AT524160B1 - Hydraulic drive device for a shaping machine - Google Patents

Abstract

Hydraulic drive device (1) for an injection molding machine with a hydraulic drive unit (2), a piston-cylinder unit (3), a hydraulic line system (4) and a control or regulating unit (5), the hydraulic drive unit (2) being Control or regulating unit (5) can be controlled to generate a certain hydraulic power, wherein in a first operating mode (B1) - in which the differential operation is active - the piston-cylinder unit (3) with low force (F) and with high Speed (V) can be controlled and in a second operating mode (B2) - in which the differential mode is inactive - the piston-cylinder unit (3) can be controlled with high force (F) and at low speed (V). To switch from the first operating mode (B1) to the second operating mode (B2), the hydraulic drive unit (2) is used to output a changed hydraulic power controllable.

Description

description

The present invention relates to a hydraulic drive device for a molding machine, in particular an injection molding machine or transfer press, having a hydraulic drive unit for generating hydraulic power, a piston-cylinder unit, a hydraulic line system connecting the hydraulic drive unit to the piston-cylinder unit, in which a hydraulic power can be adjusted via the hydraulic drive unit. The hydraulic line system has a first connection point for connection to the hydraulic drive unit, a second connection point for connection to a rod-side chamber of the piston-cylinder unit, a third connection point for connection to a piston-side chamber of the piston-cylinder unit, a second connection point the circulating line connecting the third connection point and at least one switching element for setting a differential operation, wherein in a differential position of the switching element the differential operation can be built up via the circulating line. In addition, a control or regulating unit is provided for controlling or regulating the hydraulic drive device, the hydraulic drive unit being controllable via the control or regulating unit to generate a specific hydraulic power and the switching element being controllable via the control or regulating unit, wherein in a first operating mode - in which the differential mode is active - the piston-cylinder unit can be controlled with low force and at high speed and in a second operating mode - in which the differential mode is inactive - the piston-cylinder unit can be controlled with high force and at low speed is. Furthermore, the invention relates to a shaping machine with such a hydraulic drive device, a method for operating such a hydraulic drive device and a computer program product for carrying out a method.

[0002] Differential circuits of piston-cylinder units have been state of the art for years and are used in various applications with different transmission ratios. An increased pressure or an increased force is built up by increasing the effective diameter (or the effective piston area). In this way, it is possible to easily implement two different operating states (first operating mode and second operating mode) with a differential piston-cylinder unit with the same hydraulic power (i.e. with the same pressure and the same pump delivery rate):

- High speed and therefore low effective force (differential operation).

- High power and low speed.

In most cases, it is selected before a movement, which operating state is selected. An example in the applicant's molding machines is the use in injection, with either “increased injection pressure” or “differential injection” being possible during the injection process. A typical cylinder ratio is 1:5. A further example of the applicant's shaping machines is the use when opening by means of an express lifting device. The opening usually takes place by means of the express lifting device at high speed in differential operation, while the differential circuit can be deactivated for an increased opening force. A typical cylinder ratio here is 1:2.

[0004] However, applications in which switching occurs during the movement of the piston-cylinder unit are also known. For example, in the case of a hydraulic toggle lever mechanism, in which the actual closing process is carried out at high speed and with low power requirement in differential operation, the differential switching can be canceled when the toggle lever is pushed through, whereby the maximum force (for the build-up of closing force) is available.

Examples of differential circuits are given below.

DE 37 35 123 A1 describes a hydraulic drive device for a punching or embossing tool. At the outset, the problem of switching over the differential hydraulic cylinder provided as the drive element in accordance with the load is discussed. For this purpose, the area changeover valve is designed as an exclusively pressure-dependent controlled valve in which

the adjustable closing force of a check valve the response pressure is adjustable. Nevertheless, with such a configuration, abrupt changes in force or speed can occur, which lead to increased wear or to an unfavorable behavior of the movement of the piston-cylinder unit.

[0007] EP 0 464 481 B1 describes a device for controlling a hydraulic motor. Specifically, this document shows a differential cylinder, such as is used for example as a locking cylinder in a plastic injection molding machine to actuate a mold. The differential cylinder has a cylinder chamber associated with its large effective area and an annular chamber associated with the smaller effective area, with their area ratio being 2:1. The device essentially has, as components, a proportional valve designed as an electrohydraulic control valve, a changeover valve controlled as a function of differential pressure, a pilot-controlled check valve and two check valves. With regard to the mode of operation, it is described, among other things, that the pressure valve is designed as a proportional valve, so that different pressures can be programmed with it. In particular, the mold closing safety pressure and the closing pressure in the differential cylinder and, if necessary, other pressure functions, such as in a pressure pad, can be regulated in this way. An additional throttle is provided in the control line for these pressure functions. According to this document, the changeover valve only has the function that when retracting there is an additional opening in order to be able to push out a large volume.

WO 2006/042500 A2 describes and shows a hydraulically actuated casting unit, the hydraulic circuit diagram of a casting unit of a die-casting machine being shown. The casting unit has a casting cylinder, the piston of which actuates a casting piston guided in a casting sleeve, not shown. The molten mold material is introduced into this casting sleeve or filling chamber and then moved in the direction of a mold by the axial feed of the casting plunger, so that it is filled with melt during the mold filling phase and the melt contained in the mold is compressed during the holding pressure phase and any shrinkage is compensated for. The casting cylinder is actuated via the control arrangement, which essentially consists of a continuously adjustable directional valve, a counter-pressure valve, a counter-pressure control valve, two lockable check valves, an LP check valve, an HP control valve and a directional seat switching valve. It is also stated that switching to the mold filling phase also takes place without pressure. The continuously adjustable directional valve is designed in such a way that during the pre-filling phase, it directs the pressure medium volume flow flowing out of an annular space of the casting cylinder to the cylinder chamber that is effective in the extension direction, so that the pump has to deliver correspondingly less pressure medium and there is less pressure drop at the regulating control edge of the directional valve. The differential circuit further improves the resolution and thus the control quality. However, the differential circuit cannot be activated in a controlled manner; only other control options are described.

Finally, reference can also be made to DE 10 2017 206 581 A1, which shows a valve arrangement for arm cylinders with two operating states. Specifically, this is about a valve arrangement for a non-generic excavator. An advantage of the invention is that a particularly smooth transition is made possible when the direction of movement of the differential cylinder or the actuator is reversed. In the third position, the actuator would be braked abruptly because of its inertia, preventing a smooth movement. This is prevented by the second position of the second valve. In this, a fluid flow path is opened starting from the first working connection via the second valve via a return connection to the tank. This fluid flow path bypasses the first check valve to allow fluid flow from the first workport to the tank. The second working port is connected to the tank via an optional second check valve. This only allows fluid flow from the tank to the rod side of the differential cylinder. This prevents cavitation from occurring on the rod side when the differential cylinder moves in the second mode. In doing so, pressurized fluid is sucked from the tank to the rod side. It is thus described that the differential

The shifting effect exhibits a smooth transition, but abrupt changes in force or speed can still occur, especially if the hydraulic power supplied to the differential shifting is very high.

[0010] Other design variants known from the prior art can be found in JP S59121203 A, EP 4 85843 A1 or EP 0656481 A1.

In the prior art, it is generally disadvantageous that an abrupt change in speed or force occurs according to the cylinder area ratios when the differential circuit is activated or deactivated during the movement of the piston-cylinder unit.

The object of the present invention is therefore to create a hydraulic drive device that is improved over the prior art.

In particular, abrupt changes in movement of the piston-cylinder unit should be avoided as far as possible.

This is solved by a hydraulic drive device having the features of claim 1. Accordingly, the invention provides that, on the one hand, for switching from the first operating mode to the second operating mode to at least partially compensate for an increase in force and/or a drop in speed of the piston-cylinder unit that occurs during switching, the hydraulic drive unit can be controlled to output a changed hydraulic power. On the other hand, it is provided that for switching from the second operating mode to the first operating mode to at least partially compensate for a drop in force and/or an increase in speed of the piston-cylinder unit that occurs when switching over, the hydraulic drive unit can be controlled to output a changed hydraulic power.

Consequently, the change in speed or force of the piston-cylinder unit takes place in a controlled and regulated manner. In other words, switching between the operating modes is implemented via a switching element (e.g. via a proportional or control valve) and the drive source (hydraulic drive unit, e.g. in the form of a pump or also a proportional valve) is controlled in parallel in such a way that a predetermined speed and/or force profile can be driven without a noticeable shifting process.

Preferred embodiments of the present invention are set out in the dependent claims.

For general explanation it should be stated that the hydraulic power corresponds to a product of a hydraulic quantity delivered by the hydraulic drive unit per unit of time and the hydraulic pressure generated by the hydraulic drive unit. In other words, the hydraulic power is formed by the delivered hydraulic quantity and the hydraulic pressure.

[0018] In other words, the hydraulic power is made up of the speed or the quantity and the pressure. The hydraulic power itself is not determined or adjusted. Rather, the speed is set and the limits for the pressure are set. Conversely, the pressure can be set and the limits for the speed can be set.

A hydraulic fluid, in particular a hydraulic oil, can be used as the hydraulic medium.

It is provided for the hydraulic drive unit that it is connected to a hydraulic source. The hydraulic source can be in the form of a hydraulic tank, for example. In order to convey the hydraulic fluid, it is preferably provided that the hydraulic drive unit has a hydraulic pump and/or a proportional valve.

According to a preferred embodiment it is provided that the hydraulic drive unit - at least for switching between the operating modes - on the basis of a

predetermined performance profile can be controlled. This makes it possible for the piston-cylinder unit to be operable with a predetermined speed and/or force profile. Predetermined speed and/or force profiles can be stored in a memory of the control or regulation unit, for example.

For the operation of the drive device can be provided according to a first variant that in the first operating mode in a certain period of time (for example 0.05 to 0.7 seconds) before switching to the second operating mode, the hydraulic drive unit to output a reduced hydraulic Performance can be controlled in such a way that the hydraulic quantity delivered by the hydraulic drive unit drops from a constantly high level to a constantly low level, thereby reducing the speed of the piston-cylinder unit from a constantly high level to a constantly low level.

Furthermore, in this first variant, it is preferably provided that, preferably at the same time as switching from the first operating mode to the second operating mode, the hydraulic drive unit can be controlled in such a way that the hydraulic power of the hydraulic drive unit increases and at the same time that of the piston-cylinder -unit increases from a low level to a high level and the speed of the piston-cylinder unit remains constant at the low level.

For the operation of the drive device can be provided according to a second variant that the switching from the first operating mode to the second operating mode in the form of a gradual (for example 0.1 to 0.4 seconds long) switching takes place.

Furthermore, in this second variant, it is preferably provided that during the gradual switchover, the hydraulic drive unit for outputting the hydraulic power can be controlled in such a way that the hydraulic quantity delivered by the hydraulic drive unit initially increases from an initial level and then falls back to the initial level. during the gradual switching, at the same time the force exerted by the piston-cylinder unit increases and the speed of the piston-cylinder unit decreases.

According to a preferred exemplary embodiment, a detection device is provided for detecting the time of switching between the operating modes. This detection device can be integrated into the control or regulation unit or can be connected to it in terms of signals.

In order to achieve switching between the operating modes that is as smooth as possible, it is preferably provided that the hydraulic power output by the hydraulic drive unit can be changed as a function of the switching time recognized by the detection device.

Furthermore, it is preferably provided that the control or regulating unit is in signaling connection with the hydraulic drive unit and with the switching element. The hydraulic drive unit and the switching element are designed as separate components, which, however, can be controlled or regulated by the same control or regulating unit.

Protection is also sought for a molding machine, in particular an injection molding machine or transfer press, with a hydraulic drive device according to the invention.

The molding machine is preferably constructed to include an injection unit and a clamping unit. Such a molding machine may have one piston-cylinder unit for a particular component, or it may have multiple piston-cylinder units. For example, it is provided that an injection piston of the injection unit, a clamping force application device of the clamping unit, an express lifting device of the clamping unit or an ejector can be moved via the hydraulic drive device and its piston-cylinder unit(s)—preferably each.

According to a preferred exemplary embodiment, it is provided that the shaping machine has a machine controller, the control or regulating unit being integrated into the machine controller or being connected to the machine controller by means of signals

stands. This machine control can also have an operating unit with a screen and an input device for an operator.

In a method for operating a hydraulic drive device for a molding machine, in particular an injection molding machine or transfer press, with the features of the preamble of claim 11, the solution to the above-mentioned object is provided in that the hydraulic drive device is controlled in such a way that, for switching from first operating mode to the second operating mode to at least partially compensate for an increase in force and/or a drop in speed of the piston-cylinder unit that occurs when switching over, the hydraulic drive unit is actuated to output a changed (preferably reduced) hydraulic power and for a switchover from the second operating mode to the first operating mode for at least partially compensating for a drop in force and/or an increase in speed of the piston-cylinder unit that occurs when switching over, the hydraulic drive unit for outputting a changed (preferably e increased) hydraulic power is controlled.

Protection is also sought for a computer program product comprising instructions which, when a program is executed by a computing unit, cause the latter to execute the method according to the invention on a shaping machine.

Further details and advantages of the present invention are explained in more detail below on the basis of the description of the figures with reference to the exemplary embodiments illustrated in the drawings. Show in it:

Fig. 1 schematically shows a molding machine, Fig. 2 shows a force-speed-power diagram of the differential circuit, Fig. 3 shows a hydraulic circuit diagram of the hydraulic drive device,

4a+4b flow charts of the speed, hydraulic power and force according to a first exemplary embodiment,

5a+5b flowcharts of the speed, hydraulic power and force according to a second embodiment,

6a-6c different variants of a hydraulic circuit diagram of a hydraulic drive device and

[0041] FIG. 7 shows a hydraulic circuit diagram with a parallelism control of a plurality of piston-cylinder units.

A shaping machine 100 is shown schematically in FIG. This molding machine 100 has an injection unit 7 and a clamping unit 8 .

The injection unit 7 comprises an injection cylinder 72 and an injection piston 71 movably mounted in the injection cylinder 72. The injection piston 71 can be driven or moved via a hydraulic drive device 1, which is indicated only schematically.

The closing unit 8 is designed as a two-platen machine in the illustrated embodiment. Alternatively, the clamping unit can also be designed in the form of a tie-bar-less machine or as a vertical machine. In any case, the closing unit 8 comprises a movable mold mounting plate 84 and a stationary mold mounting plate 85, with bars 86 passing through these two plates. The mold halves of a shaping tool 87 are fastened to the mold clamping plates 84 and 85, with at least one cavity K being formed in the closed shaping tool 87. A liquid plastic starting material can be injected into this cavity K via the injection unit 7 .

An express lifting device 82 is indicated schematically in FIG. The Eilhubvorrichtung 82 has a schematically indicated piston-cylinder unit 3, which in turn is part of a hydraulic system

drive device 1 can be.

A closing force application device 81 is also shown schematically in FIG. This can be designed, for example, as a toggle lever system or as a plunger cylinder. With this closing force application device 81, a closing force can be applied when the shaping tool 87 is closed. This closing force application device 81 can also be driven by a hydraulic drive device 1 or can include it. In order to apply the closing force, it is also necessary for the bars 86 to be able to be locked in the area of the movable mold clamping plate 84 via locking devices 83 .

1 also shows an ejector 9 for ejecting a molded part that has hardened in the cavity K. FIG. It can be seen that this ejector 9 includes a piston-cylinder unit 3 of a hydraulic drive device 1 .

A machine control 10 is indicated schematically in FIG. As shown, this machine control 10 can include a screen 11 and an input device 12 . In addition, the machine control 10 has a memory 13 .

1 also shows a control or regulating unit 5 which is part of the hydraulic drive device 1 and is designed to control or regulate this hydraulic drive device 1 . In the exemplary embodiment shown, this control or regulation unit 5 is connected to the machine controller 10 in terms of signals. This control or regulation unit 5 has a memory 51 . For example, predetermined performance profiles for the hydraulic drive unit 2 can be stored in this memory 51 .

Before the details and components of the hydraulic drive device 1 are discussed, the principle of the differential circuit is explained with reference to FIG. The time in seconds s is plotted on the abscissa. The ordinate shows the hydraulic pressure p, the hydraulic quantity Q, the force F and the speed V. In terms of time, the hydraulic drive device 1 is initially operated in the first operating mode B1, in which the differential operation is active. The hydraulic quantity Q and the hydraulic pressure p are constant. The hydraulic power is therefore also constant. The speed Vprign is at a high level, while the force Fıow is at a low level. The vertical dashed line then illustrates the switchover from the first operating mode B1 to the second operating mode B2. In this second operating mode B2, the differential operation B1 is inactive. As can be seen in Figure 2, the velocity changes abruptly from the high level Vhriga to a low Viow, while the force also changes abruptly from the low level Fiow to a high level Frign. Meanwhile, the hydraulic quantity Q and the hydraulic pressure p remain the same.

In Fig. 3, a hydraulic drive device 1 is shown schematically, which has a hydraulic drive unit 2, a piston-cylinder unit 3, a hydraulic line system 4 and a control or regulating unit 5 has.

In the exemplary embodiment shown, the hydraulic drive unit 2 has a hydraulic pump 21 and a proportional valve 22 . The hydraulic medium is conveyed into the hydraulic line system 4 by the hydraulic drive unit 2 with a specific hydraulic power. This hydraulic power is controlled via the control or regulating unit 5 . For example, a type of performance profile can be stored in the memory 51 of the control or regulation unit 5 . Specifically, a quantity profile and/or a force or pressure profile can be stored.

The piston-cylinder unit 3 has a cylinder 31 and a piston 32 guided in the cylinder 31 . The piston 32 divides the space formed in the cylinder 31 into a rod-side chamber 3s and a piston-side chamber 3k.

The hydraulic line system 4 has a first connection point 41 for connection to the

hydraulic drive unit 2 on. In this case, the outlets of the proportional valve 22 form this first connection point 41. The hydraulic line system 4 has a second connection point 42 for connection to the rod-side chamber 3s of the piston-cylinder unit 3 and a third connection point 43 for connection to the piston-side chamber 3k of the piston -cylinder unit 3 on. Furthermore, the hydraulic line system 4 has a circulating line 44 connecting the second connection point 42 to the third connection point 43 . In addition, the hydraulic line system 4 has a switching element 45 for setting a differential operation. In a differential position D of the switching element 45, differential operation can be built up via the circulating line 44. The switching element 45 can be designed as a proportional or control valve.

The control or regulating unit 5 is connected to the hydraulic drive unit 2 and to the switching element 45 in terms of signals (see dashed line). Both the hydraulic drive unit 2 and the switching element 45 can be controlled or regulated via the control or regulating unit 5 .

When switching over the differential circuit, a movement of the piston-cylinder unit 3 should be implemented in such a way that there is no sudden change in speed or force, but this happens in a controlled and regulated manner. This is achieved in that the changeover is implemented via the switching element 45 and the hydraulic drive unit 2 is controlled or regulated in parallel in such a way that a predetermined speed and/or force profile can be driven without a noticeable switching process.

Specifically, it is provided that for switching from the first operating mode B1 to the second operating mode B2 to at least partially compensate for an increase in force and/or a drop in speed of the piston-cylinder unit 3 that occurs when switching over, the hydraulic drive unit 2 is used to output a changed, preferably reduced, hydraulic power can be controlled. This means that both the switching element 45 and the hydraulic drive unit 2 are actuated accordingly via the control or regulating unit 5 . For switching from the second operating mode B2 to the first operating mode B1, in order to at least partially compensate for a drop in force and/or an increase in speed of the piston-cylinder unit 3 that occurs during the switchover, provision is made for the hydraulic drive unit 2 to output a changed, preferably increased, hydraulic performance is controllable.

[0058] Finally, FIG. 3 shows a detection device 6 for detecting the time of switching between the operating modes B1 and B?2 in dashed lines. The detection device has at least one pressure sensor and/or a distance or displacement sensor (not shown). This detection device 6 is connected to the control or regulating unit 5, and this detection device 6 can be used to detect the changeover point as a function of time, as a function of distance, as a function of pressure, or via a learning process. The hydraulic power output by the hydraulic drive unit 2 can be variable as a function of the switchover point in time detected by the detection device 6 .

4a shows a speed-time diagram, the time tin seconds s being plotted on the abscissa, while the speed V and the hydraulic quantity Q are plotted on the ordinate. The dot-dash line illustrates the actuation of switching element 45.

In Fig. 4b - matching Fig. 4a and with the same timing - a force-time diagram is shown, the time t in seconds s being plotted on the abscissa, while the force F is plotted on the ordinate. The lower dashed line in FIG. 45 indicates which maximum force F+ would be possible based on the switching position of the switching element 45 in the first operating mode B1. This maximum force F+ results from the product of the area difference (A2 - A1) of the piston 32 and the hydraulic pressure p. The upper dashed line in FIG. 4b indicates which maximum force F2 would be possible based on the switching position of the switching element 45 in the second operating mode B2. This maximum force F> results from the product of the area A2 of the piston 32 and the hydraulic pressure p. In addition, the individual phases of the movement of the hydraulic drive device 1 are entered in FIG. 45 below, with these phases for both

The diagrams according to FIGS. 45 and 4a apply.

In the first phase (fast driving phase i), the piston 32 is moved in the differential mode B1 at a high speed Vprign. The hydraulic quantity delivered is also at a high level Qhnign. The switching element 45 is controlled in such a way that the hydraulic drive unit 1 is operated in the first operating mode B1 (see dot-dash line). The force is at a low level Fiow far below the maximum force F+.

In the second phase ii, the speed V is reduced in a targeted manner by the hydraulic quantity Q being reduced. The hydraulic drive unit 2 is therefore controlled in such a way that a low hydraulic power is made available, as a result of which the speed V is reduced. It can be seen that in this second phase ii the force F is already increasing slightly.

In the third phase iii, the hydraulic quantity supplied has reached a constant low level Qww, as a result of which the speed has also reached a constant low level Viow.

In other words, in the second phase ii up to the beginning of the third phase ili, the hydraulic drive device 1 is controlled in such a way that in the first operating mode B1 in a certain period of time before switching to the second operating mode B2, the hydraulic drive unit 2 to output a reduced hydraulic power can be controlled, the hydraulic quantity Q delivered by the hydraulic drive unit 2 dropping from a constantly high level Qhign to a constantly low level Qiw and thereby the speed V of the piston-cylinder unit 3 from a constantly high level Vhrign to a constant low level View Sinks.

[0065] This is followed by the fourth phase iv, in which there is a controlled switchover from differential operation B1 to operating mode B2 with increased force. In this fourth phase iv, switching element 45 switches from the first operating mode B1 to the second operating mode B2 (differential switching is deactivated). In addition, the supplied hydraulic quantity Q or the hydraulic power is increased again, which does not lead to an increase in speed V, but to an increase in force F. Specifically, the force F already exceeds the maximum force F+ in the first operating mode B1.

In the fifth phase v, the hydraulic quantity has again reached the high level Qnign. The speed remains at a low level Viow. The force approaches the maximum force F>2.

In other words, it is provided in the fourth phase iv and fifth phase v that, preferably at the same time as switching from the first operating mode B1 to the second operating mode B2, the hydraulic drive unit 2 can be controlled in such a way that the hydraulic power of the hydraulic drive unit 2 increases and at the same time the force F exerted by the piston-cylinder unit 3 increases from a low level Fıw to a high level Fhkigh and the speed V of the piston-cylinder unit 3 remains constant at the low level Viow.

Finally, the sixth phase vi follows (force control phase). In this force control phase, the force F (e.g. the closing force during injection) is kept at a constantly high level close to the maximum force F». The speed V quickly decreases towards zero. The supplied hydraulic quantity Q also decreases rapidly.

In principle, the same values as in the diagrams of FIGS. 4a and 4b are again entered in the diagrams shown in FIGS. 5a and 5b. However, FIGS. 5a and 5b show another embodiment.

The first phase a illustrated in FIGS. 5a and 5b corresponds to the high-speed phase, ie the differential operation B1, and is to be equated with the first phase i according to FIGS. 4a and 4b.

The switchover from the first operating mode B1 to the second operating mode B2 already takes place in the second phase b. The differential mode B1 is therefore deactivated. This switchover takes place during the increase in force, with the switchover from the first operating mode B1 to

the second operating mode B2 takes place in the form of a gradual switching. At the same time, the speed drops from the high Virign level to the low Viow level. The hydraulic quantity Q or hydraulic power remains essentially constant.

In other words, it is provided in the second phase b that, during the gradual switchover, the hydraulic drive unit 2 can be controlled to output the hydraulic power in such a way that the hydraulic quantity Q delivered by the hydraulic drive unit 2 initially increases from an initial level Qsıar and then again to the initial level Qstart sinks, with the force F exerted by the piston-cylinder unit 3 simultaneously increasing and the speed V of the piston-cylinder unit 3 decreasing during the gradual switchover.

Then follows the third phase c, which is to be equated with the fifth phase v. The force F almost reaches the maximum force F2. The speed V remains constant at a low level Viow-

Finally, the fourth phase d is reached, which corresponds to the force control phase according to the sixth phase vi.

6a to 6c show different variants of how a hydraulic drive device 1 can be constructed hydraulically with a differential circuit.

In Fig. 6a the structure is very similar to that in Fig. 3. It is shown that the hydraulic pump 21 is driven by a motor M. In addition, the hydraulic power (see arrow) and also the speed V of the piston 32 can be seen.

In Fig. 6b the switching element 45 is positioned differently.

In FIG. 6c, the lines of the hydraulic line system 4 are partially arranged or connected differently.

7 shows a hydraulic drive device 1 with a plurality of piston-cylinder units 3 which are arranged in a parallelism control. A proportional valve 22 and a switching element 45 as well as the corresponding lines of the hydraulic line system 4 are provided for each piston-cylinder unit 3 . The control or regulation unit 5 is not specifically shown.

REFERENCE LIST:

1 hydraulic drive device 2 hydraulic drive unit 21 hydraulic pump

22 proportional valve

3 piston-cylinder unit

31 cylinders

32 pistons

3s rod side chamber

3k piston side chamber

4 hydraulic line system

41 first junction

42 second connection point

43 third connection point 44 circulation line

45 switching element

5 control or regulation unit 51 memory 6 detection device

7 injection unit

71 injection piston

72 injection cylinder

8 locking unit

81 Closing force application device 82 Rapid lifting device

83 locking device

84 movable platen 85 fixed platen 86 bars

87 shaping tool

88 machine frames

9 ejectors

10 machine control

11 screen

12 input device

100 shaping machine

Qp hydraulic power

F force

Fiow low level of force

Frign high level of vigor

Fı maximum force in B1

F2 maximum force in B2

V speed

Vrign high speed level Viow low speed level Q hydraulic quantity

Qnion high level of hydraulic volume

Qwow low level of hydraulic flow

Qstart initial level of hydraulic quantity

D differential position

B1 first mode of operation

B2 second mode of operation

K cavity

Ss seconds

p hydraulic pressure

t time

i first phase (fast driving phase)

il second phase (phase of reduction of Q)

il third phase (constant speed phase)

IV fourth phase (controlled switching phase) V fifth phase (constant speed and increased force phase) vi sixth phase (force control phase)

A1 Area of the piston A2 Area of the piston

a first phase (fast driving phase) b second phase

c third phase

d fourth phase (force control phase) M motor

Claims (1)

patent claims 1. Hydraulic drive device (1) for a shaping machine (100), in particular an injection molding machine or transfer press, with - a hydraulic drive unit (2) for generating hydraulic power, - a piston-cylinder unit (3), - a hydraulic drive unit ( 2) with the piston-cylinder unit (3) connecting hydraulic line system (4), in which hydraulic power can be adjusted via the hydraulic drive unit (2), the hydraulic line system (4) * having a first connection point (41) for connection with the hydraulic drive unit (2), * a second connection point (42) for connection to a rod-side chamber (3s) of the piston-cylinder unit (3), * a third connection point (43) for connection to a piston-side chamber (3k) of the piston-cylinder unit (3), * a circulation line (44) connecting the second connection point (42) to the third connection point (43) and * at least one switching element (45) for setting a differential mode, wherein in a differential position (D) of the switching element (45) the differential mode can be built up via the circulation line (44), and - a control or regulating unit (5) for controlling or regulating the hydraulic drive device (1), wherein the hydraulic drive unit (2) can be controlled via the control or regulating unit (5) to generate a specific hydraulic power and wherein the switching element (45 ) can be controlled via the control or regulation unit (5), wherein in a first operating mode (B1) - in which the differential operation is active - the Actuate the piston-cylinder unit (3) with low force (F) and high speed (V) is erbar and in a second operating mode (B2) - in which the differential mode is inactive is - the piston-cylinder unit (3) with high force (F) and low speed (V) is controllable, where - for switching from the first operating mode (B1) to the second operating mode (B2) to at least partially compensate for an increase in force and/or a drop in speed of the piston-cylinder unit (3) that occurs when switching over, the hydraulic drive unit (2) to output a changed hydraulic power is controllable and - for switching from the second operating mode (B2) to the first operating mode (B1) to at least partially compensate for a drop in force and/or an increase in speed of the piston-cylinder unit (3) that occurs when switching over, the hydraulic drive unit (2) to output a changed hydraulic power can be controlled characterized in that - the control or regulating unit (5) is designed to control the hydraulic drive unit (2) in the first operating mode (B1) in a specific period of time before switching to the second operating mode (B2) to output a reduced hydraulic power such that the The hydraulic quantity (Q) delivered by the hydraulic drive unit (2) drops from a constantly high level (Qhign) to a constantly low level (Qww) and as a result the speed (V) of the piston-cylinder unit (3) drops from a constantly high level (Vhrign) to a constantly low level (Viow) and that thereafter, preferably at the same time as switching from the first operating mode (B1) to the second operating mode (B2), the hydraulic power of the hydraulic drive unit (2) increases and at the same time that of the Piston-cylinder unit (3) exerted force (F) increases from a low level (Fıow) to a high level (Fhkign) and the speed (V) of the piston-cylinder unit (3) remains constant at a low level (Vw) (Fig. 4a,b) or 10 11. Austrian AT 524 160 B1 2022-06-15 - the switching from the first operating mode (B1) to the second operating mode (B2) takes place in the form of a gradual switchover, the control or regulating unit (5) being designed to use the hydraulic drive unit (2) to output the hydraulic To control the power in such a way that the hydraulic quantity (Q) delivered by the hydraulic drive unit (2) initially increases from a starting level (Qstart) and then falls back to the starting level (Qstart), with the simultaneous switching from the piston-cylinder Unit (3) exerted force (F) increases and the speed (V) of the piston-cylinder unit (3) decreases (Fig. 5a, b). Drive device according to Claim 1, characterized in that the hydraulic drive unit (2) has a hydraulic pump (21) and/or a proportional valve (22). Drive device according to Claim 1 or 2, characterized in that the hydraulic drive unit (2) - at least for switching between the operating modes (B1, B2) - can be controlled on the basis of a predetermined performance profile. Drive device according to one of Claims 1 to 3, characterized by a detection device (6) for detecting the time of switching between the operating modes (B1, B2). Drive device according to Claim 4, characterized in that the hydraulic power output by the hydraulic drive unit (2) can be changed as a function of the changeover time detected by the detection device (6). Drive device according to one of Claims 1 to 5, characterized in that the control or regulating unit (5) is in signaling connection with the hydraulic drive unit (2) and with the switching element (45). Drive device according to one of Claims 1 to 6, characterized in that the drive device (1) comprises a plurality of piston-cylinder units (3) which can be controlled in parallel operation via the control or regulating unit (5) and which are each in one of the both operating modes (B1, B2) can be operated. Shaping machine (100), in particular an injection molding machine or transfer press, with a hydraulic drive device (1) according to one of Claims 1 to 7. Shaping machine according to claim 8, with an injection unit (7) and a clamping unit (8), wherein via the hydraulic drive device (1) and its piston-cylinder unit (3) an injection piston (71) of the injection unit (7), a clamping force application device (81) the closing unit (8), an express lifting device (82) of the closing unit (82) or an ejector (9) can be moved. Shaping machine according to Claim 8 or 9, characterized in that the shaping machine (100) has a machine controller (10), the control or regulating unit (5) being integrated into the machine controller (10) or having a signal connection with the machine controller (10). stands. Method for operating a hydraulic drive device (1), in particular according to one of Claims 1 to 7, for a shaping machine (100), in particular an injection molding machine or transfer press - a hydraulic drive unit (2) for generating hydraulic power, - a piston-cylinder unit (3), - a hydraulic line system (4) connecting the hydraulic drive unit (2) to the piston-cylinder unit (3), in which hydraulic power can be adjusted via the hydraulic drive unit (2), the hydraulic line system (4) having * a first connection point (41) for connection to the hydraulic drive unit (2), * a second connection point (42) for connection to a rod-side chamber (3s) of the piston-cylinder unit (3), * a third connection point (43) for connection to a piston-side chamber (3k) of the piston-cylinder unit (3), * a circulation line (44) connecting the second connection point (42) to the third connection point (43) and * at least one switching element (45) for setting a differential mode, wherein in a differential position (D) of the switching element (45) the differential mode can be built up via the circulation line (44), and - a control or regulating unit (5) for controlling or regulating the hydraulic drive device (1), the hydraulic drive unit (2) being controlled via the control or regulating unit (5) to generate a specific hydraulic power and the switching element (45 ) is activated via the control or regulating unit (45), with the steps: - Operating the hydraulic drive device (1) in a first operating mode (B1), in which the differential operation is active, the piston-cylinder unit (3) being controlled with low force (F) and at high speed (V), and - Operating the hydraulic drive device (1) in a second operating mode (B2) in which the differential operation is inactive, the piston-cylinder unit (3) being controlled with high force (F) and at low speed (V), wherein the hydraulic drive device (1) is controlled in such a way that - for switching from the first operating mode (B1) to the second operating mode (B2) to at least partially compensate for an increase in force and/or a drop in speed of the piston-cylinder unit (3) that occurs when switching over, the hydraulic drive unit (2) to output a changed hydraulic power is controlled and - for switching from the second operating mode (B2) to the first operating mode (B1) to at least partially compensate for a drop in force and/or an increase in speed of the piston-cylinder unit (3) that occurs when switching over, the hydraulic drive unit (2) to output a changed hydraulic power is controlled characterized in that - in the first operating mode (B1) in a certain period of time before switching to the second operating mode (B2), the hydraulic drive unit (2) is controlled to output a reduced hydraulic power in such a way that the hydraulic quantity (Q ) from a constantly high level (Qnign) to a constantly low level (Qıiew) and thereby the speed (V) of the piston-cylinder unit (3) from a constantly high level (Virign) to a constantly low level (View) and that thereafter, preferably at the same time as switching from the first operating mode (B1) to the second operating mode (B2), the hydraulic power of the hydraulic drive unit (2) increases and at the same time the force exerted by the piston-cylinder unit (3) ( F) increases from a low level (Fıow) to a high level (Fkign) and the speed (V) of the piston-cylinder unit (3) remains constant at the low level (View). bt (Fig. 4a,b) or - Switching from the first operating mode (B1) to the second operating mode (B2) takes place in the form of a gradual switchover, with the hydraulic drive unit (2) for outputting the hydraulic power being controlled during the gradual switchover in such a way that the hydraulic power generated by the hydraulic drive unit ( 2) The delivered hydraulic quantity (Q) first rises from an initial level (Qsıarn) and then falls back to the initial level (Qstart), with the force (F) exerted by the piston-cylinder unit (3) simultaneously increasing during the gradual switchover and the speed (V) of the piston-cylinder unit (3) decreases (Fig. 5a,b). 12. Computer program product comprising instructions which, when a program is executed by a control or regulating device, cause the latter to carry out the method according to claim 11 on a shaping machine (100) according to one of claims 8 to 10. 7 sheets of drawings