Asynchronous motor bearing too tight or too loose? - bearing knowledge

If the bearing and shaft or cooperate with tight cover and sleeve bearing diameter ( Small tolerance) , strongly pressed when installation or install the bearing cover partial, will make bearing by external effect, the bearing due to the tight fever, affect the normal operation of the motor. Once found bearing too close, according to the tolerance size of sand grinding shaft or the shaft on a cylindrical grinding machine for processing. If too tight, due to improper assembly should be repackaging; If it is due to the lubricating oil viscosity is too high, caused jamming is a lubricating oil should be replaced. In the operation of the motor, due to the vibration of the mechanical part, and motor overhaul of disassembly and assembly for many times, bearing the easiest lax, generally has the following three types of exceptions: ( 1) Ball bearings have been broken. ( 2) Loose bearing inner ring with shaft, appear within the rims of relative movement and the rotation phenomenon, commonly known as 'set'. ( 3) Bearing outer ring with end cover is not tight, appear outside rims relative to the bearing seat and the movement of the phenomenon, commonly known as 'coat'. Due to the above failure, bearing position is not fixed, caused by the friction of the stator and rotor, make motor local overheating, serious when motor can not run normally. Usually take the following two ways to check: ( 1) Remove the bearing, wipe the grease inside the bearing, the bearing with gasoline wash, and then outer ring relative to the ball back and forth with the hand shaking. Good bearing and its clearance just perceptible. If the clearance between the inner ring and outer ring is very big, the bearing has been damaged. ( 2) Hand motor shaft, tilt up and down hard, to ascertain whether or not bearing looseness. If set, contact friction between the rotor and loose more than the normal clearance, the rotor iron core, then uranium bearing damage, cannot use. Treatment principle is: every bearing damage, ball ball bracket broken or damaged, must be put on the new bearing; When running set of light, but the axis on the lathe, the surface of shaft with a knurled knife in rolling pattern, but this is emergency measures, the better way is to set ring, ring and the shaft with a static coordination, the use of the place in combination with surface bolted. The best way is in the part of the shaft and bearing contact spraying a layer of metal material ( Such as nickel) , this kind of treatment, the use of the bearing for a long time.