Variable Pitch Blade Control Assembly Actuation

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Solution Overview

Problem

Existing assemblies for controlling variable pitch blades in aircraft gas turbo-engines face challenges in reducing complexity, compactness, and maintaining control accuracy due to deformation during engine operation, leading to calibration errors and increased aerodynamic drag.

Innovation Solution

An active actuator with a fixed and movable part, utilizing a grooved rod and pivot connections with secondary links, allows for precise control of blade pitch without a VSV box or control rod, incorporating a sealed lubrication system and a secondary casing for protection and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional control ring with driving device is used, then blade pitch control is achieved, but the assembly complexity and number of parts increase

Engineering Contradiction:

Improveblade pitch controlVSAvoidassembly complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines the control ring and actuator into a single integrated assembly where the actuator is mounted directly on the control ring. This merging eliminates the need for separate driving devices and reduces the number of independent components, thereby reducing assembly complexity while maintaining blade pitch control functionality

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The control ring assembly is designed to perform multiple functions: it serves as both the control structure and the mounting base for the actuator, while also providing the rotational control mechanism. This multi-functionality reduces the need for additional dedicated components, simplifying the overall assembly

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If a driving device is mounted tangentially between control ring and casing, then actuation is achieved, but axial deflection and torsion of the ring occur

Engineering Contradiction:

ImproveactuationVSAvoidring stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

Instead of mounting the actuator tangentially between the control ring and casing as in conventional designs, the patent inverts the mounting approach by attaching the actuator directly to the control ring itself. This reversal of the mounting strategy eliminates the transmission of axial deflection and torsion forces to the ring, maintaining ring stability while achieving actuation

Inventive Principle:

Principle #13The other way round (Inversion)

3Volume of moving object

If control components are reduced in size, then aerodynamic drag is minimized, but control accuracy decreases due to deformation

Engineering Contradiction:

Improvecomponent sizeVSAvoidcontrol accuracy

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent segments the control system into modular components with defined interfaces, allowing each component to be optimized for size while maintaining overall control accuracy. The segmented design with precise connection points minimizes deformation effects and allows for compact component sizing without sacrificing control precision

Inventive Principle:

Principle #1Segmentation

4Productivity

If rigid rods are used for control, then movement transmission is efficient, but maintenance increases due to wear

Engineering Contradiction:

Improvemovement transmission efficiencyVSAvoidmaintenance

Core Design Contradiction:

ProductivityVSEase of repair

Solution Approach 1:

The patent replaces traditional rigid mechanical rod connections with a rotational control mechanism that uses angular positioning to transmit control movements. This substitution reduces direct mechanical contact and wear between components, maintaining efficient movement transmission while significantly reducing maintenance requirements

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This solution enhances control accuracy, reduces part count and size, and minimizes deformation-induced errors, resulting in improved mechanical efficiency and reduced maintenance needs while maintaining compactness and aerodynamic performance.

Implementation Method 1

a mobile part (30b) movable parallel to said axis (X), grooved, via a grooved rod, and engaged with pivot connections

Methodology Applied

Scientific EffectMechanical transmission through grooved engagement: Gear

Implementation Method 2

which act on a radial shaft passing through a clevis fixed with the control ring to rotate with it about said axis (X), the radial shaft being mounted radially rotatable with respect to the control ring and the casing

Methodology Applied

Scientific EffectRadial rotation mechanism: Gimbal

Implementation Method 3

incorporating a sealed lubrication system

Methodology Applied

Scientific EffectLubrication: Lubrication

Data Source

PatentUS11015477B2Assembly for controlling variable pitch blades

Publication Date: 2021.05.25 SAFRAN AIRCRAFT ENGINES SAS

AI summary

An assembly for the control of variable pitch blades. The assembly includes a movable part movable parallel to an axis is in engagement with pivot connections which rotate about at least one radial axis fixed with respect to the casing, and which act on a radial shaft, which passes through a clevis fixed with a control ring to rotate with it about said axis. The radial shaft is mounted radially rotating with respect to the control ring and the casing.