Serial-Parallel Hydraulic Valve Logic for Stable Multi-Section Flow

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Solution Overview

Problem

Existing hydraulic circuits for machines like front loaders and shovels face issues in series and parallel configurations, where simultaneous operation of multiple sections is hindered by end-of-stroke limitations and uneven flow distribution, respectively, leading to unstable movements.

Innovation Solution

A logic switching element is introduced into the hydraulic circuit, controlled by a sequence valve or pressure relief valve, allowing the circuit to switch between series and parallel operations based on operating conditions, ensuring stable and efficient distribution of hydraulic flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If hydraulic circuit is configured in series, then flow distribution is simplified, but simultaneous operation of multiple sections is limited when one cylinder reaches end of stroke

Engineering Contradiction:
Improveflow distributionVSAvoidsimultaneous operation capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The hydraulic circuit dynamically switches between series and parallel configurations based on operating conditions. A logic element responds to pressure signals from sequence valves to reconfigure the hydraulic connections, allowing the system to adapt its topology rather than being fixed in one configuration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The hydraulic circuit is designed to perform multiple functions through a single integrated system that can operate in both series and parallel modes. The logic element and sequence valves enable the same circuit to provide both simplified flow distribution and simultaneous operation capability as needed.

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

2Adaptability or versatility

If hydraulic circuit is configured in parallel, then simultaneous operation of multiple sections is enabled, but flow distribution becomes uneven depending on load pressures

Engineering Contradiction:
Improvesimultaneous operation capabilityVSAvoidflow distribution control
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system dynamically adjusts its configuration based on real-time pressure conditions. When parallel operation is detected via pressure signals, the logic element switches the circuit to parallel mode to enable simultaneous operation, while in other conditions it maintains series configuration for controlled flow distribution.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Pressure signals from sequence valves provide feedback about the operating state of each cylinder section. This feedback controls the logic element to automatically switch between series and parallel configurations, ensuring optimal flow distribution and simultaneous operation capability based on actual load conditions.

Inventive Principle:
Principle #23Feedback

3Device complexity

If fixed series or parallel configuration is used, then circuit design is simple, but operational stability and flexibility are compromised

Engineering Contradiction:
Improvecircuit designVSAvoidoperational stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Rather than using a fixed configuration, the circuit employs dynamic switching between series and parallel modes based on operational needs. This is achieved through pressure-actuated sequence valves and a logic element that automatically reconfigures the hydraulic connections without requiring complex external control systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The hydraulic circuit self-regulates its configuration based on internal pressure signals from the operating cylinders. The sequence valves detect when cylinders reach certain positions and automatically trigger the logic element to switch modes, eliminating the need for external sensors or complex control electronics while maintaining operational stability.

Inventive Principle:
Principle #25Self-service

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 enables a stable and efficient operation by calibrating the sequence valve or spool position, allowing the circuit to adapt and maintain simultaneous movements across multiple sections, enhancing the operational flexibility and reliability of hydraulic systems.

Implementation Method 1

the logic switching element is controlled by a sequence valve or by a pressure relief valve

Methodology Applied
Scientific EffectPressure detection: Pressure Gradient

Implementation Method 2

the logic switching element is controlled by a sequence valve or by a pressure relief valve

Methodology Applied
Scientific EffectPressure regulation: Pressure Gradient

Data Source

PatentEP3205889B1Serial-parallel hydraulic valve with logic switching element
Publication Date: 2024.10.30 WALVOIL
  • EP3205889B1 patent drawingFigure 1~2
  • EP3205889B1 patent drawingFigure 3~5
  • EP3205889B1 patent drawingFigure 3A~4A

AI summary

Hydraulic directional valve, with mixed series (S) and parallel (P) hydraulic circuit consisting of two or more sections and one logic switching element (E, E1, E2), characterized in that said logic element (E, E1, E2) in neutral position involves connecting the series channel (S) of said mixed series and parallel hydraulic circuit with the branch downstream of pressure (P1), and at the same time isolates the pressure channel (P) of the parallel circuit and the discharge (T); when switching the distributor, the latter reaches a second position, which involves closing the channel (S) and simultaneously opening the parallel channel (P) towards the branch downstream of pressure (P1), and in this case channel (S) is set to discharge by the connection with (T); a control channel (1) copies the signal from the pressure channel (P) bringing it on one side of the logic element (E, E1, E2).