Turbomachine Speed Reducer Layout With Dual Electric Machines
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Solution Overview
Problem
Existing turboprop engines face challenges in integrating powerful electrical machines within the mechanical speed reducer without increasing the size and impacting the configuration of nearby components, particularly due to load imbalances and space constraints.
Innovation Solution
The integration of two electrical machines, each driven by an intermediate transmission line, allows for balanced power distribution across two separate lines, regulating load imbalances and maintaining compact dimensions by avoiding radial and axial expansion, with each rotor driven by a pinion of an intermediate line and a stator connected to the turbomachine casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If one or more electrical machines are integrated within the speed reducer housing, then electrical power capacity is improved, but the size of the stator housing and nacelle increases
Solution Approach 1:
The patent divides the single electrical machine function into multiple separate electrical machines (at least two), each with its own rotor and stator. This segmentation allows the electrical power capacity to be increased by adding more machines rather than enlarging a single machine, thereby avoiding the need to increase the overall housing volume proportionally.
Solution Approach 2:
The patent arranges the multiple electrical machines in a distributed configuration within the speed reducer housing, utilizing three-dimensional space more efficiently. The rotors are positioned at different locations (e.g., at different stages of the gear train) and the stators are arranged to surround or adjoin these rotors, effectively using available volume in multiple dimensions rather than expanding in a single direction.
2Power
If multiple electrical machines are added to increase power, then device complexity increases, but integration space remains constrained
Solution Approach 1:
The speed reducer housing serves multiple functions: it houses the mechanical gear train for speed reduction and simultaneously accommodates multiple electrical machines for power generation. The stators are connected to the housing, which acts as a structural support and electrical connection point, eliminating the need for separate mounting structures and reducing overall system complexity.
Solution Approach 2:
The patent merges the mechanical transmission system and electrical power generation system into a single integrated unit. The electrical machines are positioned to utilize the mechanical motion already present in the gear train, with rotors connected to intermediate shafts or gears, thereby combining two functions (mechanical reduction and electrical power generation) without requiring separate spaces or systems.
3Volume of stationary object
If electrical machines are integrated within the speed reducer, then compact design is maintained, but load imbalance between transmission lines worsens
Solution Approach 1:
The patent applies different configurations of electrical machines to different locations within the speed reducer based on local conditions. Each electrical machine is positioned at specific stages of the gear train where the mechanical parameters (speed, torque) are appropriate, and the stators are connected to the housing at locations that facilitate balanced load distribution across the transmission lines.
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 effectively balances loads between transmission lines, increases electrical power capacity without enlarging the stator casing or nacelle, and maintains a compact design, enabling efficient power distribution and reduced axial space requirements.
Implementation Method 1
The turbomachine can be equipped with one or more electric machines 60 designed and configured so as to supply electrical power to the aircraft
Implementation Method 2
There are several types of contact meshing such as with straight, helical or herringbone teeth
Data Source
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AI summary
The invention relates to an assembly for an aircraft turbomachine, comprising a speed reducer (4) having an input pinion (40) connected to a power shaft (2) of the turbomachine and an output pinion (41) connected to a propeller shaft (3) of the turbomachine. According to the invention, the assembly comprises two electric machines (60), each configured to supply electrical power to the propeller shaft or to draw mechanical power from the propeller shaft, each electric machine comprising a rotor (61) and a stator (62), the stator being intended to be connected to a housing of the turbomachine, and in that the speed reducer comprises two substantially parallel intermediate transmission lines (55) configured to transmit torque from the input pinion (40) to the output pinion (41), each rotor (61) being driven in rotation respectively by a pinion of an intermediate line (55).