Pneumatic Tire Sipe Chamfering for Dry Wet Stability
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Solution Overview
Problem
Pneumatic tires face a trade-off between steering stability on dry and wet road surfaces, where increasing sipes for improved wet surface stability reduces rib rigidity and worsens dry surface stability.
Innovation Solution
A pneumatic tire design with sipes having chamfered edges on both sides and non-chamfered regions, where the total volume of chamfered portions on the vehicle's inner side is greater than on the outer side, optimizing drainage and edge effects for enhanced stability on both surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of sipes are disposed in a tread portion to improve steering stability performance on wet road surfaces, then drainage properties are ensured and steering stability on wet surfaces is improved, but the rigidity of the ribs decreases and steering stability performance on dry road surfaces deteriorates
Solution Approach 1:
The patent applies local quality by providing chamfered portions only at specific locations (edges on leading and trailing sides of sipes) rather than uniformly across all sipes. This localized chamfering maintains rib rigidity in non-chamfered regions while improving drainage and water film removal at critical edge positions, thereby resolving the contradiction between wet surface stability and rib rigidity.
Solution Approach 2:
The patent employs asymmetry by making the total volume of chamfered portions on the vehicle mounting inner side (SIN) greater than on the outer side (SOUT). This asymmetric chamfer distribution optimizes performance for different mounting positions and driving conditions, improving steering stability on wet surfaces while maintaining adequate rib rigidity.
2Reliability
If chamfered portions are provided on sipes to improve drainage effect and steering stability on wet road surfaces, then water film removal is enhanced, but the chamfered area increases which reduces steering stability performance on dry road surfaces
Solution Approach 1:
The patent limits chamfered portions to only the edges on the leading and trailing sides of sipes, rather than chamfering entire sipe surfaces. This localized approach concentrates drainage functionality where most needed while minimizing the total chamfered area, thus improving wet surface performance without significantly compromising dry surface stability.
Solution Approach 2:
The patent applies partial action by providing chamfered portions only at critical edge locations rather than uniformly across all sipe surfaces. This selective chamfering achieves sufficient drainage and water film removal effectiveness while keeping the total chamfered area minimal, resolving the contradiction between wet performance improvement and dry performance maintenance.
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
The design improves steering stability on both dry and wet road surfaces by minimizing the chamfered area, maintaining rib rigidity, and effectively removing water films, resulting in balanced performance.
Implementation Method 1
the drainage effect can be improved with the chamfered portions
Implementation Method 2
a water film can be effectively removed by the edge effect in the non-chamfered regions
Data Source
AI summary
A pneumatic tire is provided with a sipe including an edge on a leading side and an edge on a trailing side. The edge on the leading side and the edge on the trailing side each include a chamfered portion shorter than a sipe length of the sipe. A non-chamfered region in which other chamfered portions are not present is provided at portions facing the chamfered portions of the sipe. For all chamfered portions, including at least the chamfered portions of the sipe, formed on grooves other than main grooves, a total volume SIN of the chamfered portions located on a vehicle mounting inner side and a total volume SOUT of the chamfered portions located on a vehicle mounting outer side satisfy a relationship SIN>SOUT.