Electrical Connector Housing Locking for Reflow Contact Reliability
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Solution Overview
Problem
The existing electrical connectors experience a reduction in holding force due to stress relaxation during the reflow soldering process, leading to unstable contact reliability, as the frictional force generated by the press-fitting surface is compromised by heat, causing the housing to shift within the shell.
Innovation Solution
Incorporating engagement protrusions on both the housing and the shell, where the housing's engagement protrusion locks into the shell's engagement protrusion, maintaining the holding force even after reflow soldering, thereby preventing the housing from shifting and ensuring contact reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the housing is held in the shell by frictional force on the press-fitting surface, then the housing can be fixed in position, but the holding force is drastically reduced after reflow soldering due to stress relaxation
Solution Approach 1:
The housing is divided into two functional parts: a press-fitting portion that provides initial positioning and friction-based holding, and a protruding portion that extends beyond the shell to provide additional mechanical engagement. This segmentation allows the housing to benefit from both frictional holding during assembly and enhanced mechanical interlocking to maintain position after stress relaxation occurs during reflow soldering.
Solution Approach 2:
The protruding portion of the housing is designed to engage with the shell in advance, creating a mechanical constraint that prevents the housing from shifting toward the base side. This preliminary structural arrangement counteracts the anticipated loss of holding force due to stress relaxation during reflow soldering, ensuring contact reliability is maintained throughout the manufacturing process and product lifecycle.
2Stability of the object's composition
If the housing is press-fitted into the shell, then the housing can be positioned stably, but stress relaxation during reflow soldering causes the housing to shift
Solution Approach 1:
The housing structure is segmented into a press-fitting portion for initial stable positioning and a protruding portion that extends beyond the shell. This dual-structure design ensures that even when stress relaxation occurs during reflow soldering, the protruding portion maintains mechanical engagement with the shell, preventing housing shift and preserving contact reliability.
Solution Approach 2:
The protruding portion of the housing acts as a pre-designed mechanical cushion against position instability. By extending beyond the shell and engaging with it, this structure provides a backup holding mechanism that compensates for the anticipated loss of frictional holding force during reflow soldering, thereby cushioning against potential housing shift and maintaining contact 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
The engagement mechanism between the housing and shell maintains the holding force during reflow soldering, ensuring stable contact reliability and preventing the housing from shifting, thus enhancing the electrical connector's performance.
Implementation Method 1
the engagement protrusion of the housing is engaged with the engagement protrusion of the shell in a state that the housing is contained in the containing portion of the shell, and thereby the housing is locked in the containing portion of the shell
Implementation Method 2
the above-mentioned shifting of the housing is prevented by holding force provided by frictional force on a press-fitting surface between the housing 11 and the shell 12, which is generated by press-fitting the housing 11 into the shell 12
Implementation Method 3
when a reflow soldering process is performed for mounting the electrical connector onto a circuit board, stress relaxation of the housing 11 occurs due to heat generated during the reflow soldering process
Data Source
AI summary
An electrical connector contains a contact pin, a cylindrical insulating housing for containing the contact pin therein, and a metal shell for holding the contact pin and the housing. The shell includes a containing portion for containing the housing therein and an engagement protrusion protruding from an inner surface of the containing portion toward an inner side. An engagement protrusion of the housing is engaged with the engagement protrusion of the shell in a state that the housing is contained in the containing portion of the shell, and thereby the housing is locked in the containing portion of the shell.