The invention relates to a press for extruding metal material. The press comprises a hydraulic oil circuit for controlling one or more extrusion pistons movable within corresponding cylinders. Such a circuit comprises a fixed displacement, circulation pump operated by an electric motor with variable rotation speed. The hydraulic circuit comprises a main line and a branch line, along which a shutoff element is arranged. The hydraulic circuit comprises a hydraulic control unit comprising a pilot valve arranged along a pilot line provided with a first segment communicating with the main line and a second discharging segment. Said hydraulic unit is provided to move the shutoff element between an opening position and a closing position of the branch line according to the difference between the oil pressure upstream of the shutoff element and that in the first segment of said pilot line. The hydraulic circuit further comprises a control element which, in an activation condition, and as a result of the activation of said pilot valve, determines a gradual increase of the pressure in the first segment of said pilot line and a corresponding gradual closing movement of said shutoff element causing a consequent gradual increase of the thrust on the piston until the reference speed is reached.

Provided is a construction machine on which a hydraulic closed circuit for driving a single rod-type hydraulic cylinder and a swing hydraulic motor is mounted and that has good swing deceleration responsiveness. In this construction machine that drives each of a single rod-type hydraulic cylinder and a swing hydraulic motor in a closed circuit, a minimum passage area from a second flushing valve to a tank in a case the second flushing valve is fully open is smaller than a minimum passage area from a first flushing valve to the tank in a case the first flushing valve is fully open.

A bi-directional pump connected to a motor by a pair of supply/discharge lines; a regulator changes the bi-directional pump tilting angle; and a controller controls the regulator based on a turning signal outputted from a turning operation valve. At the turning acceleration, at which the signal increases, the controller calculates a motor flow rate passing through the motor and an instruction flow rate determined based on the turning signal. If the instruction flow rate is greater than a reference flow rate obtained by adding a predetermined value to the motor flow rate, the controller controls the regulator so the bi-directional pump tilting angle is adjusted to a tilting angle realizing the reference flow rate. If the instruction flow rate is not greater than the reference flow rate, the controller controls the regulator so the bi-directional pump tilting angle is adjusted to a tilting angle realizing the instruction flow rate.

An actuator controller for actuating an actuator which can be operated fluidically, having a feed line for an inflow of the working fluid to an actuator connector and having a discharge line for an outflow of the working fluid to a fluid outlet, wherein the feed line is assigned a feed line valve and the discharge line is assigned a discharge valve, which valves are configured in each case to influence a volumetric fluid flow at the actuator connector, and having a control device for actuation of the feed line valve and the discharge valve. A throughflow sensor is arranged in a line section between the discharge valve and the fluid outlet, which throughflow sensor is configured for determining a volumetric fluid flow in the discharge line and for providing a throughflow signal.

A drive control system of a hydraulic excavator includes a control device. When accelerating a turning body to a target turning speed, the drive control device controls an operation of the electric motor driving device such that the electric motor outputs high efficiency torque by which a highest electric power efficiency is obtained at the target turning speed. The control device controls an operation of an oil pressure supply device such that residual torque obtained by subtracting the high efficiency torque from target torque is output from an oil-pressure motor.

A trajectory planning unit for providing a trajectory as a command variable for a control unit for position control of an actuator member of an actuator, wherein the trajectory planning unit is adapted to provide the trajectory on the basis of a target position curve and to limit the trajectory according to at least one limit value comprising a velocity limit value, an acceleration limit value, a braking acceleration limit value and/or a jerk limit value. The trajectory planning unit is adapted to provide the trajectory according to at least one specification value which can be specified, the specification value including an initial velocity value, a final velocity value, an initial acceleration value and/or a final acceleration value.

A main flow path that introduces high-pressure air to an air cylinder, or discharges exhaust air therefrom, includes a sub flow path provided alongside the main flow path; an exhaust flow rate adjustment unit that suppresses the operation speed of the air cylinder by adjusting the flow rate of the exhaust air flowing through the sub flow path; and a switching valve that is connected between the air cylinder, the main flow path and the sub flow path, and that connects the main flow path and the sub flow path to the air cylinder in a switching manner. The switching valve is constituted by a spool valve.

A gas cylinder includes supply passages for supplying, to an accommodation chamber, a part of gas supplied to a second port. When the pressure in a first pressure chamber is equal to or lower than a prescribed pressure, a valve element closes a discharge flow passage by the biasing force of a spring member and the pressure in the accommodation chamber. When the pressure in the first pressure chamber exceeds the prescribed pressure, the valve element is moved by the pressure in the first pressure chamber, against the biasing force and the pressure in the accommodation chamber, to thereby open the discharge flow passage.

A hydraulic circuit is disclosed. The hydraulic circuit may include a hydrostatic pump to provide, at a flow rate, a fluid to a hydraulic motor, wherein the hydrostatic pump has a displacement, and wherein the hydraulic motor drives a swinging element; a swing circuit pressure sensor to sense a circuit pressure of the hydraulic circuit; a pilot pressure actuator to control, based on a supply pressure, the displacement of the hydrostatic pump; a pilot pressure override valve to control the supply pressure; and a controller configured to adjust, based on sensed signals and with the pilot pressure override valve, the supply pressure, wherein the sensed signals include: a circuit pressure signal based on the circuit pressure sensed by the swing circuit pressure sensor; and a sensed swing speed signal based on a swing speed of the swinging element sensed by one or more machine sensors.

A compressed air provision device (2) for aerating a first pressure chamber (10) of a pneumatic actuator in order to actuate an actuator element (11) of the pneumatic actuator (3) in accordance with an actuation specification, in particular a position, movement, pressure and/or force specification. The compressed air provision device (2) is configured to calculate an aeration period (bd) and to aerate the first pressure chamber (10) in accordance with the calculated aeration period (bd) in order to bring about actuation of the actuator element (11) in accordance with the actuation specification.