Rotary Pylon Actuator Using Redundant Differential Planetary Drive
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ball-screw type actuators for tiltrotor aircraft pyramids are susceptible to jamming from foreign object debris and have limited motion due to exposure of components, and can be hindered by jams between the ball-screw and nut.
Innovation Solution
A rotary differential planetary drive actuator system with redundant differential planetary elements, which includes an outer and inner differential planetary system, providing continuous operation and full range of motion even in the event of mechanical failure, with components enclosed to prevent jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ball-screw type actuator is used to actuate the proprotor pylon, then the system can achieve linear motion between airplane mode and helicopter mode, but the components are exposed and susceptible to jamming from foreign object debris
Solution Approach 1:
The differential planetary drive system employs nested gears where the planet gears rotate within the annular gear, and the entire assembly is contained within a housing. This nested configuration encloses all moving components, preventing foreign object debris from causing jams while maintaining the actuation function.
Solution Approach 2:
The actuator utilizes a enclosed housing that acts as a protective shell around the differential planetary drive components. This enclosure isolates the internal mechanism from the external environment, preventing contamination from foreign objects while allowing the actuator to function reliably.
2Ease of operation
If a ball-screw actuator is used with exposed components, then the structure is simpler, but the system has limited motion when subjected to a jam between the ball-screw and the nut
Solution Approach 1:
The actuator divides the drive function into two independent differential planetary systems instead of using a single ball-screw mechanism. This segmentation means that if one system experiences a jam, the other system can continue to provide motion, ensuring full range of motion is maintained under fault conditions.
Solution Approach 2:
The redundant differential planetary system is designed as a fail-safe mechanism that compensates for potential jams before they completely disable the actuator. The second independent system acts as a backup that automatically takes over or provides continued motion capability when the first system is jammed.
3Reliability
If redundant differential planetary elements are used, then continuous operation is provided even in the event of mechanical failure, but the device complexity increases
Solution Approach 1:
The patent combines two differential planetary drive systems into a single integrated actuator assembly that shares common mounting structures, housings, and control mechanisms. This merging approach provides redundant functionality while minimizing the increase in overall device complexity through shared components.
Solution Approach 2:
The differential planetary elements are designed to serve multiple functions: they provide the primary actuation mechanism, serve as the redundant backup system, and can operate independently or in conjunction with each other. This multi-functionality reduces the need for separate dedicated backup components, thereby limiting complexity growth.
Data Source
AI summary
A tiltrotor aircraft can include a pylon rotatable about a conversion axis. A first differential planetary assembly can include a first housing; a first ring gear; a first differential planetary gear having a first output portion; and a first differential sun gear. A second differential planetary assembly can include a second housing; a second ring gear; a second differential planetary gear having a second output portion; and a second differential sun gear. The first output portion is coupled to the second housing such that the second housing rotates at a first output speed. Further, the second output portion is coupled to the shaft, the shaft being coupled to the pylon such that rotation of the shaft rotates the pylon.