Aircraft Shock Strut Telescoping Mechanism for Compact Stowage
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Solution Overview
Problem
Current aircraft landing gear systems face challenges in reducing the storage space required when the landing gear is stowed, particularly in shortening the length of the shock strut, which is a significant component of the landing gear.
Innovation Solution
A system comprising a shock strut with a cylinder, piston, collar, and torque arm, where a shrink linkage is used to rotate the collar and torque arm, transmitting a tensile force to compress the piston into the cylinder, effectively shortening the shock strut during retraction, and a brace linkage locks the gear in place during deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shock strut is designed to be long for effective shock absorption, then the shock absorption performance is improved, but the storage space required increases
Solution Approach 1:
The shock strut employs a telescoping mechanism where the piston is received by the cylinder, allowing the piston to nest within the cylinder during retraction. This nested configuration enables the shock strut to achieve a compact stored length while maintaining its full extended length for shock absorption operations.
2Volume of moving object
If the shock strut length is reduced during retraction, then the storage space is improved, but the structural complexity increases
Solution Approach 1:
The shock strut incorporates a dynamic retraction mechanism that allows the piston and cylinder assembly to move from an extended configuration during shock absorption to a retracted configuration for storage. The piston can telescope into the cylinder, and the entire assembly can be rotated into a compact position, providing adaptability between operational and storage states.
Solution Approach 2:
The shock strut is divided into separable components including the piston, cylinder, collar, and torque arm. These segmented elements can move independently during retraction, with the piston separating from the cylinder body and the collar rotating to facilitate compact storage while maintaining structural integrity during operation.
3Length of moving object
If a mechanism is added to force the piston to telescope into the cylinder, then the shock strut shrinking is improved, but the device complexity increases
Solution Approach 1:
The shock strut retraction mechanism is designed to be self-actuating, utilizing the kinetic energy and mechanical forces generated during normal shock absorption operations to drive the piston into the cylinder and rotate the collar into the compact position. The torque arm and shrink linkage work together to convert operational forces into retraction motion without requiring external actuation systems.
Solution Approach 2:
A shrink linkage is introduced as an intermediary mechanical element that connects the torque arm to the cylinder. This linkage serves as a mediator that converts the rotational motion of the collar and torque arm into the telescoping motion of the piston, facilitating the shrinking function while maintaining mechanical simplicity through pure mechanical advantage.
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 solution significantly reduces the overall length of the landing gear when stowed, thereby increasing storage space within the aircraft, allowing for more fuel, equipment, or features, by telescoping the piston into the cylinder, which can shorten the shock strut by 1 to 10 inches during retraction.
Implementation Method 1
a tensile force is transmitted through the shrink linkage between the torque arms and the cylinder, causing the piston to compress into the cylinder
Implementation Method 2
the shrink linkage is configured to force the piston into the cylinder in response to the collar rotating with respect to the cylinder
Implementation Method 3
a brace linkage coupled to the shock strut in order to lock the landing gear in a deployed position
Implementation Method 4
the torque arm is configured to resist rotation between the collar and the piston
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A system for shrinking landing gear includes a shock strut (202) having a cylinder (204) and a piston (206) to be received by the cylinder (204). The system further includes a collar (210) coupled to a brace linkage (208) and the piston (206), a torque arm (212) configured to resist rotation between the collar (210) and the piston (206), and a shrink linkage (240) coupled between the torque arm (212) and the cylinder (204). The collar (210) rotates relative to the cylinder (204) in response to retraction of the landing gear. Rotation of the collar (210) rotates the piston (206) and the torque arm (212) relative to the cylinder (204). The rotation of the collar (210) relative to the cylinder (204) forces, via the shrink linkage (240), the piston (206) towards the aircraft attachment within the cylinder (204).