Press-Fit Terminal Geometry for Lower Board Insertion Damage
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Solution Overview
Problem
Press-fit terminals experience increased insertion force when silver plating is applied to the through-hole of a board without a lubricant, leading to potential damage on the board.
Innovation Solution
A press-fit terminal with a tapered tip portion and a resiliently deformable press-fit portion, featuring first and second parts that are shifted and arranged differently in the circumferential direction, allowing for controlled contact with the board's inner surface to manage insertion force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the insertion force of the press-fit terminal increases, then the contact load is improved, but damage on the board increases
Solution Approach 1:
By segmenting the contact surfaces circumferentially, the insertion force is distributed across multiple contact points rather than concentrated at a single location. This prevents localized stress concentration that could cause board damage while still achieving the required overall contact load.
Solution Approach 2:
Different parts of the press-fit portion have different contact characteristics - the first, second, and third parts engage the through-hole at different stages. This creates local variations in contact quality that allow gentle initial engagement followed by progressive load application, protecting the board from excessive 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 solution effectively suppresses board damage while maintaining a necessary contact load by distributing the insertion force and reducing peak forces during the insertion process.
Implementation Method 1
the press-fit portion being resiliently deformable in a direction orthogonal to the axial direction
Data Source
AI summary
A press-fit terminal includes a press-fit portion resiliently deformable in a direction orthogonal to an axial direction. The press-fit portion includes a first part located further away from an axial center than other parts of an outer periphery of a first cross-section on a part of the outer periphery of the first cross-section along the direction orthogonal to the axial direction. The press-fit portion includes a second part located further away from the axial center than other parts of an outer periphery of a second cross-section closer to a tip portion than the first cross-section on a part of the outer periphery of the second cross-section along the direction orthogonal to the axial direction. The first part and the second part are shifted and arranged at positions different in a circumferential direction when the press-fit portion is viewed from the axial direction.