The market requirements for various mechanical devices and instruments using rolling bearings are becoming increasingly strict, and the conditions and performance requirements for outer spherical bearings are also becoming increasingly diverse. In order to select the most suitable outer spherical bearing from a large number of structures and sizes, it is necessary to study from various perspectives. When selecting bearings, it is generally considered that the arrangement, installation, and disassembly difficulty of the outer spherical bearing as the shaft system, the space and size allowed by the outer spherical bearing, and the marketability of the outer spherical bearing roughly determine the bearing structure. Secondly, while comparing and studying the design life of various machinery using bearings and the different durability limits of bearings, the bearing size is determined.

When selecting bearings, it is often biased towards only considering the fatigue life of the bearings, and the fatigue life, wear, noise, and other factors that occur due to the aging of lubricating grease bearings also need to be fully studied. Furthermore, according to different applications, it is necessary to choose bearings with special design requirements for accuracy, NTN bearing clearance, cage structure, lubricating grease, etc. However, there is no specific order or rule for selecting outer spherical bearings. Priority should be given to the conditions, performance, and most relevant matters required for the bearings, which is particularly practical.