Electrical Junction Box Narrow Pitch Terminal Assembly
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Solution Overview
Problem
Existing electrical junction boxes with fuse attachment portions arranged side by side face challenges in achieving a narrow pitch while ensuring ease of assembly and stable connection of connecting terminals, often requiring significant time and effort due to the need for precise insertion of support pins.
Innovation Solution
The design incorporates L-shaped connecting terminals with recesses at the bend and temporal retaining portions in the terminal support block, allowing for temporary positioning of the terminals during assembly, which reduces the need for protrusions and facilitates easier insertion of support pins, enabling a narrower pitch and improved rigidity, thus simplifying the assembly process and enhancing stability during fuse removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If support pins are inserted into the terminal support block to engage connecting terminals, then the connecting terminals are supported stably against pushing forces during fuse insertion, but a large number of connecting terminals require significant time and effort for assembly
Solution Approach 1:
The connecting terminals are pre-positioned in the terminal support block before fuse insertion. This preliminary positioning ensures that when fuses are inserted and push the connecting terminals, the terminals are already in the correct location and orientation, eliminating the need for time-consuming adjustment during assembly while maintaining stable connection
2Area of stationary object
If connecting terminals are arranged with narrow pitch to increase space efficiency, then more fuse attachment portions can be accommodated, but the connecting terminals may deform during assembly and require protrusions that increase complexity
Solution Approach 1:
The connecting terminals have different cross-sectional shapes at different locations: the front end portion has a rectangular cross-section for insertion and engagement, while the rear end portion has a circular cross-section for soldering. This local variation in geometry allows the terminals to be arranged with narrow pitch without requiring additional protrusions, maintaining both space efficiency and structural simplicity
Data Source
AI summary
An electrical junction box has fuse attachment portions arranged side by side and open to a lateral side of a box body. Recesses (88) are formed at opposite side edges of an L-shaped bend (78) of each of connecting terminals (48a-48c), and in a terminal support block (42) in which a plurality of terminal insertion holes (54a) to (54c) are formed and support pins (74) that lock the connecting terminals (48a) to (48c) are inserted, temporal retaining portions (68) are formed in respective opening ends (70) of the terminal insertion holes (54a-54c) on a terminal insertion side, the temporal retaining portions (68) temporarily positioning the connecting terminals (48a) to (48c) within the respective terminal insertion holes (54a-54c) by the recesses (88) of the connecting terminals (48a) to (48c) being fit into the temporal retaining portions (68).