Method for polishing and grinding gears with a polishing and grinding tool in a gear grinding machine

Abstract

The invention relates to a method for polishing and grinding gears with a polishing and grinding tool in a gear grinding machine.To ensure that the surface quality (roughness) of the tooth flanks is not only maintained within an optimal range during a polishing and grinding process, but also to achieve the best possible geometry of the machined gear, the procedure comprises the following steps: a) Measuring the tooth flanks of a tooth gap on a pre-ground reference gear across the tooth height and tooth width at a number of measuring points; polishing and grinding the gear with an initial radial infeed; remeasuring the flank surface; comparing the measured position of the tooth flanks with the original position; if the comparison shows that not all measuring points have yet been changed: saving the measured positions of the flanks where a change has already occurred, as well as the required radial infeed, and repeating the polishing and grinding with an incrementally increased infeed; b) Determining a correction value or...a correction function for the subsequent polishing grinding from the determined radial infeeds required for a change at all measured points of the flanks; c) polishing grinding of gears based on the determined correction value or the determined correction function.

Description

[0001] The invention relates to a method for polishing and grinding gears with a polishing and grinding tool in a gear grinding machine.

[0002] In the hard finishing of a gear's teeth, polishing is sometimes used as the final step. This process removes relatively little material from the surface of the tooth flanks, but it also defines the final shape and surface finish (roughness) of the tooth flanks.

[0003] The polishing tool used typically contains abrasive grains held to a tool body by a relatively soft bond (for example, polyurethane). While a polishing effect can be achieved with appropriate tool positioning relative to the workpiece, unlike the preceding grinding process, it is no longer possible to easily create a desired geometry on the tooth flanks.

[0004] Nevertheless, it would be advantageous to carry out the final polishing and grinding process in such a way that the final surface topography of the tooth flanks, with regard to their geometric position and surface roughness, is optimally achieved.

[0005] From EP 4 537 966 A1, a gear grinding process is known in which both the roughing and finishing of a gear are carried out with respective quality control loops. The machining of the gear after finishing by means of a polishing grinding process is not addressed in the solution described therein. Grinding and polishing processes for gears are also described in DE 10 2019 104 812 A1 and in DE 10 2020 006 418 A1.

[0006] The invention is based on the objective of further developing a method of the type mentioned above in such a way that, even during a polishing and grinding process, not only is the surface quality (roughness) of the tooth flanks kept in an optimal range, but also the best possible geometry of the machined gear can be achieved.

[0007] The solution to this problem by the invention is characterized in that the method for polishing and grinding the gear comprises the following steps: a) Perform the following steps on a reference gear or test gear: a1) Measuring at least one tooth gap of the pre-ground, namely finished but not yet polished gear, wherein on the two opposing flanks of the tooth gap the position of the surface of the flanks is measured at a number of points on the flanks (measuring points) both over the tooth height (i.e. over the diameter of the gear) and over the tooth width (i.e. along the width extent of the toothing); a2) Polishing and grinding of the gear with the polishing and grinding tool, wherein the polishing and grinding tool is brought into contact with the gear with a first initial radial approach; a3) Measuring the surface of the flanks to determine the position of the surface at the number of points on the flanks; a4) Comparison of the measured position of the surface at the number of points on the flanks according to step a3) with the measured position of the surface at the number of points on the flanks according to step a1); a5') If the comparison according to step a4) shows that the position of the surface at the number of points on the flanks according to step a3) with the measured position of the surface at the number of points on the flanks according to step a1) has resulted in a change at all measured points on the flanks: continue with step b); a5'') If the comparison according to step a4) shows that the position of the surface at the number of points on the flanks according to step a3) with the measured position of the surface at the number of points on the flanks according to step a1) has not yet resulted in a change at least at one of the measured points on the flanks: Store the measured points on the flanks where a change has already occurred and the radial feed required for this, Repeat steps a2), a3) and a4), wherein with each repetition the polishing tool is moved to the gear with a radial approach increased by one increment, continuing with step b) if, after a repetition, a change has occurred at all measured points of the flanks; b) Determination of at least one correction value and / or at least one correction function for the subsequent polishing grinding from the determined radial infeeds required for a change at all measured points of the flanks; c) Polishing and grinding of gears based on the determined correction value and / or the determined correction function.

[0008] The measurement according to step a1) above is preferably carried out on exactly one reference tooth gap.

[0009] Preferably, between 3 and 20 measuring points are arranged equidistantly along the tooth height, and between 3 and 10 measuring points along the tooth width. A lower limit of 5 measuring points is particularly preferred. The selected number of measuring points is generally a compromise between the information obtained and the time required to perform the measurement. A lower resolution is preferably used along the tooth width than along the tooth height (profile) (i.e., a smaller number of measuring points).

[0010] According to a first preferred embodiment of the method, the determination of the aforementioned correction value according to step b) above relates to the symmetry between the two tooth flanks of the tooth gap of the gear to be polished. In this case, it can be specifically provided that, from the stored radial infeed values ​​at the measured locations of the flanks according to step a5'') above, where a change first occurred, an average value is calculated for both the right and left flanks. From the difference between the average values ​​of the left and right flanks, a compensating rotation angle is determined by which the gear is rotated by a machine axis during machining in order to polish the opposing flanks of the tooth gap symmetrically. In this way, the polishing process is carried out in such a way that optimally symmetrical flanks result.

[0011] A second preferred embodiment provides that the determination of the correction function according to step b) above relates to the flank line of the gear teeth to be polished. In this case, it can be specifically provided that, from the stored radial infeed values ​​at the measured locations of the flanks according to step a5'') above, where a change first occurred, an average flank line profile is determined across the width of the gear teeth, the profile of which is determined in this way is taken into account as a correction during polishing in order to obtain a desired flank line profile.

[0012] A third preferred embodiment provides that the determination of the correction function according to step b) above relates to the flank profile of the gear teeth to be polished. In this case, it can be specifically provided that, from the stored radial infeed values ​​at the measured locations of the flanks according to step a5'') above, where a change first occurred, an average flank profile over the height of the gear teeth is determined, wherein the flank profile thus determined is taken into account as a correction when dressing the polishing tool, in order to obtain a desired flank profile during polishing.

[0013] The three approaches mentioned can also be used in any combination.

[0014] The measurement according to step a1) above and according to step a3) above is preferably carried out in the workpiece clamping in the gear grinding machine.

[0015] The measurement according to step a1) above and according to step a3) above is preferably carried out using a tactile measuring element (i.e. in particular with a measuring probe).

[0016] The polishing grinding tool is preferably a grinding worm. In this case, the grinding worm preferably has abrasive grains held in place by an elastic bond, in particular by a plastic bond, most preferably by a polyurethane bond.

[0017] The above-mentioned increment for the radial feed is preferably between 20 µm and 50 µm, particularly preferably 30 µm.

[0018] The proposed procedure allows the polishing tool to gradually approach the flank surface radially, based on the aforementioned increment, until the described measurement and comparison with the original surface position of the tooth flanks confirms that material has been removed across the entire tooth flank (step a above). The subsequent determination of a correction value or function (step b above) is then carried out using the preferably single tooth gap under consideration (i.e., measured) in such a way that the symmetry between the two tooth flanks and / or the flank line and / or the flank profile are optimally achieved during the subsequent polishing process (step c above).

[0019] This can improve the quality of the gearing.

[0020] Advantageously, a targeted, surface-based modification of the gear grinding topology during polishing can be achieved based on the determined penetration depth distribution according to step a) above. This is done with sufficient precision to achieve improved gear quality.

[0021] The process can run automatically in the machine; it is operator-independent.

[0022] The method thus enables a targeted determination of the distribution of the polishing pressure over the surface of the tooth flanks (which is determined iteratively by a sequence of individual steps according to step a above) and its conversion into correction values ​​or correction functions, with which the polishing grinding can then take place.

[0023] The drawing shows exemplary embodiments of the invention. Fig. Figure 1 shows an Abbott curve in a general representation, Fig. Figure 2a shows a specific Abbott curve of a tooth flank that was initially only ground (underpolished profile), where a feed of the grinding / polishing tool of 5 µm was chosen. Fig. Figure 2b shows the Abbott curve of a subsequently polished tooth flank (minimally overpolished), where a feed of the grinding polishing tool of 30 µm was chosen. Fig. Figure 2c shows the Abbott curve of an even more highly polished tooth flank (overpolished), where a feed of the grinding polishing tool of 90 µm was chosen. Fig. Figure 3 shows measured curves for various resulting roughnesses of the tooth flank over the radial feed (z) of the grinding polishing tool. Fig. Figure 4a shows recorded measurements during the measurement of the left flank of a reference tooth gap after performing a polishing grinding process with a predetermined radial feed of the grinding polishing tool, showing the position of the surface of the tooth flank over the tooth height (diameter d of the gear) and the tooth width (b). Fig. 4b shows in the representation according to Fig. 4a the corresponding recorded measurements for the right flank of the reference tooth gap, Fig. Figure 5 schematically shows how a radial approach of the tool to the gear results in a target penetration (ZD) which is the goal for polishing grinding. Fig. Figure 6 schematically shows the target penetration ZD (in µm) across the tooth width (b) for different tooth heights (diameter values ​​from 100 to 106 mm) and Fig. Figure 7 schematically shows the target penetration ZD (in µm) across the tooth height (d) at different points on the tooth width.

[0024] In Fig. Figure 1 shows a general Abbott curve that can be used to describe the surface texture of a tooth flank. The curve describes the distribution of the flank surface height profile and is calculated by integrating (from 0% to 100%) the surface profile. The curve is suitable for describing the flank surface and is related to the surface roughness parameters Rpk, Rk, and Rvk.

[0025] As from Fig. As can be seen in Figure 1, for a percentage of the surface roughness (from 0% to approximately 8% of Mr1), it lies above a mean value (Rk) and exhibits a maximum value exceeding Rpk. For another percentage of the surface roughness (from approximately 88% to 100% of Mr2), it lies below the mean value (Rk) and exhibits a minimum value of Rvk.

[0026] The ideal tooth flank surface is characterized by minimal deformation due to wear of the roughness peaks. In this case, a high bearing area of ​​the surface is available; simultaneously, there is good retention capacity for the lubricant used in gear operation. This lubricant is retained in the roughness valleys. The resulting gear teeth are advantageously able to maintain constant engagement conditions and center distances during operation, transmit high loads, and provide sufficient lubricant for favorable friction conditions. Likewise, a smoother roughness profile leads to lower local power loss due to sliding friction losses in operating conditions with solid or mixed friction.

[0027] The desired surface finish for gear teeth is often a technical surface that is intermediate between a ground and a fully polished surface. The peaks or roughness profile are already transformed into a polished surface through the polishing process. However, the roughness valleys from the grinding process are retained.

[0028] In Fig. Figure 2 illustrates this.

[0029] The first scene depicts Fig. 2a a tooth flank that has only been ground or underpolished, where only the tips have been minimally smoothed.

[0030] In Fig. Figure 2b shows the case where the peaks are smoothed, resulting in a high bearing area (flatter Abbott curve). However, residual valleys remain in the profile, stemming from the previous grinding process. Normally, such an Abbott curve shape is the desired outcome.

[0031] In Fig. Figure 2c shows a fully polished surface, which, considering the surface finish of a gear tooth flank, can be described as overpolished. Only minimal residual valleys remain, thus reducing the oil retention capacity. The Abbott curve is even flatter here than in Figure 2c. Fig. 2b.

[0032] The retention capacity of lubricant is ultimately determined by the Rvk value of the Abbott curve (see...). Fig. 1) relevant.

[0033] The resulting transition from a merely ground surface of a tooth flank to a polished surface is in Fig. Figure 3 outlines the course of roughness parameters (especially Ra, Rpk and Rvk) according to the Abbott curve, see Figure 3. Fig. 1), which results from a relative radial approach Z of the polishing tool to the gear to be polished.

[0034] It can be seen that a certain feed rate (Z) is initially required before any noticeable effect on the surface roughness can be observed. For example, reference is made to the Ra value, which has no effect at all with feed rates below 10 µm. This is ultimately due to the elasticity of the polishing tool. Its abrasive particles are usually fixed to the tool body in an elastic bond (e.g., polyurethane), so a certain minimum feed rate is required before any effect is detectable.

[0035] The proposed procedure follows this approach: First, a reference gear or test gear is mounted on the workpiece spindle of a (polishing) grinding machine. The reference gear is already ground; only the grinding and polishing process remains. The reference gear can be the first workpiece of a batch to be produced, which may subsequently be polished to a final finish; however, it can also be a gear that becomes scrap after the described machining and measurement.

[0036] A polishing grinding tool is clamped on the tool spindle, which may in particular be a polishing grinding worm whose bond is made of plastic (especially polyurethane) and which (compared to a grinding worm for finishing the gear teeth) is correspondingly flexible or elastic.

[0037] The following procedure is now performed with the reference gear or test gear: A (preferably) single reference tooth gap is defined on the reference gear, which forms the basis for further investigation. This tooth gap is measured using a tactile measuring element (probe). A predefined grid of measuring points is approached both along the tooth height (i.e., in the radial direction of the gear) and along the tooth width (i.e., in the axial direction of the gear), and the position of the surface of the two opposing tooth flanks of the reference tooth gap is recorded and stored (see step a1 above). For example, 10 measuring points can be provided along the tooth height and 5 measuring points along the tooth width, resulting in 50 measuring points per tooth flank in this case.

[0038] The gear now undergoes an initial polishing and grinding process using the polishing tool. The tool is initially positioned with a small radial infeed towards the gear (see step a2 above).

[0039] The surface of the tooth flanks is then measured again; the position of the surface (in the example case at the 10 x 5 = 50 measuring points) is recorded and saved again (see step a3 above).

[0040] The measuring points are now compared as they appear before and after the first polishing process (see step a4 above). The initial radial infeed is chosen so that no changes are expected at any of the measuring points as a result of the first polishing process. For example, the initial radial infeed can be in the range of 10 µm, which is the depth at which the tool plunges relative to the workpiece, starting from the target geometry of the tooth flanks.

[0041] In this respect, the aforementioned comparison (according to step a4) will regularly show that the position of the surface of the opposing tooth flanks at the measuring points does not completely correspond to the measured position according to step a1 at all measuring points; changes will regularly only have occurred at some measuring points.

[0042] For all measuring points where a change from the initial state has already been observed, the radial infeed that led to the surface change and the specific measuring point are recorded. This radial infeed, due to the geometric conditions at the flank surface (i.e., the shape of the involute), results in a corresponding infeed normal to the flank surface. The desired immersion depth (θ) for polishing is then added to this normal infeed to achieve the desired target penetration (see...). Fig. 5).

[0043] Since changes have not yet occurred at all measuring points, the polishing process is now continued (according to step a5) by advancing the polishing tool by an incremental amount of the radial feed. This incremental amount can be, for example, between 20 µm and 40 µm, particularly 30 µm. After the polishing process is repeated, the measurement is checked to see if changes have now occurred at all measuring points compared to the initial state.

[0044] Measuring points for which a change from the initial state is now detected are again recorded, along with the radial approach last used or the resulting penetration (see below). Fig. 5) saved.

[0045] The procedure is repeated with incrementally increasing delivery until the measurement shows that the measured values ​​at all measuring points have changed compared to the initial state.

[0046] In the Fig. 4a and Fig. 4b is the measured progression or surface position of the tooth flank for one of these intermediate states (between the first polishing and the last polishing). Fig. 4a for the left tooth flank and in Fig. 4b for the right tooth flank of the reference tooth gap) is sketched. The (iso)lines shown (“0.04”, “0.045”, “0.05” etc. in mm) indicate the reduction over the surface of the tooth flank (see AB in Fig. 5).

[0047] In both Fig. 4a and Fig. Area 4b is marked "A" where no change has yet been observed compared to the first measurement. Accordingly, the polishing process continues with a further increased increment until, after a final repetition, a change has been observed at all measuring points on the tooth flanks.

[0048] If this is the case, the polishing process is stopped and the data obtained are used as the basis for determining a correction value or a correction function (see step b above).

[0049] According to a first preferred embodiment, the determined data is intended to form the basis for the subsequent polishing and grinding of gears in such a way that an improved symmetry of the two opposing tooth flanks is achieved, with reference to the center of the tooth gap.

[0050] For this purpose, differences are calculated at the measuring points (in this example, at the 10 x 5 = 50 measuring points) for both the left and right tooth flanks of the reference tooth gap, which was machined as described above. These differences result from the respective feed rate until the geometry changes, minus the feed rate at the start of the process. An average value (for example, the arithmetic mean: sum of all differences for all measuring points divided by the number of measuring points) can be determined for these differences, so that a value is available for both the left and right tooth flanks of the reference tooth gap. From this, a rotation angle of the workpiece relative to the tool (i.e., a rotation around the C-axis) can be calculated – for example, with reference to the pitch circle of the gear teeth – so that the tool is positioned symmetrically relative to the workpiece or to the tooth gaps to be ground.

[0051] In the aforementioned embodiment, the correction value (according to step b above) therefore consists of a specific rotation angle around the workpiece axis, which is taken into account during the subsequent polishing grinding (according to step c above) in order to machine the gears with improved symmetry of the tooth gaps with respect to their central plane.

[0052] In Fig. Figure 5 illustrates how a radial infeed r of the polishing tool 1 to the workpiece 2 (gear) results, due to the geometric relationships (i.e., specifically due to the angle that the surface normal at a considered point on the flank surface 3 forms with the radial direction r), in a feed and thus a penetration DU perpendicular to the surface of the tooth flank 3 (see upper image in Figure 5). Fig. 5) Accordingly, the image above shows in Fig. 5 also, how a radial feed r leads to a penetration DU, which is to be understood as perpendicular to the flank surface 3; between radial feed r and penetration DU there is thus a correlation which results from the geometric conditions of the gearing.

[0053] In the lower image in Fig. Figure 5 is represented in the form of a coordinate system, showing which penetration DU results in which material removal AB on the tooth flank 3.

[0054] With reference to the explanations regarding Fig. It should be recalled that a certain amount of infeed (perpendicular to the tooth flank) is required to achieve any effect at all. As explained above (see step a above), a certain penetration DU must first be achieved for the individual points on the surface of the tooth flanks before any change in the surface can be observed (see lower image in Fig. 5: Initially, with increasing penetration DU, no material removal AB occurs, which is why the curve runs along the abscissa. Only when sufficient penetration DU is achieved does the surface change begin at the relevant point on the tooth flank (see the rising straight line from the beginning of Θ). At this point, the immersion depth Θ (e.g., 5 µm, 10 µm, 15 µm, or 20 µm) is then added (see the lower image in [reference]). Fig. 5) with which the polishing grinding process itself is to be carried out in order to achieve a desired target penetration ZD. According to the described procedure, this is done for the entire surface of the tooth flanks, i.e. according to the measuring points provided there in the radial direction as well as in the width direction of the gear teeth.

[0055] The target penetration ZD is therefore obtained when, for each point after performing step a) above, the desired defined immersion depth Θ is added to achieve the desired polishing effect.

[0056] According to a further embodiment of the invention, the data set determined above for the individual measuring points (concerning the aforementioned difference) can also be used to improve the tooth line in the direction of the axis of rotation of the gear, i.e. in the width direction of the toothing, during polishing grinding (according to step c above).

[0057] Such a procedure is in Fig. 6 illustrated.

[0058] This shows the extent of the target penetration ZD (in µm) across the tooth width b for various diameters d (i.e., across the tooth height). The target penetration ZD is defined as follows: Fig. 5. Referenced.

[0059] As in Fig. As can be seen in Figure 6, a similar pattern emerges across the tooth width b for the different diameters d. For all recorded patterns, a mean value (for example, an arithmetic mean) can be determined, so that from the data in Fig. From the seven curves shown in 6, a single representative curve is formed which applies to the target penetration ZD over the width b of the gearing.

[0060] This curve profile can then be considered as a correction function during the polishing and grinding of gears (according to step c above), i.e., a line correction of the gear teeth is taken into account in the machine control by a variable radial feed (X-axis) along the axis direction of the gear teeth (Z-axis). The resulting Fig. The 6th obtained representative curve is thus “counteracted” during polishing and machining along the workpiece axis in order to achieve an improved line as a result.

[0061] This line correction can also be achieved, in particular, via a Z-dependent feed (of the X-axis) in combination with a Z-dependent rotation around the workpiece axis (C-axis) during the subsequent polishing and grinding process (according to step c above). Alternatively, the correction can be applied by selectively shifting the tool along its axis of rotation (shift axis: Y-axis) during the polishing and grinding process.

[0062] Another possible design of the procedure is to determine a correction function that is based on the tooth profile (i.e., the profile across the height of the teeth). This is in Fig. 7 illustrated.

[0063] Here, the target penetration ZD (in µm) is shown as a function of the gear diameter d (i.e., the tooth height) for all measured points along the tooth width (where the curves are all very similar and therefore close together). From this data, a mean value (e.g., the arithmetic mean) can be calculated to define a function used to modify the gear teeth during the subsequent polishing process (according to step c above).

[0064] However, in this case, the correction function is taken into account during the subsequent polishing process (according to step c above) in such a way that the Fig. The function gained in point 7 is taken into account when dressing the grinding / polishing tool (i.e., in particular the grinding screw). The dressing process is therefore carried out in such a way that the function derived from Fig. 7. The resulting function is "held back" or superimposed when dressing the polishing part of the tool.

[0065] Accordingly, the gear profile can be specifically influenced.

[0066] It should be mentioned here that the implementation of the determined correction functions can also be achieved using conventional methods, for example, by defining a spline function that describes the desired corrections and is taken into account when controlling the axes. Similarly, a polynomial can be defined for the correction function, which is then considered by the machine control system.

[0067] Therefore, the following can be stated: When the described procedure is used to determine the local polishing conditions, a compensation topology (correction value or correction function) is available for the subsequent polishing grinding (according to step c above).

[0068] The procedural approach allows local polishing properties on the surface of the tooth flanks to be taken into account, thus defining a compensation topology that compensates for the locally different penetration.

[0069] The described method makes it possible to transfer the determined measured values ​​into the kinematics of the machine during polishing grinding via a correction value or correction function, or to take them into account when dressing the grinding screw.

[0070] This makes it advantageously simple and cost-effective to achieve improved polishing results. The surface finish can be improved to a higher quality. The process can be automated, making it more economical.

[0071] The above describes three specific solutions that improve the symmetry of the gap between teeth, the alignment of the teeth, and the overall tooth profile. These approaches can be implemented individually or in any combination.

[0072] To improve symmetry, the flanks are compensated by determining a compensating rotation angle for the workpiece, as described above. The average target penetration on both measured flanks of the reference tooth gap is thus compensated for by a C-axis correction.

[0073] Similarly, a compensation function can be used to influence the surface geometry of the tooth flanks in the linear direction (i.e., in the direction of the gear's axis of rotation). Here, several axes of the machine are interpolated accordingly by the control system to implement the determined compensation function during polishing and grinding.

[0074] However, a compensation function, which concerns the profile (over the tooth height), can be taken into account when dressing the grinding tool.

Claims

A method for polishing gears with a polishing tool in a gear grinding machine, comprising the steps of: a) performing the following steps on a reference gear or test gear: a1) measuring at least one tooth gap of the pre-ground, i.e., finished but not yet polished, gear, wherein the position of a surface on the flanks is measured at a number of points on the flanks (measuring points) on both opposing flanks of the tooth gap over a tooth height and a tooth width; a2) polishing the gear with the polishing tool, wherein the polishing tool is fed to the gear with a first initial radial feed; a3) measuring the surface of the flanks to determine the position of the surface at a number of points on the flanks;a4) Comparison of the measured position of the surface at the number of flank locations according to step a3) with the measured position of the surface at the number of flank locations according to step a1); a5') If the comparison according to step a4) shows that the position of the surface at the number of flank locations according to step a3) has changed at all measured flank locations compared to the measured position of the surface at the number of flank locations according to step a1): proceed with step b);a5'') If the comparison according to step a4) shows that the position of the surface at the number of points on the flanks according to step a3) with the measured position of the surface at the number of points on the flanks according to step a1) has not yet resulted in a change at least at one of the measured points on the flanks: Store the measured points on the flanks where a change has already occurred and the radial feed required for this, Repeat steps a2), a3) and a4), wherein in each repetition the polishing tool is fed to the gear with a radial feed increased by one increment, wherein the process continues with step b) if, after a repetition, a change has occurred at all measured points on the flanks;b) Determination of at least one correction value and / or at least one correction function for subsequent polishing grinding from the determined radial infeeds required for a change at all measured points of the flanks; c) Polishing grinding of gears based on the determined correction value and / or the determined correction function. Method according to claim 1, characterized in that the measurement according to step a1) according to claim 1 is carried out on exactly one reference tooth gap. Method according to claim 1 or 2, characterized in that measuring points are arranged equidistantly between 3 and 20 above the tooth height. Method according to one of claims 1 to 3, characterized in that measuring points are arranged equidistantly over the tooth width between 3 and 10. Method according to one of claims 1 to 4, characterized in that the determination of a correction value according to step b) of claim 1 relates to the symmetry between the two tooth flanks of the tooth gap of the gearing to be polished. Method according to claim 5, characterized in that an average value is formed for both the right flank and the left flank from the stored radial infeed values ​​at the measured locations of the flanks according to step a5'') of claim 1, where a change has first occurred, wherein a compensating rotation angle is determined from the difference of the average values ​​of the left and right flanks, by which the gear is rotated by a machine axis during machining in order to polish the opposing flanks of the tooth gap symmetrically. Method according to one of claims 1 to 4, characterized in that the determination of a correction function according to step b) of claim 1 relates to the flank line of the gear teeth to be polished. Method according to claim 7, characterized in that from the stored radial infeeds at the measured locations of the flanks according to step a5'') of claim 1, where a change has first occurred, a mean course of the flank line over the width of the gearing is determined, wherein the course of the flank line thus determined is taken into account as a correction during polishing grinding in order to obtain a desired course of the flank line. Method according to one of claims 1 to 4, characterized in that the determination of a correction function according to step b) of claim 1 relates to the flank profile of the gear teeth to be polished. Method according to claim 9, characterized in that from the stored radial infeeds at the measured locations of the flanks according to step a5'') of claim 1, where a change has first occurred, a mean course of the flank profile over the height of the toothing is determined, wherein the course of the flank profile thus determined is taken into account as a correction when dressing the polishing grinding tool in order to obtain a desired course of the flank profile during polishing grinding. Method according to one of claims 1 to 10, characterized in that the measurement according to step a1) and according to step a3) of claim 1 is carried out in a workpiece clamping in the gear grinding machine. Method according to one of claims 1 to 11, characterized in that the measurement according to step a1) and according to step a3) of claim 1 is carried out by means of a tactile measuring element. Method according to one of claims 1 to 12, characterized in that the polishing grinding tool is a grinding screw. Method according to claim 13, characterized in that the grinding screw has abrasive grains which are held by an elastic bond. Method according to one of claims 1 to 14, characterized in that the increment for the radial feed is between 10 µm and 50 µm.

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