Pneumatic Tire Micro Sipes for On-Ice Grip and Land Rigidity
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Solution Overview
Problem
Existing pneumatic tires, particularly studless tires, face a challenge in achieving a balance between the rigidity of the land portion and effective water discharge through sipes, which limits on-ice gripping performance.
Innovation Solution
The tire features micro sipes with distinct elements extending in different directions, where one element is shorter than the other, and the sipe depth varies to maintain rigidity while enhancing water drainage, combined with long sipes for improved drainage and gripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sipes are arranged at high density to improve water discharge, then on-ice gripping performance is improved, but rigidity of the land portion decreases
Solution Approach 1:
The sipes are segmented into multiple elements (first element and second element) with different extension lengths and directions. This segmentation allows the sipes to effectively discharge water in multiple directions while the varied structure maintains land portion rigidity by preventing excessive flexibility in any single direction.
Solution Approach 2:
Different portions of the sipe structure have different properties: the first element extends longer to provide effective water discharge paths, while the second element extends shorter to maintain structural integrity. The sipe depth also varies, with maximum depth h1 in the first element direction and minimum depth h2 in the second element direction, creating localized variations that balance drainage and rigidity.
2Reliability
If sipe depth is increased to enhance water discharge, then on-ice gripping performance is improved, but rigidity of the land portion decreases
Solution Approach 1:
The sipe depth is not uniform but varies locally: maximum sipe depth h1 is provided in the extension direction of the first element for effective water discharge, while minimum sipe depth h2 is provided in the extension direction of the second element to maintain rigidity. This local variation in depth allows the structure to discharge water effectively where needed while maintaining strength where required.
Solution Approach 2:
The sipe structure is asymmetric with the first element having a longer extension length and the second element having a shorter extension length. The sipe depths are also asymmetric with h1 > h2. This asymmetry allows differential water discharge capability in different directions while maintaining overall structural rigidity through the shorter, shallower second element.
Data Source
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AI summary
A pneumatic tire includes at least one land portion on a tread surface. A plurality of micro sipes are disposed in at least one of the land portions. The micro sipes each have a first element and a second element extending in a direction different from the first element from one end of the first element. An extension length of the second element is shorter than an extension length of the first element. One end of the first element and one end of the second element are in communication. The other end of the first element terminates within the land portion. The other end of the second element terminates within the land portion. A minimum sipe depth h2 in the extension direction of the second element is smaller than a maximum sipe depth h1 in the extension direction of the first element.