Flexible Coupling Mitigates Mast Deflection Loads on Rotorcraft Slip Rings
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Solution Overview
Problem
In rotorcraft applications where the slip ring is positioned within the mast and constrained by its size, mast deflections induce high loads that can cause the slip ring to rub against the standpipe assembly, leading to premature failure and reduced lifespan due to bending moments and reactive radial loads.
Innovation Solution
A flexible coupling is introduced in the standpipe assembly, featuring a spring section with a helical slot to accommodate angular, axial, and torsional displacements caused by rotor mast bending, allowing for relative movement between the slip ring rotor and stator while maintaining electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid coupling is used to connect the standpipe assembly to the slip ring, then structural strength and stability are improved, but the slip ring is subjected to high loads from mast deflections causing premature failure
Solution Approach 1:
The patent applies a flexible coupling with a bellows-like structure between the standpipe assembly and slip ring. This flexible element can expand and contract to accommodate mast deflections while maintaining the connection, thereby protecting the slip ring from high loads caused by rigid coupling.
Solution Approach 2:
The flexible coupling changes the mechanical parameters of the connection by introducing compliance. It allows relative movement and deformation to absorb mast deflections, transforming the rigid connection into a compliant one that protects the slip ring from excessive forces.
2Volume of moving object
If the slip ring is positioned within the mast to reduce size constraints, then spatial efficiency is improved, but mast deflections induce high reactive radial loads on the slip ring bearings leading to premature failure
Solution Approach 1:
The flexible coupling acts as an intermediary element between the standpipe assembly and the slip ring. It mediates the forces transmitted through the connection, absorbing and dampening the reactive radial loads that would otherwise be directly imposed on the slip ring bearings during mast deflections.
3Reliability
If a rigid connection is maintained between the slip ring rotor and stator, then electrical connectivity is ensured, but bending movement causes rubbing and chips that fall into the gearbox damaging components
Solution Approach 1:
The flexible coupling provides a compliant connection that can accommodate relative movement between the rotor and stator without causing rubbing. The flexible bellows structure allows the necessary displacement while maintaining the electrical connection, preventing chip generation that would contaminate the gearbox.
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 flexible coupling mitigates the effects of mast deflections, reducing the risk of slip ring failure and gearbox damage by absorbing reactive loads and maintaining efficient power transfer.
Implementation Method 1
A flexible coupling is introduced in the standpipe assembly, featuring a spring section with a helical slot to accommodate angular, axial, and torsional displacements caused by rotor mast bending
Data Source
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AI summary
A standpipe assembly for a rotorcraft (100) includes a slip ring (204) positioned within the mast (114) of the rotorcraft (100). The slip ring (204) includes a stator (304) rotationally connected to a rotor (302). A flexible coupling (202) is connected to the stator (304) and a standpipe tube (206) is connected to the flexible coupling (202). The flexible coupling (202) is capable of angular, axial, and torsional displacement.