Stroke volume varying device for hydraulic machine of continuously variable transmission gear-box of vehicle, has piston space that is connectable with another piston space in region of control valve unit based on operating condition

摘要

The device (1) has a piston (7) that is subjected to hydraulic pressure by a valve device (9) in a region of a working surface (7B) that is limited by a piston space (13A), where the hydraulic pressure is provided in a region of a set of hydraulic machines (2, 3). The piston is subjected to a pressure acting in an adjustment direction of axes (5, 6) of the set of hydraulic machines. The piston space is connectable with another piston space (12A) in a region of a high pressure control valve unit (11) i.e. 4-by-2 way valve, based on an operating condition.