REXROTH Rexroth proportional valve classification description

Introduction to the classification of REXROTH Rexroth proportional valve The German Rexroth proportional valve is another type of continuous control: the valve port can open any opening according to the need, thus controlling the flow rate. These valves are manually controlled, such as throttle valves. There are also electronic controls, such as proportional valves and servo valves.
REXROTH Rexroth proportional valve proportional valve or servo valve is designed to achieve throttling control of flow by electronic control (of course, structural changes can also achieve pressure control, etc.), since it is throttling control, there must be energy loss The servo valve differs from other valves in that it has a greater energy loss because it requires a certain amount of flow to maintain the pre-stage control circuit.
German Rexroth REXROTH proportional valve is generally the same as the reversing valve, but the reversing of the spool is not driven by the electromagnet, but by the hydraulic pressure output from the pre-stage valve. The liquid reversing valve is similar, except that the pre-stage valve of the electro-hydraulic reversing valve is an electromagnetic reversing valve, and the pre-stage valve of the servo valve is a nozzle flapper valve or a jet tube valve with better dynamic characteristics.
The German Rexroth REXROTH proportional valve means that the main valve of the servo valve is controlled by the output pressure of the pre-stage valve, while the pressure of the pre-stage valve comes from the inlet p of the servo valve. If the pressure of the p-port is insufficient, The pre-stage valve cannot output enough pressure to push the main spool.
The German Rexroth REXROTH proportional valve has many disadvantages: high energy consumption, easy failure, poor resistance to pollution, high price, etc. There is only one benefit: dynamic performance is the highest among all hydraulic valves. With this advantage, servo valves have to be used in many situations where dynamic characteristics are required, such as servo control of aircraft rockets, turbine speed regulation, and the like. The dynamic requirements are lower, basically the world of proportional valves. Generally speaking, it seems that the servo system is closed-loop control, and the ratio is mostly used for open-loop control. Secondly, there are many types of proportional valves, such as proportional pressure and flow control valves. The control is more flexible than the servo medicine. From their internal structure, the servo valve is mostly zero-covered, the proportional valve has a certain dead zone, the control precision is low, and the direction should be slow. However, from the development trend, especially in the proportional flow control valve and servo valve, the performance difference between the two is gradually narrowing. In addition, the cost of the proportional valve is much lower than that of the servo valve, and the anti-pollution ability is also strong! The thread of the German Rexroth REXROTH proportional valve will be used to fix the components on the oil manifold block. The screw-in cartridge valve has the characteristics of flexible application, saving pipeline and low cost. In recent years, the application of engineering machinery has become more and more extensive. Commonly used spiral insert type proportional valves are in the form of two-way, three-way, four-way and multi-pass, two-way proportional valve main proportional throttle valve, which often forms a composite valve together to control flow and pressure; The main proportional valve main proportional pressure reducing valve is also used in the mobile mechanical hydraulic system. It mainly operates the pilot operated oil circuit of the hydraulic operating multi-way valve. The three-way proportional pressure reducing valve can replace the traditional manual decompression pilot valve, which has more flexibility and higher control precision than the manual pilot valve. It can be made into the proportional servo control manual multi-way valve as shown in Fig. 1. Different input signals and pressure reducing valve make the output piston have different pressure or flow rate to realize the proportional control of the displacement of the multi-way valve spool. The four-way or multi-pass spiral-injection proportional valve allows for individual control of the work unit.
Germany Rexroth REXROTH proportional valve is a switch control: either fully open or fully closed, the flow is either the largest or the smallest, no intermediate state, such as ordinary electromagnetic straight-through valve, electromagnetic reversing valve, electro-hydraulic reversing valve. The movement of the Rexroth proportional valve spool is controlled by a proportional solenoid that causes the output pressure or flow to be proportional to the input current. Therefore, the pressure and flow can be continuously controlled by changing the input electrical signal. Some valves also have the function of controlling the flow size and direction. According to the function Rexroth proportional valve can also be divided into three categories: pressure valve, flow valve and reversing valve.
Rexroth proportional valve
The movement of the spool of the German Rexroth proportional valve is controlled by a proportional electromagnet, so that the output pressure or flow is proportional to the input current. Therefore, the pressure and flow can be continuously controlled by changing the input electrical signal. Some valves also have the function of controlling the flow size and direction. Rexroth proportional valves can be divided into three categories according to their functions: proportional flow valve, proportional pressure valve and proportional reversing valve. There are two main types of electro-hydraulic proportional valves divided by structure: one is a spiral-type proportional valve (screwin cartridge proportional valve), and the other is a spool proportional valve.