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 drive has a hydrostatic pump (3) driven by a drive motor (2) and connected in a closed circuit with a hydrostatic motor (4). The closed circuit is formed by a first hydraulic connection (6a) and a second hydraulic connection (6b). Each of the hydraulic connections (6a, 6b) can form the high-pressure side or the low-pressure side of the closed circuit. A high pressure accumulator device (20) can be connected with the respective high-pressure side hydraulic connection (6a, 6b) and, simultaneously, the respective low-pressure side hydraulic connection (6b, 6a) can be connected with a hydraulic balancing device (30). A valve device (50) is provided for this simultaneous connection. The valve device (50) is a hydraulically controlled shuttle valve device (51) connected to the two hydraulic connections (6a, 6b), the high pressure accumulator device (20) and the hydraulic balancing device (30).

Abstract: A hydrostatic drive system of a mobile machine includes a hydraulic work system and a hydraulic work pump that is driven by an internal combustion engine and, when operated as a pump, takes in hydraulic fluid with a suction side from a tank and, with a delivery side, delivers into a delivery line that leads to the hydraulic work system. A bypass valve is provided with which, when the hydraulic work pump is operated as a motor to start the shut-off internal combustion engine, the volume flow delivered by the hydraulic work pump operated as a motor to the delivery side is diverted to the tank. The bypass valve, in the motor operation to start the shut-off internal combustion engine, is actuated into an open position that connects the delivery side of the hydraulic work pump with the tank.

Abstract: A method for the production of a metal bearing layer (L) on a cylinder barrel (3) of a hydrostatic displacement machine (1), in particular of an axial piston machine, in which the metal bearing layer (L) is produced from a sintering powder in a sintering process. In a first production step, a dimensionally stable green compact (31) is produced from a sintering powder by a cold pressing process. In a second subsequent production step, the green compact (31) produced by the cold pressing process is sintered onto the cylinder barrel (3) in a sintering process.

Abstract: A hydrostatic axial piston machine (1) has a housing (2), a rotatable drive shaft (4) mounted in the housing (2) by a bearing device (5) that comprises at least one roller bearing (5a; 5b), a cylinder drum (7) having at least one piston bore (8), and a longitudinally displaceable piston (10) in each piston bore. A spray jet lubrication system (50) for the roller bearing (5a; 5b) includes at least one lubricant spray jet (51a; 51b) directed toward the area of an axial edge (30; 32) of an inner ring (5c; 5d) of the roller bearing (5a, 5b) with which the roller bodies of the roller bearing (5a, 5b) are in contact via an end surface.

Abstract: A hydrostatic positive displacement machine has a cylinder drum (4) located in a housing (9) and rotatable around an axis of rotation (2). During rotation of the cylinder drum (4), a piston bore (5) is placed in alternating communication with an inlet side (E) and an outlet side (A). The inlet side (E) and outlet side (A) comprise connections (21; 22) to a control plate (12). A reversing device (30) is located in a reversing area (25; 26) between the connections (21, 22) on the control plate (12). The reversing device (30) damps the pressure adjustment between a displacement chamber (V) and the pressure present in the connection (21; 22). The reversing device (30) includes at least two flow connections which are actuated simultaneously by the displacement chamber (V) as it moves along the reversing area (25; 26).

Abstract: A hydrostatic axial piston machine (1) utilizing a bent-axis construction has a driveshaft (4) with a drive flange (3) rotatable around an axis of rotation (Rt) inside a housing (2). A cylinder barrel (7) has pistons (10) fastened in an articulated manner to the drive flange (3). The drive flange (3) is supported on a housing-side slide face (101) by an axial bearing (100) in the form of a hydrostatically relieved sliding bearing (102) having a plurality of slippers (105). Each of the slippers (105) is mounted in an articulated manner in the drive flange (3) so that when the drive flange (3) rotates, a compensating force (FFR) acts on the slipper (105) which is in the opposite direction to the centrifugal force (FF) acting on the slipper (105). The point of application (AP) of the compensating force (FFR) on the slipper (105) is selected so that there is no tipping moment on the slipper (105) or to compensate for some or all of any tipping moment that does occur.

Abstract: A hydrostatic traction drive system of a mobile machine has a first hydraulic traction motor associated with a first vehicle side and a second hydraulic traction motor associated with a second vehicle side. The hydraulic traction motors are operated in an open circuit and are jointly supplied with hydraulic fluid by a single hydraulic pump. The first hydraulic traction motor is controlled by a first control valve and the second hydraulic traction motor is controlled by a second control valve. The first hydraulic traction motor and the second hydraulic traction motor are each variable displacement motors with an electrically variable displacement volume, and the first control valve and the second control valve are electrically actuatable control valves.

Abstract: A hydrostatic axial piston machine (1) utilizing a bent-axis construction has a drive shaft (4) with a drive flange (3) rotatable around an axis of rotation (Rt) inside a housing (2). A cylinder barrel (7) is located inside the housing (2) and is rotatable around an axis of rotation (RZ). A drive joint (30) is located between the drive shaft (4) and the cylinder barrel (7). The drive joint (30) has at least one drive body (M1; M2; M3; M4) in the form of a slider or a roller body which is supported in the drive shaft (4) and the cylinder barrel (7). A lubrication device (80) is provided for the drive joint (30) and supplies lubricant from a lubricant port (81) located on the housing (2) of the axial piston machine (1) to the drive bodies (M1; M2; M3; M4) for cooling and lubrication of the drive bodies (M1; M2; M3; M4).

Abstract: A bent-axis hydrostatic axial piston machine (1) has a drive shaft (4) with a drive flange (3) rotatable around an axis of rotation (Rt) and a cylinder drum (7) rotatable around an axis of rotation (Rz). The cylinder drum (7) has a plurality of piston bores (8) concentric to the axis of rotation (Rz) of the cylinder drum (7) and having longitudinally displaceable pistons (10) fastened in an articulated manner to the drive flange (3). Between the drive shaft (4) and the cylinder drum (7) there is a drive joint (30) (constant velocity joint) for rotationally synchronous rotation of the cylinder drum (7) and the drive shaft (4). The drive joint (30) and the cylinder drum (7) include a longitudinal bore (11) concentric to the axis of rotation (Rz) of the cylinder drum, through which bore (11) the drive shaft (4) extends such that in the vicinity of the drive shaft (4) there is a torque transfer to a cylinder-drum-side end of the axial piston machine (1).

Abstract: A hydrostatic variable displacement pump (2) has a displacement volume set by an electro-hydraulic control device (10) provided with a safety function. In a fault scenario, the variable displacement pump (2) is set to a neutral position. The electro-hydraulic control device (10) has a single electro-hydraulic setpoint encoder (30) to specify the setpoint of the displacement volume of the variable displacement pump (2) and an electrically actuatable valve device (35) connected in series downstream of the setpoint encoder (30), by which the direction of displacement of the variable displacement pump (2) is controlled and which is provided with the safety function.

Abstract: A hydrostatic axial piston machine (1) has a cylinder barrel (7) with a plurality of piston bores having pistons (10) fastened in an articulated manner to a drive flange (3). For articulated fastening of the pistons (10) to the drive flange (3), ball joints (20) are provided that are formed by a spherical cap-shaped receptacle socket (3a) in an end surface (3b) of the drive flange (3) and a ball head (10a) that is operatively connected with the piston (10). The receptacle sockets (3a) are each in the form of hemispheres that extend to the ball equator, and on one end surface (3b) of the drive flange (3), in the vicinity of the receptacle sockets (3a), there is a retaining web (30) that extends beyond the ball equator of the hemisphere to grip the ball head (10a) at an angle of greater than 180°.

Abstract: A hydrostatic drive system (1) has a hydrostatic pump (3) driven by a drive motor (2) and connected in a closed circuit with a hydrostatic motor (4). The hydrostatic motor (4) drives a consumer (5) and the closed circuit is formed by a first hydraulic connection (6a) and a second hydraulic connection (6b). A hydrostatic accumulator (30) can be connected with at least one of the two hydraulic connections (6a, 6b). A hydrostatic drive unit is located in an accumulator flow path (21) between one of the two hydraulic connections (6a, 6b) and the hydrostatic accumulator (30) and an additional hydrostatic drive unit is located in a tank flow path (22) between the other of the two hydraulic connections (6a, 6b) and a tank (17). The hydrostatic drive unit and the additional hydrostatic drive unit are a hydrostatic dual-flow double drive unit (20) provided in the accumulator flow path (21) and in the tank flow path (22).

Abstract: A hydrostatic drive system (1) with a hydrostatic pump (3) driven by a drive motor (2) and connected in a closed circuit with a hydrostatic motor (4). The hydrostatic motor (4) is connected with a consumer (5). The closed circuit is formed by a first hydraulic connection (6a) and a second hydraulic connection (6b). A pressure accumulator device (30) can be connected with the two hydraulic connections (6a, 6b) for the storage of energy and the output of energy. The pressure accumulator device (30) is a double piston accumulator (31) having a high-pressure-side pressure chamber (32) and a low-pressure-side pressure chamber (33). The high-pressure-side pressure chamber (32) can be connected with one of the two hydraulic connections (6a, 6b) of the closed circuit and simultaneously the low-pressure-side pressure chamber (33) can be connected with the respective other hydraulic connection (6b, 6a) of the closed circuit.

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 hydrostatic hybrid drive device (H) includes only one hydrostatic displacement machine (1) operated in an open circuit. A delivery line (2) leads to a high pressure accumulator device (3). A shutoff valve (5) controls flow to the high pressure accumulator device (3). A branch line (6) is connected with a low pressure accumulator device (7). A shutoff valve (9) in the intake line (8) shuts off flow to the low pressure accumulator device (7). A discharge line (10) is connected between the intake side (S) of the displacement machine (1) and the shutoff valve (9). A valve device (15) controls the discharge line (10) and the branch line (6).

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 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 bent-axis hydrostatic axial piston machine (1) has a drive shaft (4) rotatable around an axis of rotation (Rt) and having a drive flange (3). A cylinder drum (7) is rotatable around an axis of rotation (Rz). The cylinder drum (7) includes a plurality of piston bores (8) concentric to the axis of rotation (Rz) of the cylinder drum (7) and in each of which piston bores (8) there is a longitudinally displaceable piston (10). The pistons (10) are fastened in an articulated manner to the drive flange (3). Between the drive shaft (4) and the cylinder drum (7) there is a constant velocity driving joint (30) in the form of a cone-beam semi-roller joint (31).

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).