Method for cutting a gear, gear cutting tool and gear cutting machine

Abstract

A method for cutting a gear (4) from a metal workpiece (2), wherein the still oversize flanks of the gear compared to its predefined final geometry are hard finely finished in one or more cutting passes in cutting engagement with one or more cutting tools (10) fed thereto using a geometrically undefined cutting edge made of cutting grains incorporated in a binder matrix in order to produce a surface property thereof present in the final geometry; wherein in the cutting pass of the cutting tool (10b) a resiliently elastic mounting of the cutting grains by their binder matrix acts on the surface property and reduces the oversize cutting at the flanks by at least 2 µm by a compressive preload set by the cross feed of the cutting tool to which the cutting engagement is subjected to; and a gear cutting tool and machine tool for achieving this.

Description

[0001] The invention relates to a method for cutting a gear from a metal workpiece, in particular in continuous generating grinding, in which the still over-dimensioned flanks of the gear compared to its predefined final geometry are hard finely finished using a geometrically undefined cutting edge made of cutting grains incorporated in a binder matrix in one or more cutting passes in cutting engagement with one or more cutting tools fed thereto, in order to produce the reflective properties of its surface present in the final geometry, a gear cutting tool designed for this purpose, and a gear cutting machine designed for this purpose.

[0002] If a gear with a predetermined end geometry (target dimension) is to be produced, when the gear is cut, for example, in a soft cutting process, an over-dimensioning compared to the final geometry remains, which must then be removed by hard / fine finishing after the gear has been hardened. The hard / fine finishing can then be carried out by cutting with a geometrically defined cutting edge, for example, by hard peeling, but also by using a geometrically undefined cutting edge in a grinding process such as profile grinding, generating grinding, or skiving (hobbing).

[0003] For typical applications, such as for gears in the automotive industry, the over-dimensioning that still has to be removed can be 0.1 mm, i.e. about 100 pm, and in each case, using known techniques, this is removed in several cutting passes with deeper cross feed, by one or more roughing passes that remove most of the over-dimensioning, and then by one or more finishing passes that remove the residual over-dimensioning remaining after roughing to the final geometry. For the above example of 100 pm over-dimensioning, for example, 90 pm of over-dimensioning can be removed in a roughing pass, and the remaining 10 pm in a finishing pass.

[0004] For both roughing and finishing, the stiffness required for the cutting tools employed is usually achieved using ceramic bonds, for example, grinding worms for generating grinding; as to the abrasives, abrasive grains made of corundum or sintered corundum are often used, especially for cost reasons.

[0005] In addition, flank modifications such as crown or contraction can also be introduced by grinding. Both dressable and non-dressable grinding tools can be used. All of this is known to the person skilled in the art and is described, for example, in Thomas Bausch, Innovative Zahnradfertigung, 3rd edition, Expert Verlag.

[0006] By combining the above-mentioned roughing and finishing passes, it is possible to produce gears with a surface roughness in the range of about up to 2.5 pm (arithmetic mean roughness value R aa roughness depth of R z of the gear. After such a cut and with a roughness of these values, the surface appears matt. However, with the user, the requirements for a higher surface quality are increasing with a surface roughness which extends to the extent that the surface exhibits reflections.

[0007] In order to implement these additional requirements, the gears which have been prepared by roughing and finishing are subjected to polishing cuts which essentially only polish the gear surface to lower roughness values. A method of this type has been presented by the company Reishauer, for example, at the WZL Precision Machining Symposium in 2015 as a polishing grinding using elastic bonds in the area of grinding worm, which is carried out immediately after the conventional grinding cut without interrupting the cutting process and is only responsible for reducing the tip height of the roughness profile without changing the flank topography of the tooth flanks in the active area. For this polishing grinding, a roughness profile of R z 0.73 pm and R a 0.08 pm is specified as being achievable.

[0008] As another method principle, a so-called fine grinding phase was presented in the context of the same symposium, for which both the tip height and the groove depth of the roughness profile are reduced mainly by using finer grinding wheel grains by means of a grinding worm with a ceramic bond without changing the flank topography of the gear flanks in the active area. This fine grinding can be carried out in the finishing phase or in an additional cutting phase immediately after the conventional grinding without interrupting the cutting process, but the achieved roughness profile has an R z of only 1.35 pm and R a 0.21 pm and thus not the roughness parameters of the user specified target of R z less than 1 pm and R a less than 0.1 pm. The above-mentioned alternative of the polishing grinding presented by Reishauer achieves a significant improvement in the functional properties of the gear with relatively little effort. The reflective gear surface after the polishing is also easily recognizable on the exemplary workpieces presented. For both the polishing and the fine grinding, the change in surface finish is said to accumulate over time.

[0009] The object of the present invention is to further develop the method of the above-mentioned type in terms of achieving a satisfactory compromise between the gear surface quality and the process control.

[0010] This object is achieved by the invention by a method of the type mentioned above, which is essentially characterized in that, in the cutting pass of the cutting tool, the resiliently elastic mounting of the cutting grains fixed by their binder matrix exerts on the surface property and, by means of a compression preload, which is set by the cross feed of the cutting tool, the cutting engagement is subjected to this compression preload, the oversize cutting at the flank face is reduced by at least 2 μm.

[0011] The invention is based on the insight that, on the one hand, a satisfactory surface property is achieved and, on the other hand, it is possible to achieve advantages in the cutting itself, since, despite the surface property to be achieved and the resiliently elastic mounting of the cutting grains fixed by the binder matrix for achieving this, it is still possible to achieve a cutting reduction of the oversize on the flank face by setting a compression preload via the cross feed of the cutting tool. For various applications, this makes it possible to perform the cutting pass directly after (and only after) a roughing pass, so that, inter alia, a finishing pass can be omitted and, as a result, a shorter cycle time can be achieved, as will be explained in more detail below.

[0012] Within the meaning of the present disclosure, a surface has a reflective property if the average roughness depth R Z The surface has a reflective property if the average roughness depth R

[0013] In the present context, in a particularly preferred method design, in the cutting pass, the oversize is removed by more than 3 μm, preferably by more than 4 μm and, in particular, by more than 5 μm and / or by less than 12 μm, preferably by less than 10 μm and, in particular, by less than 8 μm. On the one hand, this allows a reduction in sensitivity, in particular when a roughing operation is performed beforehand. On the other hand, by not removing too much oversize, damaging influences due to a compression preload that is too great are avoided.

[0014] By setting the machine axis setting, a pressure preload can be achieved, for example, a higher radial cross feed of the tool against the workpiece (set to negative over diameter) compared to the setting that can be used to achieve the required over diameter removal in the case of less flexible tools. For example, for the reference indicated by the following values, a grinding worm can be used by which a pre-over diameter removal is carried out before the cutting pass of the cutting tool with the resiliently mounted cutting grains. Preferably, such an over feed of at least 20 pm, preferably at least 28 pm, and in particular at least 36 pm, and / or at most 100 pm, preferably at most 90 pm, in particular at most 80 pm, and in particular more preferably at most 70 pm, of such an over feed of the machine axis translates into such a reference-related radial over feed of the machine axis. The absolute values of the radial over feed can vary from machine to machine, since their resilient flexibility has to be taken into account. For the cutting tool with the resiliently mounted cutting grains employed, these have to be determined for the first time before initial use by the given machine configuration and workpiece configuration, or are retrieved accordingly from a data record, wherein these values from experimental tests or precise numerical simulations are stored in the data record.

[0015] With regard to the cutting grains or abrasive grains, a Knoop hardness (in N / mm 2 This ensures good cutting performance. If an individual cutting grain breaks, a "new" cutting edge also appears again, so that a satisfactory tool durability is achieved overall and in particular before the next required dressing is carried out to a satisfactory extent.

[0016] With regard to the cutting grains or abrasive grains, silicon carbide (SiC), in particular green or black, is preferred as a component and in particular as the main component. A grain blend with preferably at least 30%, more preferably at least 50%, and in particular at least 70% of SiC, in particular corundum / sintered corundum, is also considered as a further blend component.

[0017] The preferred grain size of the abrasive grains employed is in the range of greater than 5.5 pm, in particular greater than 7.5 pm, and more preferably greater than 8.5 pm, but on the other hand, they are preferably less than 18 pm, preferably less than 16 pm, and in particular less than 14 pm. According to the FEPA (Federation of European Producers of Abrasives) specification, for example, an abrasive grain size of 9.4 pm corresponds to the mesh fineness of a mesh of 600, and an abrasive grain size of 6.5 pm corresponds to a mesh of 800.

[0018] In terms of the material, it is preferred that the resilient adjustment comprises the selection of the material of the binder matrix, such as a plastic material or a rubber material, and in particular polyurethane.

[0019] The elasticity of a cutting tool with a resilient mounting element that incorporates cutting grains thus allows for movement within a certain range, within which, on the one hand, travel can still be achieved, and on the other hand, the minimum over-diameter reduction according to the invention is realized. In this context, it is particularly preferred that the elastic modulus (Young's modulus) of the cutting tool, measured in GPa, is less than 20.0, preferably less than 18.5, and especially less than 17.0 and / or greater than 10.0, preferably greater than 11.5, and especially greater than 13.0. The elastic modulus can be determined as part of an acoustic measurement, as has been used in quality inspection of gear cutting tools, for example, using... The measurement system. For this purpose, for example, a tool supported by three or four bearings is vibrated by an exciter, and the elastic modulus is determined by a sensor at a known density of the tool, which detects the tool's frequency response to the excitation (in tool inspection, this technique is used to detect tool damage while suppressing higher frequencies). The above values ​​apply to the tool used for that cutting pass (and only to that tool). If a combined tool is provided, for example, a combined tool designed for a cutting pass in one zone and for roughing in a related zone, and equipped with a ceramic bond for achieving this purpose, the measurement results of the combined tool produce a correspondingly higher elastic modulus value of close to 30 GPa for the overall bond, compared to the commonly used elastic modulus value of about 34 GPa for ceramic-bonded grinding tools. On the other hand, the elastic modulus of a pure polishing tool is only about 10 GPa to even less than 5 GPa, depending on its intended use.

[0020] Therefore, it is stipulated that softer tools than those typically used for roughing and finishing ceramic bonding parts should be used; however, on the other hand, harder tools than those used purely for polishing tasks should be used.

[0021] Regarding the average roughness depth (R) z The surface roughness, after this cutting pass, can be achieved and provided to be less than 1.2, preferably less than 1.1, more preferably less than 1.0 μm, and especially less than 0.9, measured in μm, and for the arithmetic mean roughness R... a This provides values ​​less than 0.12, and especially less than 0.10. Values ​​less than 0.08 can even be achieved (see below). Furthermore, it is preferred that the peak height R can be definitely reduced (via the Abbott curve). pk With core roughness depth R k The sum is less than 0.6 μm, even 0.5 μm or even 0.4 μm. For a reduced groove depth R... vk Ideally, R should not exceed the order of magnitude of the sum, but of course, it is also possible to assume that R...vk Value close to or exceeding core slot depth R k 50%.

[0022] Preferably, the cutting speed (v) measured in m / s for this cutting pass is specified. c The value is greater than 42, preferably 45, and especially 48 and / or less than 80, preferably less than 72, and especially 66.

[0023] As described above, in the specifically preferred method design, the cutting passes discussed so far are specified as subsequent cutting passes following the cutting operation (specifically roughing) that reduces the total oversize by more than 30 μm, preferably more than 50 μm, and especially more than 70 μm. In this context, it is also preferred that the preceding cutting comprises at most two cutting passes, and especially only one. In the latter, preferred variation, two cutting passes are sufficient for this purpose: a roughing cutting pass that, in this case, removes the total oversize preferably by more than 50 μm until the remaining oversize is used for the resilient mounting and compression preload cutting passes. Therefore, completely omitting the commonly used finishing passes saves significant cycle time.

[0024] When the total overdiameter to be removed is greater than 80 μm, 90 μm, or even 100 μm and / or the hardened initial gear exhibits severe asymmetry, a variant with two (roughing) passes is preferred. In this case, it is generally preferable that the two roughing passes provide at least approximately equal removal loads; in any case, each of the roughing passes should preferably remove overdiameter greater than 30 μm, especially greater than 40 μm. Cycle time can also be saved here by omitting the typically slow finishing steps.

[0025] Specifically, when the initial gear being transferred to hard finishing has low quality, such as concentricity error and / or total pitch error (each) being greater than 60% or even greater than 65% of the total over-diameter q, and especially even greater than 70%, when two cutting passes are performed before the cutting pass using a cutting tool with a resilient, elastic mount with cutting grains, a more asymmetrical removal distribution can also be provided between the first and second passes in these previous passes, resulting in less removal in the second pass of the previous cutting passes. In one possible implementation, for example, the average roughness depth R of the surface (to be obtained) after treatment with a cutting tool with a resilient, elastic mount with cutting grains. Z We can assume that the asymmetry factor Δq / q in the first or second pass (where Δq = |q1-q2| and q = |q1+q2|) and the removal of q1 and q2 are equal to or less than g2, where:

[0026] g2=0.6-[2 / (5π)]arctan[k(R Z [μm]-R0)],

[0027] Wherein, k = 80, R0 = 1.2, preferably R0 = 1.15, more preferably R0 = 1.1, even more preferably R0 = 1.05, and especially R0 = 1.0. Alternatively or otherwise, it is preferred that the ratio is Δq / q ≥ g1, where

[0028] g1=β[1-H(R Z [μm]-R'0)]

[0029] Wherein, R′0 = 1.0, preferably 1.05, and especially 1.1, and β = 0.4, preferably 0.5, and especially 0.6, and the Heaviside function H(x).

[0030] For typical applications of hobbing gears with a module range of less than 6 and a gear width of up to 150 mm, a correspondingly low cutting time can therefore be achieved in a preferred variant with only two cutting passes in total; in the design of a method with two passes and a springy mounting element, a satisfactory cutting time for achieving the desired final geometry can always be achieved, which in any case remains no higher than that using conventional processes.

[0031] In this context, it is preferable to set the ratio of the feed rate of subsequent cutting passes to the feed rate of previous passes to be greater than 1.4, preferably greater than 2, especially greater than 2.5, and even greater than 3. A ratio of 4 or higher is even conceivable. For adjusting the grinding tool, a common dressing system consisting of a forming roller and a contouring roller can be used. Flexible, tool-specific, or even multi-ribbed dressing tools should also be mentioned. Toothed dressers or radius dressers can also be used. In this case, the duration of adjustment can be similar to that of a common grinding process combining roughing and finishing strokes.

[0032] Furthermore, the present invention encompasses a suitably designed, preferably dressable, gear cutting tool for performing the method according to the invention. Specifically, the gear cutting tool may have at least two cutting zones, at least one of which is used for a preceding cut, and the other for a subsequent cut. These may be axially connected one after the other and, in particular, fixed to prevent rotation. Particularly preferred is the tool design for a grinding worm gear designed for continuous generating grinding, and of course, suitable tool designs are appropriate for other cutting processes as well.

[0033] Furthermore, the present invention covers a machine tool for cutting gears from a metal workpiece, the tool being equipped with control devices for performing the method according to the invention and / or a gear cutting tool of corresponding design, specifically, a grinding worm.

[0034] Further features, details, and advantages of the invention will become apparent from the following description with reference to the accompanying drawings, wherein

[0035] Figure 1 A schematic diagram of a forming grinding machine.

[0036] Figure 2 The axial section passing through the worm-shaped tool is schematically shown, and

[0037] Figure 3 a, Figure 3 b shows the Abbott curves for the two gears to be cut.

[0038] The following description further illustrates exemplary embodiments of the invention with respect to continuous generating grinding. A grinding mill suitable for achieving this purpose has a workpiece spindle or table spindle 80 mounted in a machine bed 40, on which a workpiece wheel 2 is clamped. This workpiece wheel is pre-toothed and has a gear 4. The type of workpiece wheel 2 and gear 4 is not further limited. A cylindrical wheel is shown, but the invention is not limited thereto, and other types of gears can also be cut. For wavy workpieces, a tailstock can be provided to achieve this purpose. Figure 1 (Not shown in the image).

[0039] In terms of tooling, a bracket assembly is provided that holds and positions the cutting tool 10, which is in the form of a grinding worm. Specifically, as... Figure 1 As shown, three linear motion axes X, Y and Z are provided, which can adjust the relative position of tool 10 with respect to workpiece wheel 2 by the CNC-controlled machine axis movement of controller 99.

[0040] A linear support 50 is configured for radial (X) feed motion. The latter carries a vertical support 60 for extending the machine axis Z parallel to the workpiece rotation axis C. Another support 70 is rotatably arranged relative to the vertical support 60; in this case, rotation occurs along the X-axis direction (rotation axis A). Support 70 also includes a tangential support (Y-axis) by which the tool 10 can be displaced along the tool rotation axis. Figure 1 When the pivot angle A = 0 as shown in the figure, the tool rotation axis is along Figure 1 The rectangular coordinate system X, Y, Z shown extends in the Y direction. The axis of rotation of the tool around its own axis is labeled B as the axis of rotation, and the axis of rotation of the workpiece is labeled C as the axis of rotation.

[0041] As stated above, this design can therefore be a known structure of generating grinding machines, and correspondingly, other constructive designs and machine axis distributions can be alternatively provided.

[0042] Figure 2 The worm-shaped tool 10 schematically shown is a combination tool with two coaxial segments 10a and 10b, which are connected in a rotationally fixed manner in this exemplary embodiment. In this exemplary embodiment, segment 10a is a grinding worm designed for roughing gears in a continuous generating grinding method, specifically using ceramic bonding, which is also well known in the prior art. In this exemplary embodiment, the other segment 10b is also a worm-shaped tool, which can be, and is similar to, segment 10a, especially with respect to worm parameters. The width of 10b corresponds to the minimum engagement width between tool 10 and gear 4, and the maximum value of half the width of the grinding wheel (10a = 10b), typically in the range of 60 mm.

[0043] In this exemplary embodiment, the elastic modulus of segment 10b is 13.6 GPa when measured alone. Furthermore, in this exemplary embodiment, the binder matrix is ​​formed of polyurethane material, and the abrasive grains are made of green silicon carbide. As will be explained in more detail below, segment 10b of the screw 10 is used to machine the rough-machined gear 4 into a final geometry with the desired surface properties without requiring intermediate finishing passes for material removal (intermediate finishing passes are typically performed, for example, using segment 10a of the worm gear 10).

[0044] To this end, the over-diameter relative to the final geometry is first removed in one or more roughing passes to achieve a residual over-diameter of up to, for example, 6 μm in this embodiment. This residual over-diameter is thus much smaller than the over-diameter typically left during roughing for subsequent finishing passes (typically, finishing processes remove approximately 20 μm of material). Subsequently, the worm segment 10b is used without performing finishing passes to remove the remaining residual over-diameter in only one cutting pass to obtain the final geometry in this exemplary embodiment. The worm segment 10b is engaged with the gear 4 in a continuous generating grinding cutting operation at a higher radial (X) feed than required to achieve the final geometry with a non-elastic tool such as segment 10a. Because the worm segment 10b is designed to be elastic in this way and the preload is set to a negative over-diameter, only material is removed until the final geometry is obtained, due to the elastic nature of the tool segment 10b, while also providing a high surface quality. Furthermore, compared to pure polishing, more significant material removal is achieved compared to conventional polishing because the cutting tool remains harder.

[0045] Two specific exemplary implementation schemes are described below.

[0046] In the first embodiment, a gear with a module of 3 mm, 22 teeth, and an engagement angle of 20° is ground. This gear has helical teeth with a helix angle of 20°. The gear width in this embodiment is 34 mm. The outer diameter and root circle diameter of the exemplary embodiment are 76.77 mm and 62.50 mm, respectively. The pre-cut dimension, using a double-sphere diameter of 6 mm as a measuring sphere, prior to hard finishing, is 81.150 mm, and the final dimension corresponding to the final geometry is 80.605 mm, resulting in an oversize of 125 μm on each side.

[0047] Grinding tools are like Figure 2 The two-part tool shown is, in this embodiment, a three-head grinding worm with an engagement angle of 20°.

[0048] The cutting speed is set to 50 m / s, and the cutting strategy is a three-pass grinding strategy, in which the two roughing passes use worm region 10a and the final pass uses worm region 10b.

[0049] In this specific exemplary embodiment, the radial cross feed is initially 0.237 mm in the first roughing pass and subsequently 0.179 mm in the second roughing pass. The radial cross feed setting for the machine in the third cutting pass remains 0.070 mm. (The numbers in mm are listed in the order of stroke sequence.) 3 The nominal material removal rate Q is expressed in units of [ / s]. w The feed rates are 65.5, 43.7, and 43.4 mm per revolution; 0.273, 0.241 mm per revolution for the same transverse feed in the same order, and finally 0.846 mm per revolution. Therefore, the transverse feed in the final cutting pass is significantly higher than that in the preceding roughing passes. This allows for a shorter overall cutting time and a correspondingly significantly better cycle time compared to the conventional method of inserting another finishing pass after roughing.

[0050] The Hommel-Etamic Turbowave V7.60 (probe TKU 300, measurement range 400μm, scanning distance L) was used. t The length is 4.80 mm, and the speed (V) is 4.80 mm. t The velocity was 0.5 mm / s. Using a filter conforming to ISO 11562, 24,000 measurements were recorded for the PRW profile, where L... c (Cutoff) is 0.800mm, L c / L sFor example, the surface quality of gear 4 machined in this manner is measured by an OFF probe (r = 5 μm / 90°).

[0051] Determine the R-profile (Abbott curve) for the material segment. Figure 3 The curve shown in section a (right side); surface characteristic value R a =0.09μm, R z =0.71μm.

[0052] In a second exemplary embodiment, a two-stroke strategy is used, with each stroke employing worm segment 10a and worm segment 10b respectively. In this case, the gear data is: module 1.275mm, 36 teeth, engagement angle 18°, helix angle -22°, gear width 16.6mm, outer diameter 51.98mm, and root circle diameter 45.40mm.

[0053] Here, the pre-cut dimension of 53.803mm (by diameter, measuring the double-ball dimension M with a ball diameter of 2.5mm) is used. dk The material is removed to a final dimension of 53.275 mm (corresponding to an over-diameter of 0.099 mm on each side). The tool used here is a five-head grinding worm with an engagement angle of 18°; the cutting speed remains unchanged compared to the first exemplary embodiment.

[0054] Other process parameters set for strokes 1 and 2 are as follows: the machine axis settings for radial transverse feed are 0.306 mm and 0.065 mm, respectively, and the workpiece feed per revolution is 0.227 mm and 0.948 mm, respectively. The nominal material removal rate is 45 mm / s. 3 / s or 40mm 3 / s.

[0055] The tooth system machined in this manner was also measured, with variations in the sensing distance (1.50 mm), speed (0.15 mm / s), and L. c The measurement parameter is 0.250 mm.

[0056] In this way, R is determined a The value is 0.07 μm, and R is determined. Z The value is 0.51 μm. Figure 3 Figure b shows the Abbott curve used for the same right-side face. Furthermore, the core roughness depth R was determined. k The diameter is 0.22 μm, and the tip height is reduced by 0.08 μm, as is the groove depth R. vk It is 0.11 μm.

[0057] Therefore, in both exemplary embodiments, surface quality can be achieved and even exceeded the user's requirements. Nevertheless, it is preferable to use a ceramic bonding section (worm section 10a) to eliminate general finishing passes by pre-cutting tools, thereby achieving favorable cutting time.

[0058] Furthermore, the present invention is not limited to the embodiments explicitly depicted in the preceding description. Rather, the various features described above and in combination with those in the following claims may be necessary for carrying out the invention in its various embodiments.

[0059] Although the invention has been described in more detail in specific embodiments of continuous generating grinding, the machining mechanisms and features described in the introduction can also be applied to other hard precision machining methods for gears.

[0060] Tools used for roughing and cutting via elastic mounting and compression preloading are not necessarily like... Figure 2 The combination tools shown can be used to achieve this; alternatively, individual tools clamped together in the grinding head can be used, or they can be set in separate grinding heads, as can be achieved using tools such as... Figure 1 Other grinding mechanism shapes are shown in the figure.

Claims

1. A method for cutting a gear (4) from a metal workpiece (2), the method comprising: In continuous generating grinding, in which the tooth flanks of the gearwheel (4) still have an overradius compared to their predefined final geometry, the tooth flanks of the gearwheel (4) are, in one or more cutting passes in cutting engagement with one or more cutting tools (10) fed thereto, hard-fine finished using a geometrically undefined cutting edge made of cutting grains incorporated in a binder matrix, in order to produce the reflective properties of their surfaces which are present in the final geometry, characterized in that in the cutting pass of the second cutting zone (10b), the resiliently elastic mounting of the cutting grains fixed by their binder matrix all act on the tooth surface to produce the reflective properties, and the overradius at the tooth flanks is reduced by at least 2 µm by a compressive preload set by the cross feed of the cutting tool, the cutting engagement is subjected to the compressive preload, and the compressive preload is achieved by a radial overfeed of at least 20 µm and / or at most 100 µm, corresponding to a negative overradius beyond the final geometry in relation to a reference.

2. The method of claim 1, wherein, In the cutting pass, an overradius of more than 3 µm is removed and / or an overradius of less than 12 µm is removed.

3. The method of claim 2, wherein, In the cutting pass, an overradius of more than 4 µm is removed.

4. The method of claim 2, wherein, In the cutting pass, an overradius of more than 5 µm is removed.

5. The method of claim 2, wherein, In the cutting pass, an overradius of less than 10 µm is removed.

6. The method of claim 2, wherein, In the cutting pass, an overradius of less than 8 µm is removed.

7. The method of any one of claims 1 to 6, wherein, The material of the binder matrix is selected to be a plastic material or a rubber material.

8. The method of any one of claims 1 to 6, wherein, The material of the binder matrix is selected to be polyurethane.

9. The method of any one of claims 1 to 6, wherein, A value of less than 20.0 and / or more than 10.0 measured in GPa is used for the modulus of elasticity of the cutting tool.

10. The method of claim 9, wherein, The value of less than 18.5 is used.

11. The method of claim 9, wherein, The value of less than 17.0 is used.

12. The method of claim 9, wherein, The value of more than 11.5 is used.

13. The method of claim 9, wherein, The value of more than 13.0 is used.

14. The method of any one of claims 1 to 6, wherein, The compressive preload is achieved by a radial overfeed of at least 28 µm, corresponding to a negative overradius beyond the final geometry in relation to a reference.

15. The method of any one of claims 1 to 6, wherein, The compressive preload is achieved by a radial overfeed of at least 36 µm, corresponding to a negative overradius beyond the final geometry in relation to a reference.

16. The method of any one of claims 1 to 6, wherein, The compressive preload is achieved by a radial overfeed of at most 90 µm, corresponding to a negative overradius beyond the final geometry in relation to a reference.

17. The method of any one of claims 1 to 6, wherein, The compressive preload is achieved by a radial overfeed of at most 80 µm, corresponding to a negative overradius beyond the final geometry in relation to a reference.

18. The method of any one of claims 1 to 6, wherein, the cutting grains of the cutting pass in N / mm 2 are greater than 23000.

19. The method of any one of claims 1 to 6, wherein, the cutting grains of the cutting pass in N / mm 2 are greater than 25000.

20. The method of any one of claims 1 to 6, wherein, the cutting grains of the cutting pass in N / mm 2 are greater than 27000.

21. The method of any one of claims 1 to 6, wherein, The cutting speed (v) measured in m / s for this cutting pass. c (42 and / or less than 80) 22. The method of claim 21, wherein, The cutting speed (v c ) is greater than 45 m / s.

23. The method of claim 21, wherein, The cutting speed (v c ) is greater than 48 m / s.

24. The method of claim 21, wherein, The cutting speed (v c ) is less than 72 m / s.

25. The method of claim 21, wherein, The cutting speed (v c ) is less than 66 m / s.

26. The method according to one of claims 1 to 6, wherein, The grain size of the cutting grains is in the range of more than 5.5 µm and / or the grain size is less than 18 µm.

27. The method of claim 26, wherein, The grain size of the cutting grains is in the range of more than 7.5 µm.

28. The method of claim 26, wherein, The grain size of the cutting grains is in the range of more than 8.5 µm.

29. The method of claim 26, wherein, The grain size is less than 16 µm.

30. The method of claim 26, wherein, The grain size is less than 14 µm.

31. The method of any one of claims 1 to 6, wherein, After the cutting pass, the average roughness depth (R z ) of the surface, shown in µm, is less than 1.

2.

32. The method of any one of claims 1 to 6, wherein, After the cutting pass, the average roughness depth (R z ) of the surface, shown in µm, is less than 1.

1.

33. The method of any one of claims 1 to 6, wherein, After the cutting pass, the average roughness depth (R z ) of the surface, shown in µm, is less than 1.

0.

34. The method of any one of claims 1 to 6, wherein, After the cutting pass, the average roughness depth (R z ) of the surface, shown in µm, is less than 0.

9.

35. The method of claim 1, wherein, The cutting pass is a subsequent cutting pass immediately after a cutting operation which in one or more cutting passes reduces the overradius by more than 30 µm in total.

36. The method of claim 1, wherein, The cutting pass is a subsequent cutting pass immediately following a cutting operation that reduces the oversize by more than 50 pm in total in one or more cutting passes.

37. The method of claim 1, wherein, The cutting pass is a subsequent cutting pass immediately following a cutting operation that reduces the oversize by more than 70 pm in total in one or more cutting passes.

38. The method of any one of claims 35-37, wherein, The preceding cutting comprises two cutting passes.

39. The method of any one of claims 35-37, wherein, The preceding cutting comprises only one cutting pass.

40. A gear cutting tool (10) for hard fine finishing of a gear (4), the gear cutting tool being designed for use in a method according to any one of claims 1 to 39.

41. The gear cutting tool according to claim 40, the gear cutting tool having a first cutting area (10a) for a cutting operation and a second cutting area (10b) for a cutting pass following the cutting operation.

42. The gear cutting tool according to claim 40 or 41, the gear cutting tool being in the form of a worm designed for generating grinding.

43. A machine tool (100) for cutting a gear from a metal workpiece, the machine tool having a control device (99) that controls the machine tool to perform a method according to one of claims 1 to 39 and / or having a gear cutting tool (10) according to one of claims 40 to 42.

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