Hydraulic Solenoid Valve Standby Current for Faster Spool Response

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Solution Overview

Problem

The existing drive control devices for hydraulic machines experience significant delays in response due to friction in the spool of the control valve, affecting the responsiveness of the solenoid valve.

Innovation Solution

A work machine equipped with a hydraulic pump, solenoid valve device, operation member, operation position determining section, operation intention determining section, and current control section that supplies a standby current to the solenoid valve when the operation member is within the neutral range and an operation intention is detected, reducing static friction and improving responsiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a neutral position detection system is used to forbid signal transmission when the operating lever is at neutral position, then control valve reliability is improved by preventing error signals, but solenoid valve responsiveness deteriorates due to static friction delay

Engineering Contradiction:
Improvecontrol valve reliabilityVSAvoidsolenoid valve responsiveness
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent applies preliminary action by supplying a standby current to the solenoid valve before the operating lever actually moves from the neutral position. The operation intention determining section detects the operator's intent through state changes of the operation member, and the current control section provides a standby current that prevents static friction from delaying the spool's response when operation begins, thus improving responsiveness while maintaining reliability through the neutral position detection system

Inventive Principle:
Principle #10Preliminary action

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 enhances the responsiveness of the solenoid valve device by applying a standby current when the operation member is within the neutral range, reducing static friction and enabling faster starting of the hydraulic actuator, thus improving operational efficiency and responsiveness.

Implementation Method 1

a solenoid valve device that controls a flow of a pressure oil supplied from the hydraulic pump to the hydraulic actuator

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP3467211B1Work machine
Publication Date: 2023.05.10 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP3467211B1 patent drawingFigure 1
  • EP3467211B1 patent drawingFigure 2
  • EP3467211B1 patent drawingFigure 3A~3B

AI summary

A work machine includes an operation intention determining section that determines whether or not an operator has an intention of operating an operation member based on a state change of the operation member, a current supply section that supplies a current to a solenoid valve device based on an operation of the operation member, and a current control section that permits supply of a standby current from the current supply section to the solenoid valve device when it has been determined by an operation position determining section that the operation member is disposed within a preset neutral range and it has been determined by the operation intention determining section that there is an intention of operating the operation member, the standby current being lower than a current of the time when a hydraulic actuator starts driving.