Hydraulic Valve Control Spool Feedback for Vibration Damping

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Solution Overview

Problem

Existing control devices for hydraulic consumers, such as slewing gears, exhibit PT-2 behavior, leading to vibrations that are difficult to regulate and can cause damage due to oscillations in the volume flow of hydraulic fluid, which are not effectively damped by current solutions.

Innovation Solution

A control device with a DC motor that recognizes and counteracts load-pressure-dependent forces on the control slide, using a brushless direct current motor with sensorless commutation and a rotation angle sensor to directly evaluate and compensate for vibrations, eliminating the need for additional pressure sensors and reducing wear and maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a pressure compensator is used in the control device, then the hydraulic system can maintain stable pressure, but PT-2 behavior is generated causing vibrations and oscillations in the volume flow

Engineering Contradiction:
Improvepressure stabilityVSAvoidvolume flow stability
Core Design Contradiction:
Stress or pressureVSStability of the object's composition

Solution Approach 1:

The control device incorporates a feedback mechanism where the load pressure acts directly on the control slide and is evaluated by the motor controller. The DC motor responds to pressure changes by adjusting the control slide position in real-time, creating a closed-loop feedback system that actively compensates for vibrations and oscillations, thereby resolving the contradiction between pressure stability and volume flow stability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control slide is designed to directly sense load pressure and transmit this information to the DC motor without requiring external pressure sensors. The system uses its own operational parameters (load pressure) to automatically regulate and dampen vibrations, making the system self-regulating and eliminating the PT-2 behavior that causes instability.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If multiple pressure sensors are installed to detect load pressure, then vibration detection precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveload pressure detection precisionVSAvoidnumber of pressure sensors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control slide itself serves as the pressure sensing element by directly experiencing the load pressure during operation. This eliminates the need for separate pressure sensors, as the control slide's position and the DC motor's response to pressure changes provide sufficient measurement information for vibration detection and compensation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control slide performs multiple functions: it regulates hydraulic flow, senses load pressure, and provides feedback for vibration compensation. By making the control slide multi-functional, the system achieves precise load pressure detection without adding separate sensing components, thereby reducing device complexity while maintaining measurement precision.

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

3Device complexity

If traditional control devices are used, then the system structure is simple, but wear increases and service life decreases due to lack of vibration compensation

Engineering Contradiction:
Improvecontrol device structureVSAvoidservice life
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The control device implements a feedback mechanism where the DC motor continuously monitors load pressure through the control slide and actively adjusts the control slide position to compensate for vibrations. This feedback-based vibration compensation reduces mechanical stress and wear on components, thereby extending service life and improving reliability without requiring overly complex structural modifications.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces traditional mechanical vibration damping mechanisms with an electro-hydraulic system using a DC motor and control electronics. This substitution allows for more precise and adaptive vibration compensation, reducing wear on mechanical components and extending the overall service life of the control device while maintaining reasonable structural complexity.

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

The solution effectively dampens and compensates for vibrations, providing a low-wear, long-lasting, and cost-effective control device that improves the regulation of hydraulic consumers by directly addressing PT-2 behavior and reducing the risk of damage from torsional vibrations.

Implementation Method 1

a control device with a DC motor that recognizes and counteracts load-pressure-dependent forces on the control slide

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A twisting of the motor shaft, which is proportional to the displacement of the control slide, can thus be evaluated and forwarded to a motor controller

Methodology Applied
Scientific EffectHall effect: Hall Effect

Implementation Method 3

the load pressure exerts a force on the control slide, which is transmitted to the motor, which evaluates this force

Methodology Applied
Scientific EffectPressure force: Pressure Increase

Implementation Method 4

Counter-voltage allows, which can be evaluated by the engine control. Due to the sensorless commutation, the pressure forces on the control slide are effectively transmitted to the DC motor and can be easily evaluated there to determine the rotor position

Methodology Applied
Scientific EffectCounter-voltage: Electromagnetic Induction

Data Source

PatentEP3775576B1Control device
Publication Date: 2022.07.20 HYDAC SYST & SERVICES GMBH
  • EP3775576B1 patent drawingFigure 1
  • EP3775576B1 patent drawingFigure 2
  • EP3775576B1 patent drawingFigure 3

AI summary

The invention relates to a control device for a hydraulic consumer which is susceptible to vibrations, comprising a valve (24) having a control spool (40) which can be actuated by means of an actuation apparatus (46). The valve (24) has a pressure supply connection (P) to which a deadweight tester can be connected, which can be supplied with pressurised fluid by a pressure supply apparatus. The actuation device (46) has a motor (74). A load-dependent force can be generated at the control spool (40) by means of a control apparatus (66). According to the invention, this force at the control spool (40) acts on an electronic motor controller (208) of the DC motor (74), which detects a change in the force and acts to damp the vibrations of the consumer, counteracting this change in the force.