Pneumatic Tire Sipe Chamfering for Wet-Dry Stability Balance
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Solution Overview
Problem
Pneumatic tires face challenges in achieving simultaneous improvement of steering stability on both dry and wet road surfaces while maintaining noise performance, as excessive sipes for wet stability compromise dry surface stability and noise levels.
Innovation Solution
A pneumatic tire design featuring sipes with chamfered edges on both sides, where the chamfered portions are shorter than the sipe length, and non-chamfered regions enhance drainage and edge effects, with one end opening into the main groove and the other terminating within the rib, optimizing the chamfer depth and sipe width relationship to balance stability and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If many sipes are disposed in the tread portion to improve steering stability on wet road surfaces, then drainage properties are ensured, but steering stability on dry road surfaces and uneven wear resistance decrease due to lowering of rib rigidity
Solution Approach 1:
The patent applies local quality by differentiating the rib structure into two distinct regions: a first rib portion with sipes for wet surface drainage, and a second rib portion without sipes for maintaining rigidity on dry surfaces. This localized differentiation allows each region to optimize its function - the siped region handles water evacuation while the non-siped region provides structural stiffness, thereby resolving the contradiction between wet surface performance and dry surface stability.
2Reliability
If many sipes are disposed in the tread portion to improve steering stability on wet road surfaces, then drainage properties are ensured, but noise from the tire increases due to popping sounds and pattern noise
Solution Approach 1:
The patent reduces noise by applying sipes only locally in the first rib portion rather than uniformly across the entire tread. This localized sipe arrangement minimizes the total number of sipes, thereby reducing the sources of popping sounds and pattern noise while still providing adequate drainage functionality in the critical wet surface contact region.
Solution Approach 2:
The patent segments the rib structure into multiple portions with different characteristics - the first rib portion contains sipes for drainage while the second rib portion remains solid for noise reduction. This segmentation allows the tire to achieve wet surface performance without the penalty of excessive noise generation that would result from a uniform siped design.
3Reliability
If chamfered portions are formed on edges of sipes to enhance drainage effect, then steering stability on wet road surfaces is improved, but steering stability on dry road surfaces decreases due to reduced rib rigidity
Solution Approach 1:
The patent applies chamfered portions only to the edges of sipes in the first rib portion, while the second rib portion maintains full rigidity without chamfered edges. This localized application of chamfering provides enhanced drainage capability where needed while preserving the structural integrity and rigidity of the tire rib on dry surfaces, thereby resolving the contradiction between wet surface drainage performance and dry surface stability.
Data Source
AI summary
A sipe of a pneumatic tire includes an edge on a leading side and an edge on a trailing side, chamfered portions shorter than a sipe length of the sipe formed on respective leading and trailing side edges, and non-chamfered regions on which no other chamfered portion exists on portions opposing respective chamfered portions in the sipe. One end portion of the sipe opens into a main groove and another end portion terminates within a rib. A maximum depth x (mm) of the sipe and a maximum depth y (mm) of the chamfered portion satisfy x×0.1≤y≤x×0.3+1.0. A sipe width of the sipe is constant in a range from a sipe portion positioned inside in a tire radial direction of the chamfered portion to a groove bottom of the sipe.