Valve inspection equipment Three-way four-way and three-position five-way reversing slide valve for various operation methods. When the spool is in the center orientation, the connection status of each oil port is called the median function of the valve inspection equipment. Commonly used are "O" type, "H" type, "P" type, K" type, "M" type and the like.
When dissecting and selecting the median function of the three-position valve inspection equipment, consider human:
(1) System holding pressure When the P port is blocked, the system is kept in pressure and the hydraulic pump is used in the multi-cylinder system.
(2) Unloading of the system P port is connected to the T port with hysteresis, and the system is unloaded. (H K X M type)
(3) Commutation smoothness and accuracy Both A and B are blocked. The reversing process is prone to impact. The commutation is not stable, but the accuracy is high. Both A and B ports are connected to the T port. The commutation is stable but the accuracy is low.
(4) Start smoothness When the valve is in the neutral position, a certain cavity of the hydraulic cylinder is connected to the fuel tank. When the valve is started, there is not enough oil to buffer, and the start is not stable.
(5) Hydraulic cylinder floats and breaks in any orientation
2) Hydraulic power of the spool valve
According to the momentum law of the liquid flow, when the oil passes through the valve inspection device, the hydraulic power on the valve core has two kinds of steady-state hydraulic power and transient liquid power.
1) Steady-state hydraulic power: After the valve core is moved, after the tooth is fixed, the flow of the liquid flows through the valve port due to the change of the dynamic force, and the result is that the valve has a tendency to close the valve port, which is related to the flow rate of the valve.
2) Transient hydraulic power: During the movement of the spool valve, the force of the valve cavity fluid flow on the spool due to acceleration or deceleration is related to the moving speed.
Hydraulic clamping appearance
Clamping the matter: the dirt enters the crack; the temperature rises, the valve core swells; but the primary notice is the result of the radial dissatisfaction caused by the slight shape and concentricity of the slide valve.
There is no shape error between the valve core and the valve inspection equipment. The axis is parallel but not coincident.
b The spool has a reverse cone due to machining errors, and the axis is parallel but not coincident
c The valve plug has a partial protrusion
Reduce the radial unbalanced approach:
1) Progressive production and assembly accuracy
2) Open the annular pressure equalization groove on the valve check device spool