Method for generating grinding and profiling of gears

Abstract

1. A method for hard micromachining of gear teeth on a workpiece using geometrically undefined cutting edges by generating grinding, wherein a grinding worm, in particular a multi-start grinding worm with bonded abrasive grains made of CBN or diamond, is brought into machining engagement with the gear teeth at a machining position and is re-profiled after machining one or more workpieces of a workpiece batch, thereby undergoing material removal and thus reducing the central pitch diameter of the grinding worm before being used for further machining, and during re-profiling a profiling means is positioned by a rotation axis relative to the orientation of the worm thread, and material removal is carried out in particular at a profiling position different from the machining position, accompanied by removal of metal material binding the abrasive grains.

Description

[Technical Field]

[0001] The present invention relates to a method for hard micromachining of gear teeth on a workpiece using geometrically undefined cutting edges by generating grinding, in which a grinding worm, in particular a multi-start grinding worm with bonded abrasive grains made of CBN or diamond, is brought into machining engagement with the gear teeth in a machining position and is reprofiled after machining one or more workpieces of a workpiece batch, thereby subjecting the grinding worm to material removal and thus reducing the central pitch diameter before being used for further machining, and during reprofiling a profiling means is positioned by a rotation axis relative to the orientation of the worm thread.

[0002] Generating grinding of gears is well known to those skilled in the art as one of the primary methods for hard micromachining of gear teeth. Grinding worms used for this purpose have been developed according to two different tooling strategies.

[0003] For example, there are electroplated metal worm bodies with a fixedly defined central pitch diameter and a relatively long service life, which eventually wear out due to continuous machining wear and must be reconditioned by recoating, so-called non-dressable worms (T. Bausch, Innovative Zahnradfertigung, 3rd Edition, p. 519, Fig. 14.4-8).

[0004] On the other hand, so-called dressable grinding worms are based on the use of ceramic or resin-bonded abrasive grains. As soon as these dressable grinding worms no longer cut sharply enough, they are dressed (also called re-grinding or re-profiling), with each re-profiling step resulting in material removal, making the grinding worm smaller and smaller, i.e., changing its central pitch diameter (T. Bausch, see same diagram above).

[0005] The time required for re-profiling depends on the dressing technique used: for example, if a dressing roll is used and the dressing process is carried out continuously in line contact with the rotating grinding worm and correspondingly aligned axial displacement of the dresser, the re-profiling process takes such a short time that it can even be carried out on the generating grinding machine itself, with a correspondingly short interruption of the main machining process.

[0006] There are several variations in this embodiment: for example, as disclosed in EP 1 146 983 B1, the grinding worm can be pivoted from its generating grind machining position to a dressing position, dressed there, and then pivoted back again, or the grinding worm can remain completely in its machining position and the dresser can be moved relative to the grinding worm to approximately the same position where the workpiece to be ground would normally be positioned.

[0007] The present invention is based on the object of further developing a method of the aforementioned type with regard to a satisfactory combination of the overall service life of the grinding worm, the machining precision and the service life between the two re-profiling processes.

[0008] From a process engineering point of view, this object is achieved by a further development of a method of the type described above, which method is essentially characterized in that material removal is carried out with the removal of the metallic material (M) that binds the abrasive grains, in particular at a profiling position different from the machining position.

[0009] The invention is based on the recognition that, despite the highly complex shape of a grinding worm with a worm thread, re-profiling is still possible despite the metal bonding material, and that the longer time required for re-profiling can be well tolerated compared to conventional dressing, especially when the profiling position is different from the generating grinding machining position and the grinding worm has to be removed from its generating grinding clamp on the generating grinding machine.

[0010] Ideally, at least two, in particular three or more, even five or more, in particular seven or more grinding worms suitable for the batch of workpieces to be machined are available for the method and can be used in the method in alternating rotations. In this connection, it is particularly preferred that the grinding worm is changed / re-profiled only after at least 600, preferably at least 1000, in particular at least 2000 workpieces have been ground in generating grinding with the worm.

[0011] In a further preferred embodiment it is provided that the material removal is performed by carrying out a relative movement between the profiling means and the grinding worm, said movement comprising at least two axes of movement, in particular linear axes of movement.

[0012] The path of this relative movement is preferably a zigzag path in an axial cross section through the grinding worm rotation axis and follows the worm thread profile. In the case of a multi-start worm, the re-profiling is therefore not performed start by start, but the path of movement traverses the thread profiles belonging to the different starts.

[0013] In another preferred embodiment, it is provided that the grinding worm is rotated / turned about its axis during material removal or at stages when material removal is interrupted.

[0014] Preferably, the re-profiling is performed segment by segment using azimuthal segmentation relative to the worm axis of rotation. If the re-profiling is performed at a preset worm rotation position (apart from any additional corrective movements) so that material is removed in discrete re-profiling steps around the circumference of the grinding worm, then in one or more roughing passes, the grinding worm axis of rotation is driven in increments of at least 2 degrees, preferably at least 5 degrees, but also more than 10 degrees, and in one or more finishing passes, especially the final re-profiling pass, the grinding worm axis of rotation is driven in increments of at least 0.5 degrees, preferably at least 1 degree, and / or not more than 30 degrees, more preferably not more than 20 degrees, in particular not more than 10 degrees. More preferably, the quotient of 360 degrees and the number of worm threads is an integer multiple of the increments.

[0015] Such azimuthal discontinuous re-profiling also has the advantage that the resulting polygonal-like surface structure provides favorable properties during grinding (see below). In an alternative embodiment, the grinding worm may rotate continuously (but especially at a non-constant speed) and thus be profiled in a manner similar to line dressing.

[0016] In a further preferred embodiment, the heat involved in the material removal is dissipated via a liquid, and for this purpose, it is specifically provided that both the profiling means and the warm area currently being re-profiled are immersed in a liquid bath. This allows for more efficient heat dissipation. In this connection, it is also preferred that the liquid in the liquid bath is replaced periodically, in particular even continuously. This means that the material being removed can be removed immediately if necessary.

[0017] In another preferred embodiment, it is provided that the orientation of the worm thread in the re-profiling region is set in a predetermined direction relative to a plane extending through the rotation axis and perpendicular to the worm rotation axis, in this way even profiling means with geometrical limitations can be used.

[0018] In this connection, it is preferably provided that the profiling means has an area under tensile stress along this predetermined direction, said area extending longitudinally along this direction, and therefore the profiling means has a geometry that is significantly different from that of the dressing rolls typically used for re-profiling grinding worms.

[0019] In a further preferred embodiment, it is provided that the relative positioning of the profiling means and the orientation of the thread of the grinding worm is based on the absolute movement of the grinding worm, which makes it easier to maintain the tensile stress and does not require any effort to access the profiling means.

[0020] In another preferred embodiment, it is provided that continuously successive parts of the profiling means enter the area of ​​material removal in a particularly continuously successive manner, which increases the accuracy of the re-profiling.

[0021] In yet another preferred embodiment, it is provided that the material removal is carried out by electrical discharge machining, in particular by wire erosion. This further development is based on the further surprising discovery that, despite the complex worm thread profile, the measures described above allow a machining precision sufficient for the wire erosion method known for more than 60 years.

[0022] From the viewpoint of device technology, a hard micromachining tool using a geometrically undefined cutting edge in the form of a grinding worm for generating grinding of gears is provided for the method according to any of the aforementioned aspects. Preferably, the grinding worm still has a radial re-profiling margin of at least 1 mm, preferably at least 2 mm, more preferably at least 5 mm, and particularly at least 10 mm after initial profiling. During blank production, a metal bond material may be sintered with abrasive grains onto a metal body (located radially inward), preferably made of steel, more preferably embodied as a shaft, particularly hollow so that it can be received by a mandrel. In another preferred embodiment, the outer diameter of the grinding worm is less than 300 mm, more preferably less than 200 mm, and particularly less than 120 mm after initial profiling.

[0023] In another preferred embodiment, the grain size of the abrasive grains is B151 / D151 or less, more preferably B91 / D91 or less, and particularly B64 / D64 or less. The metal bond material of the grinding worm is not particularly limited. For example, a material containing or consisting of bronze or brass is preferred, but other conductive metal materials, preferably having a melting point below 1000 degrees Celsius, are also contemplated.

[0024] In another preferred embodiment, a calibration device is provided for obtaining defined rotational angular positions of the grinding worm in the profiling device, which can be realized in the form of a mandrel that is clamped only at defined rotational positions and supports the worm at the defined rotational positions, or for example by a flat tangent plane area that follows the axial worm end in the axial direction and extends perpendicular to the radial direction of the worm rotation axis.

[0025] The calibration device allows a reliable initial adjustment of the position of the erosion wire during re-profiling in the shift direction, i.e. along the axial axis of the degree of freedom of movement of the profiling device, to fit the worm thread.

[0026] With regard to re-profiling, the present invention provides a method for re-profiling a grinding worm according to claim 9, which method comprises a material removing step according to claim 1, a relative positioning step therefor and in particular one or more characterizing steps according to claims 2 to 8. The advantages of this re-profiling process will be clear from the above description of the preceding claims.

[0027] The scope of the present invention therefore also includes a profiling device for such profiling, i.e., a profiling device for profiling a grinding worm as embodied in claim 9, wherein the positioning device has a rotation axis for positioning the profiling means relative to the orientation of the worm thread, and in particular has a liquid-filled receiving space for receiving at least one region of the grinding worm that is to undergo material removal as well as the abrasive region of the profiling means. The advantages of such a profiling device are also already clear from the above description.

[0028] A simple design variant of such a profiling device may provide for coupling the positioning device to a rotatable and twistable receptacle for receiving the grinding worm and integrating this coupled device into a system that already has two linear positioning axes, such as, for example, a commercially available erosion device.

[0029] However, it will be appreciated that a targeted redesign of a suitable wire erosion machine may also be considered, including the possibility of integrating it into a generating grinder and enabling the use of the generating worm's axis of motion during generating grinding for profiling. In the latter case, the grinding is also preferably used as a dielectric medium during generating grinding.

[0030] In a further preferred embodiment, there is provided a profiling device as claimed in claim 11, comprising a device for rotating the grinding worm about its own axis of rotation and a further positioning system having at least two further degrees of freedom of movement for the relative position between the grinding worm and the profiling means, one degree of freedom having a movement component in a plane extending perpendicular to the worm axis of rotation and the other further degree of freedom having at least one directional component parallel to the worm axis of rotation.

[0031] In another preferred embodiment there is provided a profiling device as claimed in claim 12, which comprises a controller which, in an operating mode with a positioned rotation axis and a positioned rotation position of the grinding worm, includes two additional degrees of freedom of movement and enables relative movement along a zigzag path corresponding to the worm profile in the axial cross section.

[0032] In another preferred embodiment, there is provided a profiling device as defined in any one of claims 11 to 13, wherein the / a control device of the profiling device in a second operating mode superimposes superimposed movements of positioning and zigzag paths to subject the surface of the worm thread to modifications, in particular profile angle modifications, profile line crowning, tooth tip and / or root relief, and during generating grinding with a grinding worm profiled in this modified way imparts corresponding modifications on the generated ground workpiece, the modifications profiled on the grinding worm in particular including a coordinated superposition of these modifications, the modifications including corrections to compensate for the additional profiling and the resulting changed central pitch diameter.

[0033] In particular, it is provided that the positioning and feed movements during the profiling path are automatically performed by the profiling device's control device and are also performed by closed-loop control. As is customary in erosion, in addition to the geometric parameters to be created, additional input parameters, such as the machining accuracy (entered as a radius) and the desired cutting performance, may be specified / entered, and a typical erosion software function will automatically set the additional erosion parameters. For example, the feed rate may be controlled as a function of the amperage, the distance between the wire and the worm thread surface to be machined, and the desired removal rate. Depending on the material selected for the grinding worm, a test and learn phase is used to determine which wire erosion parameters result in which type of removal, which can be determined by conventional measurements of the generating worm. It will be understood that the parameters and feed rate of the profiling device embodied as an erosion machine are set in a coordinated manner to initially profile and then re-profile, respectively, a grinding worm profile designed in a conventional manner for generating grinding.

[0034] The wire axis is not available as a degree of freedom in the wire erosion process to perform the aforementioned modifications to the grinding worm profile to impart or compensate for the corresponding tooth flank modification on the generated ground workpiece. Since, among other things, discontinuous profiling can be selected as described above, the available degrees of freedom are essentially the aforementioned basic profiling via the axial and radial positioning axes in the form of the linear motion axes X and Y and the rotation axis B and the pivot axis A (relative rotational positioning axes), plus δA, δB, δX, δY as corrective superimposed movements to form the worm thread profile, thus providing a degree of freedom similar to that of so-called mechanical line dressing. The "polygon-like structure" generated by azimuthally discrete reprofiling can be correspondingly refined by refining the increments, so that, in this embodiment as well, a close correspondence to the line dressing contact area can be achieved.

[0035] It will be appreciated that the above-described profiling device can also be used for the initial profiling of the grinding worm according to the invention. For this purpose, a relatively slow single "cut-out" pass through the solid material in terms of radial depth can be performed. Of course, the kinematic coupling between the dresser and the worm rotation (axial displacement relative to the worm rotation) that occurs during conventional dressing must be matched by an axial displacement with a corresponding pitch ratio in order to maintain the worm thread form as the drive continues incrementally in the direction of the worm rotation.

[0036] A preferred method design for generating grinding also provides that the generating grinding worm is multi-start, preferably with a start number of at least 3, more preferably at least 4, in particular at least 5, and / or has a central pitch angle of more than 2 degrees, preferably more than 4 degrees. Values ​​in the interval [0.5;5] are preferred for the worm modulus.

[0037] Another preferred method design provides, as already mentioned above, that a polygonal surface structure in the circumferential direction of the generating grinding worm is created during re-profiling, which contributes positively to reducing the grinding pressure and also leads to an improved coolant / lubricant supply.

[0038] The method aspect of electrical discharge machining, particularly reprofiling of a generating grinding worm by wire erosion, can also be used to bond essentially non-metallic but nevertheless conductive or made conductive, such as carbon compounds or synthetic resin bonds made conductive by metal additives. This aspect is also disclosed by the present invention as an independent and intrinsically worthy of protection. The present invention relates to a method for hard micromachining of gear teeth on a workpiece using a geometrically undefined cutting edge by generating grinding, in which a grinding worm, particularly a multi-start grinding worm with bonded abrasive grains made of CBN or diamond, is engaged with the gear teeth at a machining position and reprofiled after machining one or more workpieces of a workpiece batch, thereby removing material and thus reducing the central pitch diameter of the grinding worm before use in additional machining. During reprofiling, a profiling means is positioned by a rotation axis relative to the orientation of the worm thread, and material removal is carried out at a profiling position different from the machining position, along with removal of conductive or conductive material bonding the abrasive grains by electrical discharge machining, particularly by wire erosion. The above comments regarding the corresponding creation worm and initial profiling apply equally.

[0039] In generating grinding worms with axial regions of different design that are also contemplated by the present invention, one or more of these regions may be made of a non-metallic but conductive bonding material, e.g., an abrasive region, which may nevertheless be reprofiled for rough and / or finish generating grinding along with other, e.g., metallic, regions.

[0040] Further features, details and advantages of the present invention can be found in the following description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0041] [Figure 1A] 10 shows a schematic representation of azimuthally discrete profiling. [Figure 1B]10 shows a schematic representation of azimuthally discrete profiling. [Figure 1C] 10 shows a schematic representation of azimuthally discrete profiling. [Figure 2] 1 shows the path of the feed motion during re-profiling. [Figure 3] 1 shows the placement of the calibration surface near the end of the axial grinding worm. [Figure 4A] 1 shows the positioning of the profiling means relative to the orientation of the worm thread. [Figure 4B] 1 shows the positioning of the profiling means relative to the orientation of the worm thread.

[0042] First, the machining sequence for the initial profiling of the grinding worm is described in the sequences 1A-1C using Figure 1. A blank for the future grinding worm 1, initially cylindrical and having a completely unmachined surface 2, is pre-profiled at a given rotational position of the worm rotation axis B in the initial profiling region 3. The worm thread in region 3 is formed by cutting into the solid material, and the resulting material chips fall into a bath in which the grinding worm 1 is at least partially immersed for profiling. This process is repeated several times in rotational positions, with the cutting means being shifted along the worm's axial axis Z from one rotation B increment to the next by the corresponding pitch ratio, until the profile region 3 extends around the entire circumference of the worm. At a given rotational position, the cutting means moves along a radial-axial path s, as shown in Figure 2.

[0043] During rough cutting (FIG. 1B), rotation continues between two increments by an amount of 360° / n a total of (n-1) times, thereby generating a segmented structure of polygonal features in the azimuthal direction that becomes finer as n increases. The rough cutting process itself may be performed in one or more passes, i.e., at different radial cutting depths, but is preferably performed in only one pass.

[0044] The final worm shape is preferably achieved in one or more finishing passes. These proceed substantially similarly to the roughing passes, but with finer, gradual transitions, preferably driven in increments of 360° / m, preferably m>n. In certain exemplary embodiments, n may be, for example, 72 and m may be, for example, 180. It will be appreciated that the axial displacement in Z changes accordingly after a rotation ΔB=360° / n or 360° / m, according to the corresponding pitch ratio.

[0045] In one embodiment, a flat tangential surface 6 is formed on the axial end of the worm 1 as an orientation surface, so that a straight line (g) extending parallel to the tangential surface corresponds to the worm rotation position B0 associated with this tangential plane position. This tangential surface therefore serves as the calibration surface 6. The grinding worm is placed on a sleeve 16 which, like the grinding worm 1, is placed on a mandrel 12.

[0046] 2 is a two-start worm, but the invention particularly preferably provides for worms with more than two starts, but is also applicable to single-start worms. In the case of multiple starts, the path s crosses the starts one after the other, and profiling is not performed start by start, but in the azimuthal domain, and thus for multiple starts in one profiling pass.

[0047] As can be seen from FIGS. 4A and 4B, in the profiling position, the grinding worm 1 can not only rotate around its own axis, which has a rotation axis B, but also swivel with a pivot axis A. Via the pivot axis A, the grinding worm 1 can be moved to a pivot position (A0), in which the worm thread 4 extends toward the machining side along a predetermined orientation corresponding to the height axis H in the exemplary embodiment according to FIG. 4. In this vertical alignment, the pivot angle A0 corresponds to the pitch angle of the grinding worm 1. In FIG. 4A, the pivot unit for pivoting the grinding worm is identified with the reference numeral 20, and the rotation unit for rotating the grinding worm 1 around its own axis is identified with the reference numeral 10. In this exemplary embodiment, both the HSK profiling mandrel for the grinding worm 1 and the adapter coupling for clamping are designed in stainless steel versions. For simplicity, neither the tank in which the profiling process takes place nor its edges are shown in FIGS. 4A and 4B.

[0048] In this exemplary embodiment, the grinding worm 1 is designed to include a radially inner steel body carrying an outer body made of bronze or brass with CBN abrasive grains bonded to it. In this exemplary embodiment, the outer diameter during initial profiling is 80 mm, and the outer diameter of the steel body is 55 mm. The grinding worm may therefore be reprofiled over a radial depth of 12.5 mm minus the thread depth. The reprofiling is performed in a manner very similar to the initial profiling described above, except that the reprofiling itself may be sufficient to perform finishing (FIG. 1C), but the zero position for subsequent positioning of the profiling means may be found in advance using a calibration surface 6. However, this calibration surface is merely a specific variation of a calibration device for obtaining the worm rotational position, and the present invention is not limited thereto. A rough cut may also be performed prior to the reprofiling.

[0049] In this exemplary embodiment, the cutting mechanism for profiling is electrical discharge machining, specifically the wire erosion method. In Figures 4A and 4B, the wire for the wire erosion process is identified by the reference numeral 30, and its diameter preferably ranges from 0.05 mm to 0.5 mm. Thus, the grinding worm 1 is wetted with a liquid, at least in the area to be machined (the liquid serves as a dielectric medium for the process), and a voltage is applied between the erosion wire 30 and the conductive material M of the grinding worm 1 to be removed. For example, the erosion machine can be a standard commercially available erosion machine, but it needs to be modified to provide the intended rotation and pivot axes (B, A), as realized by the combined swivel and rotation unit (20, 10), as shown in Figure 4A. Additionally, the erosion wire 30 can be moved relative to the worm 1 along the linear motion axes X, Y shown in Figure 4A to move along the path s (Figure 2).

[0050] Furthermore, the grinding worm 1 may have different zones along its axial extension in terms of their cutting performance or grain size. For example, a first axial zone may use coarse grinding particles, while a second axial zone may use finer, i.e., finer, grains. For example, it may be possible to have one metal bond material with a coarse filler and one with a fine filler, which bond the abrasive grains. However, reprofiling of both zones may also be performed in one pass. Alternatively, two separately manufactured disks may be combined to form a combined tool.

[0051] In a simple design, the unit comprising the swivel unit 20 and the rotation unit 10 is arranged so that the entire grinding worm 1 is immersed in a bath with a liquid as a dielectric medium, preferably water, which may be a special liquid or oil according to its function acting as an EDM dielectric medium.

[0052] After re-profiling, the grinding worm 1 is returned to the generating grinding machine and continues to be used.

[0053] The above specification is intended to be illustrative of the present invention and should not be construed as limiting the scope of the following claims.

Claims

1. 1. A method for hard micromachining of gear teeth on a workpiece using a geometrically undefined cutting edge by generating grinding, comprising: a grinding worm (1), in particular a multi-start grinding worm with bonded abrasive grains made of CBN or diamond, brought into working engagement with the gear teeth in a working position and re-profiled after machining one or more workpieces of a workpiece batch, thereby subjecting the grinding worm to material removal and thus reducing the central pitch diameter before being used for further machining; during re-profiling, a profiling means (30) is positioned by a rotation axis (A) relative to the orientation of the worm thread; A method characterized in that said material removal is carried out with the removal of metallic material (M) binding said abrasive grains, in particular at a profiling position different from said machining position.

2. 2. The method according to claim 1, wherein the material removal is performed by performing a relative movement between the profiling means and the grinding worm, the movement comprising at least two axes of movement, in particular linear axes of movement (X, Y).

3. 3. A method according to claim 1 or 2, wherein the grinding worm is rotated / turned (B) about its axis during the material removal or at stages when material removal is interrupted.

4. 4. The method according to claim 1, wherein the heat associated with the material removal is dissipated via a liquid, and for this purpose, in particular, both the profiling means (30) and the warm area that is currently being reprofiled are immersed in a liquid bath.

5. 5. The method according to claim 1, wherein a calibration device for obtaining a predetermined rotational angle position of the grinding worm on the profiling device in the profiling position is provided, for example in the form of a mandrel that can only be clamped in a defined rotational position and that supports the worm in the defined rotational position, or for example by a flat tangential plane area that is provided axially following the axial worm end and extends perpendicular to the radial direction on the worm rotation axis, and wherein the calibration device allows the orientation of the worm thread in the re-profiling area to be set in a predetermined direction (g) relative to a plane that extends perpendicular to the worm rotation axis via the rotation axis.

6. 6. The method of claim 5, wherein the profiling means has a region under tensile stress along this predetermined direction, said region extending longitudinally along this direction.

7. The method according to any one of claims 1 to 6, wherein continuously successive portions of the profiling means enter the material removal area, in particular in a continuously successive manner.

8. The method according to any one of claims 1 to 7, wherein the material removal is performed by electrical discharge machining, in particular by wire erosion.

9. A hard micromachined tool using a geometrically undefined cutting edge in the form of a grinding worm for the generating grinding of gears for the method according to any one of claims 1 to 8.

10. A method for reprofiling a grinding worm according to claim 9, comprising a step of removing material and a relative positioning therefor according to claim 1, and in particular one or more steps of characterization according to claims 2 to 8.

11. 10. A profiling device for profiling a grinding worm as embodied in accordance with claim 9, comprising a positioning device (20) having an axis of rotation (A) for positioning a profiling means relative to the orientation of the worm thread, and a liquid-filled receiving space for receiving, in particular, at least one area of ​​the grinding worm to be subjected to material removal and an abrasive area of ​​the profiling means (30).

12. 12. The profiling device according to claim 11, comprising a device (10) for rotating the grinding worm about its own axis of rotation and a further positioning system having at least two further degrees of freedom of movement for the relative position between the grinding worm and the profiling means, one degree of freedom having a component of movement in a plane extending perpendicular to the worm axis of rotation and another further degree of freedom having at least one directional component parallel to the worm axis of rotation.

13. 13. The profiling equipment device of claim 12, comprising a controller that, in an operating mode with a positioned rotation axis and a positioned rotation position of the grinding worm, allows relative movement along a zigzag path or multiple zigzag paths that include the two additional degrees of freedom of movement and correspond to the worm profile in an axial cross section.

14. 14. The profiling device according to claim 11, wherein in a second operating mode, the / a control device of the profiling device superimposes positioning (A0, Bm) and superimposed movements of a zigzag path or of multiple zigzag paths (δA, δB, δX, δY) in order to subject the surface of the worm thread to modifications, in particular profile angle modifications, profile line crowning, tooth tip and / or root relief, and imparts corresponding modifications on the ground workpiece during generating grinding with the grinding worm profiled in this modified way, the modification profiled on the grinding worm in particular comprising a coordinated superposition of these modifications, the modification comprising a correction to compensate for the additional profiling and the resulting changed central pitch diameter.

15. 15. Use of a profiling device according to any one of claims 11 to 14 for producing a grinding worm according to claim 9 by initial profiling thereof, wherein a grinding worm blank is machined by said profiling means, whereby said grinding worm thread is formed for the first time.

16. 11. The method according to claim 1, wherein a polygon-like surface structure in the circumferential direction of the generating grinding worm is created during re-profiling.

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