A method of generating or machining a set of identical teeth on each of a plurality of workpieces by cutting, as well as a group of machines and a control program therefor

Abstract

The present invention relates to a method for producing or machining, by cutting, a plurality of workpieces of a workpiece batch, in particular at least four workpieces, each having an identical set of teeth, on one or more gear cutting machines (100) having a gear cutting tool (S) with a set of teeth having a rake face (5) and having an axis of rotation (B1) in a rolling-machining mesh, wherein, if deviations of the set of teeth from a desired tooth profile for the set of teeth are detected or predicted, measures are determined to counteract the deviations and the production / machining of further workpieces of the workpiece batch is continued using the measures, the measures being, at least in part, a change in the position of the rake face relative to the axis of rotation of the tool, the change being brought about by grinding performed on the gear cutting machine or on a grinding machine (140) belonging to the machine family of the gear cutting machine.

Description

Technical Field

[0001] The present invention relates to a method for producing or machining a plurality of workpieces in a workpiece batch, in particular each of at least four workpieces, with the same set of teeth by cutting the same set of teeth having a set of teeth with a rake face in a gear cutting tool and having a rotational axis in a rolling machining engagement, wherein if a deviation of the set of teeth from the tooth profile required for the set of teeth is detected or predicted, a countermeasure for canceling the deviation is determined and the countermeasure is used to continue the production / machining of additional workpieces in the workpiece batch.

Background Art

[0002] Such methods and countermeasures are known. It is possible that a gear cutting tool designed for the teeth of a specific workpiece gear does not accurately generate the required tooth profile of the workpiece gear, which may occur repeatedly. For example, during skiving on the left and / or right tooth surfaces of a set of teeth, a profile angle deviation that is too high is determined, for example, by measuring the first workpiece or a plurality of first workpieces in a workpiece batch. When the number of workpieces is small, countermeasures can be considered only during hard precision machining after hardening each workpiece, but this places a significant burden on subsequent hard precision machining, especially in the case of a larger workpiece batch, and in some cases, it becomes difficult to compensate if the deviation is too large.

[0003] Therefore, in order to bring these subsequent workpieces closer to the desired tooth profile, it is more accurate in the case of a larger workpiece batch to technically respond during the machining itself by means of the countermeasures already used for machining subsequent workpieces in the workpiece batch.

[0004] For this purpose, the flexibility and machining accuracy of the latest CNC controlled gear cutting machines are used by setting the correction of the machining intervention that cancels out the detected deviation by means of machine axis correction. For example, in the case of gear hobbing, the swivel axis of the hobbing machine can be set to the corrected crossing axis angle of the tool rotation axis relative to the workpiece rotation axis, or the offset of the machining position can be set using, for example, a tangential carriage. For details regarding the relationship between these conditions during hobbing, reference is made to EP2537615A1, which this application quotes regarding these aspects, the cutting conditions of hobbing and the kinematic characteristics. This enables a very flexible correction method, and thus a corresponding controller that independently calculates the necessary machine axis changes is implemented in the latest CNC machines manufactured by a number of manufacturers.

Summary of the Invention

[0005] The object of the present invention is to further improve the method of the type described at the beginning, particularly with regard to a satisfactory combination of flexibility and tool service life.

[0006] This object is achieved according to the invention from the point of view of process technology in that the measure is, at least in part, a change in the position of the rake face relative to the tool rotation axis, which change is brought about by grinding carried out in a gear cutting machine or in a grinding machine belonging to the machine group of the gear cutting machine.

[0007] Thus, the present invention shifts part of the measure, particularly the main part, from dynamic correction to a structural change of the tool, specifically to a change in the relative position of the rake face relative to the tool rotation axis. These rake faces according to the invention, preferably planar rake faces, are determined by the step angle, i.e. the inclination of the rake face with respect to the plane orthogonal to the tool rotation axis when viewed in the circumferential direction, and in some cases by the tip rake angle at a non-zero angle, i.e. the inclination of the rake face with respect to this plane in the radial direction with respect to the tool rotation axis, at their position with respect to the tool rotation axis in the typical design of a step-cut cutting wheel.

[0008] According to the present invention, the position or positional orientation of this rake face is changed by regrinding at a predetermined position. The gear cutting tool preferably remains clamped to the gear cutting machine itself for regrinding. In the method according to the present invention, the dynamic correction described above is no longer necessary, or at least not to such an extent, in order to bring other workpieces of the workpiece batch closer to the desired tooth profile, since the gear cutting tool is used as it is with a machine axis setting close to the machine axis setting for which the tool was designed with the selected cone angle for the gear cutting tool, and thus, in the most favorable case, it means that the effective relief angle is maintained as a whole. This prevents the process forces, which have been recognized as a factor increasing the load on the gear cutting tool and accordingly shortening the tool life, from shifting over the life of the gear cutting tool.

[0009] However, the flexibility of the method is maintained by regrinding the gear cutting tool at a predetermined position, although this includes tolerating the time and machinery required for regrinding.

[0010] The method is suitable for smaller workpiece batches having 4 or more, 10 or more, and even 20 or more workpieces, and for larger workpiece batches having 50 or more, and even 100 or 200 or more workpieces.

[0011] There can be various reasons for situations in which it can be decided to regrind the gear cutting tool. It can correct defects occurring during the normal service life of the gear cutting tool, but also, for example, if a tendency for hardening distortion that needs to be compensated in advance is recognized, or for example in other cases where there is room to better approximate the desired tooth profile, for example to cope with a desired tooth profile that is different from the tolerance values in addition to the intended final shape.

[0012] The gear cutting tool is preferably a cutting wheel, i.e., in particular, a skiving wheel for skiving a set of teeth that have already been pre-cut and hardened after pre-cutting, or a skiving wheel for hard skiving, or a form cutting wheel for form cutting the teeth of a gear. Hard metal or powder metal high speed steel (PM-HSS) materials can be used as the base material, but other materials can also be used. In some cases, wear-resistant strengthening coatings such as any other coating common to those skilled in the art, such as Al, CrN, or TiN, can be provided.

[0013] In a preferred embodiment of the method, it is provided that the gear cutting tool no longer receives a coating with a wear-resistant strengthening layer between its grinding process and the continuation of its use, as is otherwise customary in the art, for example, after mere regrinding. In this way, the time-consuming coating process is no longer expected and no longer has an impact on time delay. Overall, the gear cutting tool tends to be ready to be reused quite quickly after regrinding, and in particular, it is preferably used within at least 24 hours, more preferably within 12 hours, and even more preferably within 6 hours. If a plurality of identical gear cutting tools are available, after regrinding, processing can be continued using one of these same tools.

[0014] The use of the gear cutting tool preferably continues on the very same gear cutting machine, but in a larger system having a plurality of, in particular, identical gear cutting machines that process the same type of workpiece batch in parallel, the use can also continue on such parallel machines.

[0015] In a preferred embodiment of the method, the rake face is ground to a modified tip rake angle during grinding, i.e., the tip rake angle is changed by regrinding. A decrease in the tip rake angle causes an increase in the profile angle or pressure angle of the tooth profile of the workpiece tooth portion, while an increase in the tip rake angle, conversely, leads to a decrease in the profile angles of both tooth flanks of the workpiece tooth portion (when operating in the two-flank method). Thus, regrinding in this regard is particularly suitable for correcting or influencing the deviations that occur mainly symmetrically on the left and right tooth flanks of the workpiece tooth portion.

[0016] Furthermore, alternatively or additionally, it is preferably provided that the grinding or regrinding is carried out at a modified step angle during the grinding process. This results in an asymmetric effect on one tooth flank and the other tooth flank of the workpiece tooth portion. For example, if the step angle is reduced to increase the profile angle on the left tooth flank, this will not increase but rather decrease on the right tooth flank side (in the two-flank method). Thus, the asymmetric part of the profile error with respect to the deviations on the left and right tooth flanks is preferably cancelled by modifying the step angle.

[0017] For the sake of simple illustration and explanation, if the deviation of the profile angle on the left tooth flank of the workpiece tooth portion is +5 and on the right tooth flank is +1, for example, a correction of the step angle of -2 and a correction of the tip rake angle of -3 can be made with respect to the left tooth flank. On the left tooth flank, these corrections are additive, cancelling the profile angle deviation of +5 to -5, and on the right tooth flank, the correction of the step angle cancels the correction of the tip rake angle, thus a total correction of -1 also compensates for the profile angle deviation of +1.

[0018] The method according to the invention can also include, as an additional measure, the dynamic correction described above. Thus, the measures are clearly intended to include, in addition to changing the relative position of the rake face, the generation / machining of the teeth of the gear, or the dynamic correction in the form of the movement of the machine axis corrected compared to the originally intended generation / machining of the teeth of the gear having the detected deviation or the deviation to be detected. This example, which can also be used for this further development of the invention, has already been described in the preamble of this specification.

[0019] In this connection, it is preferred that the dynamic correction is given to be calculated independently by a controller that controls the machine axis for the machining operation, depending on the corrections made to the rake face. For example, the operator of the machine receives from the controller of the machine a correction value or target value for the regrinding of the gear cutting tool calculated from the deviation from the tooth profile required when the measures to be taken are identified. Then, an appropriately controlled regrinding task can be assigned to the grinding machine semi-automatically or automatically. However, it is also conceivable that the operator determines a less regrinding that only partially corrects the deviation, and the remaining deviation is carried out via dynamic correction.

[0020] It is also conceivable that the entire deviation is corrected via regrinding, but the need for correction to be dynamically corrected is perhaps detected at a later point in time. In this case, the gear cutting machine uses the previously regrinded tool profile as a basis for determining the necessary machine axis correction, rather than the original tool profile before regrinding.

[0021] As already shown above, the regrinding of a gear cutting tool can be carried out on a grinding machine belonging to the machine group of the gear cutting machine, for example a grinding machine that is mechanically connected to the gear cutting machine in a machine combination. In any case, if the controller is provided separately, it is preferably connected in order to enable data exchange regarding the regrinding parameters described above. In a preferred embodiment, the gear cutting tool can be brought to the grinding machine via a tool changing system or by some other means. In an even more preferred embodiment, in the case of a gear cutting machine that processes at least the workpiece batch individually, the gear cutting tool can be reground without having to unclamp it from the tool head of the gear cutting machine. In a preferred method configuration in this regard, the machine axes of the machining intervention can be used to position the gear cutting tool during its grinding operation.

[0022] Regarding device technology, the invention is protected by a corresponding machine group having a controller according to the above aspects, as well as by the control program itself.

[0023] The advantages of the technical implementation according to the invention result from the advantages of the method aspects described above.

[0024] In an additional aspect, the grindability at a given position can be used to regrind the gear cutting tool, i.e., the position of the rake face relative to the tool rotation axis remains unchanged, rather, only their height relative to a reference point on the tool rotation axis changes, and a grinding process of the rake face can be carried out.

Brief Description of the Drawings

[0025] Further features, details, and advantages of the present invention can be found in the following description with reference to the accompanying drawings.

Figure 1

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Figure 8B

Figure 9A

Figure 9B

BEST MODE FOR CARRYING OUT THE INVENTION

[0026] The machine tool shown in FIG. 1 is a machine 100 designed to perform skiving using a skiving wheel S. On the workpiece side, the machine 100 has a tool table 80, and the tool table 80 is attached to the machine bed 90 in a rotation drive manner, and a workpiece (not shown in FIG. 1) having, for example, an internal tooth portion to be machined can be clamped so as to be rotatable around the machine rotation axis C1 on the tool side.

[0027] On the tool side, the machine 100 has a linear machine axis X1 for the radial positioning movement of the tool relative to the workpiece, an axis Z1 for the movement of the tool along the axial direction of the table axis C1, and an axis Y1 for the tangential relative movement between the tool and the workpiece. These linear axes X1 and Z1 are perpendicular to each other, and the linear carriage 72 for X1 movement is implemented via a carriage configuration 70 that carries the vertical carriage 74 for Z1 movement. In this embodiment, the tool head 78 that carries the tool S and also carries a CNC drive as a direct drive for tool rotation having a rotational axis B1 can move together with the linear carriage 76 for tangential movement Y1. However, the tangential carriage 76 is rotatably arranged with a swivel axis A1 on the vertical carriage 74, and thus, the movement of the carriage is only in the horizontal direction at the position shown in FIG. 1 and otherwise is inclined with respect to the Z1 axis by the set swivel angle A1.

[0028] The gear cutting machine 100, together with the grinding machine 140 also shown in FIG. 1, forms a machine combination 200. The grinding machine 140 can also have its own clamping part for the tool to be reground, but the clamping part held by the tool spindle of the gear cutting machine 100 is preferred.

[0029] Grinder 140 has a movement system that can grind the grinding tool M against the skiving wheel S clamped to the tool clamping part of the tool head 78. The linear and rotational axes on the tool side can also be used (can be) to generate the grinding engagement. In the illustrated embodiment, the grinding tool M, which is configured in the form of a cup wheel in this embodiment, is movable in the tangential direction Y perpendicular to the X1-Z1 plane. Therefore, it can be introduced into the machining space laterally with respect to the radial direction X1. This movement in the Y direction is implemented by the double carriages 41, 42, of which the lower carriage 41 is provided for positioning about the axis Y3, while the upper carriage 42 is provided for the upward movement in the grinding operation. Further, a grinding spindle 44 that carries the grinding tool M and is rotationally driven about the axis D1 is arranged to be swiveling (the swivel axis is indicated by A2) in a plane perpendicular to the Y direction. Therefore, the angle ξ is formed between the axial direction of the rotation axis D1 and the axis Z1 (C1) in a plane parallel to the X1-Z1 plane.

[0030] The Y1 axis of the tool head 78 (possibly combined with Z1) is used for the grinding stroke motion, and in some cases, a modified form in which axes on the grinding head such as Y2 are preserved is also conceivable. Further, an additional axis X2 of the grinding head parallel to the X1 direction, or a further swivel axis having a swivel axis X2, is also conceivable.

[0031] For a workpiece that has already been machined by the skiving wheel S (for example, by measuring with a tooth part tester not shown), if it is determined that its tooth profile deviates from a predetermined desired tooth profile, this is a signal. In this embodiment, it is determined that further workpieces of the same workpiece batch will only be machined after the skiving wheel S is corrected to cancel out the detected profile deviation. The controller (not shown) of the machine combination 200 calculates the changes (in the step angle and / or the tip relief angle) required for the orientation of the rake face of (their normal vectors), and the grinder 140 performs a grinding operation on the skiving wheel S to correct it according to these specifications.

[0032] This will be described below for a skiving wheel S implemented by step grinding (see also FIG. 2) and having a non-zero tip relief angle. In this case, the grinding tool M is pivoted to the modified step angle of the skiving wheel S using the pivot axis A2. The pivot axis A1 of the skiving wheel S is pivoted to the modified tip relief angle of the skiving wheel S. In this setting, the relief face 5 to be reground (by the indexing method), the center line of the relief face 5 facing the side of the grinding tool M runs horizontally at a position 90° with respect to the radial axis X1. During the grinding stroke motion (axis Y2), then, the machining area moves along the relief face 5 during the grinding stroke, and the orientation of the grinding area of the cup wheel M coincides with the orientation of the modified relief face, and thus the relief face 5 can be reground accordingly. The Z1 axis of the skiving wheel S can be used for adjusting the height of the machining engagement and the feed, while the XY machine axes are used for positioning, needless to say.

[0033] By feeding the grinding tool M laterally with respect to the radial axis X1, the competing space requirements on the machine side are avoided. Also, since the grinding stroke and the feed direction are parallel, vibrations during regrinding are significantly avoided. When all the relief faces 5 are continuously reground in this way by the indexing process, the grinding tool M can be retracted and the gear machining by the skiving wheel S can be resumed and continued.

[0034] Changes resulting from the modified shape of the skiving wheel due to regrinding are automatically adopted in the machine controller. The machine controller has all the necessary information derived from the original tool design stored there and the knowledge of the cutting performed during regrinding via the axial position of the machine axes used in this process. If it is determined that the corrective measures are only due to regrinding, continuous machining is performed using the same machine axis controller as before. However, it is also possible to provide for correcting only a part (especially the main part) of the necessary countermeasures by regrinding. In this case, the machine controller automatically calculates the correction components not yet taken into account according to the data of the regrinded tool and, with respect to this correction component, performs dynamic correction as is customary in the prior art, for example by changing the machine axis settings for the machining engagement by means of a modified swivel setting (axis A1) or eccentricity (axis Y1).

[0035] However, in an alternative embodiment, for example, when the side surface of the tool is ground closest to the main machine stand (70) (e.g., 0° position for the internal tooth portion) or farthest from the main machine stand (70) (e.g., 180° position for the external tooth portion), the grinding stroke can also be performed in the X1 machine direction. In this case, preferably, the swivel axis setting of the tool head 78 is left set to the machining axis intersection angle. For example, when the workpiece machining is for an internal tooth portion where the work is performed at the 0° position, in order to set the rake face 5 horizontally, the 180° position can be set to twice the opposite axis intersection angle. However, it is also conceivable that the axis intersection angle is not changed in this way or left as it is at the machining position. Then, the grinding head (44) can be provided to receive an additional swivel axis, and it is also conceivable to use a highly conical outer surface as the grinding wheel instead of being designed as a cup wheel. When there is no tip rake angle, it is necessary to regrind the rake face running horizontally in the radial direction, and in the case of an existing tip rake angle, for example, by an additional movement of the machine axis Z1, the regrinding contact can be maintained. For this purpose, when using a cup wheel, the axis A2 (FIG. 1) can be swiveled to the tip rake angle, and the swivel axis A2 of the regrinding head is set to the same orientation as the surface to be ground in the machining operation.

[0036] In this variant, in order to avoid space interference with the workpiece table 80, it is preferable to perform regrinding on the side of the tool S closest to the main machine stand (carriage configuration 70). Since the tool head 78 does not need to be pivotally inserted via the pivot axis A1, this is particularly important when machining internal tooth portions. In the case of external tooth portions, if there is no intention of pivotally inserting via the pivot axis A1, regrinding needs to be performed at the 180° position. At the 180° position, there are conditions of available installation space that are often more advantageous. In particular, when the skiving wheel S does not have a tip relief angle, it is considered to use the rotational movement of the grinding tool M via the spindle (machine table 80 in a configuration similar to FIG. 1) that holds the workpiece during machining, and it is also possible to execute the grinding stroke via the radial axis X1. This variant allows for a non-zero tip relief angle by using the radial axis X1 for the grinding stroke and an adjusted offset of the engagement area (with respect to the 0° position) by the superimposed movements Y1 and Z1.

[0037] The superimposed variant in which the grinding stroke is performed in an oblique direction (i.e., having an X-direction component and a Y-direction component) can be implemented around the existing machine axes of the machine configuration shown in FIG. 1 for the skiving wheel S and for the cutting tool M. Then, it is preferable that the pivot axis (A1 axis) of the skiving wheel S is set according to the grinding stroke direction and the angle ξ set for the grinding tool M that is suitable for the modified head relief angle.

[0038] Depending on the dimensions of the grinding tool M used, it is also conceivable to completely omit the realization of the grinding stroke, i.e., when the relief surface 5 is already completely covered. Then, regrinding becomes plunge grinding.

[0039] In order to accurately determine the relative position between the skiving wheel S and the grinding tool M, it is possible to probe the skiving wheel S together with the grinding tool M in the axial and circumferential directions in order to determine the exact relative height and relative angular position of the teeth of the tool S with respect to the grinding tool M. This is shown to be the case particularly after a change of the machining tool S and / or the grinding tool M. This is because by swiveling the grinding head 78, it is possible to keep the tool S at the machining axis intersection angle. However, the angular position of the teeth 4 of the tool may already be known for previous machining and monitoring of the machine axis B1. For example, noise detection can be used for contact detection so that the machine axis can be monitored via changes in the torque of the tool or workpiece spindle (B1 / C1). Visual detection methods such as spark detection can also be used.

[0040] Such probing is also preferred when the grinding tool M itself has received alignment work. It can be carried out completely automatically, i.e., the machine combination 200 can perform the probing independently, or semi-automatically with the operator making a rough pre-positioning, or, when the operator controls the probing via the machine's user interface, guided by the software. A purely manual variant by using manual control to probe through the movement of the axis is also conceivable.

[0041] For example, if a skiving wheel without step grinding is used, a continuous process for regrinding can be used in addition to an intermittent process, for example using a cup wheel.

[0042] When generating a modified tip relief angle with a non-zero angle, the relief face can also be ground into the form of a carrot having a slightly curved surface in the radial direction. An additional swivel axis of the tool head 78 (not shown in FIG. 1) can be used to generate a head relief angle other than zero degrees.

[0043] As a rule, a relatively flat cup can be used as a cup wheel or, alternatively, a dish wheel. Compared to a solid cylindrical wheel, only a narrow area is used in the case of a cup wheel, and the cup wheel can be aligned more easily and accurately, which is advantageous for aligning grinding tools.

[0044] FIG. 2 shows the shape of a skiving wheel S that can be used in the machine 100 shown in FIG. 1. The step cut design of the teeth 4 of the tool with the step cut rake face 5 can be clearly seen. The tool S shown in FIG. 2 has a non-zero tip rake angle Φ (FIG. 7), and the rake face is also inclined with respect to the radial direction.

[0045] FIG. 3 shows the intervening situation during regrinding the cutting wheel S3 using a grinding tool M3 in the form of a cup-shaped grinding wheel. It can be seen that the rotational axes of the cutting wheel S3 and the grinding tool M3 are pivoted towards each other once for a right-hand cutting design and once for a left-hand cutting design to coincide with the modified stepped grinding angle τ.

[0046] FIG. 4 schematically shows a variant in which a cutting wheel S4 without step grinding is reground by a rotating cylindrical grinding wheel M4. Here, it can be seen how the relative angular positions of the respective rotational axes are set to coincide with the modified tip rake angle of the cutting wheel S4. The grinding stroke movement is indicated by the arrows on both sides. However, for example, performing a compensating movement in the direction of the axis of the cutting wheel and coupling it to the grinding stroke is also conceivable. This type of cylindrical grinding tool, such as M4, in the case of step grinding, instead of the regrinding position shown in FIG. 4, can also be used at a position rotated by 90° (an intermediate position between 0° close to the skiving head and 180° away from the skiving head), possibly with an offset.

[0047] Figure 5 shows again the detailed view of the step cut cutting wheel with the step angle drawn. Figure 6 shows, for the purpose of explanation, which modifications of the profile of the workpiece tooth part are caused by the change of the step angle. Thus, reducing the step angle in the view of Figure 5 increases the profile angle on the upper left side and decreases the profile angle on the upper right side (Figure 6A), and increasing the step angle has the opposite effect (Figure 6B). The influence of the modified tool is indicated by the dashed line. Changing the tool from right-handed to left-handed or vice versa mirrors the influence.

[0048] Figure 7 shows again the tip relief angle φ for the details of the shown step cut cutting wheel. Similar to Figure 6, Figure 8 corresponds to the view of the influence of the modification by regrinding the relief face 5 to different tip relief angles. Here, reducing the tip relief angle increases the profile angles on both sides of the workpiece (Figure 8A), while increasing the tip relief angle decreases the profile angles on both sides (Figure 8B).

[0049] Therefore, by superimposing both corrections, the symmetric part of the profile deviation can be corrected by correcting the tip relief angle, and the asymmetric part of the profile deviation can be corrected by the influence of the step angle.

[0050] For example, a set of teeth of a workpiece batch has the following gear data: module 1.7, pressure angle 20°, number of teeth 90, helix angle 0 (straight), tooth width 25 mm; root circle diameter 155 mm; tip circle diameter 148 mm, and the cutting wheel used to generate this set of teeth has the following parameters: number of teeth 54; helix angle 10°, as well as step angle 10° and tip relief angle 5°, and as shown in the measurement profile of FIG. 9A, for this cutting wheel, when the profile deviation is determined to be 3.9 μm on the left side and 9.3 μm on the right side, in this specific embodiment, a compensation re-grinding of the relief surface of the cutting wheel to a tip relief angle of 3° and a step angle of 12° is performed. From the measurement profile of FIG. 9B generated using the modified (corrected) cutting wheel, it is possible to recognize the effect of the re-grinding that cancels the deviation from FIG. 9A.

[0051] As can be seen from the above, the present invention is not limited to the implementation modes specifically shown in the preceding embodiments. Rather, the individual features of the above specification and the following claims may be essential, individually and in combination, for implementing the present invention in its different embodiments.

Claims

1. A method for generating or machining, by cutting, the same set of teeth on each of a plurality of workpieces in a workpiece batch, in a gear cutting machine having a gear cutting tool (S) having a set of teeth with a rake face (5) and having a rotational axis in a rolling machining engagement, wherein if a deviation of the set of teeth from the tooth profile required for the set of teeth is detected or predicted, a countermeasure for canceling the deviation is determined, and using the countermeasure, the generation / machining of additional workpieces in the workpiece batch is continued, The countermeasure is at least partially a change in the position (φ, τ) of the rake face (5) with respect to the rotational axis of the gear cutting tool (S), and the change is brought about by grinding performed in the gear cutting machine or in a grinding machine (140) belonging to a group of machines of the gear cutting machine.

2. The method according to claim 1, wherein the gear cutting tool does not receive a coating having a wear-resistant layer between its grinding operation and the continuation of its use.

3. The method according to claim 2, wherein the rake face (5) of the gear cutting tool (S) is ground to a modified tip rake angle (φ) during the grinding operation.

4. The method according to claim 3, wherein the rake face (5) of the gear cutting tool (S) is step-ground and ground to a modified step angle (τ) during the grinding operation.

5. The machining engagement is performed using the two-tooth flank method, and the modification of the step angle (τ) cancels an asymmetric portion of the profile error with respect to the deviation on the left and right tooth flanks.

6. The machining engagement is performed using the two-tooth flank method, and the modification of the tip rake angle (φ) cancels a symmetric portion of the profile error with respect to the deviation on the left and right tooth flanks.

7. The measure also includes dynamic correction of the form of the movement of the machine axes (A1, Y1) for generating / machining the set of teeth, corrected using the detected deviation, in the case where the relative position of the rake face is partially changed, according to the method of any one of claims 1 to 6.

8. The dynamic correction is independently calculated by a controller that controls the machine axes for machining engagement, according to the method of claim 7, in response to the correction performed on the rake face.

9. The method according to claim 5 or 8, wherein the machine axes for machining engagement are used to position the gear cutting tool during its grinding operation.

10. The method according to claim 5 or 8, wherein the machining engagement is gear hobbing or gear shaping.

11. A group of machines, comprising a gear cutting machine (100) provided with a controller for generating and / or machining gear teeth on a workpiece by cutting in a rolling machining engagement, and a grinding machine (140) for grinding the rake face of the gear cutting tool used in the gear cutting machine, the controller of the grinding machine being connected to or included in the controller of the gear cutting machine, the controller being designed for control according to the method of any one of the preceding claims in at least one operating mode of the group of machines.

12. The group of machines according to claim 11, wherein the gear cutting machine (100) and the grinding machine (140) form a combination of machines (200).

13. The group of machines according to claim 11 or 12, further comprising a tooth part tester for measuring the profile and profile error of the gear teeth.

14. A control program that, when executed on a controller of a gear cutting machine of a mechanical assembly or a group of machines according to any one of claims 11 to 13, controls the controller to perform the method according to any one of claims 1 to 10.

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