Abstract: A hydrostatic pump (1) with a variable delivery volume can be operated in a closed circuit. An electrically controllable actuator device (4) is provided for the control of the delivery volume of the pump (1). The electrically controllable actuator (4) has an electrically actuatable control valve device (6) which generates a positioning pressure which actuates a positioning piston device (5) which is in an operative connection with a delivery volume control device (3) of the pump. An electrical position feedback circuit (21) of the delivery volume control device (3) is provided and the actuator device (4) is provided with a switchable hydraulic neutral position control system (25), by means of which a restoring movement can be generated that acts on the positioning piston device (5) and places the delivery volume control device (3) into a neutral position.

Abstract: A hydrostatic pump (1) has a mechanical displacement volume control with a mechanical control element (4), which for generation of an actuator pressure that acts on a positioning piston (5) which is functionally connected with a displacement setting device (3), has a position-controlled control valve (6) functionally connected with a control lever (30) and with the displacement setting device (3) of the pump (1). A pump with a mechanical displacement volume control with a pressure limiting function can be accomplished by mechanically decoupling the control lever (30) from the displacement setting device (3) whereby a pressure cutoff function is provided, with which, by respective pilot valves (21a, 21b), a pressure signal can be generated from a delivery line (2a, 2b) of the pump (1), which signal is transmitted via the control valve (6) to the positioning piston (5) and counteracts the control pressure.

Abstract: A hydrostatic pump (1) with a variable displacement volume can be operated in a closed circuit and is driven by a drive engine (2), in particular by an internal combustion engine. To control the displacement of the pump (1), a control device (4) is provided which can be actuated as a function of the speed-dependent control pressure which is a function of the speed of the drive engine (2). To improve the control characteristics of the pump, a switchover device (35) is provided, by which the pump (1) can be switched between a speed-dependent displacement control by the speed-dependent control pressure and a volume flow-dependent delivery control, in which the control device (4) of the pump (1) can be controlled as a function of the actuation of an actuator mechanism (28).

Abstract: A hydrostatic pump (1) with a variable delivery volume can be operated in a closed circuit. An electrically controllable actuator device (4) is provided for the control of the delivery volume of the pump (1). The electrically controllable actuator (4) has an electrically actuatable control valve device (6) which generates a positioning pressure which actuates a positioning piston device (5) which is in an operative connection with a delivery volume control device (3) of the pump. An electrical position feedback circuit (21) of the delivery volume control device (3) is provided and the actuator device (4) is provided with a switchable hydraulic neutral position control system (25), by means of which a restoring movement can be generated that acts on the positioning piston device (5) and places the delivery volume control device (3) into a neutral position.

Abstract: A hydrostatic pump (1) has a mechanical displacement volume control with a mechanical control element (4), which for generation of an actuator pressure that acts on a positioning piston (5) which is functionally connected with a displacement setting device (3), has a position-controlled control valve (6) functionally connected with a control lever (30) and with the displacement setting device (3) of the pump (1). A pump with a mechanical displacement volume control with a pressure limiting function can be accomplished by mechanically decoupling the control lever (30) from the displacement setting device (3) whereby a pressure cutoff function is provided, with which, by respective pilot valves (21a, 21b), a pressure signal can be generated from a delivery line (2a, 2b) of the pump (1), which signal is transmitted via the control valve (6) to the positioning piston (5) and counteracts the control pressure.

Abstract: A hydrostatic pump (1) with a variable displacement volume can be operated in a closed circuit and is driven by a drive engine (2), in particular by an internal combustion engine. To control the displacement of the pump (1), a control device (4) is provided which can be actuated as a function of the speed-dependent control pressure which is a function of the speed of the drive engine (2). To improve the control characteristics of the pump, a switchover device (35) is provided, by which the pump (1) can be switched between a speed-dependent displacement control by the speed-dependent control pressure and a volume flow-dependent delivery control, in which the control device (4) of the pump (1) can be controlled as a function of the actuation of an actuator mechanism (28).