With the improvement of the repair knowledge of the gear pump and the use of time, the gear pump will show the problems of lack of pump oil or even no oil. The primary reason is that the relevant parts are worn too much. The wear parts of gear pump mainly include automatic shaft and bushing, intermediate hole and shaft pin of passive gear, inner cavity of pump housing and gear, gear end face and pump cover, etc. If the primary skill target of the smooth oil pump fails to meet the requirements after being worn, it shall be disassembled and differentiated to find out the worn part and level, and the response method shall be accepted for repair.
1、 Repair of worn automatic shaft and bushing after the wear of automatic shaft and bushing of gear pump, their common clearance will increase, which will 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 bushing and replace it with a bushing of standard size, and the common clearance can be restored to the allowable limit. If the automatic shaft and bushing are severely worn and the common clearance exceeds the standard, it is not only necessary to change the bushing, but also use chromium plating or vibration surfacing to increase the diameter of the automatic shaft, and then grind it to the specified size to restore the common requirements with the bushing.
2、 Repair of smooth oil pump shell and repair of shell crack: the shell crack can be repaired with cast 508 nickel copper welding rod. The weld must be tight and free of air holes, and the flatness error of the interface with the pump cover shall not be greater than 0.05mm. Repair of the wear of the automatic shaft bushing hole and the driven shaft hole: after the automatic shaft bushing hole is worn, the wear traces can be eliminated by reaming, and then the bushing increased to the response size can be used. The wear of the driven shaft hole is also eliminated by reaming, and then the repair of the inner cavity of the driven shaft pump shell is prepared according to the practical size of the reamed hole: after the inner cavity of the pump shell is worn, it is repaired by using the inner cavity inlay method, and the single machine dust collector is lined with a large inner cavity and then inlaid with cast iron or steel bushing. After the sleeve is inserted, the inner cavity shall be lined to the required size, and the bushing protruding from the end face shall be ground off to make it flush with the connecting surface of the pump housing. Repair of valve seat: there are two kinds of pressure limiting valves: ball valve and plunger valve. After the ball 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 closed. If the valve seat is severely worn, ream it first to remove the wear marks, and then use the above method to make it close. After the plunger valve seat is worn, a little valve sand can be put into it for grinding until it is tight.
3、 Repair of pump cover task plane: if the wear of pump cover task plane is small, manual grinding method can be used to eliminate the wear traces, that is, put a little valve sand on the platform or thick glass plate, and then put the pump cover on it for grinding until the wear traces are eliminated and the task surface is flat. When the wear depth of the pump cover task plane exceeds 0.1mm, it should be repaired by turning first and then grinding. Repair of the automatic shaft bushing hole of the bag cage of the dust collector: the repair of the worn automatic shaft bushing hole on the pump cover is the same as the repair of the worn automatic shaft bushing hole of the housing. 4、 The gear wear of gear pump is mainly at the tooth thickness, while the wear of 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 gear end face is worn, the end face can be ground flat and the connecting surface of the oil pump housing can be ground smooth to ensure that the clearance between the gear end face and the pump cover is within the specification.
