DE102023102805A1 - Method for grinding a gear - Google Patents

Abstract

The invention relates to a modified multi-cut profile grinding process for producing topological modifications to a gear tooth. For this purpose, the tooth flank (18) is segmented into flank sections (B1 - B5) and machined segment by segment with a grinding tool that is adapted to the topological modifications and has a flank clearance.

Description

The present invention relates to a method for grinding a gear.

The tooth flanks of gears are often modified. Gear modifications are used, for example, to improve load-bearing capacity, robustness against load- or tolerance-related displacements, or noise behavior, to name just a few aspects.

“Classic” gear modifications include, for example, recesses in the area of the tooth tip, the tooth root or the tooth ends, crowning in the profile and/or flank direction or angle modifications in the profile and/or flank direction. In order to achieve a desired flank shape, different profile and flank line modifications can be combined with one another by superposition.

As part of a software-based gear design, for example, an operator sets parameters for each of the desired modifications that determine the nature of the modification in question, with the flank shape being calculated based on these specifications. The options for designing the flank shape are limited by the calculation formulas stored in the software that are assigned to the respective modifications and that translate the entered parameters of the desired modifications into a target geometry of the tooth flank.

As an alternative to the superposition of the classic gear modifications, it is also known to define so-called topological modifications. Here, the tooth flank is viewed as a grid or free-form surface and modification values are freely specified based on support points on this grid. In this way, arbitrarily modified flank shapes can be defined that are not limited by a given catalog of predefined gear modifications. Against this background, the term "arbitrarily modified flank shapes" is of course limited to flank shapes that enable a functioning gear.

In gear technology, the geometry or flank shape that can actually be produced is closely linked to the manufacturing process used. Conventional profile grinding is currently the manufacturing process used for hard finishing of larger-module gears in the wind power sector. In profile grinding, the profile of the grinding wheel forms the negative of the tooth gap, so that one tooth flank or both tooth flanks can be ground in one overrun along the entire tooth height. This creates linear contact along the entire tooth height or along the entire rolling path.

Due to the linear contact between the grinding wheel and the tooth flank over the entire tooth height, profile grinding does not allow the creation of topological modifications. When designing gears for wind turbine gearboxes, however, there is a desire on the part of the market to be able to design the modifications to the tooth flanks more freely than is the case with the simple superposition of profile and flank line modifications, without losing sight of the economic efficiency of the grinding process.

In principle, methods suitable for producing topological modifications would be continuous generating grinding using a grinding worm, which is not established for larger modules, as well as the historical partial generating grinding.

In historical partial generating grinding, a rolling movement and pendulum strokes are superimposed on one another, using a grinding wheel with a trapezoidal profile. The removal area of the grinding wheel is limited to a point-shaped contact with the tooth flank. With today's CNC technology, it would be possible to specify a stroke path for each individual pendulum stroke that is optimized for the tooth flank modification specified in the contact area. However, due to the trapezoidal profile of the grinding wheel and the resulting point contact during grinding, this would require far too many cuts, which makes the process uneconomical.

One machining process that enables topological modifications is the so-called generation grinding from Kapp-Niles. In this process, a tooth flank is machined line by line in a final machining step using a special grinding wheel with a circular arc profile. There is therefore point contact between the grinding wheel and the tooth flank, resulting in extremely long machining times.

Another machining process that enables topological modifications is the so-called multi-cut grinding from Klingelnberg. Here, topological modifications are created by dividing finishing strokes into a few stroke cuts that only remove material in certain areas in the profile direction. The machining time is shorter than with the aforementioned generation grinding. However, the possibilities for topological modifications that can be created are significantly limited.

Against this background, the present invention is based on the technical problem of specifying a method for grinding a gear that enables the efficient grinding of gears with topological modifications.

The technical problem described above is solved with the features of the independent claim. Further embodiments of the invention emerge from the dependent claims and the description below.

According to the invention, a method is specified, comprising the method steps: grinding a tooth flank of a tooth of a gearing by means of a disk-shaped grinding tool, wherein two or more flank sections of the tooth flank are machined, wherein each of the flank sections is machined in a separate infeed, wherein each flank section is assigned machine settings that define a position of the grinding tool relative to the tooth, wherein for each of the machine settings, a line contact is formed between the grinding tool and the tooth flank, that a section of a profile of the grinding tool that is in cutting grinding contact with the tooth flank produces a shape of a target section of a target profile of the tooth flank on the flank section of the tooth flank assigned to the machine setting by carrying out a stroke movement in the tooth width direction and that a section of the profile of the grinding tool has a flank clearance to the tooth flank and is not in cutting grinding contact with the tooth flank, wherein at least one of the sections of the profile, which is in machining sliding contact with the tooth flank for at least one machine setting of the machine settings, has a flank clearance to the tooth flank for at least one further machine setting of the machine settings, wherein at least one of the sections of the profile which has a flank clearance to the tooth flank for at least one machine setting of the machine settings is in machining sliding contact with the tooth flank for at least one machine setting of the machine settings and wherein the target profile of the tooth flank, viewed along the tooth width, is not constant.

It can be provided that a shape of at least one section of the profile of the grinding tool, which is in cutting sliding contact with the tooth flank, corresponds to a shape of at least one desired section of the desired profile of the tooth flank and this shape of the desired section of the desired profile is mapped onto the flank section of the tooth flank assigned to the machine setting by carrying out a stroke movement in the tooth width direction.

Alternatively or additionally, it can be provided that a shape of at least one section of the profile of the grinding tool that is in cutting sliding contact with the tooth flank approximately corresponds to a shape of at least one target section of the target profile of the tooth flank and this shape of the target section of the target profile approximately maps onto the flank section of the tooth flank assigned to the machine setting by carrying out a lifting movement in the tooth width direction. In other words, such a section of the profile of the grinding tool can correspond to a distorted target profile of the tooth flank that enables the target profile of the tooth flank to be produced within the specified tolerance. When it is said here that the target profile of the tooth flank is not constant when viewed along the tooth width, this means in particular that the tooth flank has topological modifications.

According to the invention, the term "topological modifications" includes both classic modifications, such as recesses in the area of the tooth tip, the tooth root or the tooth ends, crowning in the profile and/or flank direction or also angle modifications in the profile and/or flank direction as well as a superposition of classic modifications. According to the invention, the term "topological modifications" also includes modifications in which the tooth flank is viewed as a grid or free-form surface and modification values are freely specified based on support points on this grid. In this way, arbitrarily modified flank shapes can be defined that are not restricted by a given catalog of predefined gear modifications. Against this background, the term "arbitrarily modified flank shapes" is restricted to flank shapes that enable a functioning gear.

For example, it may be useful to use the method according to the invention to make corrections to deviations that occur during the production of classic modifications. For example, a crowning of a helical gear can be created in three cuts by grinding in certain areas using the method according to the invention in order to minimize deviations.

The invention combines the efficiency of profile grinding with the flexibility of historical partial generating grinding. The method according to the invention can also be referred to as modified multi-cut profile grinding. This name is derived from an advantageous procedure for the process design of the method according to the invention. rens, which assumes an unmodified grinding wheel profile according to conventional profile grinding.

In conventional profile grinding, the grinding wheel profile forms the negative of the flank profile. In conventional profile grinding, there is therefore line contact between the grinding wheel profile and the tooth flank to be produced along the entire rolling path.

According to the invention, it can be provided that, in order to design the profile of the grinding tool, analogous to conventional profile grinding, this profile is initially defined as an unmodified profile which corresponds to the topologically modified target profile of the tooth flank in at least one section, e.g. in the face section. In this at least one section, the unmodified profile of the grinding tool therefore corresponds to the topologically modified target profile of the tooth flank - along the entire rolling path.

A flank section of the target geometry of the tooth flank can then be selected and machine settings, i.e. process kinematics, can be generated with which the specified topological modifications of the target profile of the tooth flank for this flank section along the tooth width can be generated in the best possible way with the unmodified profile of the grinding tool. The flank section can be defined, for example, as a rolling area.

Depending on the specified topological modification of the target profile of the tooth flank, the previously defined process kinematics may result in penetrations of the target profile of the tooth flank for flank sections adjacent to the selected flank section. In this case, the topological modifications of the target profile of the tooth flank cannot therefore be produced for the entire tooth flank with the unmodified profile of the grinding tool.

In order to avoid the penetrations, the unmodified profile of the grinding tool is modified by defining the flank clearance and thus specifying a modified profile of the grinding tool. Essentially, the modification of the grinding tool consists in the unmodified profile of the grinding tool being reduced in one or more areas adjacent to the section of the profile of the grinding tool that grinds the selected flank section in order to avoid the aforementioned penetrations.

Subsequently, machine settings, i.e. a respective process kinematics, are defined for the production of the further flank sections of the tooth flank in order to generate the topologically modified target geometry of the entire tooth flank or the topologically modified target profile of the tooth flank along the entire tooth width with the modified grinding tool.

In other words, the topologically modified target profile of the tooth flank is segmented and ground with associated segments of the profile of the modified grinding tool.

The proposed modified multi-cut profile grinding therefore enables the efficient production of topological modifications.

In the above example, the profile of the grinding tool is designed from the face cut. However, the starting point for the design can also be any other monotonous line on the tooth flank in the rolling path that covers the entire area from a root form circle to a tip circle. Examples of possible options here are a contact line between the grinding wheel and the tooth flank at a specified stroke position, but also lines that characterize the shape of the specified topological modification, such as height or crest lines. When designing the grinding wheel profile for contact with the target flank along a line with the smallest deviations, it can be ensured that the first cut produces no or only minimal penetrations and that flank clearance is already present at least in sections, without additional area-specific modifications to the wheel profile.

The profile of the grinding tool, which has a flank clearance to the target profile of the tooth flank, can also be referred to as the modified profile of the grinding tool. The grinding tool with the modified profile can be referred to as a modified grinding tool.

The number of cuts or the number of flank sections can be determined depending on the specified topological modifications.

For example, it may be provided that the tooth flank is divided into three or more flank sections.

For example, it may be provided that the tooth flank is divided into ten or fewer flank sections.

For example, it can be provided that the tooth flank is divided into exactly three or exactly four or exactly five or exactly six flank sections.

When we speak here of machine settings assigned to a flank section, these machine settings contain in particular a process kinematics for the complete machining of the flank section in question along the tooth width with the assigned section of the profile of the grinding tool.

According to one embodiment of the method, it can be provided that a flank line and/or profile line of the tooth flank running along the tooth width is at least partially undulating. Undulating means in particular that a flank line and/or a profile line of the tooth flank describes a curve with one or more turning points compared to an unmodified flank line and/or profile line.

Alternatively or additionally, the target profile of the tooth flank can be involute-shaped at least in sections. In particular, the target profile of the tooth flank can be involute-shaped in the load-bearing areas of the tooth flank, i.e. in those areas that roll or mesh with an associated tooth flank of another gear during operation for power transmission.

According to a further embodiment of the method, the profile of the grinding tool can be non-trapezoidal. In contrast to historical partial generating grinding, the profile of the grinding tool - namely the modified profile of the grinding tool for which the flank clearance is taken into account - is adapted at least in sections to the topologically modified target profile of the tooth flank. In combination with the machine kinematics adapted to this, the number of cuts required can be significantly reduced compared to historical partial generating grinding, since line contact is enabled for the relevant flank section instead of point contact.

In particular, it can be provided that the profile of the grinding tool is convexly curved in at least one of the sections that carries out machining of a load-bearing region of the tooth flank. As already mentioned, such a load-bearing region of the tooth flank is the region that is involved in the load transfer during operation of the gear and is in rolling contact with a correspondingly assigned further gear.

It can be provided that a target profile of the grinding tool is the same for all machine settings. It goes without saying that the actual profile of the grinding tool is not exactly identical from cut to cut due to signs of wear. For this reason, the term target profile of the grinding tool is introduced here to emphasize that the same profile geometry of the grinding tool is used for each machine setting and that the grinding tool is not dressed to a different profile geometry between the individual cuts. It can, however, be provided that between two cuts for machining successive flank sections or after machining a tooth flank and before machining another tooth flank, the grinding tool is dressed to the specified target profile, which reflects the profile of the grinding tool according to the invention including the intended flank clearance.

Accordingly, the topological modifications of the tooth flank can be created with one and the same profile geometry of the grinding tool for all flank sections. A gear can therefore be ground with topological modifications, whereby one and the same profile geometry of the grinding tool can be used to machine the entire tooth flank.

According to alternative embodiments of the method, it can be provided that the flank clearance, viewed for a machine setting, grows starting from the section of the cutting sliding contact along the rolling path. In this way, it can be ensured that even in sections of the profile of the grinding wheel that are further away from the section of the cutting sliding contact, no unwanted penetration of the topologically modified target geometry or the topologically modified target profile of the tooth flank occurs for further machine settings. In particular, it can be provided that the flank clearance, viewed for a machine setting, grows linearly starting from the section of the cutting sliding contact along the rolling path.

Alternatively, it can be provided that a flank clearance and a profile shape of the target profile are calculated based on a predefined rolling position and an associated process kinematics.

According to a further embodiment of the method, it can be provided that a single-sided and individual grinding process is carried out, whereby the grinding tool is in grinding contact exclusively with the tooth flank to be machined and during grinding of the tooth flank to be machined, there is no grinding contact with any other tooth flank. Left flanks and right flanks are therefore manufactured independently of each other in separate infeeds.

In the present case, the grinding tool is in particular not a worm-shaped grinding tool, such as a grinding worm or the like, but a grinding wheel which is intended for the successive, individual machining of the tooth flanks, gap by gap.

According to one embodiment of the method, it can be provided that before grinding the flank sections, at least one grinding operation of the tooth flank takes place by profile grinding, wherein the tooth flank is ground in particular over the entire width and along the entire rolling path and wherein in particular an allowance is kept for the subsequent machining of the flank sections. Accordingly, in particular a conventional profile grinding can be carried out first before topological modifications are carried out by means of the multi-cut machining of the tooth flank in the form of the division into flank sections according to the invention. An allowance kept for the final grinding of the flank sections can in particular be selected in such a way that deviations resulting from the preceding overruns in conventional profile grinding can be equalized.

It can be provided that each of the flank sections is machined in two or more passes. This means that as an alternative or in addition to the conventional profile grinding described above, which can be carried out before the machining of the flank sections, the machining of the flank sections can also be carried out in several passes.

According to one embodiment of the method, it can be provided that at least two of the flank sections overlap at least in sections. In this way, a high quality of the mapping of the required modifications onto the tooth flank can be achieved.

It can be provided that a required flank clearance is calculated for all machine settings and a maximum of the required flank clearance is defined as the flank clearance. In this way, it can be reliably avoided that for one of the machine settings during the production of one of the flank sections, penetrations of the target profile of adjacent flank sections occur.

According to one embodiment of the method, it can be provided that the target profile of the tooth flank, which is not constant when viewed along the tooth width, has a topological modification, wherein the respective machine setting assigned to a flank section contains machine kinematics for generating the topological modification and wherein the topological modification is mapped by means of two machine axes.

The computer-aided generation of the required machine kinematics for producing the topological modification is an optimization problem. By only releasing two machine axes for solving this optimization problem, the degrees of freedom for optimization are restricted in order to simplify the finding of a global minimum in the solution space. For example, it can be provided that a shift axis and a workpiece rotation axis of a machine tool for gear manufacturing are released for optimization. These axes thus serve as correction axes to enable the required topology of the tooth flanks to be achieved during the production of the flank sections.

Alternatively or additionally, it can be provided that a linear axis for radial feed and/or a swivel axis of the grinding tool are released as additional or alternative degrees of freedom for determining the machine kinematics.

The selection and number of axes released for optimization can depend on the shape and nature of the topological modification.

It can be provided that a shape of the flank sections has a constant starting rolling path and an end rolling path, viewed over the width of the tooth flank, and that the flank sections are substantially rectangular.

Alternatively, it can be provided that a shape of the flank sections has a non-constant starting rolling path and final rolling path, viewed across the width of the tooth flank, and that the flank sections are substantially trapezoidal, diamond-shaped or triangular.

Alternatively, it can be provided that the flank sections are not parallel to the tooth width, but extend at an angle over the tooth flank.

• 1A das Profilschleifen gemäß dem Stand der Technik;
• 1B ein schrägverzahntes Stirnrad;
• 1C eine topologisch modifizierte Zahnflanke und eine nicht modifizierte Zahnflanke;
• 2 ein unmodifiziertes Profil einer Schleifscheibe;
• 3 das unmodifizierte Profil einer Schleifscheibe aus 2 überlagert mit einem modifizierten Profil der Schleifscheibe;
• 4 das modifizierte Profil der Schleifscheibe aus 3
• 5 ein Flankenspiel für einen dritten Flankenabschnitt bezogen auf eine unmodifizierte Zahnflanke;
• 6 ein Flankenspiel für den dritten Flankenabschnitt für zugeordnete Maschineneinstellungen bezogen auf die topologisch modifizierte Zahnflanke gemäß 1C;
• 7 ein Flankenspiel für einen ersten Flankenabschnitt bezogen auf eine unmodifizierte Zahnflanke;
• 8 ein Flankenspiel für den ersten Flankenabschnitt für zugeordnete Maschineneinstellungen bezogen auf die topologisch modifizierte Zahnflanke gemäß 1C;
• 9 ein Flankenspiel für einen fünften Flankenabschnitt bezogen auf eine unmodifizierte Zahnflanke;
• 10 ein Flankenspiel für den fünften Flankenabschnitt für zugeordnete Maschineneinstellungen bezogen auf die topologisch modifizierte Zahnflanke gemäß 1C;
• 11 die topologisch modifizierte Zahnflanke aus 1 mit dem zugeordneten Flankenspiel gemäß der beschriebenen Schleifwerkzeug- und Prozessauslegung;
• 12 Verfahrensschritte des erfindungsgemäßen Verfahrens.

The invention is described in more detail below with reference to a drawing showing exemplary embodiments. The drawings show schematically:

• 1A profile grinding according to the state of the art;
• 1B a helical gear;
• 1C a topologically modified tooth flank and a non-modified tooth flank;
• 2 an unmodified profile of a grinding wheel;
• 3 the unmodified profile of a grinding wheel made of 2 superimposed with a modified profile of the grinding wheel;
• 4 the modified profile of the grinding wheel 3
• 5 a flank clearance for a third flank section relative to an unmodified tooth flank;
• 6 a flank clearance for the third flank section for assigned machine settings related to the topologically modified tooth flank according to 1C ;
• 7 a flank clearance for a first flank section relative to an unmodified tooth flank;
• 8th a flank clearance for the first flank section for assigned machine settings related to the topologically modified tooth flank according to 1C ;
• 9 a flank clearance for a fifth flank section relative to an unmodified tooth flank;
• 10 a flank clearance for the fifth flank section for assigned machine settings related to the topologically modified tooth flank according to 1C ;
• 11 the topologically modified tooth flank 1 with the associated flank clearance according to the described grinding tool and process design;
• 12 Process steps of the process according to the invention.

1A shows grinding of a straight-toothed spur gear 2 using a grinding wheel 4 according to the prior art. This is profile grinding. A profile 6 of the grinding wheel 4 essentially corresponds to the shape of a gap 8 of the spur gear 2. Right-hand flanks and left-hand flanks are machined simultaneously. In other words, the profile 6 of the grinding wheel 4 is essentially the negative of the gap 8.

1 B shows a helical spur gear 10. A tooth flank 12 of the helical spur gear 10 is shown by way of example by grid lines 14 which extend along a tooth width B and along a tooth height H. The shape of a tooth flank can be freely represented or defined using such a grid 14 as part of a gear design, as will be shown below using 1C explained.

Right in the picture of 1C a topology of an unmodified tooth flank 16 is shown as an example, with a tooth width extending from 0 - 150 mm and with topological modifications over a rolling path of 18 - 32 mm for the involute tooth flank 16 being shown - with the modification for the flank 16 shown on the right in the picture being zero in this case, since no modification is present. The target profile of the tooth flank 16 shown on the right in the picture is constant when viewed along the tooth width.

Left in the picture of 1C a topologically modified, involute tooth flank 18 is shown as an example, whereby the tooth flank 18 has wave-shaped modifications. Here too, a tooth width of 0 - 150 mm extends and the topological modifications are plotted over a rolling path of 18 - 32 mm. As can be seen from the scaling of the height profile, the extent of the modifications is less than 0.01 mm.

For the tooth flank 18, both wave-shaped flank lines 20 running along the tooth width and wave-shaped profile lines 22 running along the rolling path in the tooth height direction can be seen. It is clear that a tooth flank 18 topologically modified in this way cannot be compared with the 1A shown profile grinding can be produced.

One way to produce the topologically modified tooth flank 18 is to traverse the specified, topologically modified target profile line by line in point contact. However, such a procedure is very time-consuming and inefficient.

According to the invention, the tooth flank 18 is divided along the rolling path into five flank sections B1 to B5 (see 1C ). This division is based on an unmodified profile 24 of a disc-shaped grinding tool 26 (see 2 ). The axial width of the grinding tool 26 is plotted on the horizontal axis, while the diameter in the radial direction is plotted on the vertical axis - each in millimeters.

The design of the grinding process begins in a first step by specifying the unmodified profile 24 in such a way that it is in at least one face section of the topologically modified fied tooth flank 18. Based on this, machine settings are calculated with which the flank section B3 can be produced over the entire tooth width. Due to the wave-shaped modified topology of the tooth flank 18, however, this results in the adjacent flank sections B1, B2, B4, B5 ( 1C ) to penetrations of the 1C specified target profile of the tooth flank 18.

In order to avoid these penetrations, the unmodified profile 24 of the disc-shaped grinding tool 26 is modified by providing the unmodified profile 24 with a flank clearance in order to 3 and 4 shown modified profile 28 of the disc-shaped grinding tool 26. In the 2 , 3 and 4 the reference symbols B1 to B5 are also indicated to show with which sections S1 - S5 of the grinding wheel profile the respectively assigned flank sections B1 to B5 are manufactured.

As in 3 As can be seen, the modified profile 28 of the grinding tool 26 has been reduced in those sections S1, S2, S4, S5 which are intended for the production of the flank sections B1, B2, B4, B5 in order to ensure a flank clearance during the production of the flank section B3 by means of the associated area S3 of the grinding tool 26. The flank clearance which is achieved by the modified geometry or the modified profile 28 of the disk-shaped grinding tool 26 therefore enables the flank section B3 to be produced without penetrations of the target profile of the modified topology of the tooth flank 18 occurring in the adjacent flank sections B1, B2, B4, B5.

5 shows an example of a flank clearance 30 of the modified profile 28 for the case of an unmodified tooth flank. Instead of the rolling path, the diameter of 148 - 156 mm in the area of the tooth flank is plotted over the tooth width of 0 mm - approx. 50 mm.

6 shows a flank clearance 32 of the modified profile 28 during the production of the flank section B3 of the topologically modified tooth flank 18 with the machine settings assigned to the flank section B3. Instead of the rolling path, the diameter of 148 - 156 mm in the area of the tooth flank is plotted over the tooth width of 0 mm - approx. 150 mm. How 6 As can be seen, the flank section B3 can be mapped along the tooth width by means of the modified profile 28, while no sliding contact takes place due to the flank clearance in adjacent areas.

The 7 and 8th relate to the production of the flank section B1 of the topologically modified tooth flank 18 by means of the modified profile 28 of the grinding wheel 26 and show a flank clearance 34 for a non-topologically modified target profile and a flank clearance 36 during the production of the flank section B1 of the topologically modified tooth flank 18 with the machine settings assigned to the flank section B1.

The 9 and 10 relate to the production of the flank section B5 of the topologically modified tooth flank 18 by means of the modified profile 28 of the grinding wheel 26 and show a flank clearance 38 for a non-topologically modified target profile and a flank clearance 40 during the production of the flank section B5 of the topologically modified tooth flank 18 with the machine settings assigned to the flank section B5.

The production of the flank sections B2 and B4 is carried out analogously and is not shown in detail.

The modified profile 28 of the grinding wheel 26 remains unchanged for the production of all flank sections B1 to B5. This means that once the required flank clearance has been determined, the flank sections B1 to B5 to be produced are all manufactured with the same grinding wheel geometry.

11 shows in a summary representation the distribution of the flank sections B1, B2 and B3 into the three exemplary sections with the associated flank clearance. The sections are each stroke cuts along the entire tooth width.

According to the invention, a method is therefore provided, comprising the method steps: grinding a tooth flank 18 of a tooth of a gearing 10 by means of a disk-shaped grinding tool 26, wherein five flank sections B1 - B5 of the tooth flank 18 are machined.

Each of the flank sections B1 - B5 is machined in a separate infeed, wherein each flank section B1 - B5 is assigned machine settings which define a position of the grinding tool 26 relative to the tooth or to the tooth flank 18.

For each of the machine settings, a line contact is formed between the grinding tool 26 and the tooth flank 18.

For each of the machine settings, a shape of a section S1 - S5 of the profile 28 of the grinding tool 26, which is in contact with the tooth flank 18 is in the cutting sliding contact, corresponds to a shape of a target section of a target profile of the tooth flank 18 and maps this shape of the target section of the target profile onto the flank section B1 - B5 of the tooth flank 18 assigned to the machine setting by executing a lifting movement in the tooth width direction.

For each of the machine settings, a section S1 - S5 of the profile 28 of the grinding tool 26 has a flank clearance to the tooth flank and is not in cutting grinding contact with the tooth flank.

Furthermore, at least one of the sections of the profile which is in machining sliding contact with the tooth flank for at least one machine setting of the machine settings has a flank clearance 32, 36, 40 with the tooth flank 18 for at least one further machine setting of the machine settings, and that at least one of the sections S1 - S5 of the profile 28 which has a flank clearance 32, 36, 40 with the tooth flank 18 for at least one machine setting of the machine settings is in machining sliding contact with the tooth flank 18 for at least one machine setting of the machine settings.

The involute nominal profile of the tooth flank 18 is not constant when viewed along the tooth width - in this case it is modified in a wave-like manner.

The profile 28 of the grinding tool 26 is not trapezoidal and is convexly curved in the sections S1 - S5, which carry out machining of a supporting region of the tooth flank 18.

As can be seen from the figures, the flank clearance, considered for a machine setting, increases starting from the section of the cutting sliding contact along the rolling path.

A method can be specified, wherein first in a method step (A) a conventional profile grinding is carried out and wherein in a method step (B) the described modified multi-cut profile grinding according to the invention is carried out.

The above statements are to be understood as examples. According to alternative embodiments, it can be provided that a shape of at least one section S1 - S5 of the profile 28 of the grinding tool 26, which is in cutting sliding contact with the tooth flank 18, approximately corresponds to a shape of at least one desired section of the desired profile of the tooth flank 18 and this shape of the desired section of the desired profile approximately maps onto the flank section B1 - B5 of the tooth flank 18 assigned to the machine setting by carrying out a lifting movement in the tooth width direction.

Reference symbol

2

Spur gear

4

Grinding wheel

6

profile

8th

gap

10

helical gear

12

Tooth flank

14

Grid

16

unmodified tooth flank

18

topologically modified tooth flank

20

flank line

22

Profile line

24

unmodified grinding wheel profile

26

Grinding wheel

28

modified grinding wheel profile with flank clearance

30

Cross play

32

Cross play

34

Cross play

36

Cross play

38

Cross play

40

Cross play

B1-B5

Flank sections

S1-S5

Sections of the grinding wheel profile

B

Tooth width direction

H

Tooth height direction

(A)

Process step

(B)

Process step

Claims (12)

Method, comprising the method steps: - grinding a tooth flank (18) of a tooth of a gearing (10) by means of a disk-shaped grinding tool (26), - wherein two or more flank sections (B1 - B5) of the tooth flank (18) are machined, - wherein each of the flank sections (B1 - B5) is machined in a separate infeed, - wherein each flank section (B1 - B5) is assigned machine settings which determine a position of the grinding tool (26) relative to the tooth define, - wherein for each of the machine settings, - a line contact is formed between the grinding tool (26) and the tooth flank (18), - that a section (S1 - S5) of a profile (28) of the grinding tool (26) which is in cutting sliding contact with the tooth flank (18) produces a shape of a desired section of a desired profile of the tooth flank (18) on the flank section (B1 - B5) of the tooth flank (18) associated with the machine setting by carrying out a lifting movement in the tooth width direction and - that a section (S1 - S5) of the profile (28) of the grinding tool (26) has a flank clearance (32, 36, 40) to the tooth flank (18) and is not in cutting sliding contact with the tooth flank (18), - wherein at least one of the sections (S1 - S5) of the profile (28) of the Grinding tool (26) which is in machining sliding contact with the tooth flank (18) for at least one machine setting of the machine settings, has a flank clearance (32, 36, 40) with the tooth flank (18) for at least one further machine setting of the machine settings, - wherein at least one of the sections (S1 - S5) of the profile (28), which has a flank clearance (32, 36, 40) with the tooth flank (18) for at least one machine setting of the machine settings, is in machining sliding contact with the tooth flank (18) for at least one machine setting of the machine settings and - wherein the target profile of the tooth flank (18), viewed along the tooth width, is not constant. Procedure according to Claim 1 , characterized in that - that a shape of at least one section (S1 - S5) of the profile (28) of the grinding tool (26) which is in cutting sliding contact with the tooth flank (18) corresponds approximately to a shape of at least one desired section of the desired profile of the tooth flank (18) and this shape of the desired section of the desired profile is mapped onto the flank section (B1 - B5) of the tooth flank (18) assigned to the machine setting by carrying out a lifting movement in the tooth width direction and/or - that a shape of at least one section (S1 - S5) of the profile (28) of the grinding tool (26) which is in cutting sliding contact with the tooth flank (18) corresponds approximately to a shape of at least one desired section of the desired profile of the tooth flank (18) and this shape of the desired section of the desired profile is mapped onto the flank section (B1 - B5) of the tooth flank (18) assigned to the machine setting Flank section (B1 - B5) of the tooth flank (18) by executing a lifting movement in the tooth width direction. Procedure according to Claim 1 or Claim 2 , characterized in that a flank line (20) of the tooth flank running along the tooth width and/or a profile line (22) running in the tooth height direction is at least partially wave-shaped and/or the desired profile of the tooth flank (18) is at least partially involute-shaped. Method according to one of the preceding claims, characterized in that the profile (28) of the grinding tool (26) is not trapezoidal and/or the profile (28) of the grinding tool (26) is convexly curved in at least one of those sections (S1 - S5) which carries out machining of a supporting region of the tooth flank (18). Method according to one of the preceding claims, characterized in that a desired profile (28) of the grinding tool (26) is the same for all machine settings. Method according to one of the preceding claims, characterized in that the flank clearance (32, 36, 40), considered for a machine setting, grows linearly starting from the section (S1 - S5) of the cutting sliding contact along the rolling path. Method according to one of the preceding claims, characterized in that a single-sided, individual-part grinding operation is carried out, wherein the grinding tool (26) is in grinding contact exclusively with the tooth flank (18) to be machined and is not in grinding contact with any other tooth flank during the grinding of the tooth flank (18) to be machined. Method according to one of the preceding claims, characterized in that before grinding the flank sections (B1 - B5), at least one grinding of the tooth flank (18) is carried out by profile grinding, wherein the tooth flank (18) is ground in particular over the entire width and along the entire rolling path and wherein in particular an allowance is kept for the subsequent machining of the flank sections (B1 - B5) and/or that each of the flank sections (B1 - B5) is machined in two or more passes. Method according to one of the preceding claims, characterized in that at least two of the flank sections overlap at least in sections. Method according to one of the preceding claims, characterized in that a required flank clearance is calculated for all machine settings and a maximum of the required flank clearance is defined as the flank clearance. Method according to one of the preceding claims, characterized in that the desired profile of the tooth flank (18), which is not constant when viewed along the tooth width, has a topological modification, wherein the respective machine setting assigned to a flank section (B1 - B5) contains machine kinematics for generating the topological modification and wherein the topological modification is mapped by means of two machine axes. Method according to one of the preceding claims, characterized in that - a shape of the flank sections (B1 - B5) has a constant starting rolling path and a final rolling path, viewed across the width of the tooth flank, and the flank sections are substantially rectangular, or - a shape of the flank sections has a non-constant starting rolling path and a final rolling path, viewed across the width of the tooth flank, and the flank sections are substantially trapezoidal, diamond-shaped or triangular, or - the flank sections do not extend parallel to the tooth width but at an angle across the tooth flank.

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