What Is a Directional Control Valve?

The hydraulic valve is used to control the flow direction of the oil in the hydraulic system or adjust its flow rate and pressure. As a type of hydraulic valve, the directional control valve controls the flow direction of the oil by replacing the flow channel. The types of directional control valves include check valves, hydraulic check valves, reversing valves, stroke reducing valves, filling valves, shuttle valves, and so on.

Directional control valve

(Check valve or check valve)

Function: Only allow the oil to flow in the forward direction, and not allow it to flow back. ^[1]

Classification: straight-through, right-angle

Structure: valve body, valve cone, steel ball, spring, etc.

Working principle: When the fluid flows from the oil inlet, the spring contracts under the action of hydraulic force, and the valve port is opened.

Opening pressure: 0.040.1MPa

Back pressure valve: Pk = 0.20.6 MPa

Directional control valve

Function: forward circulation, reverse controlled circulation

Directional control valve

Structure: ordinary check valve + hydraulic control device

Working principle: K does not pass pressure oil, and works in the same way as a normal check valve; K passes pressure oil, and the valve port is opened for reverse circulation

Application: Hydraulic check valve has good anti-sealing performance

Commonly used for holding, locking and balancing circuits

Directional control valve

Equivalent to a combination of two check valves

It has logic "OR gate" function. It is widely used in logic loop and program control loop, and it is commonly used in manual --- automatic loop conversion.

Because the shuttle valve has a path through during the reversing process, when the intake or exhaust volume of a certain interface is very small, the pressure difference between the forward and backward of the valve cannot be generated, so that the valve cannot be completely changed. Stopped halfway, causing the valve to malfunction. Therefore, when using it, be careful not to use a reducing joint at a certain interface to cause the path to be too small.

Directional control valve

AND gate function

Directional control valve quick exhaust valve

Function: It is used to speed up the cylinder movement speed for fast exhaust.

Under a given condition, the cylinder disinfection depends on the size of the control valve. If you need to increase the speed (especially when you need to increase the one-way speed), you can install a fast exhaust valve without having to bear the cost.

Directional control valve slide valve directional valve

(1) Structure and working principle of directional valve

structure:

Body: Cylindrical hole with multi-level undercut

Spool: Cylinder with multiple circular grooves

(2) Classification

Divided by the number of working positions: two, three, four, etc. Position: The number of working positions of the valve core relative to the valve body.

Divided by the number of channels: two links, three links, four links, five links, etc. ON: Number of main ports for external connection of valve body

Divided by control method: electromagnetic directional valve, hydraulic directional valve, electro-hydraulic directional valve, motorized directional valve, manual directional valve

Main structure of slide valve type reversing valve

Graphic symbol meaning:

1. Bitsrepresented by squares, a few are several squares

2. Pass, The head and tail of the arrow and the interception symbol have several intersections with a square.

3. The oil port has a fixed orientation and meaning, p-oil inlet (bottom left), T-oil return port (bottom right), AB-working oil port (left and top right) connected to the actuator.

4, spring-W, M, painted on both sides of the grid

5. Normal position-In the schematic diagram, the oil circuit should be connected to the normal position. Such as the three-position valve in the middle one compartment.

The neutral position of the spool valve: that is, when the spool valve is in the normal state, there are M type, H type, O type, P type, M type, etc.

(3) Main performance of directional valve

1) Reliable work

2) Low pressure loss

3) Small internal leakage

4) Commutation time and reset time

5) Long service life

(4) Common operation methods

1.Manual

2.Mobility

3.Electromagnetism

4, hydraulic