EP3025803B1 - Drive device for a machine tool and machine tool with such a drive device - Google Patents

Description

• mit einer Spindelanordnung, die zwei parallel zueinander verlaufende Antriebsspindeln aufweist, die jeweils um eine Spindelachse drehbar gelagert und die um die jeweilige Spindelachse antreibbar sind sowie
• mit zwei Spindelmuttern, die mittels der Spindelanordnung gleichzeitig mit

The invention relates to a drive device for a machine tool, in particular for a machine tool for sheet metal working,

• with a spindle arrangement, which has two drive spindles running parallel to each other, each of which is rotatably mounted about a spindle axis and which are drivable about the respective spindle axis and
• with two spindle nuts, by means of the spindle assembly at the same time

Longitudinal movements in the longitudinal direction of the drive spindle are movable, wherein the drive spindles each have at one end an effective longitudinal direction of the drive spindles fixed bearing, the same length and in terms of their torsional stiffness and their axial stiffness are identical and
wherein on each of the drive spindles one of the spindle nuts is seated and the spindle nuts by means of the spindle assembly simultaneously with longitudinal movements in the longitudinal direction of the drive spindles are movable by each of the spindle nuts by means of the associated drive spindle is movable with a longitudinal movement.

The invention further relates to a machine tool, in particular for sheet metal processing, with a machining tool and with a drive device of the above type, by means of which the machining tool is movable.

Generic prior art is known from US 2010/0278606 A1 , This document discloses a numerically controlled machine. The machine comprises a cross slide provided for supporting a work spindle with two mutually perpendicular slide units, a headstock movable along a machine bed, and a tool turret also movable along the machine bed. To drive the carriage units of the cross slide spindle drives serve with two drive spindles. The spindle and the tool turret are driven by a common spindle drive, which also includes two drive spindles. The drive spindles of all drive spindle pairs run parallel to one another and without mutual offset in their longitudinal direction. Spindle nuts resting on each other seated in pairs associated drive spindles are arranged in the longitudinal direction of the drive spindles each arranged at the same height.

Further prior art is disclosed in EP 2 527 058 A1 , This document relates to a machine tool in the form of a press for machining workpieces, in particular sheets. A press tool is actuated by means of a wedge gear, comprising two drive-side gear wedges and two tool-side gear wedges. The tool-side gear wedges store the press tool. The drive-side gear wedges are each provided with a spindle nut designed as a spindle drive drive device. The spindle nuts sit on a common drive spindle and each have a drive motor by means of which they can be moved together with the drive-side gear wedges along the drive spindle. Opposing movements that run the drive side gear wedges simultaneously along the drive spindle and thereby relative to the tool side gear wedges, generate due to the interaction of the drive side gear wedges and the tool side gear wedges movements of the press tool in the transverse direction of the drive spindle. If the drive-side gear wedges simultaneously and rectilinearly moved along the drive spindle, take the drive-side gear wedges the tool-side gear wedges and on this the press tool in the direction of movement. In this way, the press tool can be positioned along the drive spindle.

A trouble-free workpiece machining by the press tool and / or a high machining accuracy require a high positioning accuracy of the drive-side gear wedges and thus a high positioning accuracy of serving for moving the drive-side gear wedges drive device.

Starting from the generic prior art, the object of the present invention is to provide a compactly constructed drive device.

This object is achieved according to the invention by the drive device according to claim 1 and by the machine tool according to claim 9.

According to the claim, a spindle drive with two drive spindles is provided as the drive device for a machining tool of a machine tool, on each of which a spindle nut movable in the longitudinal direction of the relevant drive spindle is seated. Both drive spindles are stationary in the longitudinal direction and rotatable about a spindle axis by means of a drive. A fixed bearing at one longitudinal end of each drive spindle assumes its support in the drive spindle longitudinal direction. Due to the rotary drive of the drive spindles which are stationary in the longitudinal direction, no drive motors that move along with the spindle nuts are required to produce the longitudinal movements of the spindle nuts. As a result, only relatively small masses are to be moved during longitudinal movements of the spindle nuts. A significant, caused by inertia of the spindle nuts impairment of the positioning accuracy of the spindle nuts in the longitudinal direction of the drive spindles does not occur.

For optimum synchronization of the longitudinal movements carried out by the two spindle nuts, it is necessary for the two drive spindles to have the most uniform possible drive behavior. This is achieved by the fact that both drive spindles have the same length and are identical in terms of their torsional stiffness as well as their axial rigidity. The torsional rigidity of the drive spindles is decisive for the twisting of the drive spindles during operation. The axial stiffness of the drive spindles determines their change in length under axial load. Axial forces can be exerted on the drive spindles, in particular via the spindle nuts. Both the twist and the change in length of the drive spindles under axial load are proportional to the length of the drive spindles. In the interests of a uniform drive behavior, the drive spindles of the drive device can also be identical in terms of their moment of inertia, ie with respect to the resistance they oppose to a change in their rotational movement state. The moment of inertia of a fully cylindrical drive spindle is determined by its mass and its radius, the radius of a fully cylindrical drive spindle also influences its torsional rigidity (torsional rigidity) and its change in length under axial load (tensile rigidity).

The drive device according to the invention is characterized in that the spindle nuts lie in the transverse direction of the drive spindles at a small distance from each other, even can cover each other in the transverse direction of the drive spindles. This makes it possible to realize a space-saving design of the drive device according to the invention in the transverse direction of the drive spindles.

Particular embodiments of the invention according to the independent claims 1 and 9 emerge from the dependent claims 2 to 8 and 10 to 15.

A uniform drive behavior of the drive spindles for the spindle nuts is also due to the fact that at the beginning of the simultaneous longitudinal movements of the spindle nuts, the distances of the mounted on the spindles spindle nuts of the fixed bearing of the respective associated drive spindle coincide with each other (claim 2).

Ideally, the equidistance of the spindle nuts and the fixed bearings of the drive spindles during the longitudinal movements of the spindle nuts in the longitudinal direction of the drive spindles is maintained. For rectified longitudinal movements of the spindle nuts, the fixed bearing of the drive spindles are arranged on one and the same side of the spindle nuts for this purpose. When the spindle nuts make opposing longitudinal movements along the drive spindles, the initial equidistance of the spindle nuts and the fixed bearing is maintained when the fixed bearings of the drive spindles are on opposite sides of the spindle nuts. In both cases, each comprising a drive spindle and a spindle nut spindle drives the drive device according to the invention must be designed such that the spindle nuts move in their longitudinal movements at an identical speed along the drive spindles.

The maintenance of the existing at the beginning of the simultaneous longitudinal movements of the spindle nuts equidistance of the spindle nuts and the fixed bearing of the spindle nuts driving drive spindles during the simultaneous longitudinal movements of the spindle nuts is not an indispensable feature of the invention. Negligible is a maintenance of the equidistance of the spindle nuts and the fixed bearing of the drive spindles rather in cases where the spindle nuts are adjusted relative to each other in their simultaneous longitudinal movements only over relatively short path lengths.

According to claim 10, the drive device according to the invention is provided on a machine tool, to which cooperate for generating movements of the machining tool, two drive-side wedge gear elements and two tool-side wedge gear elements together. Each of the drive-side wedge gear elements is connected to one of the spindle nuts of the drive device, each of the tool-side wedge gear elements with the machining tool.

A drive device, the spindle nuts in a preferred embodiment of the invention by means of the drive spindles simultaneously and with opposite longitudinal movements are movable (claim 3) is used in the case of a preferred type of machine tool according to the invention, connected to the spindle nuts drive side wedge gear elements in opposite directions and thereby the machining tool on the tool side To drive wedge gear elements in the transverse direction of the drive spindles (claim 11). In a transverse movement generated in this way, the machining tool can in particular perform a power stroke.

A preferred application of the described in claim 4 embodiment of the inventive drive device results from claim 13. The generated by the drive device according to claim 4 according to claim 4 simultaneous and rectified longitudinal movements of the spindle nuts are evidently used in claim 13 to the associated with the spindle nuts drive side wedge gear elements together with the Tool-side wedge gear elements and the associated tool machining tool of the machine tool to move in the longitudinal direction of the drive spindles. Such longitudinal movements of the machining tool can be carried out in particular for its positioning relative to a workpiece to be machined and / or relative to a complementary machining tool.

The space-saving construction of the drive device according to the invention makes use of the machine tool according to the invention according to claim 12. The drive-side wedge gear elements connected to the spindle nuts are spaced from each other at the beginning of their simultaneous longitudinal movements in the longitudinal direction of the drive spindles. As a result, the drive-side wedge gear elements can be moved towards one another from their initial positions with simultaneous counter-rotating longitudinal movements without the drive-side wedge gear elements having to pass each other. This in turn makes it possible to approach the drive-side wedge gear elements in the transverse direction of the drive spindles close to each other and even to arrange with mutual overlap in the transverse direction of the drive spindles. In any case, the dimension of the wedge gear in the transverse direction of the drive spindles is relatively small. With mutual overlap of the drive-side wedge gear elements in the transverse direction of the drive spindles, moreover, it is possible to guide the two drive-side wedge gear elements in their simultaneous movements in the longitudinal direction of the drive spindles on a common longitudinal guide.

A development of the machine tool according to the invention according to claim 12 results from claim 14. In addition to simultaneous opposing longitudinal movements lead the spindle nuts and connected to these drive side wedge gear elements of this invention type also simultaneous and rectified longitudinal movements in the longitudinal direction of the drive spindles. As a result, the drive side wedge gear elements can not only generate movements of the machining tool in the transverse direction of the drive spindles but also also position the entire unit consisting of drive side wedge gear elements, tool side wedge gear elements and machining tool along the drive spindles. In this case, at the beginning of the longitudinal movements, the spindle nut and the drive-side wedge gear element are spaced on the one drive spindle of the spindle nut and the drive-side wedge gear element on the other drive spindle in the longitudinal direction of the drive spindles. As a result, in the simultaneous and rectilinear longitudinal movements, one of the spindle nuts and the drive-side wedge-gear element connected thereto are in hurry Spindle nut and the associated with this drive side wedge gear element in the direction of the simultaneous and rectified longitudinal movements ahead. Thus, regardless of movements in the direction of the fixed bearing in the direction of the simultaneous and rectified longitudinal movements lagging spindle nut and the associated with this wedge gear element up to the fixed bearing of the associated drive spindle and thus can maximize the provided by the associated drive spindle travel is the bearing of the drive spindle of the trailing spindle nut according to the invention provided such, in particular arranged so that it can be passed by the leading spindle nut and / or by the leading drive-side wedge gear element in the direction of simultaneous and rectified longitudinal movements of the drive-side wedge gear elements and the spindle nuts. Additionally or alternatively, it is conceivable according to the invention that the spindle nut and / or the drive-side wedge gear element, which are moved along one of the drive spindles, pass another bearing point, for example a floating bearing, the other drive spindle.

Thus, the leading spindle nut can pass the bearing of the drive spindle of the trailing spindle nut, the drive spindle of the leading spindle nut in the direction of simultaneous and rectified longitudinal movements of the drive side wedge gear elements and the spindle nuts must extend beyond the end to be passed to the fixed bearing drive spindle of the trailing spindle nut. Since the two drive spindles are the same length, they are for this purpose according to the invention offset in their longitudinal direction against each other.

For applications in which the drive spindles of the drive device according to the invention are not directly connected to the motor shafts of the associated drive motors, claim 5 provides a Erfindungsbauart, in which between each of the drive spindles and the associated drive motor, a drive train is provided with at least one drive element, via which the respective drive spindle can be driven by the associated drive motor. So that the drive spindles, regardless of the drive trains show a uniform drive behavior for the spindle nuts are the two drive trains identical at least in terms of their torsional stiffness. A uniform axial stiffness of the drive trains is dispensable when the drive trains are supported towards the drive spindles, for example at the fixed bearings of the drive spindles in the axial direction such that changes in length of the drive trains do not affect the drive behavior of the drive spindles. Against this background, it is provided in a preferred embodiment of the drive device according to claim 5, that the drive trains are each arranged between the fixed bearing of the drive spindles and the associated drive motor.

As a driving element of at least one of the drive trains comes in a further development of the invention in the longitudinal direction of the respective drive spindle extending and rotatably connected with this spindle extension in question (claim 6). Spindle extensions of the type described can be flexibly dimensioned and thus in particular permit a flexible arrangement of the drive spindles and the drive motors provided for their rotary drive relative to each other.

In addition or alternatively come as a drive elements of the drive trains and clutches in question, which are provided on the other hand between the drive motors of the drive spindles on the one hand and the drive spindles. In the interest of a uniform drive behavior of the drive spindles and the couplings are at least structurally identical perform at least in terms of their torsional stiffness.

Are both drive spindles connected via a spindle extension to the associated drive motor, it is recommended that the two spindle extensions at least in terms of their torsional stiffness perform identical (claim 7). A matching torsional rigidity of the two spindle extensions contributes to a uniform drive behavior of the drive spindles connected to the spindle extensions.

A uniform torsional stiffness of the spindle extensions is realized in a further embodiment of the invention in a simple manner that the spindle extensions are the same length either with equal cross section or at different lengths have different sized cross-sections (claim 8).

A drive device according to the invention with a spindle extension between at least one of the drive spindles and the associated drive motor (claim 6) is provided on the machine tool according to the invention according to claim 15. In the case of this invention type, the fixed bearing of the recessed in the direction of the simultaneous and rectified longitudinal movements of the drive-side wedge gear elements and the spindle nuts drive spindle can be passed from the leading in the direction mentioned spindle nut and / or from the leading in the direction mentioned drive-side wedge gear element. According to the invention, the spindle extension provided for the recessed drive spindle ensures that sufficient free space is available between the end of the recessed drive spindle and the associated drive motor for receiving the spindle nut moved past the fixed bearing of the recessed drive spindle and / or for receiving the drive-side wedge-gear element connected to this spindle nut. It is conceivable that also in the direction of the simultaneous and rectified longitudinal movements of the drive-side wedge gear elements and the spindle nuts superior drive spindle is provided with a spindle extension. Under certain circumstances, this can be shorter than the spindle extension of the drive spindle recessed in the mentioned direction. If this is the case, the cross section of the longer spindle extension is dimensioned larger than the cross section of the shorter spindle extension (patent claim 8) to standardize the torsional stiffness of the spindle extensions of different length.

Figur 1

eine Werkzeugmaschine mit einer Antriebsvorrichtung erster Bauart für ein Bearbeitungswerkzeug,

Figur 2

die Antriebsvorrichtung der Werkzeugmaschine gemäß Figur 1 in der Ansicht in Richtung des Pfeils II in Figur 1,

Figur 3

die Werkzeugmaschine gemäß Figur 1 mit einer gegenüber Figur 1 geänderten Position des Bearbeitungswerkzeugs.

The invention will be explained in more detail below with reference to exemplary schematic illustrations. Show it:

FIG. 1

a machine tool with a drive device of the first type for a machining tool,

FIG. 2

the drive device of the machine tool according to FIG. 1 in the view in the direction of the arrow II in FIG. 1 .

FIG. 3

the machine tool according to FIG. 1 with one opposite FIG. 1 changed position of the machining tool.

According to FIG. 1 has a machine tool designed as a punch press 1 an O-shaped machine frame 2 with horizontal frame legs 3, 4 and vertical frame legs 5, 6. The machine frame 2 encloses a frame interior. 7

In the frame interior 7, a punching die 8 is movably guided in the direction of a double arrow 9 on the lower horizontal frame leg 4. At its top, the punching die 8 forms a support for a in the FIGS. 1 and 3 indicated by dashed lines sheet 10. A in the example illustrated circular die opening of the punching die 8 is in FIG. 2 to recognize. By means of a workpiece guide, not shown in the figures, the sheet 10 can be perpendicular to the plane of FIG. 1 be moved or positioned.

For punching processing of the sheet 10 cooperates with the punching die 8 provided as a processing tool punch 11 together. The punch 11 is fixed with its remote from the punching die 8 end in a punch holder 12, which in turn is mounted on a double wedge 13 in the direction of a double arrow 14 rotationally adjustable.

The double wedge 13 is formed by two tool-side gear wedges 15, 16, which are the tool-side wedge gear elements of a wedge gear 17. As a drive-side wedge gear elements, the wedge gear 17 comprises two drive-side gear wedges 18, 19.

The drive-side gear wedge 18 and the tool-side gear wedge 15 are associated with each other and form a first Keilgetriebeelement- or gear wedge pair. A second Keilgetriebeelement- or gear wedge pair includes the drive-side gear wedge 19 and the tool-side gear wedge 16. Der Double wedge 13 with the tool-side gear wedges 15, 16 is suspended from the drive-side gear wedges 18, 19. In this case, the drive-side gear wedge 18 along a line 20 relative to the tool-side gear wedge 15 and the drive-side gear wedge 19 along a line 21 relative to the tool-side gear wedge 16 are movable.

Corresponding movements of the drive-side gear wedges 18, 19 are generated by means of a drive device designed as a spindle drive 22. Details of the spindle drive 22 are in particular in FIG. 2 to recognize.

According to FIG. 2 the spindle drive 22 comprises a first drive spindle 23 and a second drive spindle 24. The first drive spindle 23 and the second drive spindle 24 extend parallel to each other along the upper horizontal frame leg 3 of the machine frame 2. In the view of FIGS. 1 and 3 the second drive spindle 24 is covered by the first drive spindle 23. A first spindle axis 25 of the first drive spindle 23 and a second spindle axis 26 of the second drive spindle 24 (FIG. FIG. 2 ) lie in one and the same horizontal plane.

By means of a first fixed bearing 27 and a first movable bearing 28, the first drive spindle 23 is rotatably mounted on the machine frame 2 about the first spindle axis 25. In a corresponding manner, a second fixed bearing 29 and a second floating bearing 30 rotatably support the second drive spindle 24 about the second spindle axis 26 on the machine frame 2. In the axial direction, the first drive spindle 23 via the first fixed bearing 27 and the second drive spindle 24 via the second fixed bearing 29 supported on the machine frame 2.

The first drive spindle 23 and the second drive spindle 24 are structurally identical, in particular the same length. They have an identical torsional rigidity and an identical axial rigidity as well as an identical mass moment of inertia.

Via a first drive train 31, the first drive spindle 23 is drive-connected to a first drive motor 32. The first drive train 31 comprises a first spindle extension 33 and a first clutch 34. The first spindle extension 33 extends from the end of the first drive spindle 23 the first bearing 27, the first spindle extension 33 is rotatably connected to the first drive spindle 23 and also supported in the longitudinal direction of the first drive spindle 23 on the machine frame 2. The first clutch 34 establishes the connection between the first spindle extension 33 and the motor shaft of the first drive motor 32.

A second drive train 35 between the second fixed bearing 29 and a second drive motor 36 comprises a second spindle extension 37 rotatably connected to the second fixed bearing 24 and supported on the machine frame 2 in the longitudinal direction of the second drive spindle 24 and a second clutch 38, to which a drive connection between the second spindle extension 37 and the motor shaft of the second drive motor 36 is made.

The first drive train 31 and the second drive train 35 have an identical torsional rigidity, wherein the torsional stiffness of the first drive train 31 from the torsional stiffness of the first spindle extension 33 and the first clutch 34 and the torsional stiffness of the second drive train 35 from the torsional stiffness of the second spindle extension 37 and the assemble second clutch 38.

In this case, the first clutch 34 and the second clutch 38 are identical in terms of their torsional rigidity. The same must apply to the first spindle extension 33 and the second spindle extension 37, so that the entire first drive train 31 and the entire second drive train 35 coincide with each other in their torsional stiffnesses.

Due to the length ratios, the longer first spindle extension 33 would have a smaller torsional stiffness than the shorter second spindle extension 37 for identical cross sections. The effect of the difference in length between the first spindle extension 33 and the second spindle extension 37 for the torsional rigidity of the first spindle extension 33 and the second spindle extension 37 Compensate, the second spindle extension 37 has a stepped Cross-section. Only a first part length 39 of the second spindle extension 37 has the same cross section as the first spindle extension 33. A second partial length 40 of the second spindle extension 37 is compared to the first part length 39 of the second spindle extension 37 and thus reduced cross-section compared to the first spindle extension 33.

The first drive motor 32 and the second drive motor 36 may be independently controlled. The direction of rotation of the two drive motors 32, 36 is switchable. For controlling the first drive motor 32 and the second drive motor 36 is a numerical machine control 41, which in FIG. 3 is indicated and controls all the essential functions of the punch press 1.

By means of the first drive spindle 23 driven by the first drive motor 32, a first spindle nut 42 can be moved in the longitudinal direction of the drive spindles 23, 24. Accordingly, a second spindle nut 43, which is seated on the second drive spindle 24, by means of the driven by the second drive motor 36 second drive spindle 24 in the longitudinal direction of the drive spindles 23, 24 movable. The spindle drives formed by the first drive spindle 23 and the first spindle nut 42 on the one hand and the second drive spindle 24 and the second spindle nut 43 on the other hand are of identical construction. In particular, as a result, the first spindle nut 42 and the second spindle nut 43 move at identical rotational speeds of the drive motors 32, 36 over identical path lengths along the first drive spindle 23 and the second drive spindle 24.

The first spindle nut 42 is connected to the drive-side gear wedge 18, the second spindle nut 43 to the drive-side gear wedge 19. As a result, the drive-side gear wedges 18, 19 carry out the longitudinal movements of the spindle nuts 42, 43 in the longitudinal direction of the drive spindles 23, 24. In their longitudinal movements of the drive-side gear wedge 18 with guide shoes 44 and the drive-side gear wedge 19 are guided with guide shoes 45 on guide rails 46, 47 of the machine frame 2, which accordingly form a common guide for the drive-side gear wedges 18, 19 in the longitudinal direction of the drive spindles 23, 24.

In the FIGS. 1 and 2 the punch press is shown in an operating state in which the punch 11 and the punching die 8 are in one of their end positions along the horizontal frame legs 3, 4 of the machine frame 2. The first spindle nut 42 and the second spindle nut 43 are moved on the first drive spindle 23 and on the second drive spindle 24 in positions in which the distance of the first Spindle nut 42 (middle of the first spindle nut 42 in FIG. 2 dash-dotted lines indicated) of the first bearing 27 of the first drive spindle 23 coincides with the distance of the second spindle nut 43 (center of the second spindle nut 43 in FIG FIG. 2 dash-dotted lines indicated) of the second bearing 29 of the second drive spindle 24. In the longitudinal direction of the drive spindles 23, 24, the first spindle nut 42 and the second spindle nut 43 with a distance d are spaced from each other. To the distance d are also the first drive spindle 23 and the second drive spindle 24 and the first fixed bearing 27 and the second fixed bearing 29 in the longitudinal direction of the same length drive spindles 23, 24 offset from each other.

Should starting from the in the FIGS. 1 and 2 shown ratios by means of the punch 11 and the punching die 8 a punching processing of resting on the punching die 8 sheet 10 are performed, the punch 11 is to be lowered along a stroke axis 48 with a working stroke. For this purpose, the first drive spindle 23 and the second drive spindle 24 are driven by means of the first drive motor 32 and the second drive motor 36 with rotational movements about the first spindle axis 25 and the second spindle axis 26. The direction of rotation and the rotational speed of the first drive motor 32 and the first drive spindle 23 and the direction of rotation and the rotational speed of the second drive motor 36 and the second drive spindle 24 are selected such that the first spindle nut 42 and the second spindle nut 43 in the longitudinal direction of the drive spindles 23rd , 24 at the same time and with the same speed while moving in opposite directions to each other. With the longitudinal movements carried out by the first spindle nut 42 and the second spindle nut 43 along the drive spindles 23, 24, corresponding longitudinal movements of the first spindle nut 42 are connected Drive-side gear wedge 18 and connected to the second spindle nut 43 drive-side gear wedge 19 is connected. As a result, the drive-side gear key 18 move along the line 20 relative to the tool-side gear key 15 and the drive-side gear key 19 along the line 21 relative to the tool-side gear key 16. Thus, the punch 11 via the wedge gear 17 from the position according to FIG. 1 along the lifting axis 48 moves down. The punch 11 penetrates the sheet 10 and runs into the die opening of the punching die 8.

Due to the special design of the spindle drive 22, the described lowering movement of the punch 11 is performed as a linear linear movement along the lifting axis 48 and thus without a movement component in the longitudinal direction of the drive spindles 23, 24. This kinematics of the punch 11 is conditioned by the fact that the drive spindles 23, 24 for the spindle nuts 42, 43 and over these also for the drive-side gear wedges 18, 19 show a uniform drive behavior.

The reason for this is on the one hand the fact that at the beginning of the simultaneous longitudinal movements of the spindle nuts 42, 43, the distance between the first spindle nut 42 and the first bearing 27 of the associated first drive spindle 23 and the distance of the second spindle nut 43 of the second fixed bearing 29 of the associated second drive spindle 24 are the same size. In addition, the first drive spindle 23 and the second drive spindle 24 coincide with each other in terms of their torsional stiffness and their axial stiffness and also with respect to their moment of inertia. Finally, the first drive train 31 of the first drive spindle 23 and the second drive train 35 of the second drive spindle 24 have an identical torsional rigidity.

In interaction, all these features of the spindle drive 22 cause the first spindle nut 42 and the second spindle nut 43 to move towards each other during their longitudinal movements over identical path lengths in the longitudinal direction of the drive spindles 23, 24.

Due to the also matching construction of the one hand by the drive-side gear wedge 18 and the tool-side gear wedge 15 and On the other hand, formed by the drive-side gear wedge 19 and the tool side gear wedge 16 gear wedge pairs of the wedge gear 17 the amount of their identical longitudinal movements of the first spindle nut 42 and the second spindle nut 43 along the drive spindles 23, 24 in the same amount lowering movements of the tool side gear wedges 15, 16 implemented. This, in turn, results in a lowering movement of the punch 11, which is connected to the spindle drive 22 via tilting movements and lateral displacement movements.

That in the course of the longitudinal movements of the first spindle nut 42 and the second spindle nut 43 facing each other, the distance of the first spindle nut 42 from the first bearing 27 of the first drive spindle 23 and the distance of the second spindle nut 43 from the second bearing 29 of the second drive spindle 24 more and differ more from each other, has no appreciable effect on the exact straightness of the lowering movement of the punch 11, since the path lengths over which the spindle nuts 42, 43 move in their opposite longitudinal movements, are only relatively short and thus even at the end of the opposite longitudinal movements the first spindle nut 42 and the second spindle nut 43, the distance between the first spindle nut 42 from the first bearing 27 of the first drive spindle 23 from the distance of the second spindle nut 43 from the second bearing 29 of the second drive spindle 24 only slightly different.

After the punching stroke of the punch 11 is along the lifting axis 48 from its lowered position in the position according to FIG. 1 withdrawn. For this purpose, the first spindle nut 42 and the second spindle nut 43 by means of the first drive motor 32 and the first drive spindle 23 and by means of the second drive motor 36 and the second drive spindle 24 with opposite and directed away longitudinal movements in the longitudinal direction of the drive spindles 23, 24 in the Positions according to FIGS. 1 and 2 moved back. The return stroke of the punch 11 is carried out due to the special design of the spindle drive 22 as an exact linear movement along the lifting axis 48. At the end of the return stroke of the punch 11, the punch press 1 is again in the operating state according to the FIGS. 1 and 2 ,

Is now on the sheet 10 to create a punched-out on the opposite side of the machine frame 2, so first the punching die 8 and the wedge gear 17 must be positioned according to the punch 11. The punching die 8 is for this purpose by means of a not shown in detail and also controlled by the numerical control machine 41 positioning drive from the position according to the FIGS. 1 and 2 in the position according to FIG. 3 method. The target position of the punching die 8 is stored in the numerical machine control 41.

Simultaneously with the punching die 8, the wedge gear 17 and the punch 11 are numerically controlled in a target position of the punching die 8 corresponding target position moves by means of the spindle drive 22. To perform this positioning movement, the first drive motor 32 and the first drive spindle 23 and the second drive motor 36 and the second drive spindle 24 are operated such that the first spindle nut 42 and the second spindle nut 43 at the same time and at the same speed and with rectified longitudinal movements of their Starting positions according to Figures 1 and 2 in the longitudinal direction of the drive spindles 23, 24 move to their destination positions.

Due to the special design of the spindle drive 22, the rectified longitudinal movements of the first spindle nut 42 and the second spindle nut 43 are exactly synchronized. The exact synchronization of the rectified longitudinal movements of the first spindle nut 42 and the second spindle nut 43 is of particular importance.

It allows for a precise approach of the target positions by the spindle nuts 42, 43 and thus also by the wedge gear 17 and the punch 11. In addition, the exact synchronization of the rectified longitudinal movements of the first spindle nut 42 and the second spindle nut 43 causes, regardless of the relatively long Traversing the first spindle nut 42 and the second spindle nut 43 are spaced at their target positions with the same distance measure from each other as at the beginning of their rectified longitudinal movements. The first spindle nut 42 and the second spindle nut 43 maintain their initial distance d until the end of their rectified longitudinal movements. As a result, no relative movements of the drive-side gear wedges 18, 19 connected to the spindle nuts 42, 43 with respect to the tool-side gear wedges 15, 16 occur in the rectified longitudinal movements. This in turn means that the double wedge 13 during its positioning movement in FIG. 1 illustrated position along the Hubachse 48 maintains. The punch 11 thus changes in the rectified longitudinal movements of the spindle nuts 42, 43 its position exclusively in the horizontal direction along the drive spindles 23, 24. Finally, due to the exact synchronization of the rectified longitudinal movements of the first spindle nut 42 and the second spindle nut 43, the distance of the first spindle nut 42 of the fixed bearing 27 of the first drive spindle 23 and the distance between the second spindle nut 43 of the fixed bearing 29 of the second drive spindle 24 at the target positions of the spindle nuts 42, 43 the same size, which in turn contributes to the drive spindles 23, 24 in itself the positioning of the wedge gear 17 and the punch 11 following stroke movements of the punch 11 along the lifting axis 48 show a uniform drive behavior.

At the end of the rectified longitudinal movements of the spindle nuts 42, 43 and the associated positioning movement of the wedge gear 17 and the punch 11, the result in FIG. 3 represented conditions.

The first spindle nut 42 and the drive-side gear wedge 18 are still on the left side of the first fixed bearing 27 of the first drive spindle 23. From the first spindle nut 42 and the drive-side gear part 18 was passed the floating bearing 30 of the second drive spindle 24. Due to a corresponding arrangement and constructive Design of the first spindle nut 42, the drive-side gear wedge 18 and the movable bearing 30, the first spindle nut 42 and the drive-side gear wedge 18 can move past the movable bearing 30 without collision.

The second spindle nut 43 and the drive-side gear wedge 19 have in the course of the positioning movement of the wedge gear 17, the first fixed bearing 27 of the first drive spindle 23 in the direction of movement happens. This was due a corresponding arrangement and structural design of the second spindle nut 43 and the drive-side gear wedge 19 and also due to a corresponding arrangement and design of the first fixed bearing 27 of the first drive spindle 23 possible.

Thus, the second spindle nut 43 and the drive-side gear wedge 19 in the longitudinal direction of the drive spindles 23, 24, the positions according to FIG. 3 can move to the right of the first fixed bearing 27 of the first drive spindle 23, a corresponding space must be present. This free space is created by appropriate dimensioning of the first spindle extension 33 of the first drive train 31 provided between the first fixed bearing 27 and the first drive motor 32. The second drive train 35 may, under the given circumstances, be shorter than the first drive train 31.

For this reason, the second spindle extension 37 of the second drive train 35 is shortened with respect to the first spindle extension 33 of the first drive train 31. Thus, regardless of the different lengths of the first spindle extension 33 and the second spindle extension 37, the torsional stiffness of the first spindle extension 33 and the second spindle extension 37 are identical, the diameter reduction described above is provided on the second spindle extension 37.

Have the punching die 8 and the wedge gear 17 with the punch 11, the position according to FIG. 3 achieved, so in the manner described above, the punching processing of the sheet 10 by simultaneous opposite longitudinal movements of the first spindle nut 42 and the second spindle nut 43 in the longitudinal direction of the drive spindles 23, 24 are performed. Since the wedge gear 17 and the punch 11 are positioned exactly in the longitudinal direction of the drive spindles 23, 24, it is ensured that the punch 11 is arranged exactly concentric with the die opening of the punching die 8 and consequently functionally reliable and trouble-free for machining the sheet 10 in the die opening of the Can dive punching die 8.

Claims (15)

1. Drive system for a machine tool (1), in particular for a machine tool (1) for sheet metal machining,

   • having a spindle arrangement which has two drive spindles (23, 24) which extend parallel with each other and each of which is rotatably supported about a spindle axis (25, 26) and which can be driven about the respective spindle axis (25, 26) and

   • having two spindle nuts (42, 43), which can be moved by means of the spindle arrangement simultaneously with longitudinal movements in the longitudinal direction of the drive spindle (23, 24),

   wherein the drive spindles (23, 24) each have at one end a fixed bearing (27, 29) acting in the longitudinal direction of the drive spindles (23, 24), are equally long and structurally identical with regard to their torsional rigidity and their axial rigidity and
   wherein one of the spindle nuts (42, 43) is seated on each of the drive spindles (23, 24), and the spindle nuts (42, 43) can be moved by means of the spindle arrangement simultaneously with longitudinal movements in the longitudinal direction of the drive spindles (23, 24) by each of the spindle nuts (42, 43) being able to be moved by means of the associated drive spindle (23, 24) with a longitudinal movement,
   characterised in that, at the start of the simultaneous longitudinal movements, the spindle nuts (42, 43) are spaced apart from each other by a distance value (d), different from zero, in the longitudinal direction of the drive spindles (23, 24), and in that the drive spindles (23, 24) are offset relative to each other, in their longitudinal direction, by the distance value (d) of the spindle nuts (42, 43).
2. Drive system according to claim 1, characterised in that, at the start of the simultaneous longitudinal movements of the spindle nuts (42, 43), the existing spacing in the longitudinal direction of the drive spindles (23, 24), between one spindle nut (42, 43) and the fixed bearing (27, 29) of the associated drive spindle (23, 24) corresponds to the existing spacing in the longitudinal direction of the drive spindles (23, 24) between the other spindle nut (42, 43) and the fixed bearing (27, 29) of the associated drive spindle (23, 24).
3. Drive system according to either of the preceding claims, characterised in that the spindle nuts (42, 43) can be moved by means of the drive spindles (23, 24), simultaneously and with opposing longitudinal movements.
4. Drive system according to any one of the preceding claims, characterised in that the spindle nuts (42, 43) can be moved by means of the drive spindles (23, 24), simultaneously and with identically directed longitudinal movements.
5. Drive system according to any one of the preceding claims, characterised

   • in that a drive motor (32, 36) is provided for each of the drive spindles (23, 24),

   • in that a drive train (31, 35) is provided between each of the drive spindles (23, 24) and the associated drive motor (32, 36), the drive train (31, 35) comprising at least one driving element, via which the respective drive spindle (23, 24) can be driven by the associated drive motor (32, 36) and

   • in that the two drive trains (31, 35) are structurally identical, at least with regard to their torsional rigidity.
6. Drive system according to claim 5, characterised in that the drive train (31, 35) of at least one of the drive spindles (23, 24) comprises, as the driving element, a spindle extension (33, 37) which extends in the longitudinal direction of the drive spindle (23, 24) and which is non-rotationally connected to the drive spindle (23, 24) .
7. Drive system according to claim 6, characterised in that the drive trains (31, 35) of both drive spindles (23, 24) comprise a spindle extension (33, 37) as the drive element, and in that both drive trains (31, 35) are structurally identical, at least with regard to their torsional rigidity, by the spindle extensions (31, 35) of both drive spindles (23, 24) being structurally identical, at least with regard to their torsional rigidity.
8. Drive system according to claim 7, characterised in that the spindle extensions (33, 37) of both drive spindles (23, 24) are structurally identical with regard to their torsional rigidity by the spindle extensions being equally long with the same size of cross-section or by the spindle extensions (33, 37) having different lengths and the longer spindle extension (33) having a larger cross-section than the shorter spindle extension (37).
9. Machine tool, in particular for sheet metal machining, having a machining tool (11) and having a drive system (22), by means of which the machining tool (11) can be moved, characterised in that the drive system (22) according to any one of the preceding claims is provided as the drive system (22).
10. Machine tool according to claim 9, characterised

    • in that, between the drive system (22) and the machining tool (11), a wedge gear (17) is provided with two drive-side wedge gear elements (18, 19) and with two tool-side wedge gear elements (15, 16),

    • in that, in each case, a drive-side wedge gear element (18, 19) and a tool-side wedge gear element (15, 16) are associated with each other and form a wedge gear element pair,

    • in that the wedge gear elements (15, 18; 16, 19) of each of the wedge gear element pairs are opposite each other on at least one wedge surface, and the wedge surfaces of both wedge gear element pairs are inclined in opposite directions relative to the spindle axes (25, 26) of the drive spindles (23, 24) of the drive system (22),

    • in that each of the drive-side wedge gear elements (18, 19) is connected to one of the spindle nuts (42, 43) of the drive system (22) and each of the tool-side wedge gear elements (15, 16) is connected to the machining tool (11) and

    • in that the drive-side wedge gear elements (18, 19) can be moved jointly with the spindle nuts (42, 43) by means of the drive spindles (23, 24), simultaneously with longitudinal movements in the longitudinal direction of the drive spindles (23, 24), and thereby a movement of the machining tool (11) can be generated via the tool-side wedge gear elements (15, 16).
11. Machine tool according to claim 9 or claim 10, wherein the drive system (22) is configured according to claim 3, characterised in that the drive-side wedge gear elements (18, 19) can be moved jointly with the spindle nuts (42, 43) by means of the drive spindles (23, 24) simultaneously and with opposing longitudinal movements in the longitudinal direction of the drive spindles (23, 24), wherein the drive-side wedge gear elements (18, 19), during their simultaneous and opposing longitudinal movements move relative to the tool-side wedge gear elements (15, 16) in the longitudinal direction of the drive spindles (23, 24), and thereby a transverse movement of the tool-side wedge gear elements (15, 16) and of the machining tool (11) can be generated in the transverse direction of the drive spindles (23, 24).
12. Machine tool according to claim 11, characterised in that the drive-side wedge gear elements (18, 19) and spindle nuts (42, 43) can be moved towards each other with simultaneous and opposing longitudinal movements in the longitudinal direction of the drive spindles (23, 24), and in that a common guide (46, 47) is provided for the drive-side wedge gear elements (18, 19), by means of which the drive-side wedge gear elements (18, 19) are guided, during their simultaneous longitudinal movements directed towards each other, in the longitudinal direction of the drive spindles (23, 24), wherein, in addition to the spindle nuts (42, 43), the drive-side wedge gear elements (18, 19) are also spaced apart from each other in the longitudinal direction of the drive spindles (23, 24) at the start of their simultaneous longitudinal movements directed towards each other.
13. Machine tool according to any one of claims 10 to 12, wherein the drive system is configured according to claim 4, characterised in that the drive-side wedge gear elements (18, 19) can be moved jointly with the spindle nuts (42, 43) by means of the drive spindles (23, 24), simultaneously and with identically directed longitudinal movements in the longitudinal direction of the drive spindles (23, 24), wherein the drive-side wedge gear elements (18, 19), during their longitudinal movements, carry the tool-side wedge gear elements (15, 16) in the longitudinal direction of the drive spindles (23, 24) and thereby a longitudinal movement of the machining tool (11) can be generated via the tool-side wedge gear elements (15, 16) in the longitudinal direction of the drive spindles (23, 24).
14. Machine tool according to claim 12, characterised

    • in that the drive-side wedge gear elements (18, 19) can be jointly moved with the spindle nuts (42, 43) by means of the drive spindles (23, 24), simultaneously and with identically directed longitudinal movements in the longitudinal direction of the drive spindles (23, 24), wherein the drive-side wedge gear elements (18, 19), during their longitudinal movements, carry the tool-side wedge gear elements (15, 16) in the longitudinal direction of the drive spindles (23, 24) and thereby a longitudinal movement of the machining tool (11) can be generated via the tool-side wedge gear elements (15, 16) in the longitudinal direction of the drive spindles (23, 24) and

    • in that the fixed bearing (27) of the drive spindle (23) which is set back relative to the other drive spindle (24), when viewed in the direction of the simultaneous and identically directed longitudinal movements of the drive-side wedge gear elements (18, 19) and spindle nuts (42, 43), is provided, in particular arranged, in such a manner that, during the simultaneous and identically directed longitudinal movements of the drive-side wedge gear elements (18, 19) and spindle nuts (42, 43), it can be passed by the drive-side wedge gear element (19) and/or by the spindle nut (43) which moves or move ahead in the direction of the simultaneous and identically directed longitudinal movements of the drive-side wedge gear elements (18, 19) and spindle nuts (42, 43).
15. Machine tool according to claim 13, wherein the drive system (22) is configured according to claim 5, characterised in that a spindle extension (33, 37) is provided at least at the drive spindle (23, 24) whose fixed bearing (27, 29) can be passed by the drive-side wedge gear element (18, 19) and/or by the spindle nut (42, 43) which moves or move ahead in the direction of the simultaneous and identically directed longitudinal movements of the drive-side wedge gear elements (18, 19) and spindle nuts (42, 43).

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