Dual-Speed Planetary Gearbox With Ring Lock for Variable Propulsor Speed
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Solution Overview
Problem
Gas turbine engines with single-speed propulsor systems face inefficiencies, particularly in applications requiring varying operational conditions such as vertical takeoff and land aircraft.
Innovation Solution
A planetary gear system with a ring lock mechanism that allows the propulsor to operate at two distinct speeds by selectively engaging different ring gears, enabling efficient speed adjustment based on operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-speed propulsor system is used, then the device complexity is reduced, but the efficiency is worsened under varying operational conditions
Solution Approach 1:
The patent implements a dual-speed planetary gear system that allows the propulsor to dynamically switch between two operating speeds (first speed and second speed) based on operational conditions. The ring lock mechanism enables selective engagement of different ring gears, transforming the static single-speed system into a dynamic multi-speed system that adapts to varying flight conditions, thereby improving efficiency without excessive complexity
Solution Approach 2:
The invention changes the speed parameter of the propulsor by providing two distinct speed settings through the planetary gear system. The ring lock mechanism selectively engages first and second ring gears to change the gear ratio, allowing the propulsor to operate at an first speed under first conditions and an second speed under second conditions, optimizing efficiency across different operational scenarios
2Use of energy by moving object
If a dual-speed planetary gear system is implemented, then the efficiency under varying conditions is improved, but the device complexity increases
Solution Approach 1:
The planetary gear system serves multiple functions: it provides gear reduction, enables dual-speed operation, and allows selective engagement of different ring gears through the ring lock mechanism. This multi-functional design achieves efficiency improvement across varying conditions while consolidating multiple functions into a relatively compact structure, mitigating the complexity increase
Solution Approach 2:
The patent employs a planetary gear arrangement where planet gears are nested around a sun gear, and ring gears enclose the planet gears. This nested configuration allows the dual-speed mechanism to be integrated within a compact volume, reducing the space and structural complexity required compared to equivalent conventional gear systems
3Productivity
If the ring lock mechanism selectively engages different ring gears, then the propulsor speed optimization is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The ring lock mechanism acts as an intermediary component that selectively engages with either the first ring gear or the second ring gear. This intermediary design provides a controlled interface for speed selection, allowing the system to achieve propulsor speed optimization while managing manufacturing precision requirements through a dedicated engagement mechanism rather than direct gear-to-gear precision requirements
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 dual-speed operation enhances efficiency by optimizing propulsor speed according to specific conditions, such as idle or high-thrust scenarios, thereby improving overall engine performance.
Implementation Method 1
The turbine shaft drives the propulsor input shaft through a gear reduction. The gear reduction is a planetary gear system having a sun gear rotating with the turbine shaft and engaging and driving a plurality of planet gears.
Implementation Method 2
The planet gears rotate with a gear carrier. The gear carrier drives the propulsor input shaft.
Implementation Method 3
A ring lock has a pair of gear tooth sets. A first of the gear tooth sets on the ring lock selectively engage with a first ring gear tooth set and a second of the gear tooth sets on the ring lock selectively engageable with a second ring gear tooth set. The ring lock is constrained against rotation
Implementation Method 4
the sync idler moves with the ring lock and has a friction clutch that allows it to adjust a position relative to the ring lock during movement
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A gear carrier (108) drives an aircraft propulsor (90). Two ring gears (110, 112) engage with respective tooth locations (107, 109) on planet gears (106). A first gear tooth set (129) on a ring lock (124) selectively engages with a first ring gear (112) and a second gear tooth set (128) on the ring lock (124) selectively engages with a second ring gear (110). When the first gear tooth set (129) on the ring lock (124) engages the first ring gear (112), rotation of the first ring gear (112) stops, and the planet gears (106) drive the carrier (108) at a first speed. When the second ring lock gear tooth set (128) engages the second ring gear (110), rotation of the second ring gear (110) stops and the planet gears (106) drive the carrier (108) at a second speed which is different than the first speed.