Closed-Sipe Tire Tread Layout for Heel-and-Toe Wear Reduction
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Solution Overview
Problem
Tires with closed sipes tend to experience uneven wear, such as heel-and-toe wear, due to repeated opening and closing during contact with the ground, which affects their performance and longevity.
Innovation Solution
The tire design includes closed sipes with a specific geometry and tie bars that protrude outward in the radial direction, where the tie bar's center is closer to the intersecting portion, reducing uneven wear by inhibiting deformation and maintaining sipe integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If closed sipes are aligned in the tire axial direction and overlap each other, then on-ice braking/driving performance is enhanced, but uneven wear such as heel-and-toe wear is easily generated around the closed sipes
Solution Approach 1:
Tie bars are pre-installed at specific positions within the closed sipes, particularly at intersecting portions where the first sipe piece and third sipe piece intersect. These tie bars are positioned in advance to prevent the sipe pieces from separating during tire operation, thereby preventing uneven wear before it occurs while maintaining the overlapping closed sipe configuration for on-ice performance
2Ease of operation
If closed sipes are repeatedly opened and closed during contact with the ground, then tread portion is brought into contact with the ground, but uneven wear is generated around the closed sipes
Solution Approach 1:
Tie bars are installed in advance at the intersecting portions of the sipe pieces to prevent separation during the repeated opening and closing cycles that occur during normal tire operation. This preliminary reinforcement allows the tread to contact the ground effectively while preventing the wear damage that would otherwise occur during these cyclic movements
Data Source
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.