Planar Terminal Solder Pool Design for Relay Sealing
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Solution Overview
Problem
Molten solder can infiltrate the gap between the outer side surface of the insulating substrate and the inner circumferential surface of the cover in surface mount type leadless electromagnetic relays, compromising the sealing function by coming into contact with the sealant.
Innovation Solution
An electronic device design featuring a planar terminal extending from the outer side surface to the bottom surface edge of the insulating base, forming a solder pool surrounded by the mounted portion, which collects molten solder and prevents it from entering the gap between the insulating base and the cover, with a tapered ceiling surface to inhibit solder rise and protect the sealing function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the terminal is formed integrally with the insulating substrate, then manufacturing is simplified, but the terminal surface provides a path for molten solder to reach the sealant
Solution Approach 1:
The patent applies local quality by creating a recess specifically at the bottom surface edge area where the terminal meets the substrate. This localized structural modification changes the surface topology only where needed - the terminal remains integrally formed for manufacturing simplicity, but the recessed area specifically prevents solder infiltration by collecting molten solder away from the sealant.
2Manufacturing precision
If a flat bottom surface is used, then manufacturing precision is easier to maintain, but molten solder can easily infiltrate along the terminal edge
Solution Approach 1:
The patent introduces a recess (curved or concave surface) at the bottom surface edge instead of maintaining a completely flat surface. This curved/recessed geometry prevents capillary infiltration by eliminating the sharp edges and flat surfaces that promote wick-like solder flow. The recessed shape redirects molten solder into a collection pool away from the gap between the insulating substrate and cover.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively prevents molten solder from contacting the sealant, maintaining the sealing function and ensuring reliable electrical continuity while visually confirming the solder connection to prevent poor connections.
Implementation Method 1
molten solder may get into the gap between the outer side surface of the insulating substrate 3005 and the inner circumferential surface of the cover 51 due to a capillary phenomenon
Data Source
AI summary
An electronic device where molten solder does not come into contact with a sealant so as not to destroy a sealing function. An electronic device is provided with: an insulating base mounted on a printed circuit board; a common planar terminal provided so as to extend from an outer side surface to a bottom surface edge of the insulating base, and cause electrical continuity between the outer side surface and the bottom surface edge of the insulating base; a cover fitted to the insulating base and covering the common planar terminal; and a sealant sealing a gap between the outer side surface of the insulating base and an inner circumferential surface of the cover. A solder pool is formed in a position surrounded by the printed circuit board and the common planar terminal at the bottom surface edge of the insulating base.