Flapper Servo Valve Assembly With Press-Fit Core and Integrated Nozzles

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Solution Overview

Problem

Conventional flapper type servo valves are complex, expensive, and time-intensive to manufacture, requiring precise air gaps and brazed connections, leading to a bulky envelope and high production costs.

Innovation Solution

The servo valve design incorporates a flapper assembly with a press-fit mechanism, eliminating the need for brazed connections and precise air gaps, and integrates nozzles directly into the valve body, allowing for sliding movement instead of rotational motion, and simplifies calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional flapper type servo valves use brazed connections and precise air gaps, then assembly precision and reliability are improved, but manufacturing complexity and production cost increase

Engineering Contradiction:
Improveassembly precisionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The flapper assembly is merged with the drive core by press-fitting the flapper directly into the drive core, eliminating separate brazed connections. The nozzle is merged with the valve body by integrating it as a single component, eliminating separate assembly steps and brazing operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The complex brazing process and precise air gap requirements are extracted/eliminated from the manufacturing process. The design takes out the need for specialized brazing operations and ultra-precise gap control by using press-fit connections instead.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If conventional flapper type servo valves use rotational motion with precise air gaps, then valve accuracy is improved, but manufacturing time and production cost increase

Engineering Contradiction:
Improvevalve accuracyVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

Instead of using rotational motion with precise air gaps, the invention inverts the approach by using sliding/linear motion where the flapper moves axially within the nozzle. This reverses the conventional mechanism while achieving the same flow control function with simpler manufacturing.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The design accepts slightly different wear characteristics of sliding components compared to rotational components, using simpler, more easily replaceable parts that reduce manufacturing complexity and time.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If conventional flapper type servo valves use separate nozzle components, then assembly flexibility is improved, but device envelope and production cost increase

Engineering Contradiction:
Improveassembly flexibilityVSAvoidvalve envelope
Core Design Contradiction:
Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The nozzle is merged with the valve body into a single integrated component. This eliminates the need for separate nozzle assembly and reduces the overall valve envelope volume while maintaining all necessary flow control functions.

Inventive Principle:
Principle #5Merging (Combining)

4Strength

If conventional flapper type servo valves use brazed connections, then joint strength is improved, but manufacturing complexity and production time increase

Engineering Contradiction:
Improvejoint strengthVSAvoidproduction time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The brazing process (thermal/chemical joining) is replaced with a mechanical press-fit connection. This substitution eliminates the need for brazing equipment, reduces production time, and simplifies the manufacturing process while maintaining sufficient joint strength for the application.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 reduces manufacturing complexity and cost, while maintaining accuracy and reliability, resulting in a smaller and lighter servo valve assembly.

Implementation Method 1

a magnetic coil, a core configured to move axially with respect to the coil when the coil is powered by a current dependent on the control signal

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnetic Induction

Implementation Method 2

obtain pressurised fluid from a high pressure source which is transmitted through the valve from which the fluid is output as a control fluid

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP4194705B1Flapper servo valve
Publication Date: 2026.04.22 HAMILTON SUNDSTRAND CORP
  • EP4194705B1 patent drawingFigure 1A~1B
  • EP4194705B1 patent drawingFigure 2A~2B
  • EP4194705B1 patent drawingFigure 3A~3D

AI summary

A servo valve comprising: a fluid transfer valve assembly comprising a valve body having a supply port (110) and a control port (C1); the valve body (201) comprising first and second nozzles (21A, 21B) and a drive member (500) therebetween, arranged to regulate flow of fluid from the supply port (110) to the control port in response to a control signal; and a drive assembly (1000) comprising a magnetic coil (700) and a core (600) passing through the coil (700) and configured to move axially with respect to the coil when the coil is powered by a current dependent on the control signal, the drive assembly arranged to move the drive member (500) relative to the first and second nozzles (22A, 22B) in response to the control signal, wherein the drive member comprises an elongate flapper member (500) having a first end (501) located between the first nozzle (22A) and the second nozzle (22B) and a second end (502) received in the core (600) of the drive assembly, such that axial movement of the core causes side-to-side movement of the end of the drive member between the nozzles (22A, 22B) such as to vary the spacing (A, B) between the end (501) and at least one of the nozzles as the end moves relative to the first and second nozzles.