A component used to control the pressure, flow and direction of the liquid in a hydraulic transmission. Among them, the pressure control valve is called the pressure control valve, the flow control valve is called the flow control valve, and the flow control valve is called the directional control valve.
Pressure control valve: According to the purpose, it is divided into overflow valve, pressure reducing valve and sequence valve.
(1) Relief 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.
(2) Pressure reducing 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 a fixed value pressure reducing valve (output pressure is a constant value), a fixed difference pressure reducing valve (the difference between input and output pressure is a fixed value) and a fixed ratio pressure reducing valve (Maintain a certain ratio between input and output pressure).
(3) Sequence valve: After one actuator (such as hydraulic cylinder, hydraulic motor, etc.) is activated, other actuators can be activated in sequence. The pressure generated by the oil pump first pushes the hydraulic cylinder 1 to move, and at the same time acts on the area A through the oil inlet of the sequence valve. When the hydraulic cylinder 1 moves completely, the pressure rises, and the upward thrust acting on the area A is greater than the setting of the spring After the value is set, the spool rises to make the oil inlet communicate with the oil outlet, and the hydraulic cylinder 2 is moved.
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. Flow control valves are divided into 5 types according to their purposes.
(1) Throttle valve: After adjusting the area of the orifice, the movement speed of the actuator that has little change in load pressure and low movement uniformity can be basically kept stable.
(2) Speed control valve: It can keep the pressure difference between the inlet and outlet of the throttle valve at a constant value when the load pressure changes. In this way, after the orifice area is adjusted, no matter how the load pressure changes, the speed control valve can keep the flow rate through the throttle valve unchanged, so that the movement speed of the actuator is stabilized.
(3) Diverter valve: Regardless of the load, the two actuators of the same oil source can get the same flow as the equal divert valve or the synchronous valve; the proportional diversion valve is the proportional distribution of the flow.
(4) Collecting valve: The function is opposite to the diverting valve, and the flow into the collecting valve is distributed proportionally.
(5) Diverting and collecting valve: It has both functions of dividing valve and collecting valve.
Directional control valve: Divided into one-way valve and reversing valve according to purpose.
One-way valve: Only allow the fluid to be connected in one direction in the pipeline, and cut off in the reverse direction.
Reversing valve: change the on and off relationship between different pipelines, according to the working position of the valve core in the valve body, divided into two, three, etc.; according to the number of controlled channels, divided into two, three, four, Five-way, etc.; according to the spool drive mode, it is divided into manual, motorized, electric, hydraulic, etc.
Post time: May-27-2021