Heavy Load Tire Shoulder Rib Wear Resistance
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Solution Overview
Problem
Conventional pneumatic tires for heavy loads experience uneven wear in the shoulder region due to a decrease in rigidity of the sacrifice rib as the tire wears, leading to accelerated wear and reduced resistance to uneven wear.
Innovation Solution
The tire features at least three circumferential ribs with a circumferential fine groove on the outermost side, a shoulder rib on the inner side, and a sacrifice rib on the outer side, with specific dimensions and angles to maintain contact pressure and rigidity, including an offset sacrifice rib surface and angled circumferential fine groove to reduce slippage and enhance wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the circumferential fine groove is positioned at the outer edge of the shoulder rib with a large offset angle, then uneven wear resistance is improved in the early stage, but the rigidity of the shoulder rib decreases as the tire wears, accelerating uneven wear
Solution Approach 1:
The patent optimizes the offset amount of the circumferential fine groove from the outer edge of the shoulder rib to be within 0.5-2.0mm, and controls the groove angle to be 10-30 degrees relative to the circumferential direction. These parameter optimizations balance the competing requirements of inducing sufficient wear on the sacrifice rib while maintaining adequate rigidity of the shoulder rib structure.
Solution Approach 2:
The patent designs the shoulder rib as a dynamic structure where the sacrifice rib portion is intended to wear down over time, gradually changing the load distribution and contact characteristics. This dynamic wear process allows the tire to adapt to operating conditions, with the outer edge portion sacrificing material to prevent uneven wear of the inner shoulder region.
2Loss of substance
If the sacrifice rib surface is offset and recessed significantly from the profile line, then the sacrifice rib wears more actively, but road contact pressure at the outer edge decreases, accelerating uneven wear
Solution Approach 1:
The patent precisely controls the offset amount of the circumferential fine groove from the outer edge of the shoulder rib to be within 0.5-2.0mm for new tires. This parameter optimization ensures that the sacrifice rib wears actively enough to prevent uneven wear, while maintaining sufficient road contact pressure at the outer edge to avoid accelerating uneven wear through excessive wear or structural degradation.
Data Source
AI summary
The offset amount that a sacrificial rib road contact surface is recessed to the inner side of a tire with regards to a shoulder rib road contact surface is equal to 0, and a circumferential fine groove is provided such that the opening side thereof is located on the inner side when the tire is filled to a proper internal pressure. The dimension Ws in the tire width direction of the shoulder rib road contact surface and the dimension Wa in the tire width direction of the sacrificial rib road contact surface are set such that 0.10≦Wa/Ws≦0.2. The dimension Wb in the tire width direction of the sacrificial rib road contact surface when the groove depth of the circumferential main grooves has worn 20% is set in a range such that 0.25≦Wb/Ws≦0.30.