Linkage Recess Design for Weld Fatigue Reduction
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Solution Overview
Problem
Welded linkages in work machines suffer from fatigue cracks and fractures due to residual tensile stresses and stress concentration, leading to reduced reliability and increased downtime, as existing post-welding techniques have limited efficacy in improving fatigue characteristics.
Innovation Solution
Incorporating a recess proximate to the weld in the linkage's linking section to redirect and absorb stresses, allowing the linkage to flex and reduce strain on the weld, without altering the overall geometry, and machining this recess with specific dimensions to optimize stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If welded joints are used to connect linkage components, then the linkage can be assembled from separate pieces, but residual tensile stresses and stress concentration occur at the weld contact area, leading to fatigue cracks and reduced reliability
Solution Approach 1:
The patent applies preliminary action by machining recesses into the linkage components before welding. These recesses are strategically positioned to redirect stress away from the weld contact area, preventing stress concentration before it can cause fatigue cracks during service.
Solution Approach 2:
The patent changes the geometric parameters of the linkage components by introducing recesses with specific dimensions and positions. This modifies the stress distribution pattern in the welded joint, reducing peak stresses at the weld contact area and improving fatigue resistance.
2Reliability
If post-welding impact treatment is applied to reduce residual stress, then fatigue characteristics can be improved, but the treatment has limited efficacy and cannot fully eliminate weld fatigue
Solution Approach 1:
The patent performs stress reduction through recess geometry design before welding occurs, rather than relying on post-welding treatments. This preliminary structural modification is more effective at preventing fatigue cracks than subsequent impact treatments.
Solution Approach 2:
The patent fundamentally changes the approach from post-welding parameter adjustment (impact treatment) to pre-welding geometric parameter optimization (recess design). This creates a more effective stress distribution that genuinely improves fatigue characteristics.
Data Source
AI summary
A work machine includes a frame, a traction system supporting the frame, an arm assembly having a first end and a second end, the first end connected to the frame, an implement connected to the second end, and a linkage connecting the implement to the second end of the arm assembly. The linkage includes a pin-supporting section configured to accept a pin and a linking section attached to the pin-supporting section by a weld. The linking section includes a recess proximate to the weld.