Pneumatic Tire Shoulder Blocks for Mud Traction
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Solution Overview
Problem
Pneumatic tires with lug grooves designed for muddy and snowy conditions face challenges in achieving both sufficient traction and mud discharge, particularly when encountering deep mud, due to insufficient shear force and mud compaction.
Innovation Solution
The tire features an annular-shaped tread with recessed portions on the shoulder blocks, a narrow width bent portion in the lug grooves, and a stepwise protruding and recessed portion design, which enhances mud engagement and compaction, ensuring excellent traction and balanced mud discharge performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the groove width of the lug groove increases toward the outer side in the tire width direction, then the discharging performance of mud and the like is improved, but the traction properties occurring due to shear force with regard to mud and the like compacting in the lug groove become insufficient
Solution Approach 1:
The lug groove is divided into a first lug groove portion (inner side) and a second lug groove portion (outer side), with each serving different functions. The first portion maintains narrow width for mud compaction and traction, while the second portion widens for mud discharge, resolving the contradiction between traction and discharge performance
Solution Approach 2:
Different sections of the lug groove are given different local characteristics: the inner section has narrow width and closed periphery for compaction, while the outer section has wide opening for discharge. This localized differentiation allows simultaneous achievement of both traction and discharge functions
2Force
If the blocks extend to the inner side in the tire radial direction to enhance traction properties, then the traction performance is improved, but the mud discharge capability may be compromised
Solution Approach 1:
The invention extends the block in the radial direction (inner side) for traction while using the circumferential dimension (lug groove extending to sidewall) for mud discharge. This multi-dimensional approach allows both functions to coexist without compromising either
3Reliability
If the groove area or groove depth is increased to improve mud discharge, then the discharging performance is enhanced, but the traction performance may be reduced
Solution Approach 1:
The lug groove is segmented into functional zones: the first portion (inner side) with smaller cross-sectional area for traction through compaction, and the second portion (outer side) with larger opening for discharge, achieving both functions without trade-off
Data Source
AI summary
A pneumatic tire includes: a main groove extending in a tire circumferential direction disposed on a shoulder region of a tread portion; lug grooves extending from the main groove toward an outer side and reaching a side wall portion; and blocks demarcated by the main groove and lug grooves. An edge on an innermost side in a tire radial direction of the blocks is positioned more on an outer side in the tire radial direction than a tire maximum width position, and a ratio of an orthogonal distance from a ground contact end position to the edge on an innermost side in the tire radial direction of the blocks is 0.2 or more. Recessed portions each having a closed periphery are provided in a side region more on an outer side in a tire width direction than the ground contact end of the blocks.