WO2015177285A1

WO2015177285A1 - Bar press with hydraulic drive

Info

Publication number: WO2015177285A1
Application number: PCT/EP2015/061270
Authority: WO
Inventors: Andreas WERSHOFEN-CROMBACH; Ewald Hagen; Stephan Frehe
Original assignee: Sms Meer Gmbh
Priority date: 2014-05-21
Filing date: 2015-05-21
Publication date: 2015-11-26
Also published as: CN106457328A; DE102014209685B3; TW201600192A; EP3145650A1; JP2017518189A; US20170113256A1

Abstract

The invention relates to a bar and tube press for shaping metal ingots into profiles, tubes, bars or the like, comprising a male die and a female die, through which a metal ingot can be pressed by means of the male die, comprising a container, and comprising a driving device, in which the driving device comprises at least one main cylinder for applying the main pressing force of the male die to the metal ingots, characterized in that on the one hand the driving device comprises at least one speed-controlled internal gear pump for providing the hydraulic oil to the at least one main cylinder, by means of which the at least one main cylinder can be driven, and in that on the other hand the driving device additionally comprises at least one hydraulic advance and/or return cylinder for moving the male die in relation to the female die or at least one electrical drive for moving the male die in relation to the female die, by means of which the male die can be moved into a position in which the speed-controlled internal gear pump only then interacts with the at least one main cylinder in such a way that the main pressing force is applied to the male die by means of the at least one main cylinder.

Description

Extruder with hydraulic drive

1. Field of the invention

The invention relates to a strand and tube press for forming metallic blocks in profiles, tubes, strands or the like, with a punch and a die, through which a metallic block can be pressed by means of the punch, with a billet receiver, and with a drive device at which the drive means comprises at least one master cylinder for applying the main pressing force of the punch to the metallic block.

2. State of the art

Such extrusion and tube presses are known for decades from the prior art and are used to produce a variety of components made of usually metallic materials, which pressed by a die undergo a transformation with high degree of deformation.

Main features of conventional extrusion presses are a blocker between the punch and the billet and a pressing force generation by means of a master cylinder and a feed / retract cylinder, whereby all auxiliary movements, including the employment of the extruder to different block formats and the supply of the metallic block to the die, performed by hydraulic cylinders become. The size of the hydraulic drive is determined by that of the Extrusion and applied pressing force and optionally determines the required for the desired forming press speed.

In recent decades, the further development of the known extrusion and tube presses to so-called short-stroke extruders, in whose case the increase in the block length of the master cylinder stroke was designed for a particular block length, in particular to provide a compact press frame. In this case, in a so-called front loader construction, the block loader was arranged between the die block and the punch and a symmetrical block dousing was carried out. The hydraulic drives and hydraulic tanks required for the movement of the individual components of the extrusion and tube press as well as the press force application were arranged in the periphery of the movable components.

Such extruders usually bring about pressing forces of about 10 to more than 160 MN. Large extruders with 100 MN press forces are able to reshape block lengths of more than 2,000 mm with a block diameter of more than 1,000 mm. Such extruders are known for example from DE 10 227 488 B3 or EP 1 526 930 B1.

The hydraulic oil is conveyed in the prior art using axial piston pumps to the hydraulic drive means and / or the means for applying the pressing force between the die and punch. However, such axial piston pumps are relatively expensive. In addition, they have the disadvantage that they have a high pulsation, especially at low speeds, which ultimately leads not only to unwanted vibrations, but also to a relatively high noise level. For health and safety requirements, such extrusion and tube presses therefore usually have a not inconvenient soundproofing. In addition, the known extrusion and tube presses have a relatively high energy consumption. 3. Object of the invention

It was therefore an object of the invention to provide a strand and tube press for forming metallic blocks, which is able to overcome the disadvantages known from the prior art to overcome.

This object is achieved in the sense of the invention with a strand and tube press, comprising the features of claim 1. Advantageous embodiments of the invention are set forth in the dependent claims.

4. Summary of the invention

According to the invention, the drive device on the one hand at least one speed-controlled internal gear pump for providing the hydraulic oil to the at least one master cylinder, by means of which the at least one master cylinder is driven, and that the drive means on the other hand additionally at least one hydraulic feed and / or retraction cylinder for moving the punch relative to Stem or at least one electric drive for moving the punch relative to the die comprises, by means of which the punch is movable to a position in which the speed-controlled internal gear pump only then interacts with the at least one master cylinder such that the main pressing force by means of at least one master cylinder on the Stamp is applied.

The thus configured drive device of the extrusion and tube press, it is possible to operate the speed-controlled internal gear pump or Snnenzahnradpumpen standard electric motors with larger mass carrier in combination with smaller-sized frequency inverters.

This has the advantage that the drive device can be provided even more cost-effective on the extrusion and tube press.

For the purposes of the invention, the term "small-sized frequency converter" means frequency converters which are normally not dimensioned sufficiently large for the selected size of standard electric motors.

This special interaction between an over-dimensioned standard electric motor with respect to a frequency converter and just such a frequency converter, or vice versa, is essentially only possible in that the speed-controlled internal gear pump is used substantially exclusively for applying the main pressing force, the main press force transmission to the stamp means the at least one master cylinder takes place only when the punch has been moved to a certain position. And this movement of the punch in this particular position is accomplished by means of the at least one hydraulic feed and / or return cylinder or the at least one electric drive.

By means of the at least one hydraulic feed and / or return cylinder or the at least one electric drive, it is possible to realize very rapid movements of the punch in the auxiliary time with respect to the main press transfer in a structurally simple manner.

This design is in contrast to conventional approaches, in which special servo drives are used with low inertia. In the present case, with simple and widely available devices on the market, it is generally achieved that by switching off the pumps, lower losses occur than was possible with non-variable-speed drive and with the use of axial piston pumps. Thus, a highly energy-efficient operation of the extrusion and tube press is possible.

In addition, a frequent on-off operation is easily possible and a simple flow adjustment by speed change can be achieved.

Finally, such internal gear pumps are much quieter than axial piston pumps, which optionally eliminates the sound insulation commonly used in extrusion and tube presses entirely eliminated, but at least can be realized significantly simpler and space-saving.

The use of variable-speed internal gear pumps also allows a simple and robust construction of all components and provides a maintenance-friendly and easy-to-understand drive system.

Such internal gear pumps, which are already known from the prior art in a variety of embodiments, are particularly suitable for use with variable-speed drive and have already proved their special suitability for load changes and in terms of energy consumption in internal tests.

Furthermore, it is very advantageous that in the present extrusion and tube press also can be dispensed with additional hydraulic control blocks or the like, which otherwise for switching the at least one internal gear between the at least one master cylinder and at least one side cylinder or pick-up shift cylinder or the like is mandatory. In this respect, in particular a better hydraulic efficiency can be achieved thereby.

It is thus possible in the context of the invention to achieve a significant minimization of the initial costs, a low noise emission during operation of the systems, a good efficiency with energy-efficient drive and a minimization of the pulsation at low speeds.

In particular, the device according to the invention also allows a complete standstill of the pump drives when no hydraulic oil has to be made available under pressure.

This leads to an energy saving potential compared to conventional extruders of about 33% to 55%.

At this point, it should again be noted that the at least one speed-controlled internal gear pump is preferably used only for the actual reforming process and possibly also for a press residual scissor process.

Preferably, the at least one frequency-controlled internal gear pump is controllable by means of a suitably designed control of the extrusion and tube press such that the combination of the number of internal gear pump used n and selected frequency gives the best possible efficiency.

For this purpose, the associated characteristic curves of the intended Innenzahnradpum- pen, such as with a suitable test rig device or the like, depending on pressure and speed have previously been measured. The resulting set of curves on curves is deposited in the control of the extrusion and tube press in a suitable manner.

In the present case, it is particularly advantageous that the flow rate and the number of internal gear pumps are calculated by a linear interpolation in a two-dimensional field, in real time first with a theoretical value. Subsequently, it can be adjusted even finer by means of a control device designed for this purpose.

By this precontrol a very accurate and fast speed control is achieved in the actual pressing process.

It should be mentioned again that it is particularly advantageous that at least one hydraulic feed and / or retraction cylinder is provided for moving the stamp relative to the die.

In particular, this ensures that the main force transmission is effected by means of one or more master cylinder, the feed and the withdrawal of the punch relative to the die in a position in which the press force transfer is to use, and out of this, but by means of preferably smaller feed and / or retreat cylinder.

In other words, this means that the drive device comprises at least one speed-controlled internal gear pump for supplying the hydraulic oil to the at least one HauptzySinder, by means of which the main press transfer occurs, and at least one hydraulic feed and / or retraction cylinder for moving the punch relative to the die or at least one electric drive for moving the punch relative to the die, to move the punch to a position in which the main press force transmission begins. As a result, the amount of hydraulic oil to be delivered over the entire operation of the extrusion and tube press is limited to the minimum necessary for such drive concepts.

Furthermore, the Snnenzahnradpumpe must only be driven with an increased drive power when main press forces on the extrusion and tube press must be actually applied, that is, if by means of at least one master cylinder, a main press force transfer must be made on the stamp. Otherwise, the internal gear pump can be driven at a significantly reduced power. Or the internal gear pump is completely out of operation. As a result, the drive device or the entire extrusion and tube press works energetically much more effective.

In a preferred embodiment of the invention, the drive means comprises means for moving the punch and / or the billet and / or the die and means for applying a pressing force between the die and punch.

More specifically, the drive means comprises means for moving the punch and / or the block picker and / or a tool slide comprising the die and means for applying a pressing force between the tool slide and the punch.

As a rule, the die is part of the tool slide and the die is moved together with this tool slide. This is generally true in the present invention.

In addition, the drive device preferably also comprises means for moving a press rest scissors. It is understood that the at least one hydraulic feed and / or retraction cylinder for moving the punch relative to the die, but also in particular the at least one electric drive for moving the punch relative to the die can be formed very different.

In particular, with regard to the electric drive, it is advantageous if this comprises a standard asynchronous machine, since the electric drive can be structurally particularly simple realized.

In an alternative and also particularly preferred embodiment of the invention, however, at least the at least one electric drive is an electric servo drive for moving the punch relative to the die.

As a result, a system concept is realized, which causes the use of pressure force substantially hydraulically using modern hybrid technology, but all other movements of the components of the extrusion and tube press electrically effects, such as hiring the press ram in a force introduction position, the movement of the block loader, if necessary, the movement of the press shear and the like.

Finally, over the conventional hydraulic drive, high energy efficiency can be achieved thanks to the hybrid electrohydraulic drive concept, where hydraulic savings are preferably achieved through reduced pump capacity, smaller reservoir volume for the hydraulic fluid, preferably shorter tubing, and smaller valve sizes. Energy savings Saving in the electric servo drives preferably by suitable means for energy recovery. Such a hybrid technology in extrusion and tube presses is disclosed, for example, in International Patent Application Publication No. WO 2013/064250 A1.

It is also preferred in this context if the Snnenzahnradpumpe is operable in the range of startup to provide the desired system pressure under mixed friction. This significantly reduces the pulsations generated by the pump, especially at low speed ranges, compared to conventional axial piston pumps and to the unavoidable minimum.

In addition to the mixed friction, the at least one Snnenzahnradpumpe is cumulatively or alternatively even under an external hydrostatic lubrication operable.

In order to start the at least one internal gear pump at the present extrusion and tube press more often from a zero-speed operation without prejudice and operated in particular in a mixed operation, it is advantageous without the other features of the invention, if preferred as a hydraulic oil Mineral oil is used, which is characterized by a high shear strength.

Moreover, it is preferred if the drive device is connected to a control unit in which a characteristic curve or a plurality of characteristic curves for the internal gear pump and / or its drive motor or motors are stored. As a result, it is achieved by simple means that the motors and pumps used can be operated under energetic aspects at the optimum operating point. The software-based storage of the characteristics in the control unit allows in this regard the direct control of the pumps and / or drive motors pressure-dependent, so as to obtain the desired hydraulic oil flow rate. Particularly preferred is when the pulsation of the internal gear pump, in particular the preferred internal gear pump, especially at low speeds is lower than in axial piston pumps, preferably by a measure of at least 20%, more preferably at least 30% compared to the pulsation of conventional axial piston pumps.

In addition, it should be mentioned again here that the drive concept can be implemented significantly more quietly at the present extrusion and tube press by the internal gear pump compared to an external gear pump.

With regard to the present drive device, it is particularly advantageous for the internal gear pump to have only three movable essential components.

Claims

claims

Extrusion and tube press for forming metallic blocks into profiles, tubes, strands or the like, with a punch and a die, through which a metallic block can be pressed by the punch, with a billet receiver, and with a drive device, wherein the drive means at least a master cylinder for applying the main pressing force of the punch to the metallic block, characterized in that the drive means comprises at least one speed-controlled internal gear pump for supplying the hydraulic oil to the at least one master cylinder by means of which the at least one master cylinder is drivable,

and in that the drive means, on the other hand, additionally comprises at least one hydraulic feed and / or return cylinder for moving the punch relative to the die or at least one electric drive for moving the punch relative to the die, by means of which the punch is movable to a position in which the speed controlled one Innenenzahnradpumpe only then interacts with the at least one master cylinder such that the main pressing force is applied by means of at least one master cylinder on the stamp.

Extrusion and tube press according to claim 1, characterized in that the drive means comprises means for moving the punch and / or the block receiver and / or the die and means for applying a pressing force between the die and punch. Extrusion and tube press according to one of claims 1 or 2, characterized in that the at least one electric drive, preferably an electric servo drive for moving the punch relative to the die.

Extrusion and tube press according to one of the preceding claims, characterized in that the internal gear pump is operable in the range of starting up to the provision of the desired system pressure under mixed friction.

Extrusion and tube press according to one of the preceding claims, characterized in that the drive device is connected to a control unit in which a characteristic curve for the internal gear pump and / or its drive motor or motors, preferably a plurality of characteristics, is deposited / are.

Extrusion and tube press according to one of the preceding claims, characterized in that the pulsation of the internal gear pump is lower, in particular at low speeds, than in axial piston pumps, preferably by at least 20%, preferably by at least 30%.