As the maintenance knowledge of gear pumps increases with the use of time, gear pumps will show problems such as lack of pump oil or even no oil. The primary cause is excessive wear of the relevant parts. The wear parts of the gear pump mainly include the automatic shaft and bushing, the intermediate hole of the driven gear and the shaft pin, the inner cavity of the pump casing and the gear, the end face of the gear and the pump cover, etc. When the primary technical target of the smooth oil pump fails to meet the requirements after wear, it should be disassembled and divided, the worn parts and level should be checked, and the response method should be used to repair it.
1. Repair of automatic shaft and bushing after wear. After the automatic shaft and bushing of gear pump are worn, the common clearance increases, which will definitely affect the oil volume of the pump. The normal common clearance can be restored by repairing the automatic shaft or bushing. If the automatic shaft is slightly worn, just press out the old bush and replace it with a bush of standard size, and the common clearance can be restored to the agreed limit. If the automatic shaft and the bushing are severely worn and the common gap is severely exceeded, not only need to change the bushing, but also use chrome plating or vibration surfacing to increase the diameter of the automatic shaft, and then grind to the standard size to restore the bushing Common requirements.
2. Repair of smooth oil pump shell. Repair of shell cracks: shell cracks can be repaired by welding with cast 508 nickel copper electrodes. The welding seam must be tight and porous, and the flatness error of the connecting surface of the pump cover shall not exceed 0.05 mm. Repair of automatic shaft bushing hole and driven shaft hole wear: After the automatic shaft bushing hole is worn, reaming can be used to eliminate the wear and tear, and then a bushing enlarged to a response size can be used. The wear of the driven shaft hole is also eliminated by reaming, and then according to the actual size of the reamed hole, the repair of the inner cavity of the driven shaft pump casing is prepared: After the inner cavity of the pump casing is worn, the inner cavity inserting method is generally used to repair. The stand-alone dust collector will be equipped with cast iron or steel bushings after lining the inner cavity. After inserting the sleeve, line the inner cavity to the required size, and grind off the bushing that protrudes from the end face to make it flush with the connecting surface of the pump casing. Repair of valve seat: There are two types of pressure limiting valves: spherical valve and plunger valve. After the spherical valve seat is worn, a steel ball can be placed on the valve seat, and then the steel ball can be knocked quietly with a metal rod until the ball valve and the valve seat are tightly sealed. If the valve seat is severely worn, it can be reamed to remove the wear marks, and then use the upper method to make it tight. After the plunger valve seat is worn, a little valve sand can be put in for grinding until it is tightly sealed.
3. Repair of the pump cover. Repair of the task plane: If the task plane of the pump cover is less worn, manual grinding can be used to eliminate the wear and tear, that is, put a little valve sand on the platform or thick glass plate, and then place the pump cover on it for grinding , Until the wear and tear disappeared and the task looks flat. When the task plane wear depth of the pump cover exceeds 0.1 mm, it should be repaired by turning first and then grinding. Repair of the automatic shaft bushing hole of the dust collector bag cage: The repair of the automatic shaft bushing hole wear on the pump cover is the same as the repair method of the automatic shaft bushing hole wear of the casing. Fourth, the use of gear flipping Gear pump gear wear is mainly in the thick part of the tooth, and the wear of the gear end face and tooth top is relatively light. The gear is worn on one side at the tooth thickness, so the gear can be turned 180 degrees for use. When the end face of the gear is worn, the end face can be ground flat, and the connecting surface of the smooth oil pump casing can also be ground to ensure that the gap between the end face of the gear and the pump cover is within the specification limits.
