The hydraulic system includes: directional control valve, pressure control valve and flow control valve.
Pressure control valve: According to the purpose, it is divided into overflow valve, pressure reducing valve and sequence valve. ①Relief valve: It can control the hydraulic system to maintain a constant state when the set pressure is reached. The relief valve used for overload protection is called a safety valve. When the system fails and the pressure rises to a limit value that may cause damage, the valve port will open and overflow to ensure the safety of the system. ②Reducing valve: It can control the branch circuit to obtain a stable pressure lower than the oil pressure of the main circuit. According to the different pressure functions it controls, the pressure reducing valve can be divided into fixed pressure reducing valve (output pressure is a constant value), fixed differential pressure reducing valve (input and output pressure difference is a fixed value) and fixed ratio pressure reducing valve (Maintain a certain ratio between input and output pressure). ③Sequence valve: After one actuator (such as hydraulic cylinder, hydraulic motor, etc.) is activated, other actuators can be activated in sequence.
Flow control valve: adjust the flow rate by adjusting the orifice area between the valve core and the valve body and the local resistance generated by it to control the movement speed of the actuator.
Directional control valve: According to the purpose, it is divided into one-way valve and reversing valve. ①One-way valve: only allow the fluid to be connected in one direction in the pipeline, and cut off in the reverse direction. ②Reversing valve: change the on and off relationship between different pipelines, according to the working position of the spool in the valve body, divided into two, three, etc.; according to the number of channels to be controlled, divided into two, three, four , Five-way, etc.; such as two-position two-way, three-position three-way, three-position five-way, etc. According to the spool drive mode, it is divided into manual, motorized, electromagnetic, hydraulic, etc.