The needle roller bearings have a minimum radial size, especially if they are used without an inner ring and therefore require a shaft hardness, which in this case will also be expressed as a raceway, of at least 58 Hrc.Only in cases where load capacity and duration lower than the nominal ones are required, lower hardness values will be considered.
The outer rings of the roller cases are thin and hardened and are obtained by means of a deep precision padding of steel sheet, whose thickness is calibrated; they can be full complement (i.e. with the rollers joined and held by an appropriate system), or as a non-separable group with a guide cage held and centered laterally.
They can also be supplied, when necessary, with adequate protection systems positioned laterally to the cages. They can also be available in an open or closed version with a back; if the shaft heat treatment is not provided, we can provide a dedicated inner ring.The cases, mounted with considerable interference in the seat, follow its precision and shape. It goes without saying, therefore, that this must be as uniform as possible dimensionally and structurally rigid, in order to avoid local deformations of the outer ring, which would compromise its operation.
The interference of assembly therefore makes it unnecessary to adopt lateral sealing solutions which, combined with the limited size, give life to a very convenient system whenever assembly solutions in limited spaces are required.