A hydraulic drive fashioned as one of a rotary or swivel device for NC or CNC controlled machine tools, feeding devices of such machine, manipulators, or robots with several rotary or swivel joints, the hydraulic drive comprising:
- an axial-piston hydraulic motor forming a power drive;
- a follow-up control valve for controlling a pressure medium supply with an electrically controlled desired position value presetting and mechanical actual position value acknowledgement;
- an electric motor provided for the electrically controlled desired position value presetting, said electric motor being be activatable by output signals of a central NC or CNC control unit wherein a rotor of the axial-piston hydraulic motor is rotatably supported by a circular-cylindrical-tubular section of an output shaft thereof on an outer casing surface of an axial extension, the axial-extension being fashioned in a hollow tubular-shape and forming a pivot pin for the rotor of a housing section having said electric motor provided for the desired value presetting with the follow-up control valve being a pivot pin for the rotor of a housing section containing the electric motor;
- control channels which during operation of the hydraulic drive couple a pressure medium alternately fed and discharged through control connections of the follow-up control valve to and from linear cylinders of the rotor arranged in sequence as viewed in a circumferential direction of the rotor, said control channels are formed as sector-shaped outer grooves of the pivot pin and radial transverse channels of the rotor lead to drive channels of the linear cylinders of the rotor;
- and
- supply connections of the follow-up control valve connected to transverse bores of a housing of the follow-up control valve, with the transverse bores terminating in transverse channels of the pivot pin which, as viewed in the circumferential direction of the valve housing are arranged in an offset fashion and are connected by way of correspondingly offset longitudinal channels with connecting nipples arranged at the housing section forming the pivot pin with one of the transverse channels terminating into an inner groove of the circular-cylindrical tubular section of the rotor shaft of the axial-piston hydraulic motor which the circular-cylindrical tubular surrounds the pivot pin and an other of the transverse channel terminating into an outer groove of the pivot pin, a transverse channel of the rotor shaft ending in the outer groove and being located between the inner groove and an end of the rotor shaft on an output side, and one supply connection channel extended from the inner groove of the rotor shaft and the transverse channel to the end of the rotor shaft on the output side.