Aircraft Hydraulic Filter Insert Segmentation

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Solution Overview

Problem

The existing filtering devices for aircraft hydraulic circuits face challenges due to high tightening torque requirements, leading to cumbersome and heavy torque wrenches, stress on the hydraulic block threads, and risk of fatigue degradation, especially with materials like aluminum or titanium.

Innovation Solution

A filtering device design that incorporates an insert screwed into the hydraulic block, which is not intended for frequent disassembly, and a tank with a pin and belt mechanism to secure the filter cartridge, allowing for reduced torque requirements and preventing fatigue cycling of the threads, using stainless steel for the insert to enhance durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the tank is directly screwed onto the hydraulic block with high tightening torque, then mechanical strength and thread engagement are ensured, but the torque wrench becomes heavy and difficult to handle, and the thread suffers from fatigue degradation

Engineering Contradiction:
Improvemechanical strength of threadVSAvoidhandling of torque wrench
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The connection system is segmented into two parts: a permanent insert screwed into the hydraulic block and a removable tank screwed onto the insert. This segmentation allows the high tightening torque to be applied only once to the insert during installation, while the tank can be removed and reinstalled without subjecting the hydraulic block thread to repeated high-stress cycles.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insert acts as an intermediary element between the hydraulic block and the tank. It absorbs the high tightening torque during initial installation and serves as a durable interface for repeated tank connections, protecting the hydraulic block thread from fatigue degradation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If high tightening torque is applied to ensure mechanical strength, then thread engagement is secure, but the hydraulic block thread deteriorates quickly due to fatigue cycling from frequent screwing and unscrewing

Engineering Contradiction:
Improvethread engagement strengthVSAvoidthread durability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The connection system is divided into a permanent insert and a removable tank. The insert receives the high tightening torque once during installation and remains fixed, while the tank is screwed onto the insert's external thread for removal and reinstallation, isolating the hydraulic block thread from fatigue cycling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insert is pre-installed and tightly secured into the hydraulic block before the tank is attached. This preliminary action ensures that the high-strength thread engagement is established once, and subsequent tank operations do not subject the hydraulic block thread to repeated stress cycles.

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If the tank is made large to accommodate the filter cartridge, then filtering capacity increases, but the tightening torque increases proportionally, making the torque wrench heavier and more difficult to handle

Engineering Contradiction:
Improvefiltering capacityVSAvoidtorque wrench handling
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The system is segmented into a permanently installed insert and a removable tank. This allows the tank to be designed for optimal filtering capacity without being constrained by the need for frequent high-torque installations, as the insert remains fixed and the tank can be easily attached and detached.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insert serves as an intermediary that provides a robust mounting base for the tank. It absorbs the high tightening torque during initial installation, enabling the tank to be made larger for increased filtering capacity without proportionally increasing the difficulty of handling the torque wrench during routine operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2100653B1Filter device for aircraft with an element for polarising and inserting the cartridge
Publication Date: 2011.08.31 SAFRAN LANDING SYSTEMS
  • EP2100653B1 patent drawingFigure 1~2
  • EP2100653B1 patent drawingFigure 3
  • EP2100653B1 patent drawingFigure 4

AI summary

The device has a hydraulic block (1) made of titanium and receiving a removable filter (2), where the filter comprises a tank (3) for receiving a filtering cartridge (4). An insert (21) is screwed in an internal thread (20) of the block by tightening. The insert has an internal thread (22), in which the tank is screwed. A rotation stopping unit is formed of a shoulder (23) and a toothed tab (32) for stopping rotation of the tank, once the tank is screwed in the insert. The insert is made of stainless steel.