Aircraft Landing Gear Shock Absorber Degassing Orifice
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing shock absorbers for aircraft landing gear take a long time to return to their nominal state with hydraulic fluid filling the chamber under the diaphragm, which can lead to incomplete filling before landing, posing a risk during aircraft landing.
Innovation Solution
Incorporating a degassing orifice offset in height relative to the rolling orifice allows preferential gas transfer through the degassing orifice and hydraulic fluid transfer through the rolling orifice, reducing the time required to return to the nominal state with the chamber filled solely with hydraulic fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic fluid and gas migrate through rolling orifices to return to initial state, then the shock absorber returns to nominal position, but the return time is quite long
Solution Approach 1:
The separation is segmented into two distinct functional zones: a rolling orifice region for hydraulic fluid transfer and a degassing orifice region for gas transfer. This segmentation allows each type of fluid to be handled through its dedicated pathway, with the degassing orifice positioned above the rolling orifice to preferentially capture rising gas bubbles, thereby accelerating the overall return process to nominal position
Solution Approach 2:
The degassing orifice acts as an intermediary element that facilitates the preferential escape of gas from the hydraulic fluid mixture. By positioning this orifice above the rolling orifice, gas bubbles can escape through the degassing path before interfering with hydraulic fluid flow through the rolling orifices, thus mediating the separation of gas and fluid transfer functions
2Quantity of substance
If gas partially fills the oil chamber under the diaphragm, then the chamber volume is occupied, but the chamber is not fully filled with hydraulic fluid
Solution Approach 1:
The degassing orifice is positioned and sized to enable preliminary gas removal from the oil chamber during the shock absorber's operation. This preliminary action of gas evacuation occurs as the shock absorber cycles, preventing gas accumulation that would otherwise delay hydraulic fluid filling and ensuring landing readiness is achieved more quickly
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 design significantly reduces the time to achieve the nominal state, potentially saving several minutes and ensuring the chamber under the diaphragm is fully filled with hydraulic fluid before landing.
Implementation Method 1
the pressure of the fluid at the level of the rolling orifice is greater than that which prevails in the fluid at the level of the degassing orifice, due to the difference in height
Implementation Method 2
The hydraulic fluid which stagnates above the separation and which must return under the separation by gravity
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a shock absorber for the landing gear of an aircraft, including two members (1, 2) mounted so as to be capable of telescopically sliding one in the other and defining an inner volume filled with a hydraulic fluid and a gas and divided into at least two chambers (7, 8) by a partition (5) including at least one throttling opening (10) through which the hydraulic fluid passes from chamber to chamber, in particular upon a compression of the shock absorber. According to the invention, the partition includes at least one degassing opening for allowing the gas to transfer from one chamber to the other when the landing gear is in the extended position, the degassing opening being vertically offset relative to the throttling opening so as to be located above the latter when the landing gear is in the extended position.