PCB Terminal Fixation Leg and Press-Fit Hole Design
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Solution Overview
Problem
Conventional printed circuit boards with terminals face issues of terminal displacement due to thermal expansion differences, solder cracking, and potential damage to inner layer circuits when using synthetic resin seats for retention, leading to increased component count and manufacturing complexity.
Innovation Solution
A printed circuit board design where the terminal's soldering section is inserted without press-fitting into a through-hole, using a fixation leg that press-fits into a press-fit hole on the board, with plated inner through-hole surfaces and unplated press-fit hole surfaces, eliminating the need for a synthetic resin seat and ensuring reliable connection and reduced component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a synthetic resin seat is used to retain the terminal, then the terminal can be positioned and retained on the printed circuit board, but the terminals and the printed circuit board are relatively displaced based on the difference in linear expansion coefficient, possibly causing solder cracking
Solution Approach 1:
The invention extracts and eliminates the synthetic resin seat from the structure, allowing the terminal to be retained directly by the printed circuit board through a press-fit hole. This removes the source of thermal expansion mismatch that causes solder cracking, while maintaining retention functionality through the press-fit mechanism.
Solution Approach 2:
The invention segments the hole structure into two distinct types: a through-hole for the soldering section and a press-fit hole for the fixation leg. This segmentation allows each hole to serve its specific function without the need for a separate synthetic resin seat, resolving the thermal expansion issue while maintaining retention.
2Reliability
If a synthetic resin seat is used to retain the terminal, then the terminal can be positioned and retained on the printed circuit board, but there is a need for a separate component, that is, the seat, which needs to be retained using a jig at the time of soldering, and thus an increase in the number of constituent components and complication of the manufacturing processing are inevitable
Solution Approach 1:
The invention merges the retention function previously performed by a separate synthetic resin seat into the printed circuit board itself through the press-fit hole structure. The fixation leg of the terminal directly engages with the press-fit hole in the board, eliminating the need for a separate seat component and simplifying the overall structure.
Solution Approach 2:
The printed circuit board is given multiple functions: it serves as both the mounting substrate and the retention mechanism through the press-fit hole. The fixation leg's press-fit engagement with the board integrates the retention function into the board itself, eliminating the need for separate retention components.
3Ease of operation
If the soldering sections are press-fitted into the through-holes of the printed circuit board, then the terminals stand on their own on the printed circuit board, but an inner layer circuit of the printed circuit board may be damaged, causing a defect such as disconnection of wires of the inner layer circuit
Solution Approach 1:
The invention segments the hole structure into two distinct types: a through-hole for the soldering section and a press-fit hole for the fixation leg. This segmentation allows the fixation leg to provide positioning and retention forces through the press-fit hole without damaging the inner layer circuit, while the soldering section remains undamaged in the through-hole for reliable soldering.
4Ease of operation
If the soldering sections are press-fitted into the through-holes of the printed circuit board, then the terminals stand on their own on the printed circuit board, but it may be difficult to ensure connection reliability due to the detachment of plating from the inner surfaces of the through-holes or a reduction in the amount of solder filling
Solution Approach 1:
The invention segments the hole structure into two distinct types: a through-hole for the soldering section and a press-fit hole for the fixation leg. This segmentation ensures that the soldering section can be properly soldered in the through-hole without damage, while the fixation leg provides positioning and retention forces through the press-fit hole, thereby ensuring both positioning ease and connection reliability.
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 enhances connection reliability by preventing solder cracking and inner layer damage, reduces component count and manufacturing complexity, and allows for precise positioning and retention of terminals, improving the stability and reliability of the terminal-to-board connection.
Implementation Method 1
an inner circumferential surface of the through hole is plated
Implementation Method 2
the fixation log of the terminal being press-fitted into the press-fit hole of the printed circuit board
Implementation Method 3
the soldering section of the terminal is inserted, without being press-fitted, into a through-hole of the printed circuit board, and is fixed by soldering
Data Source
AI summary
A printed circuit board with a terminal having a novel structure that enables terminals to stand on their own on the printed circuit board without using a seat, while reducing or eliminating damage to through-hole plating or an inner layer circuit. A printed circuit board with a terminal includes a terminal having soldering sections that are inserted, without being press-fitted, into through-holes of a printed circuit board and are fixed by soldering. The terminal has a fixation leg and the printed circuit board has a press-fit hole, the terminal is positioned and retained on the printed circuit board by the fixation leg of the terminal being press-fitted into the press-fit hole of the printed circuit board, and an inner circumferential surfaces of the through-holes are provided with plating, whereas an inner circumferential surface of the press-fit hole is not provided with the plating.