Analysis of the causes of underspeed failure in the four-column cutting machine:
When the work is being fed, the working feed rate is significantly reduced under load, even if the opening control valve is opened. Under the load, the working pressure is increased, the leakage is increased, and the adjusted speed is reduced due to the increase of internal and external leakage. The system oil temperature is increased, the viscosity of the oil is reduced, the leakage is increased, and the effective flow rate is reduced. The design of the hydraulic system is unreasonable. When the load changes, the flow rate of the actuator entering the hydraulic device also changes, causing a change in speed. The oil is mixed with impurities, blocking the throttle valve of the flow regulating valve, causing the working speed to decrease; when the block is blocked, the speed is unstable. Air has been introduced into the hydraulic system. The reason why the speed of rapid movement is not enough is as follows: the relief valve is permanently deformed by the spring or misplaced into a weak spring, the main spool damping 孑L is partially blocked, and the main spool is stuck in the position of the small opening, causing the pressure of the hydraulic pump output. This phenomenon can also occur with partial oil spills. The output flow of the hydraulic pump is not enough and the output pressure is not high. The resistance is fast when the fast forward is large, for example, the guide rail is lubricated and the oil is cut off, the guide plate of the guide rail is too tightly adjusted, the installation accuracy of the hydraulic cylinder and the assembly precision are poor, and the frictional resistance is increased when fast forward.
The elimination of the underspeed of the four-column cutting machine eliminates the failure of the hydraulic pump output flow and the output pressure is not high. Clean parts such as flow valves. When the oil is seriously polluted, change the oil in time. Eliminate the failure caused by the pressure valve such as the relief valve. Find the location of internal and external leaks, eliminate internal and external leaks, and replace worn parts to eliminate internal leaks. Identify the cause of the hydraulic system intake and eliminate the air in the hydraulic system.