High-Voltage Connector Structure for Creepage Isolation
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Solution Overview
Problem
High voltage connectors with press-fit contacts face challenges in maintaining electrical isolation due to potential leakage currents and moisture ingress, especially during the overmolding process, which can cause shorts and impaired isolation.
Innovation Solution
The connector features a plastic body with metallic strips that have through holes to secure the strips in place during overmolding and are surrounded by ring-shaped beads to increase creepage distance, along with protrusions for correct positioning, enhancing electrical isolation and preventing moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metallic strips are held inside the mold by pins during overmolding, then the position of metallic strips is fixed and they are not moved by injected plastic, but the pins create through holes in the metallic strips which may impair electrical isolation
Solution Approach 1:
Ring-shaped beads are introduced as intermediary structures surrounding the through holes in the metallic strips. These beads increase the creepage distance and prevent leakage currents from flowing directly through the holes, thereby maintaining electrical isolation while allowing the pins to hold the metallic strips in place during overmolding
Solution Approach 2:
The solution adds a dimensional element by surrounding the through holes with ring-shaped beads that extend radially outward. This creates an additional protective dimension around the holes, increasing the creepage path length and preventing direct electrical contact through the holes without adding significant length to the metallic strips themselves
2Ease of manufacture
If openings are present in the plastic body for pin insertion, then metallic strips can be secured during overmolding, but leakage current may flow along the surface of the plastic body and adjacent opening to neighboring strips, impairing electrical isolation
Solution Approach 1:
Ring-shaped beads act as intermediary structures that surround the openings in the plastic body where pins are inserted. These beads create an insulating barrier that increases the creepage distance along the surface of the plastic body, preventing leakage currents from flowing to neighboring metallic strips while still allowing pin insertion for the overmolding process
Solution Approach 2:
The opening in the plastic body is effectively segmented by the ring-shaped bead that surrounds it. This segmentation creates distinct electrical zones, isolating the area around each opening from neighboring openings and metallic strips, thereby preventing continuous leakage current paths while maintaining the structural integrity needed for manufacturing
3Reliability
If moisture is present in air surrounding the connector, then leakage current may flow more easily along the surface, but adding protection against moisture increases device complexity
Solution Approach 1:
The ring-shaped beads serve as intermediary structures that provide both electrical isolation and moisture protection. By increasing the creepage distance and creating a physical barrier around the openings, they prevent moisture from facilitating leakage currents without requiring additional separate protective components, thus maintaining electrical isolation in humid conditions while minimizing device complexity
Data Source
AI summary
Disclosed is a connector for a high voltage connection inside an electrical device, especially for electrically connecting a heating plate to a printed circuit board inside a heating device. The connector has a plastic body and several metallic strips that each have two ends that protrude from the plastic body. The metallic strips form press-fit contacts at least at one of their ends, each metallic strip has a through hole that matches with a corresponding opening of the plastic body, and the plastic body has ring-shaped beads that each surround one of the openings. Also disclosed is a heating device having a heating plate, a printed circuit board, and such a connector electrically connecting the heating plate to the printed circuit board.