Type Of Hydraulic Valve
Working principle of hydraulic valve
The hydraulic valve includes the valve core, the body and the drive spool in the valve body to make the relative motion device. In the hydraulic system is used to control the flow of fluid pressure, flow and direction, to ensure that the implementation of components in accordance with the requirements of the work. belongs to the control element
Basic working principle of hydraulic valve: Using the valve core in the valve body as relative movement to control the valve mouth and the size of the valve mouth, to achieve pressure, flow and direction control; and the flow through the valve mouth and the valve mouth before and after the pressure difference and valve area, always meet the pressure flow equation.
Hydraulic valve is used to control the flow direction of oil in the hydraulic system or adjust its pressure and flow, so it can be divided into directional valve, pressure valve and flow valve three categories. Hydraulic Valves A valve of the same shape can have different functions because of the different mechanism of action. Pressure valves and flow valves control the pressure and flow of the system using the throttling effect of the flow cross-section, while the directional valve controls the flow direction of the oil by using the change of the channel. That is to say, although there are various types of hydraulic valves, Hydraulic Valves there are some basic points of common between them.
Classification of hydraulic Valves
A component used in hydraulic fluid to control the flow and direction of a liquid pressure Shan. The control pressure is called the pressure control valve, the control flow is called the flow control valve, the control Shan breaks and the flow direction is called the directional control valve.
Pressure control valve: According to the use of the overflow valve Shan pressure reducing valve and sequential valves. (1) Overflow valve: Can control the hydraulic system to maintain a constant state when the pressure is reached. The overflow valve used for overload protection is called a safety valve. Hydraulic Valves When the system fails and the pressure rises to a limit that may cause damage, the valve opens and overflows to ensure the safety of the system. (2) The pressure reducing valve: Can control the branch circuit to obtain the stable pressures than the main circuit oil depresses. The pressure relief valve according to its control function is different, can be divided into the fixed value pressure reducing valve (output pressure is constant value) Shan fixed difference pressure reducing valve (input and output press difference is fixed value) and the fixed ratio relief valve (input and output pressure to maintain a certain proportion). (3) Sequential valve: Can make an executive component (such as hydraulic cylinder SHAN hydraulic motor, etc.) after the action, and then in order to make other components of the operation. The pressure produced by the pump first pushes the hydraulic cylinder 1 movement, while the inlet port of the sequential valve acts on area A, when the hydraulic cylinder 1 movement completely becomes, the pressure rises, the effect in area A's upward thrust is larger than the spring's adjustment value, the valve core rises causes the oil inlet and the outlet mouth to be interlinked, Hydraulic Valves causes the hydraulic cylinder 2 movement.
Flow control valve: By adjusting the throttle area between the valve core and the valve body and the local resistance it produces, the flow is adjusted to control the speed of the actuator. Flow control valve is divided into 5 kinds by use. (1) Throttle valve: After adjusting throttle area, can make the load pressure change little and the motion uniformity request is not high the movement speed of the component that basically maintains the stability. (2) Speed control valve: In the load pressure changes can maintain the throttle valve import and export pressure difference is fixed value. In this way, after the throttle area is adjusted, no matter how the load pressure changes, the speed control valve can maintain the flow through the throttle valve, so that the movement speed of the actuator is stable. (3) Shunt valve: Regardless of the load size, can make the same oil source of two of the executive components to obtain equal flow of the equivalent shunt valve or synchronous valve, the proportional distribution of the flow of the proportional shunt valve. (4) Set flow valve: The effect is opposite to the shunt valve, Hydraulic Valves the flow into the flow valve is proportional. (5) Shunt set flow valve: Both shunt valve and set flow valve function.
Directional control valve: According to the use of valves and reversing valve. Check valve: Only allow the fluid in the pipeline one-way connection, reverse is cut. Reversing valve: Changing the Shan-break relationship between different pipelines Shan according to the valve core in the valve body working position number two Shan three; according to the number of channels controlled two-pass Shan Tee Shan four-pass Shan five-pass, etc. according to the valve core driving mode, manual Shan motor Shan Electric Shan liquid movement and so on. Fig. 2 is the working principle of the three-bit four-pass directional valve. P is the oil outlet, Hydraulic Valves O is the oil outlet, and the A Bu is the export to the actuator. When the spool is in the middle, all the oil ports are cut off and the actuator is not moved; When the spool is moved to the right, p and a pass, B and O Pass; when the spool moves to the left, p and B pass, A and O. In this way, the executive component can be Shan reverse motion.
The material of the main parts of the valve body of the hydraulic valve should be first taken into account the physical properties (temperature, pressure) and chemical properties (corrosivity) of the working medium. At the same time, we should also understand the cleanliness of the medium (there is no solid particles). In addition, the relevant provisions and requirements of the State and the use of the department.
Many kinds of materials can meet the requirements of hydraulic valve body in a variety of different working conditions. However, the correct and reasonable choice of the hydraulic valve body material, Hydraulic Valves you can obtain the hydraulic valve body most economical service life and the best performance.