Non-Conductive Hydrodynamic Bearing for Electric Transmission Reliability
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Solution Overview
Problem
Conventional bearings in electric motor assemblies are prone to premature failure due to electrical static and current passage, requiring labor-intensive or expensive insulation coatings or shunts to prevent damage.
Innovation Solution
The use of hydrodynamic bearings made from non-conductive materials, such as polymeric or plastic materials, which are rotationally locked to the housing components, eliminating the risk of electrical damage and eliminating the need for insulation coatings or shunts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bearings are used in electric motor assemblies, then the bearings can support radial and axial loads, but the bearings are subject to electrical current passage causing premature failure
Solution Approach 1:
The patent introduces an intermediary component - the electrically insulating bearing - that mediates between the rotor and stator while blocking electrical current. This bearing is pressed against the rotor and electrically isolated from it, creating a non-conductive path that prevents current from reaching the stator winding, thus solving the electrical current damage problem while maintaining load support functionality
Solution Approach 2:
The patent changes the electrical conductivity parameter of the bearing material by selecting materials with high electrical resistance (such as certain polymers, ceramics, or composite materials). This parameter change transforms the bearing from an electrically conductive component to an electrically insulating one, preventing current passage while maintaining mechanical load-bearing capabilities
2Reliability
If insulation coatings or shunts are applied to prevent current passage, then electrical damage is prevented, but the installation becomes labor intensive and expensive
Solution Approach 1:
The patent extracts the electrical insulation function from separate components (insulation coatings or shunts) and integrates it directly into the bearing structure itself. The bearing is designed and manufactured as a single piece with inherent electrical insulation properties, eliminating the need for additional insulation components and their associated installation steps, thus reducing labor and complexity while maintaining protection from electrical damage
3Reliability
If hydrodynamic bearings made from non-conductive materials are used, then electrical current passage is prevented and bearing reliability is improved, but the device complexity increases
Solution Approach 1:
The patent designs the bearing to perform multiple functions simultaneously: it provides mechanical load support (radial and axial), enables relative rotation between rotor and stator, and blocks electrical current through its non-conductive material. By integrating these multiple functions into a single component, the patent avoids increasing device complexity while achieving improved reliability against electrical damage
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 solution effectively prevents premature failure of bearings by avoiding electrical current passage and reduces noise, vibration, and harshness (NVH) levels, while simplifying the manufacturing process by eliminating the need for high-speed cage and rolling elements.
Implementation Method 1
hydrodynamic bearing arranged between the rotor shaft and the outer housing
Data Source
AI summary
In one aspect, an improved electric transmission assembly is provided that includes a hydrodynamic bearing. The electric transmission assembly includes a stator arranged inside of an outer housing. A rotor is configured to be rotatably driven by the stator. The rotor can include a rotor shaft having a first gear configured to driveably engage with a differential. A hydrodynamic bearing is arranged between the rotor shaft and the outer housing. The hydrodynamic bearing is formed from a non-conductive material. Specifically, the hydrodynamic bearing can be formed from a polymeric or plastic material. In one aspect, the hydrodynamic bearing is formed from a non-metallic material.