The effect of graphite morphology (particle size and crystallinity) on friction and wear characteristics of a disc brake lining/cast iron rotor system was evaluated. The friction material consisted of polymer fiber, elastomer, zirconia, baryte and graphite as solid lubricant. Four types of graphites, secondary artificial, natural high purity flake, synthetic flake (Kish) and natural amorphous were used in a disc brake compound. These graphites represent relative extremes of lubricity, impurity levels, and degree of crystalllinity. The volume fraction and particle size of all ingredients were held constant. The total graphite content was fixed at 11.5 vol % which included 7,7 % of coarse (400 - 700 microns) and 3.8 % of fine (80 - 200 microns) graphite. These four types were used individually, and in binary combinations with a total of 16 variations. The brake pads were tested on a dual ended disc brake inertial dynamometer running a 24- hour durability schedule. This included vehicle braking simulations of customer schedules and abusive braking conditions. Measured properties included lining and rotor wear and variation of friction with temperature and pressure. Morphology and composition of transferred film to the rotor surface was investigated using SEM and EDX. The film thickness was also estimated. The results indicate that the graphite morphology does not affect the tribological properties of the brake pad.
Effect of graphite morphology on tribological properties of a disc brake lining
Wirkung der Graphit-Morphologie auf tribologische Eigenschaften eines Scheibenbremsenbelages
1995
15 Seiten, 14 Bilder, 2 Tabellen, 20 Quellen
Conference paper
English
Disc Brake for a Utility Vehicle, and Brake Lining for a Disc Brake
European Patent Office | 2025
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