Bearing system is an important part of the motor, is a key component of the mechanical properties of the motor embodied in the key components, to rationally configure the motor bearing system, first of all should understand the following issues.
1、Front bearing and rear bearing of the motor
The front bearing of the motor refers to the bearing close to the mechanical load side, also called load side bearing or axial end bearing; the rear bearing refers to the bearing close to the cooling fan side, also called fan side bearing or non-axial end bearing.
2、Locating end and free end of motor
Locating end and free end are a specific statement for the structure of motor bearing system. During the operation of the motor, due to various factors such as thermal expansion and contraction of the components, magnetic tension between the stator and rotor, etc., a certain range of axial movement will occur between the stator and rotor. In order to meet the axial dimensional changes and displacement problems that occur in the components, a certain amount of axial space must be left in the design and manufacturing of the motor. For this reason, when configuring the bearing system of the motor, the outer ring of the bearing will be fixed tightly at one end, i.e., the axial displacement of the bearing at this end will not be allowed to occur, and this end will be called the locating end or the fixed end; and the bearing system at the other end of the motor will leave a certain amount of axial clearance to fit with the outer ring of the bearing through the axial fit dimensions of the inner and outer bearing caps and the end cap, in order to ensure that the rotor part has the required axial displacement in the process of motor operation, since The end has axial mobility, so the end is called free end or floating end.
3、Deep groove ball bearings and cylindrical roller bearings
Deep groove ball bearings can limit the two-way movement of the shaft, high precision, low coefficient of friction, is the ideal choice for motor positioning end, the ball and the bearing sleeve for line contact, that is, the bearing running process of the contact trajectory for the circular line ring, the contact surface is relatively small, the radial load bearing capacity is not big, not suitable for withstand impact loads and heavy loads; and cylindrical roller bearings have no axial restriction of the rollers, do the free end of the support to be used, can Adapt to thermal expansion or installation error caused by the shaft and shell relative position change, roller and raceway is line contact, bearing running track is a circular ring, contact surface is larger, radial load carrying capacity, suitable for bearing heavy load and shock load.
4, motor bearing positioning end selection
From the actual operation of the motor and to meet the matching equipment with the docking compliance considerations, the positioning end of the general selection in the axial end, and for the axial relative position requirements are not strict conditions, can also be selected in the non-axial end, tend to motor load requirements can be; but if the towed equipment on the motor axial runout has more stringent requirements, then the motor bearing positioning end must be selected in the axial end. Positioning end bearing outer ring by the inner and outer bearing cover stop dead, bearing cover fastened to the bearing sleeve or end cover.
5、Selection of motor bearing type
When the load carried by the motor is not large, deep groove ball bearings are generally used; and in accordance with the requirements of the actual working conditions, for shock loads, as well as larger loads, cylindrical roller bearings should be used in the axial end of the motor, compared with the same size of the deep groove ball bearings, cylindrical roller bearings radial bearing capacity can be increased by 1.5-3 times, rigidity and shock resistance is better. Deep groove ball bearings bearing radial force than cylindrical roller bearings weak, but can carry a certain amount of axial force, while cylindrical roller bearings can not carry axial force. In view of the deep groove ball bearings and cylindrical roller bearings structural characteristics, for the need to configure cylindrical roller bearings for the motor, should be configured using a mixed mode, that is, there must be at least one set of deep groove ball bearings with its use.
The power of high voltage motors is often large, in order to meet the heavy load and small axial runout control, usually in accordance with the standard configuration of the three-bearing structure. In order to improve the bearing capacity and service life of the axial extension end bearing, in the axial extension end with a set of cylindrical roller bearings and a set of deep groove ball bearings side by side, cylindrical roller bearings to bear radial loads, and deep groove ball bearings for the locating bearing axis, only to bear the axial loads (and thus the deep groove ball bearing outer ring and bearing sleeve radial usually leave a certain clearance); the other end of the motor according to the actual need to select the deep groove ball bearings, if necessary, you can also The other end of the motor can choose deep groove ball bearings according to the actual needs, and cylindrical roller bearings can also be chosen if necessary.
In order to prevent the bearings from running in the motor operation, the bearing outer ring and bearing room, bearing inner ring and shaft must choose the appropriate fit tolerance; Whether it is the axial end of the bearing device, or non-axial end of the bearing device, are labyrinthine structure, and sealing with sealing ring, not only to prevent the bearing room of the lubricating grease leakage to the inside of the motor, damage to the coil insulation, but also prevent the outside of the dust or water into the bearing room, to keep the bearings clean. It also prevents outside dust or water from entering the bearing chamber and keeps the bearings clean.
The high voltage motor bearing system should be equipped with grease filling and draining pipes to facilitate the replacement of grease, and can realize non-stop refueling or draining.
Post time: Jul-19-2024
