Forming tool, forming device and method for producing a toothing on a workpiece

Abstract

The invention relates to a forming tool (32) for producing a toothing (21) on a workpiece (22). The forming tool (32) has a forming profile (41) with a plurality of profile teeth (42) that extend parallel to one another and are arranged adjacent to one another in a working direction (W). In a tool transverse direction (Q), perpendicular to the working direction (W), the profile teeth (42) merge into a front side surface (49) along a front profile edge (50). The forming profile (41) has two directly or indirectly adjoining profile sections (P1, P2) in the working direction (W). In a first profile section (P1), the front profile edge (50) has a first edge section (50a) with a first edge width (b1) and, in a second profile section (P2), a second edge section (50b) with a second edge width (b2). The second edge width (b2) is smaller than the first edge width (b1).The second edge section (50b) is, so to speak, sharper-edged than the first edge section (50a). The first edge section (50a) is designed such that, during a feed or relative movement transverse to the profile edge (50), with the forming profile (41) engaging the material of the workpiece (22), no chips are removed from the workpiece (22).

Description

[0001] The invention relates to a forming tool that is designed to produce a toothing on a workpiece, in particular on a hollow, rotationally symmetrical workpiece part, and can be used for this purpose. The forming tool can be used in a forming device. A method for producing a toothing on a workpiece can be carried out using the forming tool. The toothing is produced by forming, for example, cold or hot forming, and is carried out entirely without material removal.

[0002] DE 10 2017 116 895 A1 discloses a method and a forming device designed for producing gear teeth on a cylindrical, and in particular a hollow-cylindrical, workpiece. The forming tools used for this purpose engage with the workpiece with their forming profiles and perform several rolling movements, with the direction of the rolling movement being reversed between two consecutive rolling movements. An axial movement along the longitudinal axis of the cylindrical workpiece can be superimposed on the rolling movements.

[0003] This process has proven successful. For special workpiece shapes, the previously used forming tool may result in incomplete forming of the gear to be produced. This occurs, for example, with workpieces where an axial end of the workpiece part on which the gear is to be produced is adjoined by another, particularly larger, workpiece part. Between these workpiece parts, there is often a groove, a recess, an undercut, or another form that is deeper than the gear to be produced.

[0004] It can therefore be considered an object of the present invention to provide an improved forming tool, an improved forming device and an improved forming method in order to ensure the quality of a toothing produced on the workpiece for different workpiece shapes.

[0005] This object is achieved by a forming tool having the features of patent claim 1. Such a forming tool can be used in a forming device according to the invention and in a method according to the invention.

[0006] The forming tool according to the present invention is designed to produce a toothing on a workpiece by forming the workpiece, for example, by hot forming or cold forming. The forming tool is not designed or intended to remove material from the workpiece. The toothing is produced on a part of the workpiece that is rotationally symmetrical with respect to a workpiece axis, for example, a workpiece part that is cylindrical or hollow-cylindrical at least in sections along a workpiece axis. The toothing can be produced parallel to the workpiece axis or at an angle to the workpiece axis around the circumference of the workpiece part.

[0007] The forming tool has a forming profile that allows the forming tool to engage with the workpiece. The geometry of the forming profile is adapted to the geometry of the gearing to be produced on the workpiece. Several profile teeth are arranged adjacent to one another on the forming profile in one working direction. The profile teeth are aligned parallel to each other. Two directly adjacent profile teeth are spaced apart by a tooth gap.

[0008] A tool cross direction is oriented perpendicular to the working direction. The profile teeth can extend parallel to the tool cross direction and thus perpendicular to the working direction, or at an angle to the tool cross direction and inclined to the working direction.

[0009] The forming profile has a first profile section and a second profile section. The two profile sections are arranged directly adjacent to one another in the working direction or indirectly via a transition area between them.

[0010] The forming tool is configured to perform a forward movement relative to the workpiece, parallel to the transverse direction of the tool, when the forming profile in the first profile section is in engagement with the workpiece material. The forming tool has a forward-facing front side surface. Preferably, the front side surface of the forming tool is always out of engagement with the workpiece material during the production of the gear teeth. The front side surface can, for example, be oriented at right angles to the transverse direction of the tool.

[0011] Between the front side surface and the forming profile, the forming tool has a front profile edge. The front profile edge has a different geometry or shape in the first profile section than in the second profile section. The profile edge has a first edge section in the first profile section and a second edge section in the second profile section.

[0012] The first edge section has a geometry or shape that allows a relative movement of the forming tool relative to the workpiece and parallel to the transverse tool direction with simultaneous engagement of the forming profile in the material of the workpiece, without removing material from the workpiece and / or without forming a chip. Material removal that is not technically completely avoidable and insignificant for the forming result is permissible. This can occur, for example, due to friction between the forming tool and the workpiece during the relative movement in the transverse tool direction. Insignificant material removal is understood in particular to mean material removal whose volume is less than 1-2% compared to the volume of material on the workpiece displaced by forming during the relative movement in the transverse tool direction.

[0013] For example, at least one chamfer and / or at least one fillet is present on the first edge portion of the profile edge. The first edge portion is thus sufficiently blunt to completely prevent material removal during the relative movement between the forming tool and the workpiece in the transverse direction of the tool, or at most to allow it to a negligible extent.

[0014] The profile edge has an edge width between the front side surface and the tooth tips of the profile teeth. The edge width is defined as the length of the front profile edge along its outer surface in a cross-sectional plane perpendicular to the working direction. This length, which determines the edge width, extends from the side surface to a transition point at an adjacent tooth tip of a profile tooth in the transverse direction of the tool, to which a tip tangent is applied. The tip tangent extends in the cross-sectional plane, i.e., perpendicular to the working direction, with the cross-sectional plane passing through the center of the profile tooth at the transition point.

[0015] The head tangent, together with the working direction, can span a head plane if the forming tool is a rolling bar or a flat die. The head tangent, together with the working direction, can span a virtual head surface if the forming tool is a rotating roller or roll.

[0016] In the forming tool according to the invention, a first edge width in the first edge section of the front profile edge is greater than a second edge width in the second edge section of the front profile edge. While the first edge section has a blunt edge contour, so to speak, the second edge section has a sharper edge. In one embodiment, the second edge section has an edge shape that is as rectangular as possible—i.e., essentially without chamfers or roundings—insofar as this edge shape can be technically produced.

[0017] The front profile edge has an edge height in a vertical direction, with the vertical direction being oriented at right angles to the working direction and at right angles to the tool transverse direction. The edge height is the distance in the vertical direction between the transition of the profile edge into the front side surface and the transition point between the tip tangent and tooth tip of the profile tooth in the cross-sectional plane through the transition point. Preferably, a first edge height in the first edge section of the front profile edge is greater than a second edge height in the second edge section of the front profile edge. In particular, the first edge height is at least as great as the height or depth of the toothing to be produced on the workpiece.

[0018] In the second profile section, the end faces of the profile teeth can extend essentially up to the tooth tip at right angles to the transverse direction of the tool.

[0019] The inventive design of the forming tool can be characterized as follows, alternatively or in addition to the above description: A virtual plane that is applied to the front side surface of the forming tool has a greater distance in the first profile section in the transverse direction of the tool from a point on the adjacent profile tooth at which the profile tooth has its maximum height in the vertical direction (the forming profile has the complete profile height or profile depth there) than in the second edge section.

[0020] As explained, the front profile edge in the first edge section can have at least one chamfer and / or at least one fillet. An existing fillet can have a constant curvature or a constant radius, or alternatively, a changing curvature or a changing radius. Between the transition point and the front side surface, there can be a chamfer that runs straight in a cross-sectional plane perpendicular to the working direction. There can also be several chamfers that run straight in sections in this cross-sectional plane. It is also possible to provide one or more fillets or radii on the cross-sectional contour of the first edge section in addition to one or more chamfers.

[0021] In contrast, the second section is preferably designed without a chamfer and without rounding - as far as technically feasible.

[0022] It is also preferred if the forming profile has an exit region and a central region adjoining it in the working direction. Optionally, an entry region can be located on the side of the central region opposite the exit region. The depth of engagement of the forming profile into the workpiece material can vary in the existing regions. For example, the depth of engagement can decrease in the exit region away from the central region and, if present, increase in the entry region toward the central region.

[0023] In such a configuration, the outlet region can be located in the second profile section. The inlet region can be located in the first profile section. At least a portion of the central region is located in the first profile section. A further portion of the central region is preferably located in the second profile section.

[0024] The forming tool can be a flat-jaw tool designed to be moved linearly in the working direction during the forming of the workpiece. Alternatively, the forming tool can also be a rotatable roller tool. The roller tool is designed to be rotated about a roller axis during the forming of the workpiece. In this case, the working direction is a circumferential direction around the roller axis.

[0025] If tip tangents are applied to the profile teeth of a flat-jaw tool in one of the existing areas (in the central area, the run-out area, or the inlet area), the tip tangents are arranged in a common plane. In the central area, such a plane is defined by the working direction and the tool's transverse direction. In the inlet and run-out areas, such a plane is inclined relative to the working direction.

[0026] If several head tangents are applied to the profile teeth of a roll tool, at least in the central area, these head tangents are located in a virtual common head surface around the roll axis. In an optionally provided inlet and / or outlet area, the distance of the head tangents from the roll axis can decrease from the central area in the working direction or circumferential direction around the roll axis.

[0027] Viewed in the working direction, the profile tips outside the front profile edge can run parallel to the transverse tool direction or inclined to the transverse tool direction, in particular, starting from the front profile edge, inclined downwards relative to the transverse tool direction when viewed in the transverse tool direction. The inclination can be different in the first profile section than in the second profile section. In particular, the inclination relative to the transverse tool direction is smaller in the second profile section than in the first profile section. The angle of inclination is determined in particular between the tip tangent applied to the tooth tip outside the front profile edge and the transverse tool direction.

[0028] A forming device according to the present invention comprises a first tool holder and a second tool holder, on each of which a forming tool according to any one of the preceding embodiments is arranged. The forming tools of the forming device are preferably designed identically, but can also be slightly different, for example, if a gearing with an odd number of teeth is to be produced. They can be a flat-jaw tool or a roller tool. The forming device also has a holding device for the workpiece to be formed, wherein the part of the workpiece to be provided with the gearing is arranged between the two forming tools so as to be rotatable about a workpiece axis.Existing forming profiles engaging the workpiece from opposite sides of the workpiece's longitudinal axis can be formed by inducing movement of the forming tools in the working direction to produce the toothing. The distance of the forming tools from the workpiece axis is preferably adjustable using the tool holders, allowing the desired depth of engagement of the forming profiles into the workpiece material to be set. As explained, either a flat-jaw tool or a roller tool can be arranged in the tool holders.

[0029] The forming device is particularly designed to reverse the movement in the working direction once or several times during the toothing process as long as the forming tools are engaged with the workpiece. At least some of the movements in the working direction can additionally involve a relative movement between the forming tools and the workpiece in the transverse direction of the tools and / or parallel to the workpiece axis. This relative movement, which can also be referred to as a feed movement, is only performed when the first profile section of the forming tools is engaged with the workpiece.

[0030] A method for producing the gear teeth can be performed using any embodiment of a forming tool. The forming tools are first arranged on opposite sides of the part of the workpiece to be formed, or on diametrically opposite sides of the workpiece axis, and then brought into engagement with the material of the workpiece, with the two forming tools initially engaging the workpiece with their first profile sections.

[0031] Subsequently, at least one movement of the forming tools is initiated in the working direction so that the forming profiles roll on the workpiece during forming. Preferably, the rolling movement of the forming tools in the working direction is reversed at least once, wherein during some of the rolling movements in the working direction, a feed or relative movement is carried out between the workpiece and the forming tools in the transverse direction of the tools and in particular parallel to the workpiece axis. In this way, axial sections of the gearing can be produced one after the other. During a feed movement in the transverse direction of the tools or parallel to the workpiece axis, the forming tools are each in engagement with the workpiece with their first profile section. In the feed direction, the first edge section of the front profile edge is arranged adjacent to the point of engagement between the forming tools and the workpiece.

[0032] At the end of the forming process, the forming tools are brought into engagement with the workpiece with their second profile sections and a movement is performed in the working direction without causing any relative movement between the forming tool and the workpiece in the transverse direction of the tool or parallel to the workpiece axis between the workpiece and the forming tools. This movement can also be referred to as a calibration movement and is exclusively a rolling movement of the forming tools in the working direction on the workpiece.

[0033] Due to the inventive design of the forming tools and the resulting forming of the workpiece, improved forming can be achieved through the engagement of the second profile section with the part of the workpiece to be formed, even if the workpiece adjacent to the gearing to be produced has a shape or geometry that hinders complete forming because a relative movement between the forming tool and the workpiece in the transverse tool direction or parallel to the workpiece axis is not possible without limitation during forming. The workpiece may have an interfering contour, so to speak, in particular adjacent to an undercut, a recess, a groove, or another depression on the workpiece part to be formed.The design with two different profile sections of the front profile edge enables, on the one hand, relative movement in the transverse direction of the tool without chip formation and / or material removal on the workpiece. On the other hand, sufficient deformation is ensured over the entire length of the gear to be produced on the workpiece, thus ensuring high quality of the manufactured gear. The target-actual deviation of the manufactured gear can therefore maintain a specified tolerance range across the entire length of the gear parallel to the workpiece axis.

[0034] Advantageous embodiments of the invention will become apparent from the dependent claims, the description, and the drawings. Preferred embodiments of the invention are explained in detail below with reference to the accompanying drawings. The drawings show: Figure 1a schematic, block diagram-like representation of an embodiment of a forming device with forming tools for producing a gear on a workpiece, Figures 2 and 3 each a schematic representation of an axial end region that is difficult to form on a first workpiece part of the workpiece to be formed, Figure 4 a schematic representation of a target geometry of a gear to be produced on the first workpiece part, Figure 5 a schematic representation of a not with the target geometry from Figure 4 matching actual geometry of a gearing manufactured using known methods and devices, Figure 6 a schematic representation of an embodiment of a forming tool according to the invention in a side view in the tool transverse direction, Figure 7 a cross-section through the forming tool Figure 6 in a first profile section according to the section line AA, Figure 8a cross-section through the forming tool Figure 6 in a second profile section according to section line BB, Figures 9 and 10 each a cross section through a modified embodiment of a forming tool in the first profile section ( Figure 9 ) and in the second profile section ( Figure 10 ) analogous to the representations in Figures 7 and 8, Figure 11 an embodiment of a front profile edge in the second profile section of a forming tool in a view in the working direction at right angles to the tool transverse direction, Figures 12 and 13 each an embodiment of a front profile edge of a forming tool in the second profile section in a view in the working direction at right angles to the tool transverse direction, Figures 14 to 17 each schematic representation of the production of a toothing on the first workpiece part of the workpiece using any embodiment of a forming tool, Figures 18 and 19schematic representations of modified embodiments of a forming tool in the form of a roller tool.

[0035] In Figure 1 An embodiment of a forming device 20 is illustrated schematically in the manner of a block diagram. The forming device 20 is set up to produce a gear 21 on a workpiece 22. The gear 21 is produced on a rotationally symmetrical first workpiece part 23 of the workpiece 22. The first workpiece part 23 extends along a workpiece axis A, which represents the axis of symmetry for the rotational symmetry of the first workpiece part 23. The first workpiece part 23 has a cylindrical or hollow cylindrical section on which the gear 21 is to be produced. This cylindrical or hollow cylindrical section is adjoined, for example, at both axial ends by a conical section 24.

[0036] The workpiece 22 has, at the end opposite the free end of the first workpiece part 23, a second workpiece part 25 whose dimension perpendicular to the workpiece axis A is larger than that of the first workpiece part 23. The second workpiece part 25 can therefore represent an interfering contour for producing the toothing 21 in the first workpiece part 23, as will be explained further below. In the region of the conical section 24 of the first workpiece part 23, at the transition to the second workpiece part 25, there is a recess 26, which can also be referred to as an undercut or groove. The recess 26 has, for example, a trapezoidal cross-sectional shape (viewed in the circumferential direction around the workpiece axis A), but in a modification of the illustrated embodiment, it can also have other cross-sectional shapes, for example a rectangular or other polygonal and / or curved cross-sectional contour.

[0037] The forming device 20 has a holding device 29 for the workpiece 22. The holding device 29 is configured, for example, to hold the workpiece 22 rotatably about the workpiece axis A. The workpiece can be held, for example, by means of the holding device 29 at any area where no forming takes place, for example at the second workpiece part 25.

[0038] The forming device 20 also has a first tool holder 30 and a second tool holder 31. A forming tool 32 is arranged on each tool holder 30, 31. In the Figure 1 In the example shown, the forming tools 32 are each formed by a flat-jaw tool 33. The flat-jaw tool 33 can also be referred to as a rolling bar. The two tool holders 30, 31 are Figure 1The forming device 20 shown is formed by tool slides. The tool holders 30, 31 can be positioned at a suitable distance from the workpiece axis A and moved linearly at right angles to the workpiece axis A in a working direction W.

[0039] When the forming tools 32 are in engagement with the material of the workpiece 22 (for example, on the first workpiece part 23), a rolling movement takes place between the forming tools 32 and the workpiece 22 during the linear movement of the tool holders 30, 31 (in the example: tool slide). The workpiece 22 rotates about the workpiece axis A. The forming tools 32 are held by the two tool holders 30, 31 in the Figure 1illustrated embodiment in opposite directions parallel to the working direction W, wherein the first tool holder 30 with the forming tool 32 arranged thereon executes a linear movement in a first direction R1 and the second tool holder 31 with the forming tool 32 arranged thereon executes a linear movement in a second direction R2 opposite to the first direction R1 or vice versa.

[0040] The tool holders 30, 31 can reverse their movement parallel to the working direction W once or several times between the first direction R1 and the second direction R2.

[0041] Using multiple machine axes 34, the forming device 20 can control the relative movement between the workpiece 22 and the forming tools 32. For example, using machine axes 34, which are only illustrated in a highly schematic manner, the movement and / or position of the tool holders 30, 31 and the holding device 29 relative to one another can be controlled. A control device 35 is configured to control the position and / or movement of the machine axes 34. The position and / or movement of the tool holders 30, 31 and the holding device 29 can optionally be controlled in a closed control loop.

[0042] To produce the gearing 21 on the workpiece 22, in addition to a linear movement of the forming tools 32 in the working direction W, a feed or relative movement between the workpiece 22 and the forming tools 32 can take place in an axial direction X parallel to the workpiece axis A. A tool transverse direction Q of the forming tools 32 is aligned parallel to the axial direction X. The feed or relative movement is preferably carried out by a movement of the holding device 29 by means of the associated machine axis 34, but can additionally or alternatively be carried out by means of the machine axes 34, which carry out the movement of the tool holders 30, 32.

[0043] In order to enable such a feed or relative movement when the forming tools 32 are in engagement with the workpiece 22, the forming tools 32 must have a geometry that avoids chip formation or material removal on the workpiece 22, for example by forming roundings and / or chamfers on the forming tools 32.

[0044] As it is in the Figures 2 and 3 As illustrated, such a geometry of the forming tools can make forming corresponding to the desired geometry of the toothing 21 problematic. When producing the toothing 21 on the first workpiece part 23 adjacent to the second workpiece part 25 or within the recess 26, the edge geometry of known forming tools can lead to the situation that the forming tools are limited in their movement in the axial direction X by the second workpiece part 25 ( Figure 2). A complete forming is particularly problematic in the area of ​​the recess 26 present in the transition between the workpiece parts 23, 25, because the rounding or chamfer on the forming tool 32, which in this situation is arranged in the area of ​​the recess 26, does not ensure sufficient forming of the material of the workpiece 22 (here: first workpiece part 23). In particular, in an area U in Figure 3 There is insufficient engagement between the forming tool 32 and the material of the workpiece 22, and no forming takes place that produces an actual geometry of the gearing 21 that sufficiently corresponds to the target geometry. This problem is exacerbated by the recess 26.

[0045] The target geometry of the gearing 21 is in Figure 4 The actual geometry produced by the known forming tools is shown schematically in Figure 5 shown. In the area U ( Figure 3) it can be seen that due to the insufficient engagement depth between the forming tool 32 and the workpiece 22, the tooth gaps of the produced gearing 21 are not deep enough. Furthermore, this can lead to the tooth thicknesses of the teeth of the produced gearing 21 being too large in the area U. The Figure 5 The actual geometry shown would prevent the complete insertion of a component, which is to be connected in a rotationally fixed manner to the first workpiece part 23 via the manufactured toothing 21, in the axial direction X up to the second workpiece part 25.

[0046] Such an incompletely formed toothing 21 is avoided by a forming tool 32 according to the invention. A forming tool 32 according to the invention, described in detail below, can be used in the forming device 20 according to Figure 1 and / or can be advantageously used in a method for forming the workpiece 22 to produce the toothing 21.

[0047] The design of the forming tool 32 according to the invention is described with reference to Figures 6 to 13 first explained using the example of a flat jaw tool 33. The principle can also be applied to roller tools 36 that are rotatable about a roller axis D, as will be explained later with reference to the Figures 18 and 19 is explained.

[0048] In Figure 6 A forming tool 32 designed as a flat-jaw tool 33 is schematically illustrated in a side view looking in the tool transverse direction Q. The forming tool 32 or flat-jaw tool 33 extends at right angles to the tool transverse direction Q in a tool longitudinal direction L, which in this flat-jaw tool 33 is the working direction W in which the forming tool 32 or flat-jaw tool 33 is moved during the forming of the workpiece 22.

[0049] Parallel to the working direction W, the flat-jaw tool 33—or another embodiment of the forming tool 32—can be moved in the first direction R1 or the second direction R2 opposite the first direction. The first direction R1 and the second direction R2 thus represent oppositely directed directional components of the working direction W.

[0050] The forming tool 32 has a forming profile 41 on its side facing the workpiece 22 to be formed, which is referred to here as the upper side 40. The forming profile 41 has a geometry which corresponds to the geometry of the toothing 21 to be produced on the workpiece 22 in such a way that when the forming profile 41 engages in the material of the workpiece 22, the toothing 21 receives the desired geometry.

[0051] The forming profile 41 has a plurality of profile teeth 42 arranged adjacently in the tool longitudinal direction L or working direction W. The profile teeth 42 are in Figure 6 shown only partially, by way of example and schematically. Two profile teeth 42 directly adjacent in the tool longitudinal direction L are each spaced from one another by a profile tooth gap 43 arranged therebetween. The profile teeth 42 are aligned parallel to one another. They can extend in the tool transverse direction Q or obliquely to the tool transverse direction Q and thus also obliquely to the tool longitudinal direction L. This depends on whether a spur gear (gear 21 in the axial direction X) or a helical gear (gear 21 with teeth aligned obliquely to the axial direction X) is to be produced on the workpiece 22.

[0052] Each profile tooth 42 has a tooth tip with a tooth tip end 42a, which forms the outermost, free end at the tooth tip of the profile tooth 42. The highly schematic representation in Figure 6 is not to scale and merely shows two profile teeth 42 as an example in a schematic diagram.

[0053] The forming profile 41, viewed in the tool's longitudinal direction L, has, for example, an inlet area S1, a central area S2, and an outlet area S3. The inlet area S1 is optional and can be omitted.

[0054] In the exemplary embodiment, the central region S2 is arranged between the inlet region S1 and the outlet region S3, whereby the regions can be directly adjacent to one another. If, in a modified exemplary embodiment, no inlet region S1 is present, the central region S2 can have a length that corresponds to the total length of the inlet region S1 and the central region S2 in the illustrated exemplary embodiment. The number of profile teeth 42 is greater in the central region S2 than in the outlet region S3 and / or in the inlet region S1. The number of profile teeth 42 can be smaller in the outlet region S3 than in the optionally present inlet region S1.

[0055] The geometry of the forming profile 41 is constant in the central area S2 and differs from the geometry of the forming profile 41 in the inlet area S1 and / or in the outlet area S3. As shown schematically in Figure 6As can be seen, the minima of the profile tooth gaps 43 in the central region S2 (and if present also in the inlet region S1) are arranged in a common plane which is spanned by the longitudinal tool direction L and the transverse tool direction Q. In contrast, the minima of the profile tooth gaps 43 in the outlet region S3 can be arranged lower in the direction away from the central region S2. The tooth height of the profile teeth 42 is the distance between the minima of the adjacent profile tooth gap 43 and the tooth tip end 42a (free end of the profile tooth 42). The tooth height is constant in the central region S2. The tooth height is constant in the outlet region S3. The tooth height can be the same in the central region S2 and in the outlet region S3. In the optionally present inlet region S1, the tooth height decreases away from the central region, preferably continuously and more preferably linearly.

[0056] In the optionally available inlet area S1, the tooth height could also be constant and the minima of the profile tooth gaps 43 could be arranged lower in the direction away from the central area S2, similar to the outlet area S3.

[0057] A head tangent T ( Figures 7 to 10 ). The tip tangent T is a straight line that is applied from above to the tooth tip end 42a of a profile tooth 42 in such a way that it touches the tooth tip end 42a in an area in which the profile tooth 42 has its maximum tooth height. The tip tangent T can be parallel to the tool transverse direction Q ( Figures 7 and 8 ) or extend at an acute angle to the tool transverse direction Q ( Figures 9 and 10 ).

[0058] In the Figures 6 to 13In the illustrated embodiment of the forming tool 32 as a flat-jaw tool 33, the head tangents T of a single region (i.e., central region S2 or run-out region S2 or optional run-in region S1) are arranged within a common head plane, i.e., for example, within a first head plane E1 of the run-in region S1, within a second head plane E2 of the central region, and within a third head plane E3 of the run-out region. The first head plane E1 and the third head plane E3 are arranged, starting from the central region S2, inclined downwards relative to the second head plane E2 of the central region S2, wherein the inclination of the third head plane E3 can be greater than the inclination of the first head plane E1 ( Figure 6 ).

[0059] The forming tool 32 has, viewed in the longitudinal direction L of the tool, a first profile section P1 and a second profile section P2 directly or indirectly adjoining it. The first profile section P1 contains a section of the central region S2 and, for example, the inlet region S1 adjoining this section. The second profile section P2 contains the outlet region S3 and a further section of the central region S2 adjoining it. The two profile sections P1, P2 can be of equal or different lengths in the longitudinal direction L of the tool. For example, the length of the second profile section P2 in the longitudinal direction L of the tool can correspond to the length of the section that the first profile section P1 has in the central region S2. This length can correspond to the circumference of a circle around the toothing 21 to be produced on the workpiece 22 or can be longer.

[0060] In the Figures 7 to 10are cross sections through the first profile section ( Figures 7 and 9 along the section line AA in Figure 6 cut) or by the second profile section P2 ( Figures 8 and 10 along section line BB in Figure 6sectioned). The forming tool 32 or flat jaw tool 33 has, as seen in the tool transverse direction Q, a front tool side 47 and an opposite rear tool side 48. If, during the forming of the workpiece 22, a relative movement takes place between the forming tool 32 and the workpiece 22 (e.g. due to a feed movement of the workpiece 22 in the axial direction X), the front tool side 47 points forward in the direction in which the forming tool 32 moves relative to the workpiece 22. The feed or relative movement is selected such that the forming tool 32 moves relative to the workpiece 22 in a direction in which no forming has yet taken place on the workpiece 22 by the forming tool 32.

[0061] On the front tool side 47, the forming tool 32 has a front side surface 49 which is not or at least not completely in engagement with the workpiece 22 during the forming of the workpiece 22 or the production of the toothing 21. The front side surface 49 is oriented at right angles to the tool transverse direction Q in the exemplary embodiment.

[0062] In the area of ​​the forming profile 41, the front side surface 49 merges into a front profile edge 50. The front profile edge 50 thus defines the geometry in the transition area of ​​the profile teeth 42 from the tooth tip ends 42a to the front side surface 49, that is to say the geometry of the end faces of the profile teeth 42 pointing in the transverse direction Q of the tool. The front profile edge 50 has a first edge section 50a in the first profile section P1 and a second edge section 50b in the second profile section P2. In the longitudinal direction L of the tool, the first edge section 50a preferably extends along the entire first profile section P1 of the forming profile 41 and / or the second edge section 50b of the front profile edge 50 preferably extends along the entire second profile section P2.

[0063] The profile teeth 42 are aligned outside the front profile edge 50 with their respective tooth tip end 42a along the tip tangents T and are arranged in particular in the respective (virtual) tip plane E1, E2, E3. Immediately adjacent to the profile edge 50, the tip tangent T applied to the tooth tip end 42a of the respective profile tooth 42 forms a transition point C with the tooth tip end 42a. Each of the profile teeth 42 is arranged at a distance from the tip tangent T at least along the first edge section 50a of the profile edge 50, as shown schematically in Figure 7 is shown.

[0064] The front profile edge 50 is configured in the first edge section 50a such that, during a feed or relative movement (between the forming tool 32 and the workpiece 22 in the tool longitudinal direction L), it causes no chip formation and no material removal—or only an insignificant material removal—during the engagement of the forming profile 41 in the material of the workpiece 22. Insignificant material removal due to friction effects may not be completely ruled out; however, such material removal plays no role in the generated geometry of the toothing 21. The toothing 41 is, for example, generated exclusively by displacement of the material of the workpiece 22 by means of the forming tool 32 and not by material removal.

[0065] In the first edge section 50a, the profile edge 50 can have at least one chamfer 51 ( Figure 13 ) and / or at least one rounding 52 ( Figure 12 ). The rounding 52 can, as shown in the example in Figure 12 shown, have a constant radius or, alternatively, have a varying radius or curvature. The first edge portion 50a may also contain at least one chamfer 51 and at least one rounding 52 (e.g., radius) in combination.

[0066] The front profile edge 50 has along its outer surface between the front side surface 49 and the transition point C a length which is measured in a cross-sectional plane perpendicular to the tool longitudinal direction L along the course of the outer surface of the profile edge 50 and which defines an edge width b, which can be seen in particular from the Figures 11 to 13The edge width b of the two profile sections P1, P2 of the forming profile 41 differs from one another. The first edge section 50a in the first profile section P1 has a first edge width b1, and the second edge section 50b in the second profile section P2 has a second edge width b2. The second edge width b2 is smaller than the first edge width b1.

[0067] The second edge width b2 can be negligibly small in order to obtain a very sharp second edge section 50b in the second profile section P2. The profile edge 50 has only a minimal rounding and / or chamfer in the second edge section 50b, which is technically necessary during the manufacture of the forming tool 32. In any case, the second edge width b2 in the second edge section 50b is significantly smaller than the first edge width b1. For example, the second edge width b2 can be a maximum of 10%, a maximum of 5%, or a maximum of 1-3% of the first edge width b1.

[0068] As is exemplified in the Figures 9 and 10 As shown, the head tangents T or the head planes E1, E2, E3 can be inclined by an angle of inclination relative to the tool transverse direction Q, for example by a first angle of inclination α in the first profile section P1 ( Figure 9 ) and a second inclination angle β in the second profile section P2 ( Figure 10). Preferably, the value of the first angle of inclination α is smaller than the value of the second angle of inclination β. The principle diagrams of the Figures 9 and 10 are not to scale. In fact, the inclination angles α and β are very small and can be less than 1 / 1000° (e.g., α ≈ (3*10 -5< )°, β ≈ (4*10 -4< )°).

[0069] In addition or alternatively to the different inclination angles α, β, a tool height z in the first profile section P1 and in the second profile section P2 can be different in a vertical direction Z of the forming tool 32 along the front side surface 49 or on the front tool side 47. The vertical direction Z is oriented at right angles to the tool transverse direction Q and at right angles to the tool longitudinal direction L. Figures 9 and 10 .

[0070] The tool height z of the flat-jaw tool 33 is measured from a bottom side 53 opposite the forming profile 41 in a direction perpendicular to the tool transverse direction Q and perpendicular to the tool longitudinal direction L up to a point at which the forming profile 41 is at the greatest distance from the bottom side 53. A maximum first tool height z1 in the first profile section P1 is preferably smaller than a maximum second tool height z2 in the second profile section P2. In particular, both the first tool height z1 and the second tool height z2 are determined in the central region S2. The first tool height z1 and the second tool height z2 can also be the same.

[0071] The front profile edge 50 has an edge height h in the vertical direction Z. The edge height h is the distance in the vertical direction Z between the transition of the profile edge 50 into the front side surface 49 and the transition point C (front end point in the tool transverse direction Q at the tooth tip end 42a, at which the tip tangent T touches the tooth tip end 42a of the profile tooth 42). Preferably, a first edge height h1 in the first edge section 50a of the front profile edge 50 is greater than a second edge height h2 in the second edge section 50b of the front profile edge 50.

[0072] Based on the Figures 14 to 17The production of the toothing 21 on the first workpiece part 23 of the workpiece 22 is explained by way of example using a forming tool 32 designed as a flat-jaw tool 33. Instead of flat-jaw tools 33, the method described below can also be carried out in an analogous manner using the rolling tools 36 shown as examples in Figures 18 and 19.

[0073] First, the forming tools 32 are positioned on opposite sides or diametrically opposite the workpiece axis A. The forming profiles 41 face each other or face the workpiece axis A. The working direction W and thus the first direction R1 and the second direction R2 are aligned perpendicular to the workpiece axis A.

[0074] The two forming tools 32 are aligned with their tool transverse direction Q parallel to the axial direction X and thus parallel to the workpiece axis A. They are first brought into engagement with the first profile section P1 from opposite sides with the first workpiece part 23 to be formed. In the tool transverse direction Q, initially only a part of the forming profile 41 can be in engagement with the material of the first workpiece part 23, as is exemplified in Figure 14 is shown. The first engagement with the first profile section P1 can optionally only occur while the forming tools 32 are already moving in the tool longitudinal direction L.

[0075] After the forming tools 32 have been brought into engagement with the first workpiece part 23, one forming tool 32 is moved in the first direction R1 and the other forming tool 32 is moved in the opposite second direction R2. The forming profiles 41 roll on the first workpiece part 23 and a first axial region of the toothing 21 to be produced is created along the circumference of the first workpiece part 23. Following this first movement (rolling) of the forming tools 32, each forming tool 32 can reverse its movement in the working direction W. The forming tool 32 previously moved in the first direction R1 is then moved in the second direction R2 and conversely the forming tool 32 previously moved in the second direction R2 is then moved in the first direction R1. The direction reversal can take place once or several times.

[0076] Combined with the movement of the forming tools in the working direction W (first direction R1 or second direction R2), there is also a relative movement of the forming tools 32 with respect to the workpiece 22 in the tool transverse direction Q and thus in the axial direction X, which is shown schematically in Figure 15is shown. This relative movement can be carried out by means of a linear feed movement, preferably of the workpiece 22 and / or optionally of the forming tools 32. During this relative movement in the axial direction X with simultaneous engagement of the forming profiles 41 in the material of the workpiece 22 (here: the first workpiece part 23), the first profile sections P1 of the forming profiles 41 are in engagement with the material of the workpiece 22, so that the first edge section 50a of the front profile edge 50 moves forward in the axial direction X at the engagement point, i.e. in a direction in which no forming of the first workpiece part 23 has yet taken place. Such a superimposed movement of the forming tools 32 in the first direction R1 or the second direction R2 with simultaneous relative movement to the workpiece 22 in the axial direction X can be carried out once or several times in succession.Each of the forming tools 32 can perform multiple strokes in the working direction W and reverse the direction of movement between two consecutive strokes, so that a reciprocating movement in the first direction R1 and the second direction R2 takes place. During each stroke or only during certain strokes of the forming tools 32 in the working direction W, the relative movement to the workpiece 22 in the axial direction X can also be performed.

[0077] The strokes with superimposed feed or relative movement of the forming tools 32 relative to the workpiece 22 in the tool transverse direction Q and thus in the axial direction X are in Figure 17schematically represented by the arrows running obliquely to the workpiece axis A. During these strokes, the forming tools 32 with their first profile sections P1 of the forming profile 41 are in engagement with the material of the workpiece 22 and, for example, the first workpiece part 23. The feed or relative movement is therefore only carried out when the forming tools 32 are in engagement with the material of the workpiece 22 with the first edge section 50a blunted by at least one chamfer 51 and / or at least one rounding 52 in order to avoid chip formation or material removal on the workpiece 22.

[0078] In Figure 16, the situation is schematically illustrated in which a further relative movement of the forming tools 32 with respect to the workpiece 22 in the axial direction X is no longer possible due to the geometry of the workpiece 22 and, for example, of the second workpiece part 25. However, in order to achieve complete forming in the region of the recess 26, the forming tools 32 are finally - at least in phases - brought into engagement with the workpiece 22 and here the first workpiece part 23 with their second profile sections P2. In this second profile section P2, the front profile edge 50 along the second edge section 50b is sharper than in the first edge section 50a of the first profile section P1 and ensures that a sufficiently deep orcomplete engagement of the profile teeth 42 of the forming profile 41 takes place, so that a toothing 21 corresponding to the required tolerances is produced over the entire axial length of the first workpiece part 23 to be formed. By means of the second profile sections P2, a calibration forming of the first workpiece part 23 is carried out, so to speak. The geometry of the toothing 21 is thereby produced with sufficient accuracy in accordance with the specified target geometry, even in the region of the recess 26 or close to the second workpiece part 25. During the engagement of the second profile sections P2 in the material of the workpiece 22, a single stroke or several alternating reciprocating strokes in the first direction R1 and the second direction R2 can be carried out with each forming tool 32 in the working direction W.In any case, no relative movement of the forming tools 32 with respect to the workpiece 22 in the axial direction X takes place when the second profile sections P2 engage in the material of the workpiece 22.

[0079] As already explained, the inventive design of the forming tool 32 can be used both on flat-jaw tools 33 and on roller tools 36, and the workpiece 22 can be formed in the manner explained above. The essential difference is that the flat-jaw tools 33 are moved linearly in the working direction W (first direction R1 and second direction R2), while the roller tools 36 are partially or completely rotated about their respective roller axis D. The working direction W in this design is a circumferential direction about the respective roller axis D. A first direction of rotation about the roller axis D defines the first direction R1, and an opposite direction of rotation about the roller axis D defines the second direction R2 ( Figure 18 ).

[0080] The different areas, for example the inlet area S1, the central area S2 and the outlet area S3, do not adjoin one another in the longitudinal direction L of the roller tool 36, but rather in different angular areas in the circumferential direction around the roller axis D. The same applies to the profile sections P1, P2. The different areas S1 to S3 and P1, P2 are in Figure 19 can be seen in the schematic representation of the roller tool 36.

[0081] How it turns out Figure 18 As can be seen, during the forming of the workpiece 22 or the production of the gearing 21 on the workpiece 22, the roller axes D are aligned parallel to one another and parallel to the workpiece axis A. The roller axes D run in the tool transverse direction Q.

[0082] The design of the front profile edge and the forming profile 41 in the roller tools 36 is analogous to the flat jaw tools 33, so that reference can be made to the above description.

[0083] The head tangents T of the roller tools 36 do not extend in a respective common plane, as in the case of the flat jaw tools 33, but rather, corresponding to the curved circumferential surface of the roller tools 36, in a virtual head surface arranged coaxially around the respective roller axis D. The head surface can be a cylindrical surface or a conical surface, depending on whether the head tangents T extend parallel to the roller axis D and parallel to the tool transverse direction Q or inclined thereto at an inclination angle α, β - analogous to the explanations with regard to the Figures 9 and 10 .

[0084] The invention relates to a forming tool 32 for producing a toothing 21 on a workpiece 22. The forming tool 32 has a forming profile 41 with a plurality of profile teeth 42 which extend parallel to one another and are arranged adjacent to one another in a working direction W. In a tool transverse direction Q, perpendicular to the working direction W, the profile teeth 42 merge into a front side surface 49 along a front profile edge 50. The forming profile 41 has two directly or indirectly adjoining profile sections P1, P2 in the working direction W. In a first profile section P1, the front profile edge 50 has a first edge section 50a with a first edge width b1 and in a second profile section P2, a second edge section 50b with a second edge width b2. The second edge width b2 is smaller than the first edge width b1. The second edge section 50b is, so to speak, sharper-edged than the first edge section 50a.The first edge section 50a is designed such that during a feed or relative movement transverse to the profile edge 50 with engagement of the forming profile 41 in the material of the workpiece 22, no chip is removed from the workpiece 22. List of reference symbols:

[0085] 20Forming device 21Gearing 22Workpiece 23First workpiece part 24Conical section of the first workpiece part 25Second workpiece part 26Recess 29Holding device 30First tool holder 31Second tool holder 32Forming tool 33Flat jaw tool 34Machine axis 35Control device 36Rolling tool 40Top side 41Forming profile 42Profile tooth 43Profile tooth gap 47front tool side 48rear tool side 49front side surface 50front profile edge 50afirst edge section of the front profile edge 50bsecond edge section of the front profile edge 51chamfer 52rounding 53underside of the forming tool αfirst inclination angle βsecond inclination angle AWorkpiece axis bEdge width b1First edge width b2Second edge width CTransition point DRoll axis E1First head plane E2Second head plane E3Third head plane hEdge height h1First edge height h2Second edge height LTool longitudinal direction P1First profile section P2Second profile section R1First direction R2Second direction S1Inlet area S2Central area S3Exit area QTool transverse direction THead tangent UArea of ​​the manufactured gear WWorking direction XAxial direction zTool height z1First tool height z2Second tool height

Claims

1. A forming tool (32) for producing a toothing (21) on a workpiece (22), comprising: - a forming profile (41) having profile teeth (42), which has a first profile section (P1) and a second profile section (P2) that are arranged adjacent to one another in a working direction (W) of the forming tool (32), wherein the profile teeth (42) extend obliquely or parallel to a tool transverse direction (Q) that is oriented at right angles to the working direction (W), - a front side surface (49), wherein the profile teeth (42) merge into the front side surface (49) at a front profile edge (50), and wherein an edge width (b) of the profile edge (50) is defined as the length of the front profile edge (50) from the side surface (49) to a transition point (C) that is located at an adjacent tooth tip (42a) of a profile tooth (42) and a tip tangent (T) that touches thereon is formed,- a first edge portion (50a) of the front profile edge (50) along the first profile portion (P1), which has a first edge width (b1), - a second edge portion (50b) of the front profile edge (50) along the second profile portion (P2), which has a second edge width (b2) smaller than the first edge width (b1).

2. Forming tool according to claim 1, wherein the front profile edge (50) has at least one chamfer (51) and / or at least one rounding (52) between the transition point (C) and the front side surface (49) in the first edge section (50a).

3. Forming tool according to claim 1 or 2, wherein the front profile edge (50) between the transition point (C) and the front side surface (49) in the second edge section (50b) is designed without a chamfer and without rounding.

4. Forming tool according to one of the preceding claims, wherein the forming profile (41) has an inlet region (S1), an outlet region (S3) and a central region (S2) arranged between the inlet region (S1) and the outlet region (S3).

5. Forming tool according to claim 4, wherein the inlet region (S1) is arranged in the first profile section (P1).

6. Forming tool according to claim 4 or 5, wherein the run-out region (S3) is arranged in the second profile section (P2).

7. Forming tool according to one of claims 4 to 6, wherein at least a part of the central region (S2) is arranged in the first profile section (P1).

8. Forming tool according to one of claims 4 to 7, wherein a part of the central region (S2) is arranged in the second profile section (P2).

9. Forming tool according to one of the preceding claims, designed as a flat jaw tool (33) which is linearly movable in the working direction (W).

10. Forming tool according to one of claims 1 to 8, designed as a roller tool (36) rotatable about a roller axis (D), the working direction (W) of which is a circumferential direction about the roller axis (D).

11. Forming tool according to one of the preceding claims, wherein the head tangents (T) in the first profile section (P1) are inclined relative to each other with respect to the head tangents (T) in the second profile section (P2), 12. Forming device (20) for producing a toothing (21) on a workpiece (22), comprising: - a first tool holder (30) with a forming tool (32) according to one of the preceding claims arranged thereon, - a second tool holder (31) with a forming tool (32) according to one of the preceding claims arranged thereon, - a holding device (29) which is designed to arrange the workpiece (22) between the two forming tools (32) so as to be rotatable about a workpiece axis (A).

13. Forming device according to claim 12, which is designed to reverse a movement of the forming tools (32) when producing the toothing (21) on the workpiece (22) in the working direction (W), wherein the reversal of direction occurs when a forming point between the forming tools (32) and the workpiece (22) is located in the first profile section (P1).

14. Forming device according to claim 12 or 13, which is designed to carry out a relative movement between the forming tools (32) and the workpiece (22) in the tool transverse direction (Q) when the first profile sections (P1) of the forming tools (32) and the workpiece (22) are in engagement.

15. A method for producing a toothing (21) on a workpiece (22), comprising: - arranging a first forming tool (32) and a second forming tool (32), which are designed according to one of claims 1 to 13, with one of the facing forming profiles (41) on opposite sides of the workpiece (22), - engaging the first profile sections (P1) of the forming tools with the workpiece (22), - generating at least one movement of the forming tools (32) in the working direction (W), wherein the first profile sections (P1) of the forming tools (32) are engaged with the workpiece (22), - carrying out at least one relative movement between the forming tools (32) and the workpiece (22) in the tool transverse direction (Q) during the movement of the forming tools (32) in the working direction (W), wherein the first profile sections (P1) of the forming tools (32) are engaged with the workpiece (22),- generating at least one movement of the forming tools (32) in the working direction (W) at which the second profile sections (P2) of the forming tools (32) are in engagement with the workpiece (22).

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