Construction

SL plain bearings are generally applicable for all sliding motions or motion combinations. Special constructions can be made according to the customers drawings. In this case the arrangement of the dry lubricants will be checked or defined by the company.

The recommended length of the plain bearing is 0,75 x d up to 1,25 x d.

Plain bearings which are too short have an insufficiently fit in the housing which results into a lower load capacity. If the plain bearings are too long, they can only be mounted with difficulty.

In order to avoid edge pressures due to misalignments, the plain bearing bore holes (sliding surface) can be supplied with load relieving chamfers. If the resulting misalignments are to high, which could happen at welded constructions for example, the use of a spherical ball bearing is recommended.

Up to an inside diameter of 500 mm and a temperature up to 80°C the following fits for plain bearings are recommended:

     Version 1.
plain bearing inner diameter: E7 (decreases down to H9 after pressed-in)
plain bearing outer diameter: s6 or r6
shaft:
c8 or d8 for high load
e7 for light load
f7 for high precision
housing: H7
     Version 2.
plain bearing inner diameter: C7 (decreases down to D8 after pressed-in)
plain bearing outer diameter: s6 or r6
shaft: h7
housing: H7

Other fits are possible if a safe fit of the plain bearing in the housing is achieved and the required operational bearing clearance in the plain bearing bore hole is given.

required surface qualities
shaft: Ra  0,2 and Ra ≤ 0,8
inside plain bearing: Ra ≈ 1,2
outside plain bearing: Ra ≈ 3,2
housing bore hole: Ra ≈ 3,2

Mating material

The mating material should have a minmal surface hardness of bearing material hardness + 100 HB as well as a surface quality between Ra  0,2 and Ra ≤ 0,8.

Especially for the use in water and liquids corrosion-resistant steel is recommended as a suitable mating material. Protection from corrosion may also be achieved if the shaft is hard chrome plated. Then the required hardness must be at least 800 HV and the layer thickness > 50 μm.

HV = Vickers hardness
HB = Brinell hardness

The shrink fitting of a collet or the welding of stainless steelplate on the shaft with a rework or a salt bath nitriding can be seen as alternatives.