The design and the optimization of the fork-pin compression joints in front motorbike suspensions

The design of the fork-pin compression-fit joints of front motorbike suspensions is uncertain mainly because of the poor knowledge about the starting friction coefficient µll and about the mean coupling pressure p. The axial releasing force Fll=µll∙p∙A, which is the fundamental design parameter, depends on the mentioned two factors, usually unknown, and on the coupling surface dimension, usually known. In this work are presented two methodology which are usefull to calculate the µll and the p parameters. The µll mathematical model has been defined as a function of the production specifications of the components whereas the definition of the coupling pressure was obtained going on improving some methodologies already proposed by the authors.