Knowledge Sharing Of Hydraulic Excavator Monoblock And Sectional Directional Control Valves

Knowledge sharing of hydraulic excavator monoblock and sectional valves

Monoblock and sectional valve is a directional control valve with an integrated structure that combines a reversing valve and a number of auxiliary devices to control the oil flow in multiple directions. It has the advantages of compact structure, simple pipeline and convenient operation.
As a direction control device, it is mainly used in hydraulic systems such as construction machinery, mining and metallurgical machinery, lifting and transporting machinery, and light industrial machinery. Auxiliary devices mainly include valve components such as main relief valve, overload relief valve, supplementary valve, etc. Most of these valves use small-sized cartridge components. They are selected according to the requirements of the host and have a great impact on the performance of the multi-way valve.

At present, there are many types of multi-way valves. In summary, they are divided into two types: integral type and combined type.

1) Integral multi-way valve The spool valve and various valve components of the integral multi-way valve are all installed in the same valve body. It has a compact structure, light weight, and relatively small pressure loss, but the valve body casting process is complex and poor versatility. It adopts an integral type when mass production and fewer connections.

2) Combined multi-way valveThe combined multi-way valve is composed of the front cover of the oil inlet, the back cover of the oil return and the assembly of each valve body. It can be assembled into different numbers of passages according to different usage requirements. It has strong versatility, but each It is easy to leak oil and has a large volume. The early development of the multi-way valve was a manual six-way multi-way valve. This valve is: first throttling the bypass and then the full flow of the oil source enters the system through the main valve port of the multi-way valve. It has a certain proportional control performance, but the proportional control range decreases with the increase of system pressure.

Aiming at the shortcoming of unstable operation of the six-way multi-way valve that is easily affected by the pressure difference when the load changes, the researchers developed a four-way multi-way valve with pressure compensator based on the principle of the two-way speed control valve.

In the 1980s, the maturity and wide application of electro-hydraulic proportional technology promoted the application of electro-hydraulic proportional multi-way valves. The two-way pressure compensator used in each connection for nearly 30 years was used to achieve load pressure compensation, and fixed differential overflow The valve or load-sensing pump realizes load-sensitive control. When the flow of the pump is saturated, that is, when the demand flow of the actuator exceeds the maximum flow of the pump, the output pressure of the pump decreases, which reduces the flow entering the highest pressure and the load, and the speed decreases, and enters other loads. The flow rate remains unchanged. This cannot meet the requirement of simultaneous operation of multiple cylinders in engineering.

The application of hydraulic technology in construction machinery in the 21st century has become more and more extensive. As an important component of the hydraulic system of construction machinery, the multi-way valve is not only continuously improved on the basis of the existing structure, but also more important is the transplantation of technical achievements in other fields, such as electronic technology, computer technology, information technology, automatic control technology, friction and wear technology and New materials, new processes, etc., have further developed construction machinery products in the direction of energy saving, high efficiency, high reliability and environmental protection, while China is still in its infancy. For the load port sensitive to the electro-hydraulic load, the system structure design, the shunt control method and the decoupling control method of mutual interference between the various actuators are independently controlled to the load port of the electro-hydraulic load, so as to save the system energy to the maximum extent and realize the system Stability and rapidity have become research hotspots.

Hanjiu Technology, hydraulic experts around you, if you encounter any hydraulic related problems, please contact us