Distributed Wire Race Bearing for Electric Machine Weight Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rotating electrical machines face challenges in achieving a balance between minimizing weight and maintaining structural strength and rigidity, particularly in applications where size and weight constraints are significant, such as wind turbines and aircraft, while also requiring robustness to maintain the air gap and withstand operational forces.
Innovation Solution
The design incorporates a stator and rotor assembly with structural elements like stator outer flanges, stator stringers, and rotor stringers made of metal, along with bearing assemblies and compensation fastener assemblies to ensure rigidity and stiffness, while using lightweight materials and configurations like wire bearing assemblies to reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heavy components are used to build a robust electric machine that will not flex or come out of alignment during operation, then the air gap can be maintained and reliability improved, but the weight of the electric machine increases
Solution Approach 1:
The bearing assembly is divided into a outer race bearing member, inner race bearing member, and multiple ball bearings. This segmentation allows each component to be optimized independently for strength and weight, enabling the use of lightweight materials while maintaining the structural integrity needed to maintain the air gap during operation.
Solution Approach 2:
The patent employs composite material construction in the bearing assembly, combining different materials with complementary properties. The outer race, inner race, and ball bearings can be made from materials optimized for their specific functions, achieving a balance between weight reduction and maintaining the robustness required to prevent flexing and alignment issues during operation.
2Use of energy by moving object
If the distance between magnets and coils is minimized to achieve highest efficiency conversion, then energy conversion efficiency is improved, but the structural rigidity requirements increase to maintain this small air gap under operational forces
Solution Approach 1:
By segmenting the bearing assembly into separate outer race, inner race, and ball bearing components, the design allows for precise control of the air gap distance. Each component can be precisely manufactured and fitted to maintain a consistent, minimal air gap while distributing the structural loads, thereby achieving high energy conversion efficiency without compromising the structural rigidity needed to maintain that gap under operational forces.
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 allows for the creation of electric machines that are both lightweight and robust, capable of maintaining the air gap and operating efficiently under various forces, thus addressing the weight and strength constraints in demanding environments.
Implementation Method 1
The bearing assemblies may be spaced across a midpoint along a longitudinal axis of the electric machine. The bearing assemblies may position the rotor assembly for rotation with respect to the stator assembly.
Implementation Method 2
Compensation fastener assemblies may couple the wire race assembly to the rotor or stator assembly, to compensate for differential expansion (for instance, thermal differential expansion along a longitudinal axis of the electric machine).
Implementation Method 3
In the case of electric motors, passage of electrical current through various windings produces electromagnetic forces, which attract, and optionally, repel the magnets, inducing rotation.
Implementation Method 4
In the case of generators, relative movement of the magnets, typically permanent magnets, with respect to the wire windings induces an electrical current in the windings.
Data Source
AI summary
An electric machine may employ a distributed bearing, for example spaced radially outwardly of a longitudinal center of a rotor and stator assembly. The distributed bearing may take the form of a wire race bearing, which positions a rotor assembly relative to a stator assembly to maintain an air gap therebetween. The rotor assembly may be concentrically located within the stator assembly. Electrically insulative fasteners may couple a race assembly to the stator or rotor assembly. Compensation fastener assemblies may couple the wire race assembly to the rotor or stator assembly, to compensate for differential expansion for instance thermal differential expansion along a longitudinal axis of the electric machine. The electric machines may be arranged in series, for example with drive shafts arranged along a common axis, and may be coupled to the same source of motion (e.g., propeller of wind turbine, without or with a gear box).