With the increase of the use time, the Rexroth gear pump will have insufficient pump oil or even oil pump failure, the main reason is that the relevant parts are excessively worn. The wear parts of Rexroth gear pumps mainly include drive shaft and bushing, passive gear center hole and shaft pin, pump casing inner cavity and gear, gear end face and pump cover. When the main technical indicators of the lubricating oil pump fail to meet the requirements, they should be disassembled and decomposed, the wear parts and extent should be ascertained, and corresponding measures should be taken to repair them.
1.Drive shaft and bushing wear repair
Rexroth gear pump drive shaft and bushing wear, its fit gap increases, will affect the pump oil.In this case, can be used to repair the drive shaft or bushing method to restore its normal fit gap.If the drive shaft wears slightly, just press out the old bushing and replace it with a standard size bushing, and the fit gap can be restored to the allowable range.If the drive shaft and bushing wear seriously and the fit gap is seriously exceeded, not only to replace the bushing, and the drive shaft is also used chrome plating or vibration surfacing method to increase its diameter, and then grinding to the standard size, and restore the matching requirements of the bushing.
Oil pump shell repair shell crack repair:
Shell cracks can be repaired by casting 508 nickel-copper welding rod.The weld shall be tight and air holes, and the flatness error of the joint surface with the pump cover shall not be greater than 0.5 mm.
Repair of active bushing hole and driven bushing hole wear: after active bushing hole wear, the wear marks can be eliminated by means of pin cutting, and then the bushing can be enlarged to the corresponding size.The hole wear of driven shaft was also eliminated by means of hinging, and then the driven shaft was prepared according to the actual size of the hinged hole.
Pump shell inner cavity repair: pump shell inner cavity wear, generally adopt the inner cavity set method repair, that is, after lining the inner cavity large set with cast iron or steel bushing.After inserting the sleeve, lining the inner cavity to the required size, and grinding the bushing extending out of the end face, so that it is flush with the combined surface of the pump shell..
Valve seat repair: pressure limit valve ball valve and plunger valve two kinds.When the ball seat is worn, place a steel ball on the seat and gently tap the ball with a metal bar until the ball valve is closed to the seat.If the valve seat is badly worn, it can be hinged to remove the wear marks and then used to close it.Plunger valve seat wear, can put a little valve sand to grind, until close.
3. Pump cover repair
Work surface repair: if the pump cover work surface wear is small, can use manual grinding method to eliminate wear traces, that is, put a little valve sand on the platform or thick glass plate, and then put the pump cover on the above for grinding, until the wear traces are eliminated, the work surface is smooth.When the pump cover working surface wear depth exceeds 0.1 mm, should take the method of grinding after turning repair.
Active shaft bushing hole repair: pump cover on the active shaft bushing hole wear repair and shell active shaft bushing hole wear repair method is the same.
4. Gear turnover use
Rexroth gear pump gear wear is mainly in the tooth thickness, and gear end face and tooth top wear are relatively light.The gear is worn on one side at the tooth thickness, so it can be used by turning the gear 180 degrees.When the end face of the gear is worn, the end face can be ground, and the lubricating oil pump shell bonding surface can be ground at the same time, so as to ensure that the clearance between the end face of the gear and the pump cover is within the standard range.