Welding Electrode Sliding Member Structure for Thermal Expansion Wear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electrical resistance welding electrodes where a guide pin and sliding member are integrated by injection molding, the uniform thickness of the sliding member leads to excessive expansion and wear, causing misalignment and reduced welding accuracy due to increased inclination of the guide pin.
Innovation Solution
The integration of a guide pin and sliding member by insert molding, with a thin-wall deformable portion in the extended portion of the sliding member, reduces wear by distributing the thermal expansion force, maintaining normal sliding and preventing excessive inclination of the guide pin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sliding member is made with uniform thickness to maintain coupling rigidity, then the coupling rigidity between guide pin and sliding member is improved, but the sliding wear amount increases and welding accuracy deteriorates due to thermal expansion
Solution Approach 1:
The sliding member is designed with non-uniform thickness: the inserted portion (near guide pin) has greater thickness for high coupling rigidity, while the extended portion has reduced thickness to minimize thermal expansion and wear. This local differentiation resolves the contradiction by optimizing each region's thickness according to its specific functional requirements.
Solution Approach 2:
The sliding member is segmented into functionally distinct regions: the inserted portion for strong coupling with the guide pin, and the extended portion for guiding with reduced wear. This segmentation allows each part to be optimized independently, maintaining rigidity where needed while reducing expansion and wear in the extended region.
2Strength
If the sliding member thickness is increased to maintain coupling rigidity, then the coupling rigidity is improved, but the pressing force on the guide hole inner face increases during thermal expansion causing excessive wear
Solution Approach 1:
The sliding member employs local quality differentiation with thicker design at the inserted portion to ensure coupling rigidity, and thinner design at the extended portion to reduce thermal expansion and pressing force on the guide hole, thereby improving wear resistance without compromising overall rigidity.
Solution Approach 2:
The thickness parameter of the sliding member is changed along its length rather than being uniform. The inserted portion maintains sufficient thickness for rigidity, while the extended portion has reduced thickness to minimize thermal expansion effects and resulting wear on the guide hole surface.
3Reliability
If the sliding member thickness is reduced to minimize thermal expansion, then the sliding wear amount is reduced, but the coupling rigidity between guide pin and sliding member deteriorates
Solution Approach 1:
The sliding member is designed with locally differentiated thickness to resolve the contradiction: the inserted portion maintains sufficient thickness for coupling rigidity, while the extended portion has reduced thickness to minimize thermal expansion and wear, achieving both rigidity and wear resistance in appropriate locations.
4Ease of manufacture
If uniform thickness is used throughout the sliding member, then manufacturing is simplified, but excessive gap forms between sliding member and guide hole after thermal contraction reducing welding accuracy
Solution Approach 1:
The sliding member uses local quality differentiation with varying thickness along its length. This can be implemented through injection molding techniques such as variable thickness mold design or two-shot molding, balancing manufacturing feasibility with the need to minimize thermal expansion gaps and maintain welding accuracy.
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
This configuration significantly reduces the sliding wear amount in the extended portion, maintaining normal sliding and preventing excessive inclination of the guide pin, thereby improving welding accuracy and reliability.
Implementation Method 1
when the extended portion is heated, a surface of the thin-walled deformation portion bulges toward an inside of the air passage due to an expansion force in a circumferential direction of a non-thin-wall deformable portion
Implementation Method 2
an air passage of cooling air flowing into the guide hole from a vent hole of the main body of the electrical resistance welding electrode is configured by forming a flat portion on an outer peripheral face of the sliding member
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
A guide pin made of a heat-resistant hard material and a sliding member made of an insulating synthetic resin material are integrated. An inserted portion and an extended portion are provided in the sliding member. The thickness of the extended portion is set to be thinner than the thickness of the inserted portion. An air passage is formed in the extended portion thereby forming a thin-wall deformable portion. The surface of the thin-wall deformable portion is configured to bulge toward the air passage side when the extended portion is thermally expanded.