Multimode Clutch Assembly for Rotorcraft Supplemental Rotor Power
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Solution Overview
Problem
Conventional rotorcraft systems lack the capability for an auxiliary power unit to provide supplemental power to the main rotor during high power demand flight operations, limiting their versatility and efficiency.
Innovation Solution
A multimode clutch assembly that enables the secondary engine to operate as a supplemental power unit, providing power to the main rotor independently or in conjunction with the main engine, through a unidirectional and bidirectional torque transfer mode, allowing for efficient power distribution during varying flight operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dedicated auxiliary power unit is used for preflight accessory power, then accessory power during preflight operations is provided, but the unit cannot provide supplemental power to the main rotor during high power demand flight operations
Solution Approach 1:
The auxiliary power unit is designed to perform multiple functions: it can operate as a dedicated accessory power source during preflight operations and as a supplemental power unit for the main rotor during high power demand flight operations. This multi-functionality eliminates the need for separate dedicated units for different operational phases.
Solution Approach 2:
The clutch assembly dynamically switches between unidirectional and bidirectional torque transfer modes based on operational requirements. The system can transition from accessory-only power mode to combined main rotor and accessory power mode, adapting to different flight phases and power demand conditions.
2Power
If multiple main engines or supplemental power units are used for high power demand operations, then required power for the main rotor is generated, but system complexity and weight increase
Solution Approach 1:
The auxiliary power unit serves dual purposes: providing accessory power during normal operations and acting as a supplemental power source for the main rotor during high power demand conditions. This eliminates the need for completely separate supplemental power systems.
Solution Approach 2:
The clutch assembly merges the auxiliary power unit's output with the main rotor drive system, allowing torque from the auxiliary unit to be combined with main engine power. This integration enables a single auxiliary unit to fulfill multiple power needs rather than requiring separate systems.
3Adaptability or versatility
If the auxiliary power unit is integrated to provide both accessory and main rotor power, then power efficiency and versatility improve, but clutch assembly complexity increases
Solution Approach 1:
The clutch assembly is divided into distinct functional components: a unidirectional clutch for accessory power transfer and a bidirectional clutch for main rotor power transfer. This segmentation allows each clutch to be optimized for its specific function while working together in an integrated system.
Solution Approach 2:
The clutch assembly acts as an intermediary mechanism between the auxiliary power unit and two different load paths: one leading to accessories and another to the main rotor. This intermediary structure enables selective engagement and disengagement of power paths based on operational requirements.
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
Enhances the rotorcraft's power efficiency and safety by enabling the secondary engine to provide emergency power and reduce main engine load, allowing for downsizing and improved single-engine operations, while maintaining fail-safe operations and autorotation capabilities.
Implementation Method 1
The clutch includes a one-way bearing allowing rotation in a first direction
Implementation Method 2
a number of actuatable pawls in one race and a number of receiving slots having engagement faces in another race
Implementation Method 3
the pawls are retained inward by actuator rods
Data Source
Figure 1A~1B
Figure 1C
Figure 2A~2B
AI summary
A multimode clutch assembly (128) is positioned in a powertrain of a rotorcraft. The multimode clutch assembly includes a freewheeling unit (130) having input and output races (136, 140). The freewheeling unit has a driving mode in which torque applied to the input race is transferred to the output race and an overrunning mode in which torque applied to the output race is not transferred to the input race. A bypass assembly (132) has an engaged position that couples the input and output races of the freewheeling unit. A hydraulic actuator (134) shifts the bypass assembly between the engaged position and a disengaged position. In the disengaged position, the overrunning mode of the freewheeling unit is enabled such that the multimode clutch assembly is configured for unidirectional torque transfer. In the engaged position, the overrunning mode of the freewheeling unit is disabled such that the multimode clutch assembly is configured for bidirectional torque transfer.