Pneumatic Tire Bead Hatching for Rim Noise Reduction
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Solution Overview
Problem
Pneumatic vehicle tires with stiff sidewalls or run-flat tires often produce unpleasant smacking noises due to relative movements between the bead areas and the rim flanges, especially at low speeds or on wet surfaces, which existing hatching designs fail to adequately address.
Innovation Solution
The tire design features elevations with a triangular, rounded, or dome-shaped cross-section, supported well by the rim flanges, with depressions that absorb air and water, reducing noise through optimized cross-sectional areas and spacing, ensuring effective noise suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hatched pattern with raised sections is provided in the bead area contact points, then the durability of the bead areas is improved and premature wear is prevented, but squelching noises are generated due to the raised sections being squashed against the rim flange
Solution Approach 1:
The patent changes the geometric parameters of the hatching pattern, specifically setting the height of raised areas to 0.5-1.2mm and the cross-sectional area of depressions to at most 60% of the cross-sectional area of raised areas. These parameter optimizations reduce the squelching noise while maintaining the durability benefit of the hatched pattern.
2Object-generated harmful factors
If the cross-sectional area of depressions between raised areas is increased, then more air and water can be absorbed to reduce noise, but the support capability in the contact area is reduced
Solution Approach 1:
The patent optimizes the cross-sectional area ratio between depressions and raised areas to at most 60%, finding the optimal balance point where sufficient air and water absorption capacity is achieved while maintaining adequate support capability in the contact area between tire and rim flange.
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 significantly reduces or prevents smacking noises by stabilizing the tire on the rim flanges and managing air and water volumes within the depressions, effectively addressing noise issues at low speeds and in wet conditions.
Implementation Method 1
air and, in wet conditions, water are absorbed and distributed in the depressions
Data Source
Figure 1~3
Figure 4~5
AI summary
Pneumatic tires with bead areas, each of which has on its outer surface an annular circumferential area (7) with a hatching pattern consisting of a plurality of parallel or nearly parallel, and in particular identically shaped, raised areas (8, 8', 8", 8''') and depressions (9), wherein, when the tire is mounted on a rim (1), the area is located partly in the contact area with the inside of the rim flange (1b) and partly radially outside the contact area. The raised areas (8, 8', 8", 8''') have a height (h) of 0.5 mm to 1.2 mm, wherein the cross-sectional area of the depressions (9) between the raised areas (8, 8', 8", 8''') corresponds to at most 60% of the cross-sectional area of the raised areas (8, 8', 8", 8''').