Planetary Gearbox Switching Between Direct Drive and Speed Change
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Solution Overview
Problem
Existing gas turbine engine gearboxes are limited in their ability to optimize rotational speed ratios for varying flight conditions, often requiring a fixed speed reduction that may not be optimal for all flight regimes, leading to inefficiencies and potential noise issues.
Innovation Solution
A gearbox system with configurable speed change and direct drive configurations, utilizing a planetary gear set with a clutch and brake mechanism to selectively engage components, allowing for adjustable rotational speed ratios between input and output shafts, enabling increased power or reduced propeller speed as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed speed reduction ratio is used in the gearbox, then the structure is simple and reliable, but the performance cannot be optimized for varying flight conditions
Solution Approach 1:
The patent applies the dynamics principle by making the gearbox configuration changeable during operation. The system transitions from a fixed single-ratio gearbox to a variable configuration gearbox that can switch between direct drive and speed reduction modes using a reversible clutch. This allows the gearbox to adapt its speed ratio dynamically based on flight conditions, resolving the contradiction between adaptability and structural simplicity.
2Power
If a single fixed ratio is used, then the device complexity is low, but the power delivery and noise performance are suboptimal for different flight regimes
Solution Approach 1:
The patent applies the universality principle by designing a gearbox that performs multiple functions: it can operate in direct drive mode for certain flight conditions and in speed reduction mode for others. The reversible clutch enables the same gearbox structure to serve different functional purposes, allowing optimal power delivery across varying flight regimes without requiring multiple separate gearboxes.
3Object-affected harmful factors
If a fixed speed reduction gearbox is used, then manufacturing is simpler, but noise reduction performance is limited
Solution Approach 1:
The patent applies the dynamics principle to noise reduction by enabling the gearbox to switch between direct drive and speed reduction configurations. This dynamic capability allows the system to select the optimal configuration for noise reduction in different flight conditions, achieving better noise performance without significantly complicating the manufacturing process, as the same basic gearbox structure is used in both modes.
Data Source
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AI summary
A gearbox for an aircraft engine including first and second gears in driving engagement through planet gears supported by a carrier. Selective application of a brake and a blocking member permit operation in a speed change configuration and a direct drive configuration.