Film Capacitor Guide Groove Structure to Prevent Terminal Damage
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Solution Overview
Problem
Existing film capacitors face the risk of lead-out terminal damage when inserted into an outer case with guide grooves, as the terminals can rub against the edges of the grooves, leading to damage and potential metal chip generation.
Innovation Solution
The capacitor design incorporates an outer case with a guide groove that has a lower height proximal to the opening part compared to the side wall, and the corner of the guide groove edge is chamfered, reducing the risk of terminal damage and metal chip scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If guide grooves are provided in the resin case to prevent the capacitor element from tilting, then the capacitor element positioning is improved, but the lead-out terminals may rub against the edges of the guide grooves causing damage
Solution Approach 1:
The guide groove is designed with non-uniform cross-sectional dimensions, being wider at the opening part and narrower at the bottom. This local variation in geometry allows the groove to fulfill multiple functions: providing positioning guidance while preventing lead-out terminal contact with sharp edges. The varying width creates a protective effect at different locations along the groove
Solution Approach 2:
Instead of making the guide groove uniform or narrower at the opening, the invention inverts the conventional approach by making it wider at the opening and narrower at the bottom. This inverted geometry allows lead-out terminals to pass through more easily at the opening while still providing positioning constraints at the narrower bottom section, thus preventing both terminal damage and element tilting
2Ease of manufacture
If the guide groove has a uniform cross-section, then the manufacturing is simpler, but the lead-out terminals are at risk of rubbing against the edges
Solution Approach 1:
The guide groove incorporates local quality variations with different cross-sectional dimensions at different locations. The opening part has a larger cross-section to prevent terminal rubbing, while the bottom has a smaller cross-section for positioning. This local differentiation resolves the contradiction between manufacturing simplicity and terminal protection
3Manufacturing precision
If the guide groove is made deeper to better regulate terminal position, then the positioning accuracy is improved, but the risk of terminal damage increases due to longer contact path
Solution Approach 1:
The guide groove uses local quality variation where the cross-sectional width changes along the depth. The upper portion has wider dimensions that prevent terminal contact and rubbing, while the lower portion narrows to provide positioning regulation. This ensures that the terminal does not contact the groove edges during insertion, even though the groove is sufficiently deep for position control
Data Source
AI summary
A capacitor that includes: a capacitor element including an element body and an external electrode on an end surface of the element body; a lead-out terminal electrically connected to the external electrode; an outer case housing the capacitor element inside so that the lead-out terminal projects outward, the outer case having: a bottomed tubular shape, a guide groove constructed to regulate a position of the lead-out terminal on an inner surface of the outer case, the guide groove protruding from a side wall and extending between an opening part and a bottom wall, wherein a height of the guide groove proximal to the opening part is lower than a height of the side wall proximal to the opening part or a corner of an edge of the guide groove proximal to the opening part is chamfered.