WO2021180633A1

WO2021180633A1 - Method for hob-machining a gear wheel

Info

Publication number: WO2021180633A1
Application number: PCT/EP2021/055751
Authority: WO
Inventors: Peter Kopton; Gábor SZALAI; Markus Heilmann
Original assignee: Audi Ag; AUDI HUNGARIA Zrt.
Priority date: 2020-03-13
Filing date: 2021-03-08
Publication date: 2021-09-16
Also published as: DE102020106910A1

Abstract

The invention relates to a method for hob-machining, in particular hobbing or hob-grinding, a gear wheel (1) with any type of toothing, for instance spur toothing or helical toothing or the like, by means of a hobbing worm (9) that is driven, during hob-machining, in a hobbing direction of rotation (D) about a hobbing-worm axis (B), wherein the hobbing worm (9) is in cutting engagement with the gear wheel (1) corotating about a gear-wheel axis (C), specifically at a contact point (K) between a hobbing-worm flank and a gear-wheel tooth flank, wherein the contact point (K) is shifted along the gear-wheel axis (C) in an advancing movement (fz) across a tooth width (b) of the gear wheel (1), and wherein, in the hob-machining process, the hobbing worm (9) is controlled such that, in every machining plane (E1, E2, ...) at right angles to the gear-wheel axial direction (C), all respective gear-wheel teeth have a constant modulus (m). During the hob-machining process, the hobbing worm (9) and/or the gear wheel (1) execute(s) an axial movement (∆s, R, S), by means of which the modulus (m) at least partially changes across the tooth width (b).

Description

Process for generating a gear

DESCRIPTION:

The invention relates to a method for hobbing, in particular for hobbing and / or for grinding a gear according to the preamble of claim 1.

The toothing of gears can be produced by continuous generating grinding or by continuous hobbing. Continuous generating grinding is a method for hard finishing of tooth flanks, while continuous hobbing is a method for soft finishing of tooth flanks. A generating grinding worm or a hobbing worm, which has a cylindrical base body with at least one helically extending worm thread, is used as the tool. The kinematics of hobbing and hob grinding is similar to a helical gear unit.

A toothed wheel produced by generating grinding or by hobbing can have a toothing which, compared to a standardized toothing, is modified in such a way that tolerances, such as position errors of the axes, are taken into account. In addition, the tooth flanks can optionally be provided with a crown in order to reduce noise development during operation and to improve the vibration behavior, the strength, the distribution of forces and the surface pressure of the teeth. In a special embodiment variant, the module of the gear wheel can vary over the tooth width in a gear wheel axial direction. The module indicates the size of the gear. Only gears with the same module can be paired with one another. The module (i.e. the diameter division) of a gear is a basic dimension or a reference variable to which all other gear parameters (tooth tip height, tooth root height, tooth height, circumferential pitch).

From DE 10 2015 209 917 A1 a generic method and a machine tool for machining gears by milling and / or grinding are known. During the generating process, a generating worm is driven in a generating direction of rotation about a generating worm axis and in a gear-worm-like cutting engagement with the gearwheel rotating about a gear axis. The cutting engagement takes place at a contact point between a pitch worm flank and a gear tooth flank. In the rolling machining process, the rolling worm is adjusted in a feed movement along the gear axis. Coupled with the motion of the worm feed motion, the contact point is shifted along the gear axis. The rolling machining process is controlled in DE 10 2015 209 917 A1 in such a way that the gearwheel has a module that is constant over the tooth width.

From DE 101 04 410 A1 a grinding worm for generating grinding of gears is known. A hob cutter is known from DE 2 212 225 A. From DE 20 2014 104 881 U1 a grinding machine with a grinding tool for simultaneous generating grinding of two workpieces is known. From DE 44 03 236 A1 a grinding worm for generating grinding of cylindrical spur gears is known.

The object of the invention is to provide a method for rolling machining with which, compared to the prior art, a gearwheel with a module that varies over the tooth width can be produced in a simpler manner.

The object is achieved by the features of claim 1. Preferred developments of the invention are disclosed in the subclaims. The invention is based on a rolling machining process in which all gear teeth are produced with a constant module in a machining plane at right angles to the gear wheel axial direction and in which the rolling worm is adjusted with a feed movement along the gear wheel axis to relocate motion-coupled contact point along the gear axis. According to the characterizing part of claim 1, in addition to the feed movement, a further roller screw axis movement is impressed on the roller screw in the roller machining process. By means of the further roller worm axis movement, it can be achieved that the module changes at least partially over the tooth width in the gear wheel axial direction. By controlling the rolling worm axis movement, a material removal at the contact point changes on the gear tooth flank and thus also the module generated locally there.

In a technical implementation, the rolling worm can be adjusted in the rolling machining process in a feed movement along the gear axis in different feed positions. Each feed position is assigned a machining plane at right angles to the gearwheel axial direction, in which a module that is constant in the circumferential direction of the gearwheel (i.e. in the machining plane) is generated at the contact point with material removal.

For perfect gear meshing, it is important that the module generated is constant in every machining plane (at right angles to the gear axis). It is therefore preferred if the pitch worm remains in each feed position until at least one complete gear wheel revolution has taken place. This ensures that all teeth of the gear are machined at the contact point, forming a constant module.

In one embodiment variant, the rolling machining process can be controlled in such a way that the module generated in a first feed position differs from a module generated in a second feed position differs. For such a module change, the further roller screw axis movement can be impressed on the roller screw feed movement.

In current practice, the rolling worm can have at least one worm thread which runs helically around a rolling worm base body. In a first embodiment, the pitch worm can be conical. In this way, an active roller screw outer diameter at the contact point can be continuously reduced from a large diameter roller screw end face to an axially opposite small diameter roller screw end face. For a module change in the axial direction of the gearwheel, the process control can therefore adjust the conical worm gear by a travel in the worm gear axis. This changes the active pitch worm diameter at the contact point and, accordingly, also the material removal at the contact point, namely with a change in the module.

In a second embodiment of the invention, the further roller screw axis movement can be a pivoting movement of the roller screw about a pivot axis, in which the roller screw can be adjusted by a pivot angle during the roller machining, and / or a roller screw radial movement axially parallel to the roller screw axis around which to generate a module that varies over the tooth width of the gearwheel. In a preferred variant, the pivot axis can be aligned axially parallel to the gear wheel axis.

During the hobbing in the gear cutting machine, the worm can be adjusted in a feed direction parallel to the gear axis by means of a tool feed. In addition, the roller worm can be adjusted via a shift movement along its roller screw axis of rotation in order to extend its service life. The additional further axis movement is called the rolling rotation movement, the Rolling worm feed and the shifting movement of the rolling worm are superimposed.

Another aspect of the invention relates specifically to the production of a gearwheel, which in the finished state has at least a first

Having gear section with a first module area and a second gear section with a second module area. To produce the gearwheel, a multi-start roller worm can be used, which has at least two helical worm threads running around a main body of the pitch circle. According to the invention, the first

The worm thread and the second worm thread can each be designed with mutually different worm thread profiles. During the hobbing process, the first module area in particular can be generated with the aid of the first worm gear. In contrast, the second module area of the gearwheel can specifically be produced by means of the second worm gear.

The rolling machining according to the invention can be part of a fully automated process chain for manufacturing the gear. The process chain can have further conventional hobbing and / or generating grinding process steps in any way.

The method according to the invention can be used specifically in the production of a gearwheel in which the following polynomial equation applies to the pitch circle diameter, which is directly proportional to the module: do (b) = ao + ai b + a2 b ² + a3 b ³ + ... + a _n b ⁿ , where ao, ai, a2, a3, a _{n are} constants.

In hobbing, the worm gear can be controlled on the basis of this polynomial equation.

Exemplary embodiments of the invention are described below with reference to the accompanying figures.

Show it: 1 and 2 each show views of a toothed wheel with a module varying at least partially over the tooth width; 3 shows a basic illustration of generating grinding machining according to the invention;

FIGS. 3a and 3b each show views by means of which a rolling machining process is illustrated;

4 and 5 are views of a generating grinding worm according to the invention;

FIG. 6 shows a second exemplary embodiment of the invention in a view corresponding to FIG. 3;

FIG. 7 shows, in a view corresponding to FIG. 4, a hobbing worm for hobbing;

FIG. 8 shows, in a view corresponding to FIG. 3, a generating grinding process known from the prior art;

Figures 9 to 12 views according to an alternative embodiment; and FIG. 13 shows a further exemplary embodiment.

1 or 2, a gear 1 with straight teeth is shown, which is produced with the aid of the method according to the invention. In the gear wheel axial direction, the gear wheel 1 has a central gear wheel axial section 3, to which lateral gear wheel axial sections 5 adjoin on both sides in the gear wheel axial direction. In the middle gear wheel axial section 3, the module rrn is constant throughout. In addition, the tooth parameters which are directly proportional to the module rrn are in the middle gear wheel axial section 3, that is to say, among other things, the tip diameter da and the Root diameter df constant throughout. In the middle gear wheel axial section 3, the gear wheel 1 can preferably be designed as a standard gear wheel, in which the tooth parameters are determined as a function of the module rrn by means of the above equations.

In contrast to the middle gearwheel axial section 5, the module rri2 does not remain constant in the respective lateral gearwheel axial section 5 of the gearwheel 1, but is continuously reduced in the axial course up to the respective gearwheel end face 7. In addition, the tip diameter da is reduced in each lateral gear wheel axial section 5, from a maximum value damax to a minimum value damin (FIG. 2). The reduction in the tip diameter da can take place with a simultaneous increase in the root diameter df. In this way, the strength is increased at the end faces 11 of the gear 1. The gear wheel 1 is therefore designed in the lateral gear wheel axial sections 5 as a special shape deviating from the standard gear wheel. The gear wheel 1 shown in FIG. 1 or 2 is produced with the aid of a gear cutting machine indicated in FIG. 3 which has a generating grinding worm 9.

To make the invention easier to understand, reference is first made to a gear cutting machine known from the prior art, as indicated in FIG. In FIG. 8, a gear grinding machine is indicated in a roughly schematic representation of the principle insofar as it is necessary to understand the invention. The basic structure and a process control in the generating grinding process are known, for example, from DE 10 2015 209 917 A1, according to which a continuous generating grinding process can be carried out.

In FIG. 8, the gear cutting machine has a cylindrical generating grinding worm 9 rotating about a worm axis B. This is in a generating grinding process step in chip engagement with tooth gaps of the gear wheel 1 rotating about a gear axis C. The chip engagement takes place at a contact point K between a gear worm flank and a gear tooth flank. The roller worm 9 has a worm gear G with in cross-section trapezoidal screw thread profile. The worm thread runs helically around a base body 19 of the generating grinding worm 9.

During the hobbing, the generating grinding worm 9 is _{adjusted by a feed f z} in the feed direction z in FIG. The contact point K is coupled with the movement of the feed movement f _{z of} the pitch worm 9 along the tooth width b of the gearwheel 1. In addition, the generating grinding worm 9 is adjusted with a shift movement f _y along its axis of rotation B during generating grinding, in order to extend the service life of the generating grinding worm 9.

The gear grinding machine has an electronic control unit 21 in FIG. A software program is stored in the electronic control unit 21, by means of which the actuating drives for the fully automatic implementation of a generating grinding step and a dressing step are controlled with control signals. The control signals are used to set the control parameters of the machine components (i.e. tool carrier, turret, workpiece carrier and dressing unit), i.e. positioning movements in the spatial directions x, y, z and / or spindle speeds nw.

In contrast to FIG. 8, FIGS. 3 to 5 illustrate a rolling machining process according to a first exemplary embodiment, by means of which, for example, the gear wheel 1 shown in FIGS. 1 and 2 can be produced, the module m of which in each machining plane E1, E2 (Figures 3a, 3b) remains constant, but varies over the tooth width b. The rolling worm 9 used in the rolling machining process has a conical shape, as shown in FIGS. 4 and 5. In the rolling process, the rolling worm 9 - in addition to the feed movement f _z - an additional further axis movement As-i, AS2 is impressed in order to use the Gear width b to generate a module change. The axis movement required for such a module change in the first embodiment is an axial movement As-i, AS2 of the roller screw 9 in the roller screw axial direction B, ie an infeed movement in the infeed direction y.

An exemplary process management is illustrated in FIGS. 3a and 3b. For the sake of clarity, only (dashed) pitch worm flanks are indicated in FIGS. In FIGS. 3a and 3b, the pitch worm 9 is adjusted in the feed direction z into different feed positions, of which only a first feed position VP1 and a second feed position VP2 are indicated in FIGS. 3a and 3b. A machining plane E1, E2 is assigned to each of the feed positions VP1, VP2. The machining planes E1, E2 are each aligned at right angles to the gear axis C. In each of the processing planes E1, E2, a module m is generated locally at the contact point K with material removal. The pitch worm 9 remains in the respective feed position VP1, VP2 until at least one complete gear wheel revolution has taken place, so that an identical local module mi, rri2 is generated in the respective machining plane E1, E2 for all teeth of the gear wheel 1 . Subsequently, the rolling worm 9 is moved into a further feed position _{via a feed movement f z.}

In FIG. 3 a, the conical roller worm 9 is shown in the first feed position VP1 by way of example. In the first feed position VP1, the pitch worm 9 is axially adjusted by a first adjustment path Asi (FIG. 3). As a result, in the first feed position VP1, the conical roller screw 9 with a predefined active roller screw diameter removes material at the contact point K in order to generate a first module rrn in the first processing plane E1 (see cross-hatching in FIG. 3a). After generating the gear 1 in the first machining plane E1 (FIG. 3a), the worm 9 is advanced in the feed direction z up to the second feed position VP2 (FIG. 3b). In the second processing plane E2 assigned to the second feed position VP2, a different second module rri2 (see oblique hatching in FIG. 3b) is generated. In the second feed position VP2 (Figure 3b), the conical roller worm 9 is therefore axially adjusted by a second adjustment path ÄS2 (Figure 3), whereby the active roller screw diameter at the contact point K changes (that is, increased or decreased depending on the axial direction). This also changes the rolling worm material removal in the second processing level E2, so that the module rrn (see oblique hatching in FIG. 3b), which is different from the first processing level E1, is generated in the second processing level E2.

In the conical roller grinding worm 9, a roller screw outer diameter in FIG. 5 is continuously reduced from a large diameter roller screw face 13 to an axially opposite small diameter roller screw face 15.

Due to the conical shape of the rolling worm 9, a shifting movement f _y (see FIG. 8) of the rolling worm 9 along its axis of rotation B must be dispensed with in the rolling machining indicated in FIG. Instead, the electronic control unit 21 in FIG Module m varying over the face width b is generated.

In the figure 4 or 5a, the conical generating grinding worm 9 is realized with two threads with a first worm thread G1 and a second worm thread G2. The first worm thread G1 and the second worm thread G2 can each be different from one another Have screw thread profiles 17 (Figure 5). In generating machining, the first module area rrn can be generated in the middle gear wheel axial section 3 (FIGS. 1 or 2) by means of the first worm thread G1, while the second module areas rri2 can be generated in the outer gear wheel axial sections 5 with the help of the second worm thread G2.

As an alternative to FIG. 5a, FIG. 5b shows another conical roller grinding worm 9, in which the diameter of the roller screw base body 19 is continuously reduced between the large diameter roller screw end face 13 up to the axially opposite small diameter roller screw face 15. In the opposite direction, the profile height h of the screw thread profile 17 increases continuously from the small-diameter roller screw end face 15 to the axially opposite large-diameter roller screw end face 13.

In the figure 6, the gear cutting machine is shown according to a further embodiment, in which the generating grinding worm 9 is cylindrical. In the generating grinding machining indicated in FIG. 6, the feed movement f _{z of} the generating grinding worm 9 takes place in the feed _{direction z and the shifting movement f y of} the generating grinding worm 9 in the spatial direction y. The feed movement f _z and the shift movement f _y are superimposed on further axis movements S, R of the generating grinding worm 9 in FIG. In FIG. 6, the further roller worm axis movement is not an adjusting movement along the roller screw axis B, but rather a pivoting movement S of the roller grinding worm 9 with a pivot angle a about a pivot axis A and / or a radial movement R of the roller grinding worm 9 axially parallel to the roller grinding worm axis B. in order to generate a module m which varies over the tooth width b of the gearwheel 1. The pivot axis A is aligned approximately axially parallel to the gear axis C in FIG. In FIGS. 1 to 7, the invention is explained on the basis of continuous generating grinding machining, which represents a method for hard fine machining of tooth flanks. The invention is not only applicable to continuous generating grinding, but - due to the same kinematics - also applicable to continuous hobbing, which represents a method for soft fine machining of tooth flanks. Correspondingly, in FIG. 7, the worm gear 9 is implemented as a conical worm gear that is used in continuous hobbing.

The geometry of the hobbing worm 9 shown in FIG. 7 is largely identical to the hobbing worm 9 illustrated with reference to FIG. 4. Reference is therefore made to the previous description. In contrast to FIG. 4, the leg threads G1 and G2 in FIG. 7 do not run continuously around the screw base body 19, but are interrupted at cutouts. The recesses are arranged in alignment one behind the other in the axial direction B, which results in chip spaces through which chips can be transported away.

The invention is not limited to the production of gears with straight teeth. Instead, the method according to the invention can also be used to produce gears with helical gears. For this purpose, the pitch worm 9 is inclined at an angle with respect to the gear wheel axis of rotation C.

A further exemplary embodiment is shown in FIGS. 9 to 12, the basic structure of which is essentially identical to the exemplary embodiment shown in FIG. 3. As can be seen from FIG. 9, the only axial movement of the worm gear 9 is an infeed movement As in the infeed direction y, that is, along the worm gear axis B. In addition, in FIG . In contrast to FIG. 3, the pitch worm 9 in FIG. 9 is not designed in a conical shape, but rather has a bulge or crown in cross section (FIG. 10). Correspondingly, the worm gear module mw is a function mw (l) of the worm gear Length I designed. A special feature of the rolling worm geometry indicated in FIG. 10 is that it simulates the gear wheel module to be generated, which also changes as a function of the tooth width b. As shown in FIG. 10, the pitch worm length I extends between a worm thread start section 23 on one pitch worm end face 13 and a worm thread end section 25 on the opposite pitch worm end face 15, with intermediate worm thread sections in between. Overall, a cambered worm thread profile is thus obtained in cross section, which is symmetrical with respect to a central transverse plane of the pitch worm 9.

By means of the rolling worm geometry shown in FIG. 10, a special rolling machining process can be implemented, which is described below with reference to FIGS 23 brought into cutting engagement with the gear wheel 1 in a transverse movement Q (FIG. 10), specifically in a start feed position VPstait (FIG. 11) with an assigned start machining plane Estait, in which the gear wheel 1 is machined. The start machining plane Estait is located directly on the gear wheel face 20 (FIG. 11). At the start of the process tstart, the worm thread start section 23 is brought into cutting engagement with the gearwheel 1 in the start machining plane Estait. In the start processing level Estait a start module m _s tart in the gear 1 is produced. After completion of the machining in the starting machining plane Estait, both an infeed movement As of the pitch worm 9 in the infeed direction y and a synchronized feed movement f _z in the feed direction z take place. By means of the feed movement f _z , the gear wheel 1 is brought from the start feed position VPstait into an intermediate feed position, while the feed movement As disengages the worm thread start section 23 and an intermediate worm thread section engages the gear wheel 1 is brought. As a result, in the intermediate processing plane assigned to the intermediate feed position, a (compared to the start module mstart different) intermediate module generated. After completion of the machining in the first intermediate machining plane E2, the same process cycle takes place for any further intermediate machining planes.

At the end of the process tend (Fig. 12) the gear 1 is _{adjusted from its current intermediate feed position with a feed movement f z} to a final feed position VPend, in which the worm gear 9 machines the gear 1 in the final machining plane Eend. At the same time, the pitch worm 9 is adjusted in the feed direction y in a synchronized feed movement As, so that the worm thread end section 25 in the final machining plane Eend is in cutting engagement with the gear wheel 1 to create an end module in the final machining plane Eend m _e nd to produce.

It should be emphasized that in the process sequence according to FIGS. 9 to 12, all of the infeed movements As are in the same direction in the infeed direction y. The sum of all taking place during the process infeed As corresponds to the Wälzschnecken length I between the Schneckengang- start portion 23 and the worm gear-end portion 25. With the reference to FIGS. 9 to 12 illustrated process flow, the feed movements _{can, for} f and the movements As uninterrupted of the chip engagement between the worm gear 9 and gear 1 take place.

A further exemplary embodiment of the invention is described with reference to FIG. 13, the process arrangement of which is essentially identical to the exemplary embodiment shown in FIG. 9. In contrast to FIG. 9, in FIG. 13 the gear 1 to be machined in the generating process is a first gear component of a gear stack 27, in which the first gear 1 with at least one not yet hobbed second gear 29 on a gear (not shown) Carrier is stored. The two gears 1, 29 are aligned in FIG. 13 along the gear axis C in alignment with one another. The rolling machining of the first gear 1 takes place as illustrated with reference to FIGS. 9 to 12. During the hobbing of the first gear 1, the not yet hobbing second gear 29 can already be slightly in cutting engagement with the worm gear 9, as a result of which preliminary machining takes place. After the completion of the generating of the first gear 1, the generating of the second gear 29 follows without interruption. In this case, the end feed position VPend in the completed generating machining of the first gear 1 forms the start feed position VPstait for the subsequent generating machining of the second gear 29.

In the rolling machining of the second gear 29, the feed movements f _z and the infeed movements As - in comparison with the completed rolling machining of the first gear 1 - are each aligned in the opposite direction.

In order to avoid an interruption of the rolling process of the gears 1, 29, it is preferred if, while the rolling machining of the second gear 29 is in progress, the first gear 1 that has already been rolled is detached from the gear stack 27 by means of a transfer unit (not shown) and to a storage station or to a is transferred to another processing station.

With regard to the mass production of gears, it is preferred if, in the generating process, the axial movement of the worm 9 and / or the gear 1 alone is the infeed movement As in the infeed direction y, without radial movement R and without pivoting movement S. In addition, it is with a view to mass production, this is advantageous if, while the second gear 29 is being produced, the first gear 1 which has already been produced is detached or unloaded from the gear stack 27. Analogously to this, the gear wheel stack 27 can be equipped with at least one further gear wheel that is still to be processed while the hobbing is in progress. REFERENCE LIST

1 gear

3 middle gear axial section

5 lateral gear wheel axial section

7 face

9 gear worm

13, 15 gear worm faces

17 worm thread profile

19 gear worm body

20, 22 gear end faces

21 electronic control unit

23 Auger start section

25 End worm thread section

27 gear stacks

29 second gear

G, G1, G2 worm flights

B screw axis

D screw rotation

C gear axis

R radial movement

S swivel movement

A swivel axis b face width

K contact point

E1, E2, Estait, Eend machining levels

VP1, VP2, VPstart, VPend feed positions mi, rri2 module a swivel angle z feed direction fz feed movement fy shift movement tstart process start tend process end

I length of gear worm

Q lateral movement

Claims

PATENT CLAIMS:

Process for generating, in particular gear hobbing or generating grinding, of a gear (1) of any type of toothing, such as straight or helical gearing or the like, by means of a gear worm (9) which, during generating, in a generating direction of rotation (D) about a gear worm axis (B) is driven, wherein the worm gear (9) is in cutting engagement with the gear (1) rotating about a gear axis (C), namely at a contact point (K) between a worm gear flank and a gear tooth flank, wherein the contact point (K) is displaced along the gear axis (C) in a feed movement (f _z ) over a tooth width (b) of the gear wheel (1), and in the generating process the generating worm (9) is controlled in such a way that in each machining plane (E1, E2, ...) at right angles to the gearwheel axial direction (C), all gearwheel teeth each have a constant module (m), characterized in that the generating worm (9) and / or the gearwheel (1) executes an axis movement (As, R, S) by means of which the module (m) changes at least partially over the tooth width (b).

Method according to claim 1, characterized in that in the rolling machining process the rolling worm (9) and / or the gear wheel (1) is adjusted in the feed direction (z) into different feed positions (VP1, VP2, ...), and that in particular the feed positions (VP1, VP2, ...) are dependent on the axis movements (As, R, S) and on the face width (b).

Method according to Claim 2, characterized in that each feed position (VP1, VP2, ...) is assigned a processing plane (E1, E2, ...) at right angles to the gear wheel axial direction (C), in which all teeth of the gear (1) are formed with an identical module (m).

4. The method according to claim 3, characterized in that the contact point (K) is movement-coupled with the shifting

Is feed position, and / or that the worm gear (9) remains in each feed position (VP1, VP2, ...) until at least one complete gear wheel revolution has taken place, so that all teeth of the gear wheel, in particular at the contact point (K) (1) are machined to form a constant module (m).

5. The method according to claim 3 or 4, characterized in that in the rolling process, the axis movement (As, R, S) is controlled such that the module (mi) generated in a first feed position (VP1) from one in a second Feed position

(VP2) differentiates the module (rri2) generated, but the module (rrn, rri2) remains constant in the machining plane (E1, E2, ...) assigned to the respective feed position (VP1, VP2). 6. The method according to claim 3, 4 or 5, characterized in that the axis movements (As, R, S) are interpolated according to the process conditions as well as simultaneously and sequentially, i.e. in each processing plane (E1, E2, ...). 7. The method according to claim 6, characterized in that in each

Processing level (E1, E2, ...) the axis movements (As, R, S) are controlled simultaneously so that all gear teeth are formed with an identical module (m) in the respective processing level (E1, E2, ...) .

8. The method according to claim 5, 6 or 7, characterized in that after completion of the machining in a first

Working level (E1) the cutting engagement between the worm gear (9) and the gear wheel (1) is interrupted, so that the worm gear (9) is adjustable from the current first feed position (VP1) into the following second feed position (VP2), and that in the second feed position (VP2) the worm gear (9) is brought back into cutting engagement with the gearwheel (1) and chip machining is continued in the second machining plane (E2) assigned to the second feed position (VP2).

9. The method according to claim 8, characterized in that the rolling worm (9) is conical, so that in particular a rolling worm outer diameter active at the contact point (K) extends continuously from a large-diameter rolling worm end face (13) to an axially opposite one small diameter gear worm face (15) reduced, and that for a module change over the tooth width (b) the conical gear worm (9) and / or the gear wheel (1) by an infeed path (Asi, ÄS2) along the gear screw axis ( B. Face width (b).

10. The method according to claim 9, characterized in that the diameter of the rolling screw base body (19) between the two rolling screw end faces (13, 15) remains constant throughout, and that the screw thread profile (17) of the worm thread (G; G1, G2 ) varies between the two roller screw end faces (13, 15), and that in particular the profile height (h) of the worm thread profile (17) continuously decreases from the large diameter roller screw face (13) to the axially opposite small diameter roller screw face (15).

11. The method according to claim 9, characterized in that the diameter of the rolling screw base body (19) between the large diameter rolling screw end face (13) continuously up to the axially opposite small diameter roller screw end face (15) is reduced, and that in the opposite direction the profile height (h) of the worm thread profile (17) is continuously reduced from the small diameter roller screw end face (15) to the axially opposite large diameter roller screw end face (13) .

12. The method according to any one of the preceding claims, characterized in that the axis movement is a pivoting movement (S) of the roller screw (9) with a pivot angle (a) and / or an in particular axially parallel radial movement (R) axially parallel to the roller screw axis (B) , and that in particular the pivot axis (A) is aligned axially parallel to the gear wheel axis (C), and / or that, if necessary, the gear wheel (1) is swiveled by a compensating swivel angle in order to achieve interference-free cutting engagement between the pitch worm (9) and the gear (1).

13. The method according to claim 12, characterized in that the three axis movements (As, R, S) in each processing plane (E1, E2, ...) can be controlled in any combination, in particular in the following combinations:

- Either only radial movement (R), only pivoting movement (S) or only travel (As) along the roller worm axis (B);

- Either a paired combination of radial movement (R) and pivoting movement (S); from radial movement (R) and travel (As); from swivel movement (S) and travel (As); or

- all three axis movements (As, R, S) together.

14. The method according to claim 11, characterized in that for

Tool life extension during machining in the respective machining plane (E1, E2, ...) a shift movement (f _y ) of the

Rolling worm (9) takes place along its rolling worm axis of rotation (B), _{and that the shift movement (f y} ) is dispensed with, particularly when using a conical roller worm (9).

15. The method according to any one of the preceding claims, characterized in that the gear (1) in the finished state has at least one first gear section (3) with a first module area (mi), in which the module is as a function (m (b )) changes from the tooth width (b), and has a second gearwheel section (5) with a second module area (rri2), and / or that the pitch worm (9) multi-thread with at least two helically around a pitch circle base body (19) extending worm threads (G1, G2) and / or that in particular the first worm thread (G1) and the second worm thread (G2) are constructed with mutually different worm thread profiles (17), and that during the rolling machining by means of the first worm thread (G1 ) the first module area (rrn) is generated and the second module area (rri2) is generated by means of the second worm gear (G2).

16. The method according to any one of the preceding claims, characterized in that the hobbing according to the invention is a process step in a process chain for manufacturing the gear (1), and that the process chain can have further conventional hobbing and / or generating grinding process steps in any way.

17. The method according to any one of the preceding claims, characterized in that in the finished state of the gear (1) for the module (m) directly proportional pitch circle diameter (do) the following polynomial equation applies: do (b) = ao + ai b + a2 b ² + a3 b ³ + ... + a _n b ⁿ , where ao, ai, a2, a3, a _{n are} constants; and that In the hobbing, the control of the worm gear (9) and / or the gear-wheel tool carrier is carried out on the basis of the polynomial equation.

18. The method according to any one of the preceding claims, characterized in that the gear cutting machine has a dressing tool with which the pitch worm (9) can be dressed, and / or that by means of the method gears with straight or helical teeth can be finely machined.

19. The method according to any one of claims 1 to 8, characterized in that the roller screw module (m _w ) changes as a function (m _w (I)) of the roller screw length (I), namely between a worm thread start section (23) on a roller screw end face (13) and a screw thread end section (25) on an opposite roller screw end face (15), in particular with at least one intermediate screw thread intermediate section, and that in particular the pitch as a function of the roller screw length ( I) changing gear worm module (m) simulates the gear module (m).

20. The method according to claim 19, characterized in that the pitch worm (9) results from a transformation of the gear module (m), which is a function (m (b)) of the tooth width (b), and that in particular applies that the greater the worm length (I), the greater the accuracy of the gear machining.

21. The method according to claim 19 or 20, characterized in that, in preparation for a process start (tstait), the worm thread start section (23) is brought into cutting engagement with the gear wheel (1), specifically in a start feed position ( VPstart) with an assigned start machining plane (Estait), which is located directly on a gear wheel face (20).

22. The method according to claim 20 or 21, characterized in that after the process start (tstart) the worm thread start section (23) in the start processing plane (Estait) machines the gear (1), and that in the further course of the process the worm thread - Intermediate section in an intermediate machining plane (E2) machined the gear wheel (1), and that at the end of the process (tend) the worm thread end section (25) in an end machining plane located on an opposite gear wheel end face (22) ( Eend) machined the gear (1).

23. The method according to claim 21 or 22, characterized in that at the start of the process (tstait) the worm thread start section (23) in the start feed position (VPstait) is in cutting engagement with the gear (1), so that in a start module (m _start ) is generated on the start machining level (Estait), and that after the machining is completed in the start machining plane (Estait), both an infeed movement (As) in the infeed direction (y) and a synchronized feed movement (f _z ) takes place in the feed direction (z) up to at least one intermediate feed position (VP2), and that in the intermediate feed position (VP2) the intermediate worm thread section in the intermediate processing plane (E2) has an intermediate module (rri2 ) generated.

24. The method according to claim 22 or 23, characterized in that at the end of the process (tend) the pitch worm (9) and / or the gear (1) from the intermediate feed position with both a feed movement (f _z ) in the feed direction (z ) as well as a synchronized feed movement (As) in the feed direction (y) up to an end feed position (VPend), in which a worm thread end section (25) in the end processing plane (Eend) an end module (rriend ) so that the gear (1) is finished.

25. The method according to any one of claims 19 to 24, characterized in that the rolling machining process Axial movement of the pitch worm (9) and / or the gearwheel (1) is solely the feed movement (As) in the feed direction (y), in particular without radial movement (R) and pivoting movement (S).

26. The method according to claim 23, 24 or 25, characterized in that in the course of the process all infeed movements (As) are rectified in the infeed direction (y), and / or that the sum of all infeed movements (As) of the pitch screw length (I ) corresponds between the worm thread start section (23) and the worm thread end section (25).

27. The method according to claim 23, 24, 25 or 26, characterized in that the feed movements (f _z ) in the feed direction (z) and the feed movements (As) in the feed direction (y) without interrupting the chip engagement between the pitch worm (9 ) and the gear (1).

28. The method according to any one of claims 19 to 27, characterized in that the gear (1) to be machined in the rolling machining process is a first gear (1) part of a gear stack (27), in which the first gear (1) with at least one second gearwheel (29) not yet rolled are mounted on a gearwheel carrier, and that the two gearwheels (1, 29) are aligned in the gearwheel axis (C).

29. The method according to claim 28, characterized in that the not yet rolling-machined second gear (29) is already slightly in chip engagement with the worm gear (9) during the rolling machining of the first gear (1) and is thereby preprocessed.

30. The method according to any one of claims 25 to 29, characterized in that after completion of the rolling machining of the first gear (1), the rolling machining of the second gear (29) follows without interruption.

31. The method according to claim 30, characterized in that the final feed position (VPend) in the completed rolling machining of the first gear (1) forms the starting feed position (VPstait) for the subsequent rolling machining of the second gear (29).

32. The method according to claim 31, characterized in that in the subsequent rolling of the second gear (29) the feed movements (f _z ) and the infeed movements (As) - in comparison with the completed rolling of the first gear (1) - each in the opposite direction take place.

33. The method according to claim 30, 31 or 32, characterized in that, while the second gear (29) is being generated, the first gear (1) that has already been generated is released or discharged from the gear stack (27), and / or that at ongoing

Rolling machining of the gear stack (27) can be equipped with at least one further gear still to be machined.