COLD FORMING MACHINE

Abstract

The present disclosure refers to a cold forming machine having two tool pairs that include a first cold forming rack and a second cold forming rack for cold forming of a workpiece respectively. The cold forming racks are movable parallel to a longitudinal direction during deformation. Each cold forming rack is attached to an assigned tool slide. Each tool slide can be moved and positioned in a longitudinal direction by means of an assigned drive unit. The drive unit is controllable by means of a control unit. The control slides can be individually positioned and moved in the longitudinal direction. Cold forming machine comprises at least three individually movable tool slides. For setup of cold forming machine, the tool slides and the cold forming racks of each tool pair attached thereon can be brought into a defined reference position in order to obtain the desired geometry of the profile on the deformed workpiece during the following deformation. The reference position can be corrected optionally during a series production of multiple workpieces of the same type, if this is necessary due to external influences, such as thermal influences, tool variations from a desired tool shape or tool wear.

Claims

1. A cold forming machine for cold forming of a workpiece in order to create a profile on a workpiece outer surface comprising: two tool pairs each having one first cold forming rack extending in a longitudinal direction and one second cold forming rack extending in the longitudinal direction arranged with distance to the one first cold forming rack in a transverse direction, at least three tool slides that can be moved independently from one another, wherein the one first cold forming rack and the one second cold forming rack racks of a common tool pair of the two tool pairs are arranged on different tool slides of the at least three tool slides, a controllable drive unit for each tool slide of the at least three tool slides that is configured to move an assigned tool slide of the at least three tool slides in the longitudinal direction, a control unit that is configured to control the controllable drive unit of at least two of the at least three tool slides in a manner so that the one first cold forming rack and the one second cold forming rack of each of the two tool pairs take an individually adjustable reference position relative to one another in the longitudinal direction, wherein the control unit is also configured to move the at least three tool slides by the controllable drive unit of each tool slide of the at least three tool slides in the longitudinal direction after adjustment of the individually adjustable reference position, so that the one first cold forming rack first cold forming racks moves opposite to the one second cold forming racks in the longitudinal direction in order to thereby deform the workpieces between the one first cold forming rack and the one second cold forming rack.

2. The cold forming machine according to claim 1 wherein the one first cold forming rack and the one second cold forming rack of the two tool pairs is arranged on a separate tool slide of the at least three tool slides.)

3. The cold forming machine according to claim 1, wherein the one first cold forming racks or the one second cold forming racks of each of the two tool pairs are arranged on a common tool slide of the at least three tool slides.

4. The cold forming machine according to claim 1, wherein the control unit is configured to move the at least three tool slides during deformation of the workpieces in the longitudinal direction, so that the one first cold forming racks of each of the two tool pairs is temporally synchronously moved with one another and that the one second cold forming racks of each of the two tool pairs are temporally synchronously moved with one another.

5. The cold forming machine according to claim 1, wherein the control unit is configured to move the at least three tool slides during deformation of the workpieces in the longitudinal direction, so that the one first cold forming rack and the one second cold forming rack of each of the two tool pairs are moved about a same path length.

6. The cold forming machine according to claim 1, wherein the at least three tool slides for the one first cold forming racks of each of the two tool pairs and/or the at least three tool slides for the one second cold forming racks of each of the two tool pairs are arranged with a longitudinal distance (d) in the longitudinal direction relative to one another.)

7. The cold forming machine according to claim 6, wherein the control unit is configured to move the at least three tool slides during deformation of the workpiece in the longitudinal direction, so that the one first cold forming rack and the one second cold forming rack of each of the two tool pairs are moved about a same path length, and wherein the longitudinal distance is smaller than the path lengths traveled by the at least three tool slides during deformation.)

8. The cold forming machine according to claim 1, further comprising a position sensor arrangement that is configured to detect a position of each the at least three tool slides in the longitudinal direction and to transmit respective position sensor values to the control unit.

9. The forming machine according to claim 1, wherein the control unit is additionally configured to determine and adjust the individually adjustable reference position for each of the two tool pairs based on a preset pitch parameter of the profile.

10. The cold forming machine according to claim 9, wherein the pitch parameter(T) of the profile describes a set point value and/or an actual value and/or a deviation between a set point value and an actual value of a pitch.

11. The cold forming machine according to claim 2, wherein the control unit is configured to move the at least three tool slides during deformation of the workpiece in the longitudinal direction, so that the one first cold forming rack of each of the two tool pairs is temporally synchronously moved with one another and that the one second cold forming rack of each of the two tool pairs are temporally synchronously moved with one another.

12. The cold forming machine according to claim 3, wherein the control unit is configured to move the at least three tool slides during deformation of the workpiece in the longitudinal direction, so that the one first cold forming rack of each of the two tool pairs is temporally synchronously moved with one another and that the one second cold forming rack of each of the two tool pairs are temporally synchronously moved with one another.

13. The cold forming machine according to claim 11, wherein the control unit is configured to move the at least three tool slides during deformation of the workpiece in the longitudinal direction, so that the one first cold forming rack and the one second cold forming rack of each of the two tool pairs are moved about a same path length.

14. The cold forming machine according to claim 12, wherein the control unit is configured to move the at least three tool slides during deformation of the workpiece in the longitudinal direction, so that the one first cold forming rack and the one second cold forming rack of each of the two tool pairs are moved about a same path length.

15. The cold forming machine according to claim 13, wherein the at least three tool slides for the one first cold forming rack of each of the two tool pairs and/or the at least three tool slides for the one second cold forming rack of each of the two tool pairs are arranged with a longitudinal distance in the longitudinal direction relative to one another.

16. The cold forming machine according to claim 14, wherein the at least three tool slides for the one first cold forming rack of each of the two tool pairs and/or the at least three tool slides for the one second cold forming rack of each of the two tool pairs are arranged with a longitudinal distance in the longitudinal direction relative to one another.

17. The cold forming machine according to claim 16, wherein the control unit is configured to move the at least three tool slides during deformation of the workpiece in the longitudinal direction, so that the one first cold forming rack and the one second cold forming rack of each of the two tool pairs are moved about a same path length and wherein the longitudinal distance is smaller than the path length traveled by the at least three tool slides during deformation.

18. The cold forming machine according to claim 17, further comprising a position sensor arrangement that is configured to detect a position of each the at least three tool slides in the longitudinal direction and to transmit respective position sensor values to the control unit.

19. The cold forming machine according to claim 18, wherein the control unit is additionally configured to determine and adjust the individually adjustable reference position for each of the two tool pairs based on a preset pitch parameter of the profile.

20. The cold forming machine according to claim 19, wherein the pitch parameter of the profile describes a set point value and/or an actual value and/or a deviation between a set point value and an actual value of a pitch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Advantageous embodiments of the present disclosure are derived from the dependent claims, the description and the drawing. In the following, preferred embodiments of the present disclosure are described in detail with reference to the attached drawing. The drawing shows:

[0030] FIG. 1 a schematic block diagram-like illustration of an embodiment of a cold forming machine having two tool pairs and three tool slides,

[0031] FIG. 2 a schematic block diagram-like illustration of an embodiment of a cold forming machine having two tool pairs and four tool slides,

[0032] FIG. 3 a schematic illustration of the tool slides and the two tool pairs during referencing or adjustment,

[0033] FIG. 4 an exemplary schematic illustration of the tool slides and the tool pairs during a deformation of two workpieces,

[0034] FIG. 5 a schematic illustration of an embodiment of a cold forming rack for the tool pairs of FIGS. 1 to 4, and

[0035] FIG. 6 a perspective illustration of an exemplary workpiece having a profile produced thereon by means of the cold forming machine.

DETAILED DESCRIPTION

[0036] In FIGS. 1 and 2 different embodiments of a cold forming machine 10 are illustrated in the type of a block diagram. The cold forming machine 10 is configured to produce a profile 13 on a workpiece 11, particularly a workpiece outer surface 12 of the workpiece 11 by means of cold forming (FIG. 6). The workpiece outer surface 12 is present on a cylindrical or hollow cylindrical section of the workpiece 11. Prior to deformation, the workpiece outer surface 12 extends coaxially to a workpiece axis W.

[0037] The produced profile 13 can be a toothing 14 or alternatively a thread. In FIG. 6 a spur toothing is illustrated by way of example as an embodiment of toothing 14. The teeth of this toothing extend parallel to the workpiece axis W. Alternatively, the toothing 14 can also be a helical toothing, wherein the teeth then extend obliquely relative to the workpiece axis W with view in circumferential direction around the workpiece axis W.

[0038] By means of the cold forming machine 10, concurrently multiple workpieces 11, for example two workpieces 11, can be deformed. For this purpose, the cold forming machine 10 comprises multiple tool pairs, according to the example a first tool pair 18 and a second tool pair 19. Each tool pair 18, 19 has respectively one first cold forming rack 20 and one second cold forming rack 21, wherein the cold forming racks 20, 21 extend in a longitudinal direction L. Orthogonal to the longitudinal direction L, in a transverse direction Q, the first cold forming rack 20 and the second cold forming rack 21 of a common tool pair 18, 19 are arranged with distance to one another.

[0039] In FIG. 5 an embodiment of a cold forming rack is schematically illustrated that can be used as first cold forming rack 20 and a second cold forming rack 21. The cold forming rack 20, 21 has a cold forming rack profile 22 having a multiplicity of cold forming profile teeth 23 arranged with distance to one another in longitudinal direction L. Two directly adjacent cold forming teeth 23 are separated from one another by a cold forming tooth gap 24. In FIG. 6, by way of example, only two of the cold forming profile teeth 23 are illustrated schematically. The cold forming rack profile 22 extends in longitudinal direction L along the entire cold forming rack 20, 21 as schematically illustrated by way of the dashed line and the dash-dotted line.

[0040] In the embodiment illustrated in FIG. 5 the cold forming rack profile 22 comprises a run-in section 25, a central section 26 adjoining the run-in section 25 and a run-out section 27 adjoining the central section 26. The run-in section 25 is optional and can also be omitted and replaced by a respectively longer central section 26.

[0041] In the run-in section 25 the tooth height of the cold forming profile teeth 23 increases with view in transverse direction Q toward the central section 26. In the central section 26 the tooth height of the cold forming profile teeth 23 is constant. In the run-out section 27, the tooth height of the cold forming profile teeth 23 is constant and preferably as high as in the central section 26. While the tooth heads of the profile teeth 23 in the central section 26 are arranged along a common plane E extending in longitudinal direction L, the profile tooth heads of the profile teeth 23 are arranged with distance to this plane in the run-out section, whereby the distance from this plane E increases in the run-out section 27, the farther the cold forming profile tooth 23 is distanced from the central section 26 in longitudinal direction L.

[0042] In the embodiment the cold forming profile teeth 23 extend orthogonal to the longitudinal direction L in order to create the spur toothing illustrated by way of example in FIG. 6. Alternatively, the cold forming profile teeth 23 can also extend obliquely relative to the longitudinal direction L, for example if helical toothing shall be produced.

[0043] As additionally illustrated in FIGS. 1 to 5, each cold forming rack 20, 21 can be attached to an assigned tool slide 32 by means of a tool carrier 31, for example by means of a screw connection or another releasable connection. The cold forming racks 20, 21 are (according to the example indirectly or alternatively directly) releasably arranged on an assigned tool slide 32 and are arranged immovably relative to the respective tool slide 32.

[0044] The cold forming machine 10 has multiple tool slides 32. In the embodiment illustrated in FIG. 1 the cold forming machine 10 has three tool slides 32 and in the embodiment according to FIG. 2, four tool slides 32. Each tool pair 18, 19, two separate tool slides 32 for the first cold forming rack 20 and the second cold forming rack 21 are assigned.

[0045] The tool slides 32 are individually movable in longitudinal direction. A rigid mechanical coupling between the present tool slides 32 does not exist. The movement control of the tool slides 32 can be individually set for each tool slide 32.

[0046] A separate individually controllable drive unit 33 is assigned to each tool slide 32. Each drive unit 33 can comprise a controllable electric motor, for example. The control of the drive units 33 for movement of the respectively assigned tool slide 32 in longitudinal direction L is carried out by means of a control unit 34 of the cold forming machine 10. For example, control unit 34 can be any electrical and/or electronic device configured for carrying out a control program and can, for example, comprise a micro-controller, a random access memory and a non-volatile data memory.

[0047] The control unit 34 creates a control signal Ai for each present drive unit 33. In the embodiment illustrated in FIG. 1, three drive units 33 are present, so that three individual control signals A1, A2, A3 are created. The embodiments of the cold forming machine 10 according to FIGS. 2 and 3 have four drive units 33, so that four individual control signals A1, A2, A3, A4 for each present drive unit 33 are created respectively. In doing so, it is possible to move each tool slide 32 in longitudinal direction L relative to a machine basis 35 by using control unit 34 and drive units 33.

[0048] The machine basis 35 is only schematically illustrated in FIGS. 1 and 2 by means of a dashed line. For example, the tool slides 32 can be arranged movably in longitudinal direction L on the machine basis 35 by means of a suitable rail guide or another suitable guide device.

[0049] In the embodiments illustrated here, cold forming machine 10 comprises a position sensor arrangement 38. The position sensor arrangement 38 is configured to detect the position of each present tool slide 32 in longitudinal direction L relative to a common reference system, for example the machine basis 35. In doing so, the absolute position of each tool slide can be determined.

[0050] The position sensor arrangement 38 can comprise multiple position sensors 39 that create one position sensor value Pi (i=1, 2, 3, 4) respectively. One separate position sensor 39 can be assigned to each individually movable tool slide 32. The position sensor 39 can be configured as absolute measurement position sensor or as relative measurement position sensor. The position sensors 39 can be arranged on an assigned tool slide 32 or on the machine basis 35 or can be part of the drive unit 33. For example, by means of an encoder of the electric motor of the drive unit 33, a movement and/or position determination of the assigned tool slide 32 can be realized.

[0051] The arrangement of the position sensors 39 of the position sensor arrangement 38 illustrated in FIGS. 1 and 2 is only exemplary and highly simplified. Depending on the number of individually movable tool slides 32 in the embodiments illustrated here, three or four position sensors 39 are present that create one position sensor value Pi respectively and transmit the latter to the control unit 34. In the embodiment according to FIG. 1, three position sensor values P1, P2, P3 are provided to control unit 34, whereas in the embodiment according to FIG. 2, four position sensor values P1, P2, P3, P4 are provided for control unit 34.

[0052] The control unit 34 is configured to determine the position and movement of the tool slides 32 in longitudinal direction L, depending on the received position sensor values Pi and to control the position and movement by means of control signals Ai.

[0053] The control unit 34 is configured to carry out an adjustment or referencing for each present tool pair 18, 19 and to bring the first cold forming rack 20 and the second cold forming rack 21 of each common tool pair 18, 19 in a defined reference position Ri (i=1, 2). The reference position Ri is a relative position between the two cold forming racks 20, 21 of a common tool pair 18, 19 in longitudinal direction L. Relative to this reference position Ri, the cold forming racks 20, 21 move in longitudinal direction L about the same distance respectively and particularly synchronously and thereby opposite to one another.

[0054] Parallel to the longitudinal direction L each cold forming rack 20, 21 can be moved by means of the assigned tool slide 32 either in a forward direction F or in a backward direction B opposite to the forward direction F. The forward direction F and the backward direction B are one sense of direction of the longitudinal direction L respectively, so-to-speak. Starting from the adjusted reference position Ri, the second cold forming rack 21 is moved about a distance in forward direction F, for example if the first cold forming rack 20 of the same tool pair 18, 19 is moved about the same distance in backward direction B starting from the reference position Ri. The same applies also for movements with opposite sense of direction (forward direction F or backward direction B) parallel to the longitudinal direction L respectively.

[0055] Thus, by means of control unit 34 using the drive units 33, the respective reference position R1 for the first tool pair 18 and the reference position R2 for the second tool pair 19 can be individually adjusted. The referencing or adjustment of cold forming racks 20, 21 of the two tool pairs 18, 19 is only highly schematically illustrated in FIG. 3. For example, for this purpose the tool slides 32 can be moved and positioned respectively on which the first cold forming racks 20 of the respective tool pairs 18, 19 are arranged. Additionally or alternatively, it would also be possible to move the tool slide 32 or the tool slides 32 on which the second cold forming racks 21 are arranged.

[0056] The control unit 34 can determine the reference positions R1, R2 based on the respectively detected position sensor values Pi. Due to the referencing of cold forming racks 20, 21 of a respective tool pair 18 or 19 relative to one another, it is guaranteed that the desired pitch of the profile 13 on the workpiece 11 is achieved with the required accuracy. Pitch errors during manufacturing of the profile 13 are reduced or eliminated.

[0057] Following the referencing, workpieces 11 can be deformed in order to create the profile 13 respectively (FIG. 4). Thereby the tool slides 32 carry out a movement in longitudinal direction L respectively, that is either in forward direction F or in backward direction B, so that the first cold forming rack 20 and the second cold forming rack 21 of each tool pair 18, 19 move oppositely. During the progress schematically illustrated in FIG. 4 the first cold forming racks 20 are moved in backward direction B and the second cold forming racks 21 are moved in forward direction F. The path length s that the tool slides 32 and thus the cold forming racks 20, 21 travel thereby have equal lengths.

[0058] During this movement of the cold forming racks 20, 21 in forward direction F or backward direction B, a workpiece 11 between first cold forming rack 20 and second cold forming rack 21 of each tool pair 18, 19 rolls on the facing cold forming rack profiles 22 of the two cold forming racks 20, 21 and thereby the desired profile 13 is produced by means of cold forming.

[0059] During the movement along the respective path length s cold forming racks 20, 21 can carry out one single stroke without changing direction or multiple subsequent strokes thereby changing direction between two subsequent strokes. The path length s thereby finally corresponds to the total path that a tool slide 32or the cold forming racks 20 or 21 attached theretotravel between an initial position prior to deformation and an end position after deformation. If a workpiece 11 is entirely deformed, the tool slides 32 or cold forming racks 20, 21 can be moved into the initial position again. New workpieces 11 can be supplied to cold forming machine 10 and can be deformed.

[0060] As schematically apparent from FIG. 4, tool slides 32 arranged on the same level in transverse direction Q are arranged with longitudinal distance d relative to one another. Thereby the longitudinal distance d between two directly adjacent tool slides 32 may be different, for example if more than two tool pairs and more than four tool slides 32 are present. In the example illustrated in FIG. 5 the two tool slides 32 carrying the first cold forming rack 20 respectively have a longitudinal distance d from one another and the tool slides 32 carrying the second cold forming racks 21 also have a longitudinal distance d relative to one another. The longitudinal distance d can be relatively small in order to limit the size of the cold forming machine in longitudinal direction L and to achieve a compact configuration. Particularly, it can be shorter than the total path length s that the tool slide 32 traveled during deformation of a workpiece 11 in longitudinal direction L. The illustration in FIG. 5 is thereby only schematic and not drawn to scale. The longitudinal distance d can also be only a fraction of the path length s, for example at most 50% or at most 30% or at most 15% of the path length s.

[0061] The adjustment or referencing is not required prior to deformation of each workpiece 11 with respective tool pair 18, 19. In principle, it is sufficient to carry out the referencing one time during setup of the cold forming machine for a type of workpiece to be deformed. This referencing during setup can be stored in the control unit 34 and does not have to be repeated when this type of workpiece shall be manufactured again.

[0062] As an option it is possible to check the profiles 13 produced on the workpieces 11, at least based on random selection, in order to determine whether the produced profile has a geometry within the predefined tolerances. If necessary, a correction of the respective reference position R1 or R2 can be carried out for one or both tool pairs 18, 19, in order to guarantee the quality of the profiles 13 created on the workpiece 11, particularly the compliance with the preset tolerances.

[0063] In an embodiment a pitch parameter T can be provided to control unit 34, wherein pitch parameter T describes a pitch of a profile 13 to be produced or a pitch of an already produced profile 13. Thus, the pitch parameter T can (directly or indirectly) indicate a set point value for the pitch and/or an actual value for the pitch on an already produced profile 13. For example, pitch parameter T can describe a deviation between a set point value and an actual value. Based on pitch parameter T, control unit 34 can determine the reference positions R1, R2 for the respective tool pair 18, 19 and can adjust the latter during referencing or adjustment.

[0064] It is clear that the pitch parameters that describe an actual value of a profile 13 produced on a workpiece 11 are only used for the determination of the reference position R1 or R2 of the concerned tool pair 18 or 19 with which the respective profile 13 has been created. If pitch parameter T refers to set point values, the same pitch parameter T can be used for both tool pairs 18, 19.

[0065] The present disclosure refers to a cold forming machine 10 having two tool pairs 18, 19 that comprise a first cold forming rack 20 and a second cold forming rack 21 for cold forming of a workpiece 11 respectively. The cold forming racks 20, 21 are movable parallel to a longitudinal direction L during deformation. Each cold forming rack 20, 21 is attached to an assigned tool slide 32. Each tool slide 32 can be moved and positioned in longitudinal direction L by means of an assigned drive unit 33. The drive unit 33 is controllable by means of a control unit 34. The control slides 32 can be individually positioned and moved in longitudinal direction L. Cold forming machine 10 comprises at least three individually movable tool slides 32. For setup of cold forming machine 10, the tool slides 32 and the cold forming racks 20, 21 of each tool pair 18, 19 attached thereon can be brought into a defined reference position R1, R2 in order to obtain the desired geometry of the profile 13 on the deformed workpiece 11 during the following deformation. The reference position R1, R2 can be corrected optionally during a series production of multiple workpieces 11 of the same type, if this is necessary due to external influences, such as thermal influences, tool variations from a desired tool shape or tool wear.

LIST OF REFERENCE SIGNS

[0066] 10 cold forming machine [0067] 11 workpiece [0068] 12 workpiece outer surface [0069] 13 profile [0070] 14 toothing [0071] 18 first tool pair [0072] 19 second tool pair [0073] 20 first cold forming rack [0074] 21 second cold forming rack [0075] 22 cold forming rack profile [0076] 23 cold forming profile tooth [0077] 24 cold forming profile tooth gap [0078] 25 run-in section [0079] 26 central section [0080] 27 run-out section [0081] 31 tool holder [0082] 32 tool slide [0083] 33 drive unit [0084] 34 control unit [0085] 35 machine basis [0086] 38 position sensor arrangement [0087] 39 position sensor [0088] Ai control signal (i=1, 2, 3, 4) [0089] B backward direction [0090] d longitudinal distance [0091] E plane [0092] F forward direction [0093] L longitudinal direction [0094] Pi position sensor value (i=1, 2, 3, 4) [0095] Q transverse direction [0096] Ri reference position (i=1, 2) [0097] S path length [0098] T pitch parameter [0099] W workpiece axis