Low-friction plain bearings for lubricated applications
Self lubricating metal-polymer bearings provide a cost effective solution
to reducing friction and wear, writes Derek Marsella, and bearings of
this type can be found operating successfully in virtually every sector
of engineering. But the market demands in respect of these components has
intensified. Better economy, higher power outputs, less environmental
pollution, more compact equipment, reduced maintenance and increased
efficiencies are now the rule of the day, and GGB (Glacier Garlock
Bearings) has responded with a variety of new products.
The design of a metal-polymer plain bearing is a challenging task and
requires careful consideration of such key properties as friction, wear
rate, 'embeddability', conformability, temperature stability, fatigue
strength and, in the case of lubricated environments, resistance to
cavitation erosion, flow erosion and chemical attack. For example, the
advent of high-power automotive diesel engines has resulted in new fuel
pump designs that require the bearings to operate under high loads and
speeds with lubrication provided by the low-viscosity fuel. In this
environment the bearings must not only exhibit low wear, but also resist
both cavitation damage from the fuel, and chemical attack by the fuel
additives
GGB's latest metal-polymer product release, DP31, was specifically
developed to meet the requirements of such demanding applications without
compromising wear performance. The exceptionally low lubricated friction
of the material, moreover, is creating other opportunities, particularly
in the strut and shock absorber market where friction is a most critical
performance requirement for the suspension systems of light-duty vehicles.
In response to an increasing incidence of reported fatigue damage in the
metal-polymer bearings of gear pumps and compressors, GGB recently
introduced DP30. The composition of DP30 was developed to provide
improved plasticity in the bearing lining, whilst maintaining the
required wear resistance. Rig testing by both GGB and its customers has
shown DP30 to offer very high resistance to fatigue damage.
Glacier Garlock Bearings changed its name to GGB from the beginning of
this month. As GGB president Bernd Fischer explains: We're still the
same company under the same ownership. But just as our bearings make it
easier to reduce friction, we're making it easier to say our name!
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