Back-Drivable Gearbox Rotary Downlock Actuator
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Solution Overview
Problem
Electrically powered downlock actuators for landing gear systems face challenges in fitting within the same spatial constraints as hydraulically powered systems while maintaining efficiency and reliability, as they often lose efficiency in converting rotary motor output to linear motion.
Innovation Solution
An electrically powered downlock actuation system that uses the rotary output of a motor to directly drive a locking mechanism coupled to a landing gear brace, employing a back-drivable gearbox and link rod to achieve efficient locking and unlocking operations without linear motion, thus maintaining compactness and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrically powered downlock actuator converts rotary motor output to linear motion, then it can actuate the locking linkage system, but it loses efficiency and increases device complexity
Solution Approach 1:
The patent replaces the conventional linear actuator mechanism with a rotary actuation system. The motor's rotary output directly drives the locking mechanism through a back-drivable gearbox, eliminating the need for rotary-to-linear conversion. This substitution maintains actuation capability while improving energy efficiency by avoiding unnecessary mechanical conversion steps.
Solution Approach 2:
The patent extracts and eliminates the linear motion conversion mechanism from the actuation system. By removing the intermediate conversion stage (screw mechanism, rack and pinion, or cylindrical cam), the system directly transmits rotary motion to the locking linkage, reducing mechanical complexity and energy loss.
2Volume of moving object
If an electrically powered downlock actuator is designed to fit within hydraulic system spatial constraints, then it maintains compactness, but it becomes difficult to avoid force inefficiencies
Solution Approach 1:
The patent replaces the space-consuming linear actuator with a compact rotary actuation system. The motor and gearbox occupy less volume than equivalent linear actuators, fitting within hydraulic system constraints while eliminating force inefficiencies associated with rotary-to-linear conversion.
Solution Approach 2:
Instead of converting rotary motion to linear motion as in conventional systems, the patent inverts the approach by using rotary motion directly to actuate the locking mechanism. This inversion eliminates the conversion step that causes force inefficiencies and reduces the required actuator volume.
3Reliability
If a conventional electrically powered downlock actuator uses linear motion mechanism, then it can lock and unlock the landing gear, but it increases device complexity and weight
Solution Approach 1:
The patent replaces complex linear motion mechanisms (screw actuators, rack and pinion, cylindrical cams) with a simple rotary actuation system. The motor's rotary output directly drives the locking mechanism through a back-drivable gearbox, significantly reducing the number of moving parts and mechanical complexity while maintaining reliable locking and unlocking functionality.
4Adaptability or versatility
If the downlock actuator components translate longitudinally during operation, then it responds to landing gear movement, but it increases the spatial envelope required
Solution Approach 1:
The patent replaces the longitudinal translation mechanism with a rotary actuation system. The motor and gearbox remain stationary while the locking mechanism rotates to achieve locking and unlocking, eliminating the need for component translation and reducing the spatial envelope required for actuator operation.
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 toggles the landing gear braces between locked and unlocked positions with precise control, maintaining the same spatial and weight constraints as hydraulic systems while minimizing force inefficiencies and ensuring reliable operation.
Implementation Method 1
The downlock actuator includes a back-drivable gearbox coupled to the motor and having a connecting output shaft that extends from the back-drivable gearbox in a direction substantially parallel to a longitudinal axis of the link rod
Implementation Method 2
A link rod is coupled to the connecting output shaft of the back-drivable gearbox. The link rod is mounted for longitudinal translation, substantially parallel to the longitudinal axis of the upper brace, and rotation, relative to the connecting output shaft
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A downlock actuator may comprise an electric motor, a gearbox coupled to the electric motor, the gearbox comprising a rotary output shaft, and a connecting output shaft having a first end and a second end, the first end being coupled to the rotary output shaft of the gearbox, wherein the connecting output shaft is configured to rotate between a shaft locked position and a shaft unlocked position, wherein the gearbox is back-drivable in response to the connecting output shaft being in the shaft unlocked position.