Hydraulic control valve in addition to fill oil loop used in balance, order, packing, and often used in fixing a vertical hydraulic cylinder (load) or push rod movement as well as the implementation of the directional control valve lift logic element, which is often the hydraulic control valve is an important component in hydraulic system to meet the requirements of the characteristics of the load causes, control effect of other components is irreplaceable.

In the pressure system, the hydraulic control check valve achieves logical directional control. It needs a good opening pressure characteristic, the opening pressure, the time delay change is small, and the instantaneous opening is sensitive. In the self holding system, the load should be kept in the stop position for a long time, and the piston (load) can be locked in any position, and the hydraulic check valve should have reliable locking and locking position accuracy. Sometimes in a system, it also requires good open and locked pressure control characteristics. Opening and locking are important characteristics of the hydraulic control check valve in the application of the control circuit.

2, open the locking pressure control characteristic analysis of hydraulic system with single piston hydraulic cylinder as the actuator, the different installation positions of different cavity as the main working chamber and a hydraulic control valve in the circuit, the circuit performance are very different, especially the opening and locking characteristics of the system have different changes. Taking the pressure system and the load self retaining system as an example, the different opening and locking pressure characteristics are analyzed by the common oil inlet and return circuit system. Two system hydraulic cylinder geometry parameter 2.1 enters the oil way application characteristic analysis to show, the load self maintenance system widely applies in the balance circuit, the locking loop and the pressure maintaining and so on in the loop. The balance circuit can be regarded as vertical placement of hydraulic cylinders. The throttling valve indicates the return resistance, and the hydraulic control check valve has one end of the rod cavity in the hydraulic cylinder.

The oil inlet requirements of check valve in the hydraulic cylinder vertical and vertical motion of parts due to weight and self fall, stop or slow down the piston piston due to weight and accelerate whereabouts; or the hydraulic cylinder is fixed on any position, to prevent the hydraulic cylinder because of high load and reduce the pressure of the loop movement. The characteristics of the pressurization (intensification) and the no-load control pressure of the system have been analyzed and the results are given. The characteristics of the pressure control of the opening and locking are analyzed as follows.

Bachelor degree, mainly engaged in fluid transmission and control research.

Hydraulic and pneumatic opening pressure depends on the pilot control pressure control, pressure from the top of the load in the single self maintenance system, the N value must be greater than 1. to open the valve, reverse flow of oil, the mechanical characteristics of circuit equation: describes the opening and locking control valve characteristics, N value is not too small, A\ the hydraulic cylinder piston rod m2 area, Ar area, M2 K per unit area of the spring force, the control piston area of NAc valve, M2 A2 core confined area in M2 solution (1) a Ar hydraulic control valve leakage control is small regardless of the piston, the pilot control pressure Pc*K hydraulic control valve is not open and by the formula to calculate the minimum limit value of available N critical formula, otherwise the valve opening is required to control the pressure higher than the required pressure caused by unsafe factors system. The R ratio is also an important parameter, which describes the mechanical characteristics of the system in conjunction with the N value. The determination of the R ratio, on the one hand determines the size of the hydraulic cylinder, on the other hand, it also indirectly affects the opening and locking performance of the valve. In the hydraulic system, when the piston rod is pulled, it is usually 3.33. When the pressure is high, the small value is taken; when the pressure is low, the big value is taken. When the piston rod is pressed, consider the stability of the piston rod, generally take D/d=1.33 ~2., if the hydraulic cylinder stroke speed is larger, in order to prevent hydraulic impact, special design should be carried out.

The return line opening and locking system figure K value is generally 140kPa, system parameter type (2) analysis steps can N open analysis of =2.667:1 2.2 oil application characteristics of the system has shown similar to the oil inlet system, the mechanical properties of the equation: with the same, the system parameters of type (3) to N open the two = different working system, need to use a different hydraulic control valve or adjust the different pilot control pressure. When the 1 conditions used in pressure system, open the N value must be greater than 2667:1; when the condition 2 using 3 conclusions based on the pressure system and the load from N and R analysis system is established to maintain, measure and evaluate the hydraulic control valve to open and lock the pressure control characteristic of the important parameters and basis. General industrial hydraulic cylinder R range 1.75~ 10, even if there are special conditions, the value should not be less than 1.15, because the low R value will increase the N value. The general N range is 1. 5:1~4:1, even if the R is close to the limit value, the N value should not be too much, beyond the range of values. In practical application, the hydraulic control check valve, which is closest to the theoretical calculation value, can better meet the system requirements.