Pneumatic Tire Sipe Chamfer Geometry for Dry Wet Stability
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Solution Overview
Problem
Pneumatic tires face a trade-off in steering stability performance, where increasing sipes for improved wet road stability compromises dry road stability due to reduced rib rigidity and insufficient edge effects from chamfered sipes.
Innovation Solution
A pneumatic tire design featuring sipes with chamfered edges, where the chamfered portion projects outward in the tire radial direction, straddling the rib's maximum projection, and satisfying specific curvature and width relationships, enhances drainage and stability on both dry and wet 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 improved, but the rigidity of the ribs decreases, causing steering stability performance on dry road surfaces to deteriorate
Solution Approach 1:
The sipes are provided with chamfered portions only at specific edges rather than uniformly across all sipes. This local modification concentrates the drainage enhancement function at critical locations while preserving the structural integrity and rigidity of the ribs in other areas, thereby resolving the contradiction between wet road stability and dry road stability.
Data Source
AI summary
Provided is a pneumatic tire capable of providing improved steering stability performance on dry road surfaces and improved steering stability performance on wet road surfaces in a compatible manner. A sipe (12) includes at least one end communicating with a main groove (9) and a chamfered portion (13) in at least one edge, and the chamfered portion (13) includes at least one end open to the main groove (9). In a meridian cross-sectional view, a profile line (L1) projects further to an outer side in a tire radial direction than a reference tread profile line (L0). A radius of curvature (TR) (mm) of the reference tread profile line (L0) and a radius of curvature (RR) (mm) of the profile line (L1) of a rib (10) satisfy a relationship of TR>RR. The chamfered portion (13) is disposed straddling a maximum projection position (P) of the profile line (L1) of the rib (10). A maximum projection amount (D) (mm) of the rib (10) with respect to the reference tread profile line (L0) and a maximum width (W) (mm) of the chamfered portion (13) satisfy a relationship of 0.05 mm2<W×D<1.50 mm2.