Movable Contact Wire Structure for Lower-Cost Variable Resistors
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Solution Overview
Problem
Variable resistors with lead-free inks and beryllium copper contacts face challenges in achieving adequate properties, and existing solutions using precious metal contacts result in increased costs due to complex assembly processes.
Innovation Solution
A movable contact system comprising a first wire rod group of precious metals and a second wire rod group of non-precious metals, both arranged orthogonally and welded together with a shaft-shaped member, allowing for a simpler and cost-effective assembly by adjusting the melting times during resistance welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact part made of precious metal alloy is welded and fixed to the support part via an attachment member, then adequate contact properties are obtained, but the number of components and assembly man-hours increase leading to cost increase
Solution Approach 1:
The patent combines the precious metal contact part and the support part into a single integrated component. The precious metal layer is directly formed on the support part through plating, eliminating the need for separate attachment members and welding processes. This merging of components maintains adequate contact properties while reducing assembly complexity and cost.
2Reliability
If a contact part made of precious metal alloy is welded and fixed to the support part via an attachment member, then adequate contact properties are obtained, but assembly man-hours increase leading to cost increase
Solution Approach 1:
The support part and contact part are merged into a single integrated component where the precious metal layer is directly plated onto the support part. This eliminates the separate welding and assembly steps, significantly reducing assembly man-hours while maintaining adequate contact properties through the direct metal-to-metal contact.
3Object-affected harmful factors
If a resistor printed with lead-free ink and a contact part made of beryllium copper are used, then global environmental conservation is achieved, but adequate properties cannot be obtained
Solution Approach 1:
The patent uses a composite structure where a lead-free resin ink layer is combined with a precious metal plating layer. The lead-free resin ink provides environmental compliance, while the precious metal plating (such as nickel, copper, or silver) on the contact surfaces provides adequate electrical contact properties. This composite approach resolves the contradiction between environmental conservation and performance requirements.
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 configuration reduces the number of components and assembly time, effectively suppressing cost increases while maintaining adequate performance by ensuring proper contact and resistance properties.
Implementation Method 1
welding the shaft-shaped member to the first wire rod group and the second wire rod group by resistance welding
Data Source
AI summary
Provided are a movable contact, a variable resistor, and a method for manufacturing a movable contact that can suppress a cost increase. The movable contacts are spaced apart from each other. The variable resistor, having a resistor, an electrode and the movable contact, comprises: a first wire rod group which has a plurality of first wire rods made of a precious metal and in which the plurality of first wire rods are arranged along the resistor; a second wire rod group which has a plurality of second wire rods made of a metal other than the precious metal and in which the plurality of second wire rods are arranged along the electrode; and a shaft-shaped member which is disposed to cross the first wire rod group and the second wire rod group and is welded to the first wire rod group and the second wire rod group.