Some common problems in bearing installation and use

1. Pay attention to the following items when using bearings:

a. Keep the bearing and its surrounding environment clean, even if invisible small dust enters the bearing, it will also increase the wear, vibration and noise of the bearing.

b. When using and installing, be careful. It is not allowed to punch hard, strike the bearing directly with a hammer, or transmit pressure through rolling elements.

c. Use proper and accurate installation tools, try to use special tools, and try to avoid using cloth and short fibers.

d. To prevent the bearing from rusting, when taking the bearing directly by hand, you should fully wash the sweat on your hands and apply high-quality mineral oil before operation. Pay special attention to rust prevention in rainy season and summer.

2. Common problems during installation and use of rolling bearing

2.1 Are there requirements for installation surface and installation site?

yes. If there are iron chips, burrs, dust and other foreign matters in the bearing, the bearing will generate noise and vibration during operation, and even damage the raceway and rolling element. Therefore, before installing the bearing, you must ensure that the installation surface and installation environment are clean.

2.2 Must the bearing be cleaned before installation?

The bearing surface is coated with antirust oil. You must carefully clean it with clean gasoline or kerosene, and then apply clean high-quality or high-speed high-temperature lubricating grease before installation and use. Cleanliness has great influence on bearing life and vibration noise. However, we would like to remind you that totally enclosed bearings do not need to be cleaned and oiled.

2.3 How to select lubricating grease?

Lubrication has a very important influence on the operation and life of bearings. Here is a brief introduction to the general principles of grease selection. The lubricating grease is made of base oil, thickener and additive. The performance of lubricating grease of different types and different brands of the same type varies greatly, and the allowable rotation limit is different. Please pay attention to the selection. The performance of the grease is mainly determined by the base oil. General low viscosity base oil is suitable for low temperature and high speed; High viscosity is suitable for high temperature and high load. Thickener is also related to the lubrication performance, and the water resistance of thickener determines the water resistance of lubricating grease. In principle, greases of different brands cannot be mixed, and even greases with the same thickener will have bad effects on each other due to different additives.

2.4 When lubricating bearings, is it better to apply more grease?

When lubricating bearings, it is a common misconception that the more grease you apply, the better. Excessive grease in the bearing and bearing chamber will cause excessive mixing of grease, resulting in extremely high temperature.

2.5 How to install and remove?

During installation, do not directly hammer the bearing end face and non stress bearing surface. Use blocks, sleeves or other installation tools to evenly stress the bearing. If the mounting surface is coated with lubricating oil, the installation will be more smooth. If the fit interference is large, the bearing shall be put into mineral oil and heated to 90~100 ℃ before installation. In case of difficulty in disassembly, it is recommended that you use the disassembly tool to pull outward and carefully sprinkle hot oil on the inner ring. The heat will cause the inner ring of the bearing to expand, so that it is easier to fall off.

2.6 Is the smaller the radial clearance of the bearing the better?

Not all bearings require the minimum working clearance. You must select the appropriate clearance according to the conditions. In the national standard 4604-93, the radial clearance of rolling bearings is divided into five groups - 2 groups, 0 groups, 3 groups, 4 groups, and 5 groups. The clearance values are from small to large, and 0 group is the standard clearance. The basic radial clearance group is applicable to general operating conditions, conventional temperatures and commonly used interference fit; For bearings working under special conditions such as high temperature, high speed, low noise and low friction, large radial clearance should be selected; For precision spindles and bearings for machine tool spindles, smaller radial clearance should be selected; For roller bearings, a small amount of working clearance can be maintained. In addition, there is no clearance for separated bearings; Finally, the working clearance of the bearing after installation should be smaller than the original clearance before installation, because the bearing should bear a certain amount of load rotation, as well as the elastic deformation caused by bearing matching and load.