Pneumatic Tire Variable Pitch Lateral Grooves
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Solution Overview
Problem
Pneumatic tires with variable pitch constructions face challenges in maintaining steering stability while ensuring uniformity, as the stiffness of land portions decreases with smaller pitches, leading to potential vibration issues.
Innovation Solution
The pneumatic tire design adjusts the volume ratio of lateral grooves by varying groove width, wall angle, and depth across different regions of the tread portion, increasing the ratio in shoulder regions and decreasing it in center regions to maintain uniformity and improve steering stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the volume of lateral grooves is increased to improve uniformity in shoulder regions, then uniformity is improved, but the stiffness of land portions decreases
Solution Approach 1:
The patent applies local quality by differentiating the volume ratio of lateral grooves between shoulder regions and center region. In shoulder regions, the volume ratio increases as pitch decreases to improve uniformity, while in the center region, the volume ratio decreases as pitch decreases to maintain stiffness. This regional differentiation allows each area to have optimized properties for its specific functional requirements.
2Reliability
If the amount of vulcanized rubber pressed in is made uniform to improve uniformity, then uniformity is improved, but the stiffness of land portions in center region decreases
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through region-specific volume ratio control. Instead of uniformly distributing vulcanized rubber, the invention allows the volume ratio of lateral grooves to vary by region: higher in shoulder regions for uniformity and lower in center region for stiffness maintenance.
3Object-affected harmful factors
If variable pitch construction is employed to disperse pitch noise, then noise properties are improved, but steering stability may decline due to decreased land portion stiffness
Solution Approach 1:
The patent maintains steering stability while preserving noise dispersion benefits by applying local quality to the center region. By decreasing the volume ratio of lateral grooves in the center region as pitch decreases, the invention ensures land portions maintain sufficient stiffness for steering stability, while shoulder regions still benefit from increased volume ratios for noise dispersion.
Solution Approach 2:
The patent segments the tread portion into shoulder regions and center region, allowing different volume ratio strategies for each segment. This segmentation enables the center region to prioritize stiffness for steering stability while shoulder regions prioritize uniformity and noise dispersion.
Data Source
AI summary
A pneumatic tire having a tread portion including land portions formed by vertical grooves provided in a tire circumferential direction and lateral grooves provided so as to intersect with the vertical grooves, the lateral grooves being disposed in the tire circumferential direction having a plurality of pitches P1, P2, and P3, wherein in a shoulder region of the tread portion, as a pitch decreases a volume ratio of the lateral grooves with respect to a pitch volume thereof increases; and, in a center region of the tread portion, as a pitch decreases the volume ratio of the lateral grooves with respect to a pitch volume thereof decreases.