Aircraft Gearbox Power Coupler for Selective Accessory Drive
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Solution Overview
Problem
Existing aircraft powerplant accessory systems lack flexibility and efficiency in power transfer configurations, leading to suboptimal performance and maintenance challenges.
Innovation Solution
Aircraft powerplant assembly with a gearbox and power coupler that allows independent operation of engine power transfer apparatuses and accessory power transfer apparatuses, enabling selective coupling and decoupling of engine and accessory power transfer systems, and includes a self-contained power coupler module for flexible power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed power transfer configuration is used in the accessory gearbox, then the structure is simple and reliable, but the system lacks flexibility and cannot optimize power transfer based on different operating conditions
Solution Approach 1:
The patent applies the dynamics principle by making the power transfer configuration changeable through a power coupler that can selectively engage different engine power transfer apparatuses (first and second engine power transfer apparatuses) with the accessory power transfer apparatus. This allows the system to adapt between direct drive and geared drive modes based on operating conditions, resolving the contradiction between flexibility and complexity by introducing a controlled variable element (the power coupler) rather than redesigning the entire gearbox structure.
Solution Approach 2:
The accessory gearbox is designed with multi-functionality by incorporating a power coupler that enables the same accessory power transfer apparatus to receive power from different engine power transfer apparatuses depending on operating mode. This universal design allows the gearbox to serve multiple functions (direct drive mode and geared drive mode) without requiring separate dedicated systems, thereby improving adaptability while managing complexity.
2Productivity
If engine accessories are always directly driven by the engine, then the power transfer is efficient at high engine speeds, but the system cannot optimize for lower engine speeds or different operational modes
Solution Approach 1:
The system dynamically switches between direct drive and geared drive modes using the power coupler engagement mechanism. At high engine speeds, the power coupler disengages to allow direct drive for maximum efficiency. At lower speeds or different operational requirements, the power coupler engages to route power through the accessory gearbox's gear system, optimizing torque and speed multiplication. This dynamic switching resolves the contradiction by adapting the power transfer path to current operating conditions.
Solution Approach 2:
The patent changes the operational parameters of the power transfer system by introducing a power coupler that can alter the gear ratio and power transmission path based on engine speed and operational mode. This parameter change capability allows the system to optimize power transfer efficiency across different operating conditions rather than being fixed at a single efficiency point, thereby resolving the contradiction between maintaining high efficiency and achieving operational flexibility.
3Volume of moving object
If the power coupler is integrated within the gearbox housing, then the structure is compact, but maintenance and replacement become more complex
Solution Approach 1:
The power coupler is designed as a separate, modular component that can be independently removed from the gearbox housing through a removable coupling mechanism. This segmentation allows the power coupler to be maintained or replaced without disassembling the entire gearbox, resolving the contradiction by separating the maintenance-intensive component (power coupler) from the structural housing, thereby improving ease of repair while maintaining a compact integrated appearance during operation.
Solution Approach 2:
The power coupler is extracted as a distinct removable element from the gearbox assembly, allowing it to be taken out for maintenance or replacement while leaving the gearbox housing intact. This extraction approach enables independent servicing of the power coupler mechanism, resolving the contradiction between compact integration and maintenance accessibility by allowing the component to be both integrated during operation and separately removable during maintenance.
Data Source
AI summary
An aircraft powerplant assembly includes a gearbox and a power coupler. The gearbox includes a first engine power transfer apparatus, a second engine power transfer apparatus and an accessory power transfer apparatus. The power coupler is mounted to the gearbox. During a first operating mode, the power coupler is configured to operatively couple the first engine power transfer apparatus to the accessory power transfer apparatus and operatively decouple the second engine power transfer apparatus from the accessory power transfer apparatus. During a second operating mode, the power coupler is configured to operatively couple the second engine power transfer apparatus to the accessory power transfer apparatus and operatively decouple the first engine power transfer apparatus from the accessory power transfer apparatus.