Contra-rotating Propeller Pitch Control via Single Actuator
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Solution Overview
Problem
Existing systems for changing the pitch of contra-rotating propellers in aircraft turbo-engines face reliability issues due to sealing problems, bulkiness, and high mass, particularly with fluidic control systems and multiple actuators.
Innovation Solution
A system utilizing a linear actuator aligned axially with one propeller, connected via an intermediate ball bearing and articulated mechanisms to transmit movement and control the orientation of both propellers, reducing the need for multiple actuators and minimizing weight and bulkiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fluidic control systems with multiple actuators are used to change propeller pitch, then the propeller orientation can be adjusted, but sealing problems and leaks occur
Solution Approach 1:
The patent replaces fluidic control systems with multiple actuators with a single mechanical actuating system. A ball bearing mounted on the propeller hub converts the rotational movement of a single actuator into the pitch changes of multiple propeller blades, eliminating the need for multiple fluidic actuators and their associated sealing problems.
Solution Approach 2:
The ball bearing acts as an intermediary mechanism between the single actuator and the multiple propeller blades. It translates the linear or rotational movement of the actuator into coordinated pitch changes of all blades simultaneously, providing a reliable mechanical transmission path without fluid seals.
2Ease of operation
If multiple actuators are used to control each propeller blade, then precise pitch control is achieved, but the system becomes bulky and mass increases
Solution Approach 1:
The patent merges the function of multiple actuators into a single actuating mechanism. The ball bearing system allows one actuator to simultaneously control the pitch of multiple propeller blades, dramatically reducing the total mass and volume of the actuator system while maintaining precise control capability.
Solution Approach 2:
The single actuator coupled with the ball bearing mechanism performs the function of multiple actuators would otherwise be required. The ball bearing distributes the actuating force to multiple blades, making the single actuator universal for controlling all propeller pitch settings.
3Adaptability or versatility
If sliding elements are used in fluidic actuators to change blade pitch, then pitch adjustment is possible, but deformation of elements causes sealing leaks
Solution Approach 1:
The patent eliminates fluidic sliding elements by replacing them with a pure mechanical ball bearing system. The ball bearing provides a rigid, deformation-free mechanical connection that translates actuator movement into blade pitch changes without any fluid seals or flexible elements that could leak.
4Stability of the object's composition
If inertia is added to sliding elements to prevent ovalization during rotation, then structural stability is improved, but overall mass increases
Solution Approach 1:
The patent replaces the heavy inertia-based sliding elements with a lightweight ball bearing mechanism. The ball bearing inherently maintains structural stability during rotation through its spherical geometry and contact point mechanics, eliminating the need for added inertia while keeping the system lightweight.
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 system enhances operational reliability, reduces the risk of leaks, and optimizes compactness by using a single actuator to control both propellers, addressing the drawbacks of previous solutions.
Implementation Method 1
comprising an intermediate ball bearing mounted on the first propeller and configured so as to transmit the movement in translation of the rod of the actuator and breaks the connection in rotation with the first propeller
Data Source
AI summary
A system, including: a linear actuator axially arranged in a first propeller and rotatably secured thereto, a first linking mechanism connecting a rod of the linear actuator to a second propeller to change a setting of blades thereof, and including an intermediate bearing between the propellers, which is capable of transmitting translation of the rod of the linear actuator and disconnecting a rotatable link to the first propeller to make it possible to change the setting of the blades of the second propeller rotated in an opposite direction to the first propeller, and a second linking mechanism combined with blades of the first propeller to change a setting thereof.