direction in a land portion 4 of the tread portion 2. Each of the closed sipes 8 includes a sipe bottom 8d, a first end 8a and a second end 8b, a first sipe piece 11, a second sipe piece 12, a third sipe piece 13, and at least one tie bar 20. The closed sipes 8 aligned in the tire axial direction overlap each other in the tire axial direction and a tire circumferential direction. The tie bar 20 includes a first tie bar 21. A center, in a sipe length direction, of the first tie bar 21 is disposed closer to a first intersecting portion 18 than a center, in a length direction, of the first sipe piece 11 is. A distance from the first tie bar 21 to the first intersecting portion 18 is not greater than 25% of a length of the first sipe piece 11.