Bearing parts with improper bearing failure

(1) on August 3, 1998 alkylation J - 401355 - kw motor using the general clearance bearing in the process of maintenance, due to the bearing parts tolerance matching, large amount of interference caused by bearing clearance is too small, only 0.06 mm, cause machine commissioning, die bearing heating stick, bent rotor bearing parts, after spray welding processing repair, choose C3 series, large clearance bearing, clearance of 0.12 mm, after assembling the related bearing heat damage again, when the inspection found that the rotor axial cooperate there is a deviation, adjust the axial size close to 1 mm, and choose 0.15 mm clearance C3 series Supplier For Cheap FAG 6305, motor running after assembly.

(2) on August 22, 1998, the north side of coking in 6/175 B - kw motor fan bearing overheating is damaged, repair the bearing parts and diameter of axle shaft shoulder injury, the axial deviation is 0.8 mm, with spray welding processing, oil on the inside of the side cover with 1 mm thick asbestos gaskets, shaft extension end bearing running coat, in the operation of the heating, the end cover hole is the brush plating processing, the assembly after the motor running well.

Cause analysis,

(1) bearing inner and outer ring of tolerance matching, causing premature failure. General shaft and bearing inner ring USES the surplus to cooperate, H7 / m6 transgressions bearing outer ring and the hole using J7 / h6 transition fit. Cold, do not produce relative sliding bearing inner ring and the shaft, the interference if the amount is too large, running on the heating effect of the current in the rotor shaft and bearing heat expansion, damaged bearing reasonable work clearance, cause work clearance is too small, bearing heating failure. Also, the bearing outer ring would undermine its working with tight clearance. If bearing fitting surface wear and undermined its normal use level, cause work of bearings and cooperate with relative sliding surface, caused by friction heat, make the bearing failure.

(2) motor, the rotor is different, center with super poor. Due to machining error of the stator with end cover and the maintenance of the influence of such factors as worn, and the machining error of the end cover itself and wear and tear, make different heart motor bearing inner and outer ring, a tilt Angle a, tilt Angle of a super bad, will cause the roller or ball local squeeze, bearing clearance decreases, and bearing heating and premature failure. General single centripetal short cylindrical roller bearing allows tilt Angle as a '2 or less, single-row radial ball bearings for a = 2' ~ 10 ', maximum Angle does not allow more than 1/30 and 1/6 degrees respectively.

(3) the motor stator and rotor bearing axial position with super bad. Because each processing surface, the rotor axial positioning error accumulation, the axial to super bad, especially the position deviation on both sides of the bearing, bearing caused by axial plane displacement of inside and outside the circle of short cylindrical roller bearing, it can adjust the axial location, but for deep groove ball bearings, roller cannot in the original free rolling groove, steel ball is extruded, reduce work bearing clearance, affect the bearing life, even cause bearing failure quickly. When more than 500 mm distance between both ends of the rotor bearing, thermal expansion factor of rotor shaft, should also be considered generally in shaft extension end bearing between the lateral and outside the oil cap of 0.1 ~ 0.5 mm gap.

(4) the flameproof motor, the flame-proof curved eccentric shaft parts with the bad, such as vessel to cause such as mutual friction heat between the matching surface, make the bearing operating temperature is too high and lead to bearing failure.