DE102020102378A1 - Drive device for a molding machine - Google Patents

Abstract

Drive device (1) for a molding machine (2), in particular for an injection molding machine, with at least one hydraulically driven pressure pad (3) via which a spar (4) or a movable platen (5) of the molding machine (2) can be moved to apply the clamping force, a conveying device (6) for conveying a hydraulic fluid, the conveying device (6) having a conveying cylinder (61), a conveying chamber (62) formed in the conveying cylinder (61) and filled with hydraulic fluid and a conveying piston (63) movable in the conveying chamber (62) , wherein the delivery piston (63) divides the delivery space (62) into a first space (64) and a second space (65), and a hydraulic line system (7) filled with hydraulic fluid, via which the delivery device (6) with the pressure cushion ( 3) is connected, wherein a shut-off device (8) for interrupting the connection of the pressure pad (3) to the conveying device (6) and a first space (64) with d A connecting line (70) connecting the second space (65) for conveying hydraulic fluid between the spaces (64, 65) when the connection between the pressure pad (3) and the conveying device (6) is interrupted by the shut-off device (8).

Description

The present invention relates to a drive device for a shaping machine, in particular for an injection molding machine, with at least one hydraulically driven pressure cushion, via which a spar or a movable platen of the shaping machine can be moved for applying clamping force, a conveying device for conveying a hydraulic fluid, the conveying device being a conveying cylinder, has a delivery chamber formed in the delivery cylinder and filled with hydraulic fluid and a delivery piston movable in the delivery chamber, the delivery piston dividing the delivery chamber into a first room and a second room, and a hydraulic line system filled with hydraulic fluid, via which the delivery device is connected to the pressure cushion. In addition, the invention relates to a molding machine with such a drive device.

A wide variety of drive devices have already been implemented on the closing side of the shaping machine in order to carry out the closing and opening movement of the movable platen. The closing movement is divided into two sections, namely the rapid stroke, in which the platen covers a relatively large distance with relatively little force, and the closing force build-up, in which the platen hardly covers a path, and the platen by a relatively high force are pressed together.

The use of hydraulically operated pressure cushions has been known for many years, particularly for carrying out the clamping force build-up. The rapid stroke can either also be carried out via these pressure cushions or a rapid stroke device separate from the pressure cushion can be provided.

An example of the use of pressure cushions for the clamping force build-up in a vertical clamping unit of a shaping machine is given in FIG DE 10 2016 006 108 A1 forth.

The EP 1 388 404 B shows a hydraulic unit for an injection molding machine with a drive, which is operatively connected to a functional unit via an adjusting mechanism and a hydraulic power converter. An actuating movement of the input cylinder can be converted into a corresponding movement of the output cylinder. To compensate for a leak between the pressure chambers, a referencing device is provided, by means of which the pressures can be corrected. A directional valve is provided to connect the inlet and outlet lines.

The EP 1 331 079 B1 shows a two-platen locking system of an injection molding machine, wherein double-acting and stored in the pressure cylinder closing pressure pistons are assigned to the fixed platen. The closing of the clamping unit in rapid traverse is triggered by a spindle, which is driven by a drive motor via a toothed belt, whereby various valves are switched accordingly. For the build-up of clamping force, by turning the spindle further in the closing direction, hydraulic fluid is fed from a pressure chamber through an open valve into the closing chambers of the closing pressure cylinder. After this valve is closed, the desired shooting pressure is locked in for the duration of the spraying process, the pressurized hydraulic fluid acting in the closing pressure chambers on the annular piston surfaces of the four closing pressure pistons. A disadvantage of this device is that the spindle is lubricated directly via the hydraulic oil, since hydraulic oil has an unfavorable viscosity for the lubrication. As a result, the wear on the spindle is very high and the service life is very short, which is why such a spindle often has to be replaced, which in turn is complex. Furthermore, it is disadvantageous that hydraulic oil has to be supplied to the closing force side of the chamber of the closing pressure piston via the rapid stroke, which drastically increases the volume required. However, this must then be compressed again via the spindle, which requires a rather large compression stroke, which in turn leads to a large overall length. In addition, a tank is required in this device, which in turn requires a lot of installation space. The long lines and the tank also multiply the amount of hydraulic oil required in the system.

The EP 2 242 633 B1 shows a linear drive for generating an actuating movement and for applying a large holding force. It is similarly disadvantageous as with the above-mentioned document that, on the one hand, a tank is also necessary here, and on the other hand that the spindle is lubricated directly in the unfavorable hydraulic oil. It is also disadvantageous that all the force has to be absorbed directly by the spindle. This document also shows a suboptimal combination of drive power and the required installation space.

At the outset, those movements (rapid stroke and closing force build-up) that - together with the opening - are carried out during each shaping cycle were described in more detail. However, there are also movements that are not carried out in every shaping cycle, but that are much less frequent. One such movement is the mold height adjustment. This is usually necessary when a new mold is mounted on the platen. Depending on the Height of the mold, there is a changed closed position. This means that, depending on the mold height, the mold mounting plates are at different distances from each other in the closed position. In other words, in a spar machine, the relative position of the movable platen relative to the spar is changed, so that both the starting position before closing and the position when the clamping force is applied are shifted in accordance with the change in form height. Various solutions are already known for carrying out a corresponding mold height adjustment when changing tools.

For example, the EP 1 321 272 B1 a device for adjusting the installation height of a tool, with each spar an adjustment element is positively connected, which are axially adjustable relative to the spar via a central drive. The adjusting elements can be locked by means of a locking device. The locking device is designed as a displaceable piston.

The DE 10 2015 011 425 A1 shows a clamping unit for a molding machine with a mold height adjustment device.

Both documents show devices that are relatively complex. This means that for the relatively rare tool changes, very complex additional components and structures are necessary.

The object of the present invention is therefore to create a drive device which is improved compared to the prior art. In particular, the disadvantages mentioned should be eliminated. Particularly preferably, the drive device should be made simpler, less expensive and / or smaller and still be able to carry out the necessary movements.

This is achieved by a drive device with the features of claim 1. Accordingly, it is provided according to the invention that the drive device has a shut-off device for interrupting the connection of the pressure pad to the conveying device and a connecting line connecting the first space to the second space for conveying hydraulic fluid between the spaces when the pressure pad is interrupted by the shut-off device to the conveying device.

With the present invention it is possible that the starting position of the pressure pad is changed by the conveyor device. This means that the mold height to which the drive device is designed is adjusted. The conveyor device is not only used for clamping force application, but is also used for spar positioning. The conveyor device forms a mold height adjustment device together with the pressure cushion. A change in the spar position can thus be carried out in a simple manner during a tool change. The solution is also very compact.

Preferred embodiments of the present invention are specified in the dependent claims.

The pressure pad is designed as a piston-cylinder unit for simple operation. According to a preferred exemplary embodiment, it is provided that the pressure cushion has a cushion cylinder, a pressure cushion space formed in the cushion cylinder and filled with hydraulic fluid and a cushion piston movable in the pressure cushion space, the cushion piston dividing the pressure cushion space into a closing pressure space and an opening pressure space.

Hydraulic fluid is a fluid that is required to transfer energy (volume flow, pressure) in hydraulic systems in fluid technology. Hydraulic fluids or corresponding mixtures of a liquid and gas fall under the term hydraulic fluid. A hydraulic oil is preferably used as the hydraulic fluid.

It should generally be stated that the delivery device is designed as a piston pump.

The first space and / or the second space of the delivery space can be designed as a pressure space. This means that this room is pressurized with (hydraulic) pressure.

The lines of the hydraulic line system can be of any design as long as sufficient pressurization of the conveying device and the pressure pad is possible. The lines of the hydraulic line system also include the terms hose, bore, pipe, etc.

It is preferably provided that the hydraulic line system has a first hydraulic line, which connects the closing pressure chamber of the pressure cushion to the first chamber of the conveying device. In addition, it can be provided that the hydraulic line system has a second hydraulic line, which connects the opening pressure space of the pressure pad with the second space of the conveying device. In addition, it can be provided that the hydraulic line system has a connecting line which connects the first hydraulic line and the second hydraulic line.

Furthermore, it can preferably be provided that in the first hydraulic line between a branch to the connection line and the closing pressure chamber is arranged a first switching element, preferably for performing a delivery device empty stroke, and / or a second switching element, preferably for performing a delivery device empty stroke, is arranged in the second hydraulic line between a branch to the connection line and the opening pressure chamber is

It is particularly preferably provided that the connecting line extends from the part of the first hydraulic line which extends from the first pressure chamber to the branch to the connecting line, from the connecting line and from the part of the second hydraulic line which extends from the branching of the connecting line to the second pressure chamber. put together.

In order to make it possible to shut off, it is preferably provided that the first switching element and the second switching element can be brought into a closed position, preferably for carrying out an empty device lifting stroke of the conveying piston of the conveying device. Thus, the first switching element and the second switching element together form the shut-off device.

Each switching element is preferably designed as a fluidic switching element. Specifically, a switchable valve or a cartridge valve can be used as the switching element.

In order to carry out a pressure cushion stroke, it can preferably be provided that a third switching element is arranged in the connecting line. It is preferably provided that the first switching element and the second switching element can be brought into an open position and the third switching element can be brought into a closed position in order to carry out a mold height adjustment stroke of the cushion piston of the pressure cushion.

In order to be able to dispense with a tank, it is preferably provided that the pressure cushion chamber, the delivery chamber and the hydraulic line system form a closed hydraulic circuit.

Furthermore, it is preferably provided that the hydraulic line system, preferably in the area of the connecting line, is connected to a storage device, preferably a bladder accumulator. Such a hydraulic accumulator serves to compensate for the (minimum) differential volume due to the compression of the hydraulic fluid.

Especially if a storage device is provided, it makes sense for the storage device to be connected to the connecting line via a branch line branching off the connecting line, the connecting line between the branch line and the first hydraulic line preferably being used to carry out the mold height adjustment stroke into a closed position bringable - the third switching element is arranged and a fourth switching element is arranged in the connecting line between the branch line and the second hydraulic line - preferably bringable into a closed position for performing the mold height adjustment stroke.

Furthermore, it is preferably provided that the conveyor device is designed as a two-stage force converter. It is preferably provided that the second pressure chamber is formed in two parts - with a partial space that is annular in cross-section and axially on the outside and with a separate, axially inner partial space that is separate therefrom.

Especially in the case of a conveyor device designed as a two-stage force booster, it is useful if the first hydraulic line has a first branch line and a second branch line, the first branch line being connected to the axially outer, annular partial space and the second branch line being connected to the axially inner partial space. It can also preferably be provided that a fifth switching element is arranged in the second branch line and a sixth switching element is arranged in the first branch line.

According to a preferred embodiment, it is provided that the conveyor device can be driven by an electric drive. In particular, it is provided that the delivery piston can be moved by the electric drive relative to the delivery cylinder, preferably linearly.

Protection is also sought after for a molding machine, in particular an injection molding machine, with a drive device according to the invention. It is preferably provided that the molding machine has an injection unit and a clamping unit, the clamping unit having a machine bed, a fixed mold mounting plate connected to the machine bed and a mold mounting plate movably mounted on the machine bed, the movable mold mounting plate being drivable by the drive device.

There are two fundamentally common ways of designing molding machines, namely as two or three-plate machines with bars or as tie bar-less machines.

In the first variant, it is provided that the clamping unit has four spars which pass through the mold mounting plates, each spar being connected to a cushion piston of a pressure cushion of the drive device.

In the second variant, it is provided that the clamping unit is designed without a tie bar, the cushion piston being connected to the movable platen and the cushion cylinder being connected to an end plate of the clamping unit attached to the machine bed or being formed in this end plate.

• 1 in einer schematischen Seitenansicht eine Formgebungsmaschine in Form einer Holmmaschine mit einer Antriebsvorrichtung,
• 2 in einer schematischen Seitenansicht eine Formgebungsmaschine in Form einer holmlosen Maschine mit einer Antriebsvorrichtung,
• 3 schematisch im Detail eine Antriebsvorrichtung samt Fördervorrichtung, Hydraulikleitungssystem und Druckkissen,
• 4 die Schaltstellung der Antriebsvorrichtung beim ersten Leerhub des Formteilhubs,
• 5 die Schaltstellung der Antriebsvorrichtung beim ersten Verstellhub des Formteilhubs,
• 6 die Schaltstellung der Antriebsvorrichtung beim zweiten Leerhub des Formteilhubs,
• 7 die Schaltstellung der Antriebsvorrichtung beim zweiten Verstellhub des Formteilhubs,
• 8 die neue Ausgangsstellung nach Beendigung des Formteilhubs,
• 9 eine Schaltstellung der Antriebsvorrichtung beim Positions-Toleranzausgleich,
• 10 die Schaltstellung der Antriebsvorrichtung beim Aufbau der Schließkraft,
• 11 die Schaltstellung der Antriebsvorrichtung beim Halten der Schließkraft,
• 12 die Schaltstellung der Antriebsvorrichtung beim Verdichten für den Sch ließkraftabbau
• 13 die Schaltstellung der Antriebsvorrichtung beim Schließkraftabbau,
• 14 die Schaltstellung der Antriebsvorrichtung bei der Rückstellung der Holme bzw. der Übertragungsstange,
• 15 die Ausgangsstellung der Antriebsvorrichtung,
• 16 die Schaltstellung der Antriebsvorrichtung bei Aufbringung einer erhöhten Öffnungskraft,
• 17 eine schematische Darstellung der Antriebsvorrichtung mit einer Fördervorrichtung in Form eines einstufigen Druckübersetzers,
• 18 die Antriebsvorrichtung mit einer im Kissenkolben angeordneten Fördervorrichtung in Form eines einstufigen Druckübersetzers und
• 19 die Antriebsvorrichtung mit einer im Kissenkolben angeordneten Fördervorrichtung in Form eines zweistufigen Druckübersetzers.

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

• 1 a schematic side view of a shaping machine in the form of a spar machine with a drive device,
• 2nd a schematic side view of a shaping machine in the form of a tie bar-less machine with a drive device,
• 3rd schematically in detail a drive device including conveyor, hydraulic line system and pressure pad,
• 4th the switching position of the drive device during the first idle stroke of the molding stroke,
• 5 the switching position of the drive device during the first adjustment stroke of the molding stroke,
• 6 the switching position of the drive device during the second idle stroke of the molding stroke,
• 7 the switching position of the drive device during the second adjustment stroke of the molding stroke,
• 8th the new starting position after the molding stroke has ended,
• 9 a switch position of the drive device in position tolerance compensation,
• 10th the switching position of the drive device when the closing force is built up,
• 11 the switching position of the drive device when holding the closing force,
• 12th the switching position of the drive device during compression for the closing force reduction
• 13 the switching position of the drive device when the clamping force is reduced,
• 14 the switching position of the drive device when resetting the spars or the transmission rod,
• 15 the starting position of the drive device,
• 16 the switching position of the drive device when an increased opening force is applied,
• 17th 1 shows a schematic representation of the drive device with a conveyor device in the form of a single-stage pressure intensifier,
• 18th the drive device with a conveyor device arranged in the cushion piston in the form of a single-stage pressure intensifier and
• 19th the drive device with a conveyor device arranged in the cushion piston in the form of a two-stage pressure intensifier.

In 1 is a schematic side view of a molding machine 2nd with an exemplary drive device 1 shown. In this case, the molding machine 2nd as a two-platen machine with bars 4th educated. The molding machine 2nd has the clamping unit as the main components 12th and the injection unit 11 on.

The injection unit 11 is only shown schematically. With the injection unit 11 can be liquid material, e.g. B. plastic or metal melt, in a molding tool 16 trained cavity are introduced. In the cavity, the liquid material initially hardens into a shaping part, which then emerges from the shaping tool 16 is removed, in particular ejected.

The clamping unit 12th has a machine bed 13 (also called frame), one with the machine bed 13 firmly connected fixed platen 14 and the one on the machine bed 13 movably mounted platen 5 on. In addition, the locking unit 12th the spars 4th on which the two mold platens 5 and 14 push through. In the area of the movable platen 5 are locking devices 17th arranged which the spars 4th at least partially surrounded axially. With these locking devices 17th becomes the platen 5 with the molding tool closed 16 on the bars 4th fixed or held positively or non-positively. In the locking position of the locking device 17th the application of closing force is made possible. The locking devices 17th can each have half shells 17a and 17b (also called locking nuts), which on the bars 4th are positively or non-positively connectable, preferably clampable. On the two platen 5 and 14 is a half of each mold 16a and 16b assembled. Together they form the two mold halves 16a and 16b the shaping tool 16 . In the closed state is in the molding tool 16 at least one cavity is formed (not shown).

The clamping unit 12th has a drive device 1 with which the mold clamping plates 5 and 14 and thus also the mold halves 16a and 16b are movable relative to each other. The Drive device 1 can be designed such that it has its own rapid lifting device for carrying out the rapid stroke (relatively long distance with relatively little force). This rapid lifting device can be designed, for example, in the form of a spindle drive or in the form of a toggle lever system. Such a rapid lifting device can be in the (left-hand) area of the movable platen 5 be arranged and this relative to the fixed platen 14 move. In 1 no rapid lifting device is shown.

The drive device 1 also features multiple pressure pads 3rd to apply clamping force. A pressure cushion is described in more detail below as an example. The pressure pad 3rd has a pillow cylinder 30th on which with the fixed platen 14 connected is. The pressure pad 3rd can, for example, on the fixed platen 14 be attached or integrated into this. In the pillow cylinder 30th is a pressure cushion room 31 trained, which is filled with hydraulic fluid (e.g. hydraulic oil). In the pressure cushion room 31 is a pillow piston 32 mounted linearly movable. The pillow piston 32 divides the pressure cushion area 31 in a closing pressure room 33 and in an opening pressure chamber 34 . The pillow piston 32 is with a spar 4th connected. The pressure pad 3rd stands over a hydraulic line system 7 with a conveyor 6 in connection. The pressure pad 3rd forms together with the hydraulic line system 7 and the conveyor 6 the drive device 1 . If no separate rapid lifting device is provided, this drive device is used 1 both the rapid stroke and the clamping force application were carried out. The conveyor 6 is used to convey hydraulic fluid from and to the pressure cushion 3rd . The conveyor 6 has a feed cylinder 61 , one in the feed cylinder 61 trained funding room 62 and one in the funding room 62 movable delivery piston 63 on. The delivery piston 63 divides the funding area 62 in a first room 64 and into a second room 65 . Because in this case the conveyor 6 is designed as a two-stage power converter, the first room 64 an axially outer subspace 66 and an axially inner (smaller) subspace 67 on. The delivery piston 63 is with a conveyor bar 68 connected which is the first room 64 into the two subspaces 66 and 67 divided. Via a drive rod 69 is the delivery piston 63 with an electric drive (shown schematically) 10th connected. About the electric drive 10th is the delivery piston 63 in the feed cylinder 61 movable in translation. The electric drive 10th can, for example, be designed as a rotating hollow shaft motor, which has the drive rod, which is partially designed as a spindle, via a spindle nut 69 drives linearly. The position of the conveyor 6 can be chosen freely. The conveyor 6 can, as shown, somewhere separate from the pressure pad 3rd be arranged. The conveyor 6 but can also in the fixed platen 14 be integrated or in the pressure pad 3rd be integrated.

In 2nd is the molding machine 2nd designed as a tie bar-less machine, only the clamping unit 12th is shown. This tie-bar-less machine has only one - relatively large - pressure pad 3rd intended. This pressure pad 3rd is in the front plate in this case 15 integrated. The faceplate 15 is at the machine bed 13 attached. The pillow cylinder 30th is from the face plate 15 formed or attached to this (as already described). In the pillow cylinder 30th is the pressure pad room 31 trained, in which in turn the cushion piston 32 is movable. That pillow butt 32 stands over a transmission rod 18th with the movable platen 5 in connection. Via the transmission rod 18th (or via a separate drive) is the movable platen 5 along the machine longitudinal axis M relative to the fixed platen 14 movable. In this version, too, there is again a locking device 17th intended. The pillow piston 32 divides the pressure cushion area 31 in a closing pressure room 33 and in an opening pressure chamber 34 . The pressure pad 3rd stands above the hydraulic line system 7 with the conveyor 6 in connection. The hydraulic line system 7 and its function will be described in more detail later.

In the 3rd to 8th is schematically the drive device 1 shown when performing a molding stroke. In this case the drive device (consisting of pressure pads) functions 3rd , Hydraulic line system 7 , Conveyor 6 and electric drive 10th ) as mold height adjustment device.

Generally are in the 3rd to 8th the conveyor 6 , the hydraulic line system 7 and the pressure pad 3rd shown so that they are in the fixed platen 14 (or in the faceplate 15 ) are trained. Of course, different designs and arrangements can also be provided.

With reference to 3rd especially all components of the hydraulic line system 7 explained in more detail. Generally connects the hydraulic line system 7 the conveyor 6 with the pressure pad 3rd .

The hydraulic line system 7 has a second hydraulic line 72 on which the opening pressure space 34 of the pressure pad 3rd with the second room 65 the conveyor 6 connects. The second hydraulic line 72 has a fork 75 to the link line 73 on, the junction 75 the second hydraulic line 72 in a Funding section 72.6 and into a pressure pad section 72.3 divided. In the pressure pad section 72.3 the second hydraulic line 72 a second switching element (switchable valve) 82 is arranged. This switching element 82 can be in an open position OS and closed position SS take in.

The hydraulic line system 7 has a first hydraulic line 71 on which is the closing pressure space 33 of the pressure pad 3rd with the first room 64 the conveyor 6 connects. The first room 64 consists of the axially outer part 66 and the axially inner subspace 67 together. The first hydraulic line 71 has a fork 76 to the link line 73 on, the junction 76 the first hydraulic line 71 in a funding section 71.6 and into a pressure pad section 71.3 divided. In the pressure pad section 71.3 is a first switching element 81 arranged. The first hydraulic line 71 (in particular its funding section 71.6 ) includes a first branch line 71a which with the axially outer part 66 is connected, and a second branch line 71b which with the axially inner part 67 connected is. The first branch line 71a is through the junction 77 divided into two sections. In the first branch 71a is a sixth switching element 85 arranged. In the second branch 71b is a fifth switching element 86 arranged.

The hydraulic line system 7 has a link line 73 on which is the first hydraulic line 71 and the second hydraulic line 72 connects. The link line 73 forms together with (the conveyor section 71.6 ) of the first hydraulic line 71 and (the conveyor section 72.6 ) the connecting line of the second hydraulic line 70 . In the area of the link line 73 shows the hydraulic line system 7 a storage device 9 on. The storage device 9 is via a branch line 74 with the link line 73 connected. In the link line 73 is between the branch line 74 and the first hydraulic line 71 a third switching element 83 arranged. In the link line 73 is between the branch line 74 and the second hydraulic line 72 a fourth switching element 84 arranged.

All switching elements 81 to 86 are connected to a control device (not shown). This control device can with a (also not shown) control or regulating unit of the entire molding machine 2nd be connected in terms of signal technology or be integrated into this control or regulating unit. The switching states (above all open position) are via the control device OS and closed position SS ) of the switching elements 81 to 86 , preferably controllable depending on stored program sequences.

In the figures described below, only the components that are most important for the function described in each case are provided with a reference symbol. Otherwise, the description applies to the figures described so far.

The 3rd shows a starting position for the beginning of a molding stroke. Such a molding stroke is carried out when the molding tool 16 is changed. Because the newly assembled shaping tool 16 usually has a different mold height (measured along the machine longitudinal axis M), the starting position of the platen must also be 5 and 14 to be changed to each other. This starting position can be determined using the relative position of the pillow piston 32 to pillow cylinder 30th clarify. In 3rd is the pillow piston 32 relatively far to the right, which means it is a rather large shaping tool 16 assembled. Now if a smaller shaping tool 16 is clamped with a lower mold height, the starting position must be changed by the cushion piston 32 in the pillow cylinder 30th moved further to the left. This is illustrated by the fact that the position of the pillow piston 32 from the first starting position A1 (larger mold height) to the second starting position A2 (lower mold height).

In 4th the (first) idle stroke takes place. This will be the first switching element 81 and the second switching element 82 in their closed position SS switched. The other switching elements (valves) 83 to 86 are each in the open position OS . The two switching elements (valves) 81 and 82 in the pressure pad sections 71.3 and 71.6 form a shut-off device in this idle stroke 8th to interrupt the connection of the pressure pad 3rd with the conveyor 6 . If in this switching position of the switching elements 81 to 86 the delivery piston 63 the conveyor 6 through the electric drive 10th (to the left) is moved, so hydraulic fluid from the first room 64 in the second room 65 pumped. Because the shut-off device 8th the connection between pressure pads 3rd and conveyor 6 interrupts, there is no movement of the pressure pad (yet) 3rd and therefore the spar 4th . Due to the favorable geometric design, relatively little hydraulic fluid is injected into the storage device 9 pushed. More specifically, only that amount is put into the storage device 9 pushed over the axially inner subspace 67 is promoted (since the circular ring surfaces of the second room 65 and the axially outer subspace 66 are ideally executed the same).

According to 5 a (first) mold height adjustment stroke is then carried out. For this purpose, the first switching element and the second switching element 82 in the open position OS switched while the third Switching element 83 in the closed position SS is switched. The other switching elements 84 to 86 remain in the open position OS . As soon as in this switching position of the switching elements 81 to 86 the delivery piston 63 the conveyor 6 by the electric drive (to the right), on the one hand via the second hydraulic line 72 Hydraulic fluid from the second room 65 in the opening pressure chamber 34 promoted and on the other hand via the first hydraulic line 71 Hydraulic fluid from the closing pressure chamber 33 in the first room 64 promoted. This causes the pillow piston to move 32 in the pressure cushion room 31 to the left towards the second starting position A2. With this adjustment stroke of the conveyor 6 will also be the difference volume from the storage device 9 in the opening pressure chamber 34 postponed.

Depending on how far the spar 4th This process (idle stroke & adjustment stroke) must be repeated due to the changed mold height.

Accordingly, in 6 another (second) idle stroke is shown. Again is like in 4th the shut-off device 8th to interrupt the connection of the pressure pad 3rd with the conveyor 6 activated. The first room 64 with the second pressure room 65 connecting connecting line 70 for conveying hydraulic fluid between the rooms 64 and 65 is at through the shut-off device 8th broken connection of the pressure pad 3rd with the conveyor 6 open.

In 7 Another (second) adjustment stroke is shown. As in 6 are - for performing a mold height adjustment stroke of the cushion piston 32 of the pressure pad 3rd - The first switching element 81 and the second switching element 82 in the open position OS and the third switching element 83 in the closed position SS so that additional hydraulic fluid from the conveyor 6 in the opening pressure space 34 is promoted.

In 8th the second starting position A2 is then reached. The clamping unit 12th (and especially its drive device 1 ) is thus to the shape height of the newly installed shaping tool 16 customized.

With the drive device described 1 However, not only can a mold height adjustment (carried out comparatively rarely) be carried out, but the clamping force can also be applied. This is explained in more detail below. For the sake of simplicity, they are the shut-off device 8th forming switching elements 81 and 82 not shown (they are always in an open position OS ).

In 9 illustrates how the position tolerance is compensated for when closing. (With a positive connection between the spar 4th and locking device 17th (Spar nut) 17th the position tolerance of the groove geometry is compensated.) The third switching element 83 is in the closed position SS while the other switching elements 84 , 85 and 86 in the open position OS are located. The shut-off device 8th forming switching elements 81 and 82 are not shown. If the delivery piston 63 the conveyor 6 is shifted to the left, so the pillow piston 32 shifted to the right so that the flanks of the groove geometry of the spar 4th on those of the locking device 17th lie on. With this stroke we have a relatively large volume (adjustment of the spar 4th at z. B. 2 mm) with relatively small forces to be overcome (frictional force between movable platen 5 and machine bed 13 ; Inertial force at a pressure of the hydraulic fluid at 20 to 40 bar; Frictional force between movable platen 5 and spar 4th ; Frictional force between the cushion cylinder 30th and pillow piston 32 ;) needed.

In 10th the switching position is shown when the closing force is built up. The sixth switching element 86 in the first branch 71a of the funding section 71.6 the first hydraulic line 71 is in the closed position SS . The other switching elements 83 to 85 are in the open position OS . Through this switching position when the delivery piston is displaced 63 only the small cylinder surface of the conveyor rod is to the left 68 in the axially inner part 67 used so that on the delivery piston 63 a lower force acts than if the entire piston surface is used. Will the delivery piston 63 Moved to the left, in this switch position the cushion piston is compressed by the hydraulic fluid to approx. 300 bar 32 and with it the spar 4th moved further to the right, thus building the closing force. With this "hub" - the spar 4th does not move anymore, it expands due to the pressurization - becomes a relatively small volume (compression of the hydraulic fluid from approx. 20 bar to approx. 300 bar) with relatively large forces (approx. 7 to 15 times as large as when balancing the Position tolerance) is required.

As soon as the closing force is built up, the switching elements are also 83 to 85 in the closed position SS switched. This causes the pressure in the closing pressure chamber 33 (and in the first hydraulic line 7 down to the switching elements 85 and 86 ) locked so that the load on the conveyor 6 (Delivery piston 63 , Drive rod 69 and electric drive 10th ) is as low as possible (see 11 ).

In 12th it is shown that compression takes place before the actual closing force is reduced. For this, the switching elements 83 to 85 back to the open position OS switched. At the same time, the delivery piston 63 moved to the left (in the direction of the clamping force build-up).

Then takes place according to 13 the clamping force build-up. The switching elements remain 83 to 86 in the same position as in 12th . The delivery piston 63 the conveyor 6 but is moved to the right (in the direction of closing force reduction), so that hydraulic fluid enters the opening pressure chamber 34 and on the other hand hydraulic fluid from the closing pressure chamber 33 is promoted.

In 14 the spar is reset 4th . For this there is the third switching element 83 in the closed position SS . The other switching elements 84 to 86 are in the open position OS . By moving the delivery piston 63 to the right, the pillow piston 32 moved to the left.

In 15 the initial position (A1 or A2, depending on the mold height) is reached again.

In 16 shows how an increased opening force is applied and, if necessary, tearing open with the pressure pads 3rd can be carried out. (This can also be done with an additional rapid lifting device with lower forces.) Only the fourth switching element is used for this 84 in the closed position SS switched. The other switching elements 83 , 85 and 86 are in the open position OS . For supportive opening (displacement of the pillow piston 32 to the left) takes place in the opening pressure chamber 34 an additional pressurization when the delivery piston 63 (to the right) in the direction of closing force reduction. With this stroke, a relatively small volume (compression of the hydraulic fluid to 20 to 40 bar) with relatively low forces (compression of the hydraulic fluid to 20 to 40 bar) is used, so that an increased opening force (for example of approximately 260 kN, depending on the size) is achieved. By the switching position of the switching elements 83 to 86 is at the displacement of the delivery piston 63 to the right is the annular surface of the delivery piston in the axially outer part 66 used as an effective piston surface.

In 17th is the conveyor 6 trained as a single-stage power converter. That is, the first pressure room 64 is designed as a one-piece chamber (ring-shaped in cross section). With this first pressure room 64 there is only one line in the form of the first hydraulic line 71 in connection. The shut-off device 8th is here by the first switching element 81 in the pressure pad section 71.3 the first hydraulic line 71 and by the second switching element 82 in the pressure pad section 72.3 the second hydraulic line 72 educated. In the link line 73 are the third switching element 83 and the fourth switching element 84 arranged. The storage device 9 is with the link line 73 connected. The link line 73 forms together with the conveyor section 71.6 the first hydraulic line 71 and the conveyor section 72.6 the second hydraulic line 72 the connecting line 70 . The basic functions of this conveyor 6 in the form of a single-stage power booster are the same as for the two-stage power booster, which is why reference can be made to the above statements. The differences are that due to the one-stage structure of the conveyor 6 a comparatively long stroke and subsequently a large installation space is required or alternatively a high force on the conveyor 6 or the electric drive 10th works.

18th shows in a cross section an embodiment in which the conveyor 6 into the pressure pad 3rd is integrated. Are concrete in the pillow piston 32 Cavities formed, for example the delivery piston 63 the conveyor 6 in the pillow piston 32 is movably mounted. Even the switching elements 81 to 84 and the associated lines of the hydraulic line system 7 are in the pillow piston 32 educated. The conveyor 6 is in 18th - similar to in 17th - trained as a single-stage power converter.

In contrast, in 19th an embodiment shown in the conveyor 6 also in the pillow piston 32 is designed or arranged, the conveyor 6 but is designed as a two-stage pressure intensifier.

All reference numerals in the 18th and 19th refer to the same components as in the other figures and exemplary embodiments. The functions of the individual components of this drive device 1 according to 18th or according to 19th are analogous to the previously described variants.

Reference list

1

Drive device

2nd

Molding machine

3rd

Pressure pad

30th

Pillow cylinder

31

Pressure cushion room

32

Pillow butt

33

Closing pressure chamber

34

Opening pressure chamber

4th

Spar

5

movable platen

6

Conveyor

61

Conveyor cylinder

62

Funding area

63

Delivery piston

64

first room

65

second room

66

axially external subspace

67

axially internal part space

68

Conveyor bar

69

Drive rod

7

Hydraulic line system

70

Connecting line

71

first hydraulic line

71.3

Pressure pad section

71.6

Funding section

71a

first branch line

71b

second branch line

72

second hydraulic line

72.3

Pressure pad section

72.6

Funding section

73

Link line

74

Branch line

75

Junction

76

Junction

77

Junction

8th

Shut-off device

81

first switching element

82

second switching element

83

third switching element

84

fourth switching element

85

fifth switching element

86

sixth switching element

9

Storage device

10th

Electric drive

11

Injection unit

12th

Clamping unit

13

Machine bed

14

fixed platen

15

Faceplate

16

Shaping tool

16a

Mold half

16b

Mold half

17th

Locking device

17a

Half shell

17b

Half shell

18th

Transmission rod

SS

Closed position

OS

Open position

M

Machine longitudinal axis

A1

first starting position

A2

second starting position

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102016006108 A1 [0004]
• EP 1388404 [0005]
• EP 1331079 B1 [0006]
• EP 2242633 B1 [0007]
• EP 1321272 B1 [0009]
• DE 102015011425 A1 [0010]

Claims (19)

Drive device (1) for a shaping machine (2), in particular for an injection molding machine, with - at least one hydraulically driven pressure cushion (3), via which a spar (4) or a movable platen (5) of the shaping machine (2) for applying the clamping force can be moved , - A conveying device (6) for conveying a hydraulic fluid, the conveying device (6) comprising a conveying cylinder (61), a conveying chamber (62) formed in the conveying cylinder (61) and filled with hydraulic fluid, and a conveying piston (63) movable in the conveying chamber (62) ), the delivery piston (63) dividing the delivery space (62) into a first space (64) and a second space (65), and - a hydraulic line system (7) filled with hydraulic fluid, via which the delivery device (6) is also included the pressure pad (3) is connected, characterized by - a shut-off device (8) for interrupting the connection of the pressure pad (3) to the conveying device (6) and - a d A connecting line (70) connecting the first space (64) to the second space (65) for conveying hydraulic fluid between the spaces (64, 65) when the pressure pad (3) is interrupted by the shut-off device (8) to the conveying device (6) . Drive device after Claim 1 , characterized in that the pressure cushion (3) has a cushion cylinder (30), a pressure cushion chamber (31) formed in the cushion cylinder (30) and filled with hydraulic fluid and a cushion piston (32) movable in the pressure cushion chamber (31), the cushion piston (32 ) divides the pressure cushion chamber (31) into a closing pressure chamber (33) and an opening pressure chamber (34). Drive device after Claim 2 , characterized in that the hydraulic line system (7) - a first hydraulic line (71), which connects the closing pressure chamber (33) of the pressure cushion (3) to the first chamber (64) of the conveying device (6), - a second hydraulic line (72) which connects the opening pressure chamber (34) of the pressure cushion (3) to the second chamber (65) of the conveying device (6), and - a connecting line (73) which connects the first hydraulic line (71) and the second hydraulic line (72), having. Drive device after Claim 3 , characterized in that in the first hydraulic line (71) between a branch (76) to the connecting line (73) and the closing pressure chamber (33) a first switching element (81), preferably for performing a conveyor device empty stroke, is arranged and / or that in the second hydraulic line (72) between a branch (75) to the connecting line (73) and the opening pressure chamber (34) a second switching element (82), preferably for performing a conveyor device empty stroke, is arranged. Drive device after Claim 4 , characterized in that the first switching element (81) and the second switching element (82) can be brought into a closed position (SS) in order to carry out a conveying device empty stroke of the conveying piston (63) of the conveying device (6), the first switching element (81) and the second switching element (82) together form the shut-off device (8). Drive device according to one of the Claims 1 to 5 , characterized in that a third switching element (83) is arranged in the connecting line (73). Drive device after Claim 6 , characterized in that the first switching element (81) and the second switching element (82) can be brought into an open position (OS) and the third switching element (83) in order to carry out a mold height adjustment stroke of the cushion piston (32) of the pressure cushion (3) a closed position (SS) can be brought. Drive device according to one of the Claims 1 to 7 , characterized in that the pressure cushion chamber (31), the delivery chamber (62) and the hydraulic line system (7) form a closed hydraulic circuit. Drive device according to one of the Claims 1 to 8th , characterized in that the hydraulic line system (7), preferably in the region of the connecting line (73), is connected to a storage device (9), preferably a bladder accumulator. Drive device after Claim 9 characterized in that the storage device (9) is connected to the connecting line (73) via a branch line (74) branching off from the connecting line (73), wherein in the connecting line (73) between the branch line (74) and the first hydraulic line ( 71) the third switching element (83) is arranged and a fourth switching element (84) is arranged in the connecting line (73) between the branch line (74) and the second hydraulic line (72). Drive device according to one of the Claims 1 to 10th , characterized in that the conveyor device (6) as a two-stage force converter is formed, preferably in that the second space (64) is formed in two parts - with an axially outer partial space (66) with a cross-section and with a separate, inner axial partial space (67). Drive device after Claim 11 , characterized in that the first hydraulic line (71) has a first branch line (71a) and a second branch line (71b), the first branch line (71a) with the axially outer, annular partial space (66) and the second branch line (71b) is connected to the axially inner part space (67). Drive device after Claim 12 , characterized in that a fifth switching element (85) is arranged in the second branch line (71b) and a sixth switching element (86) is arranged in the first branch line (71a). Drive device according to one of the Claims 1 to 13 , characterized in that the conveyor device (6) can be driven by an electric drive (10). Drive device after Claim 14 , characterized in that the delivery piston (63) can be moved by the electric drive (10) relative to the delivery cylinder (61), preferably linearly. Molding machine (2), in particular injection molding machine, with a drive device (1) according to at least one of the preceding claims. Molding machine after Claim 16 , with an injection unit (11) and a clamping unit (12), the clamping unit (12) comprising a machine bed (13), a fixed platen (14) connected to the machine bed (13) and the platen (13) movable on the machine bed (13) 5), the movable platen (5) being drivable by the drive device (1). Molding machine after Claim 17 , characterized in that the clamping unit (12) has four spars (4) passing through the mold mounting plates (5, 14), each spar (4) being connected to a cushion piston (32) of a pressure cushion (3) of the drive device (1) is. Molding machine after Claim 17 characterized in that the clamping unit (12) is designed without a tie bar, the cushion piston (32) being connected to the movable platen (5) and the cushion cylinder (30) being connected to an end plate (15) of the clamping unit (15) attached to the machine bed (13). 12) is connected or is formed in this end plate (15).

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