Unconventional worm gear make it possible to change sliding friction in rolling friction, respectively to reduce the backlash in transmission. The aim of this paper is to determine the mathematical relations which generate the worm grooves surfaces from unconventional worm gear, transmission where the teeth of worm wheel is changed with bearings. Practically this study will perform the determination and writing of an equation which generate the raceway for bearings. This type of gear is an interest from research because it is come with many advantages in comparison with classics worm gears. Based on the studies done about the geometry and kinematics of the gear, followed by a modelling of this gear, the contact areas have been determined as well as some parameters necessary to write generating relations and surfaces descriptions. Thus surfaces determination will be realized taking in to consideration the contact area on the bearing was in gearing and description about this in correlation with rotation move which is made around the worm wheel axis, together with a worm rotation move. Starting from the gearing, seen from the frontal median plane of the worm wheel and inserting a coordinate axis system, will be written the trajectory that the bearing follows, referred once to the worm wheel and then to the worm. Then we make the graphic, representing the worm groove surfaces.