1. Description of operating phases

Studying the behavior of a synchronizer requires detailed knowledge of the gearshift process. The relative positions of the synchronizer parts, as well as the characteristic points of the synchronized angular velocity and the measured axial force, make it possible to distinguish successive phases. The number of phases depends on the limits of the study and the model developed for the gearshift process. Thus, the number of phases in literature studies varies from four [47] to eleven [16] . In this presentation, the gearshift process is described from the neutral position of the gearshift lever to the end of wheel engagement by the walkman. The gearshift process is divided into eight phases, illustrated in figure