Stack Nut Phonic Wheel Assembly for Turbine Shaft Speed Sensing
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Solution Overview
Problem
Existing sensor systems for gas turbine engines, particularly those using phonic wheels, face limitations in accurately measuring rotational velocity and efficiently managing lubricant delivery, leading to potential lubricant churning and reduced accuracy due to windage effects.
Innovation Solution
The integration of a castellated periphery phonic wheel within a stack nut, which includes a lubricant scoop and passages, allows for precise measurement of rotational velocity by a sensor system that measures fluctuations in the magnetic field induced by the castellated periphery, while also improving lubricant delivery by isolating windage from the lubricant injection and collection areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a phonic wheel is integrated into the stack nut for rotational velocity measurement, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines the phonic wheel with the stack nut into a single integrated component. The castellated periphery is formed directly on the stack nut body, eliminating the need for a separate phonic wheel component. This merging approach maintains measurement precision while reducing overall device complexity through component consolidation.
Solution Approach 2:
The stack nut is designed to serve multiple functions simultaneously: it provides structural support for the bearing assembly, enables rotational velocity measurement through its castellated periphery, and facilitates lubricant delivery through integrated passages. This multi-functionality reduces the total number of components needed in the system.
2Productivity
If lubricant passages are integrated into the stack nut, then lubricant delivery efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The lubricant passages are integrated directly into the stack nut body, combining the lubricant delivery function with the structural component. This integration ensures proper lubricant flow paths are maintained while reducing the number of separate lubrication system components.
Solution Approach 2:
The passages are pre-formed as part of the stack nut manufacturing process, establishing the lubricant delivery paths before assembly. This preliminary formation of passages ensures proper geometry and positioning without requiring additional post-assembly modifications.
3Measurement precision
If the castellated periphery is formed on the stack nut, then rotational velocity measurement accuracy is improved, but ease of manufacture decreases
Solution Approach 1:
The castellated periphery is formed by creating discrete indentations or teeth around the stack nut circumference. This segmentation approach allows the complex shape to be manufactured through standardized machining operations rather than requiring complex tooling, balancing measurement accuracy with manufacturability.
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 solution enhances the accuracy of rotational velocity measurement, reduces lubricant churning, and ensures effective lubricant delivery, thereby improving the overall performance and reliability of the turbine engine by integrating the phonic wheel with the stack nut and lubricant management system.
Implementation Method 1
The sensor is configured to measure fluctuations in a magnetic field induced by the castellated periphery during rotation of the rotating assembly about the axis
Data Source
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AI summary
An assembly (10) for a turbine engine includes a rotating assembly (14) and a sensor (152). The rotating assembly (14) is configured to rotate about an axis (36). The rotating assembly (14) includes an engine shaft (24; 184, 185, 186) and a stack nut (30) threaded onto the engine shaft (24..186). The stack nut (30) includes a castellated periphery (102). The sensor (152) is configured to measure fluctuations in a magnetic field induced by the castellated periphery (102) during rotation of the rotating assembly (14) about the axis (36).