Asli Arslan

Keramik für den Einsatz in Bremsen und Kupplungen

Eine weitere Steigerung der Leistungsdichte von Kupplungen und Bremsen ist mit herkommlichen Reibwerkstoffen fast nicht mehr moglich. Reibbelage auf der Basis von Sintermetallen erlauben eine hohere Leistung als organische Reibbelage, jedoch haben sie gravierende Nachteile in Bezug auf Komforteigenschaften, so dass sie im Pkw nicht eingesetzt werden konnen. Erfolg verspricht die Anwendung von neuartigen keramischen Werkstoffen, mit denen sich der folgende Aufsatz des Instituts fur Maschinenkonstruktionslehre und Kraftfahrzeugbau der Universitat Karlsruhe naher befasst.

Increasing the Performance of Motor Vehicle Clutches by the use of Ceramics as Friction Material and the resulting Effects on System Design

The experimental and constructive results illustrate that engineering-ceramic materials have a high potential in the field of dry running friction systems. According to first estimations, it is possible to build the vehicle clutch 53% smaller or to transmit up to 180% higher torque with the same size by an appropriate selection of the system friction pairing and an adequate ceramic design [1, 2]. The friction coefficient characteristic (decreasing friction coefficient above sliding speed) is unfavourable with regard to comfort (self-induced grab oscillations [3]) of the vehicle clutch. Furthermore, it is important to select the test procedure of the experimental analyses to be as close to the system as possible in order to obtain exact information concerning the target system.Copyright

Ceramics for use in brakes and clutches

A further increase in the power density of clutches and brakes is hardly possible using conventional friction materials. Although friction linings on the basis of sintered metals allow higher power densities than organic linings, they have serious disadvantages with regard to comfort, which means that that they cannot be used in vehicles. The use of innovative ceramic materials here is promising, as is shown by the following article from the Institute of Machine Design and Automotive Engineering of the University of Karlsruhe.