Abstract: A hydrostatic axial piston machine (1) with a cylinder barrel (2) having at least one piston bore (3) in which is located a power unit piston (4) supported on a cam disk (18). A control surface (5) is stationary relative to the housing and is on a control base (6), against which control surface the cylinder barrel (2) is in contact. In the control base (6) there are a kidney-shaped inlet connection (8) and a kidney-shaped outlet connection (9). The sealing web surface on the control surface 5 on the control base (6) in the vicinity of the inlet connection (8) is reduced, so that in operation as a motor, when there is a pressurization of the inlet connection (8), a reduction of the hydrostatic relief force is achieved. In operation as a motor, a residual application of the cylinder barrel (2) against the control surface (5) from a hold-down force of a hold-down spring (24) that is in an operative connection with the cylinder barrel (2) and/or pressing cylinder compression forces is preserved.

Abstract: A hydrostatic power unit (2) comprises a variable displacement machine with a continuously variable displacement volume and is operated as a pump and motor and is in a drive connection with an internal combustion engine (3). When operated as a pump, the power unit sucks hydraulic fluid out of a tank (9) and delivers into a delivery side (P), and, when operated as a motor, functions as a hydraulic starter to start the internal combustion engine (3). When operated as a motor, the power unit is supplied with hydraulic fluid from a hydraulic accumulator (30). The displacement volume of the power unit (2) is set by a displacement volume control device (60) actuated by a positioning piston device (61) supplied with hydraulic fluid from a charging pressure circuit (23). The power unit (2) includes a supplemental positioning piston device (80) in an operative connection with the displacement volume control device (60) and which is actuated directly by the pressure present in the hydraulic accumulator (30).

Abstract: A hydrostatic power-unit (7) is connected with an internal combustion engine (2). The suction side (S) of the power-unit (7), when operating as a pump, sucks hydraulic fluid from a tank (9) and delivers into a delivery side (P), and when operating as a motor is driven by hydraulic fluid from a hydraulic accumulator (20). A check valve device (30) is located in the suction side (S) to provide a pressure increase when the power-unit (7) is operated as a motor. The check valve device (30) has a check valve (32) operated by an actuator device (31). The actuator device (31) actuates the check valve (32) between a closed position (32a) in which a connection of the suction side (S) with the tank (9) is shut off, and an open position (32b) in which the connection of the suction side (S) to the tank (9) is opened.

Abstract: A power split transmission (LG) of vehicle a traction drive (F) includes a continuously variable transmission (G) and a summing transmission (SG). The continuously variable transmission (G) has a primary unit (P) and a secondary unit (S) driven by the primary unit (P). The primary unit (P) has a driveshaft (TW1) connected, directly and without the interposition of a clutch device, with the sun gear (SR) of the summing transmission (SG). The secondary unit (S) has a driveshaft (TW2) connected, without the interposition of a clutch device, with a ring gear (HR) or a planetary carrier (PT) of the summing transmission (SG). The planetary carrier (PT) or the ring gear (HR) of the summing transmission (SG) form an output element of the summing transmission (SG), which is in a driving connection with the wheel drive.

Abstract: A variable displacement hydrostatic power unit (7) is in a drive connection with an internal combustion engine (2). When operated as a pump, the power unit (7) delivers hydraulic fluid to at least one consumer (V). When operated as a motor, the power unit (7) is a hydraulic starter for the internal combustion engine (2) and is supplied with hydraulic fluid from a hydraulic accumulator (25). The displacement volume of the power unit (7) is set by a displacement volume control device (50) actuated by a positioning device (52). The displacement volume control device (50) is displaced into a position with maximum displacement volume by a corresponding actuation of the positioning device (52) chronologically prior to the shutoff of the internal combustion engine (2). A securing device (60) holds the displacement volume control device (50) in the maximum displacement volume position when the internal combustion engine (2) is shut off.

Abstract: A drive train (1) includes an internal combustion engine (2) and working hydraulics (4) having at least one hydraulic pump (7). When operated as a pump, the hydraulic pump (7) sucks hydraulic fluid from a tank (9) and delivers into a delivery line (10) that leads to the working hydraulics (4). When operated as a motor, the hydraulic pump (7) is supplied with hydraulic fluid from a hydraulic accumulator (25). The drive train (1) has a charge pump (20) to supply a charging circuit (23). The charge pump (20), when operated as a pump, sucks hydraulic fluid out of the tank (9) and delivers into a charge pressure line (22) that leads to a charging circuit (23), and the charge pump (20) when operated as a motor is supplied with hydraulic fluid from the hydraulic accumulator (25).

Abstract: A variable displacement hydrostatic power unit (7) is connected with an internal combustion engine (2). The power unit (7) operates as a pump to deliver hydraulic fluid to at least one consumer (V) and operates as a motor as a hydraulic starter for the internal combustion engine (2). Hydraulic fluid from a hydraulic accumulator (25) is supplied to the power unit (7) operated as a motor. The power unit (7) includes a spring device (55) which, when the internal combustion engine (2) is shut off, actuates a displacement volume control device (50) into a position with the maximum displacement volume. When the power unit (7) is actuated with hydraulic fluid from the hydraulic accumulator (25), the internal combustion engine (7) is immediately started by the power unit (7) without the need for an immediately preceding adjustment of the displacement volume control device (50) of the power unit (7).

Abstract: A drive train (1) has an internal combustion engine (2), a traction drive (3), and working hydraulics (4) having at least one hydraulic pump (7). A connecting line (26) leads to a hydraulic accumulator (25) and is connected to a delivery line (10) of the hydraulic pump (7) that leads to the working hydraulics (4). A shutoff valve (30) is located in the connecting line (26). The shutoff valve (30) is a check valve (31) that opens automatically and as a function of the pressure to allow a flow to the hydraulic accumulator (25). A pressure relief valve (32) is operatively associated with the connecting line (26) between the shutoff valve (30) and the hydraulic accumulator (25).

Abstract: A hydrostatic starter device (10) for an internal combustion engine (2) having a hydrostatic power unit (11) connected with the output shaft (4) of the internal combustion engine (2) is driven with hydraulic fluid from a hydraulic fluid accumulator (12). The hydrostatic starter device (10) has an electrohydraulic charging device (30) to charge the hydraulic fluid accumulator (12) with hydraulic fluid and the hydrostatic power unit (11) is in a drive connection by a clutch device (25) with the internal combustion engine (2). The hydrostatic power unit (11) can be connected in a drive connection with the internal combustion engine (2) by the clutch device (25).

Abstract: A hydrostatic positive displacement machine (1) with a variable displacement volume includes a cradle (3) pivoted by a hydraulic positioning device (7) having a positioning piston device (8). A position-controlled control valve (10) generates a control pressure and includes axially displaceable and locked setting valve means (20) and the rotatable feedback valve means (21). Control cross sections are exposed by an axial displacement of the setting valve means (20) relative to the feedback valve means (21) and are closed by rotational movement of the feedback valve means (21) relative to the setting valve means (20).

Abstract: A drive train of a vehicle has a drive motor and a traction drive driven by the drive motor. A hydraulic work system has at least one hydraulic pump driven by the drive motor. To deliver torque into the drive train and/or to absorb torque from the drive train, the drive train is provided with an additional hydraulic machine which can be placed in communication with a hydraulic pressure accumulator and/or a tank and can be operated as a pump and a motor in the same direction of rotation. The hydraulic machine has an inlet connection and an outlet connection and a switching valve device is provided to control the connection of the inlet connection and the outlet connection with the pressure accumulator or the tank.