Planetary Gearbox Torque Sensing via Ring Gear Axial Deflection
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Solution Overview
Problem
Current aircraft propulsion systems with speed-changing gearboxes lack accurate torque measurement capabilities, which are essential for controlling rotational loads and optimizing propulsion efficiency.
Innovation Solution
A torque sensor assembly integrated with a planetary gear assembly in aircraft propulsion systems, featuring a sun gear, planet gears, and ring gears, generates an output signal corresponding to axial deflection, allowing a controller to calculate torque applied to the output shaft and control rotation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a torque sensor assembly is integrated into the planetary gear assembly, then torque measurement precision is improved, but device complexity increases
Solution Approach 1:
The torque sensor assembly is integrated directly into the planetary gear assembly, merging the torque measurement function with the existing gear structure. The sensor assembly includes a piston that contacts the second ring gear and a pressure sensor that measures fluid pressure in a cavity, combining mechanical and sensing elements into a unified structure that eliminates the need for separate torque measurement devices.
Solution Approach 2:
The planetary gear assembly serves multiple functions: it provides speed reduction for the propeller and simultaneously enables torque measurement through the integrated sensor assembly. The fluid cavity and piston mechanism serve both as part of the gear operation and as the sensing mechanism for torque measurement, allowing one structure to fulfill multiple roles.
2Productivity
If torque measurement capabilities are added to the gearbox, then propulsion efficiency control is improved, but manufacturing complexity increases
Solution Approach 1:
The torque sensor assembly is designed as a modular unit with distinct components including a piston, fluid cavity, and pressure sensor that can be manufactured separately and then integrated into the planetary gear assembly. This segmentation allows each component to be manufactured using standard processes and assembled into the final torque measurement system.
Solution Approach 2:
The torque measurement mechanism utilizes fluid pressure within a closed cavity, where the pressure sensor measures the pressure of fluid acting on the piston. This pneumatic/hydraulic approach provides accurate torque measurement through pressure sensing, which is a well-established and manufacturable technology that avoids complex mechanical linkages.
3Measurement precision
If axial deflection measurement is used to determine torque, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces direct mechanical measurement of axial deflection with a fluid pressure-based measurement system. Instead of using complex mechanical displacement sensors to measure the piston's axial movement, the system uses fluid pressure sensing, which is simpler and more accurate. The pressure sensor measures the pressure of fluid in the cavity, which correlates directly to the axial deflection and thus the torque being measured.
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
Enables precise torque measurement and control of rotational loads, enhancing propulsion efficiency and system performance by accurately determining torque applied to the propeller, thereby optimizing aircraft propulsion.
Implementation Method 1
The pressure sensor may be connected in fluid communication with the fluid cavity
Implementation Method 2
The piston may be disposed in contact with the second ring gear. The piston may be configured for axial translation relative to the housing
Data Source
AI summary
An assembly for an aircraft propulsion system includes a planetary gear assembly, a torque sensor, and a controller. The planetary gear assembly includes a sun gear, a plurality of planet gears, a first ring gear, and a second ring gear. Each planet gear of the plurality of planet gears includes a main gear, a first lateral gear, and a second lateral gear. The main gear is engaged with the sun gear, the first lateral gear is engaged with the first ring gear, and the second lateral gear is engaged with the second ring gear. The torque sensor assembly contacts the second ring gear. The torque sensor assembly is configured to generate an output signal corresponding to an axial deflection of the second ring gear. The controller is configured to calculate a torque applied to the output shaft by the planetary gear assembly using the output signal.