A power system for a working machine includes a transmission for driving the working machine, the transmission including a continuously variable gear box having a gear unit and a hydraulic variator unit; a work hydraulic circuit for controlling at least one hydraulic actuator of the working machine; wherein the hydraulic variator unit is hydraulically connected to the work hydraulic circuit to hydraulically transfer energy from the hydraulic variator unit to the work hydraulic circuit.

In a self-propelled construction machine (1), in particular road milling machine, comprising a machine frame (8), at least three travelling devices (12, 16), wherein at least one of the three travelling devices (12, 16) is realized as a pivotable travelling device (16) so that said travelling device (16) is pivotable about at least one vertical pivoting axis in relation to the machine frame (8) between a first pivoted-in and at least one second pivoted-out position, at least one working device (20), in particular a milling drum, for working the ground pavement (3), at least one hydraulic drive system (70) for driving at least two travelling devices (12, 16), wherein at least one of the at least two driven travelling devices is the pivotable travelling device (16), wherein the hydraulic drive system (70) comprises at least one hydraulic pump (78), it is provided for the following features to be achieved: the hydraulic drive system (70) comprises one each hydraulic variable displacement motor (72) for driving the driven travelling devices (12) with the exception of the at least one pivotable travelling device (16), wherein the hydraulic drive system (70) comprises a hydraulic fixed displacement motor (74) for driving the at least one pivotable travelling device (16).

A hydraulic arrangement. The hydraulic arrangement has multiple hydraulic units, the control units of which are connected, in particular in series, via a data connection. The control units are preferably designed to control selectively only hydraulic cylinders directly associated with said units, or also indirectly control, via the data connection and the control unit of an additional hydraulic unit, the hydraulic cylinders associated with said additional hydraulic unit. A climbing formwork having at least one climbing unit, in particular multiple climbing units. The hydraulic units can be linked via the data connection such that synchronous lifting and/or lowering of all climbing units can be or is achieved. The hydraulic units are preferably connected in a master-slave arrangement or are preferably controlled in a master-slave mode. Also preferably, the hydraulic units are designed to switch from the master-slave mode to the stand-alone mode.

A milling machine includes a cutting rotor accommodated in a rotor enclosure having side plates that are vertically adjustable with respect to a machine frame. To adjust the vertical elevation of the side plates, a plurality of sensors is mounted on the machine frame and associated with an electronic controller that measures and processes the vertical distance between the side plates and work surface. The electronic controller operates a hydraulic system to adjust the vertical distance between the side plates and the work surface. To accommodate changes in work surface topography, the hydraulic system includes a float circuit with an accumulator.

A hydraulic fluid system is disclosed and that utilizes a hydraulic motor or gear pump and a magneto-rheological fluid (MRF) brake that is interconnected with an output of the hydraulic motor. The MRF brake may utilize a rotatable rotor that is disposed within a magneto-rheological fluid and that is interconnected with an output (e.g., a rotatable output shaft) of the hydraulic motor. An electrical control signal may be provided to the MRF brake (e.g., to a magnetic coil) to adjust the viscosity of the magneto-rheological fluid, and thereby a braking torque exerted on the output of the hydraulic motor.

A hydraulic fluid system is disclosed herein. The hydraulic fluid system includes a hydraulic motor including an output shaft, a reduction gear box having a first side and an opposing second side, the reduction gear box being coupled to the output shaft at the first side and coupled to a reduction shaft at the second side, and a magneto-rheological fluid brake (MRF) brake coupled to the reduction shaft.

A hydraulic machine (1) has a working section (6) and a fluid control section (28). The fluid control section includes a spool (3) that is rotatable in a cylindrical bore (30) about an axis (4). A distributor plate (18) extends intermediate of the control section and the working section. The spool includes an axial recess (10) which is axially bounded by a radially extending annular wall (44). A front face (48) of the annular wall rotates in abutting engagement with a plate face contact area (50) of the distributor plate. Hydraulic fluid flows through at least one groove (52) that extends radially and circumferentially across the abutting areas of the spool and the distributor plate to provide lubrication and heat absorption.

A hydraulic drive device for an industrial vehicle includes a variable displacement pump, a displacement control valve, a power steering cylinder, a power steering valve, a loading cylinder, a loading valve, a hydraulic oil passage, and a pilot line. The displacement control valve controls the variable displacement pump to increase displacement of the variable displacement pump when differential pressure between discharge pressure of hydraulic oil discharged from the variable displacement pump and pilot pressure generated in the pilot line is smaller than a predetermined set pressure. A spool of the loading valve is provided with a groove portion that forms a communication passage that makes communication between the hydraulic oil passage and the pilot line at a neutral position of the loading valve when the power steering valve is located in a neutral position.

A hydraulic fluid system is disclosed and that utilizes a hydraulic motor or gear pump and a magneto-rheological fluid (MRF) brake that is interconnected with an output of the hydraulic motor. The MRF brake may utilize a rotatable rotor that is disposed within a magneto-rheological fluid and that is interconnected with an output (e.g., a rotatable output shaft) of the hydraulic motor. An electrical control signal may be provided to the MRF brake (e.g., to a magnetic coil) to adjust the viscosity of the magneto-rheological fluid, and thereby a braking torque exerted on the output of the hydraulic motor.

A control system includes: an engine; a first hydraulic pump and a second hydraulic pump driven by the engine; a switching device provided in a flow path that connects the first hydraulic pump to the second hydraulic pump, and configured to perform switching between a merged state in which the flow path is opened and a separated state in which the flow path is closed; a first hydraulic actuator to which hydraulic fluid discharged from the first hydraulic pump is supplied in the separated state; a second hydraulic actuator to which hydraulic fluid discharged from the second hydraulic pump is supplied in the separated state; a determining unit configured to determine whether output of the engine is limited; and a merging-separating control unit configured to control the switching device so as to perform switching to the merged state when the determining unit determines that output of the engine is limited.