shaft bending and cover bolts clamping surface is not perpendicular to the axis of the bolt

 poor lubrication: The reason is a serious lack of grease or oil dry aging. As the motor at high speed friction and heat, resulting in high bearing temperatures and oxidation discoloration, manifested as ball bearings, cage, inner ring and its journal, etc. zys precision bearing brown or blue.
Prevention Methods: According to the motor running time, ambient temperature, load conditions, such as grease or bad four factors that determine its complement oil and oil change time. Under normal circumstances, the motor should run 6000 ~ 10000h fill oil 1; run 10000 ~ 20000h should oil 1, 2 or 4-pole motor oil change over the bearing chamber volume of 1/2 to 2/3, and should be of high quality lithium grease (Code ZL-2).
3 installation did not pair: If the installation is not right, you not only have beads bearing slide marks, but the ball uneven wear marks, but also produce skewed, with a feeler bearing radial clearance on both sides will vary, and quite different. May be due to a direct hit with an iron hammer over bearing outer ring; belt pull (gear meshing) too tight; make the drive pulley and the driven pulley is not parallel to the centerline. When it is skewed more than 1/1000, it will cause the bearing operating temperature is too high, slide and ball severely worn, shaft bending and cover bolts clamping surface is not perpendicular to the axis of the bolt.
Proper installation: smooth end face, and almost equal to the thickness of the bearing steel inner sleeve, the pressure in the bearing journal clean the correct position. Press-fitting force should be uniform, not too much. Then check the motor shaft radial different speeds allow deflection values.
4 strong vibrations: When the motor core is faulty, the cause bearing strong vibration. Reasons are: core thermal deformation; motor bearings aging; shaft bending deformation greater; cover only the mouth tighten the bolts loosening due to vibration; foundation is not solid so that the bearing vibration.
Prevention Methods: core small car, soaked with silicon organic silicon surface and the varnish 1052 opened the gap; replace the same model new bearings; exit rotor core shaft straightening the bent portion; using 180 ° symmetry method; tighten the end cap of the Mouth Bolt; reinforcement base, tighten the anchor bolts.
5 Fatigue: As the metal material fatigue, and ball bearing raceway surface fractal shedding if mixed in grease will make it work noise increases, the ball was sliding state, causing the bearing radial clearance increased, and permissible radial shaft deflection value increases 2 to 3 times. Bearing fatigue determinants include: the motor load, speed, the air gap, cover type, the toughness, the amount of the grease mass retrofitting grease.
Prevention Methods: According to the motor running records, when the light-load operating current rating of 60% or more, run to the 2000 ~ 25000h, medium load operating current rating of 60% to 80% of the run to the 15000 ~ 20000h, heavy-duty operating current is rated 80% to 100% to 10000 ~ 15000h run after bearing material should be considered a normal fatigue, the replacement of the same model with new bearings.