Servo Valve Filter Assembly With Supported Thin Perforated Filter

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Solution Overview

Problem

Conventional filter assemblies for servo valves are difficult to manufacture due to the need for robust materials to withstand assembly forces, leading to increased costs and manufacturing complexities, and often result in conical perforations that affect filtering performance.

Innovation Solution

A filter assembly with cylindrical constant nozzles that form a single unit, providing support for a thinner perforated filter member, allowing for easier assembly and manufacturing using lighter materials, and maintaining effective filtering performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a robust and thick filter member is used to withstand assembly forces during press-fit installation, then the filter member can be securely assembled, but it becomes more difficult to form perforations through the material, increasing manufacturing cost and time

Engineering Contradiction:
Improvefilter member robustnessVSAvoidperforation formation difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The filter assembly is segmented into multiple components: a support structure (constant nozzles) and a separate filter member. The support structure provides the necessary mechanical strength to withstand assembly forces, while the filter member can be made thinner and easier to perforate. This segmentation allows each component to be optimized independently for its specific function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support structure (constant nozzles) is prepared in advance to provide structural support during the assembly process. By pre-forming the support structure with appropriate geometry and rigidity, the filter member can be installed without requiring excessive thickness, thus facilitating easier perforation formation while maintaining assembly integrity.

Inventive Principle:
Principle #10Preliminary action

2Force

If a thick filter member is used to limit assembly force, then the filter member can be securely held, but the interference fit must be limited, requiring very tight manufacturing tolerances that increase manufacture time and cost

Engineering Contradiction:
Improveassembly forceVSAvoidtolerance requirement
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

By dividing the filter assembly into a support structure and a filter member, the mechanical load during assembly is distributed. The support structure absorbs the assembly forces through its rigid geometry, allowing the filter member to be thinner with looser tolerances while still achieving secure assembly through the combined structure.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If conventional press-fit assembly is used for the filter member, then the filter can be installed between opposing nozzles, but the filter member must be robust and thick, leading to increased manufacturing complexity and cost

Engineering Contradiction:
Improveassembly processVSAvoidfilter assembly structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The support structure and filter member are merged into a single integrated filter assembly unit. The support structure (constant nozzles) and filter member work together as a unified component that can be installed as one assembly, simplifying the installation process while allowing the filter member to be thinner and less complex than if it had to stand alone.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enables efficient and reliable assembly of a filter assembly using lighter, thinner materials, reducing manufacturing costs and complexities while maintaining effective fluid filtration in servo valves.

Implementation Method 1

servo valves are typically provided with particulate filters to filter contaminants in the fluid passing through the servo valve

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

The nozzles cooperating with the flapper are connected to the valve pressure supply port via constant nozzles

Methodology Applied
Scientific EffectPressure-driven flow: Pressure Gradient

Data Source

PatentEP4141263B1Servovalve comprising a filter assembly
Publication Date: 2024.09.25 HAMILTON SUNDSTRAND CORP
  • EP4141263B1 patent drawingFigure 1~2
  • EP4141263B1 patent drawingFigure 3~5
  • EP4141263B1 patent drawingFigure 6~8

AI summary

A filter assembly for a servo valve comprising: a first fluid nozzle (70') defining a first fluid passage therethrough between a first fluid inlet and a first fluid outlet; a second fluid nozzle (80') defining a second fluid passage therethrough between a second fluid inlet and a second fluid outlet; the first and second fluid nozzles arranged in end to end abutment with each other to form a tubular fluid nozzle unit in which the first and second fluid inlets are adjacent each other, and the first and second fluid passages align to form a common fluid passage through the tubular fluid nozzle unit, the first fluid outlet being at a first end of the tubular fluid nozzle unit and the second fluid passage being at a second, end of the tubular fluid nozzle unit; a recess (320) formed around an outer surface of the tubular fluid nozzle unit in a region where the first and second fluid inlets are located; and a perforated filter member (500) provided in the recess around the tubular fluid nozzle unit and across the first and second fluid inlets.