Each bearing has its own structural characteristics. In tapered roller bearings, both the roller and the inner and outer raceways are conical. In the process of bearing processing, because the diameter, taper angle and length of roller and ring cone may be deviated, the distance between base surface and the contact between inner and outer cone surface may be affected for the first time.

It is precisely because of this, in the process of tapered roller bearing assembly, the processing quality of the rolling element has a very prominent impact on the bearing assembly quality. In order to further improve the assembly accuracy of tapered roller bearings, most of them adopt random assembly method, which creates conditions for the wide application of bearings.

The so-called random assembly method refers to dividing tapered rollers into a group according to the final processing sequence at the production site, and putting each group of rollers into a special package, or forming components directly with plastic cages; each group of rollers is installed in a set of bearings when the finished product is assembled.

The traditional assembly method of tapered roller bearings is to mix the finished rollers together, and then assemble them into cages by sorting machine or manual size grouping. By contrast, random assembly effectively simplifies the process and does not need to sort the finished rollers, thus saving manpower and material resources, and has better economic benefits.

In the assembling calculation of tapered roller bearings, theoretical analysis and numerical examples prove that the dimension deviation of general bearing matching parts can meet the requirement of the width deviation of finished bearing. Therefore, the interchange method can be used in the assembly of single row tapered roller bearings.

However, in actual production, the factors affecting the width of tapered roller bearings are not only the size deviation, but also the shape and position deviation, in which the convexity of raceway and roller prime line has a greater impact, in addition, the angle deviation of matching parts also has an impact on the width of the bearing. Therefore, the dimension tolerance of parts can be properly compressed to allow some room for dimension calculation.