How to choose motor bearings? PPH bearings teach you how to select motor bearings!

Motor bearings are a common application scenario in bearing selection. The requirements for bearing selection may vary depending on the structure of the motor. PPH Bearing specializes in various types of ball bearings with seats, motor bearings, agricultural machinery bearings, etc. Today, PPH Bearing will share with you how to choose motor bearings.

Selection and use of motor bearings:

1、 Selection of PPH bearings

1. The selection of bearing model: The bearing model is generally chosen by the user's technical personnel based on the usage conditions and load capacity of the supporting product. Business personnel mainly understand whether the actual load of the user is consistent with the selected bearing. If the bearing does not meet the usage requirements, they should advise the customer to change the model as soon as possible, but unless there are special products, there is generally no problem in selecting the model.

2. Selection of bearing clearance: When purchasing PPH bearings, users generally only inform them of the model and grade, and rarely make requirements for bearing clearance. Business personnel must inquire about the usage conditions of the bearings, including their speed, temperature, and fit tolerance, which directly affect the selection of bearing clearance. Generally, motors with speeds below 3500 revolutions per minute use CM clearance, while high-temperature and high-speed motors require relatively large clearance. The clearance of the bearing will decrease after assembly due to the enlargement of the inner hole and the reduction of the outer circle. The reduction in clearance is equal to the interference fit multiplied by 60% (except for bearing chambers made of aluminum). For example, if the clearance before bearing assembly is 0.01mm and the interference fit during assembly is 0.01mm, then the clearance after bearing assembly is 0.004mm. In theory, the noise and lifespan of bearings reach their optimal state at zero clearance, but in practical operation, considering issues such as temperature rise, it is better for the clearance of bearings to be 0.002mm-0.004mm after assembly.

3. Selection of grease: The selection of grease is generally based on factors such as bearing speed, temperature resistance, noise requirements, and starting torque. Business personnel are required to have a good understanding of the performance of various types of grease.

4. Selection of bearing sealing type: Lubrication of bearings can be divided into oil lubrication and grease lubrication. Oil lubricated bearings are generally selected as formal bearings, while grease lubricated bearings are generally sealed with dust covers or rubber seals. Dust covers are suitable for areas with high temperatures or good usage environments. There are two types of seals: contact seals and non-contact seals. Contact seals have good dust resistance but high starting torque, while non-contact seals have lower starting torque but lower sealing performance than contact seals.

2、 Precautions for using PPH bearings

1. Selection and control of shaft and bearing chamber tolerances: After the bearing is pressed into the bearing, it should rotate flexibly without any resistance. If there is obvious inflexibility in rotation, it indicates that the size of the shaft is too large and the tolerance needs to be lowered. If there is a noticeable "rustling" feeling when the shaft is pressed into the shaft and rotated by hand, it may be due to excessive tolerance or poor roundness of the shaft. So when controlling the tolerances of the shaft and bearing chamber, it is also necessary to control the roundness. Currently, many domestic manufacturers only control the tolerances and do not control the roundness. The quality inspection of PPH aviation bearings is comprehensive.

2. Assembly method of bearings: As bearings are high-precision products, improper assembly can easily cause damage to the bearing channels, leading to bearing damage. Bearings should have dedicated molds during assembly and should not be knocked randomly. When pressing the shaft, only small rings can be subjected to force, and when pressing large rings, only large rings can be subjected to force. During assembly, it is required to use air pressure or hydraulic pressure. The upper and lower molds should be in a horizontal state during press fitting. If there is any inclination, it will cause damage to the bearing groove due to force, resulting in bearing noise.

3. Prevention of foreign objects during assembly: When the bearing is installed on the rotor for dynamic balancing, it is easy for iron filings generated during dynamic balancing to enter the interior of the bearing. Therefore, it is best to perform dynamic balancing before installing the bearing. Some manufacturers apply some oil or grease to the bearing chamber for lubrication during assembly, in order to facilitate assembly. However, it is often difficult for operators to control the amount properly. If a large amount of oil or grease accumulates in the bearing chamber, it is easy for it to enter the bearing along the shaft during rotation. It is best not to apply oil or grease to the bearing chamber. If it is necessary to do so, it is necessary to control the accumulation inside the bearing chamber.

4. Prevention of paint rust: The characteristic of paint rust is that it is more common in sealed motors. The motor makes a good sound during assembly, but after being stored in the warehouse for some time, the abnormal noise of the motor becomes very loud, and serious rusting occurs when the bearings are removed. Previously, many manufacturers thought it was a problem with the bearings. After our continuous promotion, the motor factory has now realized that the main issue is with the insulation paint. The main reason for this problem is that the acidic substances evaporated from the insulation paint form corrosive substances at a certain temperature and humidity, which corrode the bearing channel and cause bearing damage. At present, the only solution to this problem is to use good insulation paint and assemble it after drying and ventilating for a period of time.

The lifespan of bearings is closely related to manufacturing, assembly, and use, and must be done well in every aspect to ensure optimal operation and prolong the service life of bearings.

PPH bearings provide you with the above content, hoping it can be helpful to you. PPH bearings look forward to working with you! Choose PPH bearings for outer spherical bearings with seats.