Compact Aircraft Engine Variable Pitch Propeller Oil Transfer Ring
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Solution Overview
Problem
Compact turboprop engines for small airplanes face challenges in efficiently powering variable pitch propellers due to space constraints within the engine gearbox, making standard hydraulic fluid transfer terminals unsuitable.
Innovation Solution
A compact, modular hydraulic fluid transfer terminal (Transfer Ring) designed to be externally attached to the gearbox or crankcase, featuring a detachable main body with annular hydraulic fluid transfer grooves and ports for efficient oil transfer and pressure management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a standard hydraulic fluid transfer terminal is used within the engine gearbox, then hydraulic pitch control can be provided, but the engine size and weight increase beyond compact requirements
Solution Approach 1:
The hydraulic fluid transfer terminal is extracted from the internal gearbox space and repositioned to the external periphery of the crankcase. This allows the hydraulic pitch control function to be maintained while the terminal no longer occupies valuable internal space, thereby reducing the overall engine size and weight for compact aircraft applications
Solution Approach 2:
The transfer terminal is designed with a planar mounting surface that attaches to the external periphery of the crankcase rather than occupying internal three-dimensional space. This dimensional repositioning from internal volume to external surface area enables compact engine design while maintaining hydraulic functionality
2Volume of moving object
If the hydraulic transfer terminal is positioned externally on the crankcase periphery, then compact engine design is enabled, but providing sufficient oil pressure to the propeller shaft becomes challenging
Solution Approach 1:
The transfer terminal incorporates an annular recess that receives the propeller shaft, creating a nested configuration where the shaft passes through the terminal. This nesting allows direct hydraulic fluid transfer from the external terminal to the internal shaft passages, maintaining oil pressure efficiency despite the external positioning
Solution Approach 2:
The transfer terminal acts as an intermediary component between the external hydraulic fluid source and the internal propeller shaft. It provides a mounting surface for hydraulic connections and facilitates fluid transfer through the shaft, bridging the gap between external positioning and internal function
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 efficient hydraulic pitch control for variable pitch propellers in compact turboprop engines by providing a compact, adaptable, and reliable means of transferring hydraulic fluid, improving engine efficiency and reducing fuel consumption.
Implementation Method 1
The inner wall of the main body is annularly recessed to provide an annular hydraulic fluid transfer groove. At least one hydraulic fluid port is fluidly connected to the hydraulic fluid transfer groove for feeding a hydraulic fluid such as oil in the annular hydraulic fluid transfer groove.
Data Source
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AI summary
The invention relates to a static hydraulic fluid transfer terminal (42) for a hollow propeller shaft (30) that rotates during operation. The hydraulic fluid transfer terminal (42) has a main body (42.1) with an inner wall enclosing a cylindrical free space (42.3). The cylindrical free space (42.3) is configured for receiving the propeller shaft (30). The inner wall of the main body (42.1) is annularly recessed to provide an annular hydraulic fluid transfer groove (42.4). At least one hydraulic fluid port (42.7) is fluidly connected to the hydraulic fluid transfer groove (42.4) for feeding a hydraulic fluid such as oil in the annular hydraulic fluid transfer groove (42.4). The main body (42.1) is composed of at least two separate body parts (42.11, 42.1.2) that are detachably fastened to each other and that are separated along a plane that extends through a longitudinal axis of the cylindrical free space (42.3).