Propeller Pitchlock System with Rotating Interface
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional variable pitch propeller systems face challenges in maintaining blade pitch during hydraulic supply failures, as existing pitchlock systems are complex and prone to malfunctions.
Innovation Solution
A simplified pitchlock system featuring a ballscrew screw with a pitchlock nut and ballnut, a pitchlock actuation rod with a ball bearing aperture, and a belleville spring that biases the ballscrew screw towards an axially fixed surface, allowing for a more reliable pitchlock mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pitchlock system with pitchlock ballscrew and pitchlock ballnut is used, then the propeller blades can be locked in position during hydraulic failure, but the system becomes complex and prone to malfunctions
Solution Approach 1:
The patent extracts the pitchlock ballscrew from the hub assembly and relocates it to the actuator, separating the pitchlock function from the traditional blade pitch change system. This extraction simplifies the overall system by eliminating the need for a separate pitchlock ballscrew and ballnut mechanism within the hub, reducing component count and potential failure points while maintaining the pitchlock function during hydraulic failure
Solution Approach 2:
The patent merges the pitchlock actuation rod with the actuator's existing rotational interface. The pitchlock actuation rod rotates within the actuator's ball bearing aperture, combining the pitchlock actuation mechanism with the actuator's rotational motion capability. This integration eliminates separate pitchlock actuators and reduces system complexity while maintaining reliable pitchlock functionality
2Ease of manufacture
If a simplified pitchlock system with pitchlock actuation rod is used, then the assembly process becomes easier, but the system must still maintain reliability during hydraulic supply failure
Solution Approach 1:
The belleville spring is pre-compressed and positioned within the actuator before final assembly, establishing the initial pitchlock position and ensuring the ballscrew is biased toward the locked position. This preliminary action ensures that upon hydraulic failure, the system automatically defaults to the safe locked state without requiring additional actuation, simplifying assembly while guaranteeing reliability
Solution Approach 2:
The pitchlock actuation rod serves as an intermediary element that translates the actuator's rotational motion into linear displacement of the ballscrew. By rotating within the actuator's ball bearing aperture, the actuation rod converts rotational movement into the linear motion needed to engage or disengage the pitchlock, simplifying the mechanism while maintaining reliable operation during hydraulic failure
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 effectively locks propeller blades in their last pitch position during hydraulic failures, ensuring stability and simplifying the assembly process with a more robust and easier-to-install design.
Implementation Method 1
a belleville spring which biases the ballscrew screw towards an axially fixed surface of the actuator in a pitchlock position
Implementation Method 2
a ball bearing aperture for receiving multiple ball bearings
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A pitchlock system (26) includes a ballscrew screw (46) mounted along an axis of rotation of an actuator. The ballscrew screw (46) has an internal ballscrew bore. A pitchlock nut (56) is mounted about the ballscrew screw (46), the pitchlock nut (56) including an internal pitchlock nut thread (57). A ballscrew ballnut (50) is mounted about the ballscrew screw (46) and axially adjacent the pitchlock nut (56). A pitchlock actuation rod (64) is mounted axially within the internal ballscrew bore, the pitchlock actuation rod (64) having an internal pitchlock actuation bore and a ball bearing aperture (132) for receiving multiple ball bearings (55). A pitchlock retainer pin (66) is mounted axially within the internal pitchlock actuation bore. A belleville spring (68) biases the ballscrew screw (46) towards an axially fixed surface of the actuator in a pitchlock position, the ballscrew screw (46) being movable between an operational position and the pitchlock position.