GB906002A - Improvement in or relating to power transmission devices for friction type change speed gearing arrangements. - Google Patents

Abstract

906,002. Variable-speed friction gear. SOC. DES FABRICATIONS UNICUM. Jan. 9, 1959 [Jan. 9, 1958], No. 890/59. Class 80 (2). In a variable-speed friction gear of the kind wherein single or twin friction discs (Fig. 1, not shown) drive an axially movable friction disc 6 through bi-conical friction rollers 5, the disc 6 is connected to an output shaft 7 by means varying the pressure between the engaging friction surfaces in response to variations in transmitted torque comprising torque transmitting, coacting helical cam surfaces 12<SP>3</SP>, 14<SP>1</SP> as shown, or cam and ball recesses, respectively on the member 12 of the wheel 6 and on a member 14 splined in the bore of the output shaft and reacting on the said output shaft through abutment means 15 (not described) automatically taking up play, and a spring 11 interposed between the wheel 6 and the output shaft 7 exerts a continuous pressure additive to the torque responsive pressure. As shown the cam surfaces 12<SP>3</SP>, 14<SP>1</SP> each comprises two pairs of opposed ramps each equal to a quarter of the pitch of a coarse, square, screw thread. The spring 11 abuts the wheel 6 through a ball thrust bearing 13 and the output shaft through a bearing member 7<SP>1</SP> guiding the member 12.