Forming tool, forming tool assembly, forming machine, forming method and computer program for producing a cylindrical workpiece having a helical outer contour by means of swaging

Abstract

A forming tool for a forming tool assembly for producing a cylindrical workpiece has a helical outer contour in multiple stages by means of swaging, the forming tool including a force-application side, a forming side located opposite the force-application side, and a cam structure formed on the forming side. The cam structure has a first forming cam and a second forming cam which are located one behind the other in a longitudinal direction of the forming tool perpendicular to the forming direction. The forming cams have various cam heights and the forming cams have a cam extension direction in an orthogonal view of the forming side, which cam extension direction is oblique in relation to the longitudinal direction of the forming tool. The forming tool is used in a forming tool assembly, a forming machine and a forming method, and a computer program is used to control the forming method.

Description

[0001] The invention relates to a forming tool for a forming tool arrangement for producing a cylindrical workpiece with a helical outer contour in multiple stages by swaging, the forming tool having a forming side with a cam structure formed on the forming side.

[0002] The invention also relates to a forming tool arrangements with such a forming tool and a forming machine with a forming tool arrangement.

[0003] The invention further relates to a forming method and a computer program for controlling the forming machine during the performance of the method.

[0004] Components with a helical outer contour are widely used. For example, they are used in connection with screw drives, in which threaded rods or threaded spindles are used to convert a rotational movement into a linear movement. Typical applications include scissor jacks, linear guides on machine tools or steering spindles on motor vehicles. Depending on the specific application, different thread shapes are provided, e.g. ball threads or trapezoidal threads, which can be designed as right-hand or left-hand threads.

[0005] The helical outer contour is typically produced by means of machining processes. For example, a method for machining a ball screw is known from DE 10 2014 225 104 B4.

[0006] Such processes lead to relatively high manufacturing costs when creating the helical outer contour. If, in addition, increased strength of the manufactured components is to be achieved, further post-treatment processes must be provided following the production of the helical outer contour. As a result, manufacturing costs are further increased.

[0007] It is therefore an object of the invention to provide an alternative and cost-effective manufacture of components with a helical outer contour.

[0008] This object is achieved according to the invention by a forming tool having the characterizing features of patent claim 1, a forming tool arrangement according to patent claim 10, a forming machine according to patent claim 15, a forming method according to patent claim 16 and a computer program according to patent claim 18. The dependent claims relate to preferred embodiments of the invention.

[0009] According to the invention, a forming tool or a forming jaw is provided. The forming tool is designed for arrangement in a forming tool arrangement, in particular a swaging unit. In addition, the forming machine is suitable for the multi-stage production of a cylindrical workpiece with a helical outer contour by swaging. Preferably, the cylindrical workpiece is produced from a cylindrical workpiece blank.

[0010] According to the invention, production in multiple stages includes the serial or locally spaced action of the same forming tool and / or different forming tools on the same region of the workpiece blank, wherein each stage contributes a gradual portion to the overall forming.

[0011] The forming tool has a force introduction side for introducing a forming force into the forming tool. The force introduction side is preferably designed to be flat, as a result of which a particularly uniform force introduction can carried out.

[0012] The forming tool also has a forming side opposite the force introduction side. The forming side is designed to introduce the forming force into the workpiece blank. In other words, the forming side is at least temporarily in engagement with the workpiece blank during the production of the cylindrical workpiece. The forming force is introduced in one forming direction. The forming direction is typically equal to a radially inward direction of the cylindrical workpiece to be manufactured.

[0013] The force introduction side can be inclined to the forming direction. As a result, the distance of the forming tool, when arranged in a forming tool arrangement, can be adjusted in a controlled manner by applying an adjusting wedge to the workpiece blank. Typically, the distance of the forming tool to the workpiece blank is adjusted depending on the outer diameter of the workpiece blank. By means of the adjusting wedge, the distance between the forming tool and the workpiece blank can also be adapted to an outer diameter of the workpiece blank that is reduced, for example due to forming. In other words, the forming tool can be readjusted by means of the adjusting wedge.

[0014] The forming tool has a cam structure formed on the forming side. The cam structure can effect a radial depression or notch in order to produce the helical outer contour on the workpiece blank.

[0015] Furthermore, the cam structure has at least a first forming cam and a second forming cam. In addition, the cam structure can have additional forming cams. The forming cams are arranged one behind the other in a longitudinal direction of the forming tool perpendicular to the forming direction. In other words, the forming cams of the cam structure are arranged in a row in the longitudinal direction. The longitudinal direction can correspond to a workpiece feed direction of a workpiece blank to be formed in a forming process during the production of a cylindrical workpiece with a helical outer contour.

[0016] Each forming cam has a cam height, typically in the forming direction. According to the invention, the cam heights of at least two forming cams are different. In other words, at least one forming cam protrudes, typically in the forming direction, relative to at least one other forming cam. For example, the first forming cam has a different cam height than the second forming cam if the cam structure comprises only two forming cams. In the case of further forming cams, two or more forming cams can have the same cam height, provided that at least one further forming cam has a different cam height. Due to the different cam heights, a multi-stage, in other words stepped, forming of the helical outer contour in the forming direction is made possible. The forming tool can therefore penetrate the workpiece blank to be formed in a plurality of stages during a forming process, without the forming tool having to be readjusted in the forming direction.

[0017] The forming cams have, in an orthogonal view of the forming side, a cam direction that is formed obliquely to the longitudinal direction of the forming tool. The cam direction is preferably deflected by a pitch angle relative to a transverse direction perpendicular to the longitudinal direction. The pitch angle can be between 1 degree and 89 degrees, preferably between 5 degrees and 45 degrees, particularly preferably between 10 degrees and 30 degrees. Typically, the cam direction has the same pitch angle as the helical outer contour of the workpiece to be manufactured.

[0018] In summary, the forming tool according to the invention has a cam structure that is formed by the forming cams, in portions complementary to the helical outer contour to be produced of the cylindrical workpiece. The helical outer contour can be produced by the forming cams acting on the workpiece blank at least twice, forming a helical notch or depression. Typically, a helical relative movement between the forming tool and the workpiece blank to be formed is superimposed on the forming process.

[0019] In a preferred embodiment of the forming tool, the forming side has a forming groove extending in the longitudinal direction. The forming groove typically has a groove base that is circular-segment-shaped in cross section. The cam structure is typically, in particular completely, arranged in the forming groove.

[0020] A further development of the forming tool is also preferred in which the forming groove has a groove portion with a cross section tapering in the longitudinal direction, or in the workpiece feed direction (inlet portion). Typically, in this case the groove base has a circular segment radius that decreases in the longitudinal direction. In particular, the circle segment radius decreases from a radius of the workpiece blank to an outer radius of the helical outer contour of the workpiece to be manufactured.

[0021] Alternatively or additionally, the forming groove can have a groove portion with a constant cross section in the longitudinal direction or in the workpiece feed direction (calibration portion).

[0022] The cam structure can have at least one forming cam arranged in the groove portion tapered cross section and / or arranged in the groove portion with a constant cross section. Preferably, the forming groove has both an inlet portion and a calibration portion, in each case with at least one forming cam arranged therein, wherein the calibration portion is formed downstream of the inlet portion in the longitudinal direction. As a result, the helical outer contour can be produced with particular precision.

[0023] In a preferred embodiment of the forming tool, the cam structure has at least three, preferably at least six, particularly preferably at least twelve, forming cams. Due to the higher number of forming cams, the gradual contribution of a single forming cam to the overall forming process during the production of the helical outer contour can be reduced. This can increase the manufacturing accuracy of the helical outer contour. Alternatively or additionally, the production of a helical outer contour with a plurality of turns, in particular thread turns, can be improved by a larger number of forming cams.

[0024] The forming cams are preferably arranged equidistant from one another in the longitudinal direction. In other words, forming cams of the cam structure that are adjacent in the longitudinal direction in each case have the same distance from one another. As a result, for example, a multi-start helical outer contour with equal distance between the individual starts or with uniform pitch can be produced.

[0025] Furthermore, an embodiment of the forming tool is preferred in which at least one, preferably a plurality, particularly preferably all of the forming cams has or have a forming portion curved about the longitudinal direction. The curved forming portion can be understood as a part of the forming cam that produces a root circle of the helical outer contour to be produced. As a result, a portion of the corresponding forming cam acting on the workpiece blank can be made larger in the cam direction, as a result of which a larger outer region of the workpiece blank can be formed.

[0026] In a preferred embodiment of the forming tool, at least one of the forming cams has a cam contour that is curved, triangular or trapezoidal in the longitudinal direction, or in the workpiece feed direction. Preferably, a first forming cam of the cam structure has a curved cam contour in the longitudinal direction. Further preferably, the cam contours of the forming cams following the first forming cam, in particular a profile shape, approximate the helical outer contour of the cylindrical workpiece to be produced. It is particularly preferable that the cam contour is increasingly adapted to the helical outer contour to be produced as the degree of forming of the workpiece blank by the forming cams increases. The inventors have recognized that, as a result, the manufacturing quality of the cylindrical workpiece with a helical outer contour can be increased.

[0027] Further preferred is an embodiment of the forming tool in which at least one of the forming cams has a first cam flank and a second cam flank. A cam flank is to be understood as a forming portion of the forming cam that is predominantly formed in the cam direction, wherein the forming portion causes a continuous flank of the helical outer contour to be produced. The first and second cam flanks of a forming cam typically form opposite flanks of the same notch of the helical outer contour. Preferably, a plurality of forming cams of the cam structure have a first and a second cam flank. At least one forming cam of the cam structure, typically the last one formed in the longitudinal direction, has a first and a second cam flank that corresponds to a flank shape of the helical outer contour to be produced. The first cam flank and the second cam flank are typically inclined to the forming direction. As a result, manufacturing quality can be further improved.

[0028] Alternatively or additionally, at least one forming cam can have an inlet portion and / or outlet portion formed in the cam direction. The inlet portion is preferably designed as a portion tapering opposite to the cam direction. The outlet portion is preferably designed as a portion tapering in the cam direction. The inlet portion or the outlet portion can make it possible for the forming cam to be easily inserted or removed into or from an existing notch on the outer contour of the workpiece blank during the forming of a workpiece blank. In a particular embodiment, the inlet portion is arranged upstream of the forming portion having the cam flanks in the cam direction and the outlet portion is arranged downstream of the forming portion having the cam flanks in the cam direction.

[0029] In a preferred development of the forming tool, the first and second cam flanks of at least one forming cam form a cam angle of at most 40 degrees, preferably of at most 30 degrees, particularly preferably of at most 20 degrees. The cam angle can correspond to a flank angle of the helical outer contour to be produced. A smaller cam angle makes it possible for the formation of a steeper flank angle on the helical outer contour to be produced.

[0030] An embodiment of the forming tool is preferred in which the forming tool has a forming tool portion that tapers in the forming direction. Preferably, the forming tool portion is trapezoidal in a view projected in the longitudinal direction. In other words, the forming side has a reduced area compared to the force introduction side. As a result, a forming force introduced via the force introduction side can be concentrated on a smaller forming surface on the workpiece blank.

[0031] The underlying object is also achieved by a forming tool arrangement, for example a swaging unit, for a forming machine for the production in multiple stages of a cylindrical workpiece with a helical outer contour by swaging.

[0032] The forming tool arrangement has at least one first forming tool described above and in the following, and at least one second forming tool described above and in the following. In addition, the forming tool arrangement can have further forming tools as described above and in the following. The forming tools are preferably of the same construction, or of identical design. As a result, costs in the production of the forming tool arrangement can be avoided by using a higher number of identical parts.

[0033] The forming tools are arranged concentrically about a center axis of the forming tool arrangement. Typically, the center axis of the workpiece blank arranged in the forming tool arrangement corresponds to a workpiece axis of the workpiece blank. The forming tools at least partially enclose the workpiece blank during the production of the helical outer contour.

[0034] The forming tools are aligned with their respective forming sides in the direction of the center axis. In other words, the forming tools are aligned radially inwards. The forming tool arrangement is designed for radially deflecting the forming tools in the direction of the center axis. In other words, the forming tools are deflected by the forming tool arrangement according to their particular forming direction. Typically, the forming tools are moved towards one another. Due to the radial deflection of the forming tools, a radial force introduction in the particular forming direction of a forming tool into the workpiece blank to be formed can be achieved.

[0035] According to the invention, the first forming cam of the first forming tool is arranged on a first helical line together with one of the forming cams of the second forming tool. In other words, forming cams of different forming tools are arranged on a common helical line. The production of the helical outer contour can therefore be achieved by multi-stage action of forming cams of different forming tools on the same workpiece portion of the workpiece blank.

[0036] The forming tool arrangement can also have an outer ring, a roller cage that can be driven by a motor, in particular by means of the outer ring, a guide insert and at least two plungers. The roller cage is typically arranged concentrically within the outer ring and is designed for arrangement of a plurality of rollers rotatably supported on the roller cage. The rollers can protrude radially outwards and radially inwards beyond the roller cage. The roller cage is typically in permanent contact with the outer ring by means of the rollers on the radially outer side. The guide insert is typically arranged within the roller cage and is designed to accommodate the forming tools and, in particular, the plungers in a radially movable manner. When using plungers, in each case one plunger and one forming tool can form a common forming punch. In other words, the plunger and forming tool are deflected radially together. Typically, the plungers protrude radially outward beyond the guide insert and are designed to temporarily contact the rollers of the roller cage. During operation of the forming tool arrangement, the roller cage is in rotational movement, wherein the rollers regularly roll over the plungers and thereby deflect them in the radial direction. In other words, each time the plunger rolls over, a radially inwardly directed forming impact is caused. The impact rate is a function of the rotational speed of the roller cage.

[0037] In a preferred embodiment of the forming tool arrangement, the second forming cam of the first forming tool is arranged on the first helical line. Such an arrangement of the forming tools makes it possible, for example, to produce a helical outer contour with only one thread. Alternatively, it can be provided that the second forming cam of the first forming tool is arranged on a second helical line together with one of the forming cams of the second forming tool. As a result, for example, a helical outer contour with at least two threads can be produced.

[0038] Further preferred is an embodiment of the forming tool arrangement in which both forming cams of the second forming tool are arranged on the first helical line. As a result, the gradual contribution of the individual forming tools along with the gradual contribution of the individual forming cams to the overall forming process, or the formation of the helical notch, can be reduced, as a result of which manufacturing quality can be further increased.

[0039] In a preferred embodiment of the forming tool arrangement, it has at least one further forming tool described here and in the following. According to the embodiment, one of the forming cams of the further forming tool can be arranged on the first helical line. As a result, the gradual contribution of the individual forming cams can be further reduced and manufacturing quality can be further increased. Alternatively or additionally, it can be provided that one of the forming cams of the further forming tool is arranged on the second helical line. As a result, manufacturing quality can be increased when creating a helical outer contour with two threads.

[0040] Also preferred is an embodiment of the forming tool arrangement in which the forming tools have a plurality of, preferably at least six, particularly preferably at least twelve, forming cams. The first forming cams of the forming tools are preferably arranged on different helical lines. Particularly preferably, the forming cams of a forming tool following the first forming cam in the particular longitudinal direction are arranged alternately with the helical line of the same workpiece on the helical lines of the further forming tools. In other words, the forming tool arrangement is designed to form a number of threads on the helical outer contour that is equal to the number of forming tools. Typically, the forming tools in this case are of the same, in particular identical, design and are arranged in the forming tool arrangement along the center axis without any offset to one another.

[0041] The underlying object of the invention is also achieved by a forming machine. The forming machine is suitable for the multi-stage production of a cylindrical workpiece with a helical outer contour by swaging.

[0042] The forming machine has the forming tool arrangement described here and in the following.

[0043] In addition, the forming machine has a feed device. The feed device is designed for arranging, in particular clamping, the workpiece blank. Typically, the feed device comprises a chuck for this purpose. Furthermore, the feed device is designed to be translationally movable relative to the forming tool arrangement in the workpiece feed direction or along the center axis of the forming tool arrangement.

[0044] In addition, the forming machine comprises a machine controller designed to regulate machine parameters. Typically, the machine control system regulates at least the rotational speed of the forming tool arrangement and a feed rate of the feed device. In addition, the forming machine is designed for performing a relative rotational movement between the forming tool arrangement and the feed device. In other words, when the workpiece blank is arranged, the forming machine is designed to carry out a rotational movement of the workpiece blank relative to the forming tools.

[0045] In a particular embodiment of the forming machine, it can be provided that the forming machine has a mandrel device. The mandrel device typically comprises a forming mandrel that is arranged within a hollow cylindrical workpiece blank prior to a forming process. The mandrel device is preferably arranged on the feed device.

[0046] Furthermore, the underlying object is achieved by a forming method. The forming method is suitable for the multi-stage production of a cylindrical workpiece with a helical outer contour by swaging.

[0047] The forming method is performed by means of a forming machine described here and in the following and comprises the following method steps.

[0048] One method step provides arranging, in particular clamping, a workpiece blank on the forming machine. Preferably, the workpiece blank is clamped in the feed device, in particular by means of a provided chuck. Typically, the workpiece blank is arranged on the forming machine in such a way that a workpiece axis of the workpiece blank coincides with the center axis of the forming tool arrangement.

[0049] A further method step provides for the production of the cylindrical workpiece with the helical outer contour by moving the feed device in the workpiece feed direction and simultaneously performing the relative rotational movement between the forming tool arrangement and the feed device.

[0050] The relative rotational movement is adapted to the movement in the workpiece feed direction in such a way that the forming cams along the helical lines bring about a plastic deformation of the workpiece blank, in particular a helical notch on the outside of the workpiece blank, by radial deflection of the forming tools.

[0051] The inventors have recognized that a feed rate for the movement in the workpiece feed direction is preferably less than 50 millimeters per second in order to ensure good manufacturing quality with short manufacturing time. The feed rate is particularly preferably between 5 and 30 millimeters per second. As a result, a particularly high manufacturing quality can be ensured.

[0052] Furthermore, the inventors have recognized that an impact rate of the forming tools of between 10 and 100 strokes per second, preferably between 20 and 60 strokes per second, particularly preferably 40 strokes per second, results in a high surface quality on the workpiece.

[0053] Preferably, the relative rotational movement between the forming tool arrangement and the feed device, or the workpiece blank, is adapted to the impact rate. As a result, a so-called transfer angle between two successive forming impacts can be predetermined. A transfer angle of at most 40 degrees, preferably of at most 20 degrees, particularly preferably of at most 5 degrees, has proven to be particularly advantageous with regard to the manufacturing quality of the helical outer contour of the workpiece that is in particular to be produced.

[0054] In a preferred embodiment of the forming process, the cylindrical workpiece is produced from a hollow workpiece blank. According to the embodiment, it can be provided that a forming mandrel is arranged within the hollow workpiece blank before the cylindrical workpiece with the helical outer contour is produced. In other words, the helical outer contour is produced over a forming mandrel. As a result, a workpiece with a precise inner contour can be produced, because a radial material flow during the forming is prevented by the forming mandrel.

[0055] In addition, the underlying object is achieved by a computer program.

[0056] The computer program is set up to operate the forming machine described above and in the following. According to the embodiment, the forming machine provides a numerical machine controller.

[0057] The computer program comprises control commands for the machine controller that cause the forming process described here and in the following to be performed by the forming machine if the computer program is running on the numerical machine controller of the forming machine.

[0058] Further features and advantages of the invention can be found in the description, the claims, and the drawings. Likewise, the aforementioned features and those which are to be explained below can each be used individually or severally in expedient combinations of any kind. The embodiments shown and described are not to be understood as an exhaustive list, but, rather, have an exemplary character for the description of the invention.

[0059] In the following, the invention is explained in more detail on the basis of schematic illustrations given by way of example.In the Figures:

[0060] FIG. 1 shows a forming machine with a forming tool arrangement and a feed device in a perspective view.

[0061] FIG. 2 shows a first embodiment of a forming tool arrangement with a roller cage, a plurality of plungers and a plurality of forming tools in a perspective view.

[0062] FIG. 3 shows a partial view of a second embodiment of a forming tool arrangement with a plurality of forming tools in a sectional side view.

[0063] FIG. 4 shows the forming tool arrangement from FIG. 3 with the workpiece blank arranged therein.

[0064] FIG. 5 shows an alternative forming tool arrangement with a workpiece blank arranged therein.

[0065] FIG. 6 shows a forming tool of the forming tool arrangement from FIGS. 3 and 4 in an orthogonal view of a forming side.

[0066] FIG. 7 shows the forming tool from FIG. 6 in a perspective view.

[0067] FIG. 8 shows a partial detail of the forming tool from FIGS. 6 and 7 in a sectional view.

[0068] According to FIG. 1, a forming machine 10 has a forming tool arrangement 12 and a partially shown feed device 14. By means of the feed device 14, a workpiece blank 18, e.g. a pipe, clamped on a chuck 16 can be fed along a feed axis 20 of the feed device 14 or along a center axis 22 of the forming tool arrangement 12.

[0069] The feed axis 20 coincides with a longitudinal axis 24 of the clamped workpiece blank 18. The clamped workpiece blank 18 with a longitudinal workpiece portion to be machined can be inserted into the forming tool arrangement 12 via an insertion opening 26 on a front side 28 of the forming tool arrangement 12. In other words, the workpiece blank 18 can be subjected to an axial movement 29 in the direction of the forming tool arrangement 12.

[0070] The feed device 14 is designed for effecting a rotational movement 30 of the workpiece blank 18 about the feed axis 20. For this purpose, the feed device 14 comprises drive means not shown in detail. The feed device 14 is designed to superimpose the axial movement 29 on the rotational movement 30.

[0071] The forming machine 10 or the forming tool arrangement 12 can have a drive unit, not shown in detail, typically an electric motor.

[0072] The drive unit is typically designed to drive the forming tool arrangement 12.

[0073] The forming machine 10 further has a machine controller 34 for controlling the forming machine 10. For this purpose, the machine controller 34 is connected to the forming tool arrangement 12 and the feed device 14 via schematically shown communication connections 36.

[0074] FIG. 2 shows a forming tool arrangement 12 as a solitary assembly.

[0075] As shown, the forming tool arrangement 12 comprises a roller cage 38, a plurality of rollers 42 arranged on the roller cage 38, a plurality (here four) of plungers 44 and an equal number of forming tools 46. In each case, a plunger 44 and a forming tool 46 together form a forming punch 48. In addition, as shown, each forming punch 48 has an adjusting wedge 50 arranged between the plunger 44 and the forming tool 46. For reasons of clarity, only one roller 42, one plunger 44, one forming tool 46, one forming punch 48 and one adjusting wedge 50 are provided with a reference sign.

[0076] The rollers 42 are rotatably arranged on the roller cage 38. As shown, the roller cage 38 can have cylindrical recesses into which the rollers 42 are inserted parallel to the center axis 22.

[0077] The roller cage 38 is designed concentrically to the center axis 22 and has a radially outer side 52 and a radially inner side 54. The rollers 42 project radially beyond the roller cage 38 on the radially outer side 52 and on the radially inner side 54. Typically, the rollers 42 rest on the radially outer side 52 against an outer ring (not shown in detail), or the roller cage 38 is supported on the outer ring by means of the rollers 42.

[0078] The forming punches 48 are arranged within the roller cage 38 in such a way that a forming side 56 of the forming tools 46 is oriented radially inwardly in the direction of the center axis 22 of the forming tool arrangement 12 or in a forming direction 58 of the forming tools 46. As shown, the forming tools 46 are arranged concentrically to the center axis 22.

[0079] Furthermore, according to the embodiment shown, the forming dies 48 are arranged uniformly distributed over a radial inner circumference of the roller cage 38 or the radially inner side 54 of the roller cage 38.

[0080] During operation of the forming tool arrangement 12, the roller cage 38 is set into a rotational movement 60 relative to the forming punches 48. The rollers 42 pass the plungers 44, as a result of which the plungers are displaced radially inwards and cause a forming force in the forming direction 58. Depending on the rotational speed of the roller cage 38 and the number of rollers 42, an impact rate is predetermined, which defines the number of forming movements per unit of time.

[0081] By means of the adjusting wedge 50, a radial extension of the forming punch 48 is adapted to an outer diameter of a workpiece blank 18 to be formed. For this purpose, the adjusting wedge can be moved parallel to the center axis 22 in order to reduce or increase the radial extent of the forming punch 48.

[0082] FIG. 3 shows a tool arrangement 12 in a sectional side view of a sectional plane X-X marked in FIG. 2. The tool arrangement 12 has four identical forming tools 46, of which, however, only three forming tools 46 can be seen due to the sectional representation. The forming tools 46 are arranged concentrically about the center axis 22 of the tool arrangement 12.

[0083] Each forming tool 46 has a force introduction side 62 and a forming side 64 opposite the force introduction side 62. For forming a workpiece blank 18, a force is introduced into the forming tool 46 via the force introduction side 62 and is introduced via the forming side 64 into the workpiece blank 18 to be formed. In other words, a force is exerted in the forming direction 58. The forming direction 58 of each forming tool 46 is typically directed toward the center axis 22 of the forming tool arrangement 12.

[0084] The force introduction side 62 of a forming tool 46, preferably the force introduction sides 62 of all forming tools 46, can be formed obliquely to the forming direction 58, as shown. In other words, the force introduction side 62 can enclose an angle 66 with a plane 68 perpendicular to the forming direction 58. As a result, an adjusting wedge 50 (see FIG. 2) can be arranged on the force introduction side 62, wherein the adjusting wedge 50 preferably has a wedge angle that is identical to the angle 66.

[0085] The forming sides 64 of the forming tools 46 in each case have a cam structure 70. Each cam structure 70 has a plurality (here fourteen) of forming cams 72. For reasons of clarity, only two cam structures 70, and in each case a first forming cam 72 of the two cam structures 70 in the longitudinal direction 74 of the particular forming tool 46, are provided with a reference sign.

[0086] The forming cams 72 of each cam structure 70 are arranged one behind the other in the longitudinal direction 74 of the particular forming tool 46. The longitudinal direction 74 preferably runs in the same direction as the axial movement 29 (see FIG. 1) of a workpiece blank 18 (see FIG. 1) during the production of a cylindrical workpiece.

[0087] FIG. 4 shows the tool arrangement 12 from FIG. 3 with a workpiece blank 18 situated in the tool arrangement 12, for explaining the production of a cylindrical workpiece with a helical outer contour.

[0088] For this purpose, the workpiece blank 18 is fed to the forming tool arrangement 12 with a feed movement 76, which results from a superposition of the axial movement 29 and the rotational movement 30. The workpiece blank 18 is moved along the center axis 22 between the forming tools 46, wherein the forming tools 46 temporarily act radially on the workpiece blank 18 in the particular forming direction 58. The forming sides 64, in particular the cam structures 70, cause a plastic deformation of the workpiece blank 18. The forming cams 72 form a notch 78 on the workpiece blank 18, which produces a helical outer contour due to the feed movement 76.

[0089] The axial movement 29 is coordinated with the rotational movement 30 in such a way that, due to the resulting feed movement 76, a portion of the workpiece blank 18 that has been formed by a forming cam 72 of a first forming tool 46 is fed to a forming cam 72 of a forming tool 46 that is immediately downstream in the direction of rotation of the rotational movement 30. In other words, the notch 78 started by a forming cam 72 is continuously formed in multiple stages by further forming cams 72 of further forming tools 46. As shown, the notch 78 can be produced by different forming cams 72 of different forming tools 46 and different forming cams 72 of the same cam structure 70 of a forming tool 46.

[0090] Individual and / or multiple forming cams 72 of one and / or multiple forming tools 46 are therefore arranged on at least one common first helical line 80. As shown, the notch 78 runs along the first helical line 80. For reasons of clarity, only one notch 78 is shown in FIG. 4. Furthermore, it is self-explanatory that according to the embodiment shown, further notches 78, for example along a second helical line 82, can be formed by the forming sides 64. The number of helical lines 80, 82 is preferably equal to the number of forming tools 46.

[0091] As shown, during the production of the cylindrical workpiece with the helical outer contour, an initial diameter 84 of the workpiece blank 18 is reduced to a final diameter 86. In other words, the workpiece blank 18 is subjected to a diameter reduction.

[0092] FIG. 5 shows an alternative tool arrangement 12 in a sectional side view analogous to the sectional plane X-X marked in FIG. 2. The tool arrangement 12 has four different forming tools 46. Due to the sectional representation, only three forming tools 46 can be seen in FIG. 5. The forming tools 46 are arranged concentrically about the center axis 22 of the tool arrangement 12.

[0093] The cam structures 70 of the various forming tools 46 are coordinated with one another along the center axis 22, or are formed on the particular forming tool 46, in such a way that a helical outer contour with only a single notch 78 is formed. In other words, the helical outer contour has only one thread.

[0094] According to the embodiment shown, all forming cams 72 of the particular cam structure 70 and all forming cams 72 of the other forming tools 46 are located on the (here only one) helical line 80.

[0095] The forming method for producing the helical outer contour can be used in the same way as described in FIG. 4.

[0096] FIG. 6 shows a single forming tool 46 in a plan view of the forming side 64.

[0097] The forming side 64 has a forming groove 88. As shown, the cam structure 70 can be arranged completely within the forming groove 88.

[0098] The forming groove 88 has an inlet portion 90 with a tapered cross section. The inlet portion 90 is designed to reduce the diameter of a workpiece blank 18 to be formed (see FIG. 4). Preferably, the cam structure 70 has at least one forming cam 72 in the inlet portion 90. As shown, the cam structure 70 has seven forming cams 72 arranged completely in the inlet portion 90.

[0099] The forming groove 88 here also has a calibration portion 92 with a cross section that remains constant. The calibration portion 92 is designed for fine forming of the workpiece blank 18. Typically, the gradual contribution of a total forming at the forming cams 72 in the calibration portion 92 is less than the gradual contribution of the forming cams 72 in the inlet portion. For this purpose, according to the embodiment shown, the calibration portion 92 has five forming cams 72 of the cam structure 70 arranged completely in the calibration portion 92.

[0100] The forming cams 72 of the cam structure 70 have a cam direction 94 which deviates from a transverse direction 96 running perpendicular to the longitudinal direction 74 with a pitch angle 98. In other words, the cam direction 94 runs obliquely to the longitudinal direction 74. Preferably, all forming cams 72, as shown, have the same cam direction 94. In other words, the forming cams 72 are parallel to one another.

[0101] FIG. 7 shows the forming tool 46 from FIG. 6 in a perspective view.

[0102] According to the embodiment shown, the forming tool 46 has a forming tool portion 100 that tapers in the forming direction 58. The forming tool portion 100 has, on its side facing away from the force introduction side 62, the forming groove 88 with the cam structure 70 arranged or formed therein.

[0103] The forming groove 88 typically has a groove base 102 that is circular-segment-shaped in its cross section. As a result, a circular cross section of the workpiece blank 18 can be maintained and / or produced during forming.

[0104] FIG. 8 shows an enlarged partial detail of the forming tool 46 of FIGS. 6 and 7 in a longitudinal section through the forming groove 88 and the cam structure 70.

[0105] The cam structure 70 has forming cams 72a with a cam contour 104 curved in the longitudinal direction 74. Furthermore, as shown, the cam structure 70 can have forming cams 72b with a trapezoidal cam contour 106 extending in the longitudinal direction 74. For reasons of clarity, only one forming cam 72a, one forming cam 72b, one curved cam contour 104 and one trapezoidal cam contour 106 are provided with a reference sign. As shown, the first forming cams 72 in the longitudinal direction 74 have the curved cam contour 104 and the last forming cams 72 in the longitudinal direction 74 have the trapezoidal cam contour 106.

[0106] The forming cams 72, in particular the forming cams 72b with trapezoidal cam contour 106, can have a first cam flank 108 and a second cam flank 110. The first cam flank 108 is positioned upstream of the second cam flank 110 in the longitudinal direction 74. The first cam flank 108 and the second cam flank 110 of the same forming cam 72 form a cam angle 112. The first cam flank 108 and the second cam flank 110, or the second cam flank 110 and the first cam flank 108, of adjacent forming cams 72 form a notch angle 114.

[0107] A cam height 116 of each forming cam 72 is measured between a cam peak 118 and the groove base 102 in the forming direction 58. The cam height 108 preferably increases in the longitudinal direction 74, in particular continuously.List of reference signsforming machine 10;forming tool arrangement 12;feed device 14;chuck 16;workpiece blank 18;feed axis 20;center axis 22;longitudinal axis 24;insertion opening 26;front 28;axial movement 29;rotational movement 30;machine controller 34;communication connections 36;roller cage 38;rollers 42;plunger 44;forming tool 46;forming stamp 48;adjusting wedge 50;radial outer side 52;radial inner side 54;forming side 56;forming direction 58;rotational movement 60;force introduction side 62;forming side 64;angle 66;plane 68;cam structure 70;forming cam 72, 72a, 72b;longitudinal direction 74;feed movement 76;notch 78;first helical line 80;second helical line 82;initial diameter 84;final diameter 86;forming groove 88;inlet portion 90;calibration portion 92;cam direction 94;transverse direction 96;pitch angle 98;forming tool portion 100;groove base 102;curved cam contour 104;trapezoidal cam contour 106;first cam flank 108;second cam flank 110;cam angle 112;notch angle 114;cam height 116;cam peak 118;cutting plane X-X.

Claims

1. A forming tool (46) for a forming tool arrangement (12) for multi-stage production of a cylindrical workpiece with a helical outer contour by rotary swaging, comprisinga force introduction side (62) for introducing a forming force into the forming tool (46);a forming side (64) opposite the force introduction side (62) for introducing the forming force in a forming direction (58) into the workpiece blank (18); anda cam structure (70) formed on the forming side (64);whereinthe cam structure (70) has a first forming cam (72; 72a, 72b) and a second forming cam (72; 72a, 72b) which are arranged one behind the other in a longitudinal direction (74) of the forming tool (46) perpendicular to the forming direction (58); whereinthe forming cams (72; 72a, 72b) have different cam heights (116); and whereinthe forming cams (72; 72a, 72b) in an orthogonal view of the forming side (64) have a cam direction (94) which is formed obliquely to the longitudinal direction (74) of the forming tool (46).

2. The forming tool (46) according to claim 1, wherein the forming side (64) has a forming groove (88) which extends in the longitudinal direction (74) and has a groove base (102) that is circular segment-shaped in cross section, wherein the cam structure (70) is arranged in the forming groove (88).

3. Forming The forming tool (46) according to claim 2, wherein the forming groove (88) has an inlet portion (90) having a cross section which tapers in the longitudinal direction (74) and / or a calibration portion (92) having a cross section which is constant in the longitudinal direction (74), wherein at least one of the forming cams (72; 72a, 72b) is arranged in the inlet portion (90) and / or in the calibration portion (92).

4. The forming tool (46) according to claim 1, wherein the cam structure (70) has at least three forming cams (72; 72a, 72b) which are arranged equidistant from one another in the longitudinal direction (74).

5. The forming tool (46) according to claim 1, wherein at least one of the forming cams (72; 72a, 72b) has a forming portion which is curved around the longitudinal direction (74) or towards the longitudinal direction (74).

6. The forming tool (46) according to claim 1, wherein at least one of the forming cams (72; 72a, 72b) has a cam contour (104, 106) which is curved and / or trapezoidal in the longitudinal direction (74).

7. The forming tool (46) according to claim 1, wherein at least one of the forming cams (72; 72a, 72b) has a first cam flank (108) and a second cam flank (110), wherein the first cam flank (108) and the second cam flank (110) are inclined to the forming direction (58).

8. The forming tool (46) according to claim 7, wherein the first and the second cam flank (108, 110) of at least one forming cam (72; 72a, 72b) form a cam angle (112) of at most 40 degrees.

9. The forming tool (46) according to claim 1, wherein the forming tool (46) has a forming tool portion (100) which tapers in the forming direction (58).

10. A forming tool arrangement (12) for a forming machine (10) for the multi-stage production of a cylindrical workpiece with a helical outer contour by rotary swaging, comprisingtwo of the forming tools according to claim 1, the two forming tools comprising a first forming tool (46) and a second forming tool (46);wherein the forming tools (46) are arranged concentrically about a central axis (22) of the forming tool arrangement (12) in order to at least partially enclose a workpiece blank (18) when producing the cylindrical workpiece with a helical outer contour;wherein the forming tool arrangement (12) is designed for radially deflecting the forming tools (46) in the direction of the central axis (22);wherein the forming tools (46) are each aligned with their forming side (64) in the a direction of the central axis (22) in order to be able to cause a radial force to be introduced into the workpiece blank (18) by the radial deflection;wherein the first forming cam (72; 72a, 72b) of the first forming tool (46) is arranged together with one of the forming cams (72; 72a, 72b) of the second forming tool (46) on a first helical line (80).

11. The forming tool arrangement (12) according to claim 10, wherein the second forming cam (72; 72a, 72b) of the first forming tool (46) is arranged on the first helical line (80) or together with one of the forming cams (72; 72a, 72b) of the second forming tool (46) on a second helical line (82).

12. The forming tool arrangement (12) according to claim 10, wherein both forming cams (72; 72a, 72b) of the second forming tool (46) are arranged on the first helical line (80).

13. The forming tool arrangement (12) according to claim 11, additionally comprising at least one further forming tool (46), wherein one of the forming cams (72; 72a, 72b) of the at least one further forming tool (46) is arranged on the first helical line (80) and / or the second helical line (82).

14. The forming tool arrangement (12) according to claim 10, wherein the forming tools (46) have a plurality of forming cams (72; 72a, 72b); wherein the first forming cams (72; 72a, 72b) of the forming tools (46) are arranged on different helical lines (80, 82); wherein the forming cams (72; 72a, 72b) of a forming tool (46) following in the longitudinal direction (74) of the first forming cam (72; 72a, 72b) are arranged on the helical lines (80, 82) of the further forming tools (46) alternating with the helical line (80, 82) of the same forming tool (46).

15. A forming machine (10) for the multi-stage production of a cylindrical workpiece with a helical outer contour by rotary swaging, comprising:the forming tool arrangement (12) according to claim 10;a feed device (14) designed for arranging, in particular clamping, a workpiece blank (18); wherein the feed device (14) is designed to be translationally movable along a feed axis (20) relative to the forming tool arrangement (12); anda machine controller (34) designed to regulate machine parameters;wherein the forming machine (10) is designed to carry out a relative rotational movement (30) between the forming tool arrangement (12) and the feed device (14).

16. A forming method for the multi-stage production of a cylindrical workpiece with a helical outer contour by rotary swaging by means of a forming machine (10) according to claim 15, comprising the method steps of:arranging, in particular clamping, a workpiece blank (18) on the forming machine (10);producing the cylindrical workpiece with the helical outer contour by moving the feed device (14) in an axial movement (29) along the feed axis (20) and simultaneously carrying out the relative rotational movement (30) between the forming tool arrangement (12) and the feed device (14);wherein the rotary movement (30) is adapted to the axial movement (29) such that the forming cams (72; 72a, 72b) along the helical lines (80, 82) cause plastic deformation of the workpiece blank (18) by radial deflection of the forming tools (46).

17. The forming method according to claim 16, wherein the cylindrical workpiece is produced from a hollow workpiece blank (18), wherein a forming mandrel is arranged within the hollow workpiece blank (18) before producing the cylindrical workpiece with the helical outer contour.

18. A computer program configured for operating a forming machine (10) to carry out the method according to claim 16, wherein a numerical machine controller (34) is provided as the machine controller (34),wherein the computer program for the machine controller (34) comprises control instructions which cause the forming method to be carried out when the computer program is running on the numerical machine controller (34) of the forming machine (10).

19. The forming tool (46) according to claim 4, wherein the cam structure (70) has at least six forming cams arranged equidistant from one another in the longitudinal direction (74).

20. The forming tool (46) according to claim 4, wherein the cam structure (70) has at least twelve forming cams arranged equidistant from one another in the longitudinal direction (74).

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