Integrated Thrust Reverser and VAFN Actuator Design

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Solution Overview

Problem

The existing separate actuators for variable area fan nozzle (VAFN) and thrust reverser cowls in aircraft turbine engines result in significant cost, power, and weight implications due to their large stroke requirements.

Innovation Solution

An integrated actuator system that combines the thrust reverser and VAFN actuation using a ballscrew shaft with ballnuts and a locking mechanism, allowing independent movement of the cowls while sharing components to reduce the overall size and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If separate actuators are used for VAFN and thrust reverser cowls, then independent control of each cowl is achieved, but weight and cost increase significantly

Engineering Contradiction:
Improveindependent control capabilityVSAvoidactuator weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent combines two separate actuator systems into a single integrated actuator that controls both the VAFN cowl and thrust reverser cowl. The integrated actuator uses a common drive mechanism with a shaft and two ball nuts to independently position each cowl, eliminating the weight and cost of having two separate actuators while maintaining independent control capability through selective engagement of each ball nut.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated actuator serves multiple functions: it controls both the VAFN cowl and thrust reverser cowl, provides independent positioning for each cowl, and includes a locking mechanism for safety. This multi-functional design replaces what would traditionally require two separate actuators, reducing overall system weight and cost while maintaining full operational independence of each cowl.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Length of moving object

If separate actuators are used for VAFN and thrust reverser cowls, then full stroke movement for each cowl is achieved, but device complexity and cost increase

Engineering Contradiction:
Improveactuator strokeVSAvoidactuator system complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent merges two separate actuator systems into one integrated actuator with a common shaft and two ball nuts. This shared mechanical structure reduces the overall complexity compared to two independent actuators, while still providing the full stroke movement capability for each cowl through selective engagement of each ball nut on the common shaft.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If separate actuators are used for VAFN and thrust reverser cowls, then complete functionality for each system is achieved, but power consumption increases

Engineering Contradiction:
Improvesystem functionalityVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The integrated actuator provides complete functionality for both VAFN and thrust reverser systems through a single multi-functional device. By using a common drive mechanism with selective ball nut engagement, it maintains full operational capability for each system while reducing power consumption compared to two separate actuators operating independently.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 integrated actuator system reduces the weight and cost of the engine by eliminating the need for separate actuators, enabling efficient and independent control of both thrust reverser and VAFN cowls, thereby improving engine efficiency and reducing operational complexity.

Implementation Method 1

A common drive mechanism includes a shaft and two ball nuts, each ball nut being engageable with the shaft

Methodology Applied
Scientific EffectScrew: Screw

Data Source

PatentEP2617978B1Integrated thrust reverser actuator and variable area fan nozzle actuator
Publication Date: 2018.12.12 HAMILTON SUNDSTRAND CORP
  • EP2617978B1 patent drawingFigure 1
  • EP2617978B1 patent drawingFigure 2
  • EP2617978B1 patent drawingFigure 3

AI summary

An integrated thrust reverser and variable area fan nozzle actuator (100) includes a ballscrew shaft (120) having a first ballnut (122) and a second ballnut (130). The second ballnut (130) is fastened to a first translatable object. A bearing (134) is affixed to the ballscrew shaft (120) between the first ballnut (120) and the second ballnut (122). A second translatable object is coupled to the bearing (134). A drive mechanism (160) is operably coupled to the first ballnut (122) for rotation and a locking mechanism (150) selectively couples the ballscrew shaft (120) to the first ballnut (122).