Motor Bearings

Motor bearings are special bearing used for electric motors. Generally the motor bearing is a part to support shaft, it is able to guide the rotation of the shaft and also bear the shaft idling. The normally used type of motor bearings are rolling bearings, sliding bearings, spherical plain bearings, oil-retaining bearing. Among them, the most common motor bearing is rolling bearing, that is the bearing equipped with a rolling element. Sliding bearings are bearings without rolling elements, but is able to do sliding movement. Motor bearings use the very smooth mental balls or rollers, as well as lubricated inner and outer rings and metal surface to reduce friction. The balls and rollers in motor bearings to carry the loadings, support the motor spindle, so the motor bearings can be stable rotation.

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Basic knowledge of motor bearings

In the power-requiring machinery and equipment, the motor as the main power source to complete and ensure the normal operation of the unit, so when the motor failure caused by the loss is considerable, especially medium sized motor, can seriously affect the unit safe operation.

According to the statistics of motor faults, it is found that motor bearing damage or motor damage due to bearing damage accounts for more than 60% of all motor faults, so solving motor bearing damage is also an important issue for solving motor faults. According to the analysis, medium-sized motors are mostly "end cap sliding motor bearing type" structure and "end cap rolling bearing type" structure.

After a variety of medium sized motor maintenance experience summary and analysis, there are the following questions:

1, the end cover sliding bearing motor type: Most of the existence of such motor bearing bush heat and oil spill phenomenon, resulting in the corrosion of the stator coil of the motor, and make the motor oil and too much fouling, resulting in poor ventilation, so that Motor temperature is too high and damaged.

2, box type high voltage motor: The motor is a new type of motor produced in China in recent years, its performance, shape are superior to the "JS Series" motor. However, some motors of this kind produced by the manufacturer have some problems in the design of the bearings, resulting in more motor faults in running motor bearings.

The structure of these motors is equipped with a small oil pan at the motor bearing outer side of the motor bearing gap, so that the grease inside the motor bearing to maintain adequate, but this structure has the following disadvantages: not conducive to heat and lubrication the cycle, motor bearing high temperature during operation.

Due to the presence of gear oil, small repair can’t open the bearing cover, overhaul can’t be cleaned to check, can only be replaced.

3, two bearings motor: Some medium-sized motors produced in our country now have double-bearing structure on the load side. Although this increases the radial load capacity on the load side, it also makes maintenance more difficult.

In the motor overhaul, the motor bearings can’t be cleaned and inspected and must be replaced, or can’t guarantee the quality of overhaul, resulting in increased maintenance costs. In addition, this structure of the motor, most of the bearings in the running temperature is relatively high, so that the motor bearing life is reduced and damaged.

4, motor bearing accessories structural problems: At present, most of our motor bearings are used inside and outside the oil cap structure.

The disadvantage of this structure is the sealing effect is poor, the motor inside and outside the dust easily sucked into the interior of the motor bearing to accelerate the wear and tear damage to the bearing; and then the structure of the motor bearing attachment to the motor bearing cooling, cooling and grease circulation basic Ineffective, so the motor bearing operating temperature is higher, lower life expectancy, resulting in less than one motor repair cycle bearing damage.

According to the analysis of imports of medium sized motor structure found, first, both sides of the motor bearing are all installed with a sealing device to ensure that the internal motor bearing clean; second motor bearing in the outer side with positioning, cooling device, and the motor bearing oil room space, This greatly reduces the temperature of the motor bearing operation, and get good lubrication, extending the service life of motor bearings.

5, the motor bearing selection problem: According to the analysis and calculation of the motor bearings that the bearing failure and bearing the choice has a great relationship.

From our motor and imported motor comparison, the load side of the domestic medium-sized motor bearings, the general is the choice of "medium sized roller bearings."

The radial bearing capacity of the bearing is greatly exceeded the calculated value, but the speed is allowed and the actual speed of the motor difference is very small, resulting in bearings not up to the rated life.

However, the import of medium sized motor load side of the motor bearing is generally larger "light ball motor bearings", while the load side is the use of smaller than the load side of the "light roller motor bearings", which not only ensures the motor bearing capacity, and motor bearing The allowable speed greatly exceeds the actual speed of the motor, so it can meet or exceed the service life of the bearing.

Motor Bearing Application Features:

Motor bearings are generally radial ball bearings, with seals or dust cover, radial ball bearings used up to large motor is short cylindrical roller bearings,

In some cases, the use of spherical roller bearings or tapered roller bearings, high-frequency motors use radial ball bearings.

Bottom noise bearings are the common requirements of a variety of motor bearings, especially household appliances motors, standard motors and small motors on the bearing noise requirements more stringent.

Noise in the operation of the bearing quality, improper use also have an impact. For example, machining in the dust and bearing housing cuts into the bearing with the rolling surfaces on installation

Creates indentations, bearing clearance is too large or clearance is negative, and poor lubrication, etc., will increase the bearing noise.

Motor bearings generally use grease. For sealed bearings, grease can often determine the life of motor bearings.