Method and device for machining depressions in helical toothings

Abstract

The invention relates to a method for producing and machining toothed workpieces (1), the toothing being a blind toothing having a toothing region (A) which forms a flank depression region (B) in which the base of a flank depression extends in a recessed manner with respect to the tooth flank into a fine-machining region (C), such that, in a fine-machining step, an end portion of a honing tool moves only in this depression region (B). The flank depressions are formed by means of an undercutting tool so that flanks (9) of the flank depressions are produced which extend in parallel with one another.

Description

Description Method and device for machining troughs of helical gears field of technology

[0001] The invention relates to a method for producing and machining toothed work wheels, wherein in a first machining step a toothing is introduced into a substantially toothless workpiece which is driven in rotation about a first tool axis using a first cutting edge tool, in particular a gear skiving tool, wherein the tooth flank of a tooth of the toothing extends over a toothing region of the workpiece, and in a further machining step the toothing region is honed, and a device for carrying out the method. State of the art

[0002] Geared work wheels are manufactured through a number of consecutive work steps. Power skiving processes, among others, are used to produce internal and external gears on work wheels. A wide variety of gears can be produced using power skiving. Both straight-toothed and helical-toothed workpieces can be manufactured. After power skiving and heat treatment, such as hardening, the gearing is finely machined by honing / grinding. During honing (here gear honing), the workpiece interacts with a honing tool, such as a honing wheel, which has the shape of a gear rim with a complementary geometry to the workpiece's gearing. The abrasive particles carried by the honing wheel create a frictional friction under dynamic conditions in which fine machining... The desired fine machining of the workpiece's tooth flanks is carried out by frictionally moving the honing wheel's teeth, for example, in an oscillating motion, over the tooth flanks. During this fine machining, the honing wheels wear out. To prevent the edge area of the honing wheel's fine machining teeth adjacent to the face from breaking off due to contact with the tooth flanks, the edge area should be free during machining. When honing straight or helical gears that taper open in the direction of tooth flank extension, as is known from the prior art, the width of the honing wheel is selected so that it is greater than the width of the workpiece to be machined.This means that in the machining position, in which the workpiece and work gear teeth mesh, the edge region of the honing wheel protrudes beyond the work gear in the axial direction of the work gear from the tooth flanks to be machined, so that the edge region of the honing wheel does not contact the tooth flanks. During machining of the workpiece, an oscillating movement of the honing wheel, for example, is controlled such that the edge region of the honing wheel does not contact the workpiece, even during machining. DE 102015 111 663 A1 discloses a corresponding method for honing helical gears that taper open in the direction of tooth flank extension. However, in the case of helical blind gears in particular, it is not possible for the edge region of the honing tool to protrude beyond the work gear because the tooth flanks do not taper open in the direction of extension.

[0003] DE 10 2015 104 242 A1 discloses a method in which, in a first machining step, a straight toothing or helical toothing is introduced into a work wheel which is driven in synchronous rotation using a rotary skiving wheel, and in a second machining step, at least some of the teeth of the Gears are machined using a metal-cutting process. Tooth machining may include, among other things, the insertion of backings.

[0004] DE 10 2008 037514 A1 describes a method for gear cutting by skiving. The blank can be internally or externally toothed with a peripherally toothed skiving wheel. For this purpose, the workpiece and tool are driven in synchronous rotation. The workpiece axis and the tool axis are at an axial cross angle to each other, so that the skiving wheel performs a skiving motion in which the cutting edges of the skiving wheel's cutting teeth move through the workpiece in the direction of the tooth extension and simultaneously perform a rolling motion.

[0005] DE 41 14341 C2 describes a machine tool having a fly cutter with which helical gearing can be introduced into a workpiece, the helical course of the gearing being generated by a phase shift in the synchronous operation of the workpiece and the tool.

[0006] DE 10 2014 108438 A1 describes a machine tool and a method for machining backings into the left and right tooth flanks of a toothed work gear by skiving. The work gear and the backing tool are continuously driven in rotation, with the workpiece axis and tool axis arranged at an axes-cross angle to each other. The cutting teeth engage the tooth flanks to remove chips, with a chip being removed at an angle of 2.5° to 17° to the right or left. 6° to 17° to the left tooth flank is created, which extends inward towards the tooth base. This back- The contact flanks serve as a supporting surface for the engagement of a counter tooth flank of a counter gear.

[0007] DE 102005042735 A1 discloses a method and a device for manufacturing gears with backed tooth flanks. Here, the workpiece and tool are driven in rotation by means of spindles at a fixed speed ratio. In independent machining steps, each of the two tooth flanks of a tooth of the gearing is machined using a rotationally driven cutting edge tool with a rotating fly cutter.

[0008] DE 19964396 B4 describes a post-machining of a straight-toothed gear using a backing tool with which the tooth flanks of previously manufactured teeth can be machined.

[0009] DE 4200418 Gl describes a method for producing deposits on straight internal and external gears of toothed workpieces, in which the cutting edge tool and the workpiece rotate synchronously, wherein the cutting edge describes a hypocycloid or epicycloid when the cutting edge rolls relative to the workpiece in such a way that the cycloid branch plunging into the gear to be machined approximately coincides with the pressure angle of the gear to be machined.

[0010] DE 41 22460 Gl also discloses a method for producing backings on straight internal gears, wherein the backing tool is a skiving wheel.

[0011] DE 10 2017006 651 A1 describes a method for producing a gearing, wherein, in a first process step, a straight or helical gearing is produced. In a second process step, a deposit is created in this gearing. In a third process step, the gearing produced in the first process step is finely machined without the gearing machined in the second process step being machined.

[0012] DE 10 2020 118 384 A1 describes a deburring tool with several inclined end face sections, in each of which a deburring tool is located in a pocket. Summary of the invention

[0013] The object of the present invention is to provide a method with which gears, in particular helical blind gears, can be machined in such a way that the wear of the peripheral edges of the honing tool during honing of these gears, in particular blind gears, can be minimized, and to provide a device for carrying out the method, wherein a blind gear is understood here to be a gear that extends only over an axial section of a workpiece. In the region of one end of the gear, the radial distance of the tooth root from the axis of the workpiece can increase up to the radial distance of the tooth tip, so that a non-toothed section of the workpiece with a diameter of the gear adjoins the toothed section.The blind toothing can be produced by skiving by gradually increasing the center distance between the skiving tool and the workpiece towards the end of the toothing for external toothing and decreasing it for internal toothing. However, the blind toothing can also be produced by hobbing, gear shaping, or other methods.

[0014] The object is achieved by the invention specified in the claims, wherein initially and essentially it is provided to provide a toothed workpiece in a first step, for example to introduce helical gearing into a substantially toothless workpiece in a first machining step, and to produce flank depressions in a second machining step, for example deposits in the tooth flanks of the helical gearing, into which, in a third machining step, an end section of a fine machining flank of a fine machining tooth of a honing tool, arranged on a front side, engages without contact with the bottom (trough flank) of the flank depressions.

[0015] The helical gearing can preferably be a blind gearing. The tooth flank of each tooth of the helical gearing can extend over a toothing area of the work gear. A tooth flank line running in the longitudinal direction of the tooth flank is oriented at a first helix angle, different from zero, to the workpiece axis.

[0016] In the first machining step, the straight or helical gearing can be introduced into the essentially toothless workpiece using a first cutting edge tool that is rotationally driven about a first tool axis. The tooth flank of a tooth of the gearing can extend over a toothing area of the workpiece. The workpiece can also be rotationally driven about a workpiece axis. The first tool axis and the workpiece axis can run at an axis cross angle to each other. The first cutting edge tool can be rotationally driven in synchronism with the rotation of the workpiece. The straight or Helical gears can be machined on the inside or outside of the workpiece. The first machining step can be performed with a feed in the direction of the tooth flank extension of the spur or helical gear. The first cutting edge tool can be, for example, a skiving tool, which can have spur or helical gearing.

[0017] The first machining step can be followed by the second machining step, with the second machining step being carried out on a downstream machine tool in a production line or on the same machining machine. In the second machining step, flank grooves can be created in the tooth flanks of the gearing using a second cutting edge tool that is driven in rotation about a second tool axis. The workpiece can be driven in rotation about the workpiece axis during the second machining step. The second tool axis and the workpiece axis can preferably run parallel to one another. However, the second tool axis and the workpiece axis can also run at an axis crossing angle to one another that is different from zero.

[0018] A flank trough can be created in each or any number of the tooth flanks within the toothing area using a cutting edge of a fly cutter of the second cutting edge tool. The flank trough can extend over a flank trough area. The flank trough area can be directly adjacent to the end of the toothing. Preferably, the flank trough area extends over a blind hole protuberance. The flank trough area can be created in the area of the trailing tooth gaps arranged between two teeth of the toothing and should have the smallest possible width in order to generally reduce the area of unusable toothing. A backing process is particularly suitable for this purpose, since this process provides the necessary The depth of the clearance area can be increased, resulting in a smaller transition area compared to power skiving. The flank groove area can be located in one or both end sections of the gearing area. However, the flank groove area can also be located in another section of the gearing area.

[0019] When the cutting edge of the second cutting edge tool plunges into the tooth flanks of the gearing, the cutting edge can have such an angle to the second tool axis that the flank groove region is delimited by flanks running parallel to one another. The edges of the flanks preferably extend in a circumferential plane of the workpiece. The flank surfaces can also lie in a circumferential plane. However, it is also provided that the two flank surfaces are at an angle to one another or are curved. The shape of the flanks depends essentially on the shape of the cutting edge or the shape of the areas of the cutting edge tool adjacent to the cutting edge. The cutting edge of the second cutting edge tool can describe one or a plurality of open or closed cycloids when creating the flank groove. The cutting edge can move in a circumferential plane around the second tool axis.The surface normal of the rotational plane of the second tool can run at an angle other than zero to the second tool axis. The angle can be zero if the axes are parallel. The cutting edge can plunge into the tooth flank, oriented parallel to the tooth flank line. The straight cutting edge can run parallel to the surface normal of the rotational plane of the fly cutter. The plunge points, at which the cutting edge plunges into the tooth flank towards the tooth base, and the plunge points, at which the cutting edge emerges again, each run along a curve around the workpiece axis. The curves each lie in a rotational plane of the fly cutter, the surface normal of which is parallel to the. workpiece axis. This ensures that the flank groove area within the toothing area of each tooth flank is located at essentially the same position in the longitudinal direction of the tooth flank.

[0020] The direction of rotation of the workpiece and the direction of rotation of the second cutting edge tool can be opposite. The second cutting edge tool can rotate at a fixed speed ratio to the workpiece. The speed ratio can be selected so that the workpiece rotates by at least one tooth after one complete revolution of the tool spindle.

[0021] The flank grooves can be machined into the right and left tooth flanks in successive steps. The same cutting edge tool, for example with different, interchangeable cutting blades, or different cutting edge tools can be used for the right and left tooth flanks. To machine the other tooth flank, the direction of rotation of the second cutting edge tool and that of the workpiece can be reversed.

[0022] The flank grooves can be machined in successive steps into all right and left tooth flanks. The same cutting edge tool or different cutting edge tools can be used for this purpose.

[0023] In a third processing step, which preferably takes place after heat treatment and which, like the second processing step, takes place on a subsequent machine tool or the same machine tool in a production line, the workpiece is subjected to a fine machining Tool, preferably a honing tool, in particular machined with surface friction. The finishing tool can machine a finishing area of the workpiece arranged in the toothing area. The finishing area can border the flank groove area in an axial direction of the workpiece. The width of the flank groove area can be smaller than the width of the finishing area, for example less than a third of the width of the finishing area. The edge areas of the finishing flanks, in particular of the honing tool, arranged on the front side can engage in the flank groove areas during machining without contact with the bottom of the flank grooves. The front-side edge edges of the finishing tool, in particular the honing tool, can be free when machining the tooth flanks. The width of the flank groove can be wider than the amplitude of an oscillating honing tool.

[0024] The rotational axis of the honing tool can also be aligned at an axis cross angle or parallel to the workpiece axis.

[0025] The first and second cutting edge tools can each be supported by a tool spindle, and the workpiece by a workpiece spindle. The first and second cutting edge tools can also be driven by a common tool spindle, for example, as a combination tool. The first and second cutting edge tools, and the workpiece, can each be driven by individual electrical drives, for example, a high-speed motor.

[0026] The first cutting edge tool can be a skiving tool. In one embodiment, the skiving tool can have a skiving wheel with which the workpiece can be skived as a blank with an internal or external toothing, as described in DE 102008 037514 A1. The skiving tool can be made of high-speed steel, a carbide skiving wheel, or another hard material. The toothing of the workpiece can also be created in the first machining step by gear shaping or hobbing.

[0027] A chip-removing tool, in particular a backing tool, can serve as the second cutting edge tool. This can create the necessary depth of the flank groove area and result in a smaller transition area compared to power skiving. The fly cutter of the second cutting edge tool can be a single fly cutter or a multiple fly cutter. Each fly cutter can have one or more cutting edges. The second cutting edge tool can be an elongated body extending in the direction of the second tool axis, which body has a clamping section for clamping in a chuck, for example the chuck of a tool spindle, and a working section. The fly cutter can be arranged on an end face of the working section. The working section can have a pocket arranged in the end face with a pocket base running parallel to the end face.A contact flank for the fly cutter can extend perpendicular to the pocket base. The fly cutter can be attached to the end face, for example with a screw connection. The end face can form an inclined end face whose surface normal is oriented at a fixed angle to the tool axis. The angle of inclination of the end face can be fixed or variable, in particular variably adjustable to the angle of the tooth flank line to the workpiece axis. The end face can form an elliptical shape. The contact shoulder can extend along an edge that is oriented at a fixed angle to the major semi-axis of the elliptically shaped end face. The cutting edges of the fly cutter can. run parallel to the surface normal of the pocket base. The workpiece axis and the rotational axis of the second cutting tool preferably run parallel to one another. The cutting edge can be straight, crowned, or hollow. A straight cutting edge can preferably be inclined at an angle to the tool axis. This can correspond to the helix angle of the toothing. However, the angle can also be larger or smaller. A cutting edge can also run between two rounded sections, so that the cutting edge is delimited by two curves. Instead of the curves, straight end sections can also be provided which run at an angle to a central cutting edge section connecting them.

[0028] The workpiece axis and the tool axes can be positioned at a fixed angle to each other using positioning drives. The individual machining steps can be performed automatically one after the other, for example, using an electronic control device. The control device can operate according to a machining program. The control device can, for example, control the positioning drives and / or drive the tools and workpiece at a predetermined speed ratio, possibly with a changing phase position. The individual machining steps can, for example, be performed on successive machine tools in a production line or in a single machine tool.

[0029] The finishing tool is preferably a honing tool and can be a honing wheel with finishing teeth and abrasive tooth flanks, which is driven in rotation about a honing tool axis. The honing wheel can be in the form of a gear rim with a complementary geometry matching the toothing of the workpiece. The honing wheel can be vitrified hard Have material particles and be a dressable tool. The honing tool can have helical teeth. In one embodiment, the workpiece can have external teeth and the honing wheel can have internal teeth. During the honing of the tooth flanks, the tooth flanks of the fine machining teeth can move along the tooth flanks of the workpiece in a cutting manner in the direction of the tooth flank extension. The honing tool can perform an oscillating movement in the direction of the tooth extension. In particular, it can alternatively also be at an axial cross angle to the workpiece axis and perform a screwing movement relative to the workpiece. Short description of the drawings

[0030] Embodiments of the invention are explained below with reference to the accompanying drawings. They show: Fig. 1 is a schematic representation of a first embodiment of the first machining step, in which a straight toothing 9 having tooth flanks 5, 5' is introduced into a workpiece 1 rotating about a workpiece axis 3 by means of a first cutting edge tool 2 rotating about a first tool axis 4, Fig. 2 is a schematic representation of a second machining step of the first embodiment, in which flank grooves 18, 18' are introduced into the toothed workpiece 1 rotating about the workpiece axis 3 by means of a second cutting edge tool 7 rotating about a second tool axis, Fig. 3 is a section along the line III-III in Figure 2, wherein the second cutting edge tool 7 describes a cycloid when producing the flank grooves 18, 18', Fig. 4 is a schematic representation of a third machining step of the first embodiment, in which a straight-toothed honing tool 12, which is driven in rotation about a honing tool axis 13, with an end section 14 engaging in the flank recesses 18, 18', machines the tooth flanks 5, 5' of the toothing 9 of the workpiece 1 in an oscillating manner in the direction of the honing tool axis 13, Fig. 5 is a section along the line VV in Figure 4, wherein the internal toothing 22 of the honing tool 12 engages the toothing 9 of the workpiece 1, Fig. 6 is a schematic representation of a second embodiment of the third machining step, wherein the honing tool axis 13 of the helical honing tool 12 and the workpiece axis 3 are skewed to each other, Fig. 7 is a view in direction VII in Figure 6, Fig. 8 is a section along the line VIII-VIII in Figure 6, Fig. 9 is a schematic representation of the second machining step of a third embodiment, in which flank grooves 18, 18' are introduced into a helically toothed workpiece 1 by means of the second cutting edge tool 7, wherein the tooth flank lines 16 at a helix angle ß to the Workpiece axis 3 are oriented, Fig. 10 is an enlarged view of the flank recesses 18, 18' in Figure 9, Fig. 11 is an enlarged view of the flank troughs 18, 18' in Figure 10 introduced into the tooth flanks 5, 5' of the helical gearing of the workpiece 1, wherein the trough flank 15 runs straight and substantially parallel to the tooth flank, Fig. 12 a section along the line XII-XII in Figure 11, Fig. 12a a representation according to Figure 12 of an alternative flank recess with rounded recess flank 15, Fig. 12b a representation according to Figure 12 with an obliquely running trough flank 15, Fig. 13 is a side view of the cutter head 17 of the second cutting edge tool 7, wherein the fly cutter 11 lies in a plane whose surface normal is oriented at an angle cp to the second tool axis 8 and parallel to the cutting edge 10, Fig. 14 is a view of the front side of the cutter head 17 of the second cutting edge tool 7 in the direction XIV in Figure 13, wherein the fly knife 11 is screwed to the front side and rests against a stop 21 formed by the cutter head 17, Fig. 15 is a view of the front side of the cutter head 17 of the second cutting edge tool 7 in direction XV in Figure 13, Fig. 16 is an enlarged view of the cutting edge 10 of the fly knife 11 according to Figure 15. Description of the embodiments

[0031] When carrying out the method, a toothed workpiece 1 is prepared in a first step. The workpiece 1 can be prefabricated. However, it can also be manufactured in a first processing step immediately before further processing steps.

[0032] In such a first machining step, a toothing 9 is introduced into a toothless workpiece 1, which is driven in rotation about a workpiece axis 3, by means of a first cutting edge tool 2, which is driven in rotation about a first tool axis 3. In a first exemplary embodiment shown in Figure 1, this toothing 9 is a spur toothing, and the first cutting edge tool 2 is a helical skiving wheel. The machining of the workpiece 1 takes place in the solid material and in a single step in which all tooth flanks 5, 5' of the toothing 9 of the workpiece 1 are machined using a gear skiving process. However, the toothing can also be produced by gear shaping or hobbing, or by rolling or rolling.

[0033] Machining can also be carried out in multiple steps. The workpiece axis 3 and the first tool axis 4 are arranged at an axes-cross angle to each other, with the rotational direction of the workpiece 1 and the rotational direction of the first cutting-edge tool 2 being opposite for external gearing and the same for internal gearing. The cutting edges of the first cutting edge tool 2 engage the material in a peeling action. Meanwhile, the workpiece 1 is advanced in the axial direction 3 in the direction of arrow VS. This creates a toothing 9 extending over a toothing area A, the tooth base 23 of which runs parallel to the workpiece axis. When the cutting edges emerge from the toothing area A, a tapered tooth gap 28 is created adjoining the toothing area A, the base of which rises radially outwards. This creates the blind toothing 9 shown in cross-section in Figure 1.

[0034] In a second machining step, which can be performed without reclamping the workpiece 1, flank grooves 18, 18' are introduced into a flank groove region B within the toothing region A. In the exemplary embodiment shown in Figure 2, a second cutting edge tool 7 designed as a backing tool and driven in rotation about a second tool axis 8 is used for this purpose. The backing tool 7 comprises a fly cutter 11, which in the exemplary embodiment shown in Figure 2 is a single fly cutter. The cutting edge 10 of the fly cutter 11 machines one of the tooth flanks 5, 5' of the toothing 9 of the workpiece 1 with each complete revolution of the backing tool 7. After a complete rotation of the backing tool 7 around the second tool axis, the workpiece 1 is rotated further by at least one tooth, so that the cutting edge 10 plunges into a still unmachined tooth flank 5, 5'.As in the first machining step, the direction of rotation of the workpiece 1 and the direction of rotation of the tool 7 are opposite or parallel, with the workpiece axis 3 and the second tool axis running parallel to each other.

[0035] In the embodiment shown in Figure 2, the flank groove region B is introduced into an end section of the toothing region A near the tooth flank runout 28. However, the flank groove region B can also be introduced into another section of the toothing region A.

[0036] To create the flank grooves 18, 18', the cutting edge 10, 10' plunges into the tooth flank 5, 5' and plunges out of the tooth flank 5, 5' at exit points located below the plunge points in the direction of the tooth base 23. In doing so, the cutting edge 10, 10', 10" removes a chip, which leaves a flank groove 18, 18' in the tooth flank 5, 5'.

[0037] Figure 3 schematically shows the flight circle of the cutting edge 10, 10', 10". The flight circle shown there is achieved after traversing a cycloid. The cutting edge 10, 10', 10" can traverse a plurality of successive cycloid-shaped flight circles. With the cutting edge 10, 10', 10", a flank trough 18, 18' is milled out of the tooth flank 5, 5'. The trough flank 15 has an involute shape. This involute shape is achieved by varying the distance between the workpiece axis 3 and the second tool axis 8 and by varying the phase position. In this case, the cutting edge moves, for example, in a cutting manner, describing successive cycloids, in the direction of the tooth base 23 on an involute.

[0038] In the embodiment shown in Figures 2 and 3, the cutting edge 10, 10' runs parallel to the second tool axis 8. This results in the insertion points of the cutting edge 10 into the tooth flank 5, 5' lying in a circumferential plane with the exit points, wherein the surface normal of the circumferential plane runs parallel to the workpiece axis 3. The flanks 19 of the here- The flank grooves 18, 18' produced can run parallel to each other and at a right angle to a tooth flank line 16 running parallel to the longitudinal direction of the tooth flank 5, 5'. However, the flanks 19 can also run obliquely to the bottoms of the flank grooves, so that the flank grooves 18, 18' have a trapezoidal cross-section. The flanks can also run on rounded surfaces. The course of the flanks 19, 19' depends essentially on the shape of the edges of the cutting edge 10.

[0039] During the second machining step, all left tooth flanks 5 are machined in a first step, followed by all right tooth flanks 5' in a subsequent step. However, the left and right tooth flanks 5, 5' can also be machined simultaneously in one step using two different second cutting edge tools 7.

[0040] After the second processing step, workpiece 1 can be heat-treated, for example, the workpiece can be hardened. Following this, a third processing step follows after the workpiece has cooled.

[0041] In the third machining step, the straight toothing 9 of the workpiece 1, which has been machined, for example, by skiving and is provided with flank grooves 18, 18', is finely machined. For this purpose, as in the exemplary embodiment shown in Figure 4, a straight-toothed honing wheel 12, which is driven in rotation about a honing tool axis 13 and whose axis 13 runs parallel to the workpiece axis 3, can be used. The honing wheel 12 has straight internal teeth 22 that mesh with the straight external teeth 9 of the workpiece. The honing wheel 12 machines a fine machining area C of the toothing area A that borders the flank groove area B in the axial direction of the workpiece 1. During honing, the honing wheel 12 about a honing tool axis 13. The workpiece 1 oscillates in the direction of tooth extension. This oscillating movement is indicated by arrows in Figure 4. The direction of rotation of the workpiece 1 and the honing wheel 12 is the same.

[0042] The finishing teeth 29 of the honing wheel 12 form finishing flanks 30, 30'. The end sections 14, 14' of the finishing flanks 30, 30' adjacent to the end faces 27, 27' engage in the flank trough 18, 18' during honing, as shown in Figure 4, without contact with the trough flank 15. They therefore move between the flanks 19. The amplitude of the oscillating movement of the workpiece 1 is adjusted such that the end sections 14, 14' of the finishing flanks 30, 30' do not leave the flank trough region B in the axial direction during machining. This prevents the end sections 14, 14' from contacting the trough flank 15 during machining and thereby causing severe wear and breakage.

[0043] Figure 5 shows the straight internal toothing 22 of the honing wheel 12 meshing with the straight external toothing 9 of the workpiece 1 with the workpiece axis 3 and the honing tool axis 13 running parallel to each other.

[0044] Figures 6 and 7 show a further embodiment of the third machining step. The honing tool axis 13 runs at an axis cross angle to the workpiece axis 3. In this case, the honing wheel 12 has an oblique internal toothing 22, as can be seen in Figure 8. The axis cross angle and the helical toothing of the honing wheel 12 result in the fine machining flank 30, 30' of a fine machining tooth 29 of the honing wheel 12 sliding along the toothing area A. A feed movement, as in the embodiment shown in Figures 4 and 5 with parallel lei extending axes, is therefore not necessary. As can also be seen in Figure 8, during honing, the area of the tapered tooth gap 28 of the workpiece 1 protrudes in the axial direction beyond the toothing 22 of the honing wheel 12.

[0045] In a further embodiment of the invention, the toothing 9 introduced into the workpiece 1 is a helical toothing. This can be introduced into the workpiece 1, for example, by means of a power skiving process. The tooth flank line 16 of the helical toothing 9 runs at a helix angle ß different from zero to the workpiece axis 3 (see Figure 9).

[0046] In the second machining step, flank depressions 18, 18' are introduced into the helical gearing 9 by means of the second cutting edge tool 7 designed as a backing tool into the tooth flanks 5, 5'. The second tool axis can be oriented parallel to the workpiece axis 3, as shown by way of example in Figure 9. When the cutting edge 10, 10' of the fly cutter 11 of the second cutting edge tool 7 plunges into the tooth flanks 5, 5' of the helical gearing 9, the cutting edge 10, 10' has a second angle αp to the second tool axis 8 such that the flank depression region B is delimited by two flanks 19 (see Figure 10). The flank edges of the flanks 19 run parallel to one another and lie in a circumferential plane of the workpiece. The edges of the flanks 19 can run on parallel straight lines or curves. For an axis crossing angle of zero, the angle cp can correspond to the helix angle ß.However, the angle cp can also be larger or smaller than the helix angle ß.

[0047] The depth of the flank groove 18, 18' is variable and can be controlled by the penetration depth of the cutting edge 10, 10', for example by Variation of the distance between the parallel second tool axis 8 and the workpiece axis 3.

[0048] In the embodiment shown in Figures 11 and 12, the cutting edge 10, 10' runs parallel to the tooth flank line 16 when plunging into the tooth flank 5, 5'. This results in the depth of the flank recess 18, 18', as shown in Figure 12, remaining constant between the two flanks 19 delimiting the flank recess region B. However, the cutting edge 10, 10' can also be oriented skew to the tooth flank line 16, whereby the depth between the flanks 19 delimiting the flank recess region B varies gradually. In an embodiment not shown, the flanks 19 can form parallel surfaces that lie in a circumferential plane of the workpiece. In the case of helical gearing, one of the two flanks 19 can be undercut. Both flanks 19 run obliquely to the respective tooth flank.

[0049] Figures 12a and 12b show alternative cross-sectional shapes of the flank recesses 18, 18'. While the recess flank 15 in the embodiment shown in Figure 12 runs straight and essentially approximately parallel to the tooth flank, the recess flank 15, i.e. the bottom of the recess 18, runs there on a circular arc line.

[0050] In the embodiment shown in Figure 12b, the trough flank 15, i.e. the bottom of the flank trough 18, 18', runs obliquely to the tooth flanks.

[0051] In the third machining step, not shown here, the fine machining of the helical-toothed workpiece 1 is carried out, for example, by means of a honing wheel 12. The end sections 14 of the honing wheel 12 engage, as shown in Figure 4 as an example for a straight-toothed workpiece 1, in the second machining step into the tooth flanks 5, 5' of the helical-toothed workpiece 1.

[0052] The second cutting edge tool 7 shown in Figure 13 is a backing tool. The backing tool 7 comprises a cylindrical cutter head 17. A fly cutter 11 is arranged on the end face 24 of the cutter head 17. The end face 24 forms an elliptical inclined plane, the surface normal of which runs at an angle α to the second tool axis 8. The angle α can be adapted to the angle β such that the flank depression region B is delimited by flanks 19 running parallel to one another and extending in a circumferential plane of the workpiece.

[0053] The elliptical inclined plane forms a stop edge 21, against which a side surface 26 of the fly knife 11 rests. The stop edge 21 is rectilinear and extends at an angle y to the semi-major axis of the ellipse. The angle y can be zero or a value other than zero.

[0054] As shown in Figure 14, the fly knife 11 is attached to the end face 24 of the cutter head 17 by means of a fastening means 25. However, the fly knife 11 can also be attached to the cutter head 17 at a different position. The fastening means 25 is, for example, a fastening screw. The fly knife 11 is attached to the end face 24 in such a way that at least one cutting edge 10, 10', 10" protrudes beyond the edge of the end face 24.

[0055] In the embodiment shown in Figure 14, the fly knife 11 is a multi-blade knife having three cutting edges 10, 10', 10". The cutting edges 10, 10', 10" are at the ends of, from the fly knife- arranged on arms 11. One end of the arm projects beyond the elliptical inclined plane of the end face 24 of the cutter head 17.

[0056] When machining the workpiece 1, only one cutting edge 10 is used at a time. To change the cutting edge 10, for example, the fastening screw 25 can be loosened and the fly knife 11 can be rotated about its vertical axis until another side surface 26 rests against the stop edge 21 and another cutting edge 10', 10" protrudes beyond the edge of the end face 24.

[0057] As shown in Figure 15, the cutting edge 10 used for machining the workpiece runs on an orbit around the second tool axis 8 when the second cutting edge tool 7 rotates. The cutting edge 10 does not change its orientation to the second tool axis 8, since the angle between the workpiece axis and the second tool axis is kept constant.

[0058] A pocket bottom 34 of a pocket 33 runs parallel to the end face. As a result, the surface normal runs through the flat pocket bottom 34 at an angle ß to the second tool axis 8. The cutting edge 10 extends parallel to the surface normal of the pocket bottom 34, so that the cutting edge 10 runs skew to the rotation axis 8.

[0059] Figure 16 shows an enlarged view of an embodiment of the cutting edge 10. However, the cutting edge 10 can also be designed differently. The cutting edge 10 can have a central section running along a straight line. Edge sections adjoin the central section. In the edge sections, the cutting edge 10 can be beveled or rounded.

[0060] The above statements serve to explain the inventions covered by the application as a whole, which also independently develop the state of the art at least by the following combinations of features, whereby two, several or all of these combinations of features can also be combined, namely:

[0061] A method for producing and machining toothed workpieces, wherein in a first step a toothed workpiece 1 is provided which has a straight or helical toothing, in particular a blind toothing, wherein a tooth flank 5, 5' of a tooth 6 of the toothing 9 extends over a toothing region A of the workpiece 1, and in a second machining step a cutting edge 10, 10', 10" of a second cutting edge tool 7, which meshes with the toothing 9 of the workpiece 1 and is driven in rotation about a second tool axis 8, which is preferably a backing tool, produces a flank groove 18, 18' extending over a flank groove region B when the cutting edge 10, 10', 10" is inserted into the toothing region A, over which flank groove an end section 14 arranged on an end face 27 extends in a third machining step 14' of a finishing flank 30, 30' of a finishing tooth 29 of a finishing tool,in particular honing tool 12 is moved without contact with the bottom of the flank recess 15, which machines a finishing area C of the toothing area A adjacent to the flank recess area B in an axial direction of the workpiece 1.

[0062] A method characterized in that a rotational axis 13 of the finishing tool 12 runs parallel or skewed to the workpiece axis 3.

[0063] A method characterized in that the width of the flank groove area B is smaller than the width of the finishing area A.

[0064] A method characterized in that both opposite end portions 14, 14' of the tooth flanks 30, 30' of the finishing teeth 29 are free during the machining of the tooth flanks 5, 5'.

[0065] A method which is characterized in that the cutting edge 10 has a second angle cp to the second tool axis 8 such that the flank recess 18, 18' is delimited by flanks 19 whose edges extend in a circumferential plane of the workpiece 1.

[0066] A method which is characterized in that the first step is a machining step in which the toothing 9 is introduced into the workpiece 1 which is driven in rotation about a workpiece axis 3 using a first cutting tool 2 which is driven in rotation about a first tool axis 4.

[0067] A method characterized in that the workpiece 1 is heat treated before the third machining step.

[0068] A method which is characterized in that all right and all left tooth flanks 5, 5' of the helical gearing 9 are machined with a common or with different second cutting edge tools 7 in successive machining steps.

[0069] A method characterized in that the flank groove region B is produced in an end section of a blind toothing.

[0070] A method characterized in that the second tool axis 8 of the second cutting edge tool 7 runs parallel to the workpiece axis 3.

[0071] A method which is characterized in that the second angle cp is dimensioned such that the straight second cutting edge 10 produces a bottom of the tooth flank trough 18, 18' which runs parallel to the original course of the tooth flank 5, 5'.

[0072] A device characterized in that the controller is configured to carry out a method according to one of the preceding claims.

[0073] A tool characterized in that the surface normal 20 of the end face 24 is inclined by an angle cp different from zero to the tool axis.

[0074] All disclosed features are essential to the invention (individually, but also in combination with one another). The disclosure of the application hereby fully incorporates the disclosure content of the associated / attached priority documents (copy of the prior application), also for the purpose of incorporating features of these documents into claims of the present application. The subclaims characterize, even without the features of a referenced claim, independent inventive developments of the prior art, in particular for the purpose of filing divisional applications based on these claims. The invention specified in each claim may additionally comprise one or more of the features provided in the above description, in particular with reference numbers and / or specified in the list of reference numbers. The The invention also applies to designs in which some of the features mentioned in the above description are not implemented, in particular insofar as they are clearly unnecessary for the respective intended use or can be replaced by other technically equivalent means. List of reference symbols 1 Workpiece 21 Stop shoulder 2 first cutting edge tool 22 toothing 3 Workpiece axis 23 Tooth base 4 first tool axis 24 front face 5 tooth flank 25 fasteners 5' tooth flank 26 side surface 6 tooth 27 front side 7 second cutting edge tool 27' face side tool 28 tapered tooth gap 8 second tool axis 29 finishing tooth 9 Toothing 30 Finishing flank 10 cutting edge 30' finishing flank 10' cutting edge 31 clamping section 10" cutting edge 32 tooth base 11 cutting knives 33 bag 12 Honing tool 34 Pocket bottom 13 Honing tool axis 14 Final section 14' End section A Gearing area 15 Trough flank, backing B Flank trough area flank C Finishing area 16 Tooth flank line VS arrow 17 Work section 18 flank troughs ß angle 18' flank troughs cp angle 19 flanks Y angle 20 surface normals

Claims

Claims 1. A method for producing and machining toothed workpieces, wherein in a first step a toothed workpiece (1) is provided which has a straight or helical blind toothing, wherein a tooth flank (5, 5') of a tooth (6) of the toothing (9) extends over a toothing region (A) of the workpiece (1), and in a second machining step a cutting edge (10, 10', 10") of a second cutting edge tool (7), which meshes with the toothing (9) of the workpiece (1) and is driven in rotation about a second tool axis (8), which second cutting edge tool is preferably a backing tool, produces a flank groove (18, 18') extending over a flank groove region (B) when the cutting edge (10, 10', 10") is inserted into the toothing region (A), over which flank groove a End section (14, 14') of a finishing flank (30,30') of a finishing tooth (29) of a finishing tool (12) with a rotational axis running parallel or skewed to the rotary piece axis (3) without contact with the bottom of the flank recess (15), which machine a finishing region (C) of the toothing region (A) adjacent to the flank recess region (B) in an axial direction of the workpiece (1), characterized in that the finishing tool is a honing wheel with abrasive tooth flanks having a complementary geometry matching the toothing of the workpiece (1).

2. Method according to claim 1, characterized in that the width of the flank trough region (B) is smaller than the width of the fine machining region (A).

3. Method according to one of the preceding claims, characterized in that both opposite end sections (14, 14') of the tooth flanks (30, 30') of the fine machining teeth (29) are free during machining of the tooth flanks (5, 5').

4. Method for producing troughs, for example deposits or the like on tooth flanks of internally or externally toothed work wheels, wherein in a first step a workpiece having a toothing is provided, wherein a tooth flank (5, 5') of a tooth (6) of the toothing (9) extends in each case over a toothing region (A) of the workpiece (1), and in a second machining step with a cutting edge (10) of a second cutting edge tool (7) driven about a second tool axis (8) in each of the tooth flanks (5, 5') in the toothing region (A) a flank trough (18, 18') extending over a flank trough region (B) is produced, wherein the toothing (9) is a helical toothing in which the direction of the teeth (6) orthe tooth flank (5, 5') runs at a first helix angle (ß) different from zero to the workpiece axis (3), characterized in that the cutting edge (10) has a second angle (α) to the second tool axis (8) such that the flank recess (18, 18') is delimited by flanks (19) whose edges extend in a circumferential plane of the workpiece (1).

5. Method according to one of the preceding claims, characterized in that the first step is a machining step in which the toothing (9) is introduced into the workpiece (1) which is driven in rotation about a workpiece axis (3) using a first cutting tool (2) which is driven in rotation about a first tool axis (4).

6. Method according to one of the preceding claims, characterized in that the workpiece (1) is heat-treated before the third processing step.

7. Method according to one of the preceding claims, characterized in that all right and all left tooth flanks (5, 5') of the helical gearing (9) are machined with a common or with different second cutting edge tools (7) in successive machining steps.

8. Method according to one of the preceding claims, characterized in that the flank trough region (B) is produced in an end section of a blind toothing.

9. Method according to one of the preceding claims, characterized in that the second tool axis (8) of the second cutting edge tool (7) runs parallel to the workpiece axis (3).

10. Method according to one of the preceding claims, characterized in that the second angle (α) is dimensioned such that the rectilinear second cutting edge (10) produces a bottom of the tooth flank trough (18, 18') running parallel to the original course of the tooth flank (5, 5').

11. Device comprising a tool spindle equipped with a cutting edge tool (7), a workpiece spindle for receiving a workpiece (1) to be machined and an electrical control for controlling a positioning of the spindles, a feed and a machining of the workpiece (1) with the cutting tool (7), characterized in that the controller is configured to carry out a method according to one of the preceding claims.

12. A backing tool with an elongated body extending in the direction of a tool axis (8), which has a clamping section (31) for clamping in a chuck and a working section (17), wherein the working section (17) has a pocket (33) arranged in an end face (24) with a pocket base (34) running parallel to the end face (24) and a contact flank (21) extending perpendicularly thereto, against which a cutting blade (11) having a cutting edge (10) bears, wherein the surface normal (20) of the end face (24) is inclined at an angle (α) different from zero to the tool axis, characterized in that the cutting edge (10) projects in a radially outward direction beyond a peripheral edge of the end face (24) and runs parallel to the surface normal.

13. A method, device or backing tool, characterized by one or more of the characterizing features of one of the preceding claims.

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