Phasing Gearbox for Precise Gas Turbine Spool Balancing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for balancing gas turbine engine spools require extensive disassembly and provide imprecise rotational information due to the use of optical indicators, which is time-consuming and inefficient.
Innovation Solution
A phasing gearbox system with a gear assembly and accessory gearbox that allows for the determination of shaft position and rotational speed without disassembly, using a phasing gearbox with inverse gear ratios and position indicators on a circular member, enabling precise balancing through minimal setup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical indicators are used to measure rotational information, then measurement capability is provided, but extensive disassembly is required and measurement precision is insufficient
Solution Approach 1:
The patent introduces a phasing gearbox as an intermediary device between the accessory gearbox and the measurement system. This phasing gearbox contains a circular member with position indicators that can be observed through a viewing port, serving as a mediator that transmits rotational position information without requiring direct optical access to the spool. This resolves the contradiction by providing precise measurement capability while avoiding extensive disassembly.
Solution Approach 2:
The patent creates a visual copy of the rotational position information by placing position indicators on a circular member within the phasing gearbox. This circular member rotates in sync with the accessory gearbox, creating a replicated representation of the rotational state that can be observed externally through the viewing port. This copying approach enables precise measurement without requiring direct access to the actual spool.
2Productivity
If optical indicators are positioned within the core with line of sight access, then rotational information can be measured, but the process requires ten to fifteen man-hours of disassembly
Solution Approach 1:
The phasing gearbox serves as an intermediary that provides external access to rotational position information through a viewing port. Instead of requiring disassembly to position optical indicators within the core, the system uses the phasing gearbox as a mediator that translates internal rotational motion into externally observable position indicators, dramatically reducing the time required from ten to fifteen man-hours to minimal setup time.
Solution Approach 2:
The patent moves the measurement interface from the internal three-dimensional space within the core to an external two-dimensional viewing plane through the viewing port. The circular member with position indicators presents rotational information on a flat, externally accessible surface, allowing measurement without penetrating into the engine core and eliminating the need for extensive disassembly.
3Measurement precision
If optical devices are used for measurement, then rotational information is obtained, but the output signal is not clean and sharp enough for precise balancing
Solution Approach 1:
The patent uses visual position indicators on the circular member that provide clear, distinct visual markers for different rotational positions. These indicators create sharp, well-defined visual signals that are easy to detect and interpret, producing clean output signals suitable for precise balancing operations. The visual contrast and clarity of the position indicators eliminate the signal quality problems associated with conventional optical devices.
Data Source
AI summary
A gas turbine engine includes a compressor, a turbine, and an engine shaft coupled to the compressor and the turbine; a gear assembly including a driveshaft and an accessory gearbox, the driveshaft rotatable by the engine shaft and the accessory gearbox rotatable by the driveshaft, the accessory gearbox including an AGB output, and the gear assembly defining a first overall gear ratio between the engine shaft and the AGB output; and a phasing gearbox coupled to the accessory gearbox and including a PGB output, and the phasing gearbox defining a second overall gear ratio between the AGB output of the accessory gearbox and the PGB output, wherein the second overall gear ratio is an inverse of the first overall gear ratio.