Aircraft Shock Strut Shrinking Mechanism for Reduced Storage Length
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Solution Overview
Problem
Existing aircraft landing gear systems face challenges in reducing storage space when stowed, particularly in minimizing the length of the shock strut, which occupies significant space within the aircraft.
Innovation Solution
A system that includes a collar, torque arms, upper and lower bearings, and cams to facilitate the folding and rotation of the piston within the cylinder, allowing the landing gear to shrink by translating the wheel assembly and piston towards the aircraft attachment, thereby reducing the shock strut length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the landing gear is designed with a conventional shock strut structure, then the structural strength and reliability are maintained, but the storage space occupied by the landing gear is excessive due to the long shock strut length
Solution Approach 1:
The piston is nested within the cylinder through a shrinking mechanism. During retraction, the piston moves inward into the cylinder body, reducing the overall length of the shock strut. This nested configuration allows the landing gear to occupy less storage space while maintaining the functional length during deployment
Solution Approach 2:
The shock strut incorporates a dynamic shrinking mechanism that changes the effective length of the strut based on operational state. The mechanism includes movable components such as the piston and associated linkages that adjust the strut length dynamically - extended during landing operations and shortened during storage, resolving the contradiction between operational functionality and storage compactness
2Volume of stationary object
If the shock strut length is reduced to minimize storage space, then the storage volume is improved, but the structural strength and stability may be compromised
Solution Approach 1:
The nested piston-within-cylinder configuration maintains structural integrity by keeping the piston securely positioned within the cylinder during both extended and retracted states. The nesting design ensures that load-bearing components remain properly aligned and supported, preserving structural strength while enabling compact storage
Solution Approach 2:
The dynamic shrinking mechanism is designed to maintain structural strength throughout the transformation. The linkage system and bearing arrangements ensure that loads are properly transmitted even when the strut is in the shrunk configuration, preventing strength compromise during storage while enabling volume reduction
3Volume of stationary object
If a shrinking mechanism is added to reduce shock strut length, then the storage space is reduced, but the device complexity increases
Solution Approach 1:
The shrinking mechanism is merged with the existing shock strut structure rather than being added as a separate system. Components such as the piston, bearings, and linkages are integrated into the cylinder assembly, combining the shrinking function with the load-bearing and damping functions already present in the shock strut, thereby limiting the increase in overall system complexity
Solution Approach 2:
The mechanism components serve multiple functions simultaneously - the piston provides both the shrinking action and the damping function, the bearings support both the shrinking motion and the load-bearing requirements, and the linkages enable both length adjustment and structural stability. This multi-functionality reduces the need for additional dedicated components, limiting complexity increase while achieving the storage space reduction goal
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A system (200) for shrinking landing gear (130) includes a shock strut (202) having a cylinder (204) and a piston (206) to be received by the cylinder. The system further includes an upper cam (304) fastened to the piston and a lower cam (206) fastened to the cylinder. The system further includes a brace (208) configured to be coupled to the shock strut to lock the landing gear in a deployed position, and to fold towards the shock strut during retraction of the landing gear. The system further includes a collar (210) coupled to the brace and the piston and configured to rotate relative to the cylinder in response to folding of the brace such that rotation of the collar rotates the piston and the upper cam relative to the lower cam, the rotation of the upper cam relative to the lower cam forcing the piston towards the aircraft attachment within the cylinder.