SKD TRADE, a.s. has been renovating 15T trams for Prague Public Transit Company for several years now. The design of the wheel is characterized by insertion of elastic segments between a wheel hub and a rim which ensures the transmission of driving and braking torque, the transmission of forces arising from the dynamic effects of the vehicle’s own weight and the interaction between wheel and rail. From the beginning rubber compounds of various manufacturers have been used for flexible segments with varying degrees of success because rubber reaches its limits of physical capabilities in a demanding operation of the 15T trams.
SKD TRADE, a.s. moved away from rubber and took a different path – developing a completely new polyurethane (PUR) based material in collaboration with a specialist company. Extensive static, dynamic, noise and vibration tests, including long-term driving tests took place on the 15T trams. PUR segments have succeed in all parameters and now they are homologated and commonly used. The photo shows an assembly of the rim on the wheel hub with inserted PUR segments before pressing.