How to handle runaway speed of Manifold Block hydraulic system
In front of the introduction of “electromagnetic relief valve common fault cause analysis”, “typical fault diagnosis and troubleshooting methods of the pioneer relief valve”, “solenoid valve common faults and solutions”, today to introduce how to do the hydraulic system speed out of control.
The speed (speed) of the hydraulic system is out of control, mainly manifested in the slow speed, the speed is not adjustable, the speed is unstable, crawling and so on.
Slow speed of hydraulic system:
There are many reasons for the slow movement of the system. The main reasons are:
Hydraulic pump wear, volume efficiency decreased.
Reversing valve wear, resulting in internal leakage.
The relief valve adjusts the pressure too low, so that a large amount of oil back to the tank through the relief valve.
Actuator wear, resulting in internal leakage.
There are undiscovered leaks in the system.
The throttle valve or speed control valve in series in the circuit is not fully opened, or other reasons to make the oil circuit is not smooth.
The load on the system is too large to push.
Hydraulic system speed is not adjustable
This kind of problem is generally caused by the flow control valve stuck, rust dead and other reasons. The electro-hydraulic proportional speed control valve cannot adjust the speed of the system if the electrical signal can not be adjusted
The speed of the hydraulic system is unstable
The main causes of such problems are:
The change of temperature leads to the change of the leakage amount, which leads to the change of the flow rate of the available load, which is similar to the situation that the change of temperature leads to the change of the system pressure.
The throttling port of throttle valve has a low speed stability problem, which is related to the structure of throttling port, hydraulic oil pollution and other factors.
After the hydraulic system is mixed with air, the gas is compressed under high pressure. When the load is relieved, the pressure of the system drops, and the compressed gas expands rapidly, making the speed of the hydraulic actuator soar
The crawling of actuator is a common problem in hydraulic system. “Crawl” refers to the slow and intermittent motion of hydraulic execution. The main causes of crawling are:
Oil mixed with air, resulting in slow action of the actuator, response lag.
The pressure is too low, or not high, or drift down. When the load plus the sum of various resistance and hydraulic pressure is roughly the same, the actuator appears to be moving.
Excessive fluctuation of pressure and flow in the system causes uneven movement of the actuator.
When the hydraulic system is worn seriously, the internal leakage increases significantly as the working pressure increases. The speed of the execution is normal when it is not loaded, and the speed decreases immediately when it is loaded. For example, the main table of the surface grinder is moving at a normal speed when the workpiece does not touch the grinding head. Once the grinding head is touched, the speed becomes very slow. Guide rail and hydraulic cylinder movement direction is not parallel, or guide rail hair, poor lubrication conditions, large resistance, the hydraulic cylinder movement is difficult and unstable.
Circuit disorder can also lead to poor motion state of the actuator. For example, when the travel switch contact is bad, the electrical signal supplied to the electromagnet may also be intermittent, which causes the reversing valve can not be opened reliably, and the motion of the actuator is unstable.
Summary of working principles of several common hydraulic equipment: