Aircraft Engine Torque Measurement Using Frustoconical Alignment
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Solution Overview
Problem
Existing torque measurement systems in aircraft propulsion systems, such as turboprop and turboshaft engines, suffer from inaccuracies due to relative radial movement between toothed wheels caused by bending moment loads, leading to incorrect torque measurements.
Innovation Solution
The implementation of frustoconical elements on the loaded and reference shafts, which are angled relative to the central axis and abut with complementary surfaces, limits relative radial displacement and minimizes unwanted movement, ensuring accurate torque measurement by maintaining precise tooth spacing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional torque measurement systems use toothed wheels mounted on loaded and reference shafts, then torque can be measured by detecting relative rotational displacement, but bending moment loads cause relative radial movement between toothed wheels leading to measurement inaccuracies
Solution Approach 1:
The patent introduces frustoconical elements as intermediary components between the toothed wheels and the shafts. These elements act as mediators that transform the relationship between the rotating shafts and the measurement teeth, converting radial movement issues into axial positioning problems that can be more stably controlled through the frustoconical geometry and spring mechanisms.
Solution Approach 2:
The patent changes the geometric parameters of the toothed wheel mounting system by introducing frustoconical elements with specific angles and dimensions. By altering the shape from traditional cylindrical to frustoconical geometry, the system changes how forces are distributed and how positional stability is achieved, allowing for better compensation of radial movements through the inclined surfaces.
2Device complexity
If toothed wheels are directly mounted on shafts for torque measurement, then the system structure is simple, but bending moments cause incorrect torque measurements due to radial displacement
Solution Approach 1:
The patent segments the toothed wheel assembly into separate functional components: the toothed wheel itself, the frustoconical mounting elements, and the spring mechanisms. This segmentation allows each component to be optimized for its specific function while working together to achieve both structural simplicity and measurement precision, with the frustoconical elements providing a compact solution for maintaining tooth alignment.
Solution Approach 2:
The patent employs frustoconical (curved) surfaces instead of flat or cylindrical mounting surfaces. The curved geometry of the frustoconical elements provides inherent stability by distributing loads along inclined surfaces, which naturally resists radial displacement while maintaining a relatively simple overall structure. The curved surfaces enable self-centering effects that improve measurement accuracy without adding complex active control mechanisms.
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 system reduces torque measurement errors by minimizing relative radial displacement between toothed wheels, providing more accurate torque readings despite bending moment loads.
Implementation Method 1
a frustoconical element located proximate the input end of the loaded shaft, the frustoconical element comprising an annular body radially disposed between the loaded shaft and the torque reference tube and being mounted to one of the loaded shaft and the torque reference tube for rotation therewith, the frustoconical element including a frustoconical surface facing towards the other of the loaded shaft and the torque reference tube and abutting a complementary running surface, wherein the frustoconical surface of the frustoconical element and the complementary running surface rotate relative to each other and define a contact interface
Data Source
AI summary
A torque measurement system for an aircraft propulsor including a reduction gearbox includes generally a first toothed wheel mounted to a loaded shaft, a second toothed wheel mounted to a torque reference tube radially spaced apart from the loaded shaft and concentric therewith, and a torque probe located proximate the first and second toothed wheels. A frustoconical element is located proximate an input end of the loaded shaft, the frustoconical element having an annular body radially disposed between the loaded shaft and the torque reference tube and being mounted for rotation with one of the two. The frustoconical element includes a frustoconical surface that abuts a complementary running surface. The frustoconical surface of the frustoconical element and the complementary running surface rotate relative to each other and define a contact interface, the contact interface being annular and oriented at an angle relative to the central axis.