Casquillos De Construccion

Composite dry sliding bearings – maintenance-free and space-saving

Contents
Maintenance-free and space-saving...........................3 Materials .........................................................................6 Machinability of composite materials .............................8 Friction ............................................................................8 Chemicalproperties........................................................9 Selection of bearing size ............................................10 Basic load ratings .........................................................10 Service life.....................................................................11 Requisite bearing size...................................................11 Calculation of service life..............................................13 Application of bearings ..............................................14 Design of associated components ...............................22 Seals .............................................................................23 Lubrication...................................................................24

Mounting......................................................................25

Bearing data – general................................................26

Product tables .............................................................27 Composite bushings with metric dimensions...............27 Composite bushings with inch dimensions ..................34 Composite flanged bushings ........................................38 Compositethrust washers ............................................39 Composite strip ............................................................40 Other related products ...............................................41

Application examples .................................................44

The SKF Group – a worldwide corporation...............54

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Maintenance-free and space-saving
Drysliding bearings of composite material are primarily used for bearing arrangements where heavy loads have to be supported but where rotational or oscillating movements are relatively slow. Because of their good sliding properties and compact design, these plain bearings are particularly suitable for bearing arrangements where • freedom from maintenance is required, • there is a risk of lubricantstarvation, • lubricants should not be used or are forbidden, or • very limited space is available. Typical application areas for SKF composite dry sliding bearings and examples will be found on pages 44 to 52. Characteristics The important characteristics of SKF composite dry sliding bearings include • freedom from maintenance • no lubrication required (PTFE composite) • initial lubrication required(POM composite) • minimum wall thickness, minimum space requirements • can support heavy loads • wide operating temperature range • good sliding properties • practically without stick-slip • little wear • insensitive to edge loads (POM composite) • no machining required The assortment The standard range of SKF composite dry sliding bearings is very comprehensive and meets most needs for this typeof product. The range is shown in the product overview (➔ Table 1 ) and comprises • • • • bushings, flanged bushings, thrust washers, and strip.

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Maintenance-free and space-saving

Bearing

Series

Bore diameter

Lubrication needed

Permissible temperature range

Plain bushings PTFE composite

PCM .. B

3 – 300 mm

No

–200 to +250 °C

PCZ .. B

0,125 – 7 inch

No–200 to +250 °C

POM composite

PCM .. M

8 – 300 mm

Yes, on mounting

–40 to +110 °C short periods +130 °C

PCZ .. M

0,375 – 4 inch

Yes, on mounting

–40 to +110 °C short periods +130 °C

Flanged bushings PTFE composite

PCMF .. B

6 – 35 mm

No

–200 to +250 °C

Thrust washers PTFE composite

PCMW .. B

15 – 52 mm

No

–200 to +250 °C

POM...