Tire Tread Bridge Geometry for Center Drainage and Rigidity
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Solution Overview
Problem
Pneumatic tires with circumferential grooves and lug grooves face reduced water drainage performance at the center portion in the tire width direction, which can be exacerbated by reinforcement features intended to improve rigidity and traction.
Innovation Solution
A pneumatic tire design featuring a bridge with a bulged bottom surface in the lug groove near the circumferential groove, having a trapezoidal cross-sectional shape with tapered surfaces, which enhances the rigidity of the center land portion while facilitating water flow from the circumferential groove to the lug groove, reducing dependence on tire rotational direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a bridge with a bulged bottom surface is formed at the lug groove near the circumferential groove to improve rigidity of the center land portion, then the rigidity is improved, but water drainage performance at the center portion is significantly reduced
Solution Approach 1:
The bridge is designed with asymmetric geometry featuring tapered surfaces where one surface is inclined at a first angle to the bottom surface while the other surface is inclined at a second angle, creating an asymmetric cross-sectional shape. This asymmetric design allows water to flow preferentially along the tapered surfaces toward the circumferential groove while maintaining the structural rigidity provided by the bridge, thus resolving the contradiction between rigidity improvement and water drainage performance
Solution Approach 2:
The bridge incorporates localized tapered surfaces with specific inclination angles at different locations. The first tapered surface has a different inclination angle than the second tapered surface, creating local variations in surface geometry that facilitate water flow in specific directions while providing rigidity support where needed, thereby balancing structural requirements with drainage functionality
2Force
If a reinforcement bar is provided on the bottom surface of the lug groove to maintain traction and energy distribution, then traction performance is maintained, but water drainage performance is significantly reduced
Solution Approach 1:
The bridge design changes the geometric parameters of the lug groove reinforcement by incorporating tapered surfaces with specific inclination angles. Instead of using a conventional reinforcement bar with vertical sides, the tapered geometry modifies the parameters of the groove structure to allow water flow paths along the inclined surfaces, maintaining structural integrity and traction while improving water drainage performance
Data Source
AI summary
A tire has a tread including: a first circumferential groove which is closest to a center in a tire width direction among a plurality of circumferential grooves; center land portions placed adjacent to the first circumferential groove at a side near the center in the tire width direction, and a lug groove which extends between a plurality of the center land portions, and which opens to a side near the first circumferential groove. A bridge having a bottom surface which is bulged is formed at a portion of the lug groove near the first circumferential groove. The bridge has a cross-sectional shape of a trapezoid with tapered surfaces in which side surfaces of the lug groove at an end near a center in a longitudinal direction and an end near the first circumferential groove are inclined with heights thereof reduced toward corresponding ends of the bridge.