A high-speed hydraulic forging press is disclosed. The high-speed hydraulic forging press includes a forging hammer, a movable beam, a main hydraulic cylinder, a single-rod elevation hydraulic cylinder, a plurality of main hydraulic pumps, a high-pressure energy accumulator, an intermediate-pressure energy accumulator, an oil tank, a programmable logic controller and a valve-regulation system. During a rolling process, when a rolling resistance applied to the forging hammer increases to cause pressure in the main hydraulic cylinder to reach a predetermined value, the programmable logic controller controls the valve-regulation system so that the high-pressure energy accumulator stops supplying the hydraulic oil to the main hydraulic cylinder, and that the hydraulic oil in the main hydraulic cylinder is supplied by at least one of the plurality of main hydraulic pumps. The high-speed hydraulic forging press exhibits remarkable advantages including a reasonable resource allocation, a simple structure, low equipment investment, and high energy utilization.

A pressure-measuring system, including a tube system having at least first and second pressure measuring devices, each including a pressure transducer membrane and a measuring chamber. A first flow regulation device with a perfusion tube section is positioned between the first pressure measuring device and a supply of fluid, and has a first tube clamp that acts on a tube section by squeezing. The system further includes at least one non-perfusion regulation device.

An actuator device includes two drive units for an actuator output element. The first drive unit has a first piston chamber and a first piston displaceable therein and also first hydraulic means for displacing the piston. The second drive unit has a second piston chamber and a second piston displaceable therein and also second hydraulic or pneumatic means for displacing the piston. The second piston is joined to the actuator output element for conjoint movement therewith and can be coupled to the first piston for thrust, so that the second piston is displaceable in an outward direction by the first piston. The first drive unit is configured for a larger thrust force than the second drive unit, while the second drive unit is designed for a greater stroke speed than the first drive unit.

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 are an efficient energy-saving return cylinder of a hydraulic press and a working method thereof. The efficient energy-saving return cylinder of a hydraulic press comprises a plurality of single-rod return hydraulic cylinders symmetrically distributed at two sides of a main hydraulic cylinder of the hydraulic press, the plurality of single-rod return hydraulic cylinders are divided into several groups, each of the groups consisting of one balancing cylinder and one driving cylinder; a rod chamber of the balancing cylinder is communicated with an accumulator, the pressurized oil in the accumulator is filled into an oil chamber of the balancing cylinder, so that the balancing cylinder balances the weight of a walking beam and a working part of the walking beam; the driving cylinder is differentially connected; in the process of neutral-stroke-rapid-descending and ascending-returning of the walking beam and the working part of the walking beam.

A hydraulic drive including at least one hydraulic cylinder that includes a piston chamber, an annulus, and a piston that separates the piston chamber from the annulus. The hydraulic drive also includes a first hydraulic pump hydraulically connected with the piston chamber, a second hydraulic pump hydraulically connected with the annulus, a third hydraulic pump, and a directional control valve that has a first switching position and a second switching position. The third hydraulic pump in the first switching position of the directional control valve is hydraulically connected with the piston chamber, and the third hydraulic pump in the second switching position of the directional control valve is not hydraulically connected with the piston chamber.

An electro-hydrostatic drive for realizing a rapid movement during a rapid movement phase, a force-building movement during a force-building movement phase. The apparatus comprises a hydro-machine with variable volume and/or rotational speed, driven by an electric motor, for providing a volume-stream of a hydraulic fluid, a first cylinder with a piston chamber, an rod chamber, and a plunger rod, a reservoir, a pressure source, a relief valve, a check valve, a fluid connection between the piston chamber and the hydro-machine, a fluid connection between the rod chamber and the hydro-machine, a fluid connection between the piston chamber and the reservoir, a fluid connection between the rod-chamber-side port of the hydro-machine and the reservoir, a fluid connection, through the relief valve, between the reservoir and the pressure source. The relief valve is for pressure safety of the reservoir, and the check valve has a fluid connection from the pressure source to the rod-chamber-side port of the hydro-machine, during the rapid movement phase, a first part of the hydraulic fluid is piped through the fluid connection between the piston chamber and the hydro-machine and the fluid connection between the rod chamber and the hydro-machine, and a second part of the hydraulic fluid communicates through the fluid connection between the piston chamber and the reservoir, during the force-building movement phase, a first part of the hydraulic fluid is piped through the fluid connection between the piston chamber and the hydro-machine and the fluid connection between the rod chamber and the hydro-machine, and a second part of the hydraulic fluid is piped through the fluid connection between the rod-chamber-side port of the hydro-machine and the reservoir.

The invention relates to a hydraulic drive (1) comprising a working cylinder (2) and a travel cylinder (3) which is mechanically connected to the working cylinder (2). The working cylinder (2) and the travel cylinder (3) each comprise an upper and a lower cylinder chamber (21, 22, 31, 32), and all four cylinder chambers (21, 22, 31, 32) of the working and travel cylinder (2, 3) are connected to one another in a suitable manner in a closed pressure circuit (4) which is filled and prestressed with a hydraulic fluid (F). A rotational speed-variable hydraulic machine (5) with a first and second pressure connection (51, 52) is arranged in the pressure circuit (4) in order to conduct the hydraulic fluid (F) between the individual cylinder chambers (21, 22, 31, 32) of the working and travel cylinder (2, 3) during the operation (B) of the hydraulic drive (1). At least one first and second distributing valve (6, 7) are arranged in the pressure circuit (4) such that the respective valve switch positions (61, 62, 71, 72, 73) which are suitable for the different operating phases of the hydraulic drive (1) together with the suitably driven hydraulic machine (5) allow a common movement of the work and travel cylinder (2, 3) in one or the other piston movement direction (R1, R2). For this purpose, preferably only the first and the second distributing valve (6, 7) are arranged in the pressure circuit (4). The hydraulic drive (1) requires a minimum number of components, maintains a low installation complexity, improves the energy efficiency, can be constructed in a compact manner, and can be operated in a sufficiently variable manner.

A motor control device includes a pressure command unit calculating a pressure command for commanding pressure generated in a pressure control object, a pressure detection unit detecting the pressure generated in the pressure control object, a pressure control unit calculating a speed command for pressure control for the servo motor, based on the calculated pressure command and the detected pressure, and a servo control unit controlling speed of the servo motor, based on the calculated speed command. The pressure control unit performs an integral operation. When a direction of increasing pressure in the integral operation is defined as a positive direction in the integral operation, and a direction of decreasing the pressure is defined as a negative direction, a median between an upper limit in the positive direction and a lower limit in the negative direction in the integral operation is larger than zero.

A pressure measuring system, including a tube system having at least one first device for measuring pressure in a fluid. The at least one first device includes a coupling element, at least one pressure transducer and at least one measuring chamber, which can be filled with a fluid. Between the first device and the feed of the fluid, the tube system has a second device for regulating a fluid flow, the second device having a tube section through which fluid can flow and at least one tube clamp, which can be set in the regulation positions open, closed and perfused.