What are the factors that affect bearing selection?

What is bearing selection?

The type and size of the bearing is selected based on the required rated life, space and lubrication conditions, and of course also includes recommendations for installation and removal. Selection can be simple and can be completed quickly by experienced sales staff based on bearing catalogs.

What are the factors that affect bearing selection?

1. Number of bearings

The number and cost have a direct impact. If bearings are used in large quantities, the number of bearings required or the information on annual bearing consumption will be very important. Try to choose conventional, standard, and suitable bearings for large-scale use.

2. Drawing information

Detailed drawings containing bearing dimensions, tolerances, and bearing arrangements are important sources of information, as well as drive equipment and drive connections. Through the drawings, bearing technicians can see things that customers think are unimportant.

3. Load information

The information provided should be sufficient so that the bearing application engineer can well understand the changes in the load direction.

A common mistake is to only give the maximum load, thinking that if the bearing can withstand the highest load, it must be able to withstand lower loads. This is not absolute, and under certain conditions, the rolling elements may slide instead of rolling. Therefore, the maximum and minimum loads should always be given.

4. Impact information

Impact is also a load, usually high but short-lived. It needs to be compared with the static load capacity of the bearing. Impact will cause the rolling elements to impact the bearing cage, so repeated impact loads will affect the choice of cage.

5. Vibration information

Vibration can have an impact on the bearing, especially when stationary. This is because of the risk of false brinelling failure (fretting wear caused by rolling elements vibrating in the same position). Vibration can also affect the lubricant. For example: under vibration, grease may lose consistency and move away from the bearing.

6. Acceleration information

Bearing selection requires consideration of more than just rotational acceleration, which can cause rolling elements to slide rather than roll. It is also necessary to consider centrifugal acceleration, where bearing components rotate around an axis, such as a vibrating screen or planetary gearbox, which can affect the choice of bearing cage.

7. Speed information

Speed and load are key parameters, so a speed graph or histogram is very useful information. Knowing only the maximum speed can lead to lubrication problems. For example, a lubricant selected based only on the maximum speed may not establish an adequate oil film at lower speeds. Long stationary times should also be noted, and bearings may fail due to pseudo-brinelling due to vibration or stationary corrosion from adjacent equipment.

8. Rated life requirements

Speed and load are key parameters, so a speed curve or histogram is very useful information. Knowing only the maximum speed can lead to lubrication problems. For example, a lubricant selected based only on the maximum speed may not establish an adequate oil film at lower speeds. Long stationary times should also be noted, and the bearing may fail due to pseudo-brinelling due to vibration or stationary corrosion from adjacent equipment.

9. Available Space

Providing the available space dimensions at the beginning of the selection will allow us to select the appropriate bearing faster. Preliminary pre-selection of bearings is based on the available space and existing shafts.

10. Running accuracy

Standard running accuracy bearings are suitable for most applications. However, some precision-running equipment or high-speed equipment may require higher running accuracy.

Note: Overestimating and increasing the need for running accuracy will pay a higher cost.

11. Maximum deformation

Equipment components deform under load, so the technology is likely to require a maximum deformation.

One way to increase stiffness is to preload the bearing. In most cases, a slight bearing preload will theoretically increase bearing life, but increasing the preload may also cause uncontrolled operation.

12. Friction library requirements

Some applications may have special requirements for rotational friction torque.

13. Lubrication method and lubricant

Sometimes the equipment requires a special lubrication method, or a special lubricant. For example, a gearbox requires a high viscosity gear oil. With the preferred lubrication method and lubricant information, the application engineer can evaluate the operating conditions and whether the bearing is compatible.

14. Temperature

Ambient and operating temperatures affect bearing selection. It is very important to provide true maximum and minimum temperatures. If only the maximum temperature of the equipment is given, it may cause problems.

Note: Also do not overestimate the temperature of the equipment, as overestimation may lead to the selection of more expensive bearings instead of standard bearings.

15. Possible contamination

Provide information on possible contamination from the environment or equipment that may affect the selection of bearings, seals and lubrication.

16. Installation and removal requirements

Sometimes the space for installing and removing bearings may be limited. Therefore it is best to let the technician know about the restrictions that may affect the installation/removal of the bearing.

Please do not hesitate to contact us with any requirements.