Troubleshooting and maintenance of gear pump
Troubleshooting and maintenance of gear pump
(1) The hydraulic pump shaft is broken or severely worn.
1) The mechanical performance of the pump shaft fails to meet the requirements. In the design, material selection or processing, the selected materials can not meet the required mechanical properties or the heat treatment process is not good, and the pump will be broken under the action of large force and torque during operation. 40Cr material shall be selected as the pump shaft, and the heat treatment hardness value is hrc52.
2) When the pump is working, the gear is stuck by foreign matters, the transmission torque is too large, and the pump shaft is broken. Find out the reasons for the entry of foreign matters, clean them in time, and process and reassemble them according to the pump shaft drawing.
3) When the pump is working, the needle roller bearing is burned due to poor lubrication and the pump shaft is worn. Timely check the causes of poor lubrication and refit the shaft.
(2) The gear pump does not rotate flexibly or bites.
1) Axial clearance and radial clearance are too small. Generally, a clearance of 0.025 ~ 0.04mm shall be reserved between the gear end face and the pump cover, and a clearance of 0.13 ~ 0.16mm shall be reserved between the tooth top circle and the hole in the pump body. It shall be measured carefully during inspection. If it does not meet the requirements, the clearance shall be reconfigured.
2) Impurities in the oil are sucked into the pump body. Timely check and remove impurities.
3) Poor assembly, CB type cover plate, poor concentricity with the shaft, too long spring fastening foot of the long shaft, and poor quality of needle roller sleeve. Reassemble as required.
4) The coaxiality of the coupling between pump and motor is not good. The coaxiality shall be within 0.1mm, strictly prevent the surrounding dust, iron filings and cooling water from entering the oil pool, and keep the oil clean.
5) The position of the screw hole of the front cover is wrong with that of the through hole of the rear cover of the pump body (the displacement is not good). After tightening the screws, do not rotate with force. At this time, the hole of the rear cover of the pump body can be appropriately enlarged with a drill or a round file before assembly.
(2) The gear pump is hot.
The above (2) failure causes of inflexible rotation or seizure of the gear pump are also caused by heating of the gear pump, so the troubleshooting methods can be implemented with reference. In addition:
① The oil viscosity does not meet the requirements. Select appropriate hydraulic oil;
② Serious friction between side plate and shaft sleeve and gear end face;
③ The cooling measures of hydraulic system oil are not good. If there are no cooling facilities in the hydraulic system, plus the high ambient temperature, or the hydraulic oil tank is too small, or the hydraulic system works continuously for a long time, the oil temperature will rise, resulting in the heating of the hydraulic pump, which shall be handled according to the actual situation.
