Off-Axis Propeller Gear Layout for Larger Turbine Propellers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing aircraft turbine engines face challenges in increasing propeller diameter while maintaining ground clearance and minimizing weight and structural changes, as larger propellers require bulkier engines and complex repositioning solutions.
Innovation Solution
The integration of a mechanical reduction gear with a sun gear connected to the turbine shaft and a ring gear with internal toothing connected to the propeller shaft, allowing for parallel and offset axes of rotation, which eliminates the need for a separate power transmission system and optimizes engine size and mechanical moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the propeller diameter is increased to increase the bypass ratio, then the propulsion efficiency is improved, but the engine bulk and weight increase
Solution Approach 1:
The patent offsets the propeller axis from the turbine axis in the radial direction, transitioning from a coaxial configuration to an off-axis configuration. This dimensional change allows the propeller to achieve a larger diameter without increasing the engine's axial length, thereby increasing the bypass ratio without proportionally increasing engine bulk and weight
2Productivity
If the propeller diameter is increased to increase the bypass ratio, then the propulsion efficiency is improved, but the engine radial bulk increases
Solution Approach 1:
By offsetting the propeller axis radially from the turbine axis, the patent enables the propeller to extend further in the radial direction without requiring the entire engine structure to expand. The off-axis configuration allows the propeller blades to sweep a larger area while the engine casing maintains a more compact radial footprint
3Adaptability or versatility
If a separate power transmission system is added to enable off-axis configuration, then the propeller can be offset from the turbine, but the device complexity increases
Solution Approach 1:
The patent integrates the power transmission function directly into the reduction gear assembly by meshing the sun gear with the turbine shaft and the ring gear with the propeller shaft. This merging of functions eliminates the need for a separate power transmission system, reducing device complexity while maintaining the off-axis configuration capability
Solution Approach 2:
The reduction gear assembly serves multiple functions: it provides mechanical reduction, enables the off-axis configuration through its sun-gear-ring-gear structure, and directly transmits power from the turbine to the propeller. This multi-functionality eliminates the need for additional dedicated power transmission components
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
This configuration enables a larger propeller diameter with reduced engine bulk and weight, while effectively managing mechanical moments, allowing for more compact and efficient turbine engine design.
Implementation Method 1
a mechanical reduction gear coupled to the turbine shaft and configured to drive in rotation the propeller shaft, the reduction gear comprising a sun gear, a ring gear and at least two planet gears meshed with the sun gear and the ring gear
Data Source
AI summary
An aircraft turbine engine includes a turbine shaft having a first axis of rotation, a propulsion propeller having a second axis of rotation parallel to and spaced from the first axis, and a mechanical reduction gear coupled to the turbine shaft and rotating the propeller. The reduction gear has a sun gear connected to the turbine shaft, a ring gear, and at least two planet gears, each including a first external toothing that is meshed with an external toothing of the sun gear. A second external toothing is located within the ring gear and is meshed with an internal toothing of the ring gear.