Lug Bar Flush Overlay Edge Forging to Reduce Stress Concentration
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Solution Overview
Problem
Frequent repairs of track shoes due to worn-out grouser portions lead to increased downtime of work machines, as existing lug bars lack durability and are prone to degradation from stress concentration at overlay edges.
Innovation Solution
A lug bar with a flush overlay edge, made of a wear-resistant material and including hard particles, is designed to enhance durability by preventing stress concentration and particle fallout, featuring a forged surface and protrusions to secure the overlay to the base.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an overlay is formed on the base by overlaying welding to improve wear resistance, then the durability of the lug bar is improved, but a step is formed at the overlay edge portion which causes stress concentration and degradation in durability
Solution Approach 1:
The patent changes the physical state and geometry of the overlay edge portion through forging processing. The forging process plastically deforms the overlay material to eliminate the step and create a flush surface, transforming the edge geometry from stepped to continuous, thereby eliminating stress concentration points while preserving the wear-resistant overlay structure.
Solution Approach 2:
The patent performs forging processing on the overlay edge portion before the lug bar is installed and subjected to service loads. This preliminary action of eliminating the step beforehand prevents stress concentration from developing during operation, thereby maintaining durability without compromising the wear resistance provided by the overlay.
2Reliability
If hard particles are dispersed in the overlay matrix to enhance wear resistance, then the durability is improved, but the hard particles may protrude from the surface and fall off during use
Solution Approach 1:
The patent changes the positional parameters of hard particles within the overlay structure through forging processing. The plastic deformation caused by forging redistributes and embeds protruding hard particles into the overlay matrix, transforming their position from surface-protruding to embedded, thereby preventing particle fallout while maintaining the wear-resistant function.
Solution Approach 2:
The patent converts the potentially harmful effect of protruding hard particles (which could fall off) into a beneficial embedded structure through forging. The forging process uses controlled plastic deformation to embed the particles, transforming what would be a defect into a stable, integrated component that maintains wear resistance without particle loss.
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 improved lug bar significantly increases durability by eliminating stress concentration and particle loss, reducing the frequency of repairs and extending the lifespan of track shoes.
Implementation Method 1
The overlay can be formed on the surface of the base by overlaying welding or other techniques.
Implementation Method 2
In the overlay edge portion, the exposed region and a surface of the overlay are flush with each other to form a forged surface.
Data Source
AI summary
The lug bar includes a base, having a bar shape and made of a first metal, and an overlay, extending along the longitudinal direction of the base to cover a covered region as a part of the outer peripheral surface of the base. In an overlay edge portion corresponding to a boundary between the covered region and an exposed region other than the covered region of the surface of the base, the exposed region and the surface of the overlay are flush with each other to form a forged surface.