Shoulder Groove Chamfering in Tyres for Heel-Toe Wear Control
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Solution Overview
Problem
Pneumatic tires experience uneven wear, particularly heel-and-toe wear, due to slippery block edges contacting the ground during vehicle operation, leading to premature wear.
Innovation Solution
The tire design incorporates axially spaced tread edges with first shoulder land portions featuring continuous circumferential grooves and chamfered groove walls that extend beyond the tread edge, providing uniform contact pressure and reducing wear, along with non-chamfered groove edges for enhanced friction and braking performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the block edges of shoulder blocks contact the ground directly, then the tyre provides good friction and braking performance, but the block edges wear prematurely due to slippery contact (heel-and-toe wear)
Solution Approach 1:
The groove walls are given different local qualities: chamfer portions with inclined surfaces in the contact area to distribute pressure and reduce wear, and non-chamfered portions with vertical edges to maintain friction. This local differentiation allows the tyre to simultaneously achieve reduced heel-and-toe wear and maintained braking performance.
Solution Approach 2:
The chamfer portions are pre-formed on the groove walls before the tyre contacts the ground. These inclined surfaces prepare the contact area to distribute ground pressure evenly from the start, preventing the development of heel-and-toe wear patterns while maintaining adequate friction for braking.
2Duration of action of stationary object
If chamfer portions are added to the groove walls, then wear is reduced, but the device complexity increases
Solution Approach 1:
Rather than fundamentally changing the tread pattern design, the invention applies a localized modification (chamfer portions) only to specific areas of the groove walls. This minimizes the increase in overall device complexity while achieving the wear reduction benefit.
3Duration of action of stationary object
If the groove walls are made smooth to reduce wear, then friction decreases, but if made rough to increase friction, then wear increases
Solution Approach 1:
The groove walls are differentiated into two zones with different surface characteristics: chamfer portions with smoother inclined surfaces for pressure distribution and wear reduction, and non-chamfered portions with rougher vertical edges for maintaining friction. This local quality differentiation resolves the contradiction between reducing wear and maintaining friction force.
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 effectively prevents uneven wear, improves steering stability, and maintains braking performance on both dry and wet roads by distributing ground pressure evenly and increasing frictional force.
Implementation Method 1
the pair of first chamfer portions has a chamfer width reducing outwardly in the tyre axial direction and terminates at a first location beyond the first tread edge
Implementation Method 2
the first shoulder lateral grooves comprising a pair of non-chamfered groove edges that extends outwardly in the tyre axial direction from the first location of the pair of first groove walls
Data Source
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AI summary
A tyre includes a tread portion including first and second tread edges, a first shoulder land portion including the first tread edge, and a first shoulder circumferential groove located inwardly in a tyre axial direction of and adjacent to the first shoulder land portion and extending continuously in a tyre circumferential direction. The first shoulder land portion is provided with a plurality of first shoulder lateral grooves extending from the first shoulder circumferential groove across the first tread edge, each of the plurality of first shoulder lateral grooves has a pair of first groove walls, and the pair of first groove walls is provided with a pair of first chamfer portions that extends from the first shoulder circumferential groove to a first location beyond the first tread edge.