Abstract: A drive device comprises a first switchgear (9) and a second switchgear (11) which can be actuated respectively hydraulic pressure in an opening direction and via spring force in a closing direction, and which are provided with a device (26) by which the first switchgear (9) and the second switchgear (11) are to be actuated in the opening direction when the switchgears are actuated in the closing direction.

Abstract: A shiftable transmission in which at least two clutches (2, 7) actuated in closing direction by spring force and in opening direction by the exertion of pressure are arranged, wherein output of the transmission is stopped by unpressurized shifting of both actuation devices (9, 13) thereby closing both clutches (2, 7). When pressure is exerted upon the second actuation device (13), the actuation force of the first actuation device (9) is composed of a spring force of the first actuation device (9) and a hydraulic force from the pressurization of the second actuation device (13). The clutch belonging to the first actuation device can thus be impinged upon with different forces depending on whether or not the second actuation device is impinged upon with pressure.

Abstract: A drive device comprises a first switchgear (9) and a second switchgear (11) which can be actuated respectively hydraulic pressure in an opening direction and via spring force in a closing direction, and which are provided with a device (26) by which the first switchgear (9) and the second switchgear (11) are to be actuated in the opening direction when the switchgears are actuated in the closing direction.

Abstract: A shiftable transmission in which at least two clutches (2, 7) actuated in closing direction by spring force and in opening direction by the exertion of pressure are arranged, wherein output of the transmission is stopped by unpressurized shifting of both actuation devices (9, 13) thereby closing both clutches (2, 7). When pressure is exerted upon the second actuation device (13), the actuation force of the first actuation device (9) is composed of a spring force of the first actuation device (9) and a hydraulic force from the pressurization of the second actuation device (13). The clutch belonging to the first actuation device can thus be impinged upon with different forces depending on whether or not the second actuation device is impinged upon with pressure.

Abstract: A powershift reversing transmission (1) having a hydrodynamic torque converter and at least two clutches (17, 18) for shifting to the forward and reverse driving directions. The clutches are designed as negative clutches. A reservoir (33), from which pressurized medium flows through an aperture (37), is provided to modulate the pressure when reversing the transmission. A throttle (39), with a variable cross section, is provided for inching. A back pressure may be applied to the clutches (17 or 18) through the throttle (39). This reversing transmission is particularly useful for driving lift trucks or as an entry unit for a multi-speed reversing transmission.

Abstract: The invention relates to a drive system for a motor vehicle, in particular for a construction machine. A hydrostatic transmission unit comprising a variable displacement pump (25), a variable displacement motor (1) and a feed pump (26), is connected downstream of a diesel motor (24). In order to change gears in a powershiftable planetary transmission unit (2), gear-shift valves (34, 40) are provided. A brake (14) can be operated by a brake switching valve (30). The brake switching valve (30) is connected via line sections (33, 39) to the gearshift valves. When the brake switching valve (30) is in one switching position, a reservoir (37) is filled with hydraulic fluid. When in another switching position, a connection is made between the reservoir and a brake pressure chamber (20). During normal running of the machine, the reservoir is filled constantly with hydraulic fluid. When the brakes are operated, an adjustable residual pressure always acts on the brake. The brake is designed for dynamic deceleration.

Abstract: A drive device specially used in mobile excavators, wheeled loaders and similar work machines contains a power-shiftable transmission (4) designed as planetary transmission and driven by a hydraulic motor (3). The transmission (4) preferably has two speed levels which are alternatively engageable and disengageable via hydraulically shiftable friction clutches (12, 13). Both friction clutches (12, 13) are designed as spring-accumulator clutches and are controllable by oil pressure generated by an oil pump (21) and both friction clutches (12, 13) are controlled via a gear-shift valve (23). One of the two friction clutches (13) is designed as brake and has a static, leakage-oil-free oil supply. When the oil pressure generated by the oil pump (21) falls below a specific value, the gear-shift valve (23) is engaged into its 2nd-gear position in which only the brake is actuatable with oil pressure.

Abstract: An engine-rpm-dependent arrest device to prevent non-permitted down shifts in motor vehicle transmissions containing a pilot valve (1) and a control valve (2), both having two shift positions. One shift position of the control valve (2) is engaged by the pressure acting upon a piston surface (36) of the control-valve piston (31) and exceeding a given value of an engine-rpm-dependent low-pressure pump (20). The control valve (2) is exclusively in contact with the pressure medium conveyed by the low-pressure pump (20) and controls the large end surface (40) and the annular surface (41) of a pilot-valve piston (38) designed as stepped piston. If when the high gear is engaged and the engine rpm is above a certain limit value, the gear-shift valve (7) is moved to its position for low gear, then an actuation of the actuation device (15) for the low gear is prevented via the pilot valve (1).

Abstract: A driving mechanism, specially for mobile excavators and similar construction machines, having a power-shiftable two-gear transmission (4) constructed as planetary gear and driven by a hydromotor, includes two speed levels alternatively engageable and disengageable via hydraulically shiftable friction clutches (9, 10). Both friction clutches (9, 10) are designed as spring accumulator clutches controllable by oil pressure. Both friction clutches (9, 10) are radially telescoped and are to be used both for shifting the gears and as parking brake and auxiliary service brake.

Abstract: A driving mechanism, specially for use as tractor motor or servomotor, is made specially compact and makes possible the use of a simple, flat main wheel such as a sprocket. The compact construction is obtained by a few structural parts mostly made of one piece such as a hollow wheel for torque delivery and assembly of the main wheel driven by the mechanism and a hub support for carrying the hollow wheel and gear cap with simultaneous support for part of the gearing. A sound-insulated hydromotor is accommodated in the interior of the driving mechanism, a safety brake surrounds part of the hydromotor so as to result in a space-saving construction. Since the driving mechanism is axially not longer than the width of a tractor chain, it remains well protected when it serves as driving motor in a caterpillar vehicle.

Abstract: Each wheel of a road roller is provided with a drive which has a hydraulic motor with a radial output shaft coupled to the drive shaft of the wheel by bevel gearing. At one side of the housing containing the bevel gearing and the hydraulic motor, a brake is provided for the drive shaft whose opposite end is connected by a toothed coupling to the sun gear shaft of a planetary gearing transmission in a second housing disposed at least in part within the wheel. A flange of this transmission is connected to the planet carriers and to the wheel to rotate the latter.

Abstract: In a cement-mixer truck having a mixing drum rotated via a step-up transmission by a hydrostatic motor in turn energized by a power pump driven by the vehicle engine, the motor is disposed in a chamber at least partially filled with coolant replenished by leakage from the power pump and the motor and by oil from a valve housing supplied via a pressure-regulating and a bleeding valve respectively tapping high-pressure and low-pressure pumping conduits of a hydraulic circuit. The motor coolant chamber is surrounded by an oil reservoir connected at an output via an internal filter and a second engine-driven pump to the hydraulic circuit for feeding oil thereto and at an input via a heat exchanger to the motor chamber for drawing hot fluid from the motor bath, the reservoir serving in part to reduce noise from the hydraulic motor. A ventilating fan at the heat exchanger and a water pump are driven directly by the same shaft that is connected to the step-up transmission.

Abstract: A wheel-mounted drive system usable for a sprocket wheel of a chain-drive vehicle has a nonrotatable two-part housing adapted to be mounted directly and substantially immovably on the vehicle frame. A hydraulic motor is mounted in one part of this housing and has a motor output extending through the other part of the housing which contains a transmission whose input is connected to the motor output and whose output is directly connected to the drive wheel and to a brake. A bearing rotatably mounts the transmission output directly on the housing. The brake can be pressurized through axial passages extending through the main shaft of the motor. The transmission includes planetary gearing, and the motor, transmission, and output member are all rotatable about the same central axis.