Tire Tread Sipe Structure for Block Collapse Resistance
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Solution Overview
Problem
Existing tires with sipes in the tread blocks face issues of block collapse under load, leading to concentrated strain and potential cracks at the sipe bottom, compromising durability.
Innovation Solution
The tire design incorporates zigzag-shaped sipes with outward-protruding tie bars that terminate before the ground contact surface, positioned at different axial locations, enhancing block rigidity and preventing collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sipes are formed in the tread blocks to improve on-ice performance, then on-ice performance is improved, but block segments collapse under load causing strain concentration and cracks at the sipe bottom
Solution Approach 1:
Tie bars are pre-formed within the sipe structure to provide preliminary reinforcement before the block is subjected to load. These tie bars are positioned to engage the sipe walls in advance, creating a preventive reinforcement system that stops collapse before it occurs under operating conditions
Solution Approach 2:
The sipe structure is segmented into multiple sections by dividing it into multiple tie bars positioned at different locations. This segmentation allows each tie bar to independently reinforce specific portions of the sipe, distributing the reinforcement function across multiple elements rather than relying on a single continuous structure
2Ease of manufacture
If tie bars are positioned at the same location in all sipes, then manufacturing is simplified, but strain distribution is uneven leading to localized weakness
Solution Approach 1:
The tie bars are deliberately positioned asymmetrically within the sipe structure, with different axial positions for different tie bars. This asymmetric arrangement creates a more uniform distribution of reinforcement throughout the block, preventing localized weakness that would occur with symmetric, uniformly-positioned tie bars
Data Source
AI summary
A tire comprises a tread portion provided with blocks including a first block provided with a plurality of sipes. Each sipe comprises a zigzag portion in a cross section perpendicular to the sipe length direction, and a zigzag portion in a cross section parallel to the ground contacting top surface of the first block. Each of the sipes is provided with at least one tie bar protruding radially outwardly from the bottom of the sipe and terminating without reaching the ground contacting top surface. The sipes includes a first sipe having the tie bar at a first position in the tire axial direction, and a second sipe having the tie bar at a second position in the tire axial direction different from the first position.