Teflon and sintered bronze for lead-free and easily maintained slide bearings
Abstract
Keywords
Citation
(2004), "Teflon and sintered bronze for lead-free and easily maintained slide bearings", Industrial Lubrication and Tribology, Vol. 56 No. 2. https://doi.org/10.1108/ilt.2004.01856bad.004
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:Emerald Group Publishing Limited
Copyright © 2004, Emerald Group Publishing Limited
Teflon and sintered bronze for lead-free and easily maintained slide bearings
Teflon and sintered bronze for lead-free and easily maintained slide bearings
Keywords: Automotive industry, Bearings, Components
Federal Mogul of Wiesbaden, Germany is helping to meet the automotive industry's requirement for lead-free design of all components with its Glycodur F slide bearings made from steel, tin bronze and the fluoroplastic Teflon from DuPont. These maintenance-free, energy-saving components are used in many different applications, such as automotive drive trains and interiors, plant construction and any system involving parts in relative motion that have to operate maintenance-free and yet with extremely low friction and wear. Current applications include the common rail fuel pumps produced by Bosch and Siemens for high-performance diesel engines (Plate 3).
Plate 3
On PIC
Glycodur F slide bearings have a copper- plated steel back, onto which a 0.2-0.4 mm thick, porous layer of tin bronze is sintered. The pores of this layer are filled with Teflon PTFE from DuPont in a rolling process. A 5-30 μm topcoat of the same material is transferred onto parts of the sliding components during the running-in phase to achieve extremely low friction and wear values in operation.
The composite is sliced into strips, which are then cut to length and formed into a ring shape. The joint in the ring is closed when these bushings are press-fitted into the bearing seat. In Glycodur F slide bearings, the good mechanical properties of the sintered bronze are optimally combined with the good slip and lubricating properties of Teflon PTFE. The material structure ensures good dimensional stability and thermal conductivity.
As Dr Achim Adam, Head of Glycodur development at Federal Mogul explains: “We opted for the DuPont fluoroplastic for two main reasons – because the PTFE specialists at this company have given us expert assistance in developing our eco-friendly production process and on account of the excellent batch-to-batch consistency of the PTFE supplied to us as a dispersion – an essential requirement to meet the extremely tight wall thickness tolerances of around 20 μm.”
In the latest generation of common rail diesel pumps, high-precision Glycodur F slide bearings are used for the front and rear shaft mountings and the roller mounting. In this application, the bearings are flooded with fuel injected at a pressure of 1,600 bar and more. The Teflon surface is exposed to peak sliding speeds of 7 m/s and more at pressures of over 15 MPa. For such extreme applications, in which mixed friction must also be possible for a short time, the composite Glyco 92 (Glycodur F) has the necessary reserves up to an operating temperature of 250°C.
Federal Mogul also supplies Glyco 97, an optimised alternative for unlubricated operation, and Glyco 198, for permanently oil-lubricated use. Both these products have a PTFE sliding layer.
For more information, visit Web site: www.dupont.com/teflon