High-speed-braking performance of rubber brake filled with RB ceramics particles under rain conditions

Abstract

We developed a brake shoe made of a fluorine-contained rubber (FKM) compound filled with rice bran ceramics (RBC) particles for a caliper brake of bicycle and evaluated the braking performance and tribological properties on the wet condition from high running speed to stopping. In addition, we investigated the influence of the RBC particles on the braking performance and tribological properties. The test apparatus consisted of an actual bicycle and imitated a rainy condition. The brake wire pull force was 60 N, which corresponded to a low grip force. We manufactured FKM shoe and RBC-contained FKM rubber (FKM/RBC) shoe as the test samples. A well-regarded commercially available rubber shoe, which included hard inorganic fillers, was compared with the other test samples. The FKM and commercialized shoe samples exhibited the high friction coefficients in the initial stage of test cycle whereas the coefficient of the commercialized shoe rapidly decreased with the test cycles. The FKM/RBC shoe sample had the stable and high friction coefficients irrespective of test cycle. The specific wear rate of the FKM/RBC shoe was much smaller than the other samples. Furthermore, the aggressiveness to the rim was lower for the FKM/RBC shoe than that for the commercialized shoe. We concluded that the RBC filler possessed the characteristics to maintain the braking performance irrespective of duration of use and to reduce the wear of the shoe and rim under rainy conditions.