Lead-Free Variable Resistor Coating for Smooth Sliding Contact
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increase in conductive particles in lead-free resistor materials leads to increased film surface roughness, resulting in deteriorated sliding characteristics and wear, affecting electrical and life performance.
Innovation Solution
A resistor with a more-conductor-containing layer and a more-insulator-containing layer, both lead-free, where the film surface is polished to a specific range (0.1% to 10% of the coating film amount) to reduce roughness and improve sliding characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive particles are increased in lead-free resistor material, then lead-freeness is achieved, but film surface roughness increases and sliding characteristics deteriorate
Solution Approach 1:
The resistor coating film is divided into two distinct layers: a lower layer with higher conductive particle content for electrical conductivity, and an upper layer with lower conductive particle content for smooth surface and good sliding characteristics. This segmentation allows each layer to optimize its function independently.
Solution Approach 2:
Different regions of the coating film have different compositions tailored to local requirements. The lower layer near the substrate has more conductive particles for conductivity, while the upper layer near the surface has fewer conductive particles for smoothness, creating local quality variations that resolve the contradiction.
2Reliability
If conductive particles are increased in resistor material, then electrical conductivity is improved, but wear increases and life characteristics deteriorate
Solution Approach 1:
The coating is segmented into functional layers where the lower layer provides electrical conductivity through higher conductive particle content, while the upper layer provides wear resistance and extended life through lower conductive particle content and smoother surface.
Solution Approach 2:
The resistor coating uses a composite structure with two layers having different material compositions. The lower layer is richer in conductive particles for conductivity, while the upper layer is poorer in conductive particles but provides protective properties for reduced wear and extended service life.
3Reliability
If conductive particles are increased in resistor material, then lead-freeness is achieved, but sliding characteristics deteriorate
Solution Approach 1:
The coating film is segmented into two layers with different conductive particle contents. The upper layer has reduced conductive particle content specifically to provide a smooth surface that facilitates easy sliding of the contact, while the lower layer maintains lead-free conductivity.
Solution Approach 2:
The surface region of the coating has different composition from the bulk - specifically, the upper layer has fewer conductive particles creating a locally optimized surface quality for sliding, while the overall structure remains lead-free for reliability.
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 approach achieves lead-free manufacturing while preventing the deterioration of sliding characteristics and enhancing the electrical performance by reducing wear and improving the smoothness of the film surface.
Implementation Method 1
polishing a film surface of the coating film
Data Source
AI summary
With a resistor, a variable resistor, and a method for manufacturing a resistor according to the present invention, it is possible to eliminate lead and prevent deterioration of sliding characteristics. A resistor according to the present invention is disposed on an insulating layer. The resistor has: a more-conductive-material-containing layer containing more conductive materials than insulating materials; and a more-insulating-material-containing layer that does not contain lead and that contains more insulating materials than conductive materials. The more-conductive-material-containing layer has a polished surface. For example, the film thickness of the more-conductive-material-containing layer in a low-resistance region having a resistance value smaller than or equal to a prescribed value is larger than the film thickness of the more-insulating-material-containing layer in a high-resistance region having a resistance value larger than the prescribed value.