Press-fit Terminal Curved Corner Radius for Insertion Force
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Solution Overview
Problem
Press-fit terminals face challenges in ensuring connection reliability while minimizing insertion force, particularly in the branch portion where high strain can occur due to excessive load applied to the elastic contact portions.
Innovation Solution
The press-fit terminal design includes deformable portions with curved surfaces having a greater radius of curvature than the distal end portion, allowing for easier insertion with reduced deformation and increased rigidity, ensuring reliable contact with the through hole's inner wall without excessive strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the load applied by the elastic contact portions to the inner wall of the through hole is increased to ensure connection reliability, then the connection reliability is improved, but great strain is caused in the terminal particularly in the branch portion
Solution Approach 1:
The patent applies different radius of curvature values to different portions of the deformable portions. The outer deformable portion side corner portions have a first radius of curvature that is greater than the second radius of curvature of the distal end portion side corner portions. This local differentiation allows the outer portions to be more easily deformed for insertion while the distal end portions maintain higher rigidity for reliable contact, thereby resolving the contradiction between connection reliability and strain reduction.
2Force
If the radius of curvature of the deformable portion side corner portions is increased to reduce insertion force, then the insertion force is reduced, but the rigidity of the distal end portion may be compromised
Solution Approach 1:
The patent implements local quality by assigning different radius of curvature values to different sections. The outer deformable portion side corner portions have a larger first radius of curvature that facilitates easier deformation and reduces insertion force. Meanwhile, the distal end portion side corner portions have a smaller second radius of curvature that maintains structural rigidity. This spatial differentiation of geometric properties resolves the contradiction between reducing insertion force and maintaining distal end rigidity.
3Strength
If the cross-sectional area of the distal end portion is increased to maintain rigidity and holding force, then the rigidity is improved, but the insertion force may increase
Solution Approach 1:
The patent resolves this contradiction by locally optimizing the radius of curvature at different positions. The distal end portion side corner portions have a smaller second radius of curvature that provides the necessary rigidity and holding force. The outer deformable portion side corner portions have a larger first radius of curvature that reduces insertion force. This localized geometric optimization allows the structure to simultaneously achieve both rigidity where needed and ease of insertion where deformation is required.
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 design reduces the insertion force required while maintaining connection reliability by minimizing deformation and strain, ensuring effective electrical contact and holding force.
Implementation Method 1
The deformable portions are to be contacted with an inner wall of the through hole and elastically deformed
Data Source
AI summary
A press-fit terminal inserted into through hole of a circuit board along insertion direction includes a base portion extending in insertion direction, distal end portion, and two deformable portions. The distal end portion is on a front side to base portion in insertion direction and includes distal end portion side corner portions. The two deformable portions connect base portion and distal end portion and are contacted with an inner wall of through hole and elastically deformed. The two deformable portions include deformable portion side corner portions and deformable portion side corner portions include outer deformable portion side corner portions on outer side in direction crossing insertion direction. The two deformable portions include easy deformable portions, in portions having outer deformable portion side corner portions with curved surfaces whose radius of curvature RL is greater than a radius of curvature RS of curved surfaces of distal end portion side corner portions.