EP2113316B1 - Bending device - Google Patents

Description

The invention relates to a bending device for bending a workpiece, with an upper tool and a lower tool, wherein the workpiece between the upper tool and the lower tool can be arranged - Bestückungszustand -, the upper tool and the lower tool are mutually movable until the workpiece from the upper tool and the Lower tool is contacted - Biegeanfangszustand - the upper tool and the lower tool under Kraftbeaufschlagung during the bending process under bending deformation of the workpiece are further approaching -Biegevorgang - until the bent end state of the workpiece adjusts -Biegeendzustand -, wherein the upper tool is rigidly formed and the Lower tool (4) is designed contour variable and the lower tool (4) during the bending process - spaced by the workpiece (2) - increasingly hugs the upper tool (3).

Bending devices of the type in question have long been known and serve to carry out numerous different process variants of the bending forming. During free bending, the upper tool and the lower tool often touch the workpiece to be deformed only at a few contact points or contact lines, the bending takes place substantially in areas of the workpiece that do not experience sufficient support by the lower tool.

When bending the upper die and the lower die are formed as a punch and as corresponding die, wherein the bending of the workpiece - starting from the bending initial state - done by free bending, the workpiece is thus acted upon by the upper tool and lower tool with force and initially in the unsupported areas bending deformed. Only in Biegeendzustand access the upper tool and the lower tool over the entire surface into each other, whereby the workpiece is only now impressed the final shape. Here, in contrast to free bending, the workpiece is given a defined shape by the upper tool and the lower tool in the final bending state, disadvantageously However, that the tooling is relatively high, namely to an upper tool always a precisely corresponding lower tool is required.

In bending processes, which in contrast to the previously described method is not based on a straight tool movement, but a rotary tool movement, there is often the problem that when deforming workpieces of low expansion considerable excess lengths must be taken into account so that the workpiece can be subjected to the bending process. In roll bending, the workpiece to be formed is deformed between at least three bending rollers, wherein the upper tool is formed by a roller and the lower tool is formed by the other two rollers, wherein the first roller in immersed the space between the other two rollers with increasing degree of deformation and the desired degree of deformation.

From the French patent application FR-A-2 154 360 It is also known to use an elastic pad as a lower tool in a bending device. The cushion has a substantially rectangular cross-section and consists of an elastomer, such as polyurethane. Inside, the cross section has a round or elliptical recess. The workpiece to be bent is placed on the lower tool and pressed in the bending process by the rigid upper tool in the elastic pad. The workpiece assumes the contour of the upper tool. The disadvantage here, however, that the recoverable forming forces are significantly dependent on the elasticity of the pad, which is not influenced during the bending process.

Object of the present invention is to avoid the disadvantages shown in known bending devices - at least partially - in particular to provide a bending device that allows a strictly predetermined by the bending tool workpiece shape in Biegeendzustand at low tooling costs and avoiding excess lengths.

The indicated object is achieved by a bending device with the features of claim 1. In the bending device according to the invention, the lower tool is thus not rigidly configured as in the known punch-die bending devices, but the lower tool has a different contour in the bending initial state than the contour complementary to the upper tool, preferably one that is particularly suitable, the Store workpiece. During the bending operation, that is, as upper tool and lower tool increasingly approach each other, the lower tool gradually takes the complementary shape to the upper tool, which makes it possible in particular to support the workpiece over the entire surface bending operation over a large area - and not only selectively as in known methods , The lower tool is designed so that it takes more and more the complementary shape of the upper tool during the bending process, so with increasing degree of deformation of the workpiece, until ultimately in Biegeendzustand the upper tool and the contour variable lower tool are nestled, spaced by the between the upper tool and the Bottom tool located and final molded workpiece. If the workpiece does not have a uniform thickness, the shape of the lower tool is not an exact "negative copy" of the upper tool even in the bending state; Upper and lower tool are so far nestled as far as each other, as permitted by the two-sided fitting workpiece in the bending state.

In a preferred embodiment of the inventive bending device, the lower tool is designed so that the workpiece during the bending process with its side facing the lower tool consistent with the lower tool rests. This ensures that the workpiece is supported evenly during the bending process and an equally uniform application of force to the workpiece by the lower tool is possible. While the upper tool is limited to the workpiece only in the area of the contact surface which expands more and more during the bending process, the lower tool can apply force to the workpiece over a significantly larger area and shape it uniformly. This is particularly possible when the lower tool is fully applied to the workpiece. If the lower tool is sufficiently contour-variable, it is possible to contact the workpiece as far as possible over the entire surface by the lower tool during the entire bending process, even if the workpiece in turn is contoured in the unprocessed state.

According to the invention, the lower tool is designed as at least one flat belt, which in the present case is to be understood as meaning any elongate, areally configured band structure. This band structure does not necessarily have to be flexible, so it is not necessary to counteract a deflection by means of corresponding restoring forces. Such a flat belt may be a plastic band, may be made of metal or may consist of a composite, wherein an arrangement of chain links is conceivable. The choice of the specific embodiment also depends on which requirements are placed on the surface quality of the final bent workpiece.

The flat belt must ultimately be designed so that the necessary forming forces can be transferred to the workpiece via it. It is advantageous if the flat belt is designed so that it is as little stretchable in the longitudinal direction during the bending operation in order to avoid unnecessary frictional forces between the lower tool and the workpiece when the upper tool dips into the flat belt during the bending operation. If it is mentioned that the upper tool - spaced by the workpiece - in the lower tool or in the flat belt "dips" then it is not so restrictive means that about only the upper tool is moved to the lower tool. Just as well, the lower tool can be moved to the upper tool; Ultimately important is only that the upper tool and lower tool approach each other, regardless of how upper tool and lower tool behave with respect to a reference system. Upper tool and lower tool must also be acted upon with forces or be stored so that appropriate reaction forces can be absorbed to perform the bending process - the forming of the workpiece - can.

To be able to apply the corresponding forming forces, in the invention, the flat belt can be set by means of a clamping arrangement under tension, wherein the clamping arrangement is designed in particular as a tensioning drive. The clamping arrangement not only has the property that it can apply a certain force to the flat belt, resulting in a desired tension in the cross section of the flat belt. Rather, it is necessary due to the bending process and due to the associated with the bending process and necessary deformation of the lower tool in the form of the flat belt, that the clamping device is able to "nachzuliefern" necessary for the contour change of the flat strip length of flat belt. This object can be realized by an actuator, which acts on the ends or one end of the flat band with a force, but at the same time can change the end of the flat band within certain limits of its position.

In this context, an advantageous embodiment of the invention is characterized in that the clamping arrangement is arranged so that the tension of the flat belt in dependence on the immersion path of the upper tool is controllable. The controllability of the tension of the flat belt is adjustable at which degree of deformation which forces are exerted on the workpiece to be formed.

At which time of the bending process or at which immersion depth of the upper tool in the flat belt which forces are advantageously applied by changing the tension of the flat belt on the workpiece depends quite substantially on the contour of the upper tool and of the work to be performed on the workpiece to adapt the workpiece to the different contours of the upper tool. In certain applications, it is advantageous if the tension of the flat belt varies substantially linearly depending on the immersion path of the upper tool, in other applications, a progressive, ie with the immersion path disproportionately increasing increase in the clamping force may prove advantageous. However, it is particularly advantageous if the clamping arrangement is set up so that the tension of the flat belt can be controlled according to an empirically determined or calculated setting pattern as a function of the insertion path of the upper tool, so that no Dependence on a (too) simple law between immersion path and clamping force of the flat belt.

According to a further advantageous embodiment of the invention, the contour variable lower tool in or on a portion of a rigid molded part. This makes it possible - locally limited - to adapt the workpiece not only the substantially convex contour of the upper tool, but it is also - locally limited - possible to embed concave shapes in the workpiece. It has here z. T. proven advantageous when the workpiece is preformed substantially to the rigid mold part, since it is then easier possible that the lower tool rests already in the bending initial state over a large area of the workpiece to be formed.

According to a further advantageous embodiment of the invention, the bending device on a flexible fitting for receiving a workpiece, wherein the flexible fitting prevents tilting of the workpiece during the bending operation. This is particularly advantageous for workpieces that do not have a stable support surface, such as asymmetrically shaped profiles. By using the described molding, it is possible to encapsulate the workpiece in the molding, at least in part, so that the workpiece and the molding as a whole form a body subject to the bending process which stably bears on the tool. The molding is preferably designed to be flexible, so that it is reusable.

The molding prevents tilting of the workpiece during the bending process, wherein the molding together with the workpiece in particular forms a flat support.

Fig. 1

eine schematische Darstellung eines Biegevorgangs mit einer Ausführungsform einen erfindungsgemäßen Biegevorrichtung,

Fig. 2

eine Ausführungsform einer erfindungsgemäßen Biegevorrichtung mit Umlenkrollen zur Führung eines Flachriemens,

Fig. 3

eine Ausführungsform einer erfindungsgemäßen Biegevorrichtung mit schräg angestelltem Flachriemen und Umlenkrollen,

Fig. 4

eine Ausführungsform einer erfindungsgemäßen Biegevorrichtung mit einem starren Formteil auf dem konturveränderlichen Unterwerkzeug,

Fig. 5

eine Frontal- und Seitenansicht einer Ausführungsform einer erfindungsgemäßen Biegevorrichtung in einem Maschinengerüst und

Fig. 6

ein Formstück zur Verwendung mit einer Ausführungsform einer erfindungsgemäßen Biegevorrichtung.

In particular, there are a variety of preferred ways to design and further develop the bending device according to the invention. Reference is made on the one hand to the claims subordinate to claim 1, on the other hand, to the following description of embodiments in conjunction with the drawings. In the drawing show

Fig. 1

a schematic representation of a bending operation with an embodiment of a bending device according to the invention,

Fig. 2

An embodiment of a bending device according to the invention with deflection rollers for guiding a flat belt,

Fig. 3

an embodiment of a bending device according to the invention with angled flat belt and pulleys,

Fig. 4

an embodiment of a bending device according to the invention with a rigid molded part on the contour variable lower tool,

Fig. 5

a front and side view of an embodiment of a bending device according to the invention in a machine frame and

Fig. 6

a fitting for use with an embodiment of a bending device according to the invention.

In the Fig. 1 to 5 In each case, a bending device 1 for bending a workpiece 2 is shown, with an upper tool 3 and a lower tool 4, wherein the workpiece 2 between the upper tool 3 and the lower tool 4 can be arranged, wherein in the Fig. 1 to 3 the workpiece 2 between upper tool 3 and lower tool 4 is shown; the bending device 1 is located with the workpiece 2 between the upper tool 3 and the lower tool 4 in the loading state, as long as the workpiece 2 is not yet acted upon by the upper tool 3 and the lower tool 4 with force ( Fig. 1a . Fig. 2a . Fig. 3a and Fig. 4 ).

The upper tool 3 and the lower tool 4 are freely movable towards each other until the workpiece 2 is contacted by the upper tool 3 and the lower tool 4 until the bending start condition is reached ( Fig. 1b ). Under the application of force, the upper tool 3 and the lower tool 4 can be brought closer to each other during the bending operation, with bending deformation of the workpiece 2 in the lateral areas ( Fig. 1c ). Finally, the final bending state is reached when the bent end state of the workpiece 2 has stopped ( Fig. 1d . Fig. 2b . Fig. 3b ).

In all illustrated embodiments, the upper tool 3 is rigid, as is well known from known bending devices with punch and die. The lower tool 4 is configured variable in profile in all embodiments and is able to increasingly conform to the upper tool 3 during the bending operation, wherein the lower tool 4 is spaced from the upper tool 3 by the workpiece 2. As a result of the configuration of the lower tool 4 that is variable in contour, more uniform force action of the lower tool 4 on the workpiece 2 is possible than if the lower tool 4 were also rigid, since the lower tool 4 makes contact with the slowly deforming workpiece 2 during the bending operation; the force acting on the workpiece 2 is much more uniform overall and more extensive than would be possible with a rigid lower tool and a rigid upper tool.

In the Fig. 1 to 3 It can be seen that the workpiece 2 during the bending process with its lower tool 4 side facing constantly applied to the lower tool 4 and while the entire surface of the lower tool 4 is applied.

The illustrated embodiments is also common that the contour variable lower tool 4 is designed as a flat belt, wherein the flat belt is made in the illustrated embodiments of plastic. The flat belt must be dimensioned so that it can transfer the necessary forming work to adapt the workpiece 2 to the upper tool 3. So that the flat belt can perform the necessary forming work on the workpiece 2, it is by means of a merely in Fig. 5 shown tensioning set 5 under tension, wherein the clamping arrangement 5 in Fig. 5 is designed as a hydraulic tensioning drive. The clamping assembly 5 fulfills the one task to put the flat belt by applying a tensile force F under tension and on the other to support the flat belt yielding, so that the immersed in the flat belt and the workpiece 2 upper tool 3 necessary for the forming immersion can go back. In the Fig. 5 shown bending device 1 has a clamping arrangement 5, which is arranged so that the tension of the flat belt is controllable in dependence on the immersion path of the upper tool 3, in the present case according to an empirically determined adjustment pattern in dependence on the immersion path of the upper tool 3 is controllable. Due to the adjustability of the tension of the flat belt as a function of the immersion path, it is possible differently sized forming forces required -. B. due to different thicknesses of the workpiece 2 - apply.

To realize a particularly good power guidance and a good looping of the upper tool 3 by the contour variable lower tool 2 are in the embodiments in the Fig. 2 and 3 two inner deflection rollers 6a, 6b are provided, wherein the flat belt is guided on the side facing the upper tool 3 side of the deflection rollers 6a, 6b of the deflection rollers 6a, 6b, and wherein the upper tool 3 during the bending operation between the deflection rollers 6a, 6b under deformation of the flat belt - And the workpiece 2 - between the rollers 6a, 6b dips. In addition, two further, outer deflection rollers 7a, 7b are shown which ensure that the tensioning arrangement 5 always has to deploy its force action in one and the same direction, so that the tensioning arrangement 5 does not have to be movably mounted.

In Fig. 5 is indicated that the distance between the deflection rollers 6a, 6b is adjustable, wherein in the illustrated embodiment, the deflection rollers 6a, 6b can be fixed in a grid of 5 cm in the horizontal direction. In other, not shown embodiments, it is possible to adjust the distance of the pulleys during the bending process, so that the achieved at a certain depth of immersion of the upper tool 3 Umschlingungsgrad the upper tool 3 can be influenced by the lower tool 4.

In the Fig. 3a, 3b a bending device 1 is shown, in which the angle between the connecting line passing through the two deflection rollers 6a, 6b or deflection roller pairs 6a, 6b and the trajectory defined by the insertion movement of the upper tool 3 is not a right angle, in the case of the bending device according to FIG Fig. 3 the angle is even adjustable. This has the particular advantage that the contact point occurring in the bending initial state between upper tool 3 and workpiece 2 is adjustable within wide limits and influence can be taken on the course of the bending process. In the case of the bending device 1 according to FIG Fig. 3 the angle is given by an adjustment of the guide roller 6b and the Umlenkrollenpaares 6b, wherein the adjusting device, not shown permits movement of the guide roller 6b in the direction or against the direction of the dipping movement of the upper tool 3.

In the embodiment according to Fig. 5 stops 13a, 13b are provided, over which the in Fig. 5 not shown workpiece is positionable. The stops 13a, 13b are adjustable in the horizontal direction and arranged above the contour variable lower tool 4. In Fig. 5 It can also be seen that the elements of the bending device 1 are arranged overall in a frame 8, wherein the upper tool 3 is supported vertically adjustable by a column 9 with a translational guide.

In Fig. 4 a bending device 1 is shown, with an upper tool 3 and a contour variable lower tool 4, wherein the contour variable lower tool 4 in a small portion has a rigid mold part 10. The molded part 10 corresponds to a counter-mold 11 within the rigid upper tool 3, so that in sections and concave indentations in the workpiece 2 can be introduced.

In Fig. 6 Finally, a fitting 12 for use with one of the in the Fig. 1 to 5 shown bending devices 1, wherein the mold piece 12 prevents tilting of the workpiece 2. In particular, in irregularly shaped workpieces 2 and cavities having profiles there is a problem in that the workpiece 2 warps during the bending process and deformed in an undesirable manner. In order to prevent such unwanted deformation, a flexible fitting 12 is provided for receiving the workpiece 2, which supports the workpiece 2 so that it can yield during the bending operation only in the direction of Biegekraftbeaufschlagung. The molding 12 can fully enclose the workpiece 2, as in Fig. 6a is shown, but it can also be provided only by a support by merely completing the contour of the workpiece 2 to a regular body. In the in the Fig. 6a and 6b illustrated embodiments, the molding 12 forms together with the workpiece 2 a flat support, so that a secure positioning of the workpiece 2 can be ensured together with the fitting 12 on the contour variable lower tool 4.

Claims (13)

1. Bending device for bending a workpiece (2) having an upper tool (3) and a lower tool (4), wherein the workpiece (2) can be arranged between the upper tool (3) and the lower tool (4) - placement state -, the upper tool (3) and the lower tool (4) can be moved toward one another until the workpiece (2) is in contact with the upper tool (3) and the lower tool (4) - initial bending state -, the upper tool (3) and the lower tool (4) can be brought closer together under the application of force during the bending process under bending deformation of the workpiece (2) - bending state -, until the bent, final state of the workpiece (2) has been reached - final bending state -, and wherein the upper tool (3) is rigidly designed, wherein the lower tool (4) is designed with a variable contour and the lower tool (4) increasingly adapts to the upper tool (3) - being spaced apart by the workpiece (2),
   characterized in
   that the lower tool (4) is designed at least as one flat belt and tension can be applied to the flat belt by means of a tensioning device (5).
2. Bending device according to claim 1, characterized in that the lower tool is designed so that the workpiece (2) lies uniformly against the lower tool (4) during the bending process with its side facing the lower tool (4), in particular, lies completely against the lowing tool (4).
3. Bending device according to claim 1 or 2, characterized in that the flat belt consists of a plastic and/or a metal and/or of a composite material.
4. Bending device according to any one of claims 1 to 3, characterized in that the flat belt is designed as a tensioning drive.
5. Bending device according to any one of claims 1 to 4, characterized in that the tensioning device (5) is aligned so that the tension of the flat belt can be adjusted in dependence on the plunging path of the upper tool (3), in particular, can be adjusted essentially linear with the plunging path or progressive with the plunging path or can be adjusted according to an empirically determined or calculated pattern in dependence on the plunging path of the upper tool (3).
6. Bending device according to any one of claims 1 to 5, characterized in that at least two guide rolls (6a, 6b) are provided, the flat belt is led from the guide rolls (6a, 6b) to the side of the guide rolls (6a, 6b) facing the upper tool (3), and the upper tool (3) plunges between the rolls (6a, 6b) during the bending process between the guide rolls (6a, 6b) under tension of the flat belt - and of the workpiece (2).
7. Bending device according to claim 6, characterized in that the distance between the guide rolls (6a, 6b) can be adjusted, in particular can be adjusted during the bending process.
8. Bending device according to claim 6 or 7, characterized in that the angle between the connecting line running through both guide rolls (6a, 6b) and the trajectory defined by the plunging movement of the upper tool (3) can be adjusted, in particular by an adjusting device for at least one guide roll (6b), wherein the adjusting device allows, in particular, a movement of the guide roll (6b) in the direction or, respectively, opposite the direction of the plunging movement of the upper tool (3).
9. Bending device according to any one of claims 1 to 8, characterized in that at least one stop (13a, 13b) is provided for positioning the workpiece (2).
10. Bending device according to any one of claims 1 to 9, characterized in that the contour-variable lower tool (4) has a rigid form piece (10) in or on one section.
11. Bending device according to any one of claims 1 to 10, characterized in that the bending machine has a flexible form piece (12) for accommodating the workpiece (2), that the form piece (12) prevents the workpiece (2) from tipping over during the bending process, wherein the form piece (12), in particular, is designed on the flat belt or can be reversibly connected to the flat belt.
12. Bending device according to claim 11, characterized in that the form piece (12) supports the workpiece (2) so that the workpiece (2) only yields in the direction of application of force during the bending process.
13. Bending device according to claim 11 or 12, characterized in that, together with the workpiece (2), the form piece (12) forms a flat support.

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