EP3243645B1 - Forming device and method for controlling a forming device - Google Patents

Description

The invention relates to a forming device with a plunger for machining workpieces, comprising a main drive unit connected to the plunger and an intermediate drive for moving the plunger. The invention further relates to a method for controlling a corresponding shaping device.

Devices for forming, separating and joining workpieces, for example sheet metal or forgings, are known. For example, eccentric presses or toggle presses are used for this.

In such forming devices, servomotors are used as the drive motor in the drive unit for positioning the ram in a predetermined position along its movement path.

From the DE 102005001878 B3 a servo press with toggle lever gear is also known which, in addition to a position-controlled main drive, also has a position-controlled intermediate drive which drives the tappet to increase the tappet stroke in an upper range of motion in which the toggle lever arms form an acute angle and from which they do not move on their own can. Due to the fact that the demands on the workpieces to be processed continue to increase, there is a high need for forming devices which enable a particularly high forming quality and additional work steps on the workpiece to be formed in the closing and opening movement of the ram. For this it is necessary that the guidance of the press ram and the power transmission of the drive unit to the press ram are further improved.

An additional drive unit to a main drive in a press is also in the document US 2013/0247781 A1 disclosed. However, this additional drive unit is not intended to move the plunger along the movement path of the main drive, but only to compensate for a tilting movement of the plunger.

Another important aspect of modern forming device is its increase in efficiency, both the operating costs and the unit costs for those on the forming device lower workpieces to be manufactured.

The invention is therefore based on the object of providing a reshaping device with which a high reshaping quality of a workpiece and additional work steps on the workpiece to be reshaped are made possible particularly efficiently in the closing and opening movement of the ram. The invention is also based on the object of providing a control method for a corresponding shaping device.

The invention achieves the object by means of a shaping device with the features of claim 1 and a method with the features of claim 12. Advantageous developments of the invention are specified in the dependent claims. All of the features described, either individually or in any combination, are fundamentally the subject of the invention, regardless of how they are summarized in the claims or their relationship.

The inventive forming device has a plunger which can be moved back and forth in at least one predetermined direction and a main drive unit for driving the plunger, which has a clutchable, non-position-controlled drive motor with a flywheel, a drive shaft with an eccentric guide unit and a gearbox with the eccentric guide unit and the tappet and a position-controlled intermediate drive, which is connected to the tappet, comprises a separate intermediate drive shaft and is designed to generate a positioning movement of the tappet.

The intermediate drive thus provides a drive system connected in parallel to the main drive, which has a low drive torque in relation to the main drive and enables exact positioning of the tappet in a predetermined position with particularly low energy consumption. In addition, the decoupling of the drives on two separate drive systems and in particular two independently driven separate drive shafts ensures particularly high operational reliability.

The two drives, namely the main drive unit and the position-controlled intermediate drive, are only connected to each other via the plunger and not via a direct connection in terms of gear technology. That is, apart from the coupling via the plunger, the main drive unit and the position-controlled intermediate drive are mechanically separate from one another. The two drives can be operated synchronously during operation. The main drive unit and the intermediate drive are synchronized, for example, by means of an electronic control. This can comprise a controller unit, with which in particular the position-controlled intermediate drive can be controlled. The main drive unit can act as a "master" and the position-controlled intermediate drive as a "slave". This construction and control ensures, for example, protection against mechanical damage when the press is started up and in the event of defects in the drive.

In addition to devices for shaping, a forming device is also understood to mean devices with rams for separating and joining workpieces, in particular sheet metal or forgings. Accordingly, the work performed on the workpiece can be understood to mean forming, cutting or joining. This means that the term forming is understood to mean not only changing the shape of a workpiece, but also the cutting of a workpiece or the joining of workpieces. Forming devices according to the invention are preferably mechanical presses.

The shaping device has at least one plunger, but can optionally also comprise a plurality of plungers for machining workpieces. Only individual plungers or all plungers can each be coupled to the main drive and / or the intermediate drive.

For the purposes of the invention, the term “ram” is also understood to mean rams with a corresponding tool for machining a workpiece.

As already mentioned, position-controlled drive units have the particular advantage that they enable precise movement control of the plunger in comparison to the so-called overtravel of the plunger, which occurs in drive units that are not position-controlled. A position-controlled drive unit thus makes it possible to stop (position) the plunger in a predetermined exact position along its movement path and, if necessary, to hold it in this position. Because due to the necessary Press force for reshaping a workpiece position-controlled drive units of mechanical presses must be designed accordingly large and have a high energy requirement, the economical operation of mechanical presses with such main drive units is difficult.

Drive units that are not position-controlled, for example conventional frequency-controlled electric motors with a flywheel mass, on the other hand, are significantly more energy-efficient since the kinetic energy is kinetically stored in the flywheel mass. Drive units that are not position-controlled, however, do not allow the plunger to stop in a predetermined, exact position, since, as mentioned above, they have a caster path.

The position-controlled intermediate drive can in particular comprise one or more servomotors, asynchronous motors, synchronous motors, direct current motors or torque motors.

The positioning movement of the plunger is understood to mean a movement of the plunger generated by the intermediate drive along a section of its movement path, possibly with the plunger stopping in a predetermined exact position. The movement path of the plunger is understood to be the movement path of the plunger that can be operated by the main drive. The intermediate drive is not designed to enlarge the movement path, for example the tappet stroke, but in particular for particularly precise positioning of the tappet along the movement path made possible by the main drive.

The positioning movement can take place along an opening movement and / or a closing movement of the plunger. The positioning movement of the plunger can also take place along a working movement, in which case a working force applied to the plunger is generated exclusively by the intermediate drive.

The working movement of the plunger is understood to mean the movement section along its movement path in which the plunger (possibly with its tool) acts on a workpiece to be processed.

The opening movement is the movement section along its movement path, in which the plunger is guided away from the workpiece, for example raised after the working movement, while the closing movement is the movement section of the plunger with which the plunger is guided, for example, lowered to the workpiece.

In an open position (along the movement path of the opening movement and / or the closing movement), the forming device can be loaded with a new workpiece or, for example, further work processes can be carried out on the workpiece present in the forming device.

The predetermined direction of movement can be a vertical direction in the generic shaping device, so that the plunger is moved vertically up and down.

The main drive unit has at least one drive motor with a flywheel, which act on a drive shaft. Alternatively, however, the main drive can also comprise several identical or similar drive shafts with one or more identical or identical drives with a flywheel.

The drive motor can be, for example, a conventional electric motor with a corresponding known flywheel, for example a flywheel. Between the drive motor with a flywheel is also a largely known clutch for engaging and disengaging the drive motor with a flywheel, and a likewise largely known brake for braking the main drive, preferably by means of friction.

The drive motor and / or the flywheel are connected to the drive shaft via a clutch in order to drive it. Couplable is understood to mean the establishment of a force-transmitting connection between the drive shaft and the drive motor with a flywheel. This makes it possible to couple or decouple the drive motor with the flywheel from the drive shaft and / or to decouple it during certain movements of the plunger, for example during a work movement that requires a high workforce, and / or during the opening movement without exact positioning of the plunger to brake in order to transmit the power of the main drive unit and the flywheel via the gearbox to the tappet. The flywheel with drive motor remains preferably engaged when the plunger opens in order to be able to overcome its own extended position with the main drive. If no positioning movement is necessary after the working movement, the flywheel with the drive motor is only disengaged shortly after the ram's top dead center.

In the uncoupled state, the kinetic energy is kinetically stored in the flywheel and the drive shaft rotates at the nominal speed or loads the flywheel. While the drive motor with flywheel mass is separated from the drive shaft, the movement of the tappet is generated via the additional drive. However, since this only has to move the mass of the plunger and works against the resistance of the toggle lever mechanism and the eccentric guide, the force of the intermediate drive to be applied to move the plunger is significantly lower.

The design of this two-part drive for a forming device with a main drive unit and an intermediate drive is particularly suitable for presses with a pressing force from 400 t. The stroke height that can be traversed by the ram is specified by the main drive unit and the gearbox.

The transmission is provided between the eccentric guide unit and the tappet for transmitting the force generated by the drive motor of the drive unit.

The transmission can preferably be designed as a connecting rod, which comprises the eccentric guide unit and is coupled to the tappet, for example via a pressure point.

The transmission is particularly preferably designed as a toggle lever transmission with at least two toggle lever transmission arms. This connecting device between the toggle lever arms and the eccentric guide unit preferably has in each case a push rod which is connected with a first end to the eccentric guide unit and with a second end opposite the first end to an upper lever arm of a toggle lever arm.

Furthermore, the push rod can be mounted, for example, in a guide on the press frame (stand guide) and / or a link guide in the upper lever arm of the toggle lever arm. Here, the push rods can preferably be with a single eccentric Be connected to the guide unit, which is arranged on a (possibly individual) drive shaft. This is in turn driven by one or more flywheel drive motors.

The toggle lever mechanism preferably has at least two toggle lever arms which are connected with a lower end to the tappet and with an upper end to the push rod. As already indicated above, each toggle lever arm can have two lever arms, for example an upper and a lower lever arm. One or both lever arms can be cranked. In addition, each toggle lever arm can be rotatably mounted on a central bearing axis. The central bearing axis is connected to the press frame, for example, and can engage in the upper lever arm. The toggle arms are preferably arranged in mirror image around a vertical central axis intersecting the drive shaft.

In this embodiment, the eccentric guide unit on the drive shaft can be understood to mean connecting elements which are each connected to a toggle lever arm via a push rod and are eccentric, i.e. are arranged off-center on the drive shaft.

This design of the eccentric guide unit and the toggle lever arms enables the use of a particularly preferred embodiment of the press with a single driven drive shaft and a single eccentric guide unit which is connected to both toggle lever arms and the drive shaft in a particularly favorable manner. This embodiment ensures in a particularly simple manner a synchronous toggle lever arm movement and thus also the precise movement of the ram.

The main drive unit with an eccentric guide unit, toggle kinematics and tappet connection is thus in particular in accordance with DE 2014 111 683.6 trained only without position-controlled drive motor in the main drive unit.

According to a development of the invention, the intermediate drive is arranged between the drive unit and the tappet and between the toggle arms of the toggle mechanism. For example, the additional drive can be in the vertical direction below the drive unit and above the tappet and - in most cases in the vertical direction extending toggle arms - be arranged in the horizontal direction between the toggle arms. The intermediate drive is positioned, for example, in the area of a vertical central axis of the press. This advantageous arrangement of the intermediate drive enables a particularly compact construction of the press.

The intermediate drive particularly preferably has a position-controlled drive motor connected to the intermediate drive shaft and an eccentric guide unit which is connected to the tappet via an intermediate drive gear, in particular an intermediate toggle lever gear or an intermediate drive connecting rod.

The intermediate drive shaft is preferably not uncoupled from the position-controlled drive motor. That is, in contrast to the main drive unit, the intermediate drive is permanently connected to the intermediate drive shaft. The intermediate drive is thus also designed without a flywheel.

The additional drive is designed to drive or brake the plunger alone, to follow the movement of the plunger without applying any force to the plunger and / or to apply a force to the plunger in addition to the main drive, ie the available moment of the intermediate drive can supplement the resulting press force of the main drive.

An intermediate drive shaft is understood to mean a drive shaft driven by a drive motor of the intermediate drive, which is formed separately from the drive shaft of the main drive unit.

The intermediate drive shaft is thus structurally separate from the drive shaft of the main drive and can in particular be arranged parallel to the drive shaft of the main drive.

The intermediate toggle mechanism or the intermediate drive connecting rod can be designed in accordance with the toggle lever mechanism or connecting rod of the main drive unit described above. The transmission of the main drive is preferably designed as a toggle lever transmission and the transmission of the intermediate drive as a connecting rod.

The intermediate drive shaft can be mounted on a bearing unit. However, the intermediate drive particularly preferably has two bearing units for supporting the intermediate drive shaft, as a result of which the precision of the ram movement during the closing and position movement is further improved. Each storage unit can, for example, be connected to a frame of the forming device.

In order to be able to safely transmit the high forces of the main drive unit, at least the bearings of the main drive unit, the eccentric guide unit and the toggle lever mechanism are designed as slide bearings. Accordingly, the few bearings of the intermediate drive can at least partially be designed as plain bearings.

However, in order to further improve the positioning accuracy of the tappet, it is provided according to a development of the invention that the bearings of the intermediate drive, in particular the intermediate drive shaft and / or an intermediate gear, are roller-supported. The roller bearings can be designed to be free of play or at least largely free of play, so that, in contrast to the plain bearings, they enable the plunger to move as far as possible without play. The plunger can thus be positioned particularly precisely during the positioning movement. The roller bearings are designed in particular as cylindrical roller bearings, since this design is characterized by a high load rating and the typical permissible speeds are far from being exhausted. Cylindrical roller bearings with a tapered bore can also be adjusted without play. Alternatively, the roller bearings can also be designed, for example, as angular contact ball bearings, which are particularly easy to adjust without play with a lower load rating.

As already mentioned above, the intermediate drive preferably follows the movement of the tappet. The bearing unit is particularly preferably resiliently mounted so that forces acting on the intermediate drive and coming from the main drive unit do not damage the intermediate drive. The resilient mounting can be designed as a hydraulic mounting, for example comprising a (prestressed) hydraulic cushion.

The hydraulic cushion can also be designed as a shock absorption, which releases hydraulic fluid at a force that is determined beforehand in terms of its strength. In the case of cut impact damping, for example, hydraulic fluid flows from the prestressed hydraulic cushion into a collecting container in order to dampen the impinging force.

As soon as the shock absorption is relieved, the discharged liquid is immediately and fully automatically returned to the hydraulic cushion and a pre-tension is generated in the hydraulic cushion again.

In addition or in addition, the connecting rod is particularly preferably resiliently mounted in the tappet. A preloaded hydraulic cushion can also be provided for this, corresponding to the mounting of the bearing unit. This resilient mounting between the connecting rod and the tappet is also particularly preferably designed as an overload protection.

The resilient bearings of the bearing unit and the connecting rod in the tappet thus jointly form a system of springs connected in parallel, the stiffness of which is matched to one another in such a way that the stiffness of the auxiliary drive is less than the stiffness of the drive unit connected in the forming process.

Plain bearings are subject to play due to their design. In order to minimize play in the movement of the slide bearings, it is known to use a ram weight compensation. Tappet weight compensation is a device that counteracts the weight of the tappet (and the upper tool). Without weight compensation, gravity shifts the center point in the slide bearings of the drive unit, i.e. the shafts lie in the direction of gravity, i.e. against the process force, in the slide bearings.

With the build-up of force that counteracts gravity, the shaft in the plain bearing moves to the opposite contact surface. The stroke in the plain bearing is almost as large as the bearing play and leads to knocks in the bearing. The aim of this weight compensation is to prevent these impacts by pulling the plunger including the tool and the effective drive components upwards in the forceless closing movement. Large pneumatic cylinders are known as a solution for this.

In order to minimize the bearing play in the slide bearings, in particular of the main drive, a tensioning device for tensioning the intermediate drive against the main drive unit is arranged according to a development of the invention. The tensioning device can be arranged alternatively or in addition to the ram weight compensation.

The tensioning device moves the intermediate drive or at least the intermediate drive shaft against the main drive unit or at least against the drive shaft of the main drive unit.

Since the bearing of the intermediate drive shaft is preferably free of play or largely free of play via roller bearings and is designed as a separate shaft, this, for example vertical displacement of the entire intermediate drive shaft against the structure of the press and thus also against a play-bearing main drive unit, can have the shafts in the plain bearings are pressed against the contact surface of the plain bearings in the direction of the process force. This reliably prevents a stroke (due to play) in the plain bearings when the force is built up.

The tensioning device can be designed, for example, as a wedge system. The wedge system can be arranged in particular on the bearing units of the intermediate drive shaft and is designed such that the bearing units are displaced with the intermediate drive shaft against the main drive unit.

The intermediate drive can - as stated - be carried out with an eccentric guide unit and a toggle mechanism or a connecting rod. Alternatively, the intermediate drive can be used as a screw jack drive, in which the motor unit (s) with the separate intermediate drive shaft effects the movement of the tappet, or as a servohydraulic drive, in which the motor unit (s) with the separate intermediate drive shaft, one or more hydraulic cylinders designed as gearboxes Cause movement of the plunger, be formed.

The particular advantage of the screw jack drive is the good accessibility due to an arrangement on the outside of the ram, a reduction in a possible angular error due to the longer guide length, the installation of standardized components and the variable stroke in contrast to an eccentric without stroke adjustment.

The advantages of the servo-hydraulic drive largely correspond to those of the screw jack drive. In addition, the hydraulics have a high energy density and thus take up little space.

Furthermore, the object on which the invention is based is achieved by a method having the features of claim 12.

According to the inventive method for controlling a forming device according to at least one of claims 1 to 11, in a forming device whose main drive unit and intermediate drive are mechanically coupled only via the tappet, the main drive unit and the intermediate drive are synchronized, the intermediate drive at least the target curve of the main drive unit section by section.

The synchronization provides that the intermediate drive after engaging the main drive unit, i.e. of the drive motor of the main drive unit, follows the target curve of the main drive unit. Here, the target curve for the intermediate drive, in particular the jerk when the main drive unit is engaged, is recorded when the press is retracted, for example using measurement technology from the isolated movement of the main drive unit.

The target curve is understood to mean the movement of the ram path over time (hereinafter also the path-time curve). The target curve is understood to mean in particular a path-time curve measured from the actual curve of the main drive unit. The synchronized position-controlled intermediate drive thus optimally travels the same distance-time curve with the tappet as the main drive unit, and simultaneously with the main drive unit. The intermediate drive actively transfers a force to the ram and is not only dragged along by the main drive.

The synchronization thus takes place, for example, in such a way that after the main drive unit is engaged, the intermediate drive follows the setpoint curve of the main drive unit according to the master-slave principle, the main drive unit acting in particular as the “master” and the position-controlled intermediate drive as the “slave”. That is, the main drive unit (master) specifies a path-time curve, the position-controlled intermediate drive (slave) travels at least in sections with the same path-time curve at the same time.

Passing through in sections means that the setpoint curve specified by the main drive unit is traversed by the intermediate drive, at least in the periods in which the main drive unit also applies a force to the tappet.

The main drive and the intermediate drive are particularly preferably synchronized by means of a controller unit which, for example, carries out electronic control of the position-controlled drive motor of the intermediate drive. For example, the intermediate drive can be controlled accordingly via a rotary encoder of a servomotor of the intermediate drive.

The setpoint curve of the main drive is also particularly preferably recorded, the synchronization of the two drives being carried out on the basis of the recorded setpoint curve. The setpoint curve of the main drive can be recorded in a particularly advantageous manner by means of a measuring device which is coupled, for example, to the controller unit.

For the recording, the plunger is detected, for example, from a position outside of top dead center by engaging the main drive. The target curve arises from the superimposition of the kinematics of the uninterrupted run and the recording.

The setpoint curve thus created, in particular the jerk when engaging, is then followed by the intermediate drive in order to achieve a synchronous drive, since dragging the driveless intermediate drive, particularly in the top and bottom dead center, can lead to undesired sticking of the drive.

The setpoint curve can also be saved, for example, in the controller unit and recorded again as often as required, e.g. to Wear in the clutch and brake must be taken into account.

Of course, it is also possible to drive the intermediate drive without the main drive unit, in which case the intermediate drive can likewise follow the (present) target curve of the main drive unit, but advantageously a separate one For example, traverses the specified path-time curve. This can be done without the clutch jerk of the main drive. The main drive unit can also be used to drive the plunger without the intermediate drive. In order to avoid the undesired sticking of the intermediate drive, the hydraulic cushions on the intermediate drive can be emptied, for example, so that the intermediate drive has sufficient play for free running. In this respect, the forming device and the control method offer particularly high flexibility when using the press and, at the same time, the possibility of correspondingly minimizing the energy consumption of the press or adapting it to the press situation.

Although some aspects have been described in connection with a device, it goes without saying that these aspects also represent a description of the corresponding method, so that a block or a component of a device can also be understood as a corresponding method step or as a feature of a method step . Analogously, aspects that have been described in connection with or as a method step also represent a description of a corresponding block or detail or feature of a corresponding device. Some or all of the method steps can be carried out by a hardware apparatus (or using a hardware apparatus). such as B. a microprocessor, a programmable computer or an electronic circuit. In some embodiments, some or more of the most important process steps can be performed by such an apparatus.

Fig. 1

schematisch in einer Ansicht eine Kniehebelpresse mit einem Zusatzantrieb und einem Stößel;

Fig. 2

schematisch in einer perspektivischen Darstellung eine Zwischenwellenlagerung des Zusatzantriebs aus Fig.1;

Fig. 3

schematisch im Querschnitt die Zwischenwellenlagerung aus Fig. 2;

The invention is described in more detail below with the aid of several exemplary embodiments. It shows:

Fig. 1

schematically in a view a toggle press with an additional drive and a plunger;

Fig. 2

schematically in a perspective view of an intermediate shaft bearing of the auxiliary drive Fig. 1 ;

Fig. 3

schematically in cross section from the intermediate shaft bearing Fig. 2 ;

Figure 1 shows a forming device designed as a mechanical press 1 with a press frame 2 and a main drive unit 3. The main drive unit 3 has a drive motor with a flywheel (not shown here) and a central drive shaft 4, which is connected to a single eccentric guide unit 5 is. A clutch (not shown here) for engaging and disengaging the drive motor with a flywheel from the drive shaft 4 is arranged between the drive motor with a flywheel and the drive shaft 4.

The eccentric guide unit 5 is connected to two toggle lever arms 7, 8 of a toggle lever mechanism 6 via push rods (not shown here). For this purpose, each push rod is movably mounted with a first end in the eccentric guide unit 5 and with a second end opposite the first end via a connecting axis 12 in a sliding guide 13 which is arranged in a first lever arm 10a, 11a.

Stand guides 9 designed as sliding guides are also arranged, in each of which one of the push rods (here linear) is also movably mounted.

Each toggle lever arm 7, 8 comprises the first lever arm 10a, 10b with the slide guide 13 for the connecting axis 12 and a second lever arm 10b, 11b which is connected to the first lever arm 10a, 11a via a swivel joint 14. At an end opposite the swivel joint 14, the second lever arm 10b, 11b is movably connected to the tappet 16 via a tappet connection 15. The first lever arm 10a, 10b is also cranked and both toggle arms 7, 8 are mounted on the press frame 2 via a central bearing unit 18 which engages the first lever arm 10a, 11a.

The press 1 also has a press table 17. The ram 16 and the press table 17 can be connected to a press tool (not shown here), an upper tool (not shown here) being arranged on the ram 16 and a lower tool (not shown here) on the press table 17, for example. The workpiece to be machined (not shown here) is arranged between the upper and lower tools and machined when the ram 16 moves. The ram 16 is also mounted in a linear guide (not shown here) in the press frame 2.

The swivel joints 14 between the first and second lever arms 10a, 10b, 11a, 11b, the tappet connections 15 and the central bearing unit 18 are designed as slide bearings in order to be able to transmit the high forces of the drive unit 4 to the tappet 16.

An intermediate drive 19 is arranged in the vertical direction V (represented by an arrow) below the eccentric guide unit 5 and in the horizontal direction H (represented by an arrow) between the toggle lever arms 7, 8. The intermediate drive 19 is designed as an eccentric drive with a position-controlled drive motor. Alternatively, a worm gear screw jack with a position-controlled drive motor could also be provided as an intermediate drive 19.

Fig. 2 shows schematically in a perspective view a section of the intermediate drive 19 Fig. 1 . The intermediate drive 19 has an intermediate drive shaft 20 which is rotatably mounted on two bearing units 21. The bearing units 21 each comprise a roller bearing 21c arranged on the intermediate drive shaft 20 in order to enable play-free mounting and thus particularly precise movement control of the tappet 16. The bearing units 21 are connected to the press frame 2.

An intermediate drive gear 22 is arranged between the bearing units 21 and has a connecting rod 23 with a shaft 23a for connection to a pressure point 26. The intermediate drive gear 22 comprises a roller bearing 25 with an eccentric receiving unit 30 arranged in the roller bearing 25. The eccentric receiving unit 30 is connected to the intermediate drive shaft 20. This extends through the eccentric guide unit 30 into both bearing units 21. To drive the intermediate drive shaft 20, a position-controlled motor (not shown here), such as a servo motor, is also connected to the intermediate drive shaft 20.

The connecting rod 23 is rotatably connected to the pressure point 26 via its shaft 23a. For this purpose, a rotary bearing 24 comprising two roller bearings 29 is also formed between the shaft 23a and the pressure point 26. At the end opposite the shaft 23a, the pressure point 26 is coupled to the tappet 16.

Furthermore, a tensioning device 32 for tensioning the intermediate drive 19 against the main drive unit 3 is arranged. The tensioning device 32 is designed as a wedge system for moving the intermediate drive in the vertical direction towards the main drive unit.

Fig. 3 shows schematically in a cross section the section of the intermediate drive Fig. 2 .

The bearing units 21 with the intermediate drive shaft 20, the intermediate drive gear 22 with the connecting rod 23, the shaft 23a, the roller bearing 25, the eccentric guide unit 30 and the pressure point 26 with the tappet 16 connected to the shaft 23 via the rotary bearing 24 can be clearly seen.

The bearing units 21 are configured similarly to the intermediate drive gear 22 and have a receiving ring 21a with a shaft 21b and a roller bearing 21c designed to support the intermediate drive shaft 20. The bearing units 21 are also resiliently mounted in the vertical direction V. For this purpose, the free ends of the shafts 21b are designed as pistons 21d, which are mounted in a cylindrical receptacle 27, a hydraulic cushion 28 being provided as a spring.

In addition, the hydraulic cushion 28 is designed as a cut impact damping in order, for example, to absorb and cushion the high forces which occur when the drive unit 4 is coupled in or the high forces which occur when the plunger 16 breaks through during cutting movements. While in the case of a hydraulic overload safety device the spraying hydraulic fluid has to be pumped back in the idle state of the forming device 1, the cut impact damping 31 is designed in such a way that the hydraulic fluid escaping is automatically and immediately returned after relief.

The rotary bearing 24 is formed by way of rotary axis sections 23b which extend outward in the horizontal direction H at the lower end of the shaft 23a and on each of which the pressure point 26 is rotatably supported by a roller bearing 29.

The pressure point 26 is in turn spring-mounted in the plunger 16 in the vertical direction V and for this purpose has a piston shape 26a at its free end, which is hydraulically supported in a cylinder receptacle 16a in the plunger 16. The hydraulic mounting is also carried out via a hydraulic cushion 31, which, however, is designed as an overload safety device.

In operation, the intermediate drive 19 takes over the positioning movement of the plunger 16. That is, the intermediate drive 19 moves the plunger 16 with the upper tool into a precisely predetermined position, for example, towards the workpiece to be machined which is on the Lower tool is arranged. To form the workpiece, the drive motor with a flywheel mass is coupled to the drive shaft 4, so that the force of the drive motor with the flywheel mass is used via the eccentric guide unit 5 and the toggle lever mechanism 6 to form the workpiece.

After the workpiece has been formed, the drive motor can be uncoupled and the intermediate drive 19 lifts the ram 16 with the upper tool into an open position with a positioning movement. The workpiece can be processed in this way or it can be removed from the press.

After machining the workpiece in the open position, it can be removed from the forming device and a new workpiece can be inserted.

It is also possible, for example, after a first machining step - in the opening position produced by the intermediate drive - to place the plunger again on the workpiece, for example to punch or glue the workpiece. This second positioning movement can also be generated by the intermediate drive, provided that a high workforce is not necessary. In addition, the intermediate drive also makes it possible, for example, to place the plunger on the workpiece and to hold it in the attached position in order, for example, to produce a bond to the workpiece or a plurality of workpieces with a small amount of labor. If particularly high manpower is required for the second machining of the workpiece, the main drive can be coupled in for this.

Due to the design of the additional drive 19 as a position-controlled intermediate drive 19, the plunger 16 can be positioned particularly precisely. Furthermore, since the bearing 21 of the intermediate drive 19 and the connecting rod 26 does not have to withstand high forming loads and can therefore have roller bearings, the tappet 16 can be moved almost without play, which significantly improves the precision of the movement.

The use of a drive motor with a flywheel in the main drive unit to generate the work force for the forming movement of the ram also enables a particularly low energy consumption of the forming device, so that the forming device can be operated particularly economically. <b> List of reference symbols </b> 1 Forming device 21a Receiving ring 2nd Press frame 21b shaft 3rd Main drive unit 21c roller bearing 4th drive shaft 21d piston 5 Eccentric management unit 22 Intermediate drive gear 6 Toggle lever gear 23 Connecting rod 7, 8 Toggle arms 23a shaft 9 Stand guide 23b Axis sections 10a, 11a First lever arm 24th Pivot bearing 10b, 11b Second lever arm 25th roller bearing 12th Connecting axis 26 Pressure point 13 Sliding guide 26a Piston shape 14 Swivel 27 cylindrical mount 15 Ram connection 28 Hydraulic cushion 16 Pestle 29 roller bearing 17th Press table 30th Eccentric management unit 18th central storage unit 19th Intermediate drive 31 Hydraulic cushion 20th Intermediate drive shaft 32 Jig 21 Storage unit

Claims (14)

1. A forming device having a ram (16) which is movable back and forth in at least one predefined direction, comprising at least:

   - a main drive unit (3) for driving the ram (16), which has an engageable non-position-controlled drive motor with a flywheel mass and a drive shaft (4) with an eccentric guide unit (5),

   - a gear which is connected to the eccentric guide unit (5) and the ram (16), and

   - a position-controlled intermediate drive (19) having a separate intermediate drive shaft (20), which is connected to the ram (16) and is configured to produce a positioning movement of the ram (16), wherein a movement of the ram (16) produced by the intermediate drive (19) leads along a section of the movement path made possible by the main drive.
2. The forming device according to claim 1, characterized in that the gear of the main drive unit (3) is configured as a toggle mechanism (6) or connecting rod.
3. The forming device according to one of the preceding claims, characterized in that the intermediate drive (19) is arranged between the main drive unit (3) and the ram (16) and between two toggle levers (7, 8) of the toggle mechanism (6).
4. The forming device according to one of the preceding claims, characterized in that the intermediate drive (19) has a position-controlled drive motor connected to the intermediate drive shaft (20) and an eccentric guide unit (30) which is connected by means of an intermediate drive gear (22), in particular a toggle mechanism or a connecting rod (23), to the ram (16).
5. The forming device according to one of the preceding claims, characterized in that the intermediate drive (19) has two bearing units (21) for mounting the intermediate drive shaft (20).
6. The forming device according to one of the preceding claims, characterized in that the bearings of the intermediate drive (19), in particular of the intermediate drive shaft (20) and/or of an intermediate gear (22), are mounted on anti-friction bearings.
7. The forming device according to one of the preceding claims, characterized in that the bearing units (21) and/or the connecting rod (23) is/are mounted in a spring-like manner in the ram (16).
8. The forming device according to one of the preceding claims, characterized in that the spring-like mounting is executed as a hydraulic bearing, in particular having hydraulic cushions (28, 31).
9. The forming device according to one of the preceding claims, characterized in that an overload protection is arranged between the connecting rod (23) and the ram (16).
10. The forming device according to one of the preceding claims, characterized in that a clamping device (32) for bracing the intermediate drive (19) against the main drive unit (3) is arranged.
11. The forming device according to one of the preceding claims, characterized in that the intermediate drive (19) is configured as a position-controlled spindle stroke drive or as a servo-hydraulic drive.
12. A method for controlling a forming device (1) according to at least one of claims 1 to 11, characterized in that the main drive unit (3) and the position-controlled intermediate drive (19), which are only mechanically coupled to one another by means of the ram (16), are synchronized by means of a nominal curve of the main drive unit (3), wherein the intermediate drive (19) passes through the nominal curve of the main drive unit (3) at least in sections and the intermediate drive produces a movement of the ram, which leads along a section of the movement path made possible by the main drive.
13. The method according to claim 12, characterized in that the nominal curve of the main drive unit (3) is plotted and the synchronizing of the intermediate drive (19) is effected on the basis of the plotted nominal curve of the main drive unit (3).
14. The method according to claim 12 or 13, characterized in that the synchronization is effected with the aid of a controller unit.

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