The choice of bearing clearance and configuration is an extremely important part of the motor design, and the solution chosen without knowing the performance of the bearing is likely to be a failed design. Different operating conditions have different requirements for bearings.

The purpose of bearing lubrication is to separate the rolling element and the rolling surface with a thin oil film, and form a uniform lubricating oil film on the rolling surface during operation, thereby reducing the internal friction of the bearing and the wear of each element, preventing sintering. Good lubrication is a necessary condition for the bearing to work. Analysis of the causes of bearing damage shows that about 40% of the bearing damage is related to poor lubrication. Lubrication methods are divided into grease lubrication and oil lubrication.

Grease lubrication has the advantage that it does not need to be replenished for a long time after filling with grease once, and the sealing structure is relatively simple, so it is widely used. Grease is a semi-solid lubricant made of lubricating oil as the base oil and mixed with a solid thickener with strong lipophilicity. In order to improve some characteristics, various additives are also added. Oil lubrication, often including circulating oil lubrication, jet lubrication, and oil mist lubrication. The lubricating oil for bearings is generally based on refined mineral oil with good oxidation stability and rust resistance, and high oil film strength, but various synthetic oils are often used.

The bearing arrangement of the rotating parts of the motor (such as the main shaft) usually needs to be supported by two sets of bearings, and the rotating part is positioned radially and axially relative to the fixed part of the machine (such as the bearing seat). Depending on the application conditions, such as load, required rotational accuracy and cost requirements, bearing arrangements can include the following: Bearing arrangements with fixed and floating ends Pre-adjusted bearing arrangements (fixed at both ends) ” “Floating” fine bearing configuration (both ends float)

The fixed end bearing is used for radial support at one end of the shaft and for axial positioning in two directions at the same time. Therefore, the fixed end bearing must be fixed on the shaft and the bearing housing at the same time. Bearings suitable for use at the fixed end are radial bearings that can withstand combined loads, such as deep groove ball bearings, double row or paired single row angular contact ball bearings, self-aligning ball bearings, spherical and roller bearings or matched tapered roller bearings. sub bearing. Radial bearings that can only bear pure radial loads, such as solid cylindrical roller bearings with one ring without ribs, and other types of bearings (such as deep groove ball bearings, four-point contact ball bearings or bidirectional thrust bearings) etc.) can also be used at the fixed end when used in groups. In this configuration, the other bearing is only used for axial positioning in two directions, and a certain degree of radial freedom must be left in the bearing seat (ie, clearance should be reserved with the bearing seat).

The floating end bearing is only used for radial support at the other end of the shaft, and the shaft must be allowed to have a certain axial displacement, so that there will be no mutual force between the bearings. For example, when the bearing expands due to heat, the axial displacement can be Some types of bearings are implemented internally. Axial displacement can occur between one of the bearing rings and the part to which they are connected, preferably between the outer ring and the housing bore.