Pneumatic Tire Sipe Width Gradient for Wear Resistance
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Solution Overview
Problem
The design of sipes in pneumatic tire tread surfaces faces a challenge in balancing wear resistance, as sipe width affects both wear suppression during vertical load and shear force reduction during kicking-out, with narrow sipes increasing wear due to excessive shear force and wide sipes failing to enhance frictional force under vertical load.
Innovation Solution
A pneumatic tire design featuring sipes with varying widths along their depth and extending directions, maximizing at specific positions to ensure contact and friction under load while allowing tread rubber to flow into the sipes during kicking-out, reducing shear force, with preferred sipe widths ranging from 0.3 to 1.0 mm and positions optimized to 30-70% of sipe depth and 40-60% of sipe length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sipe width is made small to increase frictional force between sipe wall surfaces under vertical load, then the rigidity of tread rubber is enhanced and wear is suppressed, but excessive shear force is generated in the tread rubber during kicking-out and wear is likely to occur
Solution Approach 1:
The sipe width is designed to vary at different locations: it is small (0.2-0.5mm) at the tread surface to enhance frictional force and rigidity under vertical load, and gradually increases toward the sipe bottom to reduce shear force during kicking-out. This local variation in sipe width allows the same structure to serve dual functions of enhancing rigidity and reducing shear force at different positions.
Solution Approach 2:
The invention transitions from considering only the horizontal dimension (sipe width at tread surface) to incorporating the vertical dimension (sipe depth direction). By designing the sipe width to gradually increase from the tread surface toward the sipe bottom, the invention utilizes the depth dimension to create a gradient structure that optimizes both frictional force and shear force characteristics.
2Object-generated harmful factors
If the sipe width is made large to reduce shear force during kicking-out, then the tread rubber can flow into the sipe and wear is suppressed, but the sipe wall surfaces fail to contact sufficiently under vertical load and frictional force is not enhanced
Solution Approach 1:
The sipe width is designed to vary at different locations: it is small (0.2-0.5mm) at the tread surface to enhance frictional force and rigidity under vertical load, and gradually increases toward the sipe bottom to reduce shear force during kicking-out. This local variation in sipe width allows the same structure to serve dual functions of enhancing rigidity and reducing shear force at different positions.
Solution Approach 2:
The invention transitions from considering only the horizontal dimension (sipe width at tread surface) to incorporating the vertical dimension (sipe depth direction). By designing the sipe width to gradually increase from the tread surface toward the sipe bottom, the invention utilizes the depth dimension to create a gradient structure that optimizes both frictional force and shear force characteristics.
3Strength
If the sipe width is made extremely small to enhance rigidity, then frictional force between sipe wall surfaces is maximized under vertical load, but the sipe structure becomes too narrow and may not effectively suppress wear through rubber flow during kicking-out
Solution Approach 1:
The sipe width is designed to vary at different locations: it is small (0.2-0.5mm) at the tread surface to enhance frictional force and rigidity under vertical load, and gradually increases toward the sipe bottom to reduce shear force during kicking-out. This local variation in sipe width allows the same structure to serve dual functions of enhancing rigidity and reducing shear force at different positions.
Solution Approach 2:
The invention transitions from considering only the horizontal dimension (sipe width at tread surface) to incorporating the vertical dimension (sipe depth direction). By designing the sipe width to gradually increase from the tread surface toward the sipe bottom, the invention utilizes the depth dimension to create a gradient structure that optimizes both frictional force and shear force characteristics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively improves wear resistance by securing tread rubber rigidity under load and reducing shear force during kicking-out, thereby enhancing both wear suppression and steering stability.
Implementation Method 1
the tread rubber 50 may flow (expand) into the sipe 400 and, in accordance therewith, the shear force of the tread rubber 50 is reduced
Implementation Method 2
the larger the frictional force generated between a pair of sipe wall surfaces facing each other in a sipe 400 when the sipe wall surfaces come into contact with each other, the higher the rigidity of a tread rubber 50
Data Source
AI summary
Wear resistance is improved. To that end, a pneumatic tire of the disclosure herein includes, on a tread surface 1, a sipe 4 extending in a direction intersecting a tire circumferential direction. A sipe width of the sipe becomes maximum at a predetermined depth direction position P1 at predetermined extending direction position P2 of the sipe, and gradually increases at the predetermined depth direction position P1 from both ends in the sipe extending direction to the predetermined extending direction position P2, and also gradually increases at the predetermined extending direction position P2 from both ends in the sipe depth direction to the predetermined depth direction position P1.