JP5026977B2 - Molding press drive system - Google Patents

Description

  The present invention relates to a drive system for a molding press (Umformpresse), that is, a molding press provided with an eccentric body mechanism or a crank mechanism for ram movement, each of the types described in the superordinate concepts of claims 1 to 4. The present invention relates to a drive system of a forming press with a toggle lever that can be driven by a crank transmission device for movement of the drive system or ram.

BACKGROUND OF THE INVENTION A press with a mechanical drive is known from German Offenlegungsschrift 14 52 772. In this known press, the primary drive unit consisting of a motor, flywheel and clutch / brake combination, a gear transmission for output branching, and a lift transmission with a lever mechanism corresponding to each operating point, respectively. Followed by a secondary drive part with the device. In this case, the use of a lever joint drive device achieves a change in the course of movement that is sinusoidal in the crank drive device. In this known solution, in addition to the increased effort required for each of the components listed above on the primary and secondary drive parts, the stroke and speed distribution (Weg- und Geschwindigkeitsprofil) is inconveniently set.

  The disadvantage of the constant stroke distribution is that according to the solution described in the German utility model 1911865, the crank for the movement of the ram is operated alternately by the right-hand drive and the left-hand drive. Is avoided by In this case, the reciprocating motion (Pendelbewegung) with adjustable reciprocating rotational angle range (Winkelausschlag) alternately connects motor-driven fly masses (flying masses) that rotate clockwise and counterclockwise, respectively, or It is formed by an electric motor capable of reversing polarity without a fly disk. It is not expected to affect the velocity distribution during the ram stroke. Solutions using polarity-reversible electric motors require an increased peak output from the energy supply to the installation, especially at the stage of the deformation process.

  An energy store is also known from the device described in EP 0300000. The energy store releases the energy stored to accelerate the mass (mass body) or takes it out of the energy supply and stores brake energy when braking the mass or returns it to the energy supply. Based on the reciprocating rotation of the crank, a toggle lever mechanism for ram movement is operated. What is common to the two devices listed above is that the electric drive drives multiple action points via a mechanical output branch, thereby allowing each force point to correspond to each action point separately. Control is impossible.

  In the known device according to DE 10219581, a pump-driven fluid drive device commonly corresponds to each eccentric shaft or a plurality of operation points, each corresponding individually to each operation point. One eccentric shaft is driven to generate ram motion. In this case, a flexible speed / force distribution for the press ram can be adjusted. In order to minimize the peak output of the pump, it is described that a flywheel (flywheel) is alternatively used between the electric motor and the pump. Due to the fixed stroke based on the constant rotation direction of the eccentric shaft, the flexible stroke distribution of the ram is not set.

Problems and Advantages of the Invention The problem underlying the present invention is to improve the drive system used in the press so that each point of action of the ram has a freely programmable amount and sequence of strokes and a flexible speed / force distribution. To provide a drive system that can be controlled by separate force / position control. Furthermore, it is desirable that energy consumption from the supply network, cycle-based load fluctuations and power supply reactions (Netzrueckwirkung) be minimized without the use of additional energy stores. In the case of a forming press with multiple points of action, it is desirable to provide the possibility of ram tilt control.

  This object is achieved according to the invention by the features according to claim 1, claim 2, claim 3 and claim 4, i.e. forming with an eccentric body mechanism or crank mechanism for the movement of the ram. In a drive system of a press, at least one servo motor drives an eccentric body mechanism or a crank mechanism corresponding to each pressure point or each working point directly or indirectly via a transmission. The direction of the servo motor is switched between the crank angle position and the range of the extension position, or between the angle position inside the crank and the angle position outside the crank as known per se (see FIG. Claim 1) or at least one servomotor via at least one common output branch, at least two eccentric body mechanisms or clutches corresponding to the point of action. The direction of the servo motor is switched between the crank angle position and the extension position range, or, as is known per se, the crank inner angle position and the outer angle position. In a drive system of a forming press with a toggle lever driven by a crank transmission for ram movement, the at least one servomotor is directly or indirectly In addition, a toggle lever corresponding to each operating point is driven individually via a transmission device, and the direction of the servo motor is switched between the range of the bent position and the extended position of the toggle lever. Or between the inner bent position and the outer bent position of the toggle lever (Claim 3), or at least one servomotor is Is it acting on at least two toggle levers corresponding to the action point via two common output branching devices, and whether the direction of the servo motor is switched between the range of the bent position and the extended position of the toggle lever? Or by being performed between the bent position on the inner side and the outer bent position of the toggle lever (claim 4).

  Advantageous configurations of the invention are described in claims 5 to 12.

  The basic idea of the present invention is that the advantages of hydraulic presses with respect to the free programmability of stroke distribution, velocity distribution and force distribution are constrained by the stroke of increased productivity, stiffness and lower inversion point. To integrate with the advantages of mechanical presses with respect to repeatability. What is important for the invention is that one or more electric drives act as servomotors on the crank transmission, in which, in addition to the freely programmable stroke distribution, speed distribution and force distribution, the stroke And / or a flexible use of force-constrained motion sequences or motion courses. During ram movements constrained by force, the lower inversion point is controlled in relation to the programmed force, similar to a hydraulic press. In this operation mode, a single stroke of the electric drive device corresponds to a single ram stroke, and in this case, the reverse or reverse movement of the electric drive device is performed at the reversal point below the ram. The high positioning accuracy and mechanical rigidity of the servo axis also enables a stroke-constrained ram movement with a reverse movement of the electric drive at the lower inversion point of the ram. When the electric drive causes the crank drive to swing non-stop continuously at the inversion point on the lower side of the ram without stopping, in another mode of operation, the stroke of the mechanical press at high cycle speed (Taktrate) The advantages of constrained ram movement can be exploited. In this case, a double ram stroke having a forward travel and a rear travel is obtained using a stroke of the electric drive device. This reduces energy consumption and increases press cycle speed. It is possible for the electric drive to drive the crank transmission directly or indirectly via an intermediate transmission, for example a gear transmission. For large torques, it is advantageous for a plurality of servomotors to act on the crank transmission. In relation to the magnitude of the ram stroke and the length of the crank, the secondary wheel belonging to the transmission can be formed as a tooth segment. The angle of this tooth segment corresponds to the maximum possible reciprocating rotation angle region. In order to achieve a greater force, the crank transmission is combined with a toggle lever in an advantageous configuration of the invention. Furthermore, it is advantageous that the crank transmissions corresponding to the individual operating points can be controlled separately in the force / position control. Thereby, on the one hand, for the parallel holding of the rams, it is possible to compensate for tilting that can occur based on off-center force action, and on the other hand, it is possible to achieve intentional target tilting. Also important for the invention is a servo motor for the main movement of the ram and another servo motor provided in the press for the secondary movement, for example a servo for a tensioning device which can be driven by an electric motor. The energy balance of the press is improved by exchanging energy with the motor so that the energy re-stored in the generator mode of the servo motor is supplied to the servo motor in the motor mode during the braking phase in the motion cycle. It is to be done. This effect is also achieved when a plurality of presses belonging to one press line are operated with a phase shift with respect to the ram motion, and energy exchange is performed between servo motors belonging to each press for the main motion. can get.

  In the case of a conventional mechanical molding press with a fixed stroke characteristic line, the stroke / speed characteristics equivalent to the production press in the corresponding tryout press (Einarbeitungspresse) as well as the high quality requirements of prototypes such as mold matching of new tools. Need to be available. To this end, only hydraulic type tri-out presses equipped with high-speed drive devices with flexible stroke-time characteristics can be used at present. Such a tryout press requires a lot of labor when used for imitation of a production press. Since the servo motor driven drive system integrates the advantages of a mechanical press with the advantages of a hydraulic press, a nearly identical forming press is provided for tryout purposes and production.

  In the following, embodiments of the invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a separate crank drive in an internal angular position;
FIG. 2 is a schematic diagram showing a separate crank drive with combined toggle levers in an inward bending position;
FIG. 3 is a schematic diagram illustrating energy compensation between servo drives for primary and secondary motions performed via intermediate circuit coupling;
FIG. 4 is a diagram with the movement course and drive output for the main and sub-movements.

  FIG. 1 shows a part of a molding press according to the first embodiment. The molding press is driven by a driving device 2 having a crank mechanism 3. In this case, each working point of the ram 1 is driven separately. The ram 1 is shown in its upper stroke position. In the upper stroke position, the crank mechanism 3 is positioned at an inner angle position (bending position) 10 thereof. The crank mechanism 3 has a crank 8 supported by a crank bearing 18 at a head portion 19, and the crank 8 is connected to a pressure point of the ram 1 via a connecting rod 9 pivotally attached to the other end. Coupled to point of action 4. The crank 8 is driven indirectly by a freely programmable servomotor 5 with a transmission 6 located in the middle in the form of a gear transmission. Since the crank mechanism 3 for the movement of the ram 1 rotates only over a defined reciprocating rotation angle region (Winkelausschlag), the output element belonging to the transmission 6 can be formed as a tooth segment 7. The servomotor 5 allows programming of flexible, that is, free stroke and speed characteristics for the movement of the ram 1. In this case, the gear ratio of the crank mechanism 3 is taken into consideration. The position, rotation speed, and torque of the servo motor 5 are controlled by NC control so as to obtain a desired movement / force course. What is important in this case is that, in the first configuration, the course of movement is formed by an electronic cam disk that defines the target position of the ram 1 and is controlled by a virtual spindle (leitwellengesteuert.).

  In a preferred embodiment, the target torque of the servomotor 5 is corrected so that the required force is achieved at the point of action in the ram 1 in relation to the acceleration, the transmission gear ratio and other influence quantities, for example temperature and friction. However, direct force measurement or moment measurement can be dispensed with by limiting. With this drive arrangement, the forming press can on the one hand be stroke-constrained and operated with a defined lower inversion point located in the range of the extension position 13 of the crank mechanism 3. On the other hand, by restricting the force on the control unit side in the range of the extension position 13, the servo-driven molding press can be operated with a force restraint like the hydraulic press.

  Alternatively, the crank mechanism swings continuously without stopping at the lower reversal point of the ram 1, i.e. non-stop, so that the crank mechanism is stroke-constrained ram to obtain a high cycle speed. The crank mechanism can be operated to take advantage of the motion.

  At this time, the crank 8 alternately reaches the inversion point on the upper side of the ram 1 by the inner angle position 10 and the outer angle position 11. In this case, an important advantage is that the ram 1 is braked during a stage of increased energy demand due to the deformation process, compared to a mode of operation with a reversing movement of the crank mechanism 3 in the range of the extension position 13 of the crank mechanism. There is not to be. The energy consumption is reduced based on the continuous swing of the crank mechanism 3 passing through the lower reversing point non-stop. The freely programmable servo motor 5 enables flexible stroke characteristic lines. During the continuous swing of the crank 8 passing through the lower reversal point having symmetrically positioned angular positions 10, 11, the forward travel and the rear travel of the ram 1 are equal in this case. In the odd number of strokes, the motion distribution mirror program of the even number of strokes can be executed.

  Furthermore, in order to produce deformed parts, the inversion point on the lower side of the ram 1 is passed several times per pressing process, preferably by different strokes, so that the pressing per deformed part is performed. It may be advantageous for the process to be carried out several times. Based on these different strokes, the outer and inner angle positions 10, 11 are positioned asymmetrically.

  In another configuration not shown, the operating point 4 of the ram 1 can be mechanically synchronized so that the servomotor 5 acts on the crank mechanism 3 corresponding to the operating point 4 simultaneously. In this case, it is advantageous if the force transmission elements corresponding to the transmission 6, for example the tooth segments 7, are operatively connected to one another.

  In the second embodiment shown in FIG. 2, the crank transmission 14 is combined with the toggle lever 16. In this case, the crank 8 of the crank transmission 14 is driven by both servo motors 5 and the transmission 6 located in the middle, respectively, as in the first embodiment. On the output side, the crank 8 is coupled to the lever 17 of the toggle lever 16 via the pressure plate 15. The toggle lever 16 is supported on the lever bearing 20 on the frame side by a head portion 19. In this embodiment, the pressure plate 15, the lever 17, and the connecting rod 9 connected to the operating point 4 have one common pivot point, whereby the four-point toggle lever mechanism 21 is It is formed. At the inverted position on the upper side of the ram 1, the toggle lever 16 reaches the bent position 22 inside thereof. In the range of the extension position of the toggle lever 16, the lower inversion point of the ram 1 is reached. Unlike the first embodiment, it is not necessary to brake the servo motor 5 in this operation mode. This is because the crank mechanism 3 swings so as to pass through the lower inversion point non-stop during the lower inversion point of the ram.

  It is also possible for these servo drive devices 5 to act on the point of action 4 in common via the output branching section 24.

  Overall, force amplification is obtained by the combination of the crank mechanism 3 and the toggle lever 16.

  Due to the independent and independent individual position / force control of the action point 4, in both embodiments, the ram 1 can be held in parallel even in the case of an off-center force action or an eccentric force action. On the other hand, it is also conceivable that the defined target tilt of the ram 1 is adjustable during the pressing process.

  The drive device 2 using the servo motor 5 and substantially free of flywheels may cause load fluctuations having a significant peak output during energy consumption from the supply network 29. The means for improving the energy balance of the forming press will be described below with reference to FIGS.

  In addition to the servomotor 5 for the main movement of the ram 1, another servomotor 28, for example a tensioning device, is used for the secondary movement in the forming press. In the upper half of FIG. 4 there is shown a stroke-time characteristic line having a position relative to the phase for the drive of the ram 1 and the tensioning device 28. After the impact point of the ram 1 to the tensioning device, the tensioning device is actively moved by the servomotor 5 of the ram 1, in which case the associated drive 28 is tensioned for the deformation process in generator mode with braking. Apply the required force of the device. In this phase of the ram 1 having the maximum energy demand for the motor-operated servomotor 5, energy is re-stored based on the generator-operated servomotor of the tensioning device 28. Both servo motors 5 for the main motion and the servo motor for driving the tensioning device 28 are coupled to one common intermediate circuit 26 shown in FIG. Energy exchange takes place between the servomotor 5 for the movement of the ram 1 and the drive device 28 for the tensioning device.

  Another energy exchange may be performed in the press cycle shown in the diagram (FIG. 4) to achieve the upper reversal point in the servo motor braking phase for ram 1. In this case, the energy exchange is such that the energy re-stored by the ram 1 is now supplied via an intermediate circuit coupling to the driving device for the tensioning device 28 which is operated by the motor in the phase of the speed-up operation. Can be performed. The time-related course of the drive output with motor action and generator action is evident from the curves in the middle of the diagram shown in FIG. 4 for the ram 1 and the drive of the tensioning device 28, respectively. The drive power produced is shown in the lower curve. Load fluctuations can be reduced by energy exchange through intermediate circuit coupling.

  It is also conceivable to exchange energy between a plurality of molding presses. In this case, a forming press belonging to one press line is operated with a phase shift with respect to its ram motion, and energy is exchanged between each servomotor 5 for the main motion.

FIG. 6 is a schematic diagram showing a separate crank drive in an inner angle position. FIG. 6 is a schematic diagram showing a separate crank drive with combined toggle levers in an inward bending position. FIG. 6 is a schematic diagram showing energy compensation between servo drives for main and sub-movements performed via intermediate circuit coupling. FIG. 6 is a diagram having a motion course and a drive output for a main motion and a secondary motion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ram 2 Drive device 3 Crank mechanism 4 Action point 5 Servo motor 6 Transmission device 7 Tooth segment 8 Crank 9 Connecting rod 10 Angle position inside crank transmission device 11 Angle position outside crank transmission device 12 Press stand 13 Extension position Range 14 Crank transmission 15 Pressure plate 16 Toggle lever 17 Lever 18 Crank bearing 19 Head part 20 Lever bearing 21 Four-point toggle lever mechanism 22 Bending position inside toggle lever mechanism 23 Bending position outside toggle lever mechanism 24 Output branching device 26 Intermediate circuit coupling 27 Servo amplifier 28 Driving device for tensioning device 29 Supply network 30 Supply module 31 Axle regulator 32 NC control unit

Claims (13)

A drive system of a molding press for the movement of the ram (1), which is provided with an eccentric body mechanism or a crank mechanism (3) that can be controlled by a servo motor (5 ). each action point each one eccentric mechanism or a crank mechanism to respond separately to (4) (3), via a transmission (6), can be driven by at least one servomotor (5), the Servo motor (5) in force / position control during movement with direction switching between angle position (10, 11) and extension position (13) range of crank (8) and connecting rod (9) A drive system for a molding press, which can be controlled separately. A drive system of a forming press for the movement of the ram (1), in which a toggle lever (16) that can be driven by a crank transmission (14) is provided, at least one servo motor (5 ) Directly or indirectly via the transmission (6), each one of the toggle levers (16) individually corresponding to each adjacent working point (4) of the ram (1) The servomotor (5) is driven in the direction of rotation, and each of the servomotors (5) during the movement with direction switching,
The bending position of the inner or outer side of the toggle lever (16) at the corresponding angular position of the crank (8) and the connecting rod (9), and the extension position (13) of the crank (8) and the connecting rod (9). Between the range of the extended position (13) of the toggle lever (16) in the corresponding range,
-Or between the inner bent position and the outer bent position of the toggle lever (16),
In the molding press drive system, the force and position can be controlled separately. Forming press drive system for the movement of the ram (1), the at least one servomotor (5) for a plurality of crank transmissions (14), each of which is connected in common and drives one toggle lever ), The crank transmission (14) arranged parallel to the axis of each working point (4) of the ram (1) and adjacent to each other in the radial direction, The toggle lever (16) rotatably supported on the frame side is operatively coupled to each other via the transmission device (6), and the direction of the servo motor (5) is switched by the toggle lever. Between the bent position on the inner or outer side of (16) and the range of the extended position (13), or in the range of one bent position of the toggle lever (16), or itself , Molding press drive system, characterized in that takes place between the inner bending position and outside of the bent position of the toggle lever (16) as known.   When the direction of the servo motor (5) is switched between the angle position (10, 11) between the crank (8) and the connecting rod (9) and the range of the extended position (13), the stroke size and order are 2. A drive system for a forming press according to claim 1, which is freely programmable.   Between the bent position outside or inside the toggle lever (16) and the range of the extended position (13) of the toggle lever (16), or between the bent position inside and outside the toggle lever (16) 4. The drive system for a molding press according to claim 2, wherein the magnitude and order of the strokes can be freely programmed when the direction of the servo motor (5) is switched. 6. The drive system of a forming press according to claim 5, wherein both the outer and inner bent positions (22, 23) of the toggle lever (16) or the angular positions of the crank (8) are positioned symmetrically. 6. The drive system for a forming press according to claim 5, wherein both the angle positions of the outer and inner bent positions (22, 23) or the crank (8) of the toggle lever (16) are positioned asymmetrically.   6. The drive system of a forming press according to claim 5, wherein a mirror program of the motion distribution of the even strokes of the ram (1) can be executed during all odd strokes of the ram (1).   The movement of the ram (1) can be locked by a separate, redundant braking device that is connected to or independent of the servomotor (5). The drive system for the molding press described. The drive system of a forming press according to claim 1, wherein the eccentric transmission and the crank transmission (14) respectively corresponding to the operating point (4 ) of the ram (1) are arranged symmetrically with respect to each other. The eccentric body transmission, the crank transmission (14) and the toggle lever (16) respectively corresponding to the operating point (4 ) of the ram (1) are arranged symmetrically with respect to each other. Drive system for molding press.   4. The intermediate circuit (26) of the servo amplifier (27) of the servo motor (5, 28) for the main and sub-movements of the forming press is directly coupled to one another. 2. A drive system for a molding press according to item 1.   13. The drive system for a forming press according to claim 12, wherein the drive for the tensioning device (28) acts as a secondary movement in the forming press.

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