Abstract: An automatic transmission, in particular an infinitely variable automatic transmission for motor vehicles, contains a radial piston pump (1) for supplying a hydrodynamic converter (3), a lubricating device and control and actuating devices of the automatic transmission via a number of control conduits. Radially outside of its outlet valves, the radial piston pump (1) contains an annular chamber (22), which extends around the radial piston pump (1). The annular chamber (22) is embodied as a damping chamber and is mainly arranged in a recess (23) of the converter housing (2), and therefore almost completely outside of the pump housing (17). The annular chamber (22) is bordered by the recess (23) of the converter housing (2), the pump housing (17) and/or a separate pump cover (24). The annular chamber (22) is not symmetric and with its volume extends into the adjoining free spaces of the automatic transmission.

Abstract: An actuating system is provided that includes a differential hydraulic cylinder containing a piston and a piston rod connected to one side of the piston. A first or head chamber (53) is defined in the cylinder and is bounded by the one side of the piston, to which the piston rod is not connected. A second or rod chamber (54) is also defined in the cylinder and is bounded by the other side of the piston, to which the piston rod is connected. An actuatable assembly is provided that is adapted to be connected to either the hydraulic cylinder or the piston rod. Finally, a proportional control valve is provided which is adapted to actuate the hydraulic cylinder by controlling the amount of fluid supply to the first chamber, wherein the supply pressure is connected to the second chamber.