Control Moment Gyroscope Rotor Pre-Compression via Interference Fit
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Solution Overview
Problem
Control moment gyroscopes face limitations in rotational speed due to weld joint fatigue caused by alternating tension and compression cycles, which restricts the generation of angular momentum and torque for spacecraft maneuvering.
Innovation Solution
A control moment gyroscope assembly featuring a secondary rim made of steel, thermally coupled to the primary rim in an interference fit, compressing the rotor and maintaining weld joints in a state of compression, thereby preventing fatigue and allowing higher rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the rotor spins at higher speeds to generate more angular momentum, then the performance and effectiveness of the control moment gyroscope is improved, but the weld joints experience increased tension stress and fatigue which limits the maximum rotational speed
Solution Approach 1:
The patent changes the stress state parameter of the weld joints from alternating tension-compression cycles to sustained compression by applying pre-compressive force. This parameter change allows the weld joints to withstand higher rotational speeds without fatigue failure, as compression stress prevents the tensile stress that causes fatigue in conventional designs.
Solution Approach 2:
The patent applies preliminary compressive force to the weld joints through the pre-compression mechanism (springs or adjustable arms) before the rotor begins spinning. This preliminary anti-action counteracts the tensile stress that would normally develop during rotation, preventing fatigue accumulation and enabling higher rotational speeds.
2Strength
If the rotor mass is increased to generate more angular momentum, then the torque and effectiveness for spacecraft maneuvering is improved, but the tension stress on the weld joints increases which reduces the maximum operational speed
Solution Approach 1:
The patent changes the stress state parameter of the weld joints from alternating tension-compression cycles to sustained compression by applying pre-compressive force. This parameter change allows the weld joints to withstand higher rotational speeds without fatigue failure, as compression stress prevents the tensile stress that causes fatigue in conventional designs.
Solution Approach 2:
The patent applies preliminary compressive force to the weld joints through the pre-compression mechanism (springs or adjustable arms) before the rotor begins spinning. This preliminary anti-action counteracts the tensile stress that would normally develop during rotation, preventing fatigue accumulation and enabling higher rotational speeds.
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 enables the rotor to spin at higher speeds, generating greater angular momentum and torque while reducing weld joint fatigue, enhancing the stability and performance of the gyroscope for spacecraft control.
Implementation Method 1
heating the secondary rim until the secondary rim expands to a state where the inner diameter exceeds the outer diameter
Implementation Method 2
cooling the secondary rim, causing the secondary rim to contract around the primary rim and thereby create an interference fit
Implementation Method 3
The interference fit causes the secondary rim to compress the rotor in the direction of the shaft such that the first weld joint and the second weld joint are in compression as the rotor spins
Data Source
AI summary
A control moment gyroscope assembly including, but not limited to, a rotor that includes a shaft, a primary rim and a web that connects the shaft to the primary rim. The rotor is made from a metal material and is adapted to spin about the shaft. The control moment gyroscope assembly further includes a secondary rim that is made of the metal material and that is disposed around the rotor. The secondary rim is configured to compress the rotor in the direction of the shaft.