Rotary Spool Servo Valve for High-Flow Reliable Control

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Solution Overview

Problem

Conventional servo valve systems are bulky, complex, and prone to failure due to large size and multiple moving parts, which complicates manufacturing, assembly, and reduces responsiveness and reliability, especially when handling high fluid flows and high operation frequencies.

Innovation Solution

A servo valve assembly with a simplified design featuring a spool assembly and drive assembly using permanent magnets and coils to rotate the spool, reducing the number of complex parts and improving manufacturing ease, while maintaining compactness and responsiveness, by aligning spool openings with fluid channels to control fluid flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional servo valve systems use large valve orifices and multiple moving parts to handle high fluid flows, then the fluid flow capacity is improved, but the device size increases and reliability decreases

Engineering Contradiction:
Improvefluid flow capacityVSAvoidsystem reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent extracts and eliminates unnecessary moving parts from the conventional servo valve system. Specifically, it removes the flapper, nozzle, and feedback spring mechanisms, retaining only the essential spool valve component. This extraction reduces the number of potential failure points while maintaining the core fluid flow control function, thereby improving reliability without sacrificing flow capacity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the servo valve into distinct functional zones within a single spool component: a metering zone for flow control and a feedback zone for position sensing. This segmentation allows each zone to be optimized independently for its specific function while being integrated into a unified structure, improving both reliability and flow handling capability.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If conventional servo valve systems use multiple moving parts and complex construction, then the fluid flow control capability is improved, but the device complexity increases and manufacturing difficulty increases

Engineering Contradiction:
Improvefluid flow control capabilityVSAvoidconstruction complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the metering function and feedback function into a single integrated spool valve structure. The spool contains both the metering openings for flow control and the feedback openings for position sensing, eliminating the need for separate flapper, nozzle, and feedback spring assemblies. This merging maintains full fluid flow control capability while dramatically reducing construction complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spool valve component performs multiple functions simultaneously: it meters fluid flow through its metering openings, provides position feedback through its feedback openings, and acts as the sole moving part for control. This multi-functionality eliminates the need for separate dedicated components for each function, reducing overall device complexity while maintaining adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If conventional servo valve systems use long fluid paths and multiple channels, then the fluid flow management is improved, but the response time increases

Engineering Contradiction:
Improvefluid flow management capabilityVSAvoidresponse time
Core Design Contradiction:
ProductivityVSSpeed

Solution Approach 1:

The patent extracts and eliminates the long fluid paths and multiple intermediate channels found in conventional systems. By removing the flapper-nozzle feedback mechanism and feedback springs, the fluid path is shortened to direct connections between the spool valve and actuator. This extraction maintains effective fluid flow management while significantly reducing response time.

Inventive Principle:
Principle #2Taking out (Extraction)

4Quantity of substance

If conventional servo valve systems use large component sizes to handle high flows, then the fluid flow capacity is improved, but the device volume increases

Engineering Contradiction:
Improvefluid flow capacityVSAvoiddevice volume
Core Design Contradiction:
Quantity of substanceVSVolume of moving object

Solution Approach 1:

The patent segments the fluid flow control into concentrated zones within the spool valve: small precision metering openings for flow control and small feedback openings for position sensing. This segmentation allows high fluid flow capacity to be achieved through optimized flow dynamics in compact zones rather than requiring large overall component dimensions, thereby reducing device volume.

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 solution enables efficient handling of large fluid flows at high frequencies with fewer expensive and complex parts, simplifying manufacturing and assembly, and enhancing the reliability and responsiveness of the servo valve system.

Implementation Method 1

a spool assembly and drive assembly which rotates the spool to align the spool openings with the fluid channels

Methodology Applied
Scientific EffectElectromagnetic interaction: Lorentz Force

Data Source

PatentEP3901473B1Servo-valve
Publication Date: 2024.10.09 HAMILTON SUNDSTRAND CORP
  • EP3901473B1 patent drawingFigure 1~2
  • EP3901473B1 patent drawingFigure 3~4
  • EP3901473B1 patent drawingFigure 5

AI summary

A servo valve comprising: a fluid transfer valve assembly comprising a supply port (61) and a control port (62); a valve spool (70) arranged to regulate flow of fluid from the supply port (13) to the control port in response to a control signal; and a drive means (50) configured to move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow; wherein the drive means is arranged to rotate the spool relative to the fluid transfer assembly, the spool provided with openings (71,72) arranged to selectively align with or block flow channels (67, 68) in the fluid transfer assembly according to the direction and degree of rotation of the spool.