Hydraulic pump: Straight shaft swash plate piston pump is divided into pressure oil supply type and self priming type. The pressure oil supply type hydraulic pumps mostly use a pneumatic oil tank, and there are also hydraulic pumps with their own oil make-up sub pumps that provide pressure oil to the oil inlet of the hydraulic pump. The self priming hydraulic pump has a strong self priming ability and does not require external oil supply. After starting the machine each time, the hydraulic oil tank with pneumatic oil supply must wait until the hydraulic oil tank reaches the operating pressure before operating the machine. If the hydraulic oil tank is operated as a machine when the air pressure is insufficient, it will cause pulling off of the sliding whip in the hydraulic pump, resulting in abnormal wear of the return plate and pressure plate in the pump body. For a plunger pump that uses a makeup pump to supply oil, after 3000 hours of operation, the operator needs to inspect the plunger pump 1-2 times a day to check whether the hydraulic pump operates with a normal sound. If it is found that the speed of the hydraulic cylinder decreases or the vehicle is stuck, the make-up oil pump should be disassembled and inspected to check whether there are scratches on the edge of the impeller and whether the clearance of the internal gear pump is too large.
