WO2006045275A2

WO2006045275A2 - Drive system for a forming press

Info

Publication number: WO2006045275A2
Application number: PCT/DE2005/001871
Authority: WO
Inventors: Uwe Darr; Werner Brand; Frank Ulrich; Rainer Hedler; Steffen Schmidt
Original assignee: Müller Weingarten AG
Priority date: 2004-10-25
Filing date: 2005-10-20
Publication date: 2006-05-04
Also published as: WO2006045275A3; DE102004052007B4; DE102004052007A1

Abstract

The invention relates to a drive system for a forming press for either increasing the output rate for a defined power or reducing the output rate for said power, the number and sequence of strokes, speed and force profiles being freely programmable. Another problem of the invention is to provide a very compact drive system which allows for a small height of the head piece for the drive of the press. A final problem of the invention is to allow for the adjustment of tilt of the ram for forming presses having a plurality of working points. The solution to these problems is to combine the advantages of hydraulic presses with regard to free programmability of path, speed and force profiles with that of mechanical presses with regard to increased output, rigidity and path-bound reproducibility of the lower point of regression. The invention is characterized in that one or more electric drives as servomotors are used in the form of a direct drive or in combination with a linear converter arranged downstream thereof and act upon a five-point knee lever in such a manner as to allow, in addition to free programmability of path, speed and force profiles, a flexible utilization of path and/or force-bound sequences of movement.

Description

Drive system of a forming press

description

The invention relates to a drive system of a forming press having the features of the preamble of one of the claims 1 and 4.

State of the art

According to DE 14 52 772 A presses with mechanical drive are known in which a primary engine part consisting of engine, flywheel and clutch-brake combination, a secondary engine part with gear transmission for

Power distribution and each associated with the pressure points Hubgetriebe with lever mechanism follows. A change in the case of crank drives sinusoidal

Motion sequence is achieved here by the use of lever and joint drives. It is disadvantageous in this solution that in addition to the increased expenses for the above-mentioned elements of the primary and secondary engine part, the path and speed profile of the

Tappet is rigidly predetermined. According to JP 2001300778 A a servo-motor-driven press is known, in which a numerically controlled motor drives a central spindle, the spindle nut is connected via a toggle mechanism with the two pressure points. In this case, a first pair of levers on the one hand in each case hinged to the spindle nut and on the other hand in each case connected to a second pair of levers, whose second end is rotatably mounted fixed to the frame. In the common point of articulation of the first and second lever pair, the one end of a third pair of levers is additionally mounted, the other end is articulated in the plunger. The central spindle operates in reversing operation, wherein the reversing positions respectively correspond to the upper and lower reversal point of the plunger of the press. The joint action of the central spindle on the adjacent pressure points, the control of the tilting behavior of the plunger is limited. In addition, the vertically arranged central spindle requires an increased height. Since the direction of rotation of the spindle drive in the lower reversal point of the plunger takes place in the phase of high energy output, on the one hand, the power requirement is increased at a given number of cycles or limited the number of cycles at a given power.

This disadvantage also relates to a further servo-motor-driven press according to JP 2002103089 A, in which a separate spindle of one numerically controlled one

Motor is driven in combination with a

Knee lever acts on each a pressure point of the plunger. The lever connected to the spindle nut is articulated in the common pivot point of the upper and lower legs of the toggle lever, whereby in conjunction with the horizontal

Spindle assembly, the size of the ram stroke is limited. The disadvantage of the energetically unfavorable reversal position of the toggle mechanism in the lower reversal position of the plunger of the latter two solutions is avoided in the hydromechanical drive of DE 199 18 700 Al in that the hydraulic drive cylinder downstream kinematic chain in a simple piston stroke in each case a plunger double stroke causes upward and downward movement, wherein the reversing positions of the drive cylinder of the upper, not belonging to Umformphase reverse position of the plunger correspond. Due to the mechanical translation of the lever mechanism, the size of the drive cylinder is reduced compared to conventional hydraulic presses with remaining increased control and control engineering effort. The application of several hydraulic drive cylinder requires a mechanical synchronization of the pressure points of the plunger, whereby a j eden in each pressure point separately, independently controllable force application is not provided. The increasing length of the drive cylinders with larger rams affects the rigidity of the drive due to the oil compressibility.

Task and advantage of the invention

The invention has for its object to make a drive system for a forming press so that either increased drive speed for a given drive power or drive speed is reduced for a given number of cycles, the size and sequence of strokes, speed and force profiles is freely programmable. Furthermore, a short overall height of the head piece for driving the press is to be achieved with the most compact possible design become. For forming presses with several pressure points, the possibility of a tilt control of the ram should be created.

According to the invention the object is achieved by a drive system of a press with the features of each one of claims 1 to 4. Further detailed embodiments are described in claims 3 to 25.

The core idea of the invention is to combine the advantages of hydraulic presses with regard to free programmability of the travel, speed and force profiles with the advantages of mechanical presses with regard to increased productivity, rigidity and path-controlled reproducibility of the lower reversal point. It is essential to the invention that one or more electric drives act as a servomotor in the form of a direct drive or with a downstream linear converter on a five-point toggle so that in addition to the free programmability of path, speed and force profiles flexible use of path and / or force-related motion sequences is possible. In the case of a force-applied ram movement, the lower reversal point is controlled in analogy to hydraulic presses as a function of the programmed forces. In this mode, the simple stroke of the electric drive corresponds to a simple ram stroke, the reversing of the electric drive is carried out in the lower reversal point of the plunger. The high positioning accuracy and mechanical stiffness of the servo axis also allows a path-bound plunger movement with reversing the electric drive in the lower reversal point of the plunger. If the electric drive swings through the toggle lever in the lower reversal point of the plunger without stopping, in another mode of operation, the advantage of the path-controlled plunger movement of mechanical presses at high clock rates can be utilized. It is achieved with a simple stroke of the electric drive, a double ram stroke with forward and return stroke, which reduces energy consumption and the cycle rate of the press is increased. The use of larger ram strokes is achieved by the advantageous embodiment of the five-point toggle lever by means of spatially separated hinge points of the input and output end of the double lever with the formation of a translation. It is furthermore advantageous that the drive modules which can be designed from direct drives or servomotors with downstream linear converters, for example in the form of spindles, can drive several pressure points jointly by means of an intermediate power divider and can also be assigned separately to a pressure point. In the latter embodiment, it is advantageous that the individual pressure points respectively associated drive in the force and position control can be controlled separately, which on the one hand for parallel holding the plunger which can be developed due auserkittigem force attack tilting compensated and on the other hand, a target tilt can be achieved.

It is also essential to the invention that the energy balance of the press is improved by an exchange of energy takes place between the servomotor for the main movement of the plunger and other present in the press for secondary movements servomotors, for example for electric motor driven pulling means that in the cycle of movement during the braking phases in the Generator mode of the servo motors regenerated energy is fed into the servomotor located in the motor mode. This effect can also be achieved if several presses belonging to a press line are operated out of phase relative to the plunger movement and an energy exchange takes place between the servomotor associated with each press for the main movement.

In the case of conventional mechanical forming presses with a rigid path characteristic, it is necessary, with the claim of a high quality of incorporation of new tools, that a displacement and speed characteristic equivalent to the production presses can be used in the associated incorporation presses. For this purpose, currently predominantly hydraulic incorporation presses with high-speed drive can be used with a flexible path-time characteristic whose expenses for the reproduction of production presses are not insignificant. Since the servo-motor driven drive system combines the advantages of mechanical and hydraulic presses, a substantially identical forming press is available for incorporation purposes and production.

The inventions will be explained in more detail below with reference to exemplary embodiments. The accompanying drawing shows:

Fig. 1 Common servo spindle drive for a Quattro five-point toggle mechanism

Fig. 2 common servo spindle drive for a tandem five-point toggle mechanism in a first

design Fig. 3 Common servo spindle drive for a tandem five-point toggle mechanism in a second embodiment

Fig. 4 Separate direct drive with linear motors for a five-point toggle mechanism

Fig. 5 Separate servo spindle drive for a five-point toggle mechanism in the inner buckling position

Fig. 6 Separate servo spindle drive for a five-point toggle mechanism in the outer buckling position Fig. 7 Energy balance between servo drives for the main and secondary movement via intermediate circuit coupling

Fig. 8 diagram with movement and drive power for main and secondary movements

In the first embodiment of Fig.l the perspective section of a forming press is visible, the drive 2 is shown for reasons of simplicity without the associated frame. The drive is effected by means of knee lever 3 distributed to four pressure points (4) of the plunger 1, wherein the toggle lever 3 are each formed as a five-point toggle 25. The plunger 1 is shown in the left half in its upper stroke position and in the right half in its lower stroke position. The movement of the Quattro five-point toggle lever 25 is generated jointly by means of a central spindle drive. For this purpose, two spindles 7 are each driven by a servomotor 5 with an intermediate gear 6. The associated, not shown spindle nut is mounted in the slider 8 and causes the linear converter 15, the conversion of the rotational movement of the spindle 7 in a linear movement of the slider 8. The slider 8 serves as a power divider 19 for synchronous For this purpose, in each case a tab 12 is operatively connected on the one hand to the slider 8 and on the other hand to the first leg 10 of a double lever 9. The double lever 9 is mounted on the rack side respectively in the double lever bearing 16 in the head piece, not shown. The second leg 11 of the double lever 9 provides via the hinged connecting rod 13, the operative connection to the pressure points 4 in the plunger 1 ago. The toggle lever 3 serves as a power amplifier for the axial force generated by the torque of the servomotor via the spindle 7 in the slider, which assumes its extreme value in the region of the extended position 18 of the toggle lever 3 for generating the pressing force required for the forming process. Corresponding to the left half in the illustration of Fig.l take the toggle lever 3 in the upper stroke position of the plunger 1, an inner buckling layer 14, which adjusts as an acute angle between the second leg 11 and the connecting rod 13.

By means of the servomotors 5, a flexible travel and speed characteristic is programmable for the movement of the plunger 1, wherein the transmission ratio of the toggle lever 3 is taken into account. The position, speed and torque of the servo motors 5 is controlled by means of an NC controller 32 so that the desired movement and force curves can be achieved. It is essential that the motion sequences are generated in a first embodiment by means of guide shaft-controlled electronic cams, which specify the desired position of the plunger 1.

In an advantageous embodiment can be dispensed with a direct force or torque measurement by the desired torques of the servo motors 5 in response to the acceleration, transmission ratio and more Influencing variables, such as temperature and friction, are corrected and limited in such a way that the required force is achieved at the point of action on the tappet 1. With this drive design, it is possible that the forming press is on the one hand weggebunden operated with a defined lower return point, which is in the extended position 18 of the bell crank 3. On the other hand, in analogy to hydraulic presses the servo-driven forming press can be operated by force, by the force is limited control side in the extended position 18.

In a further embodiment, the axial force in the slider 8 can be generated by means of a direct drive 20 in the form of a linear motor 21. For this purpose, a plurality of linear motors 21 are used for power amplification in an advantageous manner so that several secondary parts 23 are mounted either in the slider 8 or in the frame and operatively connected to several primary parts 24 in the frame or slider 8.

FIG. 2 shows in the second exemplary embodiment a common servo spindle drive for a tandem five-point toggle mechanism 25. In the left half, the plunger 1 is in the upper stroke position. The right half shows the ram 1 in the area of the lower turning point. Several servomotors 5 drive via a centralized gear 6 a horizontally mounted pair of spindles 7, each having a left-handed in the left half and a right-handed thread in the right half. Each spindle 7 is connected via the separate sliders 8 with the five-point toggle mechanism 25 in operative connection. In contrast to the first embodiment, the toggle lever 3 is designed so that it swings through at the lower reversal point of the plunger 1 without support and thus takes advantage of the path-bound plunger movement to achieve a high clock rate. In this case, the toggle lever 3, as shown in the left half, with an inner and an outer buckling layer 14, 17 alternately the upper reversal point of the plunger 1. In this case, with a simple stroke of the slider 8 each have a double stroke of the plunger 1 with Vor - and return stroke reached. In this case, a significant advantage is that compared to the first embodiment, the plunger is not braked in the extended position 18 of the toggle lever during the phase of increased energy demand by the forming process. As a result of the swinging of the toggle lever 3 through the lower reversal point, the energy consumption is reduced.

The freely programmable servo motor 5 enables a flexible path characteristic. When swinging through the toggle lever 3, each with symmetrically positioned buckling layer 14, 17 of the forward and return stroke of the plunger 1 is the same size, with all odd-numbered strokes of the plunger 1, a mirror program of the motion profile of the even strokes is mobile.

In addition, it may be advantageous for the production of a Umformteiles that the pressing process per forming part takes place several times by the lower reversal point of the plunger 1 per pressing operation several times, suitably with different stroke, is passed. As a result of these different strokes, the outer and inner buckling layers 14, 17 are positioned asymmetrically. To use larger ram strokes, it is advantageous that the input and output ends of the double lever 9 are arranged spatially separated. These are the first and second legs 10,11 in the double lever 9 to each other at an obtuse angle.

It is also conceivable that the separate sliders 8 as Leistungsverzweiger 19 each drive two toggle 3, so that the plunger 1 is operatively connected to a Quattro five-point toggle 25.

A second embodiment of the tandem five-point toggle mechanism is shown in FIG. 3 in a perspective view. Here, the drive modules with the servomotors 5, gear 6, slider 8 and spindles 7 are each arranged laterally next to the head piece vertically in the region of the press stand 22 projecting downwards. The slider 8 is in analogy to the preceding embodiments with two toggle levers 3 in operative connection. In this embodiment, a reduced overall height of the forming press is achieved in a compact design. The following figures show drives 2 for forming presses with toggle levers 3, in which each pressure point of the plunger 1 is driven separately.

The embodiment shown in Fig. 4 shows two independently controllable pressure points 4, the five-point toggle mechanism 25 is driven in each case by a direct drive 20 designed as a linear motor 21. For this purpose, the tab 12 is hinged to the linear motor 21 belonging to the primary parts 24, which are in operative connection with the associated secondary parts 23. In addition to the effect a plurality of linear motors 21, the toggle lever 3 is used to increase the force on the pressure points 20.

A force acting on the pressure points 4 each separately servo spindle drive can be seen from Figures 5 and 6. 5 shows the position of the five-point toggle lever 25 in its inner buckling position 14, while the outer buckling layer 17 is shown in Fig. 6.

In the right and left next to the plunger 1 in the region of the press stand 22 arranged drive module drives the servo motor 5 via intermediate gear 6 acting as a linear transducer 15 spindle 7 at. The axially movable slider 8 transmits the movement in analogy to one of the preceding embodiments of the five-point toggle 25. Due to the individual, independent position and force control of the pressure points 4 parallel holding the plunger 1 is also possible with off-center force application. On the other hand, it is conceivable that a defined desired tilting of the plunger 1 during the pressing process is adjustable.

The essentially flywheel-free drives 2 by means of servomotors 5 can cause load fluctuations with not inconsiderable peak powers in the energy absorption from the supply network 29. One way to improve the energy balance of the forming press, is supported by Figures 7 and 8, described below. In addition to the servomotors 5 for the main movement of the plunger 1, further servomotors 28 for secondary movements in the forming press, such as drawing devices, are used. In the upper half of Fig. 8, the path-time characteristic with the phase-related positions for the Plunger 1 and the drive of the pulling device 28 shown. After the impact point of ram 1 on the drawing device, it is actively moved by the servomotors 5 of the plunger 1, wherein the associated drives 28 in the generator mode by braking apply the required force of the pulling device for the forming process. In this phase with the greatest energy requirement for the motor-driven servomotors 5 of the plunger 1 28 energy is fed back as a result of the generator-operated servomotors of the pulling device. Since the two servomotors 5 for the main movement and the drives for the pulling device 28 are coupled via their servo amplifiers 27 via a common intermediate circuit 26 according to FIG. 7, there is a movement between the servomotors 5 for the movement of the plunger 1 and the drives 28 for the pulling device energy exchange.

A further energy exchange can take place in the press cycle according to diagram Fig.8 in the phase of braking the servomotors for the plunger 1 to achieve the upper reversal point to the effect of the now fed back from the plunger 1 energy in the phase of run-up motor-driven drives for the pulling device 28 is supplied via the intermediate circuit coupling. The time-related courses of the motor-driven and regenerative drive powers can be seen in each case for the plunger 1 and the drives of the pulling device 28 from the two middle curves of the diagram according to FIG. The resulting drive power is shown in the lower curve. Through the energy exchange via the DC link coupling, the load fluctuations can be reduced. It is also possible that an energy exchange between several forming presses takes place by the Umformpressen belonging to a press line are operated in phase with respect to their plunger movement and the energy is exchanged between the servomotors 5 for the main movement.

LIST OF REFERENCE NUMBERS

1 pestle

2 drive 3 knee lever

4 pressure point

5 servomotor

6 gears

7 Spindle / spindle drive 8 Slider

9 double levers

10 first leg

11 second leg

12 tabs 13 connecting rods

14 inner buckling position of the toggle lever

15 linear transducers

16 double lever bearing

17 Outer buckling position of the knee lever 18 Range of the extended position of the toggle lever

19 power splitters

20 direct drive

21 linear motor

22 Press stand 23 Secondary section

24 primary part Five-point toggle mechanism Link circuit coupling Servo drive Drives for pulling device Supply network Supply module Axis controller NC control

Claims

claims

1. drive system of a forming press with a toggle mechanism for the movement of the plunger (1), with at least one servo motor (5) a plurality of pressure points (4) are driven together, characterized in that at least one servo motor (5) as a direct drive (20) a common power splitter (19) acts, which is connected to at least two toggle levers (3), wherein the

Direction change of the servo motor (5) either between a folded position (14, 17) and the range of the extended position

(18) or between an inner and outer buckling layer

(14, 17) of the toggle lever (3) takes place.

2. Drive system of a forming press with a toggle mechanism for the movement of the plunger (1), wherein at least one servo motor (5) a plurality of pressure points (4) are driven together, characterized in that at least one servo motor (5) via at least one downstream linear converter ^' (15) acts on a common power divider (19) which is connected to at least two toggle levers (3), wherein the change of direction of the servomotor (5) either between a folded position (14, 17) and the region of the extended position (18) or between an inner and outer buckling position (14, 17) of the toggle lever (3).

3. drive system of a forming press with a toggle mechanism for the movement of the plunger (1), wherein at least one servo motor (5) each have a pressure point (4) is driven separately, characterized characterized in that at least one servomotor (5) acts as a direct drive (20) on the toggle lever (3), wherein the direction change of the servomotor (5) either between a folded position (14, 17) or the region of the extended position (18) or between a inner and outer buckling position (14, 17) of the toggle lever (3).

4. drive system of a forming press with a toggle mechanism for the movement of the plunger (1), wherein at least one servo motor (5) each a pressure point (4) is driven separately, characterized in that at least one servo motor (5) via at least one downstream linear converter (15) acts on the toggle lever (3), wherein the direction change of the servomotor (5) either between a folded position (14, 17) and the region of the extended position (18) or between an inner and outer buckling position (14, 17) of the toggle lever (3).

5. Drive system of a forming press according to claims 1 and 3, characterized in that the direct drive (20) is designed as a linear motor (21).

6. Drive system of a forming press according to claims 2 and 4, characterized in that the linear converter

(15) is designed as a spindle drive (7).

7. drive system of a forming press according to claims 1 and 2, characterized in that as Leistungsverzweiger (19) a common slider (8) for at least two pressure points (4) is provided.

8. drive system of a forming press according to claim 7, characterized in that as Leistungsverzweiger (19) a common slider (8) for four pressure points (4) is provided.

9. drive system of a ümformpresse according to claim 6, characterized in that one or more centrally driven spindles (7) act on a common slider (8).

10. Drive system of a forming press according to claim 6, characterized in that one or more centrally driven spindles (7) act on at least two independent sliders (8).

11. Drive system of a forming press according to claim 6, characterized in that the spindle drive (7), consisting of at least one each provided with right- and left-handed thread pair of spindles, is arranged horizontally between the pressure points (4).

12. Drive system of a forming press according to claims 1 to 4, characterized in that the direct drive (20) each with or without power divider (19) or the servo motor (5) with downstream linear converter (15) each with or without power divider (19) vertically or obliquely in the region of the press stand (22) is arranged.

13. Drive system of a Ümformpresse according to claims 1 to 4, characterized in that when changing direction of the servomotor (5) between an outer and inner buckling position (14, 17) of the toggle lever (3) the size and sequence is freely programmable from Hubwegen.

14. Drive system of a forming press according to claim 13, characterized in that the outer and inner buckling position (14, 17) of the toggle lever (3) are symmetrically positioned.

15. Drive system of a forming press according to claim 13, characterized in that the outer and inner buckling position (14, 17) of the toggle lever (3) are positioned asymmetrically.

16. Drive system of a forming press according to claim 13, characterized in that in all odd strokes of the plunger (1), a mirror program of the movement profile of the even strokes of the plunger (1) is mobile.

17. Drive system of a forming press according to claims 1 to 4, characterized in that the movement of the

Tappet (1) by means of a redundant-acting, with the servo motor (5) coupled or independent braking device is blocked.

18. Drive system of a forming press according to claims 1 to 4, characterized in that the pressure points (4) respectively associated toggle lever (3) is arranged symmetrically to each other.

19. Drive system of a forming press according to claims 1 to 4, characterized in that the aspect ratio of the second and first legs (11, 10) of the double lever (9) of the bellcrank (3) is greater than one,

20. Drive system of a forming press according to claim 5, characterized in that the plurality of linear motors (21) respectively assigned, in the slider (8) mounted secondary parts (23) are operatively connected to the frame side mounted primary parts (24).

21. Drive system of a forming press according to claim 5, characterized in that the plurality of linear motors

(21) respectively associated, in the slider (8) mounted primary parts (24) with the frame side mounted secondary parts (23) are operatively connected.

22. Drive system of a forming press according to claims 1 to 4, characterized in that the toggle lever (3) as a five-point toggle mechanism (25) is formed, the double lever (9) has a first leg (10) and a second leg (11) ,

23. Drive system of a forming press according to claims 22, characterized in that the first and second legs (10, 11) of the double lever (9) form an obtuse angle.

24. Drive system of a forming press according to claims 1 to 4, characterized in that the intermediate circuits

(26) the servo-amplifiers (27) are directly coupled together by the servomotors (5, 28) for the main and sub-movements of the forming press.

25. Drive system of a forming press according to one of claims 1 to 4, characterized in that in the Forming press act as a secondary movement of the drives for pulling devices (28).