Press-fit Terminal Substrate With Flexible Layer
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Solution Overview
Problem
Conventional electronic devices with press-fit terminals face issues of increased load on the substrate during press-fitting, leading to potential damage and a decrease in holding force due to the need for greater deformation of the terminal, which can result in plastic deformation and reduced contact reaction force.
Innovation Solution
The electronic device incorporates a substrate with a core layer and a flexible layer, where the flexible layer is positioned closer to the surface and has a lower elastic modulus than the core layer, allowing for elastic deformation to absorb the load during press-fitting, while the core layer maintains the contact with the press-fit terminal, reducing substrate deformation and holding force loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a press-fit terminal is press-fitted into a through hole of a substrate without using a jig, then the press-fitting process is simpler, but the load applied to the substrate increases significantly causing damage
Solution Approach 1:
The patent introduces a jig as an intermediary tool during the press-fitting process. The jig distributes the pressing load over a larger area of the substrate, preventing localized stress concentration and damage. The jig acts as a mediator between the press-fit terminal and the substrate, enabling simpler direct press-fitting while protecting the substrate from excessive load.
2Strength
If a jig is used to press-fit the press-fit terminal, then the load on the substrate is reduced, but the width of the terminal must be narrower than the jig's internal diameter requiring greater terminal deformation
Solution Approach 1:
The patent modifies the physical parameters of the press-fit terminal, specifically making it elastically deformable with controlled plastic deformation characteristics. The terminal is designed with material properties and geometric features that allow it to deform elastically during press-fitting and maintain contact pressure, while limiting plastic deformation to prevent excessive width reduction. This parameter change enables the terminal to fit through the jig's internal diameter while maintaining adequate contact force.
3Ease of operation
If the press-fit terminal undergoes greater deformation to fit through the jig, then it can be inserted, but plastic deformation occurs reducing the contact reaction force and holding force
Solution Approach 1:
The patent changes the material parameters of the press-fit terminal by selecting materials with specific elastic modulus and yield strength characteristics. The terminal is designed to undergo primarily elastic deformation rather than plastic deformation during insertion. By controlling the material parameters, the terminal maintains its contact reaction force and holding force after insertion, while still being able to pass through the jig's internal diameter.
Solution Approach 2:
The patent introduces dynamic characteristics to the press-fit terminal by making it elastically deformable. The terminal dynamically adjusts its shape during insertion and maintains a reactive contact force through elastic recovery. This dynamic behavior allows the terminal to flex during insertion through the jig while automatically maintaining contact pressure and holding force through elastic rebound, rather than relying on permanent plastic deformation.
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 effectively suppresses the increase in load on the substrate during press-fitting and maintains a stable holding force between the press-fit terminal and the substrate, preventing deformation and breakage of the terminal and substrate.
Implementation Method 1
The flexible layer can be easily deformed by load from the press-fit terminal. Thus, an increase in load applied to the substrate during the press-fitting of the press-fit terminal can be suppressed by the deformation of the flexible layer.
Implementation Method 2
The press-fit terminal is connected to the electrode by a reaction force due to the elastic deformation of the press-fit terminal.
Data Source
AI summary
An electronic device includes a substrate, and a press-fit terminal. The substrate includes a first surface, a second surface opposite to the first surface in a thickness direction of the substrate, a through hole, and an electrode formed in the first surface, the second surface, and a wall of the through hole. The press-fit terminal is fit into the through hole from the first surface while being elastically deformed. The press-fit terminal is connected to the electrode by a reaction force due to the elastic deformation of the press-fit terminal. The substrate includes (i) a core layer that is overlapped, in the thickness direction, with a contact portion of the electrode with the press-fit terminal, and (ii) a flexible layer that is at a position closer to the first surface than the core layer is to. The flexible layer has a lower elastic modulus than the core layer.