The bearing itself performs several main functions: it enables rapid rotation with minimum friction, while supporting high radial or axial loads; it also ensures precise positioning of the shaft, with a greater or lesser capacity to take up misalignments, depending on the type of bearing used. To meet all these requirements, there are several types of bearing, each offering several variants (with flanges, with ceramic balls, without cage...).
Ball bearings offer low friction thanks to point contact, but have limited load capacity. Roller bearings offer high load capacity thanks to linear contact, but higher friction. Rollers can be cylindrical, conical or spherical. Of these three shapes, only the tapered roller can be preloaded to eliminate backlash. The spherical roller bearing uses spherical rollers and offers high load capacity, long life and self-aligning capability in a small footprint. This is the most elaborate and expensive type of bearing.
Faced with such diversity, it is not easy to choose the right bearing for a given application, and then select the mounting and clearances best suited to the bearing's operating conditions (speed, temperature, cleanliness, vibration...).
This article presents the different types of bearings (except needle roller bearings, which are the subject of a separate article), detailing their specific features and the variants of each type. It goes on to explain the rules of design and assembly, including the calculation of clearances - a difficult subject, but one that is essential for sound design.