Capacitor Base Structure to Suppress Resin Capillary Movement
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Solution Overview
Problem
The resin layer in capacitors experiences a force directed outward due to capillary action, causing it to move and adhere to the terminal leads, which can obstruct soldering and reduce the amount of resin filling the capacitor.
Innovation Solution
The capacitor design includes a base with a protruding portion surrounding the insertion through hole, and an opening sealing member with a protruding portion that contacts the base, creating a larger opening distance on the substrate mounting face to suppress capillary action and resin movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin layer is formed between the opening sealing body and the base by injecting liquid-like resin, then the sealing property of the capacitor is enhanced, but the resin moves toward the outer side of the base due to capillary action and adheres to the periphery of the terminal leads, obstructing soldering
Solution Approach 1:
A protruding portion is formed on the base surrounding the insertion through hole before resin injection. This preliminary structural preparation creates a physical barrier that prevents resin from moving to the outer side of the base, thereby preventing adhesion to terminal leads while still allowing resin to fill the capacitor effectively
Solution Approach 2:
The protruding portion acts as an intermediary structure between the insertion through hole and the outer side of the base. It mediates the resin flow by providing a barrier that stops capillary action from pulling resin outward, thus protecting the terminal leads from resin adhesion
2Reliability
If the opening distance on the substrate mounting face is increased to suppress capillary action, then resin movement is prevented, but the structural complexity of the base increases due to the protruding portion
Solution Approach 1:
The base structure is segmented by adding a protruding portion that divides the insertion through hole into distinct regions. This segmentation creates a larger opening distance on the substrate mounting face, effectively suppressing capillary action and preventing resin movement while maintaining manufacturing feasibility
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
This design effectively suppresses the force and movement of the resin caused by capillary action, preventing obstruction of soldering and ensuring consistent resin filling, thereby improving the reliability and uniformity of the capacitor.
Implementation Method 1
the viscosity thereof is lowered immediately before the hardening. The thermo-setting resin that is disposed between the terminal leads and the base, and that has the low viscosity consequently receives a force in the direction toward the outer side of the base caused by the capillary action.
Data Source
AI summary
A capacitor (2) includes a capacitor main body (4) and a base (6). The capacitor main body includes an opening sealing member (14) attached to an opening of an outer package case (10), and a terminal lead (16-1, 16-2) led out from a first insertion through hole portion (17-1, 17-2) of the opening sealing member. The base is disposed on the side of the opening sealing member of the capacitor main body, and has a second insertion through hole portion (18-1, 18-2). For example, the base includes a first protruding portion (20) surrounding the second insertion through hole portion, so that the second insertion through hole portion of the base forms an insertion through hole. The opening distance on the side of the substrate mounting face of the insertion through hole is larger than the opening distance on the side of the capacitor main body of the insertion through hole.