Dual-Ratio Planetary Power Drive for Slat and Flap Load Matching

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional power drive units for aircraft flight control high lift systems are limited by a single gear ratio reduction, which cannot meet the significant variation in torque and speed requirements for both slats and flaps, leading to inefficiencies in power transmission.

Innovation Solution

A power drive unit with a gear ratio mechanism that includes multiple gear ratios, allowing selection based on the specific component being driven, utilizing a differential and clutch system with planetary gear sets and one-way clutch mechanisms to provide distinct torque and speed outputs for slats and flaps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single gear ratio reduction is used in the power drive unit, then the device complexity is reduced, but the adaptability to meet different torque and speed requirements for slats and flaps deteriorates

Engineering Contradiction:

Improvegear ratio mechanismVSAvoidtorque and speed output

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements a dual gear ratio mechanism that dynamically switches between two different gear ratios (first gear ratio for slats, second gear ratio for flaps) based on the specific component being driven. This dynamic adaptation allows the power drive unit to optimize torque and speed output for each component's specific performance requirements, resolving the contradiction between device complexity and adaptability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The power drive unit is designed with multi-functionality to serve both slats and flaps with different performance characteristics through a single integrated mechanism. The dual gear ratio system enables one power drive unit to universally accommodate the significantly different torque and speed requirements of both components, eliminating the need for separate drive units while maintaining adaptability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If a single gear ratio is used, then the manufacturing cost is reduced, but the power transmission efficiency for both slats and flaps deteriorates

Engineering Contradiction:

Improvepower drive unitVSAvoidpower transmission

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent changes the gear ratio parameter based on the specific component being driven. By selecting the first gear ratio for slats and the second gear ratio for flaps, the system optimizes power transmission efficiency for each component's specific torque and speed requirements, minimizing energy loss while maintaining manufacturing feasibility through a integrated dual-ratio mechanism.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3279508B1Power drive unit with dual gear ratio mechanism

Publication Date: 2021.04.28 HAMILTON SUNDSTRAND CORP

Figure 1
Figure 2
Figure 3

AI summary

A gear ratio mechanism (50) includes an input shaft (60), a first planetary gear set (62), a second planetary gear set (64), and a carrier link (82) associated with an output shaft. The carrier link (82) is configured to couple the first planetary gear set (62) and the second planetary gear set (64). The carrier link (82) is selectively driven by the first planetary gear set (62) and the second planetary gear set (64) in response to rotation of the input shaft (60).