The impact of bearing clearance on bearings

The impact of TIMKEN bearing clearance on bearings


The clearance of a rolling bearing refers to the distance that the inner and outer rings of the bearing can move under no load, that is, when the bearing is not assembled on the shaft or the bearing box, the inner ring or the outer ring is fixed, and then the The amount of movement when the fixed side moves radially or axially. According to its moving direction, the radial movement is called the radial clearance, and the axial movement is the axial clearance.

1. The radial clearance of the bearing will change correspondingly under different conditions, so it can be divided into original clearance, assembly clearance and working clearance:

(1) The original clearance refers to the clearance in a free state after the complete set of the bearing is assembled in the machine and equipment. It is determined by the processing and assembly of the manufacturer.

(2) The assembly clearance is also called the fit clearance, which is the clearance when the bearing, the shaft and the bearing seat are assembled but not yet working. Mainly because of the interference assembly, or the inner ring is enlarged, or the outer ring is reduced, or both, all make the assembly clearance smaller than the original clearance.

(3) The working clearance is also called the effective clearance, which refers to the actual clearance existing in the bearing under the condition that the bearing is assembled in the main engine and realizes the stable operation of the corresponding temperature rise under the corresponding load function. The working clearance is smaller than the original clearance, but compared with the assembly clearance, it is mainly because the temperature rise of the inner ring increases and the thermal expansion increases during operation, which reduces the bearing clearance. At the same time, it is mainly because of the effect of the load. The elastic deformation caused by the contact between the rolling element and the raceway causes the bearing clearance to increase. Whether the actual clearance is larger or smaller than the assembly clearance depends on the combined effect of these two factors. 662.When the bearing clearance is too small, the bearing temperature is more likely to be too high. If the speed is faster, it may cause burnout. If it is operated in a high temperature and high speed environment for a long time, the bearing may be locked and cause damage to the supporting shaft of the bearing or the bearing position of the housing. When the bearing clearance is too large, the rotor will move during operation. Therefore, the size of the bearing clearance can directly interfere with the performance of the bearing's running accuracy, rotation flexibility, vibration, and noise. The clearance that does not meet the standard will cause the bearing to fail in the initial stage. Therefore, for the bearing used in vacuum transmission, the change of the clearance caused by the change of temperature and other reasons must be considered in the whole process and the transfer in the solid lubrication bearing. Changes in clearance caused by membranes and trace wear debris. 

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