Fixed End Bearings for Motors Fixed end bearings use radial bearings that can carry combined (radial and axial) loads. These bearings include: deep groove ball bearings, double row or paired single row angular contact ball bearings, self-aligning ball bearings, spherical roller bearings, tapered roller bearings in matched groups, cylindrical roller bearings of type NUP or cylindrical roller bearings of type NJ with HJ angular rings. For the selection of motor bearing support fixed end (referred to as motor fixed end), the following factors should be considered. (1) the precision control requirements of the equipment being towed. (2) the nature of the motor dragging load. (3) bearing or bearing combination must be able to withstand a certain axial force. Combining the above three design elements, in small and medium-sized motors, deep groove ball bearings are more often used as the first choice for motor fixed end bearings. Deep groove ball bearings are the most commonly used rolling bearings. When applying deep groove ball bearings, the structure of motor bearing support system is very simple, and the maintenance is easy. Deep groove ball bearings are mainly used to bear radial load, but when increasing the radial clearance of the bearing, with the characteristics of angular contact ball bearings, can withstand the combined radial and axial load; higher speed and should not use thrust ball bearings, can also be used to withstand pure axial load. With deep groove ball bearing specifications of the same size of other types of bearings, such bearings have the advantage of small coefficient of friction, high limit speed, the disadvantage of shock resistance, not suitable for heavy loads. Deep groove ball bearing installed in the shaft, in the bearing axial clearance range, can limit the shaft or shell two directions of radial fit. In the radial direction, bearing and shaft with interference fit, bearing and end cover bearing room or shell with a small interference fit, the ultimate goal of the choice of this fit is to ensure that in the motor running process, bearing clearance is zero or slightly negative, so that the bearing performance is better. In the axial direction, the axial fit of the locating bearing and the associated parts should be determined in conjunction with the specific conditions of the floating end bearing system. The inner ring of the bearing is limited by the bearing position limit step (shoulder) on the shaft and the bearing retaining ring, while the outer ring of the bearing is controlled by the fit tolerance between the bearing and the bearing chamber, the height of the inner and outer bearing cover stop and the length of the bearing chamber. Motor floating end bearing The floating end of the motor, also called the free end, is relative to the fixed end; in general, the floating end is selected at the non-driving end, but in the case where the motor load requirements are high and the axial fit dimensions with the load equipment are not very high, the floating end will be selected at the driving end. When the motor bearing support system is double pivot point and double bearing structure, the driving end is also used as the floating end when the radial load requirement is large, especially for low voltage high power and high voltage motors, the cylindrical roller bearing at the floating end can meet the requirement of larger radial load. Cylindrical roller bearing roller and raceway for line contact or repair under the line contact, radial bearing capacity, more suitable for bearing heavy load and shock load, inner ring or outer ring can be separated, easy to install and disassemble. The series bearing friction coefficient is small, suitable for high speed, limit speed close to the operating conditions of deep groove ball bearings. N type and NU type cylindrical roller bearings are more commonly used in electric motors, the inner and outer rings of the bearings can be moved axially, which can adapt to the change of relative position of the shaft and shell caused by thermal expansion or installation error, and can be used as free end support. However, the bearing has high processing requirements for the shaft or bearing chamber hole, and the relative deflection of the inner and outer ring axes after bearing installation should be strictly controlled to avoid contact stress concentration. Relative to the fixed end bearing, in order to meet the axial displacement requirements of the rotor part during the operation of the motor, the axial clearance requirements of the bearing outer ring and the bearing inner and outer cover are different according to the different bearing choices. (1) When the floating end uses the inner and outer ring separable bearings, for the two-bearing structure motor, the fixed end is selected at the non-driving end; the outer ring of the fixed end and floating end bearing and the bearing inner and outer cover are used axial clearance-free fit. (2) when the floating end of the non-separable bearing, that is, small and medium-sized motors are more common for both ends of the ball bearing structure, in view of the impact on the installation accuracy of the dragging equipment, using the drive end for the fixed end, the floating end of the bearing inner ring should be limited, the outer ring and bearing between the inner and outer cover stop axial clearance; at the same time, in order to ensure that the motor operation of the axial fit displacement requirements, the bearing outer ring and bearing chamber radial fit Not easy to be too tight. The actual bearing configuration should be matched with the operating conditions of the motor, including the motor bearing selection for clearance, heat resistance, precision and other specific parameters, as well as the radial fit relationship between the bearing and the bearing chamber.  

We have rich experience on precision bearing manufacturing and are ranked NO.1 in China and NO.3 all over the world.

We can tailor the overall solution for the use of precision bearings.

HONB– Accountability & Innovation