EP2846942B1 - Hydraulic extrusion press and method for operating a hydraulic extrusion press - Google Patents

Description

The invention relates to hydraulic extruders with a hydraulic main line driving at least one ram as the main consumer and with a hydraulic control pressure system. Likewise, the invention relates to a method for operating a hydraulic extruder with at least one ram in which at least the ram is driven by means of hydraulic oil from a main strand and used to control the extruder, a hydraulic control pressure.

Such extruders are known from the prior art, for example from EP 0 027 743 A1 Well known, the extrusion as such is a forming process in which preferably preheated heavy or light metal blocks, also called bolts, with the aid of a hydraulic press ram by a tool or by a die to strand-like semi-finished products, usually called profiles, are pressed ,

The common hydraulic actuators for the ram of these presses consist of a machine-dependent number of main pumps, which can be switched on demand by strand valves different consumer groups, such as several cylinders, in which piston for the hydraulic ram run.

From the consumer groups can be driven by respective pump circuit and consumer circuits each have an axis with individual axes of other consumer groups at the same time. In this case, it is generally possible to interconnect pumps to the various strands, the sequences and speeds of movement being defined and controlled via the pump allocation and the associated delivery flow regulation of the pumps. Extruders are built for different press forces, at present in a range between about 10 MN and about 150 MN. The tool or profile geometry and the pressing process result in different press forces and thus pressing pressures and different travel pressures for the main axes outside the pressing process for the respective machine size.

For this reason, hydraulic extrusion presses usually have a separate control pressure system to ensure that, for example, for a valve control or pump drives sufficiently reliable at any time a corresponding control pressure is available.

It is understood that during the retraction of the ram and during the loading of a new block or bolt or during other Rüsttätigkeiten non-productive times are inevitable in which a corresponding extruder is not productive. Accordingly, it is an object of the present invention to minimize the non-productive times.

As a solution, a generic hydraulic extruder and a generic method for operating a hydraulic extruder with the features of the independent claims are proposed.

In this case, for example by a hydraulic extruder with a at least one ram as the main consumer driving hydraulic main line and a hydraulic control pressure system, which is characterized in that the main line and the control pressure system are connected to each other on the pressure side, the non-productive times are reduced because oil from the control pressure system or Control oil is also available under given circumstances, especially if large oil flows are needed in the main line.

Accordingly, by a method for operating a hydraulic extruder with at least one ram in which at least the ram driven by hydraulic oil from a main strand and the control of the extruder, a hydraulic control pressure is used and which is characterized in that the control pressure also acts on the main strand will, the non-productive time will be reduced.

In this case, it is assumed in particular from the basic knowledge that it is also possible to reduce non-productive times by increasing the overall performance of an extrusion press, in that in particular larger and longer blocks or bolts can be pressed. This leads accordingly to a proportionate reduction of non-productive time, but here still nachwievor the control pressure pumps depending on the press cycles over long periods only serve to compensate for leakage losses and otherwise swing back to low flow, so that they are underutilized. The latter increases in the design of extruders to larger or longer blocks or bolts even further, which ultimately a correspondingly lower dimensions of the control pressure pumps for reasons of operational safety, since the necessary control pressures available for all operating times have to stand, is only very conditionally possible. In addition, any increase in power of such extruders is not possible for reasons of cost.

The use of control oil, for example, in return strokes, where usually large volumes must be moved at lower pressures, even with cautious estimation or as already shown in the first experiments, lead to side-time reductions between 0.5 and 0.8 seconds or more , It is assumed that further reductions in the non-productive times can be achieved in other sequences of motion, so that significant reductions in overall secondary times can be achieved in this respect, especially without having to significantly increase the overall design of the extruder, in particular with regard to its performance characteristics a suitably equipped extruder is relatively low, since ultimately only relatively inexpensive additional components, such as a supplementary connecting line and any valves or buffer for oil must be used.

In this respect, the non-productive times can be shortened in this way without increasing the drive power required or to be provided for the pressing process, which is correspondingly inexpensive.

Preferably, as already known from the state of the art, the main line is volume-controlled, so that the volume flows required precisely for the operation of the extrusion press in the shortest possible time can be reliably made available.

Cumulatively or alternatively, the control pressure system is preferably pressure-controlled or the control pressure is preferably maintained above a minimum pressure, so that the necessary control pressure is reliably available at all times. The minimum pressure is preferably a minimum of 80%, preferably a minimum of 90%, of the necessary control pressure to reliably enable control in this manner. It is understood that the pressures in the overall system are limited in a manner known per se to maximum pressures in order to be able to reliably avoid damage to the hydraulic system.

In this context, it should be mentioned that as the main consumer in the main line, for example, the master cylinder, as already mentioned, side cylinders, pick-up cylinders or a table displacement can be provided. Likewise, hydraulic motors, for example for spindle drives, or the like can accordingly be driven via the main line.

In this case, the various main consumers are preferably coupled to one another via consumer groups or consumer controllers, so that correspondingly a group-wise response is also possible. It is understood that the consumer groups or controls can be supplied individually or jointly from the respective main pumps with hydraulic oil, which can be readily implemented by appropriately switched strand valves in a conventional manner.

About the control pressure system can - as already known from the prior art per se - valve controls or hydraulic pumps but also auxiliary consumers who require relatively small volume flows, are operated without further notice. Corresponding auxiliary consumers can be, for example, block or bolt loaders or block or bolt loader tongs and the like. Likewise, release pressures or the like can be applied via the control pressure system or via the control pressure at appropriate locations.

The loading of the main line with the control pressure can be effected in particular via a proportional volume flow control. In this way, it can be ensured, in particular, that the control pressure does not abruptly drop when the main line is acted upon or the control pressure system remains manageable for every operating situation. For this purpose, means for proportional volume flow control in the direction of the main line, such as suitable throttles or pressure compensators, are preferably provided between the main line and the control pressure system.

Inadmissible feeding back of volume flow from the main line in the control pressure system is prevented by at least one check valve with a direction of the main strand opening direction.

Via the control pressure, hydraulic oil can be stored in one or more memories and the main branch can be acted upon from this memory, these memories or one of these memories. As a result, the oil volume, which can be provided via the control pressure can be increased considerably, especially with a suitable design of the overall hydraulic system, the memory can be emptied to below the control pressure in the main strand, so that this volume considerable oil volumes are made available to the main strand can be used advantageously for back-offs or similar movements, which take place under low pressure, advantageously for the reduction of time.

Preferably, hydraulic oil is stored only from a minimum control pressure of the control pressure in the memory, preferably in a separate memory, so that the maintenance of the required control pressure is primarily ensured.

In concrete implementation, it is accordingly advantageous if the control pressure system is connected to a memory. In this way, the memory can be filled with oil, in particular at the times when the control pressure pump or control pressure pumps merely serve to compensate for leakage oil losses or are under little load. Although this oil can also be used as a supply for the control pressure system. In particular, however, it is advantageous if at least parts of the oil stored in the memory of the control pressure system are also made available to the main branch under corresponding operating conditions.

To ensure the latter easily and with minimal losses, it is advantageous if at least one memory is arranged in a connecting line between the main line and the control pressure system.

In particular, the memory between a pressure-adjusting valve in the direction of the control pressure system in the connecting line on the one hand and means for proportional flow control and / or a check valve in the direction of the main strand on the other hand can be arranged. By the pressure switching valve can be ensured that such a memory is filled only from certain pressures with oil from the control pressure system, while on the means for proportional flow control, the oil from the memory then, as already described above, the main strand can be provided If necessary, both the accumulator and the control pressure system can be secured against volume flow from the main branch via the non-return valve.

It is understood that the features of the solutions described above or in the claims can optionally also be combined in order to implement the advantages in a cumulative manner.

Figur 1

eine perspektivische Ansicht einer hydraulischen Strangpresse;

Figur 2

eine schematische Darstellung von zur Erläuterung der Erfindung wesentlichen Ausschnitten eines ersten hydraulischen Systems für eine Strangpresse;

Figur 3

eine schematische Darstellung von zur Erläuterung der Erfindung wesentlichen Ausschnitten eines zweiten hydraulischen Systems für eine Strangpresse;

Figur 4

eine schematische Darstellung von zur Erläuterung der Erfindung wesentlichen Ausschnitten eines dritten hydraulischen Systems für eine Strangpresse;

Figur 5

eine schematische Darstellung von zur Erläuterung der Erfindung wesentlichen Ausschnitten eines vierten hydraulischen Systems für eine Strangpresse; und

Figur 6

eine schematische Darstellung von zur Erläuterung der Erfindung wesentlichen Ausschnitten eines fünften hydraulischen Systems für eine Strangpresse.

Further advantages, objects and features of the present invention will be explained with reference to the following description of exemplary embodiments, which are shown in particular in the appended drawing. In the drawing show:

FIG. 1

a perspective view of a hydraulic extruder;

FIG. 2

a schematic representation of essential to explain the invention cutouts of a first hydraulic system for an extruder;

FIG. 3

a schematic representation of illustrating the invention essential sections of a second hydraulic system for an extruder;

FIG. 4

a schematic representation of illustrating the invention essential sections of a third hydraulic system for an extruder;

FIG. 5

a schematic representation of illustrating the invention essential sections of a fourth hydraulic system for an extruder; and

FIG. 6

a schematic representation of the explanation of the invention essential cutouts of a fifth hydraulic system for an extruder.

In the FIG. 1 illustrated hydraulic extruder 100 comprises a pressing member 110 and a pump table 120 with five main pumps 2. The pressing member 110 includes a master cylinder 1.1 and a plurality of slave cylinder 1.1, with which a not shown but known compression ram can be moved. For pressing a block or bolt 140 is loaded by means of a block loader, not shown, but also known per se in a hydraulically operated block receiver 150 before the ram presses the block or bolt through a die and the workpiece, the hydraulic extruder 100 by a Opening 160 leaves.

As can be seen immediately, the hydraulic extruder 100 is a relatively large plant operated by a hydraulic controller 130.

The hydraulic control 130 can be realized in different ways, wherein FIGS. 2 to 6 corresponding embodiments, but exemplified for only two main pumps 2, are shown. The latter drive main consumers 1, which in these embodiments, the cylinders 1.1 and 1.2 for the ram, a hydraulic motor 1.3 for a spindle drive and a cylinder 1.4 for a pickup, but may include a table shift or other aggregates in other embodiments, via main pumps 2 on , where in the FIGS. 2 to 6 in each case a first main pump 2.1 and a second main pump 2.2 are shown, which are via strand valves 3, namely a first strand valve 3.1 and a second strand valve 3.2 respectively hydraulically the main consumers 1, which can be operated by consumer controls 4.

Here, these embodiments have a first consumer control 4.1, in which the two cylinders are summarized 1.1 and 1.2 for the ram, and a second load control 4.2, in which the hydraulic motor 1.3 and the transducer cylinder 1.4 are summarized.

By grouping into consumer controls 4, the grouped main consumers can accordingly be supplied synchronously with hydraulic oil without further ado. It is understood that the respective main consumers 1 can be combined in any manner to form further consumer controllers 4.

As can be seen immediately, both main pumps 2 can be switched on via the string valves 3, in each case two consumer controllers 4, respectively.

In concrete implementation, the two main pumps 2 are identical pumps, which are each driven by a corresponding 200 kW motor and have a flow rate control Q (Quantity) to flow. As a rule, a number of identical pumps are connected in parallel, depending on the required overall power, whereby the number of main pumps 2 does not necessarily have to correspond to the number of consumer controls 4. In other embodiments, the pumps and corresponding motors may have different dimensions, for example, up to 1,000 kW pumps or motors, or even larger, with an optimum usually being found depending on the required power and the associated costs. It is understood that the number of main pumps 2, the strand valves 3 and the consumer controls 4 can be adapted to the respective specific requirements.

To the consumer controls 4 lead hydraulic main strands 5, it being understood that here, if necessary, more or more main strands 5 can be provided.

The consumer controls 4 empty in a conventional manner in a container, from which in turn the main pumps 2 are fed in a conventional manner, in which case may be provided filtering operations or the like.

From a corresponding container, preferably from the same container, a control pressure system via the control pressure pump 11 is fed, which control pressure on control oil for valve control or, for example, for detachment processes, in particular by high start-up or tear-open, and for secondary consumers, such as block loaders or block loader, which have a small volume consumption, available provides. In this embodiment, a 90 to 100 kW pump or a pump with a 90 to 100 kW motor is used in this embodiment, whose control oil control p (pressure) is carried out under pressure. In this way it can be ensured that at any time sufficient control pressure for safe operation of the valves is available. It is understood that - depending on the concrete implementation - other services for the control pressure pump 11 or other control pressure pumps can be provided.

At the in FIG. 2 illustrated embodiment, the control pressure system is connected via a not numbered connecting line to the hydraulic main line 5.2, wherein means are provided for proportional flow control in this connection line, which a throttle 13, in this embodiment concretely a manual or proportional throttle and a 2-way pressure compensator, 14th include. In addition, a check valve is provided in the connecting line, which prevents a backlash in the direction of the control pressure system. In order to use the power of the control pressure pump 11 as completely as possible, a hydraulic accumulator 12 is also provided, in which hydraulic oil of the control pressure system can be cached and retrieved as needed.

As can be seen immediately, it is possible in this way, the control pressure pump 11 to promote even during times of low flow rate in the hydraulic accumulator 12 in order to provide the corresponding volume to the main consumers 1 available. With the given power specifications, five 200 kW motors for the main pumps 2 and a 100 kW motor for the control pressure pump, this can be provided by about one tenth more power to have more volume of hydraulic oil available, which in particular can be provided for volume-intensive movements.

While at the in FIG. 2 illustrated embodiment, the throttle 13 is designed as a manual or proportional throttle, has in FIG. 3 illustrated embodiment as a throttle 13, an electric proportional directional control valve, so that both the first main branch 5.1 and the second main branch 5.2 can be acted upon accordingly with control pressure or hydraulic oil from the control pressure system. For this purpose, each of the corresponding connecting lines is connected to a check valve and a shuttle valve 15 is provided between the two connecting lines to the two main strands 5, which accordingly acts on the 2-way pressure compensator 14.

It is understood that with several main strands 5, a corresponding number of shuttle valves 15 may be provided to tap the relevant load pressure for the 2-way pressure compensator 14.

Likewise, depending on the specific requirements of several throttles 13, pressure compensators, in particular 2-way print carriage 14, and connecting lines and check valves may be provided.

In this context, it is understood that as a proportional volume flow control means, if necessary, other devices, for example two arrangements, which the throttle 13 and the 2-way pressure compensator 14 after FIG. 2 can be provided.

The arrangement after FIG. 4 corresponds to the arrangement according to their ability to control pressure to the main strands 5 available FIG. 2 , so that here too the control pressure can only be made available to the second main branch 5.2, but in both embodiments via the second strand valve 3.2 hydraulic oil from the second main pump 2.2 and the first main strand 5.1 can be provided so that accordingly both main pumps 2 for the first consumer control 4.1 can be used while the control pressure or the hydraulic oil originating from the control pressure system is simultaneously available to the second consumer control 4.2.

In deviation from the embodiment according to FIG. 2 two control pressure pumps 11 and 21 are provided, wherein the control pressure pump 11 is controlled at a high pressure (HD) and the control pressure pump 21 to a low pressure (ND). In this case, the control pressure system with high pressure, for example, the locking of valves and any start-up or breakaway pressures are used, while above the low control pressure driving pressures of ancillaries or valves can be provided with large adjustment paths.

Both control pressure strands each have hydraulic accumulators 12, 22 and are in each case via a proportional volume flow control, in this embodiment each consisting of a throttle 13, 23, in particular a manual or proportional throttle, and in each case a 2-way pressure compensator 14, 24 and one each Check valve connected to the second main branch 5.2, it being understood that, if necessary, a connection to the first main branch 5.1 or a connection to both main strands 5, for example via the arrangement according to FIG. 3 , can be provided. Through the use of both high and low control pressure, if necessary, both high start-up or Losreißdrücke and lower required driving pressures can be realized. This results in lower throttle losses, in particular with regard to the low-pressure region, with the height of the required pressures in the design and assignment of a corresponding hydraulic extrusion press 100 in each case generally being taken into account in all embodiments. In particular, it must also be examined in which specific phases of the process an additional movement or speed increase leads to a reduction of the non-productive time, and how the circuit is to be interpreted most energetically most effectively. From this, the storage volume can then also be determined and, if necessary, the power of the selected control pumps adapted.

At the in FIG. 4 The arrangement shown, the low pressure range of the control pressure system is passively switched on so that at high start-up or Losreißlasten initially only the high-pressure region is effective in the further course of motion, however, no switching operations are required.

It is understood that the additional, provided by the control pressure pump 11 and by the control pressure flow can also be switched directly to a main consumer 1, as this example in the in FIG. 5 illustrated embodiment for the transducer cylinder 1.4 is done. As a result, the pick-up cylinder 1.4 can also be moved independently of the corresponding main branch 5.2 or of the corresponding second consumer control 4.2. Thus, two main consumers 1.3 and 1.4 of a main line 5 can be moved simultaneously without further notice. Thus, for example, in a known extruder, the pre-acceleration of the spar during return stroke, before a pickup for the ride in the "total differential" touches to take the strut for the rest of stroke, done accordingly. The touchdown must then no longer be done with speed approaching "zero", but can happen on the fly, so at higher speed. Since this minimizes braking and acceleration, the estimated time savings can be between 0.5 and 0.8 seconds, depending on the machine type.

As with reference to the embodiment according to FIG. 6 shown as an example, may be provided in the connecting line between the control pressure pump 11 and main strands 5 of the control pressure pump 11 initially a pressure switch valve 31 and then a supplementary memory 32 before then the proportional volume flow control, which in turn in this embodiment of a throttle 13 and a 2-way -Druckwaage 14 is, follows. In this way, the reservoir 32 is supplied with hydraulic oil from the control pressure pump 11 only when a minimum control pressure of the control pressure is reached and maintained. In this respect, the control pressure over a secondary acceleration has priority, so the control is not affected by this. In particular, by this embodiment, the useful volume of the memory 32 relative to the useful volume of the memory 12 can be increased by extending the usable pressure range down, since the memory 32 can be emptied to pressures which are below the control pressure. This reduces the number or size of memory used.

It is understood that the various embodiments which in the FIGS. 2 to 6 can be combined, as immediately apparent. This applies in particular, for example, to the in FIG. 4 illustrated embodiment, which according to the in Figures 3 and / or 6 embodiments shown in high and / or low pressure area added or alternatively can be configured. Preferably, the supply of the additional volume flow to the main strands 5, even if this is possibly done directly to a main consumer 1, as in FIG. 5 exemplified via pressure-independent flow control valves as a proportional volume flow control means. These generally have a throttle 13, for example, implemented by a proportional valve, a proportional throttle or an electric proportional directional valve, and a 2-way pressure compensator 14. If the system design is correct, neither the control pressure actually present in the system nor the required and possibly variable driving pressure or consumption pressure of the main consumer 1 should have an influence on the flow rate of the flow control valves or the proportional volume flow control means. This in turn makes it possible for the processes and speed to be preselectable and to remain reproducible.

In particular, parallel circuits and a variety of combination options in the FIGS. 2 to 6 explained detailed solutions are used for a concrete system design. LIST OF REFERENCE NUMBERS 1 main consumers 12 hydraulic storage 1.1 Master cylinder for press punches 13 throttle 1.2 Slave cylinder for press punches 14 2-way pressure compensator 1.3 Hydraulic motor for spindle drive 15 shuttle valve 1.4 Cylinder for transducers 21 Pilot pump 2 main pumps 22 hydraulic storage 2.1 first main pump 23 throttle 2.2 second main pump 24 2-way pressure compensator 2.3 third main pump 2.4 fourth main pump 31 Pressure sequence 2.5 fifth main pump 32 supplementary storage 3 balancing valves 100 hydraulic extruder 3.1 first strand valve 110 pressed part 3.2 second strand valve 120 pumps table 130 hydraulic control (numbered as an example) 4 consumer management 4.1 first consumer control 140 Block or bolt 4.2 second consumer control 150 Billet 160 opening 5 hydraulic main strands 5.1 first main strand p Control oil control on pressure 5.2 second main strand Q Flow rate control to flow rate 11 Pilot pump

Claims (12)

1. A hydraulic extrusion press (100) having a main hydraulic line (5) that drives at least one ram as the main consumer (1), and having a hydraulic control pressure system, characterized in that the main line (5) and the pressure control system are connected with one another on the pressure side.
2. The extrusion press according to claim 1, characterized in that the main line (5) is volume-regulated and/or the control pressure system is pressure-regulated.
3. The extrusion press according to claim 1 or 2, characterized in that a back pressure valve against back pressure in the direction of the control pressure system and/or means for proportional volume stream control in the direction of the main line (5) are provided between the main line (5) and the control pressure system.
4. The extrusion press according to any one of claims 1 to 3, characterized in that the control pressure system is connected with a storage device (12, 22, 32).
5. The extrusion press according to claim 4, wherein the storage device (32) is disposed in a connection line between the main line and the control pressure system.
6. The extrusion press according to claims 3 and 4 or according to claims 3 and 4 and 5, characterized in that the back pressure valve or the means for proportional volume stream control are disposed in the connection line between the storage device and the main line, and that a pressure sequencing valve (31) is disposed between the control pressure system and the storage device (32).
7. A method for operating a hydraulic extrusion press (100) having at least one ram, in which at least the ram is driven by means of hydraulic oil from a main line (5), and a hydraulic control pressure is used to control the extrusion press (100), characterized in that the control pressure is also applied to the main line (5).
8. The method according to claim 7, characterized in that application of the control pressure to the main line (5) takes place by way of proportional volume stream control.
9. The method according to claim 7 or 8, characterized in that the main line (5) is volume-regulated and/or the control pressure is kept above a minimum pressure.
10. The method according to any one of claims 7 to 9, characterized in that by way of the control pressure, hydraulic oil is stored in a storage device (12, 22, 32) and applied therefrom to the main line.
11. The method according to claim 10, characterized in that the storage device (32) is emptied into the main line to below the control pressure.
12. The method according to claim 10 or 11, characterized in that the hydraulic oil is stored in the storage device (32), which is preferably provided additionally, only starting from a minimum storage pressure.

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