Drive device of variable transmission ratio, particularly for operating an internal combustion engine supercharger.

摘要

The drive device (1) consists of a rotating casing (2) containing a fluid and carrying internally in an idle manner a sun gear (8) and a pair of respective planet gears (12) which mesh with the sun gear (8) and define a gear pump therewith; the fluid is contained in an inner reservoir (7) of the casing, and this latter is provided, in correspondence with the meshing zones between the planet gears and sun gear, with respective intake chambers (16) connected to the reservoir (7), and with delivery chambers (18) closed by automatic valves (20) which are kept closed by the prelor ing of a spring (43) against a ball (42) and arranged to open a a predetermined pressure in order to connect the delivery chambers (18) to the reservoir (7). A pneumatic device (60) also controls a respective shut-off valve (62) in order to connect the delivery chambers (18) to the reservoir (7) independently of the opening of the automatic valves (20).