Servo-Valve Nozzle Taper Geometry for Faster Actuator Response

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Solution Overview

Problem

Existing servo-valves face challenges in achieving high response speed due to drag issues during the oscillation movement of the nozzle, which degrades the response performance of the servo-valve and the actuator coupled to it.

Innovation Solution

The design incorporates a nozzle with a tapered inner wall and a specific taper angle greater than twice the inclination angle of the flow paths, reducing drag by optimizing the flow force exerted on the nozzle, allowing for faster movement and improved response performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the nozzle oscillates to control fluid flow, then the servo-valve can regulate hydraulic oil flow to actuators, but drag force acts on the nozzle during oscillation which degrades response performance

Engineering Contradiction:
Improveresponse speed of servo-valveVSAvoiddrag force on nozzle
Core Design Contradiction:
SpeedVSForce

Solution Approach 1:

The patent applies parameter changes by optimizing the taper angle of the nozzle's inner wall. Specifically, the taper angle is designed to be greater than twice the inclination angle of the flow path, which changes the geometric parameters of the nozzle to minimize the horizontal component of centrifugal force acting on the nozzle during oscillation, thereby reducing drag and improving response speed.

Inventive Principle:
Principle #35Parameter changes

2Speed

If the taper angle of the nozzle is increased to reduce drag, then response speed improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improveresponse speed of nozzleVSAvoidtaper angle precision
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent specifies a quantitative relationship for the taper angle (greater than twice the flow path inclination angle) which provides a clear design criterion. This parameter optimization balances the need for high response speed with manufacturability, as the specific angular relationship can be achieved through standard manufacturing processes while delivering the desired performance improvement.

Inventive Principle:
Principle #35Parameter changes

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 configuration enhances the response speed and accuracy of the servo-valve by minimizing the horizontal component of the centrifugal force, enabling quicker displacement of the nozzle and improving the overall performance of the actuator.

Implementation Method 1

a component of a flow force exerted from the hydraulic fluid to the tapered inner wall in a horizontal direction opposing to the movement direction of the nozzle

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3263915B1Servo-valve and fluidic device
Publication Date: 2024.11.20 NABTESCO CORP
  • EP3263915B1 patent drawingFigure 1
  • EP3263915B1 patent drawingFigure 2
  • EP3263915B1 patent drawingFigure 3A~3B

AI summary

The disclosure discloses a servo-valve (100) that drives an actuator by using a fluid. The servo-valve (100) includes a nozzle (200) that includes a discharge edge (222) forming an outline of a discharge port (221) from which the fluid is discharged and a tapered inner wall (240) growing narrower toward the discharge edge (222) and a receiver (300) that is provided with a flow path into which the fluid discharged from the discharge port (221) flows. The nozzle (200) is displaced in a direction different from the fluid discharge direction. The flow path (313, 314) extension direction is inclined with respect to a direction orthogonal to an inflow surface facing the nozzle (200) by an angle α. A taper angle determined by the tapered inner wall (240) is larger than twice the angle α. With such a configuration, a component of a flow force exerted from the fluid to the tapered inner wall (240) decreases. Since the nozzle (200) can be quickly displaced, a response speed of the actuator is improved.