Conductive Bearing Structure With Low-Friction Sliding Layer
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Solution Overview
Problem
Conventional bearings lack improved electrical properties while maintaining a longer assembly lifetime, particularly in applications where electrical conductivity between components is necessary, such as in automotive assemblies.
Innovation Solution
The development of electrically conductive bearings featuring a substrate, typically made from metals like stainless steel, with a non-conductive or low-conductive sliding layer and protrusions that become conductive upon installation by removing the sliding layer at contact points, allowing for electrical conductivity between components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-conductive sliding layer is applied to the bearing substrate, then friction is reduced and wear is minimized, but electrical conductivity between components is lost
Solution Approach 1:
The bearing surface is segmented into two distinct zones: a non-conductive sliding layer covering most of the surface for friction reduction, and conductive protrusions emerging at specific contact points for electrical conductivity. This segmentation allows the bearing to simultaneously achieve low friction and electrical conduction by assigning different functional properties to different spatial regions of the same component.
Solution Approach 2:
The bearing exhibits local quality variation where the sliding layer provides non-conductive properties at the bulk surface for wear protection, while localized protrusions provide conductive properties at contact points. This local differentiation enables the bearing to fulfill contradictory requirements by having different material properties at different locations - non-conductive where friction reduction is needed, and conductive where electrical contact is required.
2Object-generated harmful factors
If a conductive material is used for the bearing, then electrical conductivity is achieved, but friction and wear increase
Solution Approach 1:
The bearing surface is divided into a non-conductive sliding layer that covers the majority of the surface area to minimize friction and wear, with conductive protrusions localized only at the contact points where electrical conductivity is required. This segmentation ensures that the conductive material is present only where necessary for electrical contact, while the non-conductive material dominates the friction-bearing surfaces.
Solution Approach 2:
The bearing exhibits spatially varying material properties: the bulk sliding layer possesses non-conductive, low-friction properties for wear protection, while the localized protrusions possess conductive properties for electrical contact. This local quality differentiation resolves the contradiction by having conductive properties only where needed for electricity conduction,而非 across the entire bearing surface where it would increase friction.
3Duration of action of stationary object
If the sliding layer is made thicker for better wear protection, then bearing lifetime increases, but electrical conductivity through the bearing is reduced
Solution Approach 1:
The bearing structure segments the sliding layer thickness into two regimes: a thicker non-conductive sliding layer in the bulk for wear protection and extended lifetime, and a thinner or absent sliding layer at the protrusion contact points for electrical conductivity. This segmentation allows the bearing to achieve both long service life through substantial wear protection and effective electrical contact through localized thinning at critical points.
Solution Approach 2:
The sliding layer exhibits local thickness variation: thicker regions provide enhanced wear protection and extended bearing lifetime, while thinner or absent regions at the protrusions provide low electrical resistance paths. This local quality differentiation in sliding layer thickness resolves the contradiction between lifetime extension and electrical conductivity by having different thicknesses at different locations.
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
These bearings provide enhanced electrical conductivity and reduced friction, improving assembly performance and longevity by forming a conductive path between inner and outer components, while minimizing noise and vibration.
Implementation Method 1
at least one protrusion is adapted to contact an opposing component such that at a point of contact the bearing has a void area free of sliding layer so as to provide electrical conductivity between the bearing and the opposing component
Implementation Method 2
an electrically non-conductive or low-conductive sliding layer coupled to the substrate... reduced friction
Data Source
AI summary
A bearing including a generally cylindrical sidewall including an electrically conductive substrate, and an electrically non-conductive or low-conductive sliding layer coupled to the substrate, where the generally cylindrical sidewall includes a plurality of protrusions protruding radially inward or radially outward from a bore defining a central axis, where at least one protrusion is adapted to contact an opposing component such that at a point of contact the bearing has a void area free of sliding layer so as to provide electrical conductivity between the bearing and the opposing component, and wherein at least one protrusion has a spring rate of not greater than 30 kN/mm, such as not greater than 25 kN/mm, such as not greater than 15 kN/mm, or such as not greater than 10 kN/mm.