ZEN AXK0821 Nadellager (8x21x2)

As an axial needle roller bearing, this bearing carries axial loads in a very low section height. For this ZEN bearing, 8x21x2 mm and a weight of 0.002 kg apply; the specification table holds the further technical particulars. Compared with a ball set of similar section height, the line contact of the needle rollers markedly raises the longitudinal force that can be taken.

The axial needle roller bearing transmits longitudinal force through radially arranged needle rollers that run cage-guided between two axial abutment faces; the slender roller form gives the lowest section height of all axially carrying rolling bearing arrangements while retaining high capacity from the line contact. Depending on the version, the raceways are present as supplied thrust washers or are provided by the surrounding design; in the latter case the mating faces must be hardened, ground and square to the axis.

The design takes no radial forces, and the shaft is to be guided radially elsewhere. As with every axial roller arrangement, sliding relative to the raceway occurs along the roller length, so speed, lubricant supply and heat dissipation must be considered together. Standard bearing steel is through-hardened and covers the usual operating-temperature range; for the design, axial force, available installation height and the quality of the running faces should be assessed together.