Windmill Lubrication Gear Train for Bidirectional Fan Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engines face challenges in lubricating gear reductions during windmilling operations, where the fan rotor can rotate in either direction, requiring a compact gear train that can efficiently supply oil to the gear reduction system under various conditions, including windmilling in both forward and reverse directions.
Innovation Solution
A compact gear train design incorporating sprag clutches and a specific gear configuration that allows the oil pump to operate in either direction of fan rotor rotation, ensuring continuous lubrication to the gear reduction, even during windmilling, by using forward and reverse input gears connected through clutches to drive the pump gear, allowing for efficient packaging and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gear train is designed to supply lubrication during windmilling in either direction, then lubrication reliability is improved, but device complexity increases
Solution Approach 1:
The gear train is segmented into separate forward-rotation gear components and reverse-rotation gear components. Each segment is responsible for engaging only during its designated rotation direction, allowing the system to handle bidirectional windmilling through modular, direction-specific subassemblies rather than a single complex mechanism.
Solution Approach 2:
The gear train incorporates dynamic engagement characteristics where forward-rotation gears and reverse-rotation gears selectively engage based on the direction of fan rotor rotation. This dynamic behavior allows the system to automatically adapt to bidirectional windmilling conditions without requiring a fixed, overly complex mechanism for both directions simultaneously.
2Adaptability or versatility
If a gear train is designed to accommodate bidirectional windmilling, then adaptability is improved, but package space increases
Solution Approach 1:
The gear train uses segmented forward- and reverse-rotation gear components that can be arranged in a compact configuration. By dividing the bidirectional lubrication function into separate directional segments, the design achieves adaptability without requiring a large package space that would result from a single monolithic bidirectional mechanism.
Solution Approach 2:
The gear train employs universal gear components that can engage in both forward and reverse rotation directions through the selective engagement of forward-rotation gears and reverse-rotation gears. This multi-functionality allows a single gear train assembly to handle bidirectional windmilling, reducing the need for separate mechanisms and thereby minimizing package space.
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 gear train effectively supplies lubrication to the gear reduction during windmilling in either direction, ensuring the engine's operation is not compromised, allowing for extended windmilling periods and compact packaging, thus addressing the need for continuous lubrication under adverse conditions.
Implementation Method 1
the first and second clutches are sprag clutches
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A gas turbine engine (20) includes a fan (42) driven by a fan drive turbine (46) through a gear reduction (48). An oil pump (112) is driven by a main input gear (100), and the main input drive gear (100) rotates when the fan rotor (42) rotates. A gear train (99) is intermediate the main input gear (100) and the oil pump (112). The gear train (99) includes a forward input gear (102) and a reverse input gear (104), each driven by the main input gear (100). The forward input gear (102) drives a forward pinion gear (103) through a forward clutch (101) and the reverse input gear (104) drives a reverse pinion gear (107) through a reverse clutch (105). The forward clutch (101) transmits rotation from the forward input gear (102) to the forward pinion gear (103) when the fan (42) is rotating in a first direction, and does not transmit rotation from the forward input gear (102) to the forward pinion gear (103) when the fan (42) is rotating in a second opposed direction. The reverse clutch (105) transmits rotation from the reverse input gear (104) to the reverse pinion gear (107) when the fan (42) is rotating in the second opposed direction, and does not transmit rotation from the reverse input gear (104) to the reverse pinion gear (107) when the fan (42) is rotating in the first direction. One of the forward and reverse pinion gears (103,107) drive a pump drive gear (106), to, in turn, drive the pump (112).