EP3028785B1 - Method for bending tubular workpieces attached to a flange and a bending machine for carrying out such a method - Google Patents

Description

The invention relates to a method for bending tubular workpieces, wherein in each case a workpiece which is fastened to a flange, stretched by the chuck of a rotatable collet and bent by means of a movable bending head, wherein the movements of the collet and the bending head of a central Control be controlled. The invention further relates to a device for bending tubular workpieces according to such a method, comprising a machine frame, a relative thereto movable clamping device with a rotatable collet chuck for receiving a chuck for clamping a tubular workpiece, which is provided with a flange, further with a movable relative to a clamped workpiece bending head, and with a control device for controlling the movements of the clamping device and the bending head for performing desired bending operations on the tubular workpiece.

For some fields of technology, it is necessary to bend tubular workpieces that are flanged, such as vehicle stabilizers or certain components in plant construction. In order to carry out the desired bending operations, the flange must be held in the bending machine, for which the collet must be performed with an overlap or with an internal stress. If, however, the tube to be bent is mounted eccentrically on the flange, the collet must be designed so that it receives the flange off-center so that the longitudinal axis of the tube to be bent is again centered to the longitudinal axis of the collet. However, this has the disadvantage that a special embodiment of the collet is required for each eccentricity, wherein the interference circuit of the collet is increased by the eccentricity. In addition, no corrections can be made to the arrangement / eccentricity.

Proceeding from this, the invention aims to provide a method for bending tubular workpieces available, in spite of the eccentric arrangement of the tube on the flange latter can be clamped concentrically to the collet and even in the presence of different eccentricities the need to use each specific matched collets is avoided.

1. a) Der Flansch des Werkstücks wird konzentrisch am Spannfutter eingespannt, wobei die Mittelachse des Werkstücks um einen Abstand exzentrisch zur Drehachse der Spannzange versetzt ist;
2. b) Die bei jeder Verdrehung der Spannzange auftretenden horizontalen und vertikalen Veränderungen der Lage der Mittelachse des Werkstücks werden laufend von der zentralen Steuerung bestimmt;
3. c) Entsprechend diesen horizontalen und vertikalen Lageveränderungen der Mittelachse des Werkstücks bei einer Verdrehung der Spannzange werden von der zentralen Steuerung die Positionen von Biegekopf und/oder Spannzange laufend vertikal und horizontal so verstellt, daß die Relativlage von Biegekopf und Werkstück zueinander stets ungeändert beibehalten wird.

This is achieved in a bending process of the aforementioned type for tubular workpieces on a bending machine by the following method steps:

1. a) The flange of the workpiece is clamped concentrically on the chuck, wherein the central axis of the workpiece is offset by a distance eccentric to the axis of rotation of the collet;
2. b) The horizontal and vertical changes in the position of the center axis of the workpiece occurring with each rotation of the collet are continuously determined by the central controller;
3. c) According to these horizontal and vertical changes in position of the central axis of the workpiece in a rotation of the collet, the positions of the bending head and / or collet are continuously adjusted vertically and horizontally by the central control so that the relative position of the bending head and workpiece is always maintained unchanged.

In the bending method according to the invention, the flange is arranged concentrically in the chuck and thus concentrically in the collet, wherein the central axis of the tubular workpiece is arranged after clamping eccentrically to the axis of rotation of the clamping device. The collet must be carried out for this without encroachment and even with different eccentricities eliminates the need to use each eccentricity specially adapted collet. In this case, the interference circuit of the collet always remains the same, namely relatively small, and it can be easily made corrections to the arrangement with respect to the eccentricity. In addition, it is not necessary to have to adjust the collet used with regard to the execution of an attack.

The occurring due to the eccentric arrangement of the tubular workpiece on the flange during a rotation of the collet horizontal and vertical changes in the position of the central axis of the workpiece are continuously determined upon execution of a rotary movement of the collet from the central control and their sizes and directions according to the vertical and horizontal positions the bending head and / or the collet continuously adjusted. In this case, the caused by the eccentricity of the tubular workpiece at its flange and its centric clamping in the collet at a rotation of the latter positional change of the tubular workpiece via the central control is compensated by the also required to compensate for the change in position of the tubular workpiece changes in the Positions of the bending head and / or the collet be made so that the relative position of the bending head and workpiece to each other in carrying out this triggered by the central control adjustment (s) is always maintained.

For this purpose, the necessary adjustments to compensate for the eccentricity in rotation of the collet via the central control can be carried out in different ways: on the one hand there is the possibility that only the bending head is rotated in rotation of the collet in its position by the upon rotation of the collet occurring horizontal and vertical offset of the central axis of the tubular body relative to the position at the beginning of the rotation is continuously compensated by a respective equal and equal horizontal and vertical compensation movement of the bending head.

In addition, there is also the possibility that via the central control not the position of the bending head, but that of the collet and thus the position of the central axis of the tubular workpiece continuously by a corresponding vertical and horizontal movement of the collet or the entire clamping device (relative to the bending head) is compensated for by the occurring during the rotation of the collet horizontal and vertical offset of the tubular workpiece is compensated by an equal, but executed in the opposite direction vertical and horizontal displacement of the workpiece during the rotation of the collet.

Finally, however, the required positional compensation of the bending head and workpiece can also be carried out by means of the central control by rotating the collet by simultaneous compensation movements of both the bending head and the collet (or the clamping device). This is advantageous if the adjustment paths to be performed for the compensation movements should be particularly small, in which case the vertical and horizontal compensation movements of the bending head to be performed on the one hand and the tubular workpiece via corresponding movements of the collet or the entire clamping device on the other hand in each case in opposite directions Directions. The distribution of the required compensation movements to those for the bending head and those for the collet via the central control is carried out according to a predetermined and stored in this division rule.

The inventive method is applicable to both tubular, as well as rod-shaped workpieces, wherein the term "flange", which is used in the description of the invention, not only a flange, but also another component which on a tubular or rod-shaped Workpiece is attached, with should include.

In an advantageous embodiment of the method according to the invention, the chuck is clamped to the collet so that the central axis of the recorded workpiece is in a predetermined angular position relative to the collet so that when clamping so far always the same output angular position of the workpiece is fixed in the clamping device, which facilitates the detection of the parameters required for the determination of the compensatory movements in the central control for the position of the central axis of the tubular workpiece.

The determination of the horizontal and vertical changes in the position of the central axis of the workpiece in the central control can be made on the basis of different parameters describing the position of the central axis of the workpiece upon rotation of the chuck, wherein the clamping device of the bending machine corresponding detection means for respective detection of these parameters are assigned, whose signals are routed continuously to the central control. A particularly advantageous embodiment of the method according to the invention is, however, the horizontal and vertical changes in the position of the central axis of the workpiece on the one hand from the size of the eccentricity between the central axis of the workpiece and the axis of rotation of the chuck, which can be entered as a predetermined value in the central control , as well as from the rotation angle of the rotation of the collet determined and according to the bending head and / or the collet is moved horizontally and vertically / are.

However, the invention also aims to propose a bending device for tubular workpieces, which is particularly suitable for carrying out the above-described method according to the invention. According to the invention this is achieved by a bending device for tubular workpieces, with a machine frame, a relative thereto movable clamping device with a rotatable collet chuck for receiving a chuck for clamping a tubular workpiece, which is mounted on a flange, further with a relative to a clamped workpiece movable bending head, and with a central control for controlling the movements of the clamping device and the bending head to perform desired bending operations on the tubular workpiece, characterized in that the flange concentrically clamped on the chuck, while the central axis of the workpiece by a predetermined distance from the axis of rotation of the collet eccentric Furthermore, and wherein the control device for the central control is adapted to the occurring at each rotation of the collet horizontal and vertical changes in the position of the Center axis of a clamped workpiece to determine continuously and in response to these the layers of bending head and / or workpiece respectively vertically and horizontally running so that the position of the bending head relative to the central axis of the workpiece is always maintained unchanged.

In this case, the flange to be clamped in the clamping device, to which the workpiece is fastened, may be formed in a wide variety of forms, but preferably has a substantially circular shape or an elliptical or oval shape.

Advantageously, the flange is attached to an end portion of the tubular workpiece.

An advantageous embodiment of the bending device according to the invention also consists in that the collet, the chuck and the flange are each provided with a mark or an indexing for aligning the position of the central axis of the workpiece to be clamped relative to the collet during clamping, thereby ensuring that after completed clamping the flange-mounted workpiece in an always the same, predetermined angular position (as the starting position) is arranged relative to the collet.

The advantages achieved in the method according to the invention, which are described above, also apply mutatis mutandis to the bending machine according to the invention. In this case, the structural complexity of the bending machine according to the invention compared to known bending machines, which also allow the clamping of a flange with an eccentrically mounted tubular workpiece, so far comparatively low, as doing the execution of an attack of the collet for clamping the workpiece deleted and equally the use of different collets at different sizes eccentricities of the tubular workpiece on the flange are not required.

Fig. 1

eine perspektivische Prinzipdarstellung einer erfindungsgemäßen Biegevorrichtung;

Fig. 2

eine Perspektivansicht der Spanneinrichtung der Biegevorrichtung aus Fig. 1 mit eingespanntem, an einem Kreisflansch exzentrisch angebrachten Werkstück;

Fig. 3

eine prinzipielle Darstellung der Vorderansicht einer Spannzange mit Spannfutter sowie darin aufgenommenem Flansch mit einem an diesem exzentrisch angebrachten rohrförmigen Werkstück zur Verwendung bei einer Spanneinrichtung nach Fig. 2, und

Fig. 4

eine prinzipielle Darstellung des Ablaufs bei dem erfindungsgemäßen Verfahren in Verbindung mit einer Drehung der Spannzange der Spanneinrichtung, wobei die Stellungen am Anfang und am Ende der Verdrehbewegung gezeigt sind.

The invention will now be explained in more detail by way of example with reference to the drawings in principle. Show it:

Fig. 1

a perspective schematic representation of a bending device according to the invention;

Fig. 2

a perspective view of the tensioning device of the bending device Fig. 1 with clamped, eccentrically mounted on a circular flange workpiece;

Fig. 3

a schematic representation of the front view of a chuck with chuck and therein received flange with a eccentrically mounted on this tubular workpiece for use in a clamping device according to Fig. 2 , and

Fig. 4

a schematic representation of the process in the method according to the invention in conjunction with a rotation of the collet chuck, wherein the positions are shown at the beginning and at the end of the rotational movement.

In the following description of the drawings, the same reference numerals are always used for the same parts in the individual figures.

Fig. 1 shows in a perspective oblique view a bending device 1, as it can be used to carry out a bending process according to the invention.

Fig. 1 is only to show in principle the structure of a bending device 1 according to the invention, wherein the representation of conventional components whose use in such bending devices is known to the expert, but which are not necessary in view of the understanding of the invention has been omitted.

The bending device 1 basically comprises a machine frame 2, to which a clamping device 3 for clamping workpieces 7 to be machined is attached at the top. The clamping device 3 is in the example shown in the longitudinal direction of the machine frame 2 movable, which should be indicated by the arrows A only in principle. Usually, the sliding movement of the clamping device 3 z. B. along (usually) two parallel linear guides, which are mounted on top of the machine frame 2.

The clamping device 3 in this case comprises a collet 4 with a chuck 5, at its axial, a bending head 10 facing front flange 6 is clamped centrally to the chuck 5 and thus to collet 4, to which a tubular workpiece 7 is attached. As Fig. 1 shows, the tubular workpiece 7 is attached to the flange 6, which in turn has a substantially circular shape, in a eccentric to this eccentric position.

The collet 4 is in turn connected to a drive 8, via which it can be driven to pivot in both directions of rotation, which is indicated by the arrow Y. The drive 8 is in turn attached to a movable carriage 9, via which the clamping device 3 in the longitudinal direction of the machine frame 2, namely in the two directions of arrow A , is movable.

On the front side of the machine frame 2, a bending head 10 is mounted, which comprises a rotatable bending mold 11 with a concentric to the axis of rotation pivotable bending arm 12 and an upstream in the feed direction of the workpiece 7 of the bending mold 11 slide rail 14, which on the bending mold 11 opposite longitudinal side of Workpiece 7 during bending against this can be applied.

On the bending arm 12 of the bending head 10, a clamping jaw provided with clamping jaws 13 is mounted so that it in the longitudinal direction of the bending arm 12 radially to the bending mold 11 out (and this back) can be moved. For all adjustment, Zustell-, and rotational movements of the individual parts of the bending head 10 are each suitable drives (in Fig. 1 not shown), as they are commonly used in such bending devices 1 for this purpose and as they are well known to those skilled in the art.

The bending head 10 is seated in a suitable manner on a support plate 15 which is provided with vertically extending, parallel linear guides 16, along which the bending head 10 vertically relative to the support plate 15 in the direction of arrow B via a suitable (in Fig. 1 not shown) drive can be moved.

The support plate 15 is in turn attached to a second support plate 17 which has horizontally and transversely to the feed direction of the workpiece 7 extending linear guides 18, along which the holding plate 15 can be moved in the direction of arrow C relative to the machine frame 2.

The second support plate 17 is rigidly attached to the front side of the machine frame 2.

The arrangement shown makes it possible to move the bending head 10 both vertically and horizontally with respect to the machine frame 2 and with respect to the longitudinal axis of the workpiece 7 in a perpendicular to the latter transverse plane.

In the in Fig. 1 illustrated embodiment of the bending device 1, the clamping device 3 on the machine frame 2 only in the longitudinal direction (arrows A ) movable. However, the clamping device 3 could also be mounted on the machine frame 2 so that they can be moved in addition to their longitudinal displaceability in the direction of arrow A also perpendicular thereto in the horizontal direction according to the arrows D and also in the perpendicular thereto extending vertical is adjustable, like this in Fig. 1 is indicated by the arrows E drawn there.

The presentation of the guides and corresponding drives which can be used for such movements in these further traversing directions D and E has been described in US Pat Fig. 1 omitted, since these are measures that are known to any person skilled in bending devices and from him due to his expertise readily feasible.

All traversing, advancing and pivoting and rotating movements that are to be carried out for the proper operation of such a bending device 1, are usually via a central machine control 30, the in Fig. 1 only indicated in principle, controlled according to all required and desired movement sequences. This will be in Fig. 1 only completely schematically indicated by dashed lines signal waveforms between the central controller 30 and the individual to be moved machine parts or motors to be activated.

In Fig. 2 is a perspective view of a portion of the tensioning device 3 of the bending device 1 of Fig. 1 (seen from the front) with a clamped circular flange 6 and an eccentrically mounted on this workpiece 7, wherein in Fig. 2 the representation of the movable carriage 9 is omitted.

The in Fig. 2 shown section of the clamping device 3 illustrates how the circular flange 6 is concentrically clamped on the chuck 5 of the collet 4 and eccentrically carries the workpiece 7.

The central axes of the circular flange 6, this exciting chuck 5 and the associated collet 4 are concentric with each other and thus each other, while the longitudinal center line of the workpiece 7 on the flange 6 on the other hand eccentrically offset by a distance e radially.

As Fig. 2 also shows, the housing of the drive 8 is provided with a radially projecting protruding mounting flange 19, the z. B. screws, on the facing front of the movable carriage 8 can be fastened.

The Fig. 3 represents in a very basic way, a view from the front of the collet 4 with it recorded chuck 5 and this clamped circular flange 6, on which a workpiece 7 is fixed, is shown, wherein Fig. 3 No further constructional details are shown, since they only in quite a fundamental way the structural assignments when clamping a workpiece 7, which sits eccentrically on a circular flange 6 is to show. Accordingly, the clamping and fastening devices, which serve to clamp or attach constructive parts together and are known to those skilled in such clamping devices, not shown.

How out Fig. 3 can be seen, the collet 4, the chuck 5 and the circular flange 6, which is clamped on the chuck 5, arranged concentrically to each other, where M indicates the position of the center axes of collet 4, chuck 5 and circular flange 6.

The flange 6, eccentrically offset by a distance e to the central axis M , a circular cross-section workpiece 7 in a suitable manner, for example, welded.

The longitudinal center axis m of the workpiece 7 is on the flange 6 in the position shown the same relative to the chuck 5 by an angle α to the in Fig. 3 Vertically drawn diameter axis d offset, as in Fig. 3 is shown in detail, in which respect the drawing is expressly referred to here.

In addition, markings 22 or indexings (eg index bores) are mounted on the collet chuck 4, the chuck 5 and the flange 6 in order to always set a same starting position of the workpiece 7 relative to the collet chuck 4 and the chuck 5 during clamping.

If now at the in Fig. 3 shown arrangement, the collet 4 is rotated clockwise by an angle β, ie in the direction of the arrow F in Fig. 3 , Also finds a corresponding rotation of the chuck 5 and of this stretched flange 6 to the center axes M instead.

In this case, the workpiece 7 moves from the solid line in Fig. 3 drawn starting position in the direction of rotation of the arrow F to the position in Fig. 3 dash-dotted line is drawn.

During this rotational movement of the collet 4, the central axis m of the workpiece 7 is displaced horizontally by a distance V _{H in} accordance with the selected direction of rotation and vertically by a distance V _V , as shown in FIG Fig. 3 is drawn.

A bending head 10, which is in operative engagement with the workpiece 7 in a previous bending operation, for example, and is located in a certain relative position relative to this workpiece 7 before the start of the rotation of the collet chuck 4, must in turn likewise be offset by the vertical displacement V _H and the vertical displacement V _{V are moved} accordingly in its position, while maintaining its relative position to the workpiece 7 during the twisting movement of the collet 4 continuously changing its own position such that the displacements of the workpiece 7 are also continuously compensated. This is quite fundamentally in the representation of Fig. 4 shown for the beginning and the end position of the twisting movement.

After completion of the rotation then the workpiece 7 is indeed in a same relative position to the bending head 10 as at the beginning of rotation, which is always understood here by "same relative position" that the relative horizontal and vertical assignment of the bending head to the workpiece 7 remains unchanged. Has changed only the rotational position of the workpiece 7 relative to the bending head 10, so that z. B. one in a previous bending process on the workpiece 7, for example, carried out in a horizontal plane bending after execution of the rotation by the chuck 4 no longer in a horizontal, but in a corresponding angular position protrudes from the workpiece 7, as shown in the illustration of the Fig. 1 is shown in principle. However, in the vertical and horizontal direction maintained relative position between the bending head 10 and workpiece 7 thus results in the end position after execution of the twisting movement by the collet 4, the workpiece 7 has a bending head 3 with respect to opposite twist position, as would have occurred if the workpiece 7 would in turn also have been clamped concentrically and would have changed in a accomplished by the collet 4 rotation relative to the bending head against only in its rotational position, while maintaining the position of its central axis m.

In order to carry out the described method for compensation of the position changes of the workpiece 7 occurring during rotation of the collet 4 by corresponding changes in position of the bending head 10, a suitable device for continuously detecting the angle of rotation β is attached to the clamping device 3, such as an incremental rotation angle sensor, such as such The rotatable clamping device 3 must therefore already be provided in order to carry out a predetermined rotation caused by the central control device 30 as part of a bending program.

Now, if a rotation of the collet 4 takes place, the size of the rotation angle β is detected by such a (not shown in the figures) rotation angle sensor continuously and delivered a corresponding signal to the central control device 30. In this, the eccentricity e is stored by, for example, manual input, wherein the control device 30 from the currently supplied detection signals on the instantaneous angular position of the rotational movement of these signals for the current rotational position of the collet 4 valid values for the horizontal and vertical offset V _H. and V _V determines and corresponding control signals to adjusting motors for the vertical and horizontal displacement movement of the bending head 10 (in the example shown in the figures) or (not shown in the figures) to corresponding motors for a vertical and a horizontal adjustment of the position of the clamping device. 3 relative to the bending head 10 or else (also not shown in the figures) to forward such adjusting both for the clamping device 3, as well as for the bending head 10, in the latter case, the horizontal and vertical position of both the clamping device 3 as well as the bending head s 10 according to a provided and stored in this case in the central control device 30 default for dividing the determined horizontal and vertical adjustment movement to corresponding, superimposed horizontal and vertical adjustment movements of the clamping device 3 and the bending head 10 is made.

Claims (7)

1. Method for bending tube-shaped workpieces (7) where in each case a workpiece (7) attached to a flange (6) is clamped by the chuck (5) of a rotatable collet (4) and bent by means of a displaceable bending head (10) according to a specified bending sequence, the movements of the collet (4) and the bending head (10) being controlled by a central controller (30), characterized by the following process steps:

   a) the flange (6) of the workpiece (7) is concentrically clamped on the chuck (5), the central axis (m) of the workpiece (7) being offset by a distance (e) from the rotational axis (M) of the collet (4);

   b) the horizontal and vertical changes (V_H, Vv) in the position of the central axis (m) of the workpiece that occur with each rotation of the collet (4) are measured continuously by the central controller (30);

   c) according to these horizontal and vertical position changes (V_H, V_V), the positions of the bending head (10) and/or collet (4) are continuously shifted vertically and horizontally with each rotation of the collet (4) by the central controller (30) so that the position of the bending head (10) and workpiece (7) relative to each other always remains unaltered.
2. Method according to claim 1, characterized in that the flange (6) is clamped on the chuck (5) so that the central axis (m) of the workpiece (7) lies in a specified position relative to the collet (4).
3. Method according to claims 1 or 2, characterized in that the horizontal and vertical position changes (V_H, V_V) of the central axis (m) of the workpiece (7) are determined in the central controller (30) from the value of the distance (e) between the central axis (m) of the workpiece (7) and the rotational axis (M) of the chuck (5) as well as the rotational angle (a) of the collet (4) and accordingly the bending head (10) and/or the collet (4) is/are displaced horizontally and vertically.
4. Bending device (1) for tube-shaped workpieces (7), particularly for carrying out a procedure according to claim 1, with a machine framework (2), a clamping device (3) displaceable relative to said framework with a rotatable collet (4) for receiving a chuck (5) for clamping a tube-shaped workpiece (7), which is provided with a flange (6), in addition with a bending head (10) displaceable relative to a clamped workpiece (7), and with a control unit (30) to control the movements of the clamping unit (3) and the bending head (10) for carrying out desired bending processes on the tube-shaped workpiece (7), characterized in that the flange (6) can be clamped concentrically on the chuck (4) and thus the central axis (m) of the workpiece (7) is eccentrically offset by a specified distance (e) from the rotational axis (M) of the collet (4), and the control unit (30) being set up so as to continuously determine the horizontal and vertical changes (V_H, V_V) occurring in the position of the central axis (m) of the clamped workpiece (7) with each rotation of the collet (4) and, dependent hereof, to continuously displace the positions of the bending head (10) and/or workpiece (7) vertically and horizontally in each case so that the position of the bending head (10) always remains unaltered relative to the central axis (m) of the workpiece (7).
5. Bending device according to claim 4, characterized in that the flange (6) has a substantially circular, elliptical or oval shape.
6. Bending device according to claim 4 or 5, characterized in that the flange (6) is disposed at one end of the tube-shaped workpiece (7).
7. Bending device according to any of claims 4 to 6, characterized in that the collet (4), chuck (5) and flange (6) are provided with markings (22) to align the position of the central axis (m) of the workpiece (7) relative to the collet (4) during the clamping process.

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