Pneumatic Tire Sipe Depth Variation for Dry Stability
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Solution Overview
Problem
Pneumatic tires with block-patterned treads and sipes deteriorate in steering stability on dry roads and durability due to reduced rigidity, which compromises their off-road performance.
Innovation Solution
A pneumatic tire design with a tread portion divided into specific areas, featuring crown sipes, middle sipes, and shoulder sipes of varying depths and orientations, strategically positioned to maintain rigidity and facilitate deformation for improved traction and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sipes of the same depth are formed in blocks to reduce rigidity and improve off-road performance, then off-road performance is improved, but steering stability on dry roads deteriorates and blocks become prone to chipping
Solution Approach 1:
The patent applies local quality by varying sipe depths according to the functional requirements of different tread areas. Crown sipes have smaller depths (0.5-2.0mm) to maintain rigidity for steering stability, while middle sipes have larger depths (2.0-4.0mm) to enhance deformation and grip for off-road performance. This localized differentiation resolves the contradiction by optimizing each area for its specific function.
Solution Approach 2:
The patent segments the tread portion into three distinct areas (crown, middle, and inner shoulder) with different sipe depth characteristics. This segmentation allows each zone to independently contribute to either rigidity or deformability based on its sipe configuration, thereby simultaneously achieving steering stability and off-road performance without compromise.
2Adaptability or versatility
If sipes of the same depth are formed in blocks to facilitate deformation, then block deformation is improved, but durability deteriorates due to block chipping
Solution Approach 1:
The patent implements local quality by assigning different sipe depths to different block regions. Crown blocks have shallow sipes that preserve structural integrity and resist chipping, while middle blocks have deeper sipes that enable greater deformation for improved grip. This localized approach allows durability and deformability to coexist by matching each property to the appropriate location.
Data Source
AI summary
A pneumatic tire includes a tread portion being provided with blocks which are provided with sipes. When the tread portion is virtually divided into a crown area having a ¼ tread ground-contact width centered on a tire equator, a pair of middle areas each having a ⅛ tread ground-contact width and being adjacent to axially each side of the crown area and a pair of inner shoulder areas each having a ⅛ tread ground-contact width and being adjacent to axially outside the middle areas, the sipes comprise crown sipes having main portions included in the crown area, middle sipes having main portions included in the middle areas and shoulder sipes having main portions included in the inner shoulder areas. Depths of the crown sipes are smaller than depths of the middle sipes, and depths of the shoulder sipes are smaller than the depths of the middle sipes.