Multi way valve is a direction control valve with integrated structure, which is composed of directional valve and several auxiliary devices to switch the direction of oil flow. 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 engineering machinery, mining and metallurgical machinery, hoisting and transportation machinery and light industrial machinery. Auxiliary devices mainly include main relief valve, overload relief valve, oil makeup valve and other valve components. Most of these valves use plug-in components with small structural size. They are selected according to the requirements of the main engine, which has a great impact on the performance of the multi-channel valve.
At present, there are many structures and models of multi-channel valves. To sum up, they are divided into integral type and combined type.
1) Integral multi-way valve the slide valve and various valve components of the integral multi-way valve are installed in the same valve body. The utility model has the advantages of compact structure, light weight and small pressure loss, but the casting process of the valve body is complex and the universality is poor. When the mass production and the number of connections are small, the integral type is adopted
2) Combined multi-way valve combined multi-way valve is composed of oil inlet front cover, oil return rear cover and various valve bodies. It can be assembled into different channel numbers according to different use requirements. It has strong universality, but it is easy to leak oil between each connection and has large volume. In the early development of multi-way valve, it was a manual six-way multi-way valve. This valve is to throttle the bypass first, and then the full flow of oil source enters the system through the main valve port of multi-way valve. It has certain proportional control performance, but the proportional control range decreases with the increase of system pressure.
In view of the disadvantage that the pressure difference of six-way multi-way valve is easy to affect the unstable operation when the load changes, the researchers developed a four-way multi-way valve with pressure compensator according to the principle of two-way speed regulating valve.
In the 1980s, the maturity and wide application of electro-hydraulic proportional technology promoted the application of electro-hydraulic proportional multi-channel valve. In each unit that has been used for nearly 30 years, two-way pressure compensator is used to realize load pressure compensation, and constant differential overflow valve or load sensitive pump is used to realize load sensitive control. When the flow of the pump is saturated, that is, the demand flow of the actuator exceeds the maximum flow of the pump, The decrease of pump output pressure reduces the flow and speed into the highest pressure combined load, while the flow into other loads remains unchanged. This can not meet the requirements of multi cylinder simultaneous operation in engineering.
In the 21st century, hydraulic technology is more and more widely used in construction machinery. As an important component of the hydraulic system of construction machinery, in addition to continuous improvement on the basis of the existing structure, it is more important to transplant the technical achievements in other fields, such as electronic technology, computer technology, information technology, automatic control technology, friction and wear technology, new materials and new processes, so as to further promote the construction machinery 名媛直播 to energy conservation, high efficiency High reliability and environmental protection, while China is still in its infancy. For the load port sensitive to charged hydraulic load, the system structure design, shunt control method and decoupling control method of independent control of electro-hydraulic proportional multi-channel valve have become a research hotspot in order to save system energy to the greatest extent and realize the stability and rapidity of the system.
