NSK 2308-2RSTNG Pendelkugellager (40x90x33)

As a self-aligning ball bearing, this bearing compensates for misalignment and shaft deflection. At 40x90x33 mm and a unit weight of 0.952 kg, the installation envelope is fixed; further technical details are held in the specification table. This variant features a contact seal. This version is meant for bearing positions that are misaligned and dirty at the same time — the combination at which housing sealing alone quickly reaches its limit.

The contact seal on both sides closes off the rolling chamber of the self-aligning ball bearing and thereby takes over two tasks from the adjacent construction: the grease charge stays with the rows of balls, and dust, fibres or moisture do not reach the raceways. That matches the typical application of this design exactly, since self-aligning ball bearings stand where bearing seats are not produced in one setup — on conveyors, blowers, agricultural machinery and textile machinery — and the same environment is usually the dusty one as well.

The design particularity lies in the alignment capability: because the inner ring unit swivels inside the outer ring, the position of the seal relative to its counterface changes with the misalignment; the permissible misalignment of the sealed version is therefore to be taken from the manufacturer's data and not carried over from the open variant.

Added to this is the frictional torque of the bearing lip, which generates heat and pushes the permissible speed below that of the open version of the same size, as well as the temperature and media limits of the seal material. The load-carrying properties remain unchanged: two rows of balls run on the common spherical outer raceway, the low conformity keeps the load rating below that of a rigid ball bearing of the same size, and axial forces are permissible only to a modest extent.

Rings and balls are made of through-hardened standard bearing steel; the normal radial clearance is matched to common fits and operating temperatures.