Hydraulic Drive Circuit Layout for Stable Multi-Cylinder Operation
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Solution Overview
Problem
In work machines like hydraulic excavators, the combination of open and closed hydraulic circuits leads to unstable hydraulic oil flow rates when multiple single rod hydraulic cylinders are driven simultaneously, resulting in degraded operability due to insufficient supply pressure and flow rate fluctuations.
Innovation Solution
A driving device with multiple closed circuits and open circuits, featuring a controller that manages hydraulic oil flow through closed-circuit and open-circuit hydraulic oil outflow/inflow control sections, and an open-circuit switching section, ensuring stable hydraulic oil supply to single rod hydraulic cylinders by connecting the open-circuit switching section's outflow to closed circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hydraulic oil is distributed from an open circuit to multiple closed circuits, then the moving speed of single rod hydraulic cylinders increases, but the flow rate becomes unstable and supply pressure becomes insufficient during combination operation
Solution Approach 1:
The hydraulic system is segmented into multiple independent closed circuits (first closed circuit with first hydraulic pump and first hydraulic cylinder, second closed circuit with second hydraulic pump and second hydraulic cylinder) rather than using a single distributed system. Each closed circuit independently supplies hydraulic oil to its respective hydraulic cylinder, ensuring stable flow rate and supply pressure during combination operation while maintaining high moving speed.
2Adaptability or versatility
If multiple single rod hydraulic cylinders are driven simultaneously from one open circuit, then operational versatility increases, but the hydraulic oil supply becomes insufficient and behavior becomes unstable
Solution Approach 1:
The system divides the hydraulic power supply into multiple independent closed circuits, each with its own hydraulic pump and control mechanism. This segmentation allows multiple hydraulic cylinders to operate simultaneously with stable hydraulic oil supply, maintaining ease of operation during combination operations while enabling versatile operational modes.
Solution Approach 2:
Each closed circuit is designed with universal functionality to supply hydraulic oil to its corresponding hydraulic cylinder independently. The multiple closed circuits work together as a unified system that can handle various combination operations, providing both versatility and operational stability simultaneously.
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 stabilizes the behavior of single rod hydraulic cylinders and improves their operability by ensuring reliable hydraulic oil supply, even during simultaneous operation, by controlling the open-circuit hydraulic oil outflow/inflow control sections and switching sections to prevent flow rate shortfalls.
Implementation Method 1
a hydraulic pump being a pressure generating source is connected directly to a single rod hydraulic cylinder being a hydraulic actuator
Implementation Method 2
the hydraulic oil after used in driving the single rod hydraulic cylinder to perform a given work is returned directly to the single rod hydraulic cylinder
Data Source
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AI summary
To provide a driving device capable of improving the operability of a plurality of single rod hydraulic cylinders. The present invention takes a construction provided with a closed circuit A in which first and third hydraulic pumps 12, 14 and a boom cylinder 1 are connected through selector valves 43a, 45a in a closed-circuit fashion, a plurality of open circuits E, F provided with second and and fourth hydraulic pumps 13, 15 and selector valves 44a, 46a that switch the supply destinations of hydraulic oils flowing out from the second and and fourth hydraulic pumps 13, 15, and a connection passage 301 connected to sides of the selector valves 44a, 46a from which sides hydraulic oil flows out, and connected to the closed circuit A.