Valve Spool Groove Geometry for Low-Force Quick Switching

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Solution Overview

Problem

Existing quick-acting valves require significant force to open due to opposing hydrodynamic axial forces, which hinder efficient movement and energy consumption.

Innovation Solution

The design features a valve slide with axially spaced grooves, including inlet-side and outlet-side cone sections with specific angles of inclination, supporting the opening movement by generating axial forces that assist in overcoming the return spring's force, and a central cone section with minimal inclination to facilitate quick opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional groove designs with symmetric conical sections are used, then the valve structure is simple and manufacturing is easy, but significant axial force is required to open the valve due to opposing hydrodynamic forces

Engineering Contradiction:
Improveaxial force required for openingVSAvoidgroove geometry complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by designing the first groove with a drain-side conical section having an inclination angle of less than 40 degrees (preferably 25-35 degrees), which is significantly less than the conventional symmetric design. This asymmetric groove geometry creates favorable hydrodynamic conditions that generate axial force in the opening direction, reducing the force required to open the valve while maintaining manufacturing feasibility.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies local quality by creating different conical sections with specific inclination angles at different locations within the groove. The drain-side conical section has a specific angle (less than 40 degrees) optimized for generating opening force, while the inlet-side conical section has a different angle (less than 90 degrees) optimized for generating additional opening force. This localized optimization of groove geometry addresses the force requirement without requiring complete redesign of the entire valve structure.

Inventive Principle:
Principle #3Local quality

2Productivity

If the valve spool is moved quickly to enable rapid switching, then productivity is improved, but the energy consumption increases due to the force required to overcome hydrodynamic resistance

Engineering Contradiction:
Improveswitching speedVSAvoidenergy required for spool movement
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent converts the harmful hydrodynamic resistance into a beneficial force by designing the asymmetric groove geometry that generates axial force in the opening direction. The flow through the specially angled conical sections creates pressure distribution that produces a force assisting the opening movement, thereby converting the energy that would normally be lost to hydrodynamic resistance into useful work that aids rapid switching while reducing overall energy consumption.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Force

If symmetric conical sections with standard inclination angles are used, then manufacturing precision requirements are moderate, but the axial force in closing direction is too high, hindering efficient opening movement

Engineering Contradiction:
Improveaxial force in closing directionVSAvoidcone section angle precision
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by modifying the inclination angle parameter of the drain-side conical section to be less than 40 degrees (preferably 25-35 degrees), which is a significant deviation from conventional symmetric designs. This parameter change fundamentally alters the hydrodynamic characteristics, reducing the axial force in the closing direction by creating favorable pressure distribution that generates opening force, while the specified angle range provides clear manufacturing guidelines that balance precision requirements with performance benefits.

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 design reduces the axial force required for closing and enhances the opening movement, allowing for rapid and efficient operation of the quick-acting valve, especially in normally-open configurations, while minimizing energy consumption.

Implementation Method 1

When flow passes through the first groove in the closing direction, an axial force in the opening direction is generated via this inlet-side conical section. The angle of inclination of the outlet-side cone section results in a reduced axial force in the closing direction when flowing through the first groove.

Methodology Applied
Scientific EffectHydrodynamic force: Pressure Gradient

Data Source

PatentEP3686465B1Quick switch valve
Publication Date: 2023.07.26 ROBERT BOSCH GMBH
  • EP3686465B1 patent drawingFigure 1
  • EP3686465B1 patent drawingFigure 2~3
  • EP3686465B1 patent drawingFigure 4~4a

AI summary

Revealbart is a quick-switching valve with two grooves in the valve spool that allow flow simultaneously in different axial directions. The first groove is optimized to amplify an axial force opposite to the flow direction through the groove. The second groove is optimized for its volumetric flow rate even at small opening cross-sections.