Turboshaft Gearbox Torque Tube Stage for Compact Torque Sensing
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Solution Overview
Problem
Existing turboshaft engines face challenges in minimizing engine length while effectively measuring torque, as phonic wheel systems on power turbine or gearbox output shafts are not ideal for reducing axial length or incorporating a clutch.
Innovation Solution
A combined speed ratio stage and twist-based torque measuring system with a torque and reference tube assembly connected by free, non-piloted splines, supported by bearings, and a twist-based sensor system to measure relative rotation between the tubes, allowing for reduced engine length and simplified gearbox design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a phonic wheel system is installed on the power turbine shaft or gearbox output shaft to measure torque, then torque measurement is achieved, but the engine length and bearing span cannot be minimized
Solution Approach 1:
The patent combines the torque measurement function with the speed ratio stage by integrating the torque tube and reference tube assembly directly into the gearbox structure. The torque tube is coupled to the input shaft and the reference tube to the output shaft, merging torque measurement with the existing speed reduction mechanism, thereby eliminating the need for separate phonic wheel systems and reducing overall engine length
Solution Approach 2:
The reference tube is nested within the torque tube assembly, with the reference tube positioned concentrically inside the torque tube. This nested configuration allows both tubes to share the same space, minimizing the radial and axial dimensions required for torque measurement while maintaining measurement accuracy
2Measurement precision
If a phonic wheel system is used for torque measurement, then torque data is obtained, but additional features like clutch systems cannot be incorporated on the output shaft
Solution Approach 1:
The output shaft is designed to serve multiple functions: it supports the reference tube for torque measurement, transmits rotational motion, and provides mounting capability for additional features such as clutch systems. The reference tube is positioned and configured to not interfere with these additional features, allowing the output shaft to fulfill multiple roles simultaneously
3Stability of the object's composition
If the torque tube and reference tube are rigidly connected, then structural stability is improved, but relative rotation measurement becomes impossible
Solution Approach 1:
The connection between the torque tube and reference tube is designed to be dynamically adjustable - rigid enough to maintain structural stability during operation, but with controlled flexibility that allows relative rotation between the two tubes. This relative rotation is precisely measured by sensors to determine torque, while the overall structure remains stable under load
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 achieves a reduced overall powerplant length, shorter bearing span, and enables additional features like a clutch system on the output shaft, while maintaining effective torque measurement.
Implementation Method 1
a twist-based sensor system to measure twist of the torque tube
Data Source
AI summary
A turboshaft engine is provided and includes a turbine shaft, an output shaft and a combined speed ratio stage and torque measuring system. The combined speed ratio stage and torque measuring system includes a rigid assembly, a sensor system and first and second bearings. The rigid assembly includes a torque tube, a first gear-speed ratio stage to transmit gear-reduced or gear-increased torque from the turbine shaft and to the torque tube and a second gear-speed ratio stage to transmit gear-reduced or gear-increased torque from the torque tube to the output shaft. The sensor system measures twist of the torque tube. The first and second bearings support the rigid assembly.