Design of bearing arrangements

Location of bearings

For moderate loads (0,035 C < P ≤ 0,05 C), the shaft seats for Y‑bearings should be machined to an h7 tolerance. For light loads and low speeds, an h8 shaft tolerance is sufficient.

Operating environment

Since high temperature bearings are supplied without preservative oils and must be used without grease or oil lubrication, the anti-corrosion property of the bearings is limited. Therefore, the bearings should be used in a dry environment or with a proper sealing arrangement to keep the bearings dry.
The most common sealing alternatives for high temperature Y-bearings incorporate integrated or external shields or labyrinth seals. These arrangements have a rather low complexity and none of these arrangements are capable of keeping the bearing dry in a wet environment.

Axial shaft elongation

To accommodate axial shaft elongation, the shaft on the non-locating side should be provided with either one groove, or two grooves located 120° apart, to engage a modified grub screw:

  • Hexagon socket grub (set) screws with a dog point, in accordance with ISO 4028:2003, but with a fine thread according to the product table. The grub screw should be secured by a nut and spring washer or star lock washer (fig. 1).
  • Slotted pan head screws in accordance with ISO 1580:2011, but with fine thread according to the product table, locked with a spring or star lock washer (fig. 2).

The screws and groove(s) accommodate changes in shaft length and prevent the shaft from turning independently of the bearing. The ends of the grub screws should be ground and the sliding surfaces in the shaft grooves coated with a lubricant paste suitable for the operating temperature.

SKF logo