Modification tool for modifying a grinding steel for generating a workpiece

Abstract

The invention relates to a dressing tool for dressing a grinding worm for generating a workpiece with pre-formed teeth, which dressing tool is designed for rotation about a dressing rotation axis (A) and has a dressing side surface which forms a circular ring in a projection plane perpendicular to the dressing rotation axis of the dressing tool, wherein the circular ring defines a radial direction having radial coordinates (r) and a circumferential direction having angular coordinates (phi). The trimming side surface is provided with a trimming side modification which is produced in a targeted manner, and the trimming side modification can be described as a two-dimensional Fourier series related to a radial coordinate (r) and an angular coordinate (phi) in a manner projected onto a circular ring. The Fourier series has at least one non-zero Fourier coefficient for a non-zero circumferential frequency component with respect to the angular coordinates.

Description

Technical Field

[0001] The present invention relates to a dressing tool for dressing a grinding worm for generating workpieces with pre-formed teeth, a method for producing such a dressing tool, and an adjustment device designed to carry out such a method for producing such a dressing tool. The present invention also relates to a method for dressing a grinding worm for generating workpieces with pre-formed teeth using such a dressing tool, and a method for producing a modified surface structure on the tooth flanks of a workpiece with pre-formed teeth using a grinding worm dressed using such a dressing tool. Background Art

[0002] Particularly in the context of electric vehicles, the topic of NVH (Noise-Vibration-Harshness) has become important, particularly in the area of ​​vehicle transmissions, due to the absence of the primary background noise of the internal combustion engine. Requirements for noise excitation characteristics are often set in the form of predefined limit values ​​in the noise spectrum. Typically, workpieces are randomly checked on end-of-line (EOL) test benches to determine whether these requirements are met. If the measured amplitude of an isolated noise frequency exceeds the predefined limit value, the corresponding workpiece is rejected.

[0003] The typical noise spectrum of a rotating gear is at the frequency corresponding to the tooth meshing frequency (f ZE = gear rotational frequency x number of teeth) and the associated higher-order harmonics at the corresponding tooth meshing order (ZEO) have their dominant amplitude at the noise frequencies. These dominant noise frequencies are typically caused by rotational path deviations, which arise from varying meshing stiffness across the meshing segment. The profile of meshing stiffness as a function of position along the meshing segment repeats periodically with the meshing pitch and causes the aforementioned dominant noise frequencies. Another cause can be "spreading holes" created during manufacturing, i.e., material that has retreated relative to the desired contour.

[0004] In general, all rotational path deviations of the toothing under load can lead to noise excitations that can be perceived as disturbing noise. For example, if the correction tool has a certain waviness in the profile height, this waviness is transferred to the worm and subsequently causes deviations in the profile shape on the workpiece.

[0005] Constant vibrations in the vicinity of machine tools for machining workpieces with prefabricated teeth can also cause tooth flank waviness on the tooth flanks, which can be detected using measurement technology and lead to a disturbing noise characteristic of the toothing.

[0006] Indentations extending across the width of the toothing can also cause noise excitation. In general, any periodic surface structure, especially in a direction perpendicular to the meshing line of the mating spur gear, can cause the excitation of noise frequencies that primarily appear in the noise spectrum of the toothing.

[0007] There are various options for improving the noise-inducing properties of toothing. Rotational path deviations caused by deformation of the toothing under load can be effectively reduced through targeted shaping of the tooth flanks. Generated holes can be almost completely eliminated through optimized process control.

[0008] DE 10 2012 015 846 A1 discloses a generating grinding method, in which a workpiece is machined with the aid of a grinding worm, wherein, by means of the targeted generation of an unbalance-induced oscillating motion of the grinding worm and / or an eccentricity of the grinding worm, a modification, in particular a profile modification or profile waviness and / or a defined periodic tooth flank waviness, is produced on the effective surface of the workpiece machined thereby, in order to modify or prevent undesirable tooth flank waviness.

[0009] The tooth flank waviness on the workpiece caused by the imbalance or eccentricity of the grinding worm always has an order of 1 with respect to the worm rotation frequency, ie it is not possible to generate tooth flank waviness of a higher order with respect to the worm rotation frequency in the described manner.

[0010] DE 10 2013 003 795 A1 discloses a method for hard fine machining of tooth flanks on a gear machining machine using correction and / or reshaping. Gear pairs meshing with each other in a transmission or inspection device are machined while taking into account the corresponding mating flanks, and the tooth flanks of the workpieces involved are provided with a periodic waviness correction or reshaping. According to the invention, the rotational error profile is determined in the gear measuring device and / or the transmission by measuring the rotational run error of the gear pairs. The measurement results serve as input variables to define the amplitude, frequency, and phase of the periodic flank waviness correction on the tooth flanks of the gear pairs produced in the gear machining machine.

[0011] Periodically repeating surface structures tend to induce excitation within a relatively narrow noise frequency band. Surface structures that are minimally uniform, in turn, result in a very broad noise spectrum that approaches "white" noise, that is, a noise spectrum with equal amplitudes for all noise frequencies. This noise spectrum, which tends to reduce the dominance of individual noise frequencies, is perceived as less disturbing psychoacoustically and is therefore advantageous. Furthermore, with excitations having a broad noise spectrum, the total excitation energy is distributed over a large frequency range, so that the noise amplitude of each individual frequency component tends to be lower compared to excitations within a narrow frequency band.

[0012] If a workpiece is machined using a generating grinding method with a grinding worm, a periodically recurring surface structure can form on the tooth flanks. This surface structure, for example, results from the dressing of the grinding worm used to machine the tooth flanks. The dressing disks used in dressing can have, due to technical reasons, varying grain sizes and shapes, as well as different grain distributions, over their circumference. This results in a dressing pattern on the surface of the dressing disk. Since the dressing disk typically performs multiple revolutions during one revolution of the grinding worm, this dressing pattern is periodically mirrored on the grinding worm during dressing in the direction of the worm thread. During subsequent grinding of the workpiece, periodic fluctuations can then be generated on the tooth flanks in the form of indentations on the tooth flank surface, extending across the tooth width.

[0013] DE 199 05 136 A1 discloses a method in which the rotation angle of a dressing disk is coupled to the rotation angle of a grinding worm in an adjustable, fixed, programmable, or stored, randomly changing ratio, wherein the grinding worm is moved along its axis relative to the workpiece during grinding (displacement feed) in such a way that exactly one point of the flank of the grinding worm thread corresponds to each point of the tooth flank of the toothing of the workpiece.

[0014] By selectively selecting the displacement feed, these indentations can be destroyed. Thus, although the periodicity of the tooth flank surface structure is destroyed, which in principle results in a more pleasant noise profile, the structure transferred to the tooth flank is strongly dependent on the manufacturing-induced, random dressing pattern on the surface of the dressing disc and can therefore only be influenced during workpiece grinding via the displacement feed. Summary of the Invention

[0015] In a first aspect, the object of the present invention is to provide a correction tool with the help of which a grinding worm for developing and machining a workpiece with prefabricated teeth can be trimmed so that the grinding worm specifically produces a modified surface structure on the tooth side of the workpiece with prefabricated teeth, wherein the modified surface structure is suitable for influencing the noise characteristics of the workpiece.

[0016] This object is achieved by a method according to claim 1. Further embodiments are described in the dependent claims.

[0017] Therefore, a dressing tool for dressing a grinding worm for generating a workpiece with prefabricated teeth is proposed.

[0018] wherein the dressing tool is designed to rotate about a dressing rotation axis and has a dressing side surface which forms a circular ring in a projection plane perpendicular to the dressing rotation axis, wherein the circular ring defines a radial direction having a radial coordinate and a circumferential direction having an angular coordinate,

[0019] The finishing side surface is provided with a purposefully generated finishing side profile, wherein the finishing side profile can be described as a two-dimensional Fourier series depending on the radial and angular coordinates when projected onto a circular ring.

[0020] The Fourier series has at least one Fourier coefficient that is not equal to zero for a circumferential frequency component that is not equal to zero with respect to the angular coordinate. Figuratively speaking, this means that the trimming side modified portion has waviness in the circumferential direction.

[0021] The circumferential waviness of the correction tool can be transferred to the grinding worm side of the worm thread during dressing by appropriately presetting the speed ratio or the rotational angle coupling between the correction tool and the grinding worm to be dressed, thereby forming a worm modification with thread waviness on the grinding worm side. This thread waviness can, in turn, be used to produce targeted tooth flank waviness on the tooth flanks of workpieces with prefabricated teeth machined using the grinding worm. The correction tool proposed herein thus offers a particularly simple and elegant way to dress a grinding worm so that targeted tooth flank waviness can be produced on a workpiece using the grinding worm, while offering a high degree of flexibility in terms of the wavelength and phase of the tooth flank waviness.

[0022] In contrast to the purely radial waviness of the dressing tool, which is transmitted independently of the speed ratio between the dressing tool and the grinding worm to be dressed, the waviness can be transferred in the desired manner to the grinding worm to be dressed in the circumferential direction by prescribing the speed ratio or the rotational angle coupling between the dressing tool and the grinding worm to be dressed accordingly. Thus, the circumferential waviness on the dressing tool surface offers an additional degree of freedom in the targeted transmission of the dressing-side profile.

[0023] In order to achieve a continuous transition after one revolution of the dressing tool, in particular when dressing the grinding worm, the dressing side profile preferably has a 2π periodicity with respect to the angular coordinate, ie the dressing side profile has an integer number of wave periods with respect to the angular coordinate.

[0024] The term “wavefront” is understood hereinafter to mean a line of constant phase, or in other words a line along which no amplitude modulation occurs.

[0025] In one embodiment, the Fourier series does not have any Fourier coefficients that are not equal to zero for radial frequency components that are not equal to zero in the radial direction, so that the purposefully generated trimming side modification is wavy with respect to the circumferential direction and has a wavefront in the form of a line of constant phase that is radially oriented when projected onto a circular ring. In other words, in this embodiment, the trimming side modification has a waviness that occurs only in the circumferential direction.

[0026] In another embodiment, a two-dimensional Fourier series has at least one non-zero Fourier coefficient for radial and circumferential frequency components, such that the trimming side modification, when projected onto a circular ring, forms a checkerboard-like structure with crests and troughs staggered in a checkerboard pattern. Adjacent troughs and crests can be staggered such that they each form radial waviness along a radial path extending parallel to the radial direction. If the radial waviness of adjacent radial paths is offset by exactly 180°, a circumferential waviness is generated along the circumferential path extending parallel to the circumferential direction, wherein the circumferential paths are spaced apart in the radial direction by half the radial wavelength of the radial waviness. This checkerboard-like structure can be mathematically described as the additive superposition of two sub-waves, wherein the sub-waves have an obliquely extending wavefront when projected onto the expanded circular ring, i.e., a wavefront inclined at an inclination angle α not equal to 0°, ±90° or ±180° relative to the expanded circumferential direction, wherein the obliquely extending wavefront of the first sub-wave has a positive slope (α>0°) and the obliquely extending wavefront of the second sub-wave has a negative slope (α<0°), and wherein the first sub-wave has the same order in the circumferential direction (i.e., the same number of wave periods) and the same order in the radial direction as the second sub-wave.

[0027] In a preferred embodiment, the checkerboard structure is oriented on the ring so that troughs and crests adjacent to each other in the circumferential direction are arranged along the spiral branch that spirally stretches on the ring, wherein the number of wave periods along the spiral branch, within the angular coordinate range of 2π (i.e., counting on one revolution of the correction tool) is referred to as the order in the spiral branch direction in this article. The checkerboard structure can also be oriented and / or twisted so that two or more spiral branches occur. The transition of a spiral branch or multiple spiral branches after one revolution of the correction tool is preferably continuous. This structure with the spiral branch that stretches spirally can also be described as the superposition of the addition of two sub-waves mathematically, and wherein the sub-wave has a wavefront that extends obliquely in a manner projected onto the ring. If the number of spiral branches is less than twice the order in the direction of the spiral branches, the structure can be described by additive superposition, wherein the obliquely extending wavefront of the first wavelet has a positive slope and the obliquely extending wavefront of the second wavelet has a negative slope, wherein the first wavelet has an order in the circumferential direction that is greater than the order in the circumferential direction of the second wavelet by the number of spiral branches. If the number of spiral branches is greater than twice the order in the direction of the spiral branches or is equal to twice the order in the direction of the spiral branches, the structure can be described by additive superposition, wherein the obliquely extending wavefronts of the first wavelet and the second wavelet either both have a positive slope or both have a negative slope, wherein the first wavelet has an order in the circumferential direction that is greater than the order in the circumferential direction of the second wavelet by twice the order in the direction of the spiral branches.

[0028] In another aspect, the present invention provides a method for manufacturing the above-mentioned correction tool. The method for manufacturing comprises:

[0029] A substrate for the coating of a modified tool manufactured by the positive method, and

[0030] The trimming side profile is produced in a targeted manner by means of an adjusting tool, in particular a rotating adjusting disk, which is perpendicular to the trimming side surface.

[0031] Preferably, a narrow rotating adjusting disk is used here, for example an adjusting disk which has a head rounding on its outer circumference (i.e. the convexity of the side surface of the adjusting disk in the axial direction) with a rounding radius, which corresponds to at most one quarter of the radial wavelength in the radial direction, wherein the radial wavelength of the wave period corresponds to the waviness in the radial direction.

[0032] The targeted generation of the trimming side modification can include, in particular:

[0033] driving the dressing tool to rotate about a dressing rotation axis;

[0034] driving the adjusting tool to rotate about an adjusting rotation axis of the adjusting tool, and

[0035] The adjusting tool is advanced relative to the correcting tool in a direction having a portion running normal to the trimming side surface in order to produce the trimming side profile by removing material from the trimming side surface.

[0036] The material removal process can produce an adjustment track in the trimming side surface, which corresponds to a wave trough and has a width corresponding to half the radial wavelength in the radial direction. However, the width of the adjustment track can also be less than half the radial wavelength of the desired trimming side modification in the radial direction. In this case, multiple adjacent adjustment tracks may be necessary to produce a complete wave trough.

[0037] Instead of a narrow adjusting disk, the adjusting tool can also have a ribbed outer circumference with at least two adjusting ribs, wherein each adjusting rib has a head rounding with a rounding radius that corresponds to at most one-quarter of the radial wavelength in the radial direction, and wherein each adjusting rib can generate a respective adjusting track in the trimming side surface. In this case, the adjusting tool can generate multiple adjusting tracks simultaneously, thereby producing the entire pattern of the trimming side profile in a single pass, depending on the number of adjusting ribs. Here, too, the orientation of the wave front can be adjusted, as in the case of an adjusting disk (which corresponds to a adjusting tool with a single adjusting rib), by kinematically moving the adjusting tool relative to the correction tool.

[0038] The feed movement of the setting tool relative to the correction tool can be achieved by a spatial movement of the setting tool and / or a spatial movement of the correction tool. The feed movement of the setting tool in a direction normal to the trimming side surface, or the resulting feed position, can oscillate at a feed frequency that is a predetermined, fixed ratio to the rotational frequency of the correction tool. As a result, the material removal can vary along the setting trajectory, resulting in a corresponding waviness along the setting trajectory.

[0039] Depending on the trimming side profile, the targeted production of the trimming side profile relative to the oscillating feed movement can alternatively or additionally include:

[0040] A discontinuous or continuous adjusting axial movement occurs along the adjusting rotation axis.

[0041] “Continuously” in this context means that the adjusting axial movement is carried out while the adjusting tool is in contact with the correcting tool, so that material removal takes place during the adjusting axial movement.

[0042] “Discontinuous” in this context means that the adjusting axial movement is carried out during which the adjusting tool is not in contact with the correcting tool, so that no material is removed during the adjusting axial movement.

[0043] The adjustment axial movement should be understood as the relative movement along the adjustment rotation axis between the correction tool and the adjustment tool. Here, the adjustment tool and / or the correction tool can be driven to perform the adjustment axial movement.

[0044] According to the trimming side modified portion, targeted generation of the trimming side modified portion may further include:

[0045] By means of a discontinuous and / or continuous adjusting axial movement along the adjusting rotation axis, a plurality of adjusting paths intersecting at a predetermined angle are produced on the dressing side surface by means of the adjusting tool.

[0046] The feed position of the adjusting tool relative to the dressing side surface can have a constant value in a direction running normal to the dressing side surface, or the feed movement or feed position of the adjusting tool can oscillate at a feed frequency.

[0047] Thus, for example, a structure can be produced in which the wave troughs intersect and the intermediate material region of the trimmed side surface forms a ridge. Depending on the orientation of the intersecting wave troughs on the trimmed side surface, the ridge can be arranged along a spiral branch extending helically on a circular ring.

[0048] Alternatively, the method for manufacturing a correction tool may include:

[0049] The correction tool is manufactured by the negative method, wherein the negative method includes:

[0050] The negative mold is produced by turning out a negative matrix;

[0051] Lathe a targeted negative profile into the turned negative die, so that the negative profile leads to a trimming of the side profile, and / or

[0052] During turning, the negative basic body is mechanically and / or hydraulically clamped, so that after the mechanical clamping is released, the turned negative mold has a negative profile which results in a trimming side profile.

[0053] The targeted negative shaping can be turned into the turned negative die by means of a suitable machining tool, in particular a turning tool, which can be moved relative to the negative die, preferably along its axis of rotation.

[0054] In particular, the targeted generation of the negative deformation can include:

[0055] driving the female mold for rotation about the female mold rotation axis at a rotational frequency;

[0056] The turning tool is positioned such that it produces a negative track in at least one inner side of the negative die.

[0057] In another aspect, the present invention provides a method for dressing a grinding worm for generating a workpiece with pre-formed teeth. The method for dressing a grinding worm for generating a workpiece with pre-formed teeth comprises:

[0058] The grinding worm is dressed by means of the aforementioned dressing tool in such a way that the dressing-side reshaping results in a worm reshaping on the grinding worm side of the worm thread of the grinding worm.

[0059] In this case, a predetermined fixed rotational angle coupling can exist between the dressing tool and the grinding worm in order to selectively generate a periodic worm profile along the worm thread on the grinding worm side. In this case, the worm profile is a compressed image of the dressing-side profile with a constant compression factor, wherein the compression factor is dependent on the speed ratio between the rotation of the dressing tool and the rotation of the grinding worm.

[0060] Alternatively, a predefined, time-variable rotational angle coupling can be provided between the dressing tool and the grinding worm in order to selectively generate a non-periodic worm profile along the worm thread on the grinding worm side. In this case, the dressing-side profile is mapped into the worm profile with a non-constant compression factor.

[0061] In another aspect, the present invention provides a method for dressing a grinding worm for generating a workpiece with prefabricated teeth, the method comprising, in particular, the above method, the method comprising:

[0062] defining a desired worm modification on a grinding worm side of a worm thread of the grinding worm;

[0063] For a selected fixed or variable rotational angle coupling between the dressing tool and the grinding worm, the desired worm profile is calculated back onto the corresponding dressing-side profile of the dressing tool;

[0064] In particular, a dressing tool having a corresponding dressing side deformation is produced by means of the method described above;

[0065] The grinding worm is dressed by means of a dressing tool coupled with a selected fixed or variable rotational angle, wherein the dressing side profiles produce the desired worm profile along the worm thread.

[0066] In another aspect, the present invention provides a method for producing a modified surface structure on a tooth flank of a workpiece having prefabricated teeth. The method for producing a modified surface structure on a tooth flank of a workpiece having prefabricated teeth comprises:

[0067] Dressing a grinding worm suitable for generating workpieces with prefabricated teeth by means of the above method;

[0068] driving the grinding worm to rotate about the worm axis;

[0069] driving the workpiece with the preformed teeth to rotate about the workpiece axis;

[0070] Producing a relative movement between the grinding worm and the workpiece with the pre-formed teeth in a displacement direction parallel to the worm axis at a displacement feed rate ("displacement movement"), and

[0071] A relative movement is generated between the grinding worm and the workpiece with the pre-formed teeth in an axial direction parallel to the workpiece axis at an axial feed speed ("axial feed movement"),

[0072] The grinding worm and the pre-toothed workpiece are in developing engagement, and the displacement feed rate and the axial feed rate are in a predetermined diagonal ratio, so that the worm modification is reflected onto the tooth flanks of the pre-toothed workpiece and the surface structure of the tooth flanks is modified in a targeted manner.

[0073] The diagonal ratio here refers to the ratio of the displacement feed rate of the grinding worm in the displacement direction to the axial feed rate of the grinding worm in the axial direction parallel to the workpiece axis. The diagonal ratio can be zero or not. When the diagonal ratio is zero, a profile modification along the height direction of the tooth flank is produced on the tooth flank. When the diagonal ratio is not zero, the resulting modification of the surface structure of the tooth flank can be a topological modification, i.e., a modification with a component not only in the height direction but also in the width direction of the tooth flank.

[0074] Additionally, the method may also include generating a relative movement between the grinding worm and the workpiece with the prefabricated teeth in a radial direction perpendicular to the workpiece axis ("radial feed movement"). This allows additional modifications to be superimposed on the above-described modifications to the surface structure of the tooth flanks. In the case of conical workpieces, the radial feed movement and the axial advance movement can be coupled depending on the cone angle of the conical toothing.

[0075] The worm modification causes a change in the penetration depth between the grinding worm and the workpiece with pre-formed teeth during the generating process, thereby generating a tooth flank waviness along a contact path on the tooth flank, wherein the contact path corresponds to the following line: the contact point between the grinding worm and the workpiece with pre-formed teeth in generating engagement moves along the tooth flank during the generating process.

[0076] If the correction tool has a checkerboard-like structure, which is oriented so that the troughs and peaks that are respectively adjacent in the circumferential direction are arranged along a spiral branch that extends spirally on a circular ring, thereby forming a spiral waviness, then during dressing, a fixed rotational angle coupling can be selected between the correction tool and the grinding worm, so that the spiral branch is mapped onto the worm contact path on the grinding worm side, wherein the worm contact path corresponds to the following line: the contact point between the grinding worm and the workpiece with prefabricated teeth in the generating meshing moves on the grinding worm side during the generating process.

[0077] The helical waviness occurring along the helical branches on the dressing flank surface can thus be transferred in a targeted manner along the contact path by the dressing tool via the grinding worm to the tooth flank.

[0078] In some embodiments, the targeted movement of the grinding worm in the displacement and axial directions relative to the workpiece with the pre-toothed portion is superimposed with uncontrolled, in particular randomly occurring, additional movements that lead to uncontrolled variations in the penetration depth. Such uncontrolled additional movements can be caused, for example, by unavoidable vibrations of the generating grinding machine with which the generating process is performed.

[0079] By deliberately varying the penetration depth of the worm profile of the grinding worm, which has been dressed as described above, a suitable load-bearing pattern can be generated on the tooth flanks. This load-bearing pattern can be made more diffuse by superimposing it on an uncontrolled variation of the penetration depth, which can lead to an optimization of the noise characteristics. In this way, for example, unavoidable vibrations can be specifically contributed to improving the noise characteristics.

[0080] Preferably, due to the dressing of the grinding worm as described above, the targeted variation of the penetration depth has a modulation amplitude which lies in the range between 0.2 and 5 times the fluctuation measure for the uncontrolled deviation of the penetration depth.

[0081] The fluctuation measure corresponds in particular to the standard deviation or the interquartile range of the uncontrolled deviations of the penetration depths,

[0082] In particular, a fluctuation measure of the uncontrolled change in the penetration depth is determined, and the modulation amplitude and thus in particular the amplitude of the worm profile and thus in turn in particular the amplitude of the dressing-side profile are selected in a targeted manner depending on the determined fluctuation measure.

[0083] In another aspect, the present invention provides an adjustment device comprising:

[0084] an adjusting tool, in particular a narrow adjusting disk, clamped on an adjusting spindle, i.e. an adjusting disk which has, on its outer circumference, a head rounding with a rounding radius which corresponds to at most one quarter of the radial wavelength in the radial direction, wherein the radial wavelength of the wave period corresponds to the waviness in the radial direction;

[0085] a dressing spindle configured to receive a dressing tool for rotation about the dressing rotation axis;

[0086] An adjustment control device is configured to move the adjustment tool relative to the correction tool so that the correction tool is provided with the dressing-side deformation portion as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] The following describes preferred embodiments of the present invention based on the accompanying drawings, which are only used for illustration and should not be interpreted as limiting.

[0088] Figure 1A shows a schematic end view of the correction tool in a projection plane perpendicular to the dressing rotation axis of the correction tool;

[0089] Figure 1B showing a projection of the trimmed side surface in unfolded form;

[0090] Figure 2 A first example pattern of a trimmed side modification is shown;

[0091] Figure 3 A second example pattern of a trimmed side modification is shown;

[0092] Figure 4 A third example pattern of a trimmed side modification is shown;

[0093] Figure 5 A fourth example pattern of a trimmed side modification is shown;

[0094] Figure 6A A fifth example pattern of a trimmed side modification is shown;

[0095] Figure 6B The first wavelet pattern is shown for additional mathematical description Figure 6A The fifth example pattern of;

[0096] Figure 6C A second wavelet pattern is shown for additional mathematical description Figure 6A The fifth example pattern of;

[0097] Figure 7A A first exemplary arrangement of spiral branches on a trimmed side surface is shown;

[0098] Figure 7B A second exemplary arrangement of two spiral branches on a trimmed side surface is shown;

[0099] Figure 7C A third exemplary arrangement of three spiral branches on a trimmed side surface is shown;

[0100] Figure 7D A sixth example pattern of a trim side modification with two helical branches is shown;

[0101] Figure 7E showing a sixth example pattern transferred onto the projection of the trimmed side surface;

[0102] Figure 8A shows an adjustment device according to one embodiment of the present invention;

[0103] Figure 8B An enlarged cross-sectional view of a portion of an adjusting tool having a plurality of adjusting ribs is shown;

[0104] Figure 9 Shows a turned negative die for producing a correction tool according to the present invention;

[0105] Figure 10A The female mold is shown clamped according to the deformation device;

[0106] Figure 10B Shown is a loose and turned negative die for producing a correction tool according to the invention;

[0107] Figure 11 A projection showing a grinding worm side of a worm thread of a grinding worm in developed form;

[0108] Figure 12 A schematic diagram showing a generating grinding machine, and

[0109] Figure 13 Show Figure 12 An enlarged part of the image. DETAILED DESCRIPTION

[0110] Correction tool

[0111] exist Figure 1A Schematically shows an end view of a correction tool 33, wherein the correction tool 33 has a dressing side surface 331, which forms a ring in a projection plane perpendicular to the dressing rotation axis A of the correction tool 33, wherein the ring defines a radial direction with a radial coordinate r and an angular coordinate circumferential direction, and wherein the ring has an inner radius r A .

[0112] exist Figure 1B , the circular ring is schematically shown in expanded form, having a profile height d in the radial direction and a length of 2π in the circumferential direction.

[0113] Figures 2 to 6A Different waveform patterns are shown exemplarily, and the waveform patterns may have Figure 1B The specifically produced finishing side modification on the finishing side surface is shown in FIG, wherein the wave peaks are schematically shown here in a lightly shaded manner and the wave troughs in a darkly shaded manner.

[0114] The following describes how to mathematically describe the two-dimensional waveform pattern. For this purpose, a pattern rectangle having a pattern height Δr'' in the height direction, hereinafter referred to as the radial direction, and a pattern length 2π in the longitudinal direction, hereinafter referred to as the circumferential direction, is used. The pattern can be described as the angular coordinates relative to the pattern rectangle. The two-dimensional real-valued Fourier series associated with the radial coordinate r′∈[0,Δr′] (i.e., with two real-valued variables and r′) in real-valued Fourier series:

[0115]

[0116] The circumferential frequency component k m =mk1 is unitless, and the radial frequency component R n =nR1 has the unit [1 / mm]. In the definition, the angular coordinates of the pattern rectangle are Corresponding to the angular coordinates of the ring mentioned above The radial coordinate r′ of the coordinate system of the pattern rectangle can also be expressed as the radial coordinate r in the coordinate system of the ring according to a linear transformation, for example, via the relationship r=r′+r A , where r A Indicates the inner radius of the ring.

[0117] Subscript and is an integer, so the circumferential frequency component k m Or radial frequency component R nIs the circumferential fundamental frequency k1 = 1 or the radial fundamental frequency An integer multiple of .

[0118] The Fourier coefficients indicating the amplitude and phase of the corresponding frequency components are expressed as c n，m The Fourier coefficients can usually be written in complex form as where a n，m is the real part, b n，m is the imaginary part, A n，m is the amplitude, and θ n，m is the phase. The complex conjugate coefficient is The imaginary part determines in particular the phase of the pattern. If, as here, a continuous transition (2π periodicity) is assumed after one revolution of the correction tool, the phase of the pattern in the circumferential direction is unimportant.

[0119] By the above-selected definition of the radial fundamental frequency, the pattern repeats periodically in the radial direction with a pattern period of Δr′.

[0120] Trimming side modification section The phase in the radial direction on the trimmed side surface 331 can be arbitrarily selected and is expressed as the corresponding linear coordinate translation from the radial coordinate r′ of the pattern rectangle to the radial coordinate r on the trimmed side surface. The profile height d, over which the trimming side modification extends, can correspond to the pattern period Δr′, or can be selected to be smaller or larger (since the pattern continues periodically with a pattern period of Δr′). In other words, this means that any radial portion of the periodic example pattern described mathematically below can be applied to the correction tool as a trimming side modification.

[0121] Therefore, the phase of the pattern on the pattern rectangle is unimportant, and to simplify the description, the Fourier coefficients c can be chosen complex conjugate on the pattern rectangle. n，m and c -n，-m ,Right now

[0122] Figuratively speaking, the trimming side modification can be described as a portion of a wavy pattern on a rectangular pattern, or as a portion of a superposition of two or more wavy sub-patterns on a rectangular pattern, wherein each of the wavy sub-patterns may have periodic waviness in the radial and / or circumferential directions. It should be noted that the absolute phase of the resulting pattern is not important. If multiple wavy sub-patterns are superimposed to describe the resulting pattern, the relative phases of the sub-patterns are important.

[0123] Hereinafter, for each of the waveform patterns / sub-patterns, the number of wave periods in the radial direction on the pattern rectangle is expressed as an order N in the radial direction, and the number of wave periods in the circumferential direction is expressed as an order M in the circumferential direction. The wave period in the radial direction has a radial wavelength λ r′ , and the wave period in the circumferential direction is expressed as the offset angle (“wavelength in the circumferential direction”). Since the circumferential fundamental frequency k1=1 has been chosen, the order M in the circumferential direction corresponds to the subscalar value |m|, and since the radial fundamental frequency has been chosen So the order N in the radial direction corresponds to the subscalar value |n|.

[0124] exist Figure 2 In the embodiment shown in FIG, the pattern has a wavefront in the form of a line of constant phase, wherein the wavefront forms a continuous straight line when projected onto the expanded ring. Figure 2 As shown, the line is inclined at an inclination angle α relative to the circumferential direction of the development and is offset at an angle α in the circumferential direction. In order to make the pattern of the trimming side modification portion continue periodically after one revolution, only discrete values ​​of the inclination angle α are possible, namely

[0125] in

[0126] The line of constant phase where α < 0° has a negative slope (i.e., Figure 2 If the line of constant phase has a negative slope, then the following frequency components are {R n , k m} has Fourier coefficients not equal to zero:

[0127] {R n＝+N , k m＝+M} and {R n＝-N , k m＝-M}

[0128] Conversely, if the line of constant phase has a positive slope, then the following pairs of frequency components have Fourier coefficients that are not equal to zero:

[0129] {R n＝+N , k m＝-M} and {R n＝-N , k m＝+M}

[0130] The waveform shape does not necessarily have to be a pure sinusoidal shape, so other Fourier coefficients may also be non-zero. In particular, higher-order harmonics of the Fourier coefficients mentioned above may be non-zero, i.e., Fourier coefficients where n is an integer multiple of N and m is an integer multiple of M. In this case, the relative phase angles of the higher-order harmonics with respect to the lowest-order frequency must also be considered, as this significantly influences the resulting pattern.

[0131] The following table summarizes Figure 2 Parameters of the trimming side modification part in:

[0132]

[0133] Specifically applicable to Figure 2 Pattern:

[0134] All other Fourier coefficients are zero.

[0135] exist Figure 3 In the case of the inclination angle α, it is exactly 90°, that is, the wavefront of the trimming side modification is radially oriented in a manner projected onto a circular ring. This situation corresponds to the radial frequency component R in the radial direction that is not equal to zero. n A complex Fourier series with no coefficients not equal to zero. The trimming side modification shown here extends continuously in the circumferential direction, i.e. the wave-shaped trimming side modification has an integer wave period (2π periodicity) over a single revolution of the correction tool. The following table summarizes Figure 3 Parameters of the trimming side modification part in:

[0136]

[0137]

[0138] Specifically applicable to Figure 3 Pattern:

[0139] All other Fourier coefficients are zero.

[0140] exist Figure 4 The tilt angle α is exactly 0°, that is, the wavefront extends straightly parallel to the circumferential direction and forms a wave with a radial wavelength λ in the radial direction. r This situation corresponds to the circumferential frequency component k that is not equal to zero in the circumferential direction. m The complex Fourier series does not have coefficients not equal to zero. The following table summarizes Figure 4 Parameters of the trimming side modification part in:

[0141]

[0142] Specifically applicable to Figure 4 Pattern:

[0143] All other Fourier coefficients are zero.

[0144] exist Figure 5 In the embodiment shown in FIG, the two-dimensional complex Fourier series for the radial frequency component R not equal to zero is n And for the circumferential frequency component k not equal to zero m The coefficients are not equal to zero, so that the modified portion of the wave-shaped trimming side forms a checkerboard-like structure with peaks and troughs arranged staggered with each other when projected onto the unfolded ring. Mathematically, Figure 5 The pattern in can be described as the first sub-wave and the second wavelet The addition of superposition,

[0145]

[0146] The first wavelet and the second wavelet have the same order M in the circumferential direction and the same order N in the radial direction, but the line of constant phase has a negative slope in the first wavelet and a positive slope in the second wavelet.

[0147] exist Figure 5 In the embodiment, adjacent troughs and crests are offset from each other, thereby forming radial waviness along radial paths R1 and R2 extending parallel to the radial direction. Figure 5 In the example shown in FIG, the circumferential paths U1 and U2 are offset by exactly 180°, thereby forming circumferential waviness along circumferential paths U1 and U2 extending parallel to the circumferential direction, wherein the circumferential paths U1 and U2 are spaced apart from each other in the radial direction by half a radial wavelength λ. r′ / 2. The following table summarizes Figure 5 Parameters of the trimming side modification part in:

[0148]

[0149] Specifically applicable to Figure 5 Pattern: as well as All other Fourier coefficients are zero.

[0150] Figure 6A shows a spiral pattern which can be mathematically described as Figure 6B The first wavelet shown in and in Figure 6C The second wavelet shown in The additive superposition of :

[0151]

[0152] and Figure 5 compared to, Figure 6A The radial waviness of adjacent radial paths R1 and R2 is offset by a value different from 180°. Thus, circumferentially adjacent troughs and crests are arranged along a spiral branch S1 extending spirally around the ring, thereby forming a spiral waviness. Hereinafter, the number of wave periods along a spiral branch S1 is referred to as the order L in the spiral branch direction.

[0153] The lead height of the helical branch over one revolution of the correction tool is calculated as half the radial wavelength λ r′ / 2 and the number of spiral branches Here, the spiral branch forms a straight line inclined relative to the circumferential direction on the unfolded ring, where the inclination angle α (similar to Figure 2 The situation in ( ) can be expressed as:

[0154]

[0155] In order to make the pattern of the trimming side deformation continue periodically after one revolution, only discrete values ​​are possible for the lead height. If the lead height corresponds to half the radial wavelength λ r′ / 2, the pattern can always continue periodically.

[0156] Therefore, in order to ensure a continuous transition of the helical branch after one revolution of the correction tool, two cases are distinguished:

[0157] 1. The freely chosen order L in the direction of the helical branch is an integer: in this case, the lead height of the helical branch must correspond to half the radial wavelength λ r′ An even multiple of / 2, i.e. the number of spiral branches s It is an even number.

[0158] 2. The freely chosen order L in the direction of the helical branch is a half-integer: in this case, the lead height of the helical branch must correspond to half the radial wavelength λ r′ An odd multiple of / 2, i.e. the number of spiral branches s An odd number.

[0159] exist Figure 6A In the helical branch direction, the order is L = 5.5 and the lead height is exactly λ r′ / 2, because there is exactly one spiral branch, namely i s =1.

[0160] In order to obtain a specific order L for the spiral wave in the direction of the spiral branch, it is necessary to The order M of the wave degree in the circumferential direction W，1 And for the second wavelet The order M of the wave degree in the circumferential direction W，2 Applicable:

[0161]

[0162] If applicable Then the second wavelet has a slope with a sign opposite to the sign of the slope of the first wavelet. Then the second wavelet has a slope with the same sign as the first wavelet. The following table summarizes Figure 6A Parameters of the trimming side modification part in:

[0163]

[0164] The first wavelet With a wavefront with a negative slope ( Figure 6B ), and the second wavelet With a wavefront with a positive slope ( Figure 6C ). Therefore, it is specifically applicable to Figure 6A Pattern:

[0165] and All other Fourier coefficients are zero.

[0166] exist 7A to 7C Schematically shows how the helical branches can be arranged on the dressing side surface 331 of the dressing tool 33 . Figure 7A The following example is shown: in this example, exactly one spiral branch S1 is formed on the trimmed side surface 331, i.e. s =1.

[0167] exist Figure 7B In the embodiment, two spiral branches S1 and S2 are formed on the trimmed side surface 331, i.e. s =2, where the spiral branches S1 and S1 are offset in the circumferential direction by an angle The offset angle is π in the example.

[0168] exist Figure 7C There are three spiral branches S1, S2, and S3, wherein the spiral branches S1, S2, and S3, i.e. s =3, in which the circumferential direction is offset by an angle Offset, the offset angle is 2π / 3.

[0169] exist Figure 7D and Figure 7EAnother example pattern is shown in FIG. 1 according to a specific number. In the example, the number of spiral branches is i s =2, radial wavelength λ r′ =15 mm, the pattern period is Δr′=30 mm, the order in the spiral branch direction is L=50, and the spiral branches S1 and S2 extend in the counterclockwise direction. The spiral waviness has an amplitude of A=3.5 μm.

[0170] Thus, the order of the waviness of the first wavelet 1 and the second wavelet 2 in the circumferential direction is calculated according to the following equation:

[0171] Wavelet 1: M W，1 =1+L=51

[0172] Wavelet 2: M W，2 =|1-L|=49

[0173] The order in the radial direction is:

[0174] Wavelet 1:

[0175] Wavelet 2:

[0176] The Fourier coefficients are not equal to zero, in this case they are real Fourier coefficients, so:

[0177]

[0178] The checkerboard-like waviness can be described by the following equation:

[0179]

[0180] Through the relationship (2·cos(x)=e ix +e -ix ), It can also be converted into real number notation:

[0181]

[0182] The pattern according to the formula with two spiral branches S1, S2 exist Figure 7D In Figure 7E middle, Figure 7D The part of the pattern in the figure can be regarded as the modified part of the trimming side projected onto the ring. The pattern here extends over a profile height d<Δr′ (where d=20 mm), and the following applies: where r A =30mm.

[0183] Correction tool manufacturing

[0184] The dressing tool with the above-explained dressing side deformation can be produced both by means of a male method and by means of a female method.

[0185] Yang method

[0186] In the positive method, a base body, preferably made of steel, is provided, which is coated with hard material particles, typically diamond particles, preferably electroplated. Methods for producing base bodies coated with hard material particles in the positive method are known from the prior art, for example from the publications EP 2535145 A2 and EP 2835220 A1, the disclosures of which are hereby fully incorporated by reference.

[0187] Figure 8A A schematic diagram illustrates a setting device 50 according to one embodiment of the present invention. The setting device includes a dressing tool 33 (shown in cross-section here), wherein a base body 330 comprises a hollow cylinder that is clamped to the dressing spindle 32 and can be driven to rotate about a dressing axis of rotation A. A circular disk with a dressing side that tapers radially relative to the dressing axis of rotation A extends around the hollow cylinder. Hard material particles applied to the dressing side form a dressing side surface 331. To provide the dressing side surface 331 with a dressing side profile, the dressing side surface is machined using the setting tool 51. In the example schematically illustrated here, the setting tool 51 is a narrow setting disk that can rotate about a setting axis of rotation K, which extends parallel to the dressing side to be machined, and can be moved in a direction normal to the dressing side surface 331 and parallel to the setting axis of rotation K. The setting disk preferably has an abrasive coating with bonded hard material particles having a hardness similar to or greater than that of the hard material particles of the dressing tool coating. In order to produce the trimming side modified portion, the correction tool is driven to rotate about the trimming rotation axis A, and the adjustment tool 51 is driven to rotate about the adjustment rotation axis K. Then, the rotating adjustment disk is fed so that it comes into contact with the trimming side surface 331 and thereby performs material removal of the trimming side surface 331. Figure 8A In the example shown in , the feed movement is performed parallel to the normal to the trimmed side surface 331 .

[0188] The feed movement of the adjustment tool 51 or the resulting feed position perpendicular to the dressing side surface can be adjusted at a feed frequency f K Oscillation, the feed frequency and the correction tool f A The rotation frequency is coordinated to produce the desired waviness, and in addition, a discontinuous or continuous adjustment axial movement can be performed along the adjustment rotation axis K. In order to obtain a desired wave shape of order M in the circumferential direction, the following are particularly suitable:

[0189] f K =Mf A

[0190] The adjustment device comprises an adjustment control device 53 which is designed to adjust the rotational frequency f of the correction tool. A and feed frequency f K The feed motion of the setting tool 51 relative to the correction tool 33 is coordinated with each other and controlled.

[0191] Instead of a narrow adjusting disk, the adjusting tool 51 can also have a ribbed outer circumference. Figure 8B By way of example, an enlarged detail of a cross section through an adjusting tool 51 is shown, which has three adjusting ribs 511, wherein the adjusting ribs 511 each have a head rounding with a rounding radius corresponding to the radial wavelength λ in the radial direction. r′ One quarter of the trimming side surface, and each of the adjustment ribs 511 can generate an adjustment track in the trimming side surface respectively.

[0192] Example

[0193] The following explains Figures 2 to 6A The production of the trimming side modification portion is exemplified in FIG.

[0194] Figure 2 Production of the trimming side modification part:

[0195] A wave front extending on the unfolded ring at an angle of inclination α relative to the circumferential direction can be generated as follows:

[0196] Feeding the adjustment tool to a constant feed value in a direction normal to the trimmed side surface;

[0197] During at least one revolution of the correction tool 33 , a continuous adjusting axial movement of the adjustment tool occurs along the adjustment axis of rotation K at a constant axial speed.

[0198] The continuous adjusting axial movement can be performed here either from the inside out or from the outside in with respect to the radial direction of the correction tool 33. A The desired increase in the tilt angle α is accompanied by a constant increase in the axial speed, remaining constant.

[0199] For Figure 2 In the example specifically shown in FIG, where the tilt angle α is chosen so that the wavefront, projected onto the unrolled ring, has a slope of the magnitude Δr′ / 2π, the axial velocity must therefore have, for a fixed value of the rotational frequency of the correction tool, the following velocity component projected onto the radial direction of the correction tool:

[0200] v r =Δr′f A .

[0201] exist Figure 2 In the example shown in FIG, for each revolution of the correction tool an adjustment track is generated in the dressing side surface extending obliquely over the entire length of the unfolded ring, said adjustment track corresponding to the trough (at Figure 2 darkly shaded in the middle), thus having a value corresponding to half the radial wavelength λ r′ / 2 width. In order to generate Figure 2 The other troughs shown in FIG, the adjustment tool is repositioned after each rotation of the correction tool, but is shifted circumferentially by the circumferential wavelength relative to the unfolded ring. If an adjusting tool 51 with a plurality of adjusting ribs 511 is used, so that all desired adjusting paths are produced in a single revolution, repositioning of the adjusting tool 51 can also be omitted.

[0202] Figure 3 Production of the trimming side modification part:

[0203] exist Figure 3 In the embodiment, the wave-shaped trimming side modification has a wave front which is radially oriented in a manner projected onto a circular ring. In order to produce the trimming side modification, the feed position of the tool is adjusted to a feed frequency f K Normal to the oscillation of the dressing side surface, the feed frequency is related to the rotation frequency f of the correction tool A In order to obtain a desired wave-shaped trimming side profile of order M in the circumferential direction, the following relationship must be met:

[0204] f K =Mf A

[0205] The adjusting tool 51 thus generates an adjusting track extending in the circumferential direction with a corresponding waviness of order M.

[0206] Depending on the profile height d along which the trimming-side profile of the ring is to extend and the width of the individual adjustment paths, the adjustment tool must be repositioned at a plurality of different positions along the adjustment rotation axis K. In order for the adjustment paths extending adjacently in the radial direction to form a continuous, radially linear wave front, it must be ensured that the oscillating feed motion of the adjustment tool has a phase synchronization with the rotation of the correction tool 33 when the adjustment tool is placed in a new position, so that the waviness of the new adjustment path runs in phase with the waviness of the previously generated adjustment path.

[0207] Alternatively, it is also conceivable to produce a continuous adjusting axial movement of the adjusting tool at a constant axial speed along the adjusting axis of rotation K, rather than individually repositioning the adjusting tool along the adjusting axis of rotation after one revolution of the correction tool. However, in order to form a wave front extending essentially linearly in the radial direction, the axial speed must be selected such that the distance covered by the adjusting tool after one revolution of the correction tool along the adjusting axis of rotation K corresponds at most to the width of the adjustment path.

[0208] Figure 4 Production of the trimming side modification part:

[0209] exist Figure 4 The trimming side modification shown in FIG can be created by feeding the adjustment tool in the direction normal to the trimming side surface to a constant feed value, wherein (with Figure 2 In contrast to the creation of the trimming-side deformations in the trimming tool, a continuous axial adjustment movement along the trimming axis of rotation K is not performed, thereby generating an adjustment path extending parallel to the circumferential direction. After at least one revolution of the correction tool, the adjustment tool is repositioned at a plurality of different positions along the trimming axis of rotation K to generate new, radially adjacent adjustment paths, thereby generating a wave front that, when projected onto the expanded annulus, extends linearly parallel to the circumferential direction. Repositioning the adjustment tool 51 can also be omitted if an adjustment tool 51 having multiple adjustment ribs 511 is used, so that all desired adjustment paths are generated in a single revolution.

[0210] Figure 5 Production of the trimming side modification part:

[0211] exist Figure 5 The trimming side modification shown in FIG can be produced by respectively Figure 3 and Figure 4 The trimming side modification section shown in FIG is produced by superposition of the steps required: Figure 5 The trimming side modification section shown in FIG adjusts the feed position of the tool to match the rotation frequency f of the tool. A Coordinated feed frequency f K The surface oscillates normally to the trimming side, during which no adjustment axial movement occurs along the adjustment rotation axis K. In order to obtain a desired trimming side profile of wave form of order M in the circumferential direction, the following relationship must be met:

[0212] f K =Mf A

[0213] The adjusting tool 51 thus generates an adjusting path having a circumferential waviness of order M, which extends in the circumferential direction.

[0214] After one rotation of the correction tool 33, the adjustment tool 51 is repositioned at a plurality of different positions along the adjustment rotation axis K to generate new adjustment paths adjacent in the radial direction, which have half the radial wavelength λ r′ / 2. This results in circumferential waviness along circumferential paths U1, U2 running parallel to the circumferential direction. The oscillating feed motion of the adjusting tool has a phase that is synchronized with the rotation of the correction tool 33 so that the resulting circumferential waviness is shifted by 180° relative to one another. If an adjusting tool 51 with multiple adjusting ribs 511 is used so that all desired adjustment paths are generated in a single rotation, repositioning of the adjusting tool 51 can also be omitted.

[0215] Figure 6A Production of the trimming side modification part:

[0216] In order to produce Figure 6A The trimming side modification shown in Figure 2 As in the case of the trimming side deformation in FIG. 1 , a continuous adjustment axial movement of the adjustment tool is also produced along the adjustment rotation axis K at a constant axial speed over at least one revolution of the correction tool 33, but here the adjustment tool is moved in a direction normal to the trimming side surface (in the direction of the trimming side surface). Figure 2 In contrast to the situation in the example above, the tool is not fed to a constant feed value, but the feed position of the tool is adjusted instead with a feed frequency f. K Normal to the oscillation of the dressing side surface, the feed frequency is related to the rotation frequency f of the correction tool A This results in a trimming side profile in which wave troughs and wave crests adjacent in the circumferential direction are arranged along a spiral branch S1 extending spirally on a circular ring, wherein the spiral branch S1 on the unfolded circular ring forms a straight line inclined relative to the circumferential direction.

[0217] In order to obtain a desired order L of wave-shaped trimming-side modification in the spiral branching direction, the following relationship must be satisfied:

[0218] f K =Lf A

[0219] In order to generate further spiral branches S2, S3, ..., the adjusting tool is respectively repositioned after the spiral branches have been generated, but in the circumferential direction with respect to the unfolded ring. Moved the offset angle up In a preferred variant, the offset angle Choose such that the following relationship is satisfied:

[0220]

[0221] where i sIndicates the number of spiral branches.

[0222] If an adjusting tool 51 with a plurality of adjusting ribs 511 is used, so that all desired adjusting paths are produced in a single revolution, repositioning of the adjusting tool 51 can also be omitted.

[0223] The steps used to produce the examples described can of course be combined to produce further trim side modifications not explicitly shown here.

[0224] In particular, patterns are conceivable in which successive wave troughs intersect at any predetermined angle. For example, purely radially oriented wave troughs can intersect purely circumferentially oriented wave troughs at an angle of 90°, projected onto the ring. Alternatively, the intersecting wave troughs can also extend obliquely on the trimmed side surface.

[0225] Correction of tool rotation frequency f A and / or adjust the tool feed frequency f K And / or the adjustment axial movement can be varied in time during machining in order to produce targeted trim side modifications with more complex patterns.

[0226] Yin method

[0227] Alternatively, the correction tool having the trimming side modifications described above can be produced using a negative method. To this end, a negative base body, preferably made of aluminum or graphite, is provided. This base body is turned into the negative mold of the desired correction tool using a turning tool. Negative methods for producing correction tools are known from the prior art, for example from EP 1 110 671 A2, the disclosure of which is incorporated herein by reference in its entirety.

[0228] In order to obtain a desired trimming side modification on the trimming side surface 331 , a corresponding female modification can be turned into the female modification in a targeted manner. Figure 9 A schematic sectional view of a die 60 is shown, wherein the die 60 is mounted rotatably about a die axis of rotation D and has an inner side 61 which tapers radially outwards relative to the die axis of rotation D.

[0229] exist Figure 9 In the figure, a turning tool 70 is schematically shown, which is introduced into the die 60 and has a turning tool tip 71 protruding radially with respect to the die axis of rotation D, with which material is removed from the inner side 61 in order to produce the negative deformation, while the die rotates at a frequency f N Rotates around the female mold rotation axis D.

[0230] By superimposing an axial movement of the tool tip 71 along the die axis of rotation D with a radial movement about the die axis of rotation D, the tool tip 71 can be moved along the entire at least one inner side 61 .

[0231] The cutting tool tip 71 is rotated along the die rotation axis D at a cutting tool frequency f D Axial motion oscillation mode (such as in Figure 9 A negative track is turned into the die, which has a circumferential waviness in the circumferential direction, which corresponds to the negative impression of the desired trimming side deformation of the correction tool produced according to the die. N and turning tool frequency f D can be constant in time, but can also be varied in time. Analogously to the example explained above for direct machining of the trimming side by means of an adjusting tool, by corresponding superposition of the axial movement and radial movement of the turning tool tip 71 with respect to the die rotation axis D and by corresponding synchronization with the rotation of the die 60, a constant in time can be produced. Figures 2 to 6A All trim side modifications shown by way of example in FIG. 1 and their further variants.

[0232] Turning tool frequency f D and / or the rotation frequency f of the female mold N The axial and / or radial feed movement of the turning tool tip along the inner side 61 can be varied in time during machining in order to produce a targeted trimming side modification with a complex pattern.

[0233] Alternatively or additionally, the targeted generation of the negative deformation can also include the targeted generation of a clamping of the negative mold, as now according to Figure 10A and Figure 10B As explained.

[0234] Figure 10AA schematic cross-sectional view of the die 60 with the turning tool 70 is shown. In this embodiment, a deformation device 80 is positioned on the die 60 and clamps it. In the example shown here, the deformation device 80 applies a force to the die 60 in the axial direction about the die's axis of rotation D, causing it to be slightly compressed. This causes areas of the inner side 61 to be pressed closer together in the axial direction. If these areas of the inner side 61 that are pressed together now pass the fixed turning tool tip 71 during the die's rotation, greater material removal occurs in these areas that are pressed together than in other areas of the die 60 that are not compressed by the deformation device 80. Preferably, the deformation device 80 has force application areas periodically arranged in the circumferential direction of the die. To generate the force acting on these force application areas, the deformation device 80 can, for example, include mechanical or hydraulic clamping elements. In particular, the force can be applied directly to the force application areas via screws. Similarly, the force applied to the force application areas can be generated by hydraulic pistons. Alternatively or in addition, the deformation device can have a two-part device which at least partially surrounds the female mold and is held together by screws and / or hydraulic pistons. Figure 10B ), the negative mold then has a negative trajectory with circumferential waviness, wherein wave troughs appear in the negative mold at the locations where the forces act by the deformation device 80. These wave troughs in the negative mold 60 then correspond to wave peaks on the trimming side surface of the correction tool produced from the negative mold.

[0235] The use of the deformation device can of course also be combined with the use of a turning tool tip 71 that is moved relative to the die in order to produce any desired negative / trim-side deformations.

[0236] Dressing of grinding worms

[0237] The present invention also includes a method for dressing a grinding worm 16 for generating workpieces with prefabricated teeth, wherein the dressing profile of a dressing tool 33 is projected onto a grinding worm side 161 of the grinding worm, thereby generating a worm profile on the grinding worm side 161. The dressing tool 33 and the grinding worm side 161 are in line contact.

[0238] Figure 11 The projection of the grinding worm side 161 in the form of an unfolded circular ring in a plane perpendicular to the worm rotation axis B is shown, wherein the projection of the circular ring defines the worm circumferential coordinates The worm circumferential direction and the worm radial coordinate r S The radial direction of the worm.

[0239] On the unfolded grinding worm side 161, a worm modification in the form of three helical branches S1', S1", S1'" is schematically shown, wherein the three helical branches S1', S1", S1'" on the grinding worm side 161 correspond to the same helical branches S1 on the dressing side surface 331, but these same helical branches are transmitted to the grinding worm side 161 at different speed ratios between the dressing tool 33 and the grinding worm. Figure 11 The dashed arrows shown in the figure point in the direction of increasing speed ratio between the dressing tool 33 and the grinding worm: the greater the speed ratio, the steeper the reflected helical branches S1 ′, S1 ″, S1 ′″ extend on the developed grinding worm side 161. The worm profile generated by the transfer of the dressing side profile to the grinding worm side 161 has a certain number of wave periods per rotation of the grinding worm, which number is referred to here as the worm waviness order L. S By changing the speed ratio between the correction tool 33 and the grinding worm, the worm waviness order L can be influenced. S :The larger the speed ratio, the higher the worm waviness order L S Typically, the speed ratio is between 10 and 60.

[0240] The speed ratio can be constant over time or can be changed during the dressing of the grinding worm, wherein the mapped helical branch S1 ′ in this case no longer forms a straight line on the unfolded grinding worm side, but is formed in a curved manner (in the case of a sudden change in the speed ratio) or in an arc-shaped manner (in the case of a continuous change in the speed ratio).

[0241] Depending on the slope of the helical branch S1 on the dressing side surface 33 and the profile height d over which the helical branch S1 on the dressing side surface 33 extends, several revolutions of the correction tool are required in order to map the complete helical branch S1 onto the grinding worm side 161: the flatter the slope, the more revolutions are required.

[0242] Thus, a desired worm modification can be defined on the grinding worm side 161 of the screw thread of the grinding worm 16, which worm modification can be back-calculated to the corresponding dressing side modification for a fixed speed ratio selected between the correction tool 33 and the grinding worm, wherein the corresponding dressing side modification can then be produced in a targeted manner according to the manufacturing method described above.

[0243] Producing targeted side profiles on workpieces with pre-fabricated teeth

[0244] The worm profile produced by the dressing tool as explained above can be transferred to the tooth flanks of a workpiece with prefabricated teeth in a generating method.

[0245] Here, the generating method is performed on a generating grinding machine 1 which is Figure 12 , shown by way of example and hereinafter also referred to simply as "machine". The machine 1 has a machine base 11, on which a tool carrier 12 is guided movably in a radial feed direction X. The tool carrier 12 carries an axial slide 13, which is guided movably relative to the tool carrier 12 in a feed direction Z. A grinding head is mounted on the axial slide 13, which can be pivoted about a pivot axis (the so-called A-axis) extending parallel to the X direction in order to adapt the inclination angle of the tooth to be machined. The grinding head in turn carries a displacement slide 14, on which a tool spindle 15 can be moved relative to the grinding head in a displacement direction Y. A worm-shaped contoured grinding disc (grinding worm) 16 is clamped to the tool spindle 15. The grinding worm 16 is driven by the tool spindle 15 to rotate about the worm axis B.

[0246] The machine base 11 also carries a pivotable workpiece carrier 20 in the form of a turret, which can be pivoted between at least three positions about a pivot axis C3. Two identical workpiece spindles, diametrically opposed to one another, are mounted on the workpiece carrier 20, of which only one, 21, is visible in FIG1 . A workpiece can be clamped to each of the spindles and driven to rotate about the workpiece axis. The workpiece spindle 21, visible in FIG1 , can be driven about the workpiece axis C1 and is in a machining position, in which a workpiece 23 clamped thereto can be machined using a grinding worm 16 . Another workpiece spindle, offset by 180° and not visible in FIG1 , is in a workpiece exchange position, in which a finished workpiece can be removed from the spindle and a new blank can be clamped. A dressing device 30 is mounted offset by 90° relative to the workpiece spindles.

[0247] Therefore, the machine 1 has a plurality of movable components, such as slides or spindles, which can be moved in a controlled manner by corresponding drive devices. These drive devices are often referred to in the art as "NC axes," "machine axes," or simply "axes." This term sometimes also includes the components driven by the drive devices, such as slides or spindles.

[0248] The machine 1 also has a number of sensors. Figure 12For illustrative purposes, only two sensors 18 and 19 are schematically shown. Sensor 18 is a vibration sensor for detecting vibrations of the housing of the grinding spindle 15. Sensor 19 is a position sensor for detecting the position of the axial slide 13 relative to the tool carrier 12 in the Z direction. However, the machine 1 also includes a plurality of additional sensors. These sensors include, in particular, additional position sensors for detecting the actual position of each linear axis, rotational angle sensors for detecting the rotational position of each rotary axis, current consumers for detecting the drive current of each axis, and additional vibration sensors for detecting vibrations of each driven component.

[0249] All driven axes of machine 1 are digitally controlled via a machine control unit 40. Machine control unit 40 comprises a plurality of axis modules 41, a control computer 42, and a control panel 43. Control computer 42 receives operator commands from control panel 43 and sensor signals from various sensors of machine 1, and calculates control commands for axis modules 41 from these commands. Furthermore, the control computer outputs operating parameters to control panel 43 for display. Axis modules 41 provide control signals at their outputs for each machine axis.

[0250] A monitoring device 44 is connected to the control computer 42 and performs various monitoring tasks during the operation of the machine 1 .

[0251] exist Figure 13 1 is shown enlarged. The dressing device 30 is particularly clearly visible here. A dressing spindle 32 is pivotably arranged about a pivot axis C4 on a pivot drive 31, to which a disk-shaped dressing tool 33 is clamped, which has a specifically generated dressing-side profile.

[0252] In worm gearing, such as in a pair consisting of an externally toothed spur gear (pre-toothed workpiece 23) and a grinding worm, point contact occurs when the axes of the pre-toothed workpiece 23 and the grinding worm 16 are not parallel. During the development of the pair, the contact point moves along a path geometrically determined by the pair, on the tooth flanks of the pre-toothed workpiece 23 and on the grinding worm side 161 of the grinding worm 16. In this context, the path on the tooth flanks is referred to as the contact path, and the path on the grinding worm side is referred to as the worm contact path.

[0253] In one embodiment of the method for producing a modified surface structure on the tooth flank of a pre-toothed workpiece 23, the grinding worm 16 is first dressed according to the dressing method described above using a dressing tool 33, which has a helical waviness along the helical branch S1. The speed ratio between the dressing tool 33 and the grinding worm is selected such that the helical waviness is precisely mirrored along the worm contact path, which is predetermined by the pairing of the pre-toothed workpiece 23 to be machined and the grinding worm 16. In other words, the speed ratio is selected such that the helical branch S1', which is mirrored onto the grinding worm flank 161, lies on the worm contact path. The worm modification in the form of worm waviness along the helical branch S1' is now transferred in a targeted manner to the tooth flanks of the pre-toothed workpiece 23. To this end, the grinding worm 16 is driven to rotate about the worm axis B, while the pre-toothed workpiece 23 is driven to rotate about the workpiece axis C1, with the grinding worm and the pre-toothed workpiece now meshing. Furthermore, this now produces not only a movement of the grinding worm 16 relative to the pre-toothed workpiece 23 in a displacement direction Y parallel to the worm axis B, but also an axial movement of the grinding worm 16 parallel to the workpiece axis C1. The diagonal ratio of the grinding worm in the axial direction and in the displacement direction Y is selected so that the worm waviness is specifically mirrored onto the tooth flanks of the pre-toothed workpiece and, thereby, the surface structure of the tooth flanks is specifically modified.

[0254] Therefore, the desired tooth side modification can be defined on the tooth side of the workpiece 23 with prefabricated teeth, and for a selected diagonal ratio, the tooth side modification can be back-calculated to the corresponding worm waviness along the helical branch S1' on the grinding worm side 161, and the worm waviness can then be back-calculated to the corresponding dressing side modification for a selected speed ratio, wherein the corresponding dressing side modification can then be produced in a targeted manner according to the manufacturing method described above.

[0255] Reference Signs List

[0256] 1 Generating Grinding Machine

[0257] 11 base

[0258] 12 Tool carrier

[0259] 13 Axial slider

[0260] 14 Shift Slider

[0261] 15 Tool spindle

[0262] 16 Grinding worm

[0263] 161 Grinding worm side

[0264] 18 Acoustic Sensor

[0265] 19 Position Sensor

[0266] 20 Workpiece carrier

[0267] 21 Workpiece spindle

[0268] 211 Workpiece spindle drive device

[0269] 23 Workpiece

[0270] 30 Dressing device

[0271] 31 Pivot device

[0272] 32 Dressing spindle

[0273] 33 Correction tool

[0274] 330 matrix

[0275] 331 Trimming the side surface

[0276] 40 Machine control device

[0277] 41-axis module

[0278] 42 Control Computer

[0279] 43 Operation Panel

[0280] 44 Monitoring Device

[0281] 50 Adjusting equipment

[0282] 51 Adjust the tool

[0283] 511 Adjustment Rib

[0284] 52 Adjust the spindle

[0285] 53 Adjusting Controls

[0286] 60 female mold

[0287] 61 inside

[0288] 70 turning tool

[0289] 71 Turning tool tip

[0290] 80 deformation equipment

[0291] A. Trimming the rotation axis

[0292] B Worm axis

[0293] C1 workpiece axis

[0294] C3 pivot axis

[0295] C4 pivot axis

[0296] X feed direction

[0297] Y shift direction

[0298] Z feeding direction

[0299] K Adjust the rotation axis

[0300] D Female mold rotation axis

[0301] r radial coordinate

[0302] r' radial coordinate of the pattern rectangle

[0303] Angular coordinates

[0304] Worm circumferential coordinates

[0305] r S Worm radial coordinate

[0306] λ r' Radial wavelength

[0307] Offset Angle

[0308] α Tilt angle

[0309] d Profile height

[0310] r A inner radius

[0311] R1, R2 radial path

[0312] U1, U2 circular path

[0313] S1, S2, S3 spiral branches

Claims

1. A dressing tool for dressing a grinding worm (16) for generating a workpiece (23) with prefabricated teeth, The correction tool (33) is configured to rotate about a dressing rotation axis (A) and has a dressing side surface (331), wherein the dressing side surface forms a circular ring in a projection plane perpendicular to the dressing rotation axis (A), wherein the circular ring defines a radial direction with a radial coordinate (r) and an angular coordinate (r) circumferential direction, The trimming side surface (331) is provided with a targeted trimming side modification, wherein the trimming side modification can be described as being in relation to the radial coordinate (r) and the angular coordinate in a manner projected onto the ring. The related two-dimensional Fourier series, It is characterized by: The Fourier series is for the angular coordinates The circumferential frequency component that is not equal to zero has at least one Fourier coefficient that is not equal to zero.

2. The correction tool according to claim 1, wherein the trimming side modified portion is It has a 2π periodicity.

3. The correction tool according to claim 1 or 2, wherein for radial frequency components that are not equal to zero in the radial direction, the Fourier series does not have Fourier coefficients that are not equal to zero, so that the targeted trimming side modification is wavy with respect to the circumferential direction and has a wave front in the form of a line of constant phase, which is radially oriented in a manner projected onto the circular ring.

4. The correction tool according to claim 1, wherein the two-dimensional Fourier series has at least one Fourier coefficient that is not equal to zero for the radial frequency component and the circumferential frequency component that are not equal to zero, so that the trimming side modification portion forms a checkerboard-like structure having peaks and troughs that are staggered with each other in a checkerboard-like manner when projected onto the circular ring.

5. The dressing tool according to claim 4, wherein the checkerboard-like structure is oriented such that wave troughs and wave crests that are respectively adjacent in the circumferential direction are arranged along spiral branches (S1, S2, S3) that run spirally on the circular ring.

6. A method for producing a correction tool (33) according to any one of claims 1 to 5, the method comprising: A base body of the coating layer of the correction tool (33) is manufactured by a positive method, and The trimming side profile is produced in a targeted manner by means of an adjusting tool (51), in particular a rotating adjusting disk perpendicular to the trimming side surface.

7. The method according to claim 6, wherein the targeted generation of the trimmed side modification comprises: driving the correction tool (33) to rotate about the dressing rotation axis (A); driving the adjustment tool (51) to rotate about an adjustment rotation axis (K) of the adjustment tool (51), and The adjusting tool (51) is fed relative to the correcting tool (33) in a direction having a portion extending normal to the trimming side surface, so as to produce the trimming side modification by removing material from the trimming side surface (331).

8. A method for producing a correction tool (33) according to any one of claims 1 to 5, the method comprising: The correction tool (33) is manufactured by a negative method, wherein the negative method comprises: Manufacturing a female mold (60) by turning out a female matrix; A targeted female profile modification is turned into the turned female die (60) so that the female profile modification causes the trimming side modification, and / or During turning, the negative basic body is mechanically and / or hydraulically clamped, so that the turned negative die (60) has a negative profile after the mechanical clamping is released, which leads to the trimming side profile.

9. A method for dressing a grinding worm (16) for generating a workpiece with prefabricated teeth, the method comprising: The grinding worm (16) is dressed by means of a dressing tool (33) according to any one of claims 1 to 5, so that the dressing-side reshaping causes a worm reshaping on a grinding worm side (161) of the worm thread of the grinding worm (16).

10. The method according to claim 9, wherein a predetermined fixed rotational angle coupling exists between the correction tool (33) and the grinding worm (16) in order to selectively generate a periodic worm deformation along the worm thread on the grinding worm side (161).

11. The method according to claim 9, wherein a predetermined, temporally variable rotational angle coupling exists between the correction tool and the grinding worm (16) in order to generate a non-periodic worm modification on the grinding worm side (161) along the worm thread in a targeted manner.

12. A method for dressing a grinding worm (16) for generating a workpiece (23) with prefabricated teeth, the method comprising: defining a desired worm modification on a grinding worm side (161) of the worm thread of the grinding worm (16); For a selected fixed or variable rotational angle coupling between the correction tool (33) and the grinding worm (16), the desired worm profile is calculated back onto the corresponding dressing-side profile of the correction tool (33); The dressing tool (33) having the corresponding dressing side deformation is produced by means of a method according to any one of claims 6 to 8; The grinding worm (16) is dressed by means of the dressing tool (33) with a selected fixed or variable rotational angle coupling, wherein the dressing side profile produces the desired worm profile along the worm thread.

13. A method for producing a modified surface structure on the tooth flank of a workpiece (23) with prefabricated teeth, the method comprising: Dressing a grinding worm suitable for generating a workpiece (23) with prefabricated teeth by means of a method according to any one of claims 9 to 12; driving the grinding worm (16) to rotate about a worm axis (B); driving the workpiece (23) with prefabricated teeth to rotate around a workpiece axis (C1); Producing a relative movement between the grinding worm (16) and the pre-toothed workpiece (23) in a displacement direction (Y) parallel to the worm axis at a displacement feed speed, and generating a relative motion between the grinding worm and the workpiece with prefabricated teeth in an axial direction parallel to the workpiece axis (C1) at an axial feed speed, The grinding worm (16) and the workpiece (23) with pre-toothed teeth are in developing engagement, and the displacement feed speed and the axial feed speed are in a preset diagonal ratio, so that the worm modification is mapped onto the tooth side of the workpiece (23) with pre-toothed teeth, and the surface structure of the tooth side is modified in a targeted manner.

14. The method according to claim 13, wherein the correction tool is a correction tool (33) according to claim 5, and wherein during dressing there is a predetermined fixed rotational angle coupling between the correction tool (33) and the grinding worm (16), the rotational angle coupling being selected such that the helical branch (S1) is mapped onto the worm contact path, The worm contact path corresponds to the line along which the contact point between the grinding worm (16) and the pre-toothed workpiece (23) in generating engagement moves on the grinding worm side during the generating process.

15. An adjustment device, comprising: An adjustment tool (51) clamped on an adjustment spindle (52); a dressing spindle (32) configured to receive a dressing tool (33) for rotation about a dressing rotation axis (A); An adjustment control device (53) is configured to move the adjustment tool (51) relative to the correction tool (33) so that the correction tool (33) is provided with a trimming side profile according to any one of claims 1 to 5.

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