Abstract: The invention relates to a drive train (1) for a hydraulic drive where a friction coupling (3) is arranged between a hydraulic machine (2) and a consumer (5). The coupling (3) has two parts (20A, 20B) which are displaceable towards each other in the axial direction (18) and are connected to the hydraulic machine (2) or to the consumer (5). Hydraulic fluid is introduced by means of a pressure line (28) into a pressure chamber (27) formed between the parts (20A, 20B), as a result of which the complementarily formed friction surfaces (9A, 9B) become frictionally locked together and a torque is able to be transmitted between the hydraulic machine (2) and the consumer (5). The friction surfaces (9A, 9B) are each fixedly connected at least radially to the shaft of the hydraulic machine (2) or of the consumer (5).

Abstract: The invention relates to a drive train (1) for a hydraulic drive where a friction coupling (3) is arranged between a hydraulic machine (2) and a consumer (5). The coupling (3) has two parts (20A, 20B) which are displaceable towards each other in the axial direction (18) and are connected to the hydraulic machine (2) or to the consumer (5). Hydraulic fluid is introduced by means of a pressure line (28) into a pressure chamber (27) formed between the parts (20A, 20B), as a result of which the complementarily formed friction surfaces (9A, 9B) become frictionally locked together and a torque is able to be transmitted between the hydraulic machine (2) and the consumer (5). The friction surfaces (9A, 9B) are each fixedly connected at least radially to the shaft of the hydraulic machine (2) or of the consumer (5).

Abstract: A hydraulic spool valve is provided in which two inlet bores and an outlet bore lead into a housing. A spool-valve piston which is under the influence of compression springs on both sides can be displaced longitudinally in the housing. When a difference in pressure of the hydraulic fluid in the inlet bores occurs, the inlet bore which conducts the lower pressure in each case is connected to the outlet bore. The two compression springs are pre-stressed and have an additional expansion path. During the displacement of the spool-valve piston from a neutral central position into an extended intermediate position, the two compression springs therefore remain in operative connection with the spool-valve piston, in which case the spring forces counterbalance each other until the intermediate position is reached.

Abstract: A hydraulic spool valve is provided in which two inlet bores and an outlet bore lead into a housing. A spool-valve piston which is under the influence of compression springs on both sides can be displaced longitudinally in the housing. When a difference in pressure of the hydraulic fluid in the inlet bores occurs, the inlet bore which conducts the lower pressure in each case is connected to the outlet bore. The two compression springs are pre-stressed and have an additional expansion path. During the displacement of the spool-valve piston from a neutral central position into an extended intermediate position, the two compression springs therefore remain in operative connection with the spool-valve piston, in which case the spring forces counterbalance each other until the intermediate position is reached.

Abstract: A hydraulic motor (1), has an output shaft (3), a block cylinder (6), and high-pressure pistons (7) guided therein, and a block cylinder spring (9) and a valve plate (5). The block cylinder (6) exerts a contact-pressure force on the valve plate (5) by way of the charging pressure of the hydraulic oil in the block cylinder (6) and of the spring force of the block-cylinder spring (9). The contact-pressure force is counter-acted, when the hydraulic motor (1) is at a standstill, by a hydraulic pressure field which is built up on a surface (13) between the block cylinder (6) and the valve plate (5) via a valve device (12).

Abstract: A hydraulic motor (2) with a braking device (8), is acted upon by means of a control fluid via a brake release line (6). The brake release line (6) is used to allow a continuous flushing flow of control fluid through the hydraulic motor at the same time as the release of the brake. The braking device (8) is connected to the casing of the hydraulic motor (2). An outlet opening (12) of the hydraulic motor (2) leads via a leakage-oil line (13) to the tank for the control fluid. In a hydraulic travel drive with a closed hydraulic circuit, the brake release line (6) can be connected to the shut-off device (4) for the servo adjustment system of the variable-displacement pump (1), and the leakage-oil line (13) of the hydraulic motor (2) can lead to the tank for the entire hydraulic fluid in the system.

Abstract: A hydraulic motor (1), has an output shaft (3), a block cylinder (6), and high-pressure pistons (7) guided therein, and a block cylinder spring (9) and a valve plate (5). The block cylinder (6) exerts a contact-pressure force on the valve plate (5) by way of the charging pressure of the hydraulic oil in the block cylinder (6) and of the spring force of the block-cylinder spring (9). The contact-pressure force is counter-acted, when the hydraulic motor (1) is at a standstill, by a hydraulic pressure field which is built up on a surface (13) between the block cylinder (6) and the valve plate (5) via a valve device (12).

Abstract: In a hydraulic vehicle drive which has a hydraulic circuit consisting of a variable displacement pump (2) and a hydraulic motor (10), the variable displacement pump (2) is driven by a diesel engine (1). During the braking or overrunning operation of the vehicle, the hydraulic motor becomes the pump and drives the variable displacement pump (2) which acts as a motor on the diesel engine (1) and attempts to accelerate the latter. The braking effect which is intended and obtained thereby involves the risk of the diesel engine (1) reaching impermissibly high rotational speeds. The braking therefore takes place in a controlled manner by a sequence valve (16) being arranged in the line (12) between the hydraulic motor (10) and the variable displacement pump (2). The sequence valve acts on the pivot angle of the variable displacement pump (2) via the pump bypass line (12B).

Abstract: A hydraulic motor (2) with a braking device (8), is acted upon by means of a control fluid via a brake release line (6). The brake release line (6) is used to allow a continuous flushing flow of control fluid through the hydraulic motor at the same time as the release of the brake. The braking device (8) is connected to the casing of the hydraulic motor (2). An outlet opening (12) of the hydraulic motor (2) leads via a leakage-oil line (13) to the tank for the control fluid. In a hydraulic travel drive with a closed hydraulic circuit, the brake release line (6) can be connected to the shut-off device (4) for the servo adjustment system of the variable-displacement pump (1), and the leakage-oil line (13) of the hydraulic motor (2) can lead to the tank for the entire hydraulic fluid in the system.

Abstract: A hydrostatic system includes a variable displacement hydraulic motor whose absorption volume is adjusted by a pressure regulator, depending on the rpms generated by the power source driving the system. The apparatus enables the variable displacement motor to fully utilize the drive power avaiable from the power source over a range of operating speeds.