Connector Terminal Fitting Press-in Hole Clearance Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing connectors for printed circuit boards risk damaging the plated surfaces of terminal fittings due to abrasion against the inner surfaces of press-in holes during insertion, despite attempts to define clearance through cross-sectional size selection, as tolerances and displacements can still lead to contact.
Innovation Solution
The connector design features press-in holes with a passage area at a widthwise intermediate part that is shaped to maintain a distance from the touching section, with obliquely aligned ridge surfaces and beveled corners on the terminal fitting to prevent abrasion, ensuring a constant clearance and alignment during insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the cross-sectional size of the terminal fitting is reduced to fit the press-in hole, then the terminal fitting can be inserted into the housing, but the inner surface of the press-in hole will abrade against the plated surface of the touching section and damage it
Solution Approach 1:
The press-in hole is designed with a three-dimensional tapered structure rather than a simple cylindrical shape. The inner surface includes a tapered portion that slopes upward from the bottom, creating a dimensional variation that provides clearance between the touching section and the press-in hole wall during insertion, thereby preventing abrasion damage.
Solution Approach 2:
The tapered portion of the press-in hole is pre-formed to create clearance before the touching section makes contact with the mating terminal. This preliminary geometric configuration ensures that the touching section passes through without rubbing against the press-in hole surface, preventing damage before it can occur.
2Object-affected harmful factors
If a clearance is defined between the touching section and the inner surface of the press-in hole, then abrasion can be prevented, but alignment accuracy may be compromised due to tolerances and displacements
Solution Approach 1:
The inner surface of the press-in hole is segmented into different functional zones: a tapered portion that provides clearance and prevents abrasion, and a straight portion at the top that provides positioning and alignment. This segmentation allows each zone to fulfill its specific function independently.
Solution Approach 2:
Different portions of the press-in hole inner surface have different geometric properties tailored to local requirements. The lower tapered portion provides clearance for abrasion prevention, while the upper straight portion provides precise alignment, with each local region optimized for its specific function.
3Reliability
If the touching section is held pressingly in the housing after insertion, then connection reliability is improved, but the touching section may contact and abrade against the inner surface of the press-in hole
Solution Approach 1:
The press-in hole utilizes a three-dimensional tapered configuration where the clearance is maintained in the radial dimension during insertion, preventing abrasion. After insertion, the terminal fitting is held pressingly in the axial dimension to ensure connection reliability, with the tapered geometry ensuring that pressing force does not cause lateral contact between the touching section and press-in hole surface.
Data Source
AI summary
A connector has terminal fittings (20) with a touching section (41) to be held in contact with a mating terminal (30) and a housing (10) formed with press-in holes (14, 14A), into which the terminal fittings (20) are pressed. The terminal fittings (20) are pressingly held in the housing (10) after the touching sections (41) pass through the press-in holes (14, 14A). A part of the inner surface of each press-in hole (14, 14A) of the housing (10) corresponding to a passage area of the touching section (41) is shaped to be gradually distanced from the passage area towards an apex (62, 62A) at a widthwise middle part (65) of the passage area. Accordingly, mutual abrasion of the touching section (41) and the inner surface of the press-in hole (14, 14A) can be avoided when the touching section (41) passes through the press-in hole (14, 14A).