The invention relates to a device comprising a first hydraulic apparatus (M1) and a second hydraulic apparatus (M2), the two motors (M1, M2) being connected by a first line (11) and a second line (12) enabling the admission or discharge of the oil in said motors (M1, M2), a booster pump (30), arranged between a tank and a booster line, the booster line communicating with at least one of said lines (11, 12), characterized in that the pump (30) is configured to be able to suck oil into the booster line in order to allow the decompression of said first and second lines (11, 12). The invention also relates to a method for evacuating a device of the type described above, in which the booster pump (30) is activated in suction mode in the booster line to enable the disengagement of the machines (M1, M2).

A hydrostatic valve arrangement for flushing pressure medium from a working line of a hydraulic circuit includes a flushing valve with a first flushing connection for connecting to a first working line and an output connection for connecting to a pressure medium sink. The arrangement also includes a pressure valve arranged in a pressure medium flow path of the arrangement from the output connection in the direction of the pressure medium sink. The pressure valve has a valve body on which a force equilibrium is formed. The force equilibrium includes a pressure equivalent that acts on the valve body in a direction that blocks the pressure medium flow path and an opening pressure that acts in a direction that opens the pressure medium flow path and is dependent on the pressure at the output connection. The arrangement further includes an adjusting device for shifting the force equilibrium.

A hydrostatic valve arrangement for flushing pressure medium from a working line of a hydraulic circuit includes a flushing valve with a first flushing connection for connecting to a first working line and an output connection for connecting to a pressure medium sink. The arrangement also includes a pressure valve arranged in a pressure medium flow path of the arrangement from the output connection in the direction of the pressure medium sink. The pressure valve has a valve body on which a force equilibrium is formed. The force equilibrium includes a pressure equivalent that acts on the valve body in a direction that blocks the pressure medium flow path and an opening pressure that acts in a direction that opens the pressure medium flow path and is dependent on the pressure at the output connection. The arrangement further includes an adjusting device for shifting the force equilibrium.

The invention relates to a hydraulic circuit provided with at least one hydraulic power machine (2, 4) connected to a low-pressure circuit (6) and to a high-pressure circuit (10) transmitting said power, wherein the machine is provided with a drain which allows internal leaks in the casing thereof to flow towards a low-pressure accumulator (8) or a vessel at atmospheric pressure, said circuit comprising an intake pipe (30) connecting the low-pressure circuit (6) to the casing of the machine, and an outlet pipe (36) forming the drain receiving the flow from the intake pipe in order to guide same towards the vessel (8), including a heat exchanger (42) and a filter (44) forming the fluid treatment elements for the entire hydraulic circuit, said circuit also comprising a means for monitoring the flow (40) in the intake and outlet pipes.

The invention relates to a hydraulic circuit provided with at least one hydraulic power machine (2, 4) connected to a low-pressure circuit (6) and to a high-pressure circuit (10) transmitting said power, wherein the machine is provided with a drain which allows internal leaks in the casing thereof to flow towards a low-pressure accumulator (8) or a vessel at atmospheric pressure, said circuit comprising an intake pipe (30) connecting the low-pressure circuit (6) to the casing of the machine, and an outlet pipe (36) forming the drain receiving the flow from the intake pipe in order to guide same towards the vessel (8), including a heat exchanger (42) and a filter (44) forming the fluid treatment elements for the entire hydraulic circuit, said circuit also comprising a means for monitoring the flow (40) in the intake and outlet pipes.

A loop flushing valve includes a valve body, a fluid passage plug, and a poppet. The valve body includes an internal shoulder and a bore. The fluid passage plug is disposed in the bore and includes a fluid passage in fluid communication with the bore and a system fluid passage. The poppet is captured between the internal shoulder and the fluid passage plug and extends through the valve body.

A valve housing includes a cylindrical valve bore with a high pressure inlet, a low pressure inlet and a discharge outlet. A first flushing valve spool is arranged elastically pre-stressed within the valve bore for enabling a fluid connection between the low pressure inlet and the discharge outlet. A shuttle valve spool is arranged elastically pre-stressed within the valve bore for enabling the fluid connection between the low pressure inlet and the discharge outlet. The first flushing valve spool is moveable into an open position if the fluid pressure at the low pressure inlet exceeds a first threshold value, and the shuttle valve spool is moveable into an open position for connecting the low pressure inlet with the discharge outlet, if the pressure difference between the high pressure inlet and the low pressure inlet exceeds a second threshold value.

A valve housing includes a cylindrical valve bore with a high pressure inlet, a low pressure inlet and a discharge outlet. A first flushing valve spool is arranged elastically pre-stressed within the valve bore for enabling a fluid connection between the low pressure inlet and the discharge outlet. A shuttle valve spool is arranged elastically pre-stressed within the valve bore for enabling the fluid connection between the low pressure inlet and the discharge outlet. The first flushing valve spool is moveable into an open position if the fluid pressure at the low pressure inlet exceeds a first threshold value, and the shuttle valve spool is moveable into an open position for connecting the low pressure inlet with the discharge outlet, if the pressure difference between the high pressure inlet and the low pressure inlet exceeds a second threshold value.

A transmission system includes a power take-off for driving an implement and a hydrostatic unit for transmitting power from the engine to the power take-off. The hydrostatic unit includes a first hydraulic power unit having a first connection line and a second connection line, and a second hydraulic power unit having a first connection line and a second connection line. The hydrostatic unit also includes a valve for connecting the first hydraulic power unit and the second hydraulic power unit, the valve being positionable at least in a first position a first position and in a second position.

A hydraulic driving device includes: a hydraulic motor configured to operate by flushing oil from a hydraulic pump through a high pressure oil passage and a low pressure oil passage; a low pressure selective valve configured to operate in accordance with differential pressure between the high pressure oil passage and the low pressure oil passage, and to discharge the oil in the low pressure oil passage inside a motor case; a tank oil passage configured to connect the inside of the motor case with an oil tank; and a choke throttle provided to the low pressure selective valve or to an oil passage lower than the low pressure selective valve.