cold rolling machine

Abstract

The invention relates to a cold rolling machine (10) with two tool pairs (18, 19), each comprising a first rolling bar (20) and a second rolling bar (21) for cold forming a workpiece (11). The rolling bars (20, 21) are movable in opposite directions parallel to a longitudinal direction (L) for forming. Each rolling bar (20, 21) is attached to an associated tool slide (32). Each tool slide (32) can be moved and positioned in the longitudinal direction (L) by means of an associated drive unit (33). The drive unit (33) is controllable by means of a control unit (34). The tool slides (32) can be individually positioned and moved in the longitudinal direction (L). The cold rolling machine (10) has at least three individually movable tool slides (32).To set up the cold rolling machine (10), the tool slides (32) and the attached rolling bars (20), (21) of each tool pair (18, 19) can be moved longitudinally (L) to a defined reference position (R1, R2) in order to obtain the desired geometry of the profile (13) on the formed workpiece (11) during subsequent forming. The reference position (R1, R2) can optionally be corrected during series production of several workpieces (11) of the same type if this is necessary due to external influences, such as thermal effects, tool deviations, or tool wear.

Description

[0001] The invention relates to a cold rolling machine for cold forming a workpiece, in particular a cylindrical or hollow cylindrical section of a workpiece. During the forming process, a profile is produced on the circumference of the workpiece by cold forming, for example, a spur gear parallel to an axis of the workpiece, a helical gear inclined to the axis of the workpiece, or a thread.

[0002] Cold rolling machines and methods for producing such a profile are known, for example from EP 1 286 794 B1 or EP 3 807 023 B1.

[0003] EP 2 976 170 B1 discloses a cold rolling machine with movable tools for forming a pattern, e.g., a thread, on the outer surface of a cylindrical blank. The blank rolls between the tools during machining. The cold rolling machine includes a slide and bearing assembly to support the tools, which are driven by a controlled servo motor. The cold rolling machine can have several sets of tools for producing multiple parts during a single stroke or separate drives to power each tool of a set independently.

[0004] Based on known cold rolling machines, the object of the present invention is to increase the productivity of a cold rolling machine while ensuring high quality and low scrap of formed workpieces.

[0005] This problem is solved by a cold rolling machine with the features of claim 1.

[0006] The cold rolling machine according to the present invention is configured to produce a profile on at least one cylindrical or hollow cylindrical section of a workpiece, or on several workpieces, by means of cold forming. The profile can be a thread or a toothed section. The toothed section can extend parallel to a workpiece axis or inclined obliquely in a circumferential direction around the workpiece axis, thus forming a spur gear or a helical gear. The workpiece's outer surface, or the profile produced thereon, is arranged coaxially with the workpiece axis.

[0007] For cold forming, the cold rolling mill has two or more than two pairs of tools. To distinguish them, the tool pairs can be designated as the first tool pair and the second tool pair, and any further tool pairs can be numbered consecutively. Each tool pair has two rolling bars extending in a longitudinal direction. These rolling bars can be designated as the first rolling bar and the second rolling bar. The first and second rolling bars of a common tool pair are arranged transversely at a distance from each other.

[0008] It should be noted here that the number words in direct combination with a feature (e.g. "first", "second", ...) serve only to distinguish the features and do not represent any restriction with regard to the order or number of the features present.

[0009] Each rolling bar has a rolling profile, with the rolling profiles of the rolling bars of a common tool pair facing each other in the transverse direction. The workpiece can be positioned transversely between the rolling bars of a common tool pair and rotatably about the workpiece axis. For forming, the rolling bars of a common tool pair are pressed transversely against the workpiece's outer surface from opposite sides with their rolling profiles and moved longitudinally in opposite directions relative to each other, whereby the workpiece's outer surface rolls between the rolling profiles and is thereby formed to create the profile.

[0010] The cold rolling machine according to the invention can form two or more workpieces simultaneously with the two tool pairs. For this purpose, it has at least three, and preferably four, independently movable tool slides for moving the rolling bars in the longitudinal direction for two tool pairs. Each additional tool pair can also be assigned one or two independently movable tool slides. Therefore, each tool pair can be assigned one or two of the independently movable tool slides. The tool slides are not mechanically coupled and can each be moved individually in the longitudinal direction via an associated, controllable drive unit. The controllable drive units for the tool slides are controlled by a common control unit and can therefore be moved in a coordinated manner.Each tool slide is assigned exactly one controllable drive unit, so that the cold rolling machine has at least three and preferably four drive units in the case of two tool pairs. Each drive unit can, for example, comprise a controllable electric motor.

[0011] The control unit can be any electrical and / or electronic unit designed to execute a control program. For this purpose, the control unit can, for example, include a microcontroller and / or working memory and / or non-volatile memory.

[0012] The control unit of the cold rolling mill is designed to adjust the rolling bars of the tool pairs so that the two rolling bars of each tool pair assume an individually adjustable reference position relative to each other in the longitudinal direction. The reference position thus describes the relative position of the rolling bars of a common tool pair in the longitudinal direction. For this purpose, the control unit uses the individually movable tool slides and the controllable drive unit assigned to each tool slide. Using the individually movable tool slides, the reference positions, as well as any other desired position, of the two tool pairs can be set independently of each other.

[0013] Referencing or adjustment ensures that the geometry or shape of the profile, viewed circumferentially around the workpiece axis, meets the requirements. In particular, adjustment or referencing reduces or eliminates pitch errors in the manufactured profile, so that the profile corresponds to the desired pitch values ​​or the defined tolerance range. The pitch defines the distance between two adjacent flanks of the profile along the respective pitch circle around the workpiece axis (e.g., in spur gearing), parallel to the workpiece axis (e.g., threads), or perpendicular to the direction of travel of profile teeth (e.g., helical gearing).

[0014] After adjustment or referencing, the workpieces can be formed, thereby producing the profiles on the workpiece outer surfaces. For this purpose, the tool slides are moved longitudinally in a coordinated manner, so that the first rolling bars of the tool pairs move in the opposite direction to the second rolling bars of the tool pairs, and the workpieces roll between a first rolling bar and a second rolling bar of each tool pair, as explained above.

[0015] High productivity is achieved by simultaneously forming two workpieces. The formed workpieces can be identical or different. Compared to two cold rolling machines, each with only one tool pair, the footprint of the cold rolling machine according to the invention is reduced. The pitch of the profile to be produced on the two workpieces can be individually optimized for each tool pair to meet the target specifications. Corrections can be controlled by the control unit if one or both reference positions need to be changed. Mechanically disconnecting and reconnecting a rolling bar to a tool slide is not required. Therefore, the setup times required for such adjustments or referencing are minimal.

[0016] The adjustment or referencing can be automated based on at least one parameter automatically determined or specified by an operator, for example at least one division parameter that characterizes a target value of the division and / or an actual value of the division of a profile.

[0017] By arranging the rolling bars on three or preferably four (or even more than four) tool slides, the transmission of vibrations between the individual rolling bars can be reduced. This means that the vibrations occurring during the forming of a workpiece using one tool pair have less of an impact on the forming of the workpiece using at least one other tool pair, thus reducing vibration-related disadvantages. The influence of thermal length changes can also be reduced and more easily compensated for by individually referencing or adjusting the tool pairs.

[0018] In one embodiment, the first rolling bars of the two tool pairs, or alternatively the second rolling bars of the two tool pairs, can be arranged on a common tool slide. The other rolling bars are then arranged on individual tool slides. This allows the rolling bars of each tool pair to be adjusted or referenced in the longitudinal direction L in order to set the respective reference positions.

[0019] In another embodiment, each rolling bar is arranged on a separate, individual tool slide. This provides an additional degree of freedom in controlling the movement of the tool slides. A further advantage of this arrangement is that mutual influences between the tool pairs (e.g., due to vibrations, thermal expansion, etc.) are not transmitted along a common tool slide, thus achieving a further improvement in decoupling.

[0020] It is preferred that the control unit be configured to move the tool slides longitudinally during the forming of the workpieces in such a way that the first rolling bars move synchronously with each other and that the second rolling bars move synchronously with each other. Synchronous movement means that the movement of each tool slide begins and ends simultaneously – and optionally, that the tool slides have the same speed of movement at all times.

[0021] To shape the workpieces, the rolling bars of each tool pair can also be moved multiple times in opposite directions in the longitudinal direction (multiple strokes), thereby reversing the direction of movement between two strokes.

[0022] It is advantageous if the control unit is set up to move the tool slides in the longitudinal direction during the forming of the workpieces in such a way that all rolling bars are moved by the same distance.

[0023] Preferably, the tool slides are moved during the forming process such that the first rolling bars are moved synchronously without changing their relative position in the longitudinal direction, and the second rolling bars are also moved synchronously without changing their relative position in the longitudinal direction relative to each other. In other words, during the forming process, there is no relative movement of the first rolling bars relative to each other in the longitudinal direction, and no relative movement of the second rolling bars relative to each other in the longitudinal direction.

[0024] If multiple tool slides are available for the first rolling bars, or if multiple tool slides are available for the second rolling bars, the tool slides for the first rolling bars or the tool slides for the second rolling bars are longitudinally spaced apart from each other. This longitudinal space exists between the tool slides that are arranged at the same height when viewed transversely. This longitudinal space decouples the tool slides from each other, specifically preventing them from being mechanically coupled in their movement.

[0025] In one embodiment, the longitudinal distance between two adjacent tool slides can be smaller than the path traveled during the forming process. The path travel is the longitudinal distance between the initial position of a rolled bar before forming and its final position after forming.

[0026] In an advantageous embodiment, the cold rolling mill has a position sensor arrangement. This arrangement comprises several position sensors configured to detect, directly or indirectly, the longitudinal position of each tool slide relative to a machine base of the cold rolling mill and to transmit the corresponding position sensor values ​​to the control unit. The position sensors can be absolute or relative measuring sensors. A position sensor value can directly or indirectly indicate the position of a tool slide relative to the machine base.

[0027] Optionally, the position sensor arrangement can also be configured to detect the position of one or more tool slides in a spatial direction other than the longitudinal direction, for example in the transverse direction, if the tool slide can be moved or positioned in another spatial direction.

[0028] It is also advantageous if the control unit is configured to determine the individual reference position for the assigned tool pair based on at least one division parameter of the profile to be produced or of the profile produced on a workpiece, and to set this position by appropriately controlling at least one drive unit during the adjustment or referencing process. The division parameter can describe a target value and / or an actual value and / or a target-actual deviation of a profile division.

[0029] Advantageous embodiments of the invention will become apparent from the dependent claims, the description, and the drawing. Preferred embodiments of the invention are explained in detail below with reference to the accompanying drawing. The drawing shows: Fig. 1 A schematic, block diagram-like representation of an embodiment of a cold rolling machine with two tool pairs and three tool slides, Fig. 2 a schematic, block diagram-like representation of an embodiment of a cold rolling machine with two tool pairs and four tool slides, Fig. 3 a schematic representation of the tool slides and the two tool pairs during referencing or adjustment, Fig. 4 An exemplary schematic representation of the tool slides and tool pairs during a forming operation of two workpieces, Fig. 5 a schematic representation of an embodiment of a known rolling bar for the tool pairs of the cold rolling machine according to the invention from the Fig. 1-4 and Fig. 6 a perspective view of an exemplary, known workpiece with a profile produced by means of the cold rolling machine according to the invention.

[0030] In the Fig. 1 and Fig. Figure 2 shows different embodiments of a cold rolling machine 10, each in the form of a block diagram. The cold rolling machine 10 is designed to produce a profile 13 by cold forming a workpiece 11, in particular an outer surface 12 of the workpiece 11 ( Fig. 6) The workpiece outer surface 12 is present on a cylindrical or hollow cylindrical section of the workpiece 11. Before forming, the workpiece outer surface 12 extends coaxially to a workpiece axis W.

[0031] The manufactured profile 13 can be a toothed section 14 or, alternatively, a thread. In Fig. Figure 6 shows an exemplary straight tooth as one embodiment of the toothing 14. The teeth of this toothing 14 extend parallel to the workpiece axis W. Alternatively, the toothing 14 can also be a helical tooth, in which case the teeth extend obliquely to the workpiece axis W when viewed circumferentially around the workpiece axis W.

[0032] The cold rolling machine 10 can simultaneously form several workpieces 11, for example, two. For this purpose, the cold rolling machine 10 has several tool pairs, for example, a first tool pair 18 and a second tool pair 19. Each tool pair 18, 19 has a first rolling bar 20 and a second rolling bar 21, the rolling bars 20, 21 extending in a longitudinal direction L. Perpendicular to a longitudinal direction L, and in a transverse direction Q, the first rolling bar 20 and the second rolling bar 21 of a common tool pair 18 or 19 are arranged at a distance from each other.

[0033] In Fig. Figure 5 schematically illustrates an embodiment of a rolled bar that can be used as a first rolled bar 20 and a second rolled bar 21. The rolled bar 20, 21 has a rolled bar profile 22 with a plurality of rolled profile teeth 23, which are arranged at intervals in the longitudinal direction L. Two immediately adjacent rolled profile teeth 23 are each separated from each other by a rolled profile tooth gap 24. Fig. Figure 6 merely shows two of the rolled profile teeth 23 as an example. The rolled bar profile 22 extends longitudinally L along the entire rolled bar 20, 21, as schematically represented by the dashed line and the dash-dotted line.

[0034] At the in Fig. In the embodiment shown in Figure 5, the rolled bar profile 22 has an inlet area 25, a central area 26 adjoining the inlet area 25, and an outlet area 27 adjoining the central area 26. The inlet area 25 is optional and can also be omitted and replaced by a correspondingly longer central area 26.

[0035] In the entry region 25, the tooth height of the rolled profile teeth 23 increases in the transverse direction Q up to the central region 26. In the central region 26, the tooth height of the rolled profile teeth 23 is constant. In the exit region 27, the tooth height of the rolled profile teeth 23 is constant and preferably the same as in the central region 26. While in the central region 26 the tooth tips of the profile teeth 23 are arranged along a common plane E extending in the longitudinal direction L, in the exit region 27 the profile tooth tips of the profile teeth 23 are arranged at a distance from this plane, the distance from this plane E increasing in the exit region 27 the further the rolled profile tooth 23 is from the central region 26 in the longitudinal direction L.

[0036] In the exemplary embodiment, the profile teeth 23 extend perpendicular to the longitudinal direction L in order to accommodate the Fig. Six exemplary straight gear teeth are shown. Alternatively, the rolled profile teeth 23 could also extend obliquely to the longitudinal direction L, for example, if a helical gear is to be produced.

[0037] As also in the Fig. As illustrated in Figures 1-5, each rolling bar 20, 21 can be attached to an associated tool slide 32 by means of a tool carrier 31, for example by means of a screw connection or another detachable connection. The rolling bars 20, 21 are detachably arranged (for example, indirectly or alternatively directly) on the associated tool slide 32 and are arranged relative to the respective tool slide 32.

[0038] The cold rolling machine 10 has several tool slides 32. In the one in Fig. In the embodiment shown in 1, the cold rolling machine 10 has three tool slides 32 and in the embodiment according to Fig. 2 four tool slides 32. Each tool pair 18, 19 is assigned two separate tool slides 32 for the first rolling bar 20 and the second rolling bar 21.

[0039] The tool slides 32 are individually movable in the longitudinal direction L. There is no fixed mechanical motion coupling between the existing tool slides 32. The motion control of the tool slides 32 can be individually defined for each tool slide 32.

[0040] Each tool slide 32 is assigned a separate, individually controllable drive unit 33. Each drive unit 33 can, for example, comprise a controllable electric motor. The control of the drive units 33 for the movement of the respective assigned tool slide 32 in the longitudinal direction L is effected by a control unit 34 of the cold rolling machine 10. The control unit 34 can, for example, be any electrical and / or electronic device configured to execute a control program and may, for example, comprise a microcontroller, working memory, and non-volatile data storage.

[0041] The control unit 34 generates a control signal Ai for each existing drive unit 33. In the case of the Fig. In the embodiment shown in Figure 1, three drive units 33 are provided, so that three individual control signals A1, A2, A3 are generated. The embodiments of the cold rolling machine 10 according to the Fig. 2 and Fig. The 3 have four drive units 33, so that four individual control signals A1, A2, A3, A4 are generated for each drive unit 33. This makes it possible to move each tool slide 32 in the longitudinal direction L relative to a machine base 35 using the control unit 34 and the drive units 33.

[0042] The machine base 35 is in the Fig. 1 and Fig. Figure 2 is shown schematically using a dashed line. The tool slides 32 can, for example, be arranged on the machine base 35 so as to be movable in the longitudinal direction L by means of a rail guide or another suitable guide device.

[0043] In the embodiments illustrated here, the cold rolling machine 10 has a position sensor arrangement 38. The position sensor arrangement 38 is configured to detect the position of each existing tool slide 32 in the longitudinal direction L relative to a common reference system, in particular the machine base 35. Thus, the absolute position of each tool slide can always be determined.

[0044] The position sensor arrangement 38 can have several position sensors 39, each generating a position sensor value Pi (i=1, 2, 3, 4). A separate position sensor 39 can be assigned to each individually movable tool slide 32. The position sensor 39 can be configured as an absolute position sensor or as a relative position sensor. The position sensors 39 can be arranged on an assigned tool slide 32 or the machine base 35, or they can be part of the drive unit 33. For example, motion and / or position detection of the assigned tool slide 32 can be achieved via an encoder of an electric motor in the drive unit 33.

[0045] The in the Fig. 1 and Fig. The arrangement of position sensors 39 shown in Figure 2 of the position sensor arrangement 38 is merely exemplary and greatly simplified. Depending on the number of individually movable tool slides 32, the embodiments illustrated here accordingly have three or four position sensors 39, each of which generates a position sensor value Pi and transmits it to the control unit 34. In the embodiment according to Figure 2, the position sensors 39 are arranged in the position sensor arrangement 38. Fig. 1. Therefore, three position sensor values ​​P1, P2, P3 are provided to the control unit 34, while in the embodiment according to Fig. 2 four position sensor values ​​P1, P2, P3, P4 are provided for the control unit 34.

[0046] The control unit 34 is designed to determine the position and movement of the tool slides 32 in the longitudinal direction L depending on the received position sensor values ​​Pi and to adjust them by means of the control signals Ai.

[0047] The control unit 34 is configured to perform an adjustment or referencing for each existing tool pair 18, 19 and to move the first rolling bar 20 and the second rolling bar 21 of each common tool pair 18, 19 into a defined reference position Ri (i = 1, 2). The reference position Ri is a relative position between the two rolling bars 20, 21 of a common tool pair 18, 19 in the longitudinal direction L. Relative to this reference position Ri, the rolling bars 20, 21 move in the longitudinal direction L by the same distance and, in particular, synchronously and in opposite directions.

[0048] Parallel to the longitudinal direction L, each rolling bar 20, 21 can be moved by means of the associated tool slide 32 either in a forward direction F or in a reverse direction B opposite to the forward direction F. The forward direction F and the reverse direction B each represent a direction of the longitudinal direction L. Starting from the set reference position Ri, for example, the second rolling bar 21 is moved a distance in the forward direction F when the first rolling bar 20 of the same tool pair 18, 19 is moved the same distance in the reverse direction B from the reference position Ri. The same applies to movements with opposite directions (forward direction F or reverse direction B) parallel to the longitudinal direction L.

[0049] Thus, 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 set using the control unit 34 and the drive units 33. The referencing or adjustment of the rolling bars 20, 21 of the two tool pairs 18, 19 is only highly schematically represented in Fig. Figure 3 illustrates this. For example, the tool slides 32 on which the first rolling bars 20 of the respective tool pair 18, 19 are arranged can be moved and positioned. Additionally or alternatively, it would also be possible to move the tool slide 32 or tool slides 32 on which the second rolling bars 21 are arranged.

[0050] The control unit 34 can determine the reference positions R1 and R2 based on the respective position sensor values ​​Pi. By referencing the rolling bars 20 and 21 of a respective tool pair 18 and 19 relative to each other, it is ensured that the desired division of the profile 13 on the workpiece 11 is achieved with the required accuracy. Division errors during the production of the profile 13 are reduced or eliminated.

[0051] Following the referencing, workpieces 11 can then be reshaped to produce the profile 13 ( Fig. 4) The tool slides 32 each perform a movement in the longitudinal direction L, i.e., either in the forward direction F or in the reverse direction B, so that the first rolling bar 20 and the second rolling bar 21 of each tool pair 18, 19 move in opposite directions. In the Fig. In the schematically depicted sequence 4, the first rolling bars 20 are moved in the reverse direction B and the second rolling bars 21 in the forward direction F. The path lengths s that the tool slides 32, and thus the rolling bars 20 and 21, travel are equal.

[0052] During this movement of the rolling bars 20, 21 in forward direction F or backward direction B, a workpiece 11 is rolled between the first rolling bar 20 and the second rolling bar 21 of each tool pair 18, 19 between the opposing rolling bar profiles 22 of the two rolling bars 20, 21, thereby producing the desired profile 13 by cold forming.

[0053] During movement along the respective path length s, the rolling bars 20, 21 can perform a single stroke without reversing direction or several successive strokes with a reversal of direction between successive strokes. The path length s ultimately corresponds to the total distance traveled by a tool slide 32 or the rolling bar 20 or 21 attached to it between a starting position before forming and a final position after forming. When a workpiece 11 has been completely formed, the tool slides 32 or rolling bars 20, 21 can be moved back to their starting positions. New workpieces 11 can then be fed into the cold rolling machine 10 and formed.

[0054] As shown schematically in Fig. As can be seen in Figure 4, the tool slides 32, arranged at the same height in the transverse direction Q, are arranged with a longitudinal distance d from each other. The longitudinal distance d between any two immediately adjacent tool slides 32 can differ, for example, if there are more than two tool pairs and more than four tool slides 32. In the case of the Fig. In the example shown in Figure 5, the two tool slides 32, each carrying the first rolling bar 20, have a longitudinal distance d from each other, and the tool slides 32, each carrying a second rolling bar 21, also have a longitudinal distance d relative to each other. The longitudinal distance d can be kept relatively small to limit the size of the cold rolling machine in the longitudinal direction L and to achieve a compact design. In particular, it can be smaller than the path length s that a tool slide 32 travels when forming a workpiece 11 in the longitudinal direction L. The illustration in Fig. Figure 5 is merely schematic and not to scale. The longitudinal distance d can also be only a fraction of the path length s, for example, a maximum of 50%, 30%, or 15% of the path length s.

[0055] Adjustment or referencing is not required before forming each workpiece 11 with the relevant tool pair 18, 19. In principle, it is sufficient to perform referencing once during the setup of the cold rolling mill for a given workpiece type. This setup referencing can be stored in the control unit 34 and does not need to be repeated when producing the same workpiece again.

[0056] Optionally, the manufactured profiles 13 can be inspected on the workpieces 11, at least on a sample basis, to determine whether the manufactured profile has a geometry within the specified tolerances. If necessary, a correction of the relevant reference position R1 or R2 can be carried out for one or both tool pairs 18, 19 to ensure the quality of the manufactured profiles 13 on the workpiece 11, in particular compliance with the specified tolerances.

[0057] In one embodiment, the control unit 34 can be provided with a division parameter T, which describes a division of a profile 13 to be produced or of a profile 13 that has already been produced. The division parameter T can thus specify a target value for a division and / or an actual value of a division on a profile 13 that has already been produced (directly or indirectly). For example, the division parameter T can describe a target-actual deviation. Based on the division parameter T, the control unit 34 can determine the reference position R1, R2 for the respective tool pair 18, 19 and set it during referencing or adjustment.

[0058] It is understood that division parameters describing an actual value of a manufactured profile 13 on a workpiece 11 are only used to determine the reference position R1 or R2 of the tool pair 18 or 19 with which the profile 13 in question was manufactured. If the division parameter T refers to target values, the same division parameter T can be used for both tool pairs 18 and 19.

[0059] The invention relates to a cold rolling machine 10 with two tool pairs 18, 19, each comprising a first rolling bar 20 and a second rolling bar 21 for cold forming a workpiece 11. The rolling bars 20, 21 are movable in opposite directions parallel to a longitudinal direction L for forming. Each rolling bar 20, 21 is attached to an associated tool slide 32. Each tool slide 32 can be moved and positioned in the longitudinal direction L by means of an associated drive unit 33. The drive unit 33 is controllable by means of a control unit 34. The tool slides 32 can be individually positioned and moved in the longitudinal direction L. The cold rolling machine 10 has at least three individually movable tool slides 32.To set up the cold rolling machine 10, the tool slides 32 and the attached rolling bars 20, 21 of each tool pair 18, 19 can be moved longitudinally L to a defined reference position R1, R2 in order to obtain the desired geometry of the profile 13 on the formed workpiece 11 during subsequent forming. The reference position R1, R2 can optionally be corrected during series production of several workpieces 11 of the same type if this is necessary due to external influences, such as thermal effects, tool deviations from a target tool shape, or tool wear. Reference symbol list: 10 Cold rolling machine 11 Workpiece 12 Workpiece outer surface 13 Profile 14 gear teeth 18 first tool pair 19 second pair of tools 20 first rolling bar 21 second rolling bar 22 Rolled bar profile 23 Rolled profile tooth 24 Rolled profile tooth gap 25 Inlet area 26 Central Area 27 Outlet area 31 tool carriers 32 tool slides 33 Drive unit 34 Control unit 35 machine base 38 Position sensor arrangement 39 Position sensor AI control signal (i=1, 2, 3, 4) B Reverse direction d longitudinal distance Level E F Forward direction L Longitudinal direction Pi position sensor value (i=1, 2, 3, 4) Q transverse direction Ri Reference Position (i=1, 2) s path length T division parameters W workpiece axis

Claims

[1] Cold rolling machine (10) for cold forming a workpiece (11) in order to produce a profile (13) on an outer surface (12) of the workpiece, comprising: - two pairs of tools (18, 19) each with a first rolling bar (20) extending in a longitudinal direction (L) and a second rolling bar (21) extending in a longitudinal direction (L) and arranged at a distance from the first rolling bar (20) in a transverse direction (Q), - at least three independently movable tool slides (32), wherein the rolling bars (20, 21) of a common tool pair (18, 19) are arranged on different tool slides (32), - one controllable drive unit (33) for each existing tool slide (32), which is configured to move the associated tool slide (32) in the longitudinal direction (L), - a control unit (34) configured to control at least two of the drive units (33) such that the first rolling bar (20) and the second rolling bar (21) of each tool pair (18, 19) assume an individually adjustable reference position (R1, R2) relative to each other in the longitudinal direction (L), wherein the control unit (34) is also configured to move all tool slides (32) in the longitudinal direction (L) by means of the drive units (33) after setting the reference positions (R1, R2), so that the first rolling bars (20) move in the longitudinal direction (L) in the opposite direction to the second rolling bars (21) in order to form the workpieces (11) between the rolling bars (20, 21). [2] Cold rolling machine according to claim 1, wherein each rolling bar (20, 21) is arranged on a separate tool slide (32). [3] Cold rolling machine according to claim 1, wherein the first rolling bars (20) or the second rolling bars (21) of the existing tool pairs (18, 19) are arranged on a common tool slide (32). [4] Cold rolling machine according to one of the preceding claims, wherein the control unit (34) is configured to move the tool slides (32) in the longitudinal direction (L) during the forming of the workpieces (11) such that the first rolling bars (20) are moved synchronously with each other and that the second rolling bars (21) are moved synchronously with each other. [5] Cold rolling machine according to one of the preceding claims, wherein the control unit (34) is configured to move the tool slides (32) in the longitudinal direction (L) during the forming of the workpieces (11) such that all rolling bars (20, 21) are moved by the same distance (s). [6] Cold rolling machine according to one of the preceding claims, wherein the tool slides (32) for the first rolling bars (20) and / or the tool slides (32) for the second rolling bars (21) are arranged in the longitudinal direction (L) with a longitudinal distance (d) from each other. [7] Cold rolling machine according to claim 5 and claim 6, wherein the longitudinal distance (d) is smaller than the distance (s) traveled by the tool slide during the forming process. [8] Cold rolling machine according to one of the preceding claims, further comprising a position sensor arrangement (38) which is configured to detect the position of each tool slide (32) in the longitudinal direction (L) and to transmit corresponding position sensor values ​​(P1, P2, P3, P4) to the control unit (34). [9] Cold rolling machine according to one of the preceding claims, wherein the control unit (34) is also configured to determine and set the individual reference position (R1, R2) for each tool pair (18, 19) based on at least one predetermined division parameter (T) of the profile (13). [10] Cold rolling machine according to claim 9, wherein the division parameter (T) of the profile describes a target value and / or an actual value and / or a target-actual deviation of a division.

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