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Treatment of the Failure of the Piston Rod of the Hydraulic Power Cylinder to Move

Ⅰ. Insufficient pressure of the piston rod of the hydraulic power cylinder


1. The oil does not enter the hydraulic power cylinder


(1) The reversing valve is not reversing;


(2) The system is not supplying oil.


2. Although the hydraulic power cylinder has oil, there is no pressure


(1) The hydraulic power cylinder system is faulty, and mainly the pump or overflow valve is faulty;


(2) The internal leakage is serious, the piston and the piston rod are loosened, and the seal is seriously damaged;


3. The pressure of hydraulic power cylinder does not reach the specified value


(1) The seal is aging or invalid, and the lip of the seal ring is installed reversely or is damaged;


(2) The piston ring of the hydraulic power cylinder is damaged;


(3) The set pressure of the system is too low;


(4) The pressure regulating valve is faulty;


(5) When the flow through the adjusting valve is too small and the leakage in the hydraulic power cylinder increases, the flow is insufficient, resulting in insufficient pressure;


(6) Check the reason why the reversing valve is not reversing and eliminate it;


(7) Check the failure causes of hydraulic pumps and main hydraulic valves and eliminate it;


(8) Check the cause of the failure of the pump or overflow valve of hydraulic cylinder component and eliminate it;


(9) Tighten the piston and piston rod and replace the seals;


(10) Replace seals of hydraulic power cylinder and install them correctly;


(11) Replace the piston rod;


(12) Readjust the pressure of hydraulic power cylinder until it reaches the required value;


(13) The flow rate of the regulating valve must be greater than the leakage in the hydraulic power cylinder.


Ⅱ. The pressure of the hydraulic power cylinder has reached the requirement but it still does not move


1. Problems with hydraulic power cylinder structure


(1) The end face of the piston is close to the end face of the cylinder barrel, and the working area is insufficient, so it cannot be started;


(2) The one-way valve circuit on the cylinder with a buffer device is blocked by the piston.


2. The piston rod of the hydraulic power cylinder cannot move smoothly


(1) The clearance between the cylinder barrel and the piston, the guide sleeve and the piston rod is too small;


(2) The matching clearance between the piston rod and the fabroil guide sleeve is too small;


(3) The hydraulic power cylinder is poorly assembled (such as poor coaxiality between the piston rod, piston and cylinder head, and poor parallelism between the hydraulic power cylinder and the worktable).


3. The cause of the hydraulic circuit


The cause of the hydraulic circuit is mainly that the oil in the back pressure chamber of the hydraulic power cylinder is not connected to the oil tank, the throttle of the speed control valve on the oil return line is adjusted too small, or the reversing valve connected to the return oil does not act.


(1) An oil groove should be added to the end surface of the hydraulic power cylinder to allow the working fluid to flow into the working end surface of the piston quickly;


(2) The oil inlet and outlet positions of the cylinder barrel of the hydraulic power cylinder should be staggered from the end face of the piston;


(3) Check the fit clearance of hydraulic cylinder components, repair the guide sleeve hole, and meet the required fit clearance;


(4) Reassemble and install hydraulic cylinder components, and replace unqualified parts.