GB1392707A

GB1392707A - Variable-ratio frictional drive gears

Info

Publication number: GB1392707A
Application number: GB3531871A
Authority: GB
Original assignee: Rotax Ltd
Current assignee: Lucas Support Services Ltd
Priority date: 1971-07-27
Filing date: 1971-07-27
Publication date: 1975-04-30
Also published as: IT961680B; SE370775B; JPS5718057B1; DE2236290A1; FR2147720A5; NL164648B; DE2236290B2; NL7210390A; DE2236290C3

Abstract

1392707 Variable speed gear ROTAX Ltd 13 July 1972 [27 July 1971] 35318/71 Heading F2D In a toric disc friction gear, for, e.g. constant speed drive of an aircraft alternator, wherein processional roller-tilt shift is initiated by tangential shift of roller carriages, the tangential shift is effected through an articulated link 33 by axial movement of an inner piston 35, which slides in a slidable outer piston 36 under the influence of the following forces. The leftward thrust of the link 33 under roller torque reaction is opposed by line pressure supplied by a pump through port 39 and passages 45 ... 51 to a space 52 ahead of the inner piston 35, and by output speed responsive governor pressure supplied from line port 39, through the above named passages, port 40, output driven centrifugal governor valve 28, port 42 and passages 57, 58 to a space 59 ahead of the outer piston 36. After a predetermined rightward travel of the inner piston 35 relative to the outer 36, a land 55 on the inner rides off an exhaust passage 54 in the outer, and thereby reduces line pressure. The arrangement is such that, during steady load state, line pressure acting in the inner space 52 on the area of the inner piston 35 balances governor pressure acting in the outer space 59 on the larger area of the outer piston 36, so that a constant ratio (that between the piston areas) exists between line and governor pressures and 66 is restored after every load change, output speed being held to the required value by the governor valve spool 67 occupying a position with a land 69 midway over the output port 70. Since the steady state forces in the spaces 52, 59 balance, the only force acting on the shift link to oppose torque reaction is that of the pressure in the space 52, and this pressure is transmitted to separate pistons of the remaining roller carriages to produce simultaneous shift thereof, and is also fed to an end-loading piston (23, Fig. 1, not shown), for applying traction pressure to the rollers.