DE102010025593A1 - Method and apparatus for the incremental deformation of profile tubes, in particular of profile tubes with varying cross-sections over the longitudinal axis - Google Patents

Abstract

The invention relates to a method for incremental shaping of profile tubes (2), in particular profile tubes (2) with cross sections that vary over the longitudinal axis. In the method according to the invention, a pipe (2) is guided past a tool (3) with the aid of a feed device. The tool (3) can consist of a single or also of several individual tools, the number of these tools (3) depending on the geometry to be produced. Each individual tool (3) has several degrees of freedom in different directions (8) and is also provided with a freely defined geometric surface (6). This means that different tools (3) can also be used, which include tooth shapes (6) or the like, for example. With the simplest tool change in the corresponding device, it is also possible to machine different cross-sections or pipe diameters in a wide range.

Description

The invention relates to a method for the incremental deformation of profile tubes, in particular of profile tubes with varying over the longitudinal axis cross-sections according to the preamble of claim 1 and a device suitable for carrying out the method according to the preamble of claim 25 and correspondingly produced components according to the preamble of claim 34.

Nowadays, profiled tubes for a wide variety of applications are also produced in very different ways. There are currently various process chains available for the production of straight and curved profiles with cross-sections varying over the longitudinal axis and additionally asymmetrical. As a rule, such components are produced in several steps. Combinations of bending processes and hydroforming or the combination of U and O bending are widely used. Furthermore, a process chain of deep drawing of two half-shells and subsequent welding to a hollow profile is used quite frequently. The disadvantage of all currently used process chains is the number of process steps, since this successive execution of individual process steps is very costly. Another cost driver of the currently in use procedures is the relatively high tooling costs. This is accompanied by a low flexibility, since for each geometry to be produced a separate set of tools must be made. Thus, these methods find their applications more in mass production or mass production.

Components with extremely complex contours in mechanical engineering such as gears and screw rotors or other elongated components such as turbine blades are often forged and then precision machined or even braced from the solid. It would be advantageous to produce such structures, for example, from high-strength steel tubes incrementally with high precision forming technology and to reduce the expensive machining finishing to a minimum. Furthermore, these structures, which are often made of solid material, would also be feasible as lighter and resource-saving hollow structures.

Parallel to this, new forming processes have been developed in recent years for flat sheet metal components in which the sheet has the desired final contour in many small forming steps. These forming processes are referred to collectively as "incremental forming processes". This method combines that the forming forces required for use are much lower than with conventional forming processes. The idea of incremental sheet metal forming was already patented in 1967 by Leszak ( U.S. Patent 3,342,051 ), but the necessary tools and CNC controls were not available at the time. It was not until the 1990s that the use of CNC machine tools for incremental sheet metal forming started.

Object of the present invention is therefore to provide a manufacturing method for profile tubes, in particular for profile tubes with varying over the longitudinal axis cross-sections, with the complex pipe sections in a process step and thus can be made much more economical than conventional methods.

The solution of the object according to the invention results with regard to the method from the characterizing features of claim 1 and with respect to the device from the features of claim 25 and with respect to components thus produced from the features of claim 34 each in cooperation with the features of the associated preamble. Further advantageous embodiments of the invention will become apparent from the dependent claims.

The invention relating to the method is based on a method for forming profile tubes, in particular of profile tubes with cross sections varying over the longitudinal axis. Such a method is further developed according to the invention in that a tube with an output profile cross section by means of a feed device at least once past a tool station with at least one tool, wherein the tool and the tube are arranged adjustable in at least one degree of freedom to each other and the Tool locally incrementally converts the pipe cross-section during the relative movement between pipe and tool. The combination of relative feed between the pipe and the tool station and the movement of the tool relative to the pipe can greatly affect the manner of incremental forming of the pipe by the tool. As a result, a large variety of possible forming geometries can be achieved, in particular when providing further relative movements in other spatial directions, such as relative rotations or relative displacements between the tool and the tube, which can be used for the production of correspondingly complex geometries of the formed tube cross sections. Here are the advantages of incremental deformation in terms of only locally acting and therefore forming technology particularly favorable stress of the pipe cross-section combined with the achievable due to the possible relative movements between the tool and tube formed geometries, which previously not economically producible Profile cross-sections in particular of profile tubes with varying over the longitudinal axis dimensions and shapes can be produced economically and accurately. The particular innovation of the method described here is the freedom of design possibilities for any geometric shapes that can be achieved due to the possible relative movements between the tool and the tube. The advantages of such a manufacturing process are the reduced tooling costs and the very high flexibility, which makes this process particularly interesting for prototype construction. Thus, by means of this method a highly economical production of even smaller quantities is possible. As a starting material, it is particularly advantageous to use round or even rectangular pipe material, which can in particular be shaped into helical or polygonal pipe shapes. These can be influenced in particular by the coordinated movement of the various movement devices and only require a relatively small adaptation of the forming tools for adaptation to different tube geometries. Even when using problematic formable materials, the inventive method is also characterized as particularly advantageous. Since this is an incremental process, the deformation limits can be greatly increased compared to the otherwise usual global transformation. When forming z. As of titanium materials together with the high form flexibility, it is close to produce, for example, prostheses and implants with the inventive method. This makes medical technology an interesting field of application. In general, it can be stated that the method according to the invention can be used particularly well for pipes, but basically also for other profiles, such as open or closed profiles. If, in the following, simplistic terms are used for pipes, this is to be understood as meaning always closed pipe profiles, but also other open or closed profile cross sections of substantially prismatic extent. Important here is in particular the relatively thin-walled design of the tube to ensure good formability and a certain ductility of the material of the tube. Due to the material properties, process control can also be used to ensure that individual material properties change during the forming process, eg during the forming process. B. that the strength of the tube is increased by a solidification of the tube material during the forming.

In this case, it is conceivable in a further embodiment that the at least one tool converts the tube cross-section in the longitudinal direction uniformly or in sections non-uniformly incrementally. As a result, in contrast to the usual deformation of pipes to more complex pipe profiles not only over the entire length consistent cross sections are produced, but it is also possible to produce sections just unevenly shaped profile cross sections, such as those needed in automotive technology for the production of body parts , which are to ensure a particularly high energy absorption by deformation in the event of a crash. To produce such crash boxes or crash elements, it is advantageous to arrange stiffer and less rigid profile cross sections together in one component, which can be produced particularly easily in one process step with the method according to the invention. By the corresponding web generation of the webs of the tools, it is also possible to deform a pipe such that the pipe is closed at the end during the forming by the pipe diameter is reduced by the deformation in the end region to zero. It is also possible to separate the deformed tube from the remaining blank when the tool like a turning tool punctures a lathe in the material of the pipe and thus selectively weakens or cuts through the pipe wall.

In an advantageous embodiment, it is conceivable that the at least one tool is moved in up to three translational and / or at least one rotational degree of freedom relative to the tube. As a result of this great freedom of movement of the tool relative to the tube to be reshaped, the most varied geometrical changes of the profile cross section can be achieved due to the incremental deformation, which can be adjusted by the relative movement between the tool and tube by means of a control of these movements. Depending on the geometry of the profile cross section to be produced, it is possible to generate certain geometries of profile cross sections with less than the specified relative movements. For example, to produce a helically curved profile cross-section, a relative longitudinal movement and a relative rotational movement between the tool and the tube are sufficient.

A step-shaped deformation of the tube can be produced in a particularly simple manner by reversing the tube several times past the tool station and in each case locally incrementally reshaping it. As a result, with only a small overall length of a corresponding machine, the entire deformation of the tube into the formed profile cross-section can be divided into a number of individual forming stages, which can be processed distributed to the respective reversing passages at the tool station. Due to the simultaneous free movement between the tool and the pipe, only one tool is normally required to carry out the forming.

An increase in the possible complexity of the deformable profile cross-sections can be achieved if the tube is additionally rotationally rotated, preferably rotationally about its longitudinal axis during the movement past the tool station. Thus, all Umformgeometrien can produce that have a change in the profile cross-section along a helix or whose angular position changes along the length of the tube to be formed. For this purpose, the tube can be rotated by means of a clamping system around its own axis, in order to allow in addition a deformation on the entire circumference of the tube. Thus, load and function adapted structures can be created. The largest producible geometric shape of the deformed profile cross-section can be achieved if the tube during the forming an axial displacement and / or a rotation about its longitudinal axis relative to the tool station performs. The superimposition of this preferably reversing executed linear relative movement between the pipe and tool or tool station with a rotating movement about the longitudinal axis, possibly superimposed with the autonomous positioning of the tool requires a high degree of control technology for coordinated execution, but at the same time allows a simple implementation of Forming with simultaneously high achievable geometry complexity.

In a first embodiment, it is conceivable that the at least one tool has a spherical or spherical machining section which interacts with the tube during the incremental deformation. Such a finger-shaped or shaft-shaped forming tool is basically known from incremental sheet metal forming and can be used particularly well for the successive transformation of complex geometries. In another embodiment, however, it is also conceivable that the at least one tool has at least one machining section adapted at least in sections to the profile cross-section of the pipe to be produced, which interacts with the pipe during the incremental deformation. As a result, the processing speed and the quality of the surfaces to be produced can be improved, in particular in the case of geometrically demanding transformations. In addition, this usually results in larger investment areas between the tool and profile cross-section, which increases the forming zone and thus the processing time is reduced.

In particular, to accelerate the deformation, but also to increase the quality of complex transformations, it is conceivable that several, preferably differently shaped tools in succession, are brought into interactive connection with the tube. Thus, for example, a preforming with a shaft-shaped, the profile geometry to be produced can not be approximated tool, after which the final shaping can be brought to a conclusion with a form-adapted tool. Of course, various intermediate stages and thus corresponding intermediate tools can be used, in particular depending on the geometry to be produced of the formed tube.

An improvement in the accuracy of the deformation of the tube can be achieved if the tube is radially supported in addition to the at least one tool against the forces due to the incremental deformation by a preferably radially attacking support means. If only one tool or a larger number of tools arranged asymmetrically with respect to the tube are used in the incremental tube forming, the primary radial loading of each tool exerts a bending load on the tube relative to the tube as a result of which the tube is possibly unduly deformed. In order to absorb this load, additional support may be provided on the outer circumference of the tube by means of a steady rest or similar device which absorbs the radial forces and thereby reduces the bending load on the tube.

It when the tube is held at the end, preferably at one of its ends in a clamping device is particularly advantageous. As a result, z. B. by a one-sided as in a lathe clamping the tube, the free end of the tube are completely reshaped without having lost on both sides end portions of the tube must be separated.

With regard to the state of stress of the tube during the forming, it is advantageous if the tube is held under its tensile stress during its movement past the tool station, preferably between two clamping devices respectively arranged at the end. In this way, a tensile stress is introduced into the tube during the forming, which overlaps with the local forming stresses and on the one hand leads to a stabilization of the tube against a possible bending load and on the other hand, the local transformation is beneficial.

Since the execution of the relative movements between the tool and the tube is the cause of the accuracy of the forming and thus of the quality of the formed tube, it is advantageous if the relative movements of the tube and at least one tool are coordinated with each other by means of a control. By coordinating all required movements with the aid of NC axes and a central NC control, it is possible to do so achieve high accuracy, also the processing can be prepared computer-assisted and possibly simulated.

In a further embodiment, it is also conceivable that the tube is stabilized during the local incremental deformation in the region of the tube wall by an inner support which is arranged in the interior of the profile cross-section of the tube. Such supports are basically known for example in the profile rolling of tubes and are used for more accurate production of the profile-rolled tubes by a corresponding counter-holder in the region of the forming zone. Can be realized such an inner support by an equally single or multi-axially positionable inner mandrel, which supports the tube from the inside, thus enabling an even higher accuracy of the workpieces. This internal mandrel can, as well as the externally acting forming tools, have different geometries, so also possibly changed or adapted depending on the particular forming stage. By a single or multi-axial relative positioning of such an inner mandrel relative to the inner pipe wall and the outside of the pipe wall attacking tool, the forming zone of the tool can always be supported exactly by the inner mandrel and thus an optimal incremental deformation can be generated. Also, the tube formed between tools and internal mandrel can be additionally calibrated during this deformation.

In another embodiment, however, it is also conceivable that the pipe wall is supported during the local incremental deformation by a preferably foam-like or honeycomb-like support material introduced into the interior of the pipe, which is arranged in the interior of the pipe cross section. Here, no local support of the pipe wall takes place only in the region of the forming zone, but the support takes place substantially over the entire surface. For this purpose, the tube can be filled prior to forming with metal foams or similar foam or honeycomb support structures. The load limit of the Dell or buckling stiffness, which is often problematic in the case of high-strength thin-walled components, can be significantly increased by the inner support effect that can be achieved thereby. In a further embodiment, it is also conceivable that the support material remains after the forming in the interior of the formed tube and thus unfolds for the subsequent use of such formed tubes also has a corresponding supporting and stabilizing effect to increase the rigidity. Also central hub components can be easily connected to such a support material. It is also conceivable that the support material is formed such that the local compression of the support material by the deformation of the tube cross-section causes an additional solidification of the support material. As a result, these foam or honeycomb structures can be compacted locally on the surface, similar to the structural design of animal or human bones is the case, and thereby further stabilization of the tube is achieved during and after forming.

In a further advantageous embodiment, it is conceivable that the at least one tool in addition to the relative movements relative to the tube oscillating performs in at least one spatial direction. By such small-stroke movements, the incremental deformation can be simplified because of the small strokes, which are applied as by oscillating oscillators on the tool, an improved flow behavior of the material of the tube and thus a simplified deformation of the tube can be achieved.

In a further embodiment, it is also conceivable that two tubes inserted into each other at least with associated end regions are formed together in an incremental manner, so that the two tubes are connected to one another in a force-locking or form-fitting manner. The skillful processing of two different tubes in the end region, the production of a positive connection similar to a snap or screw cap is also possible. This is advantageous, for example, in the assembly of profile-like structures and can even make welding processes superfluous, since the transmission of torques is also possible by means of such connections.

Due to the variety of relative movement possibilities between tool and pipe, it is possible that the tube cross-section of the formed tube is formed asymmetrically. As a result, a further broadening of the manufacturable geometries can be achieved, for. B. can such unsymmetrical forms connections z. B. for pipe joints, branches or the like. Are made.

With regard to the geometries that can be produced, it is conceivable that the deformed regions of the tube cross-section form functional surfaces, preferably toothings, connecting elements, guide surfaces or the like. As a result of the reshaping production of such geometries, otherwise elaborate milling processes made of solid material can be replaced by tube forming. As a result, on the one hand, the component weight can be reduced technically, on the other hand, the production is much more cost-effective with constant component properties. For the realization of light compressors, for example for applications in the field of mobile Fuel cell technology, can be made with the inventive method of seamless, high-strength steel pipes extremely lightweight and high-strength compressor. Also, the recently encountered again Roots compressor can be prepared in such a way. Even gears and light worm wheels can be produced in this way.

The invention further relates to a device for incremental deformation of profile tubes, in particular of profile tubes with varying over the longitudinal axis cross sections, in particular for performing the method according to claim 1, wherein the device comprises a clamping device for the incrementally reshaping tube and at least one tool station with at least one tool wherein the clamping device and thus the clamped tube and the tool station are arranged relative to each other displaceable and / or rotatable and a single or each tool in the tool station can perform at least one relative movement relative to the tool station, in which the clamped tube is formed incrementally. The relative displacement between umzuformendem tube and the tool or the tool station can be achieved, for example by an arrangement of the clamping station and the tool station relatively movable to each other on a common, preferably aligned in the longitudinal direction of the tube machine bed, wherein clamping station and tool station individually or both to each other and / or are arranged rotatable. As a result, the basic movement between pipe and tool can be easily generated. As a result of the additional relative movements of the tool or tools relative to the tube and their superimposition with the basic movement explained above, all movement necessary for generating even complex forming geometries can be provided for carrying out the method according to the invention.

In this case, it is also possible in a further embodiment that the clamping device clamps the tube on one side or on both sides end side. With a one-sided tension similar to a lathe, the producible deformed profile length is the largest, but at the same time the bending load is highest. Therefore, it must be ensured in such transformations that the tool attack is as symmetrical as possible and the load on the tube due to the bending loads of the individual tools compensate each other. This can advantageously be achieved by arranging more than one tool at a time in the tool station, preferably symmetrically relative to the pipe, which engage the pipe and at the same time incrementally reform the pipe cross-section in several, mutually separate forming zones. In this way, in addition to the reduction of the forming time by the simultaneous deformation in several forming zones and the total load of the tube can be reduced.

To implement such a parallel deformation of the tube in several deformation zones at the same time it is advantageous if a number of tools in the tool station is received radially and / or axially relatively movable to the tube, in a further embodiment by means of independent drives, the relative movements of the tool relative to run the pipe. As a result, on the one hand, a compact design is achieved in which the tool station can be moved relative to the pipe as a whole on a machine bed, while the individual tools necessary for the incremental deformation depending on the complexity of the geometry of the deformed tube additional movements relative to the tool station and with it to the pipe. In a further embodiment, it is also conceivable that a plurality of tools can be brought into engagement with the pipe by means of a change station, such as by using the change station different shape-adapted tools depending on the progress of the forming of the tube in the tool station and engaged in the manner described be brought with the tube.

To further accelerate the deformation, it is also conceivable that in the tool station a number of tools in the longitudinal direction of the tube staggered relative to the pipe cross-section are arranged adjustable. As a result, several tools work not only in particular symmetrically to the circumference of the tube to be formed simultaneously, but it can be created by the staggered arrangement in the longitudinal direction of the tube distributed multiple simultaneous processing zones. However, this can only be realized if the tube in the area to be machined over the entire length of all such processing station can be passed over and usually requires a correspondingly large overflow of the pipe. In a further embodiment of this procedure, it is advantageous if the processing sections which come into contact with the pipe cross-section of the tools arranged staggered in the longitudinal direction of the pipe are adapted to one another in terms of shape and dimensions and thus complement the simultaneously occurring machining operations during reversing operation of the device. build on each other.

The invention further relates to an incrementally formed profile tube, produced in particular by the method according to claim 1 and / or using the device according to claim X, in which the output profile of the profile tube as a standard hollow profile, preferably round or rectangular, is formed over its longitudinal extent constant cross-section, in particular closed hollow profile. Such prefabricated profile tubes can be prefabricated inexpensively as a rolled section or as a welded profile used for incremental forming. In this case, however, it is also conceivable that the output profile of the tube is formed at least partially preformed adapted to the executed incremental deformation by z. B. larger Umformoperationen the finished tube are already provided in the prefabrication. This will be possible primarily for tube cross-sections, which have constant shape over the entire length.

In a further embodiment, it is conceivable that the deformed tube cross-section has helical shape sections or polygonal cross-sectional sections or rounded cross-sectional sections arranged longitudinally.

It is particularly advantageous that the deformed tube cross-section can have deformed and non-formed sections arranged in the longitudinal extent which can not be produced economically or economically using conventional profiling methods for tubes.

A particularly preferred embodiment of the method according to the invention and of the device according to the invention is shown in the drawing.

Show it:

1a . 1b A first representation of the basic sequence of the method according to the invention for producing a profiled round tube with a molded-in groove by means of incremental deformation, in which 1b the successive forming stages of the incremental forming have been combined into a representation,

2a - 2e A basic representation of a typical machining situation of a pipe transformed into a star-shaped pipe cross-section,

3 A type of stadia diagram of a typical machining sequence of a pipe shaped into a star-shaped pipe cross-section, in which the successive forming stages of the incremental deformation were combined into a representation,

4a - 4c - Schematic representation of a number of procedurally deformed stages of the profile cross-section according to 3 together with the respective tools used in a plan view and a spatial view,

5a - 5i A schematic representation of a number of procedurally deformed profile cross sections in a plan view and a spatial view,

6a - 6b A schematic representation of a number of procedurally deformed profile cross sections in a plan view and a spatial view,

6c Representation of a procedurally deformed tube profile with differently shaped or non-formed sections along the longitudinal extent of the tube,

7a - 7c - Representation of the basic structure of an apparatus for performing the method according to the invention in a three-dimensional view and two planar views with a clamped on both sides of the tube to be formed,

8a - 8c - Representation of the basic structure of an apparatus for performing the method according to the invention according to 7 in a three-dimensional view and two plane views with a pipe clamped on one side,

9a - 9c - Representation of the basic structure of an apparatus for performing the method according to the invention according to 7 in a three-dimensional view and two planar views with a unilaterally clamped tube to be formed and an additional possibility of movement of the tools relative to the embodiment according to 8th .

10 - Schematic representation of a number of used in the procedural forming tool shapes in a plan view and a spatial view.

In the 1 is a first representation of the basic sequence of the method according to the invention for producing a profiled round tube with a molded groove with the aid of the incremental deformation to recognize the basic principle of the method according to the invention is illustrated. As a starting material here is a round tube for the sake of simplicity 2 used in a later described device 12 about a displacement axis with the displacement direction 4 longitudinally displaceable and about an axis of rotation with the direction of rotation 23 is held rotatable. This tube becomes relative to an indicated tool station only 13 moves in which a tool 3 with a sharp-pointed shape section here 6 is held. The tool 3 can be compared to the tool station to linear displacements along the only schematically indicated displacement directions 8th be moved and thus also during the relative movement of the tube 3 relative to the tool station 13 move. It is also conceivable that the tool in addition to the relative displacements in the displacement directions 8th Relative rotation to the tool station 13 executes, but not shown here.

In the in the 1a indicated Umformsituation 1 becomes a superposition of the sliding movement of the pipe 2 along the direction of displacement 4 with a radial feed of the tool 3 superimposed, causing the serrated shape section 6 of the tool towards the center axis of the pipe 2 to move and a groove-like furrow in the profile wall of the tube 3 presses. During the relative displacement of the pipe 2 in the direction of displacement 4 becomes the tool 3 either continuously delivered or between individual strokes of the reversibly formed relative displacement of the tube 2 in the direction of displacement 4 repeatedly delivered piecemeal, so that the mold section 6 pushes deeper into the profile cross section at the next pass. As a result, a locally acting, incremental deformation of the tube 2 towards a shaped profile cross-section 11 causes, depending on the degree of deformation of the tube 2 a number of such reversing strokes required.

To support the pipe 2 towards the predominantly radially on the tube 2 acting forming forces and a resulting bending load of the tube 2 can the pipe 2 by a number of on the outside diameter of the pipe 2 adjacent counterpart 5 be supported, in the delivery direction 9 be moved up to the pipe and partially absorb the forming forces. It is also conceivable that the support is not due to on the outer diameter of the tube 2 adjacent counterpart 5 is supported, but that a thorn-like counterhold in the interior of the pipe 2 is driven into it and there on the inner wall of the pipe 2 supported. This spike-like counter holder can also be controlled in the interior of the tube 2 be retracted that he is essentially always in the field of forming by the tool 3 on the inner wall of the pipe 2 rests and at the same time acts as a counter-tool.

In 1b the successive forming steps of the incremental forming were summarized in a representation, so that there the two stages of delivery of the tool 3 respectively. 3 ' as well as the resulting forming depth of the groove-shaped profile shape 7 can be recognized simultaneously.

In the 2 is in a schematic representation of a typical processing situation of a transformed into a star-shaped pipe cross-section pipe 2 to recognize that by two tools 3 with curved fork-like shaped sections 6 in the star-shaped profile cross-section 11 is transformed. For the sake of simplicity, the symmetry is based on a circular pipe cross-section of the pipe 2 in a carriage 17 displaceable in the direction of displacement 8th to the tools 3 is held. Each of the tools 3 can relative to the pipe 2 again in shift directions 8th be adjusted so that the fork-shaped mold sections 6 the tools 3 precisely to the profile walls of the tube to be formed 2 can be hired. Depending on the set contact point or the contact surface of the fork-shaped mold sections 6 with the pipe wall, the pipe will be during the reversing longitudinal adjustment in the direction of displacement 4 Incremental reshape and thus change the profile cross-section locally. Will now successively such reversing longitudinal adjustments in the direction of displacement 4 each with changed delivery of the tool 3 relative to the tube 2 carried out, the tube is successively converted into the star-shaped profile cross-section. The basic process of incremental sheet metal forming is known and will therefore not be explained in detail here. By providing two simultaneously engaged tools with curved forked shaped sections 6 The bending load of the tube is reduced, since that is a tool 3 almost as a counterpart to the other tool 3 serves. It is of course conceivable that more than two tools 3 simultaneously engage the pipe, with a symmetrical arrangement of the tools relative to the profile cross-section of the pipe 3 are beneficial. Also, the tools can be arranged not only relatively displaceable, but also relatively rotatable to the tube.

In the 3 is a kind of stage plan of a typical machining sequence of a tube transformed into a star-shaped pipe cross-section 2 to recognize, in which the consecutive forming stages of the incremental deformation as already in the 1b were summarized in a presentation. This is from a round tube 2 an approximately triangular star-shaped tube cross section formed with outer rounding, which separates by deeper grooves, the rounded outer parts of the pipe cross-section. In a first, shown on the right most forming stage is during the reversing longitudinal movement in the direction of displacement 4 a tool 3 '' with a projecting mold section 6 used, wherein the projecting mold section 6 the deeper grooves 7 the deformed profile cross-section 11 preforming. Because of the incremental Forming in the interaction between the above mold section 6 and pipe 2 Forming limits are set from the material properties of the pipe material are usually a number of reversing longitudinal movements in the direction of displacement 4 be necessary to the groove 7 form one after another, as with the radially further submitted tool 3 ' is indicated. The ultimate desired geometry of the profile cross-section of the formed tube 11 will then have three tools 3 with fork-like shaped sections 6 made the formed profile 11 surrounded in a linear manner during the last forming pass and produce the dimensionally and formally accurate profile cross section of the formed tube.

In the 4a to 4c are schematic representations of a number of procedurally deformed stages of the profile cross-section according to 3 recognize together with the tools used in a plan view and a spatial view. This makes it even better the successive reshaping of the originally round profile cross-section of the tube 2 towards the formed profile cross-section 11 recognize that in the 3 is shown together.

In the 5a to 6b are schematic representations of a number of procedurally deformed profile cross-sections in a plan view and a spatial view to recognize the basis of which the potential of the method according to the invention with respect to the recoverable Umformgeometrie is recognizable. By superposition of the various relative movements described above, such as relative displacements and relative rotations in the incremental deformation by the tool or tools helically coiled profile cross sections as in 5a , polygonal bounded profile cross sections as in the 5b to 5i be produced with straight and rounded, but also sharp-edged profile sections that would not be produced with other manufacturing processes or not in a single process stage.

In the 6c is an illustration of a procedurally deformed tube profile with differently shaped or unconverted sections along the longitudinal extent of the tube to recognize. In this way, unlike conventional production methods for profiled tubes, it is also possible to achieve longitudinally limited deformations of the profile cross section, which can be used for locally modified deformation properties, for example for the production of deformation structures, for example in crash structures of bodies or the like. For this purpose, either sections of the tube as described above by appropriate tools 3 profiled, and then leaving a reshaped pipe section made another shaped section or the tools are left in engagement along the entire length of the tube, wherein the tube 2 is actually reshaped only in the selected area.

In the 7a to 7c is an illustration of the basic structure of an apparatus for performing the method according to the invention in a three-dimensional view and to recognize two planar views with a clamped on both sides of the tube to be formed. Here, the tube is between two sides on a machine bed 14 with top guides 21 arranged clamping carriage 17 taken on the machine bed 14 by means of drives 15 in adjustment 4 are arranged adjustable. This arrangement is basically reminiscent of the construction of lathes for shafts or the like. The tension slide 17 in turn have a rotary drive 16 for a rotary motion not required here about the longitudinal axis of the tube 3 in the direction of rotation 23 on.

In the middle between the clamping carriages 17 is a whole with the item number 19 designated tool holder on the machine bed 14 and guided by the guides 21 arranged in which the individual tools 3 recorded and by means of only indicated in principle drives 18 in the adjustment directions 8th are held adjustable. This unit of tool holder 19 and tools 3 as well as their drives 18 should be considered as a tool station as a whole 13 be designated.

The tool station is via a drive 15 relatively displaceable between the tension slide 17 at the guides 21 held and can be substantially over the entire length of the tube 2 relative to the tube 2 be moved.

Due to this relative displacement in the direction of displacement 4 along the tube as well as the not exactly to be recognized, but described in detail above adjustment of the tools 3 in the direction of displacement 8th radially on the pipe 2 to become the right recognizable tube 2 from its initial state in a deformed state 11 successively incrementally reshaped. The required movements of the individual drives are controlled 15 . 18 by a numerical control, not shown.

In the 8a to 8c is a modified embodiment of an apparatus for performing the method according to the invention according to 7 in a spatial view as well as two plane views with a cantilevered reshaped tube to detect the pipe 2 only one side is supported in a clamping slide and therefore can be processed freely up to its one end. Otherwise correspond to the structure and the possibilities of movement of the embodiment according to the 7 so that reference may be made thereto.

In the 9a to 9c is a modified embodiment of an apparatus for performing the method according to the invention according to 8th shown in a three-dimensional view and two planar views with a unilaterally clamped reshaped tube, in which an additional possibility of movement of the tools relative to the embodiment according to 8th is provided. Are in the 8th the tools 3 essentially only radially to the tube and thus in the direction of displacement 8th slidably arranged, so is in 9 also a shift transversely to the longitudinal extent of the tube 2 intended. This transverse displacement makes it possible to produce profile cross sections with transverse shapes 22 which can be locally introduced transversely to the longitudinal axis of the tube. Otherwise, the structure and the possibilities of movement correspond to the embodiment according to the 7 respectively. 8th so that reference may be made thereto.

In the 10 Figure 3 is a schematic representation of a number of molds used in the process of forming 3 with mold sections 6 each to be seen in a plan view and a spatial view. These forms of tools 3 consist in the simplest case of a shaft-shaped and provided with a hemispherical end tool according to 10a , as it is also used in the incremental sheet metal forming. Such tools 3 but can also be adapted to the profile cross-section of the formed tube to be produced 11 Have curves, pointed projections or other shape elements, with the reshaped profile cross-section of the tube 2 interact and the profile cross section punctiform or linear in the region of the mold sections 6 transform incrementally. The selection shown represents only a small part of the conceivable designs of such tools 3 and can be varied widely in the context of the present invention.

LIST OF REFERENCE NUMBERS

1

forming region

2

Pipe in the initial state

3

Tool

4

relative longitudinal displacement tube

5

outer counterholder

6

Mold section

7

profile form

8th

relative movement directions tool

9

Anstellrichtung outer counterhold

10

Rotary drive tube

11

formed or partially formed section pipe

12

reshaping

13

tool station

14

machine bed

15

drive

16

Drive clamping slide

17

clamping slide

18

tool drive

19

tool holder

20

Rotary joint

21

guides

22

cross-shaping

23

Direction of rotation pipe

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• US 3342051 [0004]

Claims (40)

Method for shaping profile tubes ( 2 ), in particular of profile tubes ( 2 ) with cross-sections varying over the longitudinal axis, characterized in that a tube ( 2 ) with an output profile cross-section by means of a feed device ( 14 . 15 ) at least once at a tool station ( 13 ) with at least one tool ( 3 ) is passed, the tool ( 3 ) and the pipe ( 2 ) in at least one degree of freedom ( 4 . 8th . 23 ) are arranged to each other adjustable and the tool ( 3 ) the pipe cross-section during the relative movement between pipe ( 2 ) and tools ( 3 ) locally incrementally reshaped. Method according to claim 1, characterized in that the at least one tool ( 3 ) the tube cross-section in the longitudinal direction ( 4 ) is uniformly or partially incrementally non-uniformly formed. Method according to claim 1, characterized in that the at least one tool ( 3 ) in up to three translational and / or at least one rotational degrees of freedom ( 4 . 8th . 23 ) relative to the tube ( 3 ) is moved. Method according to claim 1, characterized in that the tube ( 2 reversing several times at the tool station ( 13 ) is moved past and locally incrementally reshaped. Method according to claim 1, characterized in that the tube ( 2 ) while moving at the tool station ( 13 ) additionally rotatory ( 23 ), preferably rotationally about its longitudinal axis ( 4 ) is turned around. Method according to claim 1, characterized in that the tube ( 2 ) during the forming an axial displacement ( 4 ) and / or a twist ( 23 ) about its longitudinal axis relative to the tool station ( 13 ). Method according to claim 1, characterized in that the at least one tool ( 3 ) a spherical or crowned processing section ( 6 ), which is connected to the pipe ( 2 ) interacts with the incremental transformation. Method according to claim 1, characterized in that the at least one tool ( 3 ) at least one profile cross-section of the pipe to be produced ( 2 ) at least partially adapted processing section ( 6 ), which is connected to the pipe ( 2 ) interacts with the incremental transformation. A method according to claim 1, characterized in that a plurality of, preferably differently shaped tools ( 3 ) one after another, with the tube ( 3 ) are interacting. Method according to claim 1, characterized in that the tube ( 2 ) in addition to the at least one tool ( 3 ) against the forces due to the incremental deformation by a preferably radially attacking support device ( 5 ) is radially supported. Method according to claim 1, characterized in that the tube ( 2 ) end, preferably at one of its ends in a tensioning device ( 17 ) is held. Method according to claim 1, characterized in that the tube ( 2 ) during its movement at the tool station ( 13 ) passing under tensile prestress, preferably between two tensioning devices arranged at each end ( 17 ) is held. Method according to claim 1, characterized in that the relative movements of pipe ( 2 ) and at least one tool ( 3 ) are performed coordinated by means of a control to each other. Method according to claim 1, characterized in that the tube ( 2 ) is stabilized during the local incremental deformation in the region of the pipe wall by an inner support, which in the interior of the profile cross-section of the pipe ( 2 ) is arranged. A method according to claim 1, characterized in that the pipe wall is supported during the local incremental deformation by an internal mandrel, which is arranged in the interior of the pipe cross-section. A method according to claim 1, characterized in that the inner mandrel at least in the region of its effective zone with the at least one tool ( 3 ) relative to the at least one tool ( 3 ) is positioned. A method according to claim 1, characterized in that the pipe wall during the local incremental deformation by a in the interior of the tube ( 2 ), preferably foam-like or honeycomb-like support material is supported, which is arranged in the interior of the tube cross-section. A method according to claim 1, characterized in that the support material according to the Forming inside the formed tube ( 2 ) remains. A method according to claim 1, characterized in that the support material is formed such that the local compression of the support material by the deformation of the tube cross-section causes an additional solidification of the support material. Method according to claim 1, characterized in that the at least one tool ( 3 ) in addition to the relative movements relative to the tube ( 2 ) oscillating small-stroke movements in at least one spatial direction ( 8th ). Method according to claim 1, characterized in that two tubes (at least with associated end regions) are inserted into each other ( 2 ) are formed incrementally so that the two tubes ( 2 ) are positively connected to each other or positively. A method according to claim 1, characterized in that the two nested tubes ( 2 ) are converted together in such a way that in the area of overlap of the tubes ( 2 ) Snap connections or screw connections between the tubes ( 2 ) train. Method according to claim 1, characterized in that the pipe cross-section of the formed pipe ( 2 ) is formed asymmetrically. A method according to claim 1, characterized in that the deformed regions of the tube cross-section functional surfaces, preferably gears, connecting elements, guide surfaces or the like. Form. Contraption ( 12 ) for forming profile tubes ( 2 ), in particular of profile tubes ( 2 ) with cross-sections varying over the longitudinal axis, in particular for carrying out the method according to claim 1, characterized in that the device ( 12 ) a tensioning device ( 17 ) for the incrementally reshapeable tube ( 2 ) and at least one tool station ( 13 ) with at least one tool ( 3 ), wherein the tensioning device ( 17 ) and thus the clamped tube ( 2 ) and the tool station ( 13 ) relative to each other displaceable (4) and / or rotatable ( 23 ) and a single or each tool ( 3 ) in the tool station ( 13 ) at least one relative movement ( 8th ) relative to the tool station ( 13 ), in which the clamped tube ( 2 ) is incrementally transformed. Device according to claim 25, characterized in that the tool station ( 13 ) and / or the tensioning device ( 17 ) of the pipe ( 2 ) movable relative to each other on a common, preferably in the longitudinal direction ( 4 ) of the pipe ( 2 ) machine bed ( 14 ) are arranged. Device according to claim 25 or 26, characterized in that the tensioning device ( 17 ) is designed such that the tensioning device ( 17 ) the pipe ( 2 ) on one side or on both sides endseitig spans. Device according to claim 25 or 26, characterized in that in the tool station ( 13 ) more than one tool ( 3 ) simultaneously, preferably symmetrically relative to the tube ( 2 ) are arranged on the pipe ( 2 ) attack and the tube cross section at the same time in several, separate forming zones incrementally. Device according to claim 28, characterized in that in the tool station ( 13 ) a number of tools ( 3 ) radially and / or axially to the tube ( 2 ) is received relatively movable. Device according to claim 29, characterized in that in the tool station ( 13 ) Recordings for each tool ( 3 ) provided by means of independent drives ( 18 ) the relative movements of the tool ( 3 ) relative to the tube ( 2 ) To run. Device according to one of claims 25 to 30, characterized in that a plurality of tools ( 3 ) by means of a changing station into engagement with the pipe ( 2 ) are brought. Device according to one of claims 25 to 31, characterized in that in the tool station ( 13 ) a number of tools ( 3 ) longitudinal ( 4 ) of the pipe ( 2 ) Staggered relative to the pipe cross-section are arranged adjustable. Device according to claim 32, characterized in that the machining sections (in contact with the pipe cross-section) ( 6 ) in the longitudinal direction ( 4 ) of the pipe ( 2 ) Staggered to each other arranged tools ( 3 ) are formally and dimensionally coordinated. Incrementally formed profile tube ( 11 ), produced in particular by the method according to claim 1 and / or using the device according to claim 25, characterized in that the initial profile ( 2 ) of the profile tube ( 11 ) is formed as a standard hollow profile, preferably round or rectangular, with a constant over its longitudinal extension cross-section. Profile tube according to claim 34, characterized in that the initial profile of the tube ( 2 ) preformed adapted to the executed incremental deformation is formed. Profile tube according to claim 35, characterized in that the initial profile of the tube ( 2 ) is designed as a closed hollow profile. Profile tube according to claim 34 or 35, characterized in that the deformed tube cross-section ( 11 ) has helically arranged to the longitudinal extension of the mold sections. Profile tube according to claim 34 or 35, characterized in that the deformed tube cross-section ( 11 ) has polygonal cross-sectional portions. Profile tube according to claim 34 or 35, characterized in that the deformed tube cross-section ( 11 ) has rounded cross-sectional portions. Profile tube according to claim 34 or 35, characterized in that the deformed tube cross-section ( 11 ) has formed in the longitudinal extension formed and non-formed sections.

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