Landing Gear Pin Assembly With Dual-Chamber Grease Recirculation
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Solution Overview
Problem
Current methods for lubricating aircraft landing gear pin joints are inefficient, prone to blockages, and require frequent manual intervention, leading to increased maintenance costs and reduced joint performance over time.
Innovation Solution
A pin assembly with a reservoir and piston that allows bi-directional flow paths for lubricant recirculation, reducing the likelihood of blockages and extending maintenance intervals, and incorporating a self-reversing thread for mechanical simplicity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual greasing is used with grease spools and nipples, then lubrication can be applied to pin joints, but it is difficult to ensure adequate grease delivery and requires frequent manual intervention
Solution Approach 1:
The pin assembly automatically lubricates itself through the reciprocal movement of the piston driven by landing gear extension and retraction. The piston forces grease from the reservoir through bi-directional flow paths to the contacting surfaces without requiring manual intervention, making the system self-servicing.
Solution Approach 2:
The grease reservoir is pre-filled with lubricant before installation, and the piston is pre-positioned to initiate automatic lubrication upon landing gear operation. This preliminary preparation eliminates the need for frequent manual greasing during operation.
2Ease of operation
If grease channels are used to distribute lubricant, then grease can reach various points on the pin surface, but blockages in channels prevent grease delivery and give false impression of adequate supply
Solution Approach 1:
The reservoir is divided into two separate chambers by the piston, with each chamber having its own bi-directional flow path to the exterior. This segmentation ensures that blockage in one path does not prevent lubrication from the other chamber, improving reliability.
Solution Approach 2:
The flow paths are designed to be bi-directional, allowing grease to flow in either direction depending on piston position. This dynamic flow capability ensures continuous lubrication delivery even when one direction is partially blocked, as grease can alternate flow directions.
3Reliability
If multiple grease nipples are provided on landing gear, then comprehensive lubrication coverage is achieved, but operatives may overlook nipples and manual greasing is time consuming
Solution Approach 1:
The pin assembly performs its own lubrication function automatically through piston movement during normal landing gear operation. This eliminates the need for manual greasing operations entirely, improving productivity by removing the time-consuming manual process while maintaining reliable lubrication coverage.
4Reliability
If a piston divides the reservoir into two chambers with bi-directional flow paths, then lubricant recirculation reduces blockages and extends maintenance intervals, but device complexity increases
Solution Approach 1:
The piston serves multiple functions: it divides the reservoir into two chambers, provides reciprocating motion to drive bi-directional grease flow, and acts as a mechanical accumulator. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving blockage resistance through lubricant recirculation.
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 bi-directional flow paths ensure consistent lubricant distribution and reduce the need for frequent refilling, improving the reliability and longevity of joint lubrication while minimizing mechanical complexity and weight.
Implementation Method 1
a piston mounted for reciprocal movement within the reservoir... forcing grease out of apertures formed in the chamber walls
Data Source
AI summary
A pin assembly for insertion into a pin joint of an aircraft landing gear is disclosed. The pin assembly includes a reservoir for storing a lubricating agent and a piston mounted for reciprocal movement within the reservoir, the piston dividing the reservoir into a first chamber and a second chamber. A bi-directional flow path between the first and second chambers via the surface to be lubricated is provided by means of a first bi-directional flow path between the first chamber and the exterior of the pin assembly and a second bi-directional flow path between the second chamber and the exterior of the pin assembly. A pin assembly including an indicator system, and a pin insert in the form of a replaceable cartridge is also disclosed along with associated methods.