Insert-Molded Switch Contact Structure for Secure Housing Fixation
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Solution Overview
Problem
Existing switch devices face issues with the fixed contact not being firmly fixed to the housing due to a small contact area during insert molding.
Innovation Solution
The switch design incorporates extended supports on the central fixed-contact member that project in the transverse direction, serving as receivers for resin during insert molding, which enhances the contact area and fixation, while suppressing deformation and pin traces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the fixed contact member is directly molded without extended supports, then the manufacturing process is simple, but the contact area between the fixed contact and housing is insufficient leading to poor fixation
Solution Approach 1:
The fixed contact member is extended in the transverse direction (width direction) to form extended supports, transforming a point-contact or small-area contact into a larger surface contact area. This dimensional extension increases the contact area between the fixed contact and housing without adding separate components, thereby improving fixation reliability while maintaining structural integration.
Solution Approach 2:
The fixed contact member is divided into functional segments: the central fixed contact portion for electrical contact and the extended support portions for structural fixation. This segmentation allows each part to serve its specific function optimally - the fixed contact for conductivity and the extended supports for mechanical anchoring - resolving the contradiction between simple structure and reliable fixation.
2Ease of manufacture
If resin is ejected directly at the fixed contact during insert molding, then the molding process is straightforward, but the fixed contact deforms and pin traces are formed
Solution Approach 1:
The extended supports act as intermediary structures between the resin ejection process and the fixed contact. During insert molding, the resin is ejected toward the extended supports first, which absorb and distribute the molding pressure. This protects the fixed contact from direct resin impact, preventing deformation and pin traces while maintaining a straightforward molding process.
Solution Approach 2:
The extended supports are formed in advance as integral parts of the fixed contact member before the insert molding process. This preliminary structural preparation ensures that when resin is ejected during molding, the extended supports are already in position to receive and distribute the resin pressure, preventing direct impact on the fixed contact and eliminating the need for complex molding control measures.
Data Source
AI summary
A switch includes: a housing; a first fixed-contact member having a longitudinal shape; a second fixed-contact member; and a movable contact member. The housing includes a casing. The first fixed-contact member includes: a first external-connection terminal exposed from one end in a longitudinal direction of the housing; and a central fixed contact exposed from a central portion of a bottom of the casing. The first fixed-contact member extends from the first external-connection terminal to the central fixed contact in the longitudinal direction. The second fixed-contact member includes: a second external-connection terminal exposed from the other end in the longitudinal direction of the housing; and a plurality of peripheral fixed contacts exposed from a peripheral portion of the bottom of the casing. The second fixed-contact member extends from the second external-connection terminal to the plurality of peripheral fixed contacts in the longitudinal direction.