INANK73/25-XLMachined Needle Roller Bearing – 73 mm Roller Bore, 90 mm OD, 25 mm Width, Ribbed Outer Ring, Open, X-life

Product Description

What this part is

INA NK73/25-XL single-row machined needle roller bearing. Roller Bore (Fw): 73 mm. Outside Diameter: 90 mm. Overall Width: 25 mm. Number Of Rows: 1. Rolling Elements: Needle rollers. Closure Type: Open. Bore Type: Straight. Bearing Material: Bearing steel. Dynamic Load Rating: 60 kN. Static Load Rating: 100 kN. Fatigue Limit Load, radial: 17.5 kN. Reference Speed: 3 900 r/min. Limiting Speed: 6 000 r/min. Minimum Chamfer Radius: 0.6 mm. Item Weight: 302 g (0.67 lb).

Decoding the designation

NK — machined needle roller bearing with a ribbed outer ring, the needle rollers running directly on the shaft.

73 — 73 mm roller bore, the diameter of the shaft raceway the needles run on.

25 — 25 mm overall width.

XL — Schaeffler X-life, a reinforced execution with upgraded raceway quality and a higher load rating than the pre-XL part of the same size.

What these specs mean in practice

A machined needle roller bearing puts the highest possible radial capacity into the smallest radial section: 60 kN dynamic and 100 kN static in a ring only 8.5 mm thick on radius.

A static rating well above the dynamic rating is normal for a needle roller section. Line contact across a full complement of long rollers resists permanent indentation far better than it resists rolling fatigue.

Reference Speed 3 900 r/min is the thermally-based figure; Limiting Speed 6 000 r/min is the mechanical ceiling.

The ribs on the outer ring guide the roller set axially and retain it as a unit for handling and fitting.

Mounting data

Shaft raceway diameter: 73 mm. The shaft seat is the inner raceway, so it is hardened and ground to bearing raceway quality rather than finished as a plain fitting diameter. Minimum Chamfer Radius: 0.6 mm.

Quantity and configuration

Unit Quantity: 1 Pc. Single bearing, open both faces, outer ring with ribs and roller set.

Interchange guidance

NK73/25 is the pre-X-life execution on the same 73 x 90 x 25 mm envelope and carries lower load ratings, so the 60 kN and 100 kN figures above belong to the XL part only. An IR inner ring can be added where the shaft cannot be hardened, which changes the bore to the inner ring bore.

Searchable designation forms: NK73/25-XL, NK 73/25 XL, NK7325XL, NK-73/25-XL, NK 73/25.