The disclosure relates to a method of monitoring an electrohydrostatic actuator, wherein the electrohydrostatic actuator comprises a hydraulic pump drivable by an electric motor and a hydraulic activator drivable by means of the hydraulic pump to move a component, in particular an aircraft part. The method include detecting the instantaneous speed of the electric motor; detecting an instantaneous position of the activator; detecting a parameter that relates to an instantaneous operating point of the electrohydrostatic actuator; determining a state variable relating to an efficiency of the electrohydrostatic actuator on the basis of at least the detected speed and the detected position in dependence on the detected parameter; and determining a state of the electrohydrostatic actuator on the basis of the currently determined value.

A system and method is provided for monitoring a hydraulic power system having at least one light emitter and a button. The method includes powering on the hydraulic power system, receiving an actuation at the button and detecting a release of the button after a first time interval, and entering a diagnostic state. The method further includes retrieving a code and displaying the code by turning on the emitter in a first pattern. In some embodiments, a system and method is provided for regulating a temperature of a hydraulic power system. In some embodiments, a system and method is provided for controlling operation of a hydraulic torque wrench.

A hydraulic system for a machine includes an implement pump, a valve, and an implement valve subsystem. The implement pump includes a load sensing control, and the valve controls the flow of hydraulic fluid to the implement pump. The implement valve subsystem includes one or more implement control subsystems to control movement of an implement. The valve is an electrohydraulic proportional relief valve and includes a solenoid configured to adjust the pressure of hydraulic fluid delivered to the implement pump proportionally to a current delivered through the solenoid.

A landing gear lifting/lowering EHA system includes: a hydraulic actuator configured to lift and lower the leg of an aircraft; at least one electrically operated hydraulic pump; a hydraulic path; a pressure sensor attached to the hydraulic actuator or the hydraulic path and configured to output a measurement signal corresponding to hydraulic pressure; and a controller configured to output a control signal to the electrically operated hydraulic pump, wherein, when a state in which the hydraulic pressure exceeds a set pressure continues for a set time, the control unit stops the electrically operated hydraulic pump in operation and resumes the operation of the electrically operated hydraulic pump after the hydraulic pressure drops to or below a second set pressure after the electrically operated hydraulic pump is stopped.

Provided is a driving apparatus capable of effectively preventing impact at the stroke end in the hydraulic cylinder. The driving apparatus includes a hydraulic pump, a cylinder control valve, an operation member, a drive command input unit inputting a cylinder drive command corresponding to a cylinder operation applied to the operation member to the cylinder control valve, a cylinder stroke detection unit, a cylinder drive command restriction unit restricting the cylinder drive command in response to the cylinder stroke to stop a piston of a hydraulic cylinder before the stroke end.

A hydraulic excavator 1 includes an engine 16, a main hydraulic pump 17 driven by the engine 16, a plurality of hydraulic actuators driven with pressure oil discharged from the main hydraulic pump 17, a plurality of flow rate control valves adapted to control the flow rate of pressure oil to be supplied from the main hydraulic pump 17 to the respective hydraulic actuators, a pilot hydraulic pump 18 adapted to supply pressure oil for driving the flow rate control valves, and a controller 15 configured to control the discharge flow rate of the pilot hydraulic pump 18. The controller 15 controls the discharge flow rate of the pilot hydraulic pump 18 such that it becomes equal to the sum of requested pilot flow rates determined in accordance with control commands for the respective flow rate control valves and a preset standby flow rate.

An HST circuit has a hydraulic pump that converts a drive force of an engine into energy of oil, and a hydraulic motor that converts the energy of the oil converted by the hydraulic pump into drive energy. Pressure sensors detect a pressure of the oil within the HST circuit. A variable charge pump replenishes the oil into the HST circuit. A controller controls a capacity of the variable charge pump based on the pressure of the oil within the HST circuit detected by the pressure sensors.

Provided is a driving apparatus capable of effectively preventing impact at the stroke end in the hydraulic cylinder. The driving apparatus includes a hydraulic pump, a cylinder control valve, an operation member, a drive command input unit inputting a cylinder drive command corresponding to a cylinder operation applied to the operation member to the cylinder control valve, a cylinder stroke detection unit, a cylinder drive command restriction unit restricting the cylinder drive command in response to the cylinder stroke to stop a piston of a hydraulic cylinder before the stroke end.

The disclosure relates to a method for operating a hydraulic drive which comprises a hydraulic consumer with a positionable piston in a cylinder which is connected to a tank at one connection via a pump of variable rotational speed and at another connection via a proportional valve, wherein a position of the piston is controlled using a model-based control in which a rotational speed of the pump is used as a manipulated variable and in which a position of the proportional valve is preset.

An HST circuit has a hydraulic pump that converts a drive force of an engine into energy of oil, and a hydraulic motor that converts the energy of the oil converted by the hydraulic pump into drive energy. Pressure sensors detect a pressure of the oil within the HST circuit. A variable charge pump replenishes the oil into the HST circuit. A controller controls a capacity of the variable charge pump based on the pressure of the oil within the HST circuit detected by the pressure sensors.