Terminal Contact Structure With Reduced Press-Fit Plating Scrape
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Solution Overview
Problem
In conventional terminal units, the resilient contact piece of the tubular connecting portion rubs against the columnar connecting portion during press-fitting, leading to scraping of plating and increased contact resistance due to repeated insertion and withdrawal of the first terminal into and from the second terminal.
Innovation Solution
The terminal unit incorporates a first terminal with a columnar connecting portion featuring a sliding resistance reducing portion extending from the tip surface toward a first side contact point, and a second terminal with a tubular connecting portion that is resiliently deformable in a diameter expanding direction, allowing the columnar connecting portion to be press-fit into the tubular connecting portion with reduced sliding resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the resilient contact piece rubs against the columnar connecting portion during press-fitting, then the first terminal can be assembled with the second terminal, but the plating on both connecting portions is scraped leading to increased contact resistance
Solution Approach 1:
A resin layer is formed on the outer peripheral surface of the columnar connecting portion to serve as an intermediary between the resilient contact piece and the metal plating. This resin coating prevents direct contact and friction between the metal surfaces during assembly, thereby preventing plating scraping while still allowing the press-fitting operation to proceed smoothly
2Adaptability or versatility
If repeated insertion and withdrawal of the first terminal occurs, then the terminal unit can be used multiple times, but the plating scraping accumulates leading to higher contact resistance
Solution Approach 1:
The resin layer is pre-formed on the columnar connecting portion before any assembly operations take place. This preliminary protective coating is designed to withstand multiple insertion and withdrawal cycles, preventing cumulative plating damage that would otherwise occur with repeated use of the terminal unit
3Reliability
If the columnar connecting portion is press-fit into the tubular connecting portion, then electrical connection is established, but friction and sliding resistance occur during the process
Solution Approach 1:
The surface properties of the columnar connecting portion are changed by coating it with resin material. This parameter change in surface composition reduces the coefficient of friction between the columnar connecting portion and the resilient contact piece, thereby reducing sliding resistance during press-fitting while maintaining the electrical connection function
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 scraping of plating on both the columnar and tubular connecting portions, thereby reducing contact resistance and preventing plating damage during the press-fitting process.
Implementation Method 1
the resilient contact piece contacted by the columnar connecting portion is expanded in diameter and deformed against a resilient restoring force and the columnar connecting portion is allowed to enter the inside of the tubular connecting portion
Implementation Method 2
By this resilient restoring force of the resilient contact piece, a contact point portion provided on an end part of the resilient contact piece is pressed against the columnar connecting portion of the first terminal and the first terminal and second terminal are held in contact
Data Source
AI summary
A terminal unit includes a first terminal including a columnar connecting portion, a first side contact point provided on the columnar connecting portion and a sliding resistance reducing portion extending from a tip surface of the columnar connecting portion toward the first side contact point, and a second terminal including a tubular connecting portion and a second side contact point provided on the tubular connecting portion. The columnar connecting portion is assembled with the tubular connecting portion by being press-fit into the tubular connecting portion. The sliding resistance reducing portion avoids direct sliding contact between the outer peripheral surface of the columnar connecting portion and the second side contact point to reduce sliding resistance of the columnar connecting portion against the second side contact point until the sliding resistance reducing portion moves beyond the second side contact point in a press-fitting direction.