Propeller Blade Pitch Control via Over-Centre Locking Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional turboprop engine systems for controlling propeller blade pitch are complicated by the need for a locking mechanism to resist aerodynamic torque, leading to increased mass, reliability, and space requirements.
Innovation Solution
A system comprising a first annular track with a notch, a second concentric annular track, and an actuating member with a recessed angular portion, where a locking member automatically locks the system when not actuated, allowing for simultaneous release and rotation of the blade pitch by applying a specific torque to the actuating member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is added to resist aerodynamic torque, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The locking mechanism is merged with the actuating member into a single integrated structure. The locking member is housed within the recessed angular portion of the actuating member, eliminating the need for a separate locking mechanism while maintaining the ability to resist aerodynamic torque through the over-centre positioning system.
Solution Approach 2:
The actuating member serves multiple functions: it acts as both the actuator for pitch control and houses the locking mechanism. The locking member simultaneously provides locking functionality and over-centre positioning, allowing the system to perform both actuation and locking functions through a single component structure.
2Reliability
If a locking mechanism is added to resist aerodynamic torque, then the reliability is improved, but the mass increases
Solution Approach 1:
The locking mechanism is merged with the actuating member into a single integrated structure. The locking member is housed within the recessed angular portion of the actuating member, eliminating the need for a separate locking mechanism while maintaining the ability to resist aerodynamic torque through the over-centre positioning system.
3Reliability
If a locking mechanism is added to resist aerodynamic torque, then the reliability is improved, but the volume increases
Solution Approach 1:
The locking member is nested within the recessed angular portion of the actuating member, which itself is integrated into the annular track structure. This nested arrangement allows the locking mechanism to occupy minimal space within the existing structural envelope, eliminating the need for additional external locking components.
4Reliability
If a locking mechanism is added to resist aerodynamic torque, then the reliability is improved, but the ease of manufacture decreases
Solution Approach 1:
The locking mechanism is merged with the actuating member into a single integrated structure. The locking member is housed within the recessed angular portion of the actuating member, eliminating the need for a separate locking mechanism while maintaining the ability to resist aerodynamic torque through the over-centre positioning 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 design simplifies the control system by eliminating the need for a separate locking mechanism, reducing mass, improving reliability, and optimizing space, while enabling efficient pitch adjustment of propeller blades.
Implementation Method 1
a normal over-centre position, wherein it is on the one hand in contact with the second track by being arranged between the two surfaces A1, A2 of the member for actuating, at a distance from the latter, and on the other hand in contact with the notch, position wherein the aerodynamic force is exerted on the blade of the propeller in rotation generates a torque of a given direction on said first track by causing a first contact force F1, on the locking member, of that of the two surfaces B1, B2 of the notch located the farthest upstream in said given direction of the torque, and generating a reaction force R of said second track on said locking member, the first contact force F1 and the reaction force R providing an over-centring of the first and second tracks, rendering the latter integral in rotation
Implementation Method 2
the aerodynamic force is exerted on the blade of the propeller in rotation generates a torque of a given direction on said first track by causing a first contact force F1, on the locking member
Data Source
AI summary
A system for controlling propeller blade pitch in a turboshaft engine, including: a first track connected to a propeller blade, of which the rotation provides for the setting of the incidence of this blade; a second track; a member actuating the first track, arranged between the first and second tracks, and having a recessed angular portion; and at least one locking member provided between the first and second tracks, housed in the recessed angular portion and in the notch. The locking member can occupy a normal over-center position rendering the first and second tracks integral in rotation, and a release position authorizing the displacement in rotation of a unit including the first track, the locking member, and the actuating member.