JP5650232B2 - Machine tool press drive device and processing method - Google Patents

Description

  The present invention is a press drive device for a machine tool for generating a work stroke of a tool holding unit, in which a workpiece is loaded by a tool (tool such as a die) supported by the tool holding unit. The press drive unit and the first pressure element are provided, and the tool holding unit is loaded by the press force provided by the press drive unit by the first pressure element, Furthermore, a second pressure element is provided, and the tool holding unit is loaded by the additional pressing force provided by the press driving unit by the second pressure element, and only the first pressure element is provided. When loading the tool holder, the tool holder and the second pressure element are relatively movable. Scan drive on.

  Furthermore, the present invention relates to a machining method for generating a working stroke of a tool holding portion by a press drive device of a machine tool.

  Japanese Patent Application Laid-Open No. 2001-009538 describes a turret punch press provided with a press drive device of the type described at the beginning. This known prior art press drive device has a first striking portion (first striker), by which a tool assembly such as a mold supported on an upper tool turret is provided. It comes to be loaded. Under the load from the first striking portion, one tool supported by the tool assembly is moved along the stroke axis in the direction of the metal sheet to be processed. The first striking pressure portion is driven by a first piston cylinder driving device. In addition, the turret punch press is provided with a second striking pressure portion (second striker). The tool assembly is additionally loaded by the second pressing portion. This second striking pressure portion is driven by the second piston cylinder unit.

  The press drive device described in JP 2001-009538 A can be operated in three types of operation modes. In the first operating mode, only the first striking pressure portion loads the tool assembly, thereby generating a working stroke. The second striking pressure portion remains unmoved during the working stroke in the first operating mode.

  In the second operating mode, only the second striking part loads the tool assembly and the first striking part remains unmoved during the working stroke.

  Furthermore, in the case of the third operation mode, both the first and second striking pressure portions simultaneously load the tool assembly. Setting in which mode the press driving device is operated is performed based on an estimation of a pressing force required before workpiece processing.

  The problem imposed on the present invention is to provide a press drive device that can flexibly respond to the actual situation by improving the press drive device of the machine tool of the type described at the beginning. . Furthermore, the subject of this invention is providing such a processing method.

  According to the present invention, the object of the present invention is to generate a work stroke of the tool holding part in which the workpiece is loaded by the press driving device according to claim 1, that is, the tool supported by the tool holding part. A press drive device of a machine tool for providing a press drive unit and a first pressure element, and a tool holding unit provided by the press drive unit by the first pressure element. And a second pressure element is provided so that the tool holding portion is loaded by the additional pressing force provided by the press drive portion by the second pressure element. When only the first pressure element loads the tool holder, the tool holder and the second pressure are In a press drive device of a type that is relatively movable with respect to the element, when the tool holding portion is loaded only by the first pressure element, the tool holding portion and the second pressure element may be It is solved by a press drive device of a machine tool, characterized in that the tool holding part is loaded with an additional pressing force by the second pressure element by interfering with, in particular, eliminating the relative mobility. The

  Further, the object is to generate a work stroke of the tool holder by the machining method according to claim 16, that is, the press drive device of the machine tool, and at the time of the work stroke, the work is carried out by the tool supported by the tool holder. In the processing method that loads the tool holder, the relative mobility between the tool holder and the second pressure element is increased as necessary while the tool holder is loaded only by the first pressure element under the introduction of the pressing force. This is solved by a machining method characterized in that it is obstructed, in particular eliminated, whereby the tool holding part is loaded with an additional pressing force by means of a second pressure element.

  According to the present invention, it is possible to load the tool holding portion only with the first pressure element. Only when the need arises, i.e. when the pressing force provided by the first pressure element is insufficient to carry out the desired workpiece machining, the second pressure element can be connected. . The second pressure element loads the tool holder with an additional pressing force. According to the invention, the connection of the second pressure element is effected by interfering with, in particular, eliminating the relative mobility between the tool holding part and the second pressure element.

  According to the invention, the second pressure element is used only when it is found that it is actually necessary. Based on the relative mobility of the tool holder and the second pressure element, the second pressure element can not be moved during the working stroke if it is not required for the introduction of the pressing force, or at least It can only be moved at a lower speed than the tool holder. Unnecessary acceleration of the second pressure element is avoided. Therefore, the mass that must be moved or accelerated is only the size that is actually required. Thereby, on the one hand, the energy consumption of the press drive device can be reduced, and on the other hand, the dynamic characteristics can be improved while the drive output of the press drive device remains the same.

  Another advantage of the present invention is the increased functional reliability of the press drive. In the case of the known prior art, in some cases, the required pressing force may be underestimated. The working stroke ends when the tool holder is only loaded by the first pressure element, even though the pressing force provided by the first pressure element is insufficient to carry out the workpiece machining Can not be made. As a result, workpiece machining must be interrupted. On the other hand, according to the present invention, the second pressure element can be connected (later) to complete the workpiece machining.

  Furthermore, the press force estimation required in the known prior art can be made unnecessary based on the fact that the second pressure element can be connected during workpiece machining.

  Advantageous embodiments of the invention according to claim 1 are described in claims 2 to 15.

  In the case of the configuration of the present invention according to claim 2, the second pressure element and the tool holding portion are relatively movable along the work stroke axis, and the press drive device is arranged along the work stroke axis. Thus, the working stroke of the tool holding part can be formed. That is, the second pressure element is moved in the stroke direction at a lower speed than the tool holding portion while the tool holding portion is moved along the working stroke axis only in the stroke direction by the first pressure element during the working stroke. be able to. In particular, the second pressure element may remain unmoved in the stroke direction. The energy saving possibilities already described above are obtained on a special scale.

  On the contrary, the second pressure element can be moved in the direction opposite to the stroke direction in the working stroke of the tool holder generated by the first pressure element. In this way, the second pressure element can be moved to the starting position for the subsequent work stroke before the work stroke is completed. Therefore, the process time can be shortened because the press drive is more quickly prepared for the next work stroke after the work stroke is completed.

  In the configuration according to claim 3, the tool holding part is added by the second pressure element by preventing or eliminating the relative mobility between the tool holding part and the second pressure element only in one direction. Loaded by pressing force. In order to be able to introduce the additional pressing force, the second pressure element loads the tool holder with the additional pressing force, and at least the relative mobility in the direction of introducing the pressing force is hindered or eliminated. . However, in the configuration described in claim 3, in the direction opposite to the pressing force introduction direction, the relative mobility is maintained even when the force is introduced by the second pressure element. Therefore, the motion coupling between the tool holder and the second pressure element can be performed only on a necessary scale.

  In an advantageous configuration as claimed in claim 4, the relative movement between the tool holder and the second pressure element is hindered by the connecting stroke in which the relative movement between the tool holder and the second pressure element takes place. Or it is eliminated. If the second pressure element is moved toward the tool holder in the stroke direction during the connecting stroke, the second pressure element can be accelerated in the stroke direction before the additional press force is introduced. Then, when the movement of the accelerated second pressure element is impeded or eliminated, the drive output applied to the second pressure element accelerates or loads the tool holder in the stroke direction. Enough to provide. The drive output component required to accelerate the second pressure element after connection of the second pressure element is reduced.

  The length of the connecting stroke is advantageously set such that the second pressure element can be accelerated to the desired pressing speed in the stroke direction during the connecting stroke. In that case, the drive output is completely provided to load the tool holder.

  In the structure of Claim 5, the contact surface provided in the 2nd pressure element with the connection stroke contact | abuts the contact surface provided in the tool holding part side, A tool holding part and 2nd The relative mobility with the pressure element can be eliminated. A robust and functional variation of the force / motion coupling can be obtained.

  Since the first pressure element is fixedly coupled to the tool holder along the working stroke axis (Claim 6), the first pressure element always introduces a pressing force into the tool holder without time delay. be able to. Furthermore, since the first pressure element is firmly coupled to the tool holding portion along the work stroke axis, the tool holding portion can be moved by the first pressure element in the return stroke following the work stroke. . There is no need to provide additional return means, for example a return spring.

  In the case of the configuration described in claim 7, the press drive device has a first drive unit corresponding to the first pressure element. Further, the press drive unit is provided with a second drive unit corresponding to the second pressure element. The pressure elements can be moved independently of one another by various drive units. The flexibility of the press drive device is further improved.

In particular, the drive unit can be designed in various ways. For example, the first drive unit may have a particularly high dynamic characteristic (eg maximum acceleration up to 100 m / s ² ) and at the same time a relatively low maximum force (eg maximum force of 40 KN). The second drive unit may be designed to provide a higher acceleration (for example a maximum acceleration of 160-250 KN) while providing a lower acceleration value (for example a maximum acceleration of up to 10 m / s ² ). Thus, overall, a highly dynamic, ie highly dynamic press drive that can provide a higher pressing force is obtained.

  If a relatively low pressing force is required, such as when punching a relatively thin metal sheet, the working stroke can be generated only by a highly dynamic drive unit. In this case, for example, at a step width of 1 mm, i.e. between two strokes, a stroke number of 1500 hits per minute can be achieved if the metal sheet is moved by 1 mm each relative to the tool. The additional pressing force is introduced by the second drive unit only when necessary, for example only when stamping a relatively thick metal sheet.

  Various drive structures are conceivable for the drive unit. For the first drive unit, a gearless or non-transmission piezo drive is advantageous due to its high dynamic characteristics. However, it is the relatively short stroke length that is disadvantageous in the gearless piezo drive. In contrast, inductive linear drives, in particular “tube motors”, are distinguished by particularly high dynamic properties and relatively long stroke lengths. If the second drive unit is further configured as an electrical drive unit, for example as an electrical spindle drive unit, an overall electrically driven press drive device is obtained (claim 8). . In this case, the hydraulic drive technology can be abandoned. For this purpose, it is particularly advantageous if the drive unit corresponding to the first pressure element is configured as an electrical spindle drive or an inductive linear drive (claim 9).

  In the variation according to the tenth aspect, the tool holding portion is provided in the plunger, and a pressure element for introducing a pressing force acts on the plunger. As a result, the pressure element can be coupled in the immediate vicinity of the drive unit. In this way, an advantageous situation for introducing the pressing force is obtained.

  The embodiments of the invention as claimed in claims 11 to 13 are distinguished by a particularly advantageous construction of the press drive. In this case, the plunger is arranged in a particularly space-saving manner in an axial housing provided on the drive spindle.

  In the configuration of the fourteenth aspect, a rotation drive unit is provided, and the rotation of the tool holder can be adjusted around the work stroke axis by the rotation drive unit. Based on the possibility of adjusting the rotation of the tool holder, the tool supported in the tool holder can be rotated in a desired direction relative to the workpiece for workpiece processing. In a particularly compact structure, for example, a rotary shifter cooperates with the second pressure element in order to entrain the tool support around the working stroke axis. However, as an alternative, the rotary shifter may be arranged separately from the second pressure element, which makes it possible to design a press drive that can be particularly advantageous in terms of the stability of the press drive. Is obtained.

  The press driving device is configured such that when the prescribed pressing force introduced to the tool holding unit by the first pressure element is exceeded, the additional pressing force is automatically introduced to the tool holding unit by the second pressure element. It may be configured.

  In the configuration according to the fifteenth aspect, the detection means is provided, and this detection means can detect whether or not it is necessary to introduce the additional pressing force when the workpiece is loaded. The detection means may be formed by a stroke sensor and / or a force sensor. In an inexpensive variant without additional sensors, only the current consumed by the electrical first drive unit is measured. Since the current consumption is a measure of the force provided by the drive, estimating that the connection of the second pressure element is necessary if a predefined limit value of the current consumption is exceeded. Can do. As soon as the need is detected, the press drive is controlled so that the second pressure element is connected to introduce the press force.

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

It is a side view of the punching / molding machine provided with the press drive device. It is sectional drawing of the press drive device of a 1st structure. It is sectional drawing which shows the press drive device shown in FIG. 2 in the 1st step at the time of the punching process of a thin metal sheet. It is sectional drawing which shows the press drive device shown in FIG. 2 in the 2nd step at the time of the punching process of a thin metal sheet. It is sectional drawing which shows the press drive device shown in FIG. 2 in the 3rd step at the time of the punching process of a thin metal sheet. It is sectional drawing which shows the press drive device shown in FIG. 2 in the 1st step at the time of the punching process of a thick metal sheet. It is sectional drawing which shows the press drive device shown in FIG. 2 in the 2nd step at the time of stamping of a thick metal sheet. It is sectional drawing which shows the press drive device shown in FIG. 2 in the 3rd step at the time of the punching process of a thick metal sheet. It is a flowchart which shows the method step of the processing method using the press drive device shown in FIG. It is sectional drawing of the press drive device of a 2nd structure. FIG. 6 is a diagram showing the relationship between the speed of a driving spindle of the press driving device shown in FIG. 5 and the elapsed time of controlled workpiece processing. FIG. 8 is a diagram showing the relationship between the speed of the driving spindle of the press driving device shown in FIG. 5 and the elapsed time of workpiece processing controlled differently from the case of FIG. 7. FIG. 9 is a diagram showing the relationship between the speed of the drive spindle of the press drive device shown in FIG. 5 and the elapsed time of workpiece machining controlled differently from the case of FIGS. 7 and 8.

  FIG. 1 shows a machine tool in the form of a punching / molding machine 1. The punching / molding machine 1 has a C-shaped machine frame 2. A general-purpose coordinate guide 4 is arranged in the chamber 3 corresponding to the open mouth of the C-shaped machine frame 2. A metal sheet (metal thin plate) 5 to be processed can be fixed to the coordinate guide 4. The machining unit 6 disposed on the upper frame jaw of the machine frame 2 includes a press drive device 7, a tool holding unit 8, and a machining tool (tool) 9 supported on the tool holding unit 8. .

  In order to process the metal sheet 5 by the punching / molding machine 1, a portion to be processed of the metal sheet 5 is arranged under the processing tool 9 by the coordinate guide 4. The tool holder 8 including the processing tool 9 is subsequently lowered onto the metal sheet 5 in the stroke direction 11 by using the work stroke along the work stroke axis 10 by the press drive device 7.

  Metal sheet processing, for example, punching, is performed by a processing tool 9 that loads the metal sheet 5 with a pressing force or a punching force. In this case, the machining tool 9 cooperates with a second machining tool (not shown) disposed on the opposite side of the metal sheet 5 during machining. After completion of the working stroke, the machining tool 9 is lifted in the return stroke direction 12 along the working stroke axis 10.

  By means of the press drive device 7, the tool holding part 8 can be rotated and adjusted around the working stroke axis 10 together with the processing tool 9.

  As the processing tool (tool), in addition to the punching tool, a molding processing tool, for example, a stamping processing tool, a bending processing tool, an embossing tool, and the like can be inserted into the tool holding portion 8 in a replaceable manner.

  All the drive units of the punching / molding machine 1 are controlled by a numerical control unit 13.

  The press drive device 7 of the punching / molding machine 1 is shown in detail in FIG. The tool holder 8 is fixedly coupled to the elongated plunger 14. The longitudinal axis of the plunger 14 coincides with the working stroke axis 10.

  A first drive unit in the form of a highly dynamic linear motor 15 is provided at the end of the plunger 14 opposite to the tool holding portion 8. The linear motor 15 forms a part of the press drive unit of the press drive device 7. An annular secondary portion 17 of the linear motor 15 is also arranged inside the annular primary portion 16 that extends annularly about the work stroke axis 10 of the linear motor 15. The measuring device 18 makes it possible to measure the current required by the linear motor 15.

  The secondary part 17 is provided with a dish-shaped pressure element 19. The pressure element 19 is rotatable about the working stroke axis 10 by means of an axial rotary bearing 20, but is fixedly coupled to the plunger 14 in the axial direction. In an alternative configuration, an additional damping element may be provided between the pressure element 19 and the plunger 14.

  In a further alternative configuration, a linear motor in the form of a so-called “tube motor” can be used instead of the illustrated linear motor 15. A “tube motor” is characterized by a cylindrical structure, which allows the secondary part of the motor to rotate about the stroke axis indefinitely relative to the primary part. It makes it possible to carry out highly dynamic strokes in the relative rotational position. Therefore, when the “tube motor” is used, the rotary bearing 20 can be eliminated, which is advantageous.

  Further, the press drive device 7 has a second drive unit as a part of the press drive unit, and the second drive unit is formed as an electrical rotation / lifting drive device. This rotation / lifting drive device is formed by an electrical spindle drive device 21. The spindle drive 21 is not configured as dynamically as the linear motor 15, but can provide a significantly higher pressing force than the linear motor 15.

  The spindle drive device 21 has a drive spindle 22. The spindle axis of the drive spindle 22 coincides with the work stroke axis 10. The drive spindle 22 is provided with two male threads 23, 24. Both male threads 23, 24 have the same thread pitch but are formed in opposite directions. A first drive nut 25 is attached to the first male screw thread 23, and a second drive nut 26 is attached to the second male screw thread 24. The rotational positions of the drive nuts 25 and 26 around the work stroke axis 10 can be measured by the sensor 27.

  A torque motor 28 is disposed corresponding to the first drive nut 25. The torque motor 28 includes a frame-fixed stator 29 and a rotor 30. The rotor 30 is formed in an annular shape around the work stroke axis 10 and is coupled to the first drive nut 25 in a gearless manner, that is, without a transmission. The stator 29, the rotor 30, and the first drive nut 25 at least partially overlap each other along the work stroke axis 10. A torque motor 31 is disposed corresponding to the second drive nut 26. The torque motor 31 has the same structure as the torque motor 28. The torque motor 31 includes a frame-fixed stator 32 and a rotor 33 that is fixedly coupled to the second drive nut 26.

  The drive spindle 22 includes an axial accommodating portion 34. The plunger 14 is disposed in the housing portion 34. In particular, the plunger 14 penetrates the drive spindle 22 in the axial direction.

  The axial accommodating portion 34 provided on the drive spindle 22 has a small diameter section so as to form a cylindrical step portion 39. The inner peripheral surface of the cylindrical step portion 39 includes two guide grooves 36 that are located opposite to each other in the radial direction. These guide grooves 36 extend in the plane of the cross-sectional view shown in FIG. That is, FIG. 2 shows the inner diameter of the cylindrical step portion 39 in the inner peripheral surface range where the guide groove 36 is located. In the inner peripheral surface range where the guide groove 36 is not located, the inner diameter of the cylindrical step portion 39 substantially corresponds to the outer diameter of the plunger 14 (not known from FIG. 2). In the axial guide groove 36 provided on the inner peripheral surface of the cylindrical step portion 39, two entraining fins 35 that are fixedly coupled to the plunger 14 protrude.

  In a variation (not shown) of the press drive unit, the guide groove 36 may be provided in another axial section of the storage unit 34 separated from the cylindrical step 39. In this case, the guide groove 36 may be arranged so as to be shifted upward as viewed in FIG. Correspondingly, in the case of such a variation, the entraining fins 35 are also arranged on the upper side compared to the state shown in FIG. In this case, the entraining fin 35 is guided in the guide groove 36 of the drive spindle 22 with a larger radial mutual distance, so that the drive spindle 22 and the plunger 14 can be guided more stably. Shape is obtained.

  Furthermore, in the press drive device 7 shown in FIG. 2, the cylindrical step portion 39 has an annular contact surface 37 on the end surface on the tool holding portion side. The plunger 14 has an annular introduction surface 38 so as to face the contact surface 37 in the axial direction, and the introduction surface 38 is formed by a radial step provided on the plunger 14.

  In order to determine the axial position of the plunger 14 or the tool holder 8 relative to the machine frame 2 and to determine the rotational position of the plunger 14 or the tool holder 8 around the work stroke axis 10, the sensor 39a is used. work.

  Below, the general functional form of the press drive device 7 is demonstrated. Subsequently, the individual motion sequences during various workpiece machining will be described with respect to FIGS. 3a, 3b and 3c and FIGS. 4a, 4b and 4c.

  In order to raise or lower the plunger 14 along the working stroke axis 10 by the linear motor 15 together with the tool holding portion 8 and the processing tool 9 supported by the tool holding portion 8, The secondary part 17 carries out a corresponding up or down movement along the working stroke axis 10 relative to the primary part 16 of the linear motor 15 fixed to the frame. The stroke movement of the secondary part 17 is transmitted to the plunger 14 via the pressure element 19 and the axial rotary bearing 20. Similarly, the force formed by the linear motor 15 can be introduced into the plunger 14 in the stroke direction 11 and the return stroke direction 12.

  During the stroke movement of the plunger 14 by the linear motor 15, the entraining fin 35 provided in the drive spindle 22 and the axial guide groove 36 form a rotation preventing means for the plunger 14.

  Furthermore, the plunger 14 can be rotated and adjusted around the work stroke axis 10 by the spindle driving device 21. Therefore, the spindle drive device 21 forms a rotation drive unit, and the rotation drive unit enables the tool holding portion 8 provided on the plunger 14 to be rotated and adjusted around the work stroke axis 10. In order to move the plunger 14 together with the tool holder 8 to a predetermined rotational position around the work stroke axis 10, the work spindle 22 is rotated around the work stroke axis 10. The entraining fin 35 functions as a rotation shifter, and the rotation shifter causes the plunger 14 to rotate together with the tool holding portion 8 during the rotational movement of the drive spindle 22 around the work stroke axis 10. The rotational movement of the drive spindle 22 is obtained without the drive spindle 22 also performing a stroke movement along the working stroke axis 10, in which case the drive nuts 25, 26 are torque motors at equal speed and in the same direction. Rotated by 28 and 31.

  Furthermore, the plunger 14 can be lowered in the stroke direction 11 by the spindle drive 21 or can be loaded with an (additional) pressing force in the stroke direction 11. For this purpose, the drive spindle 22 is lowered in the stroke direction 11. The downward movement of the drive spindle 22 is generated without the drive spindle 22 being rotated simultaneously. In this case, both drive nuts 25, 26 are rotated by torque motors 28, 31 at equal speeds but in opposite directions. When the contact surface 37 provided on the cylindrical step portion 39 is pressed in the stroke direction 11 against the introduction surface 38 provided on the plunger 14, the (additional) press force generated by the spindle driving device 21 is applied to the plunger. 14 may be introduced.

  Therefore, the cylindrical step portion 39 serves as a pressure element that can load the plunger 14 and thus the tool holding portion 8 with the (additional) pressing force provided by the spindle driving device 21.

  3a to 3c show three different operating states of the press drive device 7 when a relatively thin metal sheet 5 is stamped. In the punching process shown in FIGS. 3 a to 3 c, a required pressing force or punching force is formed only by the linear motor 15.

  FIG. 3 a shows the press drive 7 in an operating state in which the tool holder 8 occupies the starting position before the work stroke. Starting from this starting position, the tool holding portion 8 is fed together with the machining tool 9 onto the metal sheet 5 in the stroke direction 11. The axial movement of the processing tool 9 is performed by a linear motor 15. The spindle drive 21, in particular the drive spindle 22, along with the radial step 39, remains stopped during the stroke movement. As a result, the tool holding portion 8 moves in the direction away from the cylindrical step portion 39 in the stroke direction 11 starting from the state of FIG. The tool holding portion 8 and the cylindrical step portion 39 perform relative movement along the work stroke axis 10.

  FIG. 3 b shows a state when the processing tool 9 is just placed on the metal sheet 5. The work stroke division in which the machining tool 9 only approaches the metal sheet 5 has been completed. The drive spindle 22 remains in the same position as the position where the drive spindle 22 was located at the start of the working stroke (FIG. 3a), so that the axial direction between the contact surface 37 and the introduction surface 38 is The interval is increased based on the downward movement of the plunger 14.

  During the subsequent punching process, the processing tool 9 loads the metal sheet 5 with a predetermined pressing force in the stroke direction 11. The pressing force or punching force when the processing tool 9 loads the metal sheet 5 is provided by the linear motor 15. For this purpose, a pressure element 19 connected to the secondary part 17 of the linear motor 15 loads the plunger 14 with a pressing force. A pressing force is applied to the processing tool 9 through the plunger 14 and the tool holding portion 8. In the illustrated case, the metal sheet is a relatively thin metal sheet 5, so that the maximum pressing force (about 40 KN) that can be provided by the linear motor 15 is sufficient to completely punch the metal sheet 5.

  FIG. 3 c shows the operating state of the press drive device 7 after the processing tool 9 has completely punched the metal sheet 5. Starting from this state, the plunger 14 is moved by the return stroke toward the starting position shown in FIG. The spindle drive 21 remains unmoved during the working stroke and during the return stroke.

  Based on the high dynamic characteristics of the linear motor 15, the punching process described above can be performed in a very short time. Therefore, particularly in a thin metal sheet region, a maximum of 1500 hits can be achieved at a step width of 1 mm using the press drive device 7. Stroke counts up to / min can be achieved.

  4a to 4c show three different operating states of the press drive device 7 when a relatively thick metal sheet 5 is stamped.

  FIG. 4 a shows a state when the processing tool 9 is just mounted on the metal sheet 5. Therefore, the state in FIG. 4a corresponds to the state from FIG. 3b. The pressing force when the processing tool 9 loads the metal sheet 5 is initially provided only by the linear motor 15. Correspondingly, the plunger 14 and thus the tool holding part 8 are also loaded with a pressing force only by the dish-shaped pressure element 9.

  However, the maximum pressing force that can be formed by the linear motor 15 is insufficient to completely punch out the relatively thick metal sheet 5. Whether additional press force is required is required. In this case, the current required by the linear motor 15 is measured by the measuring device 18 (FIG. 2), and the measured value is constantly transmitted to the numerical control unit 13. In the evaluation part of the control unit 13, the measured current is compared with the current limit value. This current limit value corresponds to the current consumed by the linear motor 15 at the maximum pressing force that can be provided by the linear motor 15. When the measured current reaches a specified limit value, the numerical control unit 13 evaluates this as a case where it is necessary to introduce an additional pressing force using the spindle drive 21. As a result, the measuring device 18 and the previously described evaluation part of the numerical control unit 13 form detection means for determining whether the introduction of an additional pressing force is necessary.

  Subsequently, the numerical control unit 13 releases the connecting stroke. In this connection stroke, the drive spindle 22 is moved by the torque motors 28, 31 in the stroke direction 11 together with the cylindrical step 39. The stroke length of the connecting stroke is sufficient to enable the spindle drive device 21 to be accelerated to the speed (pressing speed) when performing subsequent workpiece machining during the connecting stroke together with the cylindrical step 39. It becomes.

  When the contact surface 37 contacts the introduction surface 38, the connection stroke is terminated. The cylindrical step portion 39 and the tool holding portion 8 can no longer approach each other along the work stroke axis 10. Therefore, the relative mobility between the cylindrical step portion 39 and the tool holding portion 8 is eliminated in one direction along the work stroke axis 10. The situation shown in FIG. 4b is produced.

  At the time of subsequent workpiece machining, an additional pressing force is introduced to the tool holding portion 8 through the introduction surface 38 provided on the plunger 14. This additional pressing force is generated by the spindle driving device 21. Since the spindle drive 21 has already been accelerated to the press speed with the cylindrical step 39 before the contact surface 37 abuts the introduction surface 38, the spindle drive 21 no longer needs to be accelerated any further. . Therefore, the drive output of the spindle driving device 21 is to completely accelerate the plunger 14, the tool holding unit 8 and the machining tool 9, and to load the plunger 14, the tool holding unit 8 and the machining tool 9 with an additional press force. Is provided.

  The pressing force provided by the linear motor 15 and the additional pressing force provided by the electric spindle driving device 21 are added up. The sum of these pressing forces is sufficient to completely punch the relatively thick metal sheet 5. The state after the metal sheet 5 has been completely punched is shown in FIG. 4c.

  After the working stroke, the working tool 9 is lifted again to the starting position (FIG. 3a) by a return stroke or a return stroke. In this case, the linear motor 15 and the spindle driving device 21 simultaneously move in the return stroke direction 12. Depending on circumstances, the speed of the machining tool 9 at the time of the return stroke is limited by the speed of the lower spindle driving device 21.

  However, there may be situations where the direction of movement of the spindle drive 21 can be reversed before the end of the working stroke. For example, in the lower section of the working stroke, there can be mentioned workpiece machining in which a pressing force smaller than the pressing force that can be provided at maximum by the linear motor 15 is required. In this case, pulling back of the low-speed spindle drive device 21 can be started before the end of the work stroke. Therefore, the speed of the machining tool 9 in the subsequent return stroke is determined only by the higher linear motor 15. That is, the machining tool 9 can be pulled back more quickly, and the time for the return stroke is shortened.

  As a precaution, the spindle drive device 21 is connected not only when the machining tool 9 is mounted on the metal sheet 5, but also during the machining of all workpieces or during the work stroke. obtain.

  FIG. 5 once again summarizes the three main method steps within the framework of the stamping process described with reference to FIGS. First, the tool holder 8 is loaded only by the first dish-shaped pressure element 19 and a pressing force is introduced (FIG. 4a). If necessary, a second pressure element, in this case a cylindrical step 39, is connected for the introduction of an additional pressing force by means of a connecting stroke relative to the tool holder 8. Furthermore, the tool holding part 8 is loaded by the second pressure element and an additional pressing force is introduced (FIG. 4b).

  The numerical control unit 13 of the punching / molding machine 1 enables the press drive device 7 to be operated in two types of control modes. In the basic control mode, the press drive device 7 is operated according to the sequence described above. In other words, the machining tool 9 is always lowered by the linear motor 15 to the metal sheet 5 to be machined for the time being. Then, an additional pressing force is introduced by the spindle drive 21 only when necessary.

  However, for example, with respect to the thickness of the metal sheet 5 to be processed, it is clear without doubt that the pressing force that can be formed by the linear motor 15 is insufficient to process the metal sheet 5 already in the previous region. In some cases, the thick metal sheet control mode can be adjusted. In the thick metal sheet control mode, the spindle drive 21 is moved together from the beginning. Thus, time loss caused by the connecting stroke is avoided.

  FIG. 6 shows another alternative configuration of the press drive device 40. As illustrated in FIG. 6, in this case, the press drive 40 occupies its starting position before the working stroke. The tool holding portion 41 is provided on a plunger 42 that extends along the work stroke axis 10. The plunger 42, together with the tool holding portion 41 and the processing tool 43 (tool), can be rotated and adjusted around the work stroke axis 10 by a rotation motor 44 forming a rotation drive unit. For this purpose, the rotary motor 44 has an annular rotor 45 which is coupled to the plunger 42 in a gearless manner. The rotor 45 is arranged inside a frame-fixed stator 46.

  In order to generate a pressing force and to generate a stroke movement of the tool holder 41 along the working stroke axis 10, two electric spindle driving devices 47 and 48 work. The first spindle driving device 47 has a stator 49 supported by the machine frame 2, and an annular rotor 50 is provided inside the stator 49. The rotor 50 is directly coupled to a drive nut 51, and the drive nut 51 is engaged with a drive spindle 52. The spindle axis of the drive spindle 52 coincides with the work stroke axis 10. The drive spindle 52 is provided with a pressure disk 53 on the tool holding portion 41 side, and this pressure disk 53 is coupled to the drive spindle 52 via a thrust bearing 54.

  The second spindle driving device 48 is disposed in an axially attached portion provided on the driving spindle 52. The second spindle drive 48 has a higher dynamic characteristic than the first spindle drive 47, but can only generate a relatively low force. The second spindle driving device 48 has a stator 55, and this stator 55 is supported on the driving spindle 52 of the first spindle driving device 47. Further, the second spindle driving device 48 includes a rotor 56 that extends in an annular shape around the work stroke axis 10. The rotor 56 is coupled to the drive nut 57 in a gearless manner. The drive nut 57 is engaged with the drive spindle 58. The spindle axis of the drive spindle 58 also coincides with the work stroke axis 10.

  The drive spindle 58 is coupled to the plunger 42 via a disc spring 59 and an axial rotation bearing 60. The disc spring 59 is preloaded or preloaded in the stroke direction 11 with a spring force that is slightly less than the axial force that can be provided to the maximum of the second spindle drive 48. Overall, an assembly having an overlapping structure in which the two spindle driving devices 47 and 48 are arranged in an overlapping manner is obtained.

  The axial rotation bearing 60 or the disc spring 59 forms a first pressure element. The first pressure element loads the end of the plunger 42 disposed in the axial accommodating portion 61 provided on the drive spindle 52. The pressure disk 53 forms a second pressure element.

  Below, with reference to FIGS. 7-9, the work format of the press drive device 40 is demonstrated. 7, 8 and 9 show the axial speed (dashed line) of the drive spindle 52 relative to the machine frame 2 and relative to the drive spindle 52 during the course of various exemplary workpiece machining. The axial speed (dashed line) of a typical drive spindle 58 is shown.

In the workpiece machining shown in FIG. 7, the machining tool 43 is lowered only by the highly dynamic second spindle drive 48 at the start. At time t ₁ , the drive spindle 58 and simultaneously the machining tool 43 reach a constant speed v ₁ . At time t _2, the machining tool 43 abuts the metal sheet 5 to be processed. In this case, the processing tool 43 loads the metal sheet 5 by the pressing force provided by the second spindle driving device 48. This pressing force is transmitted from the driving spindle 58 of the second spindle driving device 48 to the plunger 42 via the disc spring 59 and the rotary bearing 60.

  In the example shown in FIG. 7, the axial force generated by the second spindle driving device 48 exceeds the spring force that preloads the disc spring 59. However, since the pressing force applied to the processing tool 43 is insufficient for further lowering the processing tool 43 mounted on the metal sheet 5 to deform the metal sheet 5, the plunger 42 has a tool holding portion. 41 and the processing tool 43 supported by the tool holding portion 41 remain stopped for a short time. Therefore, when the drive spindle 58 continues to move downward, the disc spring 59 is pressed together.

As already explained with respect to the first configuration of the press drive 7, the numerical control unit 13 introduces an additional pressing force, for example by measuring the current required by the second spindle drive 48. Therefore, it is detected that the first spindle driving device 47 must be connected. Immediately, i.e. at approximately the time t _2, the control unit 13 of the numerical expression releases the connection stroke. In this connection stroke, the drive spindle 52 is lowered together with the pressure disk 53 in the stroke direction 11. By means of the drive spindle 52, the first spindle drive 47 is also moved in the stroke direction 11 towards the stationary plunger 42 (as usual). Thereby, the disc spring 59 is further compressed. At the same time, however, the downward movement of the drive spindle 58 of the second spindle drive 48 is braked, so that the drive spindle 58 eventually stops relative to the drive spindle 52 (time point t ₃ ). Subsequently, the drive spindle 58 is moved relative to the drive spindle 52 in the return stroke direction 12 by the second spindle drive 48, so that the drive spindle 58 is moved relative to the drive spindle 52 shown in FIG. Occupies the starting position (time t ₄ ).

The stroke length of the connecting stroke is sufficient to allow the first spindle drive 47 to accelerate to the speed at which subsequent workpiece machining takes place (press speed v _p ) during the connecting stroke.

The connection stroke is ended when the pressure disk 53 comes into contact with the plunger 42 in the stroke direction 11 (time point t ₅ ). The pressure disk 53 and the plunger 42 cannot approach further along the working stroke axis 10. Accordingly, the relative mobility between the pressure disk 53 and the plunger 42 in one direction along the work stroke axis 10 and thus the tool holder 41 is eliminated. Next, the first spindle driving device 47 introduces an additional pressing force directly to the plunger 42 and thus to the tool holding portion 41 via the driving spindle 52 and the pressure disk 53.

After the end of the working stroke (time t ₆ ), the drive spindle 52 is lifted in the return stroke direction 12. As a result, the second spindle driving device 48 supported by the driving spindle 52 is also moved in the return stroke direction 12 together with the plunger 42. Backward stroke is terminated at time t _7. The press drive device 40 is again in the operating state shown in FIG.

FIG. 8 shows the speed distribution of both drive spindles 52, 58 during the second exemplary workpiece machining. In the illustrated case, the first spindle drive 47 serves to extend the working stroke of the machining tool 43 formed by the highly dynamic second spindle drive 48. For cost reasons or in order to obtain as high a dynamic drive as possible, the stroke of the machining tool 43 that can be formed by the second spindle drive 48 is relatively short, for example 5 mm. In the case shown in FIG. 8, the stroke of the highly dynamic second spindle drive 48 is not sufficient, so that the first spindle drive 47 must additionally be activated (time point t ₈ ). The stroke of the processing tool 43 is extended. This is because the movement distances of both spindle driving devices 47 and 48 are added together. Backward stroke at least in part, may be performed by moving both the spindle drive 47, 48 at the same time (time _t 9 _~t 10).

  In the case of the workpiece machining shown in FIGS. 7 and 8, the press driving device 40 is operated in the standard mode. In contrast to this, the press drive device 40 can also be operated in a high dynamic mode. FIG. 9 depicts the speed of the drive spindles 52, 58 during the course of an exemplary workpiece machining in the high dynamic mode. Further, in FIG. 9, the speed of the generated processing tool 43 is drawn (solid line). Furthermore, for comparison reasons, the machining tool 43 was generated when the stroke of approximately the same length was performed using only the first spindle drive 47 that is low dynamic, that is, low dynamic. The speed of the processing tool 43 is partially drawn (x line).

  In the high dynamic mode, both spindle driving devices 47 and 48 are operated by the numerical control unit 13 so that both spindle driving devices 47 and 48 are simultaneously accelerated or braked when the machining tool 43 is accelerated and braked. . Thus, the fact that the accelerations of both spindle driving devices 47 and 48 are added together to produce the overall acceleration of the processing tool 43 based on the arrangement of the overlapping structures of both spindle driving devices 47 and 48 is utilized.

Therefore, as shown in FIG. 9, the highly dynamic second spindle drive 48 is used particularly in the acceleration and braking processes. In particular, the second spindle drive 48 remains stationary during the working and return strokes rather on a short time (time from t ₁₁ to t ₁₂ and time from time t ₁₃ to t ₁₄ ). In the case of the workpiece machining shown in FIG. 9, the necessary pressing force does not exceed the preload force or preload force applied to the disc spring 59. At time t _15, the press driving device 40 is positioned in its starting position again.

If a partial velocity distribution (FIG. 9, x-line) of the machining tool 43 when machining is performed using only the first spindle driving device 47 of the lower speed, the high dynamic mode is obtained. The time profit based on the is particularly clear. Whereas backward stroke movement at time t ₁₅ due to the high dynamic mode has already been completed, in the case of using only the first spindle drive 47, finally certain backward stroke machining tool 43 at this time It has just been accelerated to speed.

  On the numerical control unit 13 side, for example, by setting the same target position or the same target speed of the machining tool 43 during the workpiece machining in both spindle driving devices 47 and 48, the high dynamic mode is obtained. It is done. In this case, both spindle driving devices 47 and 48 follow target value settings having different amplification factors. Furthermore, the target value setting is performed under the precondition that it is not necessary to move the machining tool 43 faster than the maximum possible speed of the low-speed first spindle drive device 47.

  Apart from the means for introducing the additional pressing force as required, only by the arrangement of the overlapping structure of both spindle drives 47, 48 and the means for operating both spindle drives 47, 48 in a high dynamic mode, Excellent dynamic drive characteristics provide an advantageous press drive.

  By the way, a highly dynamic press drive device can be obtained in the same manner even when another drive device structure is used. What is decisive is that a first drive device for driving the actuating member in the stroke direction is provided, and a second drive device is driven to drive the plunger or the tool holder in the same stroke direction. It is only that the drive is supported. In addition, control means must be provided that enable the operation of the press drive in a highly dynamic mode in which working strokes are formed by accelerating and / or braking both drives simultaneously.

  In the press drive device 40, in addition to the connection possibility of the first spindle drive device 47 in the high dynamic mode, there is an additional advantage that the connection stroke does not have to be released by the numerical control unit 13. . On the contrary, the connecting stroke is automatic. In the high dynamic mode, the drive spindle 52 is moved together with the pressure disk 53 in the stroke direction 11 during the entire working stroke. When the processing tool 43 comes into contact with the metal sheet 5 by a pressing force exceeding the spring force of the disc spring 59, the disc spring 59 is elastically contracted. The machining tool 43 remains stopped together with the plunger 42 for a short time. However, since the drive spindle 52 is already moved in the stroke direction 11, the drive spindle 52 immediately approaches the stopped plunger 42 in the stroke direction 11 together with the pressure disk 53, so that the pressure disk 53 moves to the plunger 42. Contact. Therefore, a connection stroke is generated.

  The spring contraction stroke when the spring-supported plunger 42 enters relative to the drive spindle 52 can be measured, for example, by a measuring device. In order to move the working tool 43 to a precise position along the working stroke axis 10, the spring contraction stroke currently measured on the control side is taken into account.

Claims (12)

Tool holding in which the workpiece (5) is loaded for machining the workpiece by the tool (9, 43) supported on the tool holding portion (8, 41) provided on the plunger ( 14, 42). A press drive device of a machine tool for generating a working stroke of the section (8, 41), comprising a press drive section and a first pressure element (19, 60), wherein the first pressure element (19, 60) is provided . by pressure elements (19,60) to load the plunger (14, 42), the tool holder by the first pressure element (19,60) is (8,41), a first of the press drive portion It adapted to be loaded by the press force provided by the drive unit (15,48) is provided with a further second pressure element (39 and 53), the second By pressure elements (39 and 53) to load the plunger (14, 42), the tool holder by pressure elements of the second (39 and 53) is (8,41), the press driving unit the second When it is loaded by the additional pressing force provided by the drive unit (21, 47) and only the first pressure element (19, 60) loads the tool holder (8, 41). In the press drive device in which the tool holding portion (8, 41) and the second pressure element (39, 53) are relatively movable, the tool holding portion (8, 41) is the first pressure element ( if it is loaded only by 19,60), if necessary, that the tool holding portion by the first pressure element (19,60) (8,41) Press force when the load is desired to be insufficient to implement the workpiece machining, the relative movability of the tool holding portion (8,41) and the second pressure element (39 and 53) By obstructing , the tool holding portion (8, 41) is loaded with an additional pressing force by the second pressure element (39, 53), and the plunger ( 14, 42 ) is connected to the press driving portion. Is disposed at least partially in an axial accommodating portion (34, 61) provided in the drive spindle (22, 52) of the spindle drive device provided as the second drive unit (21, 47). A machine tool press drive device.   The second pressure element (39, 53) and the tool holding portion (8, 41) are relatively movable along the work stroke axis (10), and along the work stroke axis (10), The press drive device according to claim 1, wherein the working stroke of the tool holding part (8, 41) can be formed by the press drive device (7, 40). By preventing the relative movability of the tool holding portion (8, 41) and the second pressure element (39, 53) in only one direction, the tool holding portion (8, 41) can move the second pressure element ( 39. The press drive device according to claim 1 or 2, wherein the press drive device is loaded with an additional pressing force according to 39, 53). The relative movement between the tool holding part (8, 41) and the second pressure element (39, 53) is indicated by the relative movement between the tool holding part (8, 41) and the second pressure element (39, 53). 4. The blocking device according to claim 1, wherein the tool-holding part (8, 41) is loaded with an additional pressing force by the second pressure element (39, 53) by obstruction by the connecting stroke performed. The press drive device of any one of Claims. Relative movability between the tool holding portion (8, 41) and the second pressure element (39, 53) is determined by the contact surface (37) provided on the second pressure element (39, 53) and the tool holding. The introduction surface (38) provided on the side of the part (8, 41) is obstructed by the connection stroke pressed against each other along the work stroke axis (10) , that is, is eliminated, thereby eliminating the tool holding part (8, 41). The press drive device according to any one of claims 1 to 4, wherein the second pressure element (39, 53) is loaded with an additional pressing force.   The tool holder (8, 41) and the first pressure element (19, 60) are fixedly connected to each other along the working stroke axis (10). The press drive device described. At least one drive unit (21, 47, 48) is configured as an electrical spindle drive and / or at least one drive unit (15) is configured as an inductive linear drive. The press drive device according to any one of claims 1 to 6 . Drive unit corresponding to the first pressure element (19,60) (15,48) is configured as a linear drive electrical spindle drive or induction, any of claims 1 to 7 The press drive device according to claim 1. The plunger (14) has a section projecting in the axial direction with respect to the drive spindle (22) at the end opposite to the tool holding section (8) , in which the plunger (14) is adapted to be loaded by a pressure element (19), the press driving device according to any one of claims 1 to 8. The plunger (14, 42) is loaded by the pressure element (39, 60) in the section arranged in the axial housing (34, 61) provided on the drive spindle (22, 52). going on, press drive device according to any one of claims 1 to 9. A rotation drive unit (21, 44) is provided, and the rotation of the tool holder (8, 41) can be adjusted around the work stroke axis (10) by the rotation drive unit (21, 44). The press drive device according to any one of claims 1 to 10 . When the detection means (18, 13) is provided and the tool holding part (8, 41) is loaded only by the first pressure element (19, 60), the detection means (18, 13) , it can be determined whether it is necessary to load additional pressing force tool holding portion (8,41) by a second pressure element (39 and 53) is either one of claims 1 to 11 1 The press drive device according to item.

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