Dielectric Spherical Bearing Electrical Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft made with composite materials face challenges in managing electrical currents from electromagnetic effects like lightning, requiring reliable electrical isolation to prevent arcing while allowing grounding for high-voltage events, which existing solutions either add weight, cost, or are unreliable, especially in cold temperatures.
Innovation Solution
The use of dielectric spherical bearings with a conditionally non-conductive coating or insert, which provides electrical isolation during normal operations and allows conductivity during high-voltage events like lightning strikes, using materials like PTFE to prevent current flow through the bearing, ensuring safe grounding without arcing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flexible electrical jumpers are used to provide electrical ground path, then electrical grounding is achieved, but cost, device complexity, and weight increase
Solution Approach 1:
The patent extracts the electrical isolation function from separate components (jumpers, sealant) and integrates it directly into the bearing structure through a non-conductive liner or coating on the bearing races. This eliminates the need for additional electrical isolation components while maintaining both mechanical bearing function and electrical isolation properties.
Solution Approach 2:
The patent combines multiple functions into the bearing component itself: mechanical support, lubrication, and electrical isolation. By incorporating the non-conductive liner or coating directly on the bearing races, the bearing simultaneously provides mechanical function and electrical isolation without requiring separate components.
2Reliability
If non-conductive lubricant is used in bearing, then electrical isolation is achieved, but EME effects with high voltage may cause arcing through air gaps
Solution Approach 1:
The patent applies local quality by providing electrical isolation specifically at the bearing race surfaces where electrical isolation is most critical. The non-conductive liner or coating is applied to the inner and/or outer race surfaces, providing localized electrical isolation at the interfaces where arcing is most likely to occur, while maintaining mechanical bearing function.
3Weight of moving object
If composite materials are used to reduce weight, then structural strength-to-weight ratio improves, but electrical conductivity for EME dissipation deteriorates
Solution Approach 1:
The patent uses composite materials approach by combining conductive and non-conductive properties within the bearing structure. The bearing consists of conductive metal components (balls, cages, race substrates) combined with non-conductive liners or coatings, creating a composite structure that provides both mechanical strength and controlled electrical isolation properties.
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
The dielectric spherical bearings effectively isolate normal electrical currents while ensuring sufficient conductivity for electromagnetic effects, preventing arcing and maintaining structural integrity and reliability, even in cold temperatures, without adding significant weight or cost.
Implementation Method 1
a conditionally non-conductive bearing liner (coating 914) is wrapped or molded around corners of the outer-race inner surface 908 and the outer-race side face 910
Implementation Method 2
using materials like PTFE to prevent current flow through the bearing
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A method of providing conditional electrical isolation for a bearing is disclosed. An inner race coupled to a first structure and an outer race coupled to a second structure are provided. An isolative means is provided for conditionally electrically isolating the first structure from the second structure.