Fault analysis and troubleshooting of radial plunger hydraulic motor
Fault analysis and troubleshooting of radial plunger hydraulic motor
The common faults are: the speed drops and the speed is not enough; Insufficient output torque; The hydraulic motor does not rotate or work; Unstable speed; Oil leakage (external leakage) at the shaft seal of hydraulic motor. The fault cause analysis and troubleshooting methods are as follows.
1. The speed drops and the speed is not enough
(1) The valve distribution shaft is worn or the fitting clearance is too large. Hydraulic motors with valve distribution shaft mainly include JMD type, cljm type, ym-3.2 type, etc. When the valve distribution shaft is worn, the clearance between the valve distribution shaft and the matching hole (such as valve sleeve or fluid distribution shell hole) increases, resulting in increased internal leakage and pressure oil leakage to the oil discharge chamber, reducing the flow into the plunger chamber and the speed. At this time, the outer cylindrical surface of the valve distribution shaft can be brushed or plated with hard chromium for repair. If the situation is serious, it needs to be reprocessed and replaced.
(2) The end face of the valve plate is worn and has grooves. The hydraulic motors with port plate mainly include jmdg type, NHM type, etc. When the end face of the valve plate is worn, especially when there is a groove, the internal leakage increases and the speed decreases; In addition, the failure of pressure compensation clearance mechanism also causes this phenomenon. At this time, the end face of the port plate should be ground or ground.
(3) The sealing ring on the plunger is damaged. After the sealing ring on the plunger is damaged, the seal between the plunger and the cylinder bore fails and the internal leakage increases. Replace the sealing ring at this time.
(4) The cylinder block hole has deep grooves due to dirt and other reasons, which should be replaced.
(5) The connecting rod ball joint pair is worn.
(6) System reasons. For example, insufficient oil supply of the hydraulic pump, too high oil temperature, too low oil viscosity and too large back pressure of the hydraulic motor will all cause the phenomenon of insufficient rotation speed of the hydraulic motor. The causes can be found out and countermeasures can be taken.
2. Insufficient output torque
(1) (1) to (6) in the same 1.
(2) The ball joint of the connecting rod is burned. Don't try hard.
(3) The connecting rod bearing bush is burnt out, resulting in increased mechanical friction resistance.
(4) The bearing is damaged, resulting in poor rotation.
Corresponding measures can be taken for the above reasons.
3. The hydraulic motor does not rotate or work
(1) If there is no pressure oil entering the hydraulic motor, or the pressure of the pressure oil entering the hydraulic motor is too low, check the reason why the system pressure does not come.
(2) The cross connecting shaft between the output shaft and the valve plate is broken or missing, and should be replaced or reinstalled.
(3) A column plug is stuck in the cylinder block hole and the pressure oil cannot be pushed. It should be disassembled and repaired to make it move flexibly.
(4) The bearing on the output shaft is burned, and the bearing can be replaced.
4. Unstable speed
(1) There is force difference between moving parts.
(2) The input flow is unstable. If the flow of the pump changes too much, check it.
(3) The lubricating oil film on the moving friction surface is damaged, resulting in dry friction, especially shaking (crawling) at low speed. At this time, pay most attention to check the blockage of the throttle hole in the center of the connecting rod, and clean or change the oil.
(4) There is no back pressure regulating device or back pressure at the outlet of hydraulic motor. At this time, due to the influence of load change and large speed change, adjustable back pressure should be set.
(5) Large load change or oil supply pressure change.
5. Oil leakage (external leakage) at the shaft seal of hydraulic motor
(1) The oil seal is clamped, the spring on the lip falls off, or the oil seal lip is strained.
(2) The internal leakage of the hydraulic motor is large, resulting in the pressure rise of the oil leakage in the shell, which is greater than the sealing capacity of the oil seal.
(3) The back pressure of the hydraulic motor drain port is too high.
The above reasons can be handled.
