Inlet Module Spool Position Detection via Pressure Correlation

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Solution Overview

Problem

Existing hydraulic control systems require additional position transducer elements to monitor the spool position in the inlet module, which complicates the construction and increases the number of components needed for safety functions.

Innovation Solution

The use of two pressure transducers, one in the pressure gallery and one in the tank gallery, allows for the determination of the spool's position by correlating pressure readings, eliminating the need for mechanical or optical sensors and enabling the monitoring of multiple spool positions without determining the exact position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a position transducer is used to monitor spool position, then safety monitoring is achieved, but device complexity increases due to additional elements

Engineering Contradiction:
Improvesafety monitoringVSAvoidconstruction complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the position sensing function from a dedicated position transducer and relocates it to existing pressure transducers. By measuring pressure differences in the pressure gallery instead of directly measuring spool position, the system achieves safety monitoring without adding position-specific sensing elements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The pressure transducers serve dual functions: monitoring both pressure conditions and inferring spool position. This multi-functionality eliminates the need for separate position sensing equipment, reducing overall device complexity while maintaining safety monitoring capabilities.

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

2Measurement precision

If mechanical or optical position sensors are used, then spool position detection is reliable, but the number of components increases

Engineering Contradiction:
Improvespool position detectionVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent merges the position detection function with the existing pressure monitoring system. By combining pressure sensing and position inference into a single integrated approach using pressure transducers, the system reduces component quantity while maintaining detection reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Pressure differences in the pressure gallery serve as an intermediary parameter that indirectly indicates spool position. This intermediary measurement approach allows reliable position detection without requiring direct mechanical or optical contact with the spool, reducing component count.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution simplifies the construction of the inlet module by reducing the number of required sensors and components, allowing reliable monitoring of the spool's position with only two pressure transducers, effectively addressing the complexity and component count issues in existing systems.

Implementation Method 1

a first pressure transducer reading the pressure in the pressure gallery, i.e., the common pressure line of the valve group, and a second pressure transducer permanently reading the pressure in another cavity

Methodology Applied
Scientific EffectPressure measurement:

Data Source

PatentEP3020983B1Inlet module for a valve group
Publication Date: 2020.04.22 DANFOSS POWER SOLUTIONS APS
  • EP3020983B1 patent drawingFigure 1
  • EP3020983B1 patent drawingFigure 2~3
  • EP3020983B1 patent drawingFigure 4~5

AI summary

A valve group (1) is disclosed comprising an inlet module (5) and at least one service module (2-4) connected to said inlet module (5), said inlet module(5) having a housing (19), a pressure port (PP), a pressure gallery (PG), a tank port (TP), a tank gallery (TG), a spool (20) movable in said housing (19) to interrupt in a first position (A) a connection between said pressure port (PP) and said pressure gallery (PG) and to connect in a second position (B) said pressure port (PP) and said pressure gallery (PG). The inlet module should have a simple construction. To this end said spool (20) in said first position (A) connects said pressure gallery (PG) and said tank gallery (TG), wherein a first pressure transducer (16) is provided to detect a first pressure in said pressure gallery (PG) and a second pressure transducer (17) is provided to detect a second pressure in said tank gallery (TG), said first pressure transducer (16) and said second pressure transducer (17) being connected to control means (18) determining the position of said spool (20) to be said first position (A) when said first transducer (16) and said second transducer (17) read a same pressure below a predetermined first threshold pressure and to be said second position (B) when said first pressure transducer (16) reads a higher pressure than said second pressure transducer (17).