Superposition Gearbox With One-Way Clutches for Accessory Load Split
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Solution Overview
Problem
The existing gas turbine engine designs face inefficiencies due to the loads from the accessory gearbox on the high spool, which reduces engine performance and thermal, transfer, and propulsive efficiencies.
Innovation Solution
The proposed gas turbine engine incorporates a superposition gearbox with one-way mechanical clutches, allowing for selective coupling of the tower shafts to the gear system, and an accessory gearbox driven by the output of the superposition gearbox, optimizing power distribution between the low and high speed spools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the accessory gearbox is directly driven by the high spool through the tower shaft, then the accessory components can be powered, but the loads from the accessory gearbox reduce engine efficiency and performance
Solution Approach 1:
The drive system is segmented into two independent tower shafts: a first tower shaft driven by the low spool and a second tower shaft driven by the high spool. The accessory gearbox is driven by the first tower shaft rather than being directly coupled to the high spool, thereby separating the accessory load from the high spool and eliminating the associated efficiency losses.
2Productivity
If a superposition gearbox with one-way mechanical clutches is used to selectively couple tower shafts, then power distribution is optimized, but the device complexity increases
Solution Approach 1:
The superposition gearbox incorporates one-way mechanical clutches that automatically engage or disengage based on the relative rotational speeds and directions of the two tower shafts. This dynamic mechanism allows the system to adaptively optimize power distribution without requiring complex external control systems, achieving high productivity while managing device complexity through self-regulating mechanical design.
Data Source
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AI summary
A gas turbine engine (20) including a low speed spool (30) including a low pressure compressor (44), a low speed output gear (82) disposed on the low speed spool (30), a high speed spool (32) including a high pressure compressor (52), a high speed output gear (84) disposed on the high speed spool (32), a first tower shaft (76) engaged to the low speed spool (30) at the low speed output gear (82), a second tower shaft (78) engaged to the high speed spool (32) at the high speed output gear (84), and a superposition gearbox (66). The gas turbine engine (20) further including a ring gear shaft (92) coupled to drive the ring gear (108), a ring gear shaft drive gear (90). A low speed spool drive train gear ratio is between 0.5 to 2.0, the low speed spool drive train gear ratio being measured from the low speed output gear (82) to the ring gear shaft drive gear (90).