Hydraulic Filter With Compliant Slit Ends

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Solution Overview

Problem

Thin-walled metallic filters used in hydraulic systems are prone to mechanical weakness and instability due to densely cut holes, leading to potential buckling or excessive axial forces, and challenges in secure clamping within the system due to variations in length and manufacturing tolerances.

Innovation Solution

A filter design featuring a hollow body with a central section of laser-cut holes and compliant sections at the ends, comprising circumferentially extending slits that provide axial compliance, allowing for adjustable length and reduced axial forces, while maintaining filtration efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If holes are densely cut into the thin wall to achieve required filtration level, then filtration precision is improved, but the wall becomes weakened and prone to mechanical loads and buckling

Engineering Contradiction:
Improvefiltration precisionVSAvoidwall strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The filter body is divided into three distinct sections: a central section with densely cut holes for filtration, and two end sections with circumferential grooves that act as reinforcement ribs. This segmentation allows the filtration function and structural strength function to be separated into different zones, resolving the contradiction between needing dense holes for precision filtration and needing wall integrity for mechanical strength.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the filter is clamped between two elements to fix it in place and prevent movement, then positional stability is improved, but excessive axial force is generated onto the filter due to length variations and tolerances

Engineering Contradiction:
Improvepositional stabilityVSAvoidaxial force
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The end sections of the filter body have their wall thickness modified by forming circumferential grooves, changing the local mechanical parameters of the filter. This creates zones with different compliance characteristics - the grooved sections can deform to absorb dimensional variations and tolerance accumulations, reducing the transmission of excessive axial forces to the filter while maintaining overall positional stability through the clamping mechanism.

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If the filter wall is made thin to reduce mechanical loads, then weight and mechanical load are reduced, but the filter becomes prone to buckling under axial loads

Engineering Contradiction:
Improvefilter weightVSAvoidbuckling resistance
Core Design Contradiction:
Weight of moving objectVSStability of the object's composition

Solution Approach 1:

The filter body is segmented into a central thin-walled section for low weight and high filtration surface area, and two end sections with circumferential grooves that create reinforcement ribs. These reinforced end sections provide buckling resistance and structural stability while the central section maintains thin walls for weight reduction, allowing the filter to achieve both low weight and high buckling resistance simultaneously.

Inventive Principle:
Principle #1Segmentation

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 compliant sections enable axial adjustment and reduced mechanical stress, preventing filter loosening or excessive loading, and ensure consistent filtration performance under varying conditions.

Implementation Method 1

a first compliant section formed in said body at said first and/or second end of said filter, said compliant section comprising a plurality of slits which extend through said body and in a circumferential direction around said filter

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3903901A1Filter with compliant section
Publication Date: 2021.11.03 HAMILTON SUNDSTRAND CORP
  • EP3903901A1 patent drawingFigure 1~2b
  • EP3903901A1 patent drawingFigure 3
  • EP3903901A1 patent drawingFigure 4~5

AI summary

A filter (100) is described herein having a hollow body extending longitudinally between a first end (112) and a second end (113) and comprising a plurality of holes (111) formed through said body, and a first compliant section (160) formed in said body, said compliant section (160) comprising a plurality of slits (161) which extend through said body and in a circumferential direction around said filter (100). A nozzle/filter assembly is also described as well as a method for making the same.