The most common type of bearing used in electric motors is the deep groove ball bearing. In the field of industrial motors, the use of deep groove ball bearings accounts for more than 70% of the total use of bearings. In terms of the quantity used, the proportion will be even greater. Therefore, if electrical engineers can be very familiar with deep groove ball bearings, they can understand the application of motor bearings to a large extent.

Deep groove ball bearings, the previous domestic standard is called radial ball bearings. As the name implies, this type of bearing is a type of rolling bearing that bears a centripetal load and the rolling elements are spherical. The centripetal load mentioned here is the so-called radial load. Therefore, the main load bearing capacity of deep groove ball bearings is in the radial direction.

At the same time, due to the structural characteristics of its groove, the bearing can bear a certain axial load. The axial load capacity of deep groove ball bearings is much weaker than the radial load capacity. Therefore, under the condition of axial load, it is necessary to check the life of the deep groove ball bearing to ensure that the bearing can achieve the expected effect of operation under this load.

The figure below shows a typical deep groove ball bearing.

Compared with roller bearings, deep groove ball bearings have point contact between the inner rolling body and the raceway. Below we briefly analyze the characteristics and limitations of deep groove ball bearings.

1. Characteristics of deep groove ball bearings

1. The ability to withstand radial load is weaker than that of roller bearings. The load capacity of deep groove ball bearings is smaller than that of corresponding roller bearings, but it is sufficient for general industrial motors. Often, for the working conditions of external pulleys and other additional radial loads, the load capacity may not meet the requirements, and cylindrical roller bearings can be used at this time.

2. The internal friction of the bearing is relatively small, and there is point contact between the small heating rolling elements and the raceway, and the internal heating of the bearing is relatively small. If it is a bearing with a seal, the frictional heating of the seal needs to be considered during operation.

3. The speed capacity of the bearing is high. The internal rolling body of the deep groove ball bearing is a ball. Compared with the roller bearing, the mass of the rolling body is relatively small, and the centrifugal force is small when rotating at high speed. Relatively good strength, so the mechanical limit speed capability of deep groove ball bearings is relatively high. Correspondingly, due to relatively less heat generation, the thermal reference speed capability of deep groove ball bearings is also relatively high.

4. Simple bearing arrangement Deep groove ball bearings can bear both axial load and radial load, so this kind of bearing can be used as locating end bearing or non-locating end bearing.

5. Easy to use, convenient storage and transportation Deep groove ball bearings are usually one-piece bearing structure, so the installation, storage and transportation of bearings are simpler than split bearings.

6. Simple maintenance Generally, deep groove ball bearings are open, with dust cover and with seals, which greatly simplifies the workload of bearing relubrication, and has the characteristics of simple operation.

Second, the limitations of deep groove ball bearings

Due to its structural characteristics, deep groove ball bearings also have their own limitations:

1) Anti-eccentricity

Ordinary deep groove ball bearings have very limited eccentric adjustment capabilities, generally within the range of less than 10 arc minutes. This eccentricity is brought by its own structure and clearance, not reserved for the application conditions. Therefore, it is not recommended for electrical engineers to use this eccentricity capability.

2) Damage during bearing installation

The interior of deep groove ball bearings is point contact, so it is very easy to be injured during installation. Therefore, when the motor bearing is installed, it is necessary to avoid the damage of the raceway caused by the installation force through the rolling elements.

3) Temperature limit

Generally, the heat treatment dimensional stability temperature of deep groove ball bearings without special instructions is 120 degrees Celsius. Therefore, deep groove ball bearings are not suitable for operation at temperatures higher than this.

At the same time, when selecting deep groove ball bearings for high temperature conditions, it is also necessary to consider the temperature limitations of lubricants, cages and seals. (Please refer to related articles in the official account)

4) Applications under vibration conditions

Deep groove ball bearings are prone to damage to raceways and rolling elements under vibration conditions, so deep groove bearings will encounter certain challenges under vibration conditions.

All in all, deep groove ball bearings are good motor bearings. Of course, there will be slight differences between brands. This article only shares the commonality of such bearings.

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