Hydraulic Valve Pressure Routing for Constant Multi-Function Operability

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Solution Overview

Problem

Fluid control devices with multiple fluid control valves in a closed center circuit type require complex configurations and increased parts to manage pressure using both main and secondary relief valves, leading to increased size and assembly complexity.

Innovation Solution

A fluid control device configuration with a main relief valve for the function with maximum load pressure and a secondary relief valve for other functions, utilizing a passage switching unit to direct hydraulic fluid pressure through check valves and passages, allowing for simplified management of hydraulic fluid pressure without complicating the device configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple relief valves are provided for different pressure requirements, then pressure control precision is improved, but device complexity increases

Engineering Contradiction:
Improvepressure control precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The load sensing passage serves multiple functions: it guides port pressure to the relief valve for pressure control, and simultaneously guides load pressure to the pressure compensation valve for flow rate control. This multi-functional design eliminates the need for separate passages, reducing device complexity while maintaining precise pressure control through the main and secondary relief valves.

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

Solution Approach 2:

The patent combines the relief valve circuit and pressure compensation valve circuit by using a common load sensing passage. The port pressure and load pressure are guided through the same passage to their respective components, merging the functions of pressure control and flow rate control into a unified system, thereby reducing the number of separate components and assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If pressure compensation valves are provided for each fluid control valve, then operability is improved, but device complexity increases

Engineering Contradiction:
ImproveoperabilityVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The load sensing passage performs dual functions: it controls the relief valve for pressure management and simultaneously controls the pressure compensation valves for flow rate management. This universal passage design provides constant operability through pressure compensation while avoiding the need for separate control passages, thus reducing device complexity.

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

3Measurement precision

If separate passages are provided for relief valve and pressure compensation valve, then pressure control is improved, but assembly complexity increases

Engineering Contradiction:
Improvepressure controlVSAvoidassembly complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the relief valve control passage and pressure compensation valve control passage into a single load sensing passage. This passage guides both port pressure and load pressure to their respective components, simplifying the internal structure and reducing assembly complexity while maintaining precise pressure control through the coordinated action of main and secondary relief valves.

Inventive Principle:
Principle #5Merging (Combining)

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 configuration enables constant operability across functions with varying load pressures without depending on load pressures, reducing device size, part count, and assembly steps, while optimizing pressure control for simultaneous operations.

Implementation Method 1

check valves disposed in respective passages connecting the load handling lines of the plurality of fluid control valves other than the fluid control valve corresponding to the function requiring the maximum load pressure among the plurality of fluid control valves and the second passage

Methodology Applied
Scientific EffectCheck valve: Valve

Data Source

PatentEP3882472B1Fluid control device
Publication Date: 2023.12.27 SHIMADZU CORP
  • EP3882472B1 patent drawingFigure 1
  • EP3882472B1 patent drawingFigure 2
  • EP3882472B1 patent drawingFigure 3~4

AI summary

When a fluid control valve (2) is opened and closed, the port pressure of the fluid control valve (2) is guided to a main relief valve (6) through a first passage (101), and its maximum pressure is controlled by the main relief valve (6). At the same time, the port pressure of the fluid control valve (2) is guided to pressure compensation valves (21), (31), and (41) of the respective fluid control valves (2), (3), and (4). As a result, even when functions having different load pressures are simultaneously operated in the fluid control valves (2), (3), and (4), constant operability can be always secured without depending on the load pressures. In addition, when the fluid control valve (3), which drives a tilt cylinder (30) for a function of tilting a fork, is opened and closed, the port pressure of the fluid control valve (3) is guided to a secondary relief valve (7) through a second passage (102), and is also guided to the main relief valve (6) and the pressure compensation valves (21), (31), and (41) of the respective fluid control valves (2), (3), and (4) through the first passage (101).