Junction Box Opening Width Control via Ribs and Projections
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Solution Overview
Problem
Conventional electrical junction boxes with thin, tall primary housings made of synthetic resin often experience wall warpage, which narrows the opening and complicates the insertion and mounting of circuit board assemblies and secondary housings, potentially interfering with components and deteriorating solder connections.
Innovation Solution
The electrical junction box features a primary housing with projections and ribs to maintain and widen the opening, preventing inward warpage and ensuring smooth insertion of the circuit board assembly and secondary housing, while ribs and protuberances enhance structural strength and prevent deformation, ensuring reliable electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the primary housing is made thin and tall to be mounted in a narrow space, then the mounting space efficiency is improved, but the wall may warp inwardly causing the opening to narrow and making it difficult to mount components
Solution Approach 1:
The circuit board assembly is inserted into the primary housing before the secondary housing is installed. This preliminary action allows the circuit board to be securely positioned and connected before the opening is closed by the secondary housing, solving the problem of difficult component mounting caused by wall warpage in thin-tall housings
Solution Approach 2:
The housing is divided into two separate parts: a primary housing that accommodates the circuit board assembly and a secondary housing that covers the opening. This segmentation allows the circuit board to be installed in the primary housing first, then the secondary housing is attached to complete the assembly, overcoming the mounting difficulties caused by wall deformation
2Device complexity
If the wall of the primary housing is pressed inwardly from without during mounting, then the housing structure is simplified, but the terminals and other components may be interfered with and solder connection may deteriorate
Solution Approach 1:
The circuit board assembly with terminals is inserted and positioned in the primary housing before the secondary housing is installed. This ensures that the terminals are already in their correct positions and connections are made before any external pressing occurs during final assembly, protecting solder connection reliability
Solution Approach 2:
The circuit board assembly is nested inside the primary housing, which is then inserted into the secondary housing. This nested structure protects the terminals and components from external forces during mounting, preventing interference with solder connections while maintaining a simple overall housing structure
Data Source
AI summary
An electrical junction box, which is assembled by first inserting a circuit board assembly into a primary housing via an opening of the primary housing, and after that inserting a secondary housing into the primary housing, includes a connector block that has a projection that widens the opening that has been narrowed. A plurality of ribs are formed on front and rear walls of the thin primary housing from the side of the opening in an insertion direction of the circuit board assembly. A concave groove formed between a pair of the projections engages with the rib of the front wall. The ribs on the rear wall are close to a circuit board of the circuit board assembly. The connector block has protuberances that abut against the ribs.