The Design and Development of a Light Weight Small Bore Caliper and a Drum-in-Disc Parkbrake 920552
The elimination of asbestos from friction materials in recent years has created some concerns in friction material selection for calipers with integral parking. Non-asbestos friction materials that are suitable for dynamic service braking requirements tend to have poor static performances that are necessary for hill holding. Conversely, materials that have high static coefficient of friction for park braking are susceptible to producing noise in service. These compromising requirements are more pronounced where gross vehicle mass is in excess of 2000 kg. The use of a more costly and heavier braking package comprising a service caliper brake with a separate drum-in-disc parkbrake, each utilising an appropriate friction material, is becoming a favoured alternative and in some applications, mandatory. This paper describes the development of such a brake assembly package for modern vehicle applications which aims primarily at light weight, high performance and competitive cost based on revolutionary design principles. The caliper and the parking drum brake are code named Acacia and Banksia respectively, after native plants of Australia.