Notes on detailed configuration of motor bearings

The detailed configuration of motor bearings not only involves the motor bearings themselves, but also other related accessories, such as shafts and bearing seats, which are all key components of the motor's bearing system. In addition, lubricants and hydraulic seals are also very important components. To fully utilize the characteristics required for a bearing in all aspects, it is necessary to apply suitable lubricants and a reasonable sealing system software to prevent air pollutants from entering the bearing. After many years of certification, cleanliness poses a significant threat to the service life of bearings, which is the key reason why standard bearing manufacturers extended their business scope to lubrication and sealing products many years ago. Today, Ms. Zhang will briefly discuss with everyone the difficulties that should be concerned about bearing equipment.

Difficulties to be Concerned about in Bearing Equipment

To design an ideal bearing configuration, the following things must be done, perhaps the same applies to the motor bearing configuration.

Select the appropriate type of bearing.

● Clearly determine the appropriate bearing size.

● Construction and design plans for other components in the equipment.

Moderate tolerance fit and bearing clearance or torque.

The method of fixing fixed bearings.

Moderate sealing system software.

The type and amount of lubricant used.

Installation and disassembly methods, etc.

Each item on the left and right is detrimental to the characteristics, reliability, and cost-effectiveness of all bearing equipment. The time and labor involved in selecting bearings depends on whether the customer has similar work experience in bearing equipment. If there is a lack of work experience, unique regulations in application, or detailed consideration of the cost of bearing equipment and other related factors, it is necessary to do more detailed work in motor selection, including more accurate calculations or inspections.

When selecting the specifications of bearings, it is possible to determine the required bearings based on the load on the bearings and the regulations on their service life and reliability during operation, and the rated load of the bearings. The product table lists the basic rated dynamic load C and the basic rated static load Co.

The standards for static and dynamic loads of bearings must be calculated separately. When checking dynamic loads, the most practical load spectrum should be used for column calculation, including the larger loads that will occur. Static load not only refers to the load that needs to be applied to the bearing when it is stationary or at a very low speed ratio (n>10r/min), but also needs to be checked for static load safety performance under heavy impact loads (loads with short-term effectiveness).

The System Software Method for Selecting Bearings and the Reliability of Bearings

The ground stress commonly considered in the service life relationship of bearing ratings includes: ground stress caused by external forces, and ground stress caused by surface conditions, lubrication conditions, and flipped surfaces in kinematics. Based on fully considering the harm of this kind of stress on the service life of bearings, more accurate prediction and analysis of the characteristics and main performance of bearings can be made in special applications.

Under normal circumstances, metal fatigue on the flipped surface is the key reason for the failure of roller bearings. Therefore, for a specific application, suitable roller bearings and specifications have been selected based on the fatigue of the dovetail guide rail. The national standard IS0281 is based on the metal fatigue of flipped surfaces. But more importantly, the complete set of bearings should be regarded as a system software, in which the components that will be stored, namely the cage, lubricant, and its hydraulic seals, have the same effect on the durability of the bearings during their service life, and in some cases, also play a core role. In basic theory, when all components exceed the same service life, it is considered the most ideal working life.

In other words, if the specific service life of a bearing exceeds the calculated service life, the service life of its components during operation must also at least exceed the calculated service life of the bearing. Important components include retainers, hydraulic seals, and their lubricants. In practical applications, metal fatigue is still the most critical factor.