Monolithic CMG Rotor with Torsionally-Stiff Spokes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Control moment gyroscopes (CMGs) face challenges in achieving superior momentum-per-weight ratios, speed capabilities, and operational lifespan due to high manufacturing costs and time-consuming processes associated with shell rotor-based architectures, which include substantial weld joints that fatigue and limit performance.
Innovation Solution
The development of a monolithic CMG rotor with radially-extending torsionally-stiff spokes, fabricated as a single piece to eliminate weld joints, allowing for higher rotational speeds and torque loads, and utilizing a dual spin motor configuration for enhanced performance, along with cost-effective and time-efficient manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If shell rotor architecture with weld joints is used, then structural integrity is achieved, but manufacturing cost and time increase substantially
Solution Approach 1:
The patent merges multiple rotor components (rotor rim, rotor disks, and spokes) into a single monolithic structure fabricated from one piece of material. This eliminates the need for separate welding operations between components, directly resolving the contradiction by achieving structural integrity through monolithic construction while dramatically reducing manufacturing time and cost.
Solution Approach 2:
The monolithic rotor is designed with segmented features (spokes and disks) that are integrated into a single piece rather than separate components. This segmentation within monolithic construction allows for optimized structural performance without requiring weld joints, thereby maintaining strength while improving productivity.
2Strength
If shell rotor architecture with weld joints is used, then structural integrity is achieved, but manufacturing cost increases substantially
Solution Approach 1:
The patent combines multiple rotor components into a single monolithic structure, eliminating the need for expensive welding operations and assembly processes. This directly addresses the contradiction by maintaining structural integrity through integrated design while significantly reducing manufacturing cost.
3Productivity
If monolithic rotor design is used, then manufacturing cost and time are reduced, but torsional stiffness may be compromised
Solution Approach 1:
The patent applies local quality by designing spokes with specific geometric features (tapered profiles, optimized thickness variations) that concentrate material where torsional loads are highest. This allows the monolithic rotor to achieve adequate torsional stiffness through localized material distribution rather than uniform thickening, maintaining manufacturing efficiency while addressing stiffness requirements.
Solution Approach 2:
The rotor design incorporates dynamic considerations by optimizing spoke geometry to handle varying torsional loads during operation. The tapered and varied-thickness spoke design allows the structure to adapt stiffness characteristics to operational demands, ensuring sufficient torsional rigidity in the monolithic construction.
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 monolithic CMG rotor achieves improved momentum-to-weight ratios, increased operational longevity, and reduced mechanical fatigue, while enabling faster and more cost-effective production compared to traditional shell rotor assemblies.
Implementation Method 1
a monolithic CMG rotor including a rotor shaft, a rotor rim, and a plurality of radially-extending torsionally-stiff spokes
Implementation Method 2
a spin motor coupled to the IGA support structure and configured to rotate the monolithic CMG rotor about a spin axis
Implementation Method 3
a torque motor coupled to the stator housing and configured to rotate the IGA about a gimbal axis to selectively generate a desired output torque
Implementation Method 4
When the IGA is 'gimbaled' in this manner, a controlled torque is generated about an output axis normal to the spin and gimbal axes due to momentum transfer of the rotor assembly
Data Source
AI summary
Embodiments of control moment gyroscopes (CMGs) are provided, as are embodiments of a method for fabricating CMGs. In one embodiment, a CMG includes a stator housing, an inner gimbal assembly (IGA), and a torque motor coupled to the stator housing and configured to rotate the IGA about a gimbal axis to selectively generate a desired output torque during operation of the CMG. The IGA includes, in turn, an IGA support structure rotatably coupled to the stator housing, a monolithic CMG rotor rotatably mounted to the IGA support structure, and a spin motor coupled to the IGA support structure and configured to rotate the monolithic CMG rotor about a spin axis.