Engineering
SL plain bearings are fundamentally suitable for all sliding movements or combinations of motion. Custom designs can be manufactured according to customer drawings, with the lubricant arrangement either verified or defined at the factory.
A bearing length of 0.75 x d up to a maximum of 1.25 x d is recommended. Bearings that are too short will have an insufficiently secure fit in the bore and therefore reduced load capacity; with longer bearings, installation becomes more difficult.
To avoid edge pressure in the event of misalignment, the bearing bore (sliding surface) can be provided with appropriate relief chamfers. For greater misalignment errors, which may occur for example in larger welded structures, the use of spherical plain bearings is recommended.
For inner diameters up to 500 mm and temperatures up to 80°C, the following fits are recommended for dry-lubricated plain bearings:
| Variant 1 | ||
|---|---|---|
| Plain-bearing bore: | E7 (results in approx. H9 after press-fitting) | |
| Plain-bearing outside diameter: | s6 or r6 | |
| Shaft (axle): | c8 or d8 | for heavy loads |
| e7 | for light loads | |
| f7 | for highest accuracy | |
| Housing bore: | H7 |
| Variant 2 | |
|---|---|
| Plain-bearing bore: | C7 (results in approx. D8 after press-fitting) |
| Plain-bearing outside diameter: | s6 or r6 |
| Shaft (axle): | h7 |
| Housing bore: | H7 |
Other fits are permissible, provided that a secure seating of the plain bearing in the bearing housing is achieved and the required operational running clearance in the bearing bore is guaranteed.
| Required Surface Finishes | |
|---|---|
| haft: | Ra ≥ 0.2 and Ra ≤ 0.8 |
| Plain-bearing bore: | Ra ≈ 1.2 |
| Plain-bearing outside diameter: | Ra ≈ 3.2 |
| Bearing-housing bore: | Ra ≈ 3.2 |
Mating material
The mating material should have a minimum surface hardness of material hardness + 100 HB, as well as a surface finish between Ra ≥ 0.2 and Ra ≤ 0.8.
Particularly for use in water and liquids, corrosion-resistant steel is recommended as a suitable mating material. If the shaft is hard chrome-plated, corrosion protection can also be achieved; the hardness must then be a minimum of 800 HV and the coating thickness > 50 μm.
HV = Vickers hardness HB = Brinell hardness
As an alternative, shrink-fitting a sleeve, welding on stainless steel sheet with subsequent finishing, or treatment in a salt nitriding bath can be considered.
