A hydraulic system includes a first electric machine connected to a first hydraulic machine and a second electric machine connected to a second hydraulic machine. An output side of the second hydraulic machine is connected to an input side of the first hydraulic machine. A hydraulic consumer is hydraulically coupled to an output side of the first hydraulic machine via a supply line and is powered by the first hydraulic machine. A return line hydraulically couples the hydraulic consumer to an input side of the first hydraulic machine. The second hydraulic machine provides a flow of hydraulic fluid to the input side of the first hydraulic machine if a requested flow from the first hydraulic machine exceeds a flow of the return line and recuperates energy if the requested flow from the first hydraulic machine is lower than the flow of the return line.

A locking unit for the parking lock of an automatic transmission, for locking the movement of a piston which is movable by a drive and which can be acted on with hydraulic pressure.

A hydraulic system including a first cylinder conduit configured to couple to a cylinder, an auxiliary conduit configured to couple to a case drain conduit, and a pressure regulator coupled to the first cylinder conduit and to the auxiliary conduit. The pressure regulator may block fluid flow to the auxiliary conduit if a first fluid pressure is less than or equal to a threshold pressure and enable fluid flow if the first fluid pressure is greater than the threshold pressure. The hydraulic system further includes a supplemental conduit with a check valve that directs fluid from the auxiliary conduit to a reservoir. The check valve blocks fluid flow if a second fluid pressure is less than or equal to a third fluid pressure, and enables fluid flow if the second fluid pressure greater than the third fluid pressure.

Systems and methods are provided for controlling hydraulic valves. One embodiment is a method that includes blocking an orifice for a return line of a hydraulic valve via a flapper assembly, initiating a phase change in a Shape Memory Alloy (SMA) at the flapper assembly, and opening the orifice for the return line via the flapper assembly in response to the phase change.

An assembly system for components of a pressurized fluid supply system for an agricultural vehicle includes a body having at least one fluid duct connectable at one end to a pressurized fluid supply and having a socket at the other end. A detachable component such as an accumulator or oil filter is connectable in releasable mechanical engagement with the body to receive pressurized fluid from the at least one fluid duct. The engagement results from insertion of at least a portion of the component into the socket and rotation of the component to a locked position. The body has at least one discharge duct extending therethrough. In a partially rotated position of the component portion within the socket, the component remains mechanically attached to the body and the fluid duct and discharge duct are in fluidic connection, discharging accumulated pressure in the fluid duct.

A hydraulic system for a work vehicle has a first hydraulic circuit at a first nominal pressure and a second hydraulic circuit at a second nominal pressure different than the first nominal pressure. A dual-chamber hydraulic reservoir includes a first tank associated with the first hydraulic circuit and defining a first opening and a second tank associated with the second hydraulic circuit and defining a second opening. An exchange system has a particulate filter disposed within an exchange path between the first opening of the first tank and the second opening of the second tank. The exchange system is configured to resupply the first tank with hydraulic fluid from the second tank.

The invention relates to a hydraulic tank (10) for storing a hydraulic liquid, comprising a one-piece tank housing (12) which forms a plastic hollow body and is manufactured by a rotational moulding process, wherein the tank housing (12) comprises at least one connection opening (92, 94, 126) at which is arranged a connection element (100, 110, 132) that is releasably connectable to a hydraulic conduit. In order to enable the hydraulic tank to be more cost-effective to produce, the connection element (100, 110, 132) comprises a plastic body which is manufactured by an injection moulding process and is welded together with the tank housing (12). Furthermore, a method for manufacturing a hydraulic tank (10) is proposed.

A system for automatic calibration of an actuator, where the system has an actuator and a computer, and the computer further includes a PID controller. A sensor connected to the actuator transmits values representing the motion of the actuator to the input of the PID controller. The computer is programmed to compare the values representing the motion of the actuator to the output of the PID controller, thus outputting an error signal representing the difference between the output of the PID controller and the values representing the motion of the actuator. The computer stores this difference as a calibrated set point for the actuator when the difference is less than a predetermined amount. This calibrated set point is used to initialize the operation of a machine propelled by the actuator.

A failure detection apparatus for a hydraulic system, to a hydraulic, failure detection-capable system, and to a method of operating a failure detection apparatus. The failure detection apparatus comprises a monitoring and failure detection unit that receives first and second pressure values from first and second pressure sensors and comprises a failure detection unit that detects a failure of at least one hydraulically operated device when a 2-tuple of a plurality of 2-tuples is within a first and outside a second predetermined tolerance range of relative pressure values, and wherein the failure detection unit 260 detects a failure of the pump when a 2-tuple of the plurality of 2-tuples is outside the first predetermined tolerance range of relative pressure values.

Provided is an electrohydrostatic actuation system including an emergency shut-off circuit to be actuated stably with a simple configuration. The electrohydrostatic actuation system includes: a hydraulic cylinder (24) including a piston (25) to which a valve element is connected, a first chamber (24A), and a second chamber (24B); a hydraulic pump (21) configured to supply hydraulic fluid to the first chamber (24A) or the second chamber (24B); a servo motor (M) configured to drive the hydraulic pump (21); a shuttle valve (11) configured to establish communication to a downstream side under a state in which a hydraulic pressure generated by the hydraulic pump (21) is maintained; a solenoid valve (12) configured to receive the hydraulic pressure via the shuttle valve (11) as a pilot pressure; and a logic valve (13) including a first port configured to receive the pilot pressure from the solenoid valve (12), and a second port to be communicated to the first chamber (24A) of the hydraulic cylinder (24). When the solenoid valve (12) is brought to a de-energized state, the pilot pressure of the logic valve (13) is released, and the logic valve (13) causes the hydraulic fluid in the first chamber (24A) communicated to the second port to flow into the second chamber (24B) so that emergency shut-off of the valve element is achieved by a return spring (26).