Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Low abrasion DuPont™ Vespel® thrust washers for maintenance-free SUV transfer case

28.08.2008
Thrust washers made of DuPont™ Vespel® SP-21 polyimide are durable, maintenance-free components of the new Integrated Transfer Cases developed by Magna Powertrain of Lannach, Austria.

Used in premium SUVs from Land Rover and Daimler, these ITC’s are located upstream of the differential to ensure optimum torque transfer between the front and rear axles. In addition they provide the choice between two gear ratios for on-road and off-road driving, whereby selection can be made while driving.


Photo: DuPont
Low-friction and virtually abrasion-free thrust washers, made of DuPont™ Vespel® SP-21, help maximize the service life of the planetary gear train within the new integrated transfer cases from Magna Powertrain.

Two designs of Vespel® thrust washers are used in the planetary gear set for the off-road drive position. In the first design, six small thrust washers. with an outside diameter of 25 mm, absorb axial forces, generated by the helical gearing, from the three planet wheels. In the second, two much larger thrust washers, with an outside diameter of 160 mm, support the ring gear on both sides against the grey cast iron planet carrier. Without the use of the Vespel® thrust washers, the hardened steel planet wheels and ring gear would rotate directly against the comparably soft grey cast iron housing, causing the housing to wear very quickly.

Potential alternatives to Vespel® thrust washers, such as axial needle bearings, would incur relatively high additional costs. Moreover, such bearings require a larger installation space and are significantly heavier. In the quest to find a lightweight, space-saving alternative that was also cost-efficient, the manufacturer followed the advice of Austrian distributor Biesterfeld Interowa, and tested prototype parts made of Vespel®. The results were impressive, as Ernst Riegler, department manager at Magna Powertrain, confirms: “We know of no other material that combines similarly outstanding tribological properties over a wide temperature range with such low space requirement and light weight.”

The complex interaction of mechanical, chemical and thermal stresses in this application makes very high demands on the material. The low-friction Vespel® components can withstand these stresses long-term. As Riegler continues: “We design the Vespel® thrust washers used in our ITCs to last a lifetime operating with PV values of over 7 MPaxm/s. In other words: the reduction in thickness that the thrust washers sustain due to wear is so low that they never need to be changed throughout the entire vehicle service life. The axial positioning of the gear wheels remains within close tolerances and the formation of an optimum lubricating film is guaranteed.”

DuPont produces the thrust washers in-house from polyimide using a direct-forming method similar to metal powder sintering. Directly integrated oil grooves, with geometry flow-optimized by Magna, ensure a permanent thin film of lubricating oil on the thrust washers. The sintered parts require no post-finishing and are ready for immediate installation. At the same time, they meet the very close tolerances specified.

The application advantages of Vespel® SP-21 are not confined simply to low wear. The polymer has a specific gravity of only 1.42 g/cm³ for light weight parts, excellent chemical resistance for stability in a broad range of automotive lubricants and extremely high heat resistance, permitting continuous service temperatures of up to 300 °C.

Vespel® S is a family of highly-durable polyimide parts and shapes that deliver exceptional wear resistance, insulation, and a low coefficient of friction: Vespel® SP-1 combines excellent mechanical and insulation properties at high temperatures; Vespel® SP-21 is enhanced with graphite for very high abrasion resistance; Vespel® SP-211 is enhanced with DuPont™ Teflon® PTFE for a very low co-efficient of friction; Vespel® SP-22 combines low friction and high abrasion resistance with excellent dimensional stability. Further information on these grades and other Vespel® families can be found at www.vespel.com.

The DuPont Engineering Polymers business manufactures and sells Crastin® PBT and Rynite® PET thermoplastic polyester resins, Delrin® acetal resins, Hytrel® thermoplastic polyester elastomers, DuPont™ ETPV engineering thermoplastic vulcanizates, Minlon® mineral-reinforced nylon resins, Thermx® PCT polycyclohexylene dimethylterephthalates, Tynex® nylon filaments, Vespel® parts and shapes, Zenite® liquid crystal polymers and Zytel® nylon resins and Zytel® HTN high-performance polyamides. These products serve global markets in the aerospace, appliance, automotive, consumer, electrical, electronic, healthcare, industrial, sporting goods and many other diversified industries.

DuPont is a science-based products and services company. Founded in 1802, DuPont puts science to work by creating sustainable solutions essential to a better, safer, healthier life for people everywhere. Operating in more than 70 countries, DuPont offers a wide range of innovative products and services for markets including agriculture and food; building and construction; communications; and transportation.

The DuPont Oval, DuPont™, The miracles of science™, and Vespel® are registered trademarks or trademarks of E.I. du Pont de Nemours and Company or its affiliates.

This press release is based upon information provided by:
Magna Powertrain AG & Co. KG; Industriestr. 35, A-8502 Lannach, Austria
Contact: Dipl.-Ing Ernst Riegler
Telephone: +43 (0) 5 04 44 67 11
Email: ernst.riegler@magnapowertrain.com

Horst Ulrich Reimer | Du Pont
Further information:
http://www.magnapowertrain.com
http://www.dupont.com

More articles from Automotive Engineering:

nachricht 3D scans for the automotive industry
16.01.2017 | Julius-Maximilians-Universität Würzburg

nachricht Improvement of the operating range and increasing of the reliability of integrated circuits
09.11.2016 | Technologie Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH

All articles from Automotive Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

New drug reduces transplant and mortality rates significantly in patients with hepatitis C

29.05.2017 | Statistics

VideoLinks
B2B-VideoLinks
More VideoLinks >>>