METHOD FOR OPERATING AN ELASTICALLY MOUNTED FORMING MACHINE, IN PARTICULAR A PRESS

Abstract

A method for operating an elastically mounted forming machine which is path-bound or force-dependent, in which method a working stroke of a ram device operatively connected to the drive is initiated by means of a drive, and a predefined forming process is carried out on a workpiece by moving the ram device during said working stroke, in particular due to the interaction of an upper tool located on the ram device with a lower tool located on a tool table, wherein the inertial forces and/or moments of inertia occurring during operation owing to the initiation of the working stroke and/or owing to an imbalance in the drive are at least partially compensated. The method, wherein at least one kinematic variable (s(t),v(t),a(t)) of a rigid body motion of the elastically mounted forming machine is detected during the operation thereof, wherein the time at which the working stroke is initiated is adapted to an instantaneous phase position of the at least one kinematic variable (s(t),v(t),a(t)) of the rigid body motion in order to generate inertial forces and/or moments of inertia so as to counteract the rigid body motion of the forming machine.

Claims

1-14. (canceled)

15. A method for operating an elastically mounted, path-bound or force-controlled forming machine, in which a working stroke of a ram device operatively connected to a drive is carried out by means of the drive, and a predefined forming process is carried out on a workpiece by a motion of the ram device during the respective working stroke, in interaction of an upper tool located on the ram device with a lower tool located on a tool table, wherein: at least one kinematic variable (s(t), v(t), a(t) of a rigid body motion of the elastically mounted forming machine is detected relative to the supporting foundation during the operation thereof by at least one acceleration sensor and/or by a motion sensor located between a machine housing and the supporting foundation; the operation of the forming machine is controlled by a machine control; and an output signal of the at least one motion sensor for detecting the at least one kinematic variable (s(t), v(t), a(t)) of the rigid body motion of the forming machine is supplied as an input signal to a machine control for controlling the forming machine, wherein: the time of the initiation of the working stroke is adapted by the machine control to an instantaneous phase position of the at least one kinematic variable (s(t), v(t), a(t)) of the rigid body motion in order to generate inertial forces and/or moments of inertia so that the rigid body motion of the forming machine is counteracted and so that the inertial forces and/or moments of inertia occurring during operation due to the initiation of the working stroke and/or due to an imbalance in the drive are at least partially compensated; a coupling device located between the drive and the ram device is activated by the machine control at the time of the initiation of the working stroke and/or for establishing an operative connection between the drive and the ram device.

16. The method according to claim 15, wherein the time of clutch engaging the ram device or of the initiation of the working stroke is timed to a time period in the range of a global maximum of the first time derivation of the course of a rigid body deflection of the forming machine.

17. The method according to claim 16, wherein the initiation of the working stroke is carried out immediately before the first time derivation of the course of the rigid body deflection of the forming machine reaches the global maximum.

18. The method according to claim 15, wherein the at least one kinematic variable (s(t), v(t), a(t)) of the rigid body motion of the forming machine is detected by a motion sensor, that is located in a bearing device located between the supporting foundation and the forming machine.

19. The method according to claim 15, wherein the at least one kinematic variable (s(t), v(t), a(t)) of the rigid body motion of the forming machine is detected by an acceleration sensor that is located in a bearing device located between the supporting foundation and the forming machine.

20. The method according to claim 15, wherein the at least one kinematic variable (s(t), v(t), a(t)) of the rigid body motion of the forming machine relative to the supporting foundation is calculated on the base of a rigid body simulation model of the elastically mounted forming machine and the time of the initiation of the working stroke is defined depending on a calculated instantaneous value of the at least one kinematic variable.

21. The method according to claim 20, wherein at least one kinematic variable (s(t), v(t), a(t)) of the rigid body motion of the elastically mounted forming machine relative to the supporting foundation is measured and a synchronization signal is derived depending on the measurement signal and/or of an operation signal from a machine monitoring device, synchronization signal with which the time sequence of the kinematic variable calculated by means of the simulation model is synchronized with the real rigid body motion of the forming machine.

22. The method according to claim 15, wherein one variable of an elastic deformation movement of a predefined section of the forming machine relative to the housing of the forming machine is detected besides the at least one kinematic variable (s(t), v(t), a(t)) of the rigid body motion, wherein the time of the clutch engaging is adapted to an instantaneous phase position of the one variable of the deformation movement of the predefined section of the forming machine for generating inertial forces and/or moments of inertia during the clutch engaging so that the elastic deformation movement of the predefined section of the forming machine is counteracted.

23. The method according to claim 15, wherein a present amplitude value of an at least one kinematic variable (s(t), v(t), a(t)) of the rigid body motion of the forming machine is compared to a predefined threshold and a cycle rate of the forming machine is increased when the present amplitude value is lower than the predefined threshold.

24. The method according to claim 15, wherein the working stroke is initiated only under the additional condition of the event of a signaling triggered by an operator, in particular by a two-hand activation, for the working stroke to be initiated.

25. A forming device, in particular a press, comprising a drive and a ram device operatively connected to the drive for carrying out a working stroke, wherein a predefined forming process can be carried out on a workpiece by a motion of the ram device during the respective working stroke, in interaction of an upper tool located on the ram device with a lower tool located on a tool table, wherein: the at least one kinematic variable (s(t), v(t), a(t)) of the rigid body motion is detected by a motion sensor; an output signal of the at least one motion sensor is supplied to a machine control for controlling the forming machine for determining the at least one kinematic variable (s(t), v(t), a(t)) of the rigid body motion of the forming machine as an input signal, wherein the motion sensor that is located in a bearing device located between the supporting foundation and the forming device, that the forming machine is elastically supported on the supporting foundation by means of elastic bearing elements, that the machine control of the forming device is designed and configured for carrying out a method according to claim 15 and that a coupling device located between the drive and the ram device is provided for establishing an operative connection between the drive and the ram device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The invention shall be explained below with the description of an embodiment and of modifications thereof with reference to the accompanying drawings.

[0031] FIG. 1 shows a front view of a forming machine according to the invention as a press for carrying out the method according to the invention.

[0032] FIG. 2 shows a symbolic representation of a tilting/tumbling motion of the machine of FIG. 1.

[0033] FIG. 3 shows a process chart of an embodiment of the method according to the invention.

[0034] FIG. 4a shows the time sequence of a deflection s(t) and the time derivation thereof v(t) of the forming machine during the rigid body motion thereof in operation when carrying out the method according to the invention for a phase-optimized clutch engaging of the ram device according to the invention.

[0035] FIG. 4b shows a representation corresponding to FIG. 4a for a non phase-optimized clutch engaging of the ram device.

DETAILED DESCRIPTION

[0036] FIG. 1 shows in a front view the structure of an elastically mounted press 1 that is designed and configured according to the invention so as to carry out the method according to the invention for controlling the operation of an elastically mounted forming machine. This forming machine comprises a stand 2 that bears on a machine frame 3. A drive that comprises here an electric motor 4a and an oscillating mass 4b driven by the motor cooperates in the described embodiment with a ram device 5 or bear over a controllable coupling device, hidden in the figure, wherein an operative connection can be adjusted between the drive 4a, 4b and the bear 5 over the controllable coupling for carrying out the working stroke and can be disengaged for preparing the next working stroke. The ram device carries at its end an upper tool 6 that cooperates with a lower tool 7 that is located on the machine frame 3, for implementing a forming process of a workpiece that is not represented. The machine frame carries the drive and the bear via the stands 2 and bears itself on the foundation soil or on the supporting foundation 9 by means of several elastic bearing elements 8, each comprising in the described embodiment an elastomer body. In another embodiment, in particular in a path-bound forming machine, it can also be provided that the press comprises a drive with a servomotor that is rigidly connected to the ram device 5.

[0037] In all the embodiments of such forming machines, a tumbling and/or tilting motion of the press 1 is generally generated during the clutch engaging for connecting the drive and the ram device or during the initiation of the working stroke and/or during the carrying out of the working stroke, for example because of an imbalance in the drive, due to the respective occurring of inertial forces or moments in inertia.

[0038] For force-controlled forming machines, these inertial forces or moments of inertia that excite a rigid body motion of the forming machine can be generated in particular by an imbalance in the drive and insofar occur during the entire time range of a working stroke of the ram device of the forming machine. For path-bound forming machines, these inertial forces or moments of inertia that excite a rigid body motion of the forming machine can occur in particular during the clutch engaging of the coupling located between the drive and the ram device or during the initiation of the working stroke. In such cases in which the drive experiences an imbalance, additional excitation torques or excitation forces can occur.

[0039] FIG. 2 shows a symbolic representation of a possible tilting motion K of the press of FIG. 1 as a vibration. Possible modes of a rigid body motion of a vibratory system that is formed by the press 1 supported on the foundation soil 9 by the elastic bearing elements 8 can basically be excited.

[0040] As explained, the press of FIG. 1 is configured as a path-bound forming machine for which the inertial forces or moments of inertia that excite a rigid body motion of the forming machine are caused during the clutch engaging of the coupling for adjusting an operative connection between the drive and the ram device. The operation of the forming machine of FIG. 1 is controlled in the described embodiment by a machine control that controls, at the time of the initiation of the working stroke, the coupling device located between the drive and the ram device for establishing an operative connection between the drive and the coupling.

[0041] It is essential for carrying out the method according to the invention or the operation of the forming machine according to the invention that at least one kinematic variable of the rigid body motion, for example a deflection, of the elastically mounted forming machine 1 is detected during the operation thereof, is here measured by corresponding sensors as one or several motion sensors, wherein the time of the initiation of the working stroke, here the time for causing the operative connection between the drive and the ram device is adjusted in such a manner that the inertial forces and/or moments of inertia generated during the clutch engaging counteract the rigid body motion of the forming machine. In another embodiment, it can also be provided that the at least one kinematic variable of the rigid body motion, for example a deflection, is calculated by simulation of the rigid body motion of the forming machine, wherein an output signal of a motion sensor can be used for detecting the motion of the forming machine or another operating signal for the synchronization of the real motion of the forming machine with the simulation.

[0042] The method according to the invention for the phase-exact clutch engaging of the coupling of the press indicated in FIG. 1 is indicated in FIG. 3 and is carried out in the described embodiment by a central machine control of the forming machine. This being, it is started from the fact that the forming machine is in operating mode for which, after a release signal is available, in particular a two-hand activation signal induced by an operator, a working stroke of the ram device is initiated with the clutch engaging, working stroke during which a predetermined forming process is carried out on a workpiece in interaction of the ram device or of the upper tool carried thereby with a lower tool located on a tool table, wherein the ram device is returned in a subsequent return stroke, and the operative connection between the drive and the ram device is suppressed by clutch disengaging until a further working stroke is initiated by clutch engaging after a further release signal is available.

[0043] In the described embodiment, the clutch engaging is adapted to a phase position of a kinematic variable, here a deflection of the forming machine from the rest position. The starting point of the method steps indicated in FIG. 3 is an operating situation for which the drive is decoupled from the ram device and after a release signal is made available, the time of the clutch engaging is to be fixed, wherein the forming machine carries out a rigid body motion caused by preceding excitations that is carried out, depending on the embodiment, differently attenuated in particular because of damping properties of the bearing elements. It should be noted that when carrying out the method according to the invention with a fully automated forming machine, the checking for the presence of a release signal may be dispensed with.

[0044] In the method steps of FIG. 3, in step 100 the present deflection of the rigid body motion of the forming machine 1 is measured by a motion sensor, wherein the machine control is designed to check in step 110 if the first time derivation of the course of the deflection, i.e. if the speed is situated in the range of a global maximum of the rigid body motion. As far as this is not the case, there does not take place any clutch engaging of the ram device for adjusting an operative connection between the drive and the ram device; instead, a jump back to step 100 takes place, i.e. for carrying out a further measurement of the deflection of the forming machine. This measurement and check loop will run until the speed is situated in the range of the global maximum of the speed determined in the course indicated in FIG. 3 prior to the start so that an initiation of the working stroke substantially in phase opposition can take then place in step 120 with a phase-adapted introduction of the excited inertial forces and/or moments of inertia so that the present rigid body motion of the forming machine is counteracted. With the initiation of the working stroke in step 120, the carrying out thereof takes place in step 130 for carrying out a predetermined forming process; thereafter, the return stroke of the ram device and the disengagement of the operative connection between the ram device and the drive takes place in step 140 for preparing a further working stroke. As far as the end of operation is reached, the forming machine is stopped; otherwise a jump into the start of the measuring loop, i.e. to step 100, takes place.

[0045] Exemplary courses of the rigid body motion of the forming machine of FIG. 1 are indicated in the FIGS. 4a, 4b. This being, the respective upper graph shows the course of a deflection of the forming machine in operation and the lower time course shows the resulting speed of the deflection. In both figures, the time courses show prior to the time T0 or T0′ the rigid body motion of the forming machine 1, the operative connection between the drive and the ram device being disengaged, this resulting in a weakly damped vibration. At the time T0 or T0, a design-related and application-related excitation, here an approximately impact-type excitation, takes place over a time period (T1 - T0) or (T1′ - T0′) due to the establishing of the operative connection between the drive and the ram device via the clutch engaging of the coupling so that the vibratory system, that is formed by the forming machine 1 elastically mounted by means of elastic bearing elements 8 on the supporting foundation 9, receives excitation energy.

[0046] The representations of FIGS. 4a, 4b show the time courses during and after the introduction of inertial forces or moments of inertia during the clutch coupling of the ram device. The external excitation of the rigid body motion recognizably takes place for the courses of FIG. 4a at a time at which the speed of the rigid body motion is approximately maximal. Furthermore, the excitation occurs for generating an opposite-phase motion of the forming machine and results in a subsequent motion of the forming machine with a reduced amplitude. By contrast, FIG. 4b shows the result of an excitation that is identical with that of FIG. 4a, wherein however the time of the clutch engaging is indeed again situated after a global maximum of speed has been reached, but the excitation is carried out in phase with the present deflection so that, after the disturbance has subsided, there results a rigid body motion with a considerably higher amplitude compared to the situation of FIG. 4a.

[0047] The curves of FIGS. 4a and 4b show the efficiency of the method according to the invention and/or of the forming machine configured according to the invention for reducing a rigid body motion of the elastically mounted forming machine in operation. Depending on the embodiment, several excitations can also occur within an operating cycle of the forming machine at different times; in these cases the method according to the invention can basically also be applied for reducing a rigid body motion of the forming machine with the above described advantages.

TABLE-US-00001 List of reference numerals 1 Forming machine, press 2 Stand 3 Machine foundation, machine frame, machine housing 4a Electric motor 4b Oscillating mass 5 Ram device, bear 6 Upper tool 7 Lower tool 8 Elastic bearing element, bearing device 9 Foundation soil, supporting foundation K Tilting motion s Deflection, stroke v Speed T0, T0′ Time of initiation of a working stroke or adjustment of an operative connection between the drive and the ram device T1, T1′ Disengagement of the operative connection