Coupled Planetary Gearbox With Overlapping Shift Speeds
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Solution Overview
Problem
Modern aircraft engines face a challenge in meeting increasing electric power demands due to the limited power extraction potential of high pressure spools, necessitating an efficient transmission system that can convert wide input speed ratios into narrower output speed ratios for aircraft accessories.
Innovation Solution
A coupled planetary gearbox transmission system is employed, featuring epicyclical gear sets and a plurality of clutches that shift between closed and opened states to generate overlapping transmission speeds, allowing the output shaft to be engaged in parallel and decoupled from specific gear components, thereby converting a large input speed ratio range into a smaller output speed ratio range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a transmission system is designed to convert wide input speed ratios into narrower output speed ratios, then the adaptability to meet increasing electric power demands is improved, but the device complexity increases due to the need for multiple epicyclical gear sets and clutches
Solution Approach 1:
The patent combines two epicyclical gear sets into a single integrated transmission system where the first and second planetary gear sets share common components (input shaft, output shaft, clutches). This merging allows the system to achieve multiple transmission ratios and adapt to varying power demands while avoiding the complexity of completely separate gear systems.
Solution Approach 2:
The transmission system is designed with multi-functional components that can serve multiple purposes. The clutches can engage different gear sets to provide various transmission ratios, and the overlapping speed ranges allow the system to operate in multiple modes, making it universally adaptable to different electric power demand scenarios.
2Reliability
If multiple clutches are used to generate overlapping transmission speeds, then the smoothness of shifting is improved, but the device complexity increases
Solution Approach 1:
The patent designs the clutch system with predetermined engagement sequences and overlapping speed ranges that are established before operation. The control system is configured to engage clutches in specific sequences, ensuring smooth transitions between transmission ratios without sudden shocks or disruptions to the power flow.
3Productivity
If the transmission system engages the output shaft in parallel through multiple clutches, then the productivity in power delivery is improved, but the difficulty of controlling the system increases
Solution Approach 1:
The transmission system incorporates a control system that monitors the engagement state of multiple clutches and adjusts their operation based on feedback signals. This feedback mechanism ensures that the parallel engagement of clutches maintains optimal power delivery while preventing conflicts or improper engagement sequences that could compromise system reliability.
Data Source
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AI summary
Transmission, including: an input shaft (220); an output shaft (230); a gear system (330) connected between the input shaft (220) and the output shaft (230), the gear system (330) including: a first epicyclical gear set (330a) that includes a first ring gear (340) coupled to the input shaft (220), a first sun gear (350), a first planetary gear set (360), and a first planetary carrier (370) connected to the first planetary gear set (360); and a second epicyclical gear set (330b) that includes a second ring gear (380), a second sun gear (390), a second planetary gear set (400), and a second planetary carrier (410) connected to the second planetary gear set (400), wherein: the input shaft (220) is coupled to the first ring gear (340) and the second planetary carrier (410); and the first planetary carrier (370) is coupled to the second ring gear (380); and clutches (420) that engage the first epicyclical gear set (330a) and the second epicyclical gear set (330b), the clutches (420) shifting the transmission to generate overlapping transmission speeds.