Influence of bearing configuration quality on operation

Usually, the shaft is supported by two bearings in radial and axial direction. The bearing on one side is called fixed end bearing. It bears both radial and axial loads and plays the role of relative axial displacement between fixed shaft and bearing box. The other side is called the free end, which only bears radial load and can move relative in axial direction.

The fixed end bearing must be fixed with the shaft and bearing housing at the same time. The more suitable bearing is the radial bearing which can bear the composite load, such as deep groove ball bearing, self-aligning roller bearing and double row or paired angular contact ball bearing or tapered roller bearing. The combination of radial bearing with simple radial load, such as cylindrical roller bearing with inner and outer ring without rib, combined with deep groove ball bearing, four point contact ball bearing or bidirectional thrust bearing, can also be used as fixed end bearing. At this time, the second bearing provides two-way axial positioning, but it must be installed with a certain radial distance from the bearing housing. When the length of the free end bearing changes due to thermal expansion of the shaft, there will be no extrusion in the bearing. The axial displacement can occur in the bearing, bearing ring and bearing seat.

"Cross fixing" refers to a bearing configuration in which each bearing is positioned in one direction to the shaft and in the opposite direction. This combination is mainly used for short shafts. All radial bearings that can bear at least one direction of axial load are applicable, including deep groove and angular contact ball bearings, tapered roller bearings and NJ cylindrical roller bearings. When angular contact ball bearings or tapered roller bearings are used, preload must be applied in some cases.

1、 In the stage of bearing selection, many factors (e.g. load, hardness, operating environment, etc.) should be considered. A good bearing design will first make the bearing reach its maximum life value.

2、 For proper storage, bearings should be kept in their original packaging before installation. It needs to be kept in a clean, moisture free and relatively constant temperature environment. Rolling bearings should be kept away from dust, water and corrosive chemicals. Shaking and vibration may permanently damage the mechanical properties of the bearing, so vibration should be avoided during handling and storage. General bearings should be stored horizontally, some heavier bearings will be deformed due to their own weight after a long time of vertical placement! Also, special care should be taken with grease coated (or sealed) bearings, as the density of the grease changes after a long period of storage. When the bearing is used for the first time, there will be a certain degree of rotating noise. Therefore, the shelving time of this kind of bearing should be controlled according to the principle of first in first out!