Electrical Connection Box Bolt Groove for Terminal Alignment
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Solution Overview
Problem
Conventional electrical connection systems experience increased contact resistance due to curved surfaces at the intersection of bolt and terminal interfaces, leading to misalignment and reduced contact area, which affects the reliability of large current conduction in automotive power supply systems.
Innovation Solution
The formation of a groove over the entire circumference of the bolt at the intersection of the seat surface and outer circumferential surface prevents a curved surface from forming, allowing for reduced through-hole diameters without terminal misalignment, ensuring proper contact and alignment of bus bar and electrical wire terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the through-hole diameter is reduced to ensure sufficient contact area between terminals, then contact area increases, but the hole edge becomes caught on the curved surface at the bolt-seat intersection, causing misalignment and increased contact resistance
Solution Approach 1:
The invention extracts and removes the harmful curved surface at the intersection of the seat surface and outer circumferential surface of the bolt shaft by providing a groove portion. This eliminates the obstacle that causes terminal misalignment while maintaining the reduced through-hole diameter design, thereby resolving the contradiction between contact area and alignment precision.
Solution Approach 2:
The groove portion is formed in advance on the bolt before terminal assembly, preemptively eliminating the curved surface that would cause misalignment. This preliminary action ensures that when terminals with reduced through-hole diameters are assembled, their hole edges will not be caught on any curved surface, guaranteeing proper alignment and low contact resistance.
2Ease of manufacture
If a curved surface is formed at the boundary portion between seat surface and outer circumferential surface of the bolt shaft, then the bolt can be molded using a die, but the terminal hole edge becomes caught on the curved surface, increasing contact resistance
Solution Approach 1:
The harmful curved surface that complicates terminal alignment is extracted and removed by introducing a groove portion at the critical intersection area. This allows the bolt to maintain its die-molded manufacturing process while eliminating the alignment-obstructing curved surface, thus resolving the contradiction between ease of manufacture and reliability.
Solution Approach 2:
The groove portion is localized specifically at the intersection of the seat surface and outer circumferential surface where the problem occurs, while the rest of the bolt maintains its standard molded structure. This local modification eliminates the harmful curved surface effect without complicating the overall manufacturing process, balancing ease of manufacture with reduced contact resistance.
Data Source
AI summary
An electrical connection box includes: a circuit portion having bus bars including bus bar terminal portions; a case housing a circuit portion with electronic components mounted thereon; a through-hole is formed in each of the bus bar terminal portions; electrical wire terminal portions are connected to electrical wires, a through-hole is formed in each electrical wire terminal portions; stud bolts having a shaft portion and a head portion; and nuts are fastened to the stud bolts. The shaft portion is inserted into the through-holes of both the bus bar terminal portions and the electrical wire terminal portions, the bus bar terminal portions and the electrical wire terminal portions are overlaid on seat surfaces of the stud bolts, and a groove portion is formed over the entire circumference of each of the stud bolts where the seat surface and the outer circumferential surface of the shaft portion intersect.