Renowned for their continuous, low-wear sliding characteristics, the Schaeffler Group's Permaglide range of plain bearings is celebrating its 25th Anniversary in 2007.
Permaglide plain bearings offer low-wear sliding characteristics, high-load-carrying capacities, and heat-dissipation properties that are normally associated with metals. The bearings are maintenance-free and are therefore excellent for general industrial applications, as well as specialist applications such as those in the automotive industry.
These characteristics are achieved by means of a porous bronze-sintered structure that is applied to a steel or bronze backing, and impregnated with an appropriate polymer-mix. This solid lubricant produces a film between the sliding surfaces, which provides low-noise operation at constant speeds and low coefficients of friction throughout the entire service life of the bearing. The bearings are a low-cost alternative for applications with comparatively low surface loads and where space is restricted.
The bearings are available in the form of bushes, flanged bushes, thrust washers and strips. Custom-designed versions are also possible, including: blanked parts; ball cups; bearing shells; bushes with windows and holes; and bushes with stamped oil grooves. Bush outside diameters are possible from 3mm up to 305mm (in special cases up to 800mm); strip widths up to 250mm can be accommodated and wall thicknesses can be from 0.5-3.06mm.
Permaglide linear plain bearings (PAB) consist of Permaglide bushes pressed into an outer ring. The PABO design has a segment cut out of the bearing for use with supported shafts. Alternatively, Permaglide linear plain bearing units PAGH and PAGBA consist of a Permaglide linear plain bearing (PAB or PABO) pressed into a housing.
For the automotive industry, Schaeffler now offers lead-free Permaglide bearings. Article 4 of the 'End of Life Vehicle Directive' stipulates that, from July 2008, manufacturers of new vehicles will no longer be permitted to use certain materials (including lead) in car components. For this reason, Schaeffler offers a lead-free Permaglide P14 and P141 (with zinc-sulphide) bearings.
P14 is designed for dry-running applications, but can also be used in mixed-friction and hydrodynamic applications. These plain bearings have a running-in layer made from PTFE and zinc sulphide, plus a sliding layer comprising a porous bronze layer filled with PTFE, on a steel backing with a very thin protective layer of tin.
P141 is similar in structure to P14 but is intended for oil-lubricated applications, although the bearings can also be used dry. The running-in layer this time consists of PTFE and zinc sulphide with special wear-inhibiting additives.
For a free Permaglide catalogue, or for more information on Schaeffler's complete range of Permaglide plain bearings, visit www.schaeffler.co.uk or contact the company.
