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Root causes and solutions for high temperature of motor bearings

wallpapers Tech 2020-12-16

Bearings are an important part of the motor. The running speed of the bearing will directly affect the performance of the motor. If the running speed is too low, the motor will not be brought up. If the running speed is too high, it will cause the motor to burn out the machine at a high temperature. Tell everyone, generally speaking, bearing overheating means that the rolling temperature rise exceeds 55, and the sliding bearing temperature rises above 40.


The root cause and solution of the high temperature of motor bearing


1. The rolling bearing is installed incorrectly, and the fit tolerance is too tight or too loose.


The working performance of rolling bearings not only depends on the manufacturing accuracy of the bearing itself but also on the dimensional accuracy, geometric tolerances and surface roughness of the matching shaft and hole, as well as the selection of matching and correct installation. In general horizontal motors, the assembled rolling bearing only bears radial stress, but if the inner ring of the bearing and the shaft are too tight, or the outer ring of the bearing and the end cover are too tight, that is, when the positive interference is too large, the assembly The rear bearing clearance is too small, sometimes even close to zero.


In this way, the rotation is not flexible, and heat will be generated during operation. If the inner ring of the bearing is too loose with the shaft, or the outer ring of the bearing and the end cover are too loose, the inner ring of the bearing and the shaft or the outer ring of the bearing and the end cover rotate relative to each other, causing the bearing to generate heat and overheat due to friction. In general, the tolerance zone of the inner diameter of the bearing inner ring as a reference part moves below the zero lines in the standard.


2. Improper selection or maintenance of lubricating grease, poor quality or deterioration of lubricating grease, or mixed with dust and impurities will cause bearing heating.


Too much or too little grease will also cause the bearing to heat up because too much grease will cause greater friction between the rotating part of the bearing and the grease, while too little grease will cause dry friction and heat generation.


Therefore, the amount of grease must be adjusted to approximately 1/2-2/3 of the volume of the bearing chamber. Unsuitable or deteriorated grease should be cleaned and replaced with suitable and clean grease.


3. The axial gap between the outer bearing cap of the motor and the outer circle of the rolling bearing is too small.


Large and medium-sized motors generally use ball bearings at the non-shaft extension end. The shaft extension end adopts roller bearings so that the rotor can extend freely when it is heated and expanded. Since ball bearings are used at both ends of a small motor, there should be a proper clearance between the bearing outer cover and the bearing outer ring, otherwise, the bearing may be heated due to excessive axial thermal extension.


When this phenomenon occurs, the front and rear bearing covers should be removed, or a thin paper pad should be added between the bearing cover and the end cover so that a sufficient gap is formed between the outer bearing cover and the outer ring of the bearing.


Wuxi Spark Bearing Co., Ltd is a complete, one-stop bearing supplier and manufacturer. All bearings products are qualified and have passed the ISO 9001 certification. We have more than 12 years of experience in bearings, please contact us if necessary, we will reply to you as soon as possible.