Electric Actuator Key-Taper Locking Mechanism
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Solution Overview
Problem
Existing electric actuators for lifting aircraft legs face challenges when subjected to external forces or impacts at the extended position, requiring significant strength and braking performance, leading to large and heavy components.
Innovation Solution
The design incorporates a recess on the nut with a key that fits into a tapered portion on the cylinder body, distributing external forces to the cylinder body rather than the screw shaft, reducing the load on the screw shaft and allowing for a smaller and lighter actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric actuator uses a screw shaft and mechanical brake to hold the piston rod at the extended position, then the leg can be extended and locked, but the screw shaft and mechanical brake must withstand heavy external forces and impacts during takeoff and landing, resulting in large and heavy components
Solution Approach 1:
The locking function is segmented between two separate mechanisms: the screw shaft for fine position control and the key-tapered portion mechanism for heavy-load locking. This division allows each component to be optimized for its specific function, with the key-tapered portion handling external forces during takeoff and landing while the screw shaft maintains positioning accuracy.
Solution Approach 2:
The key acts as an intermediary element between the nut and the cylinder body, transferring the locking force from the nut's outward movement to the tapered portion on the cylinder body. This intermediary mechanism allows the screw shaft to avoid direct exposure to heavy external forces during takeoff and landing.
2Strength
If the screw shaft is made stronger to withstand external forces during takeoff and landing, then the actuator can handle heavy loads, but the actuator size and weight increase significantly
Solution Approach 1:
The load-bearing function is segmented: the key-tapered portion mechanism handles heavy external forces during takeoff and landing, while the screw shaft handles only the driving torque for position adjustment. This segmentation allows the screw shaft to be smaller and lighter while the overall system maintains high load-bearing capacity.
Solution Approach 2:
The outward movement of the nut, which could be considered a harmful displacement, is converted into a beneficial locking action. As the nut moves outward due to external forces, it pushes the key against the tapered portion, which in turn locks the piston rod in place, transforming the potentially damaging force into a secure locking mechanism.
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 configuration effectively reduces external forces acting on the screw shaft, resulting in a smaller and lighter electric actuator while maintaining effective locking and retraction mechanisms.
Implementation Method 1
a piston rod advances to move the key outward to cause the key to fit to the tapered portion, locking the piston rod by the key
Data Source
AI summary
An object of the present invention is to provide an electric actuator having a structure capable of reducing an external force or impact acting on a screw shaft when a piston rod is at a stretched position. An electric actuator includes a nut, a piston rod, recesses, keys, holes, and a tapered portion. Into the nut, a screw shaft is screwed. The piston rod moves linearly via the nut. The recesses are formed on an outer circumferential surface of the nut. The keys are each provided to a recess. The tapered portion is formed on an inner wall of the cylinder body. The piston rod advances to move the keys outward to cause the keys to fit to the tapered portion to block retraction of the piston rod.