TOOL AND METHOD FOR PRODUCEING DEPOSITS ON THE TEETH OF A GEAR'S TOOTHING

Description

[0001] The invention relates to a tool for creating backings on the internal or external toothing of a gear. The tool, which rotates about a tool rotation axis during use, comprises a tool shank extending along the tool rotation axis, a fastening section formed at one end of the tool shank for fastening the tool to a tool drive of a machine tool, and at least one cutting blade arranged at a fastening position provided on the circumference of the tool shank. Such a tool according to the preamble of claim 1 is known from document EP 0 550 877 B1.

[0002] The invention also relates to a method according to the preamble of claim 11 for producing deposits on the teeth of a toothing of a gearwheel, in which material is removed by machining from the flanks of the teeth of the gearwheel rotating about a workpiece rotation axis by means of at least one cutting blade which is fastened to the circumference of a tool shank of a tool which rotates about a tool rotation axis aligned longitudinally to the tool shank.

[0003] A method as described above is known from EP 0 550 877 B1. In this method, a single-tooth tool rotating on a hypocycloid or epicycloid relative to the workpiece is pushed into the gear to be machined. The respective cycloidal trajectory of the cutting edge of the tool is selected such that the cycloid branch plunging into the gear to be machined at least approximately coincides with the pressure angle of the gear to be machined. In the practical implementation of this method, a tool is used which comprises a slender tool shank, on the circumference of which two cutting blades are arranged offset from one another in the axial direction in order to simultaneously form a deposit on the front and rear edge of the respective tooth of the gear to be machined.The tool shank is clamped at one end into a tool clamping fixture of the respective machine tool, so that it protrudes freely from the clamping fixture over a significant portion of its length, which supports the cutting blades. Particularly when machining wide workpieces, this clamping can cause the slender tool shank to bend due to the loads acting on it transversely to the tool rotation axis. This can cause unacceptable form deviations, particularly in the area of ​​the front backing created by the cutting blades located further away from the tool clamping fixture.In practice, these form deviations can be counteracted by using cutting blades to produce the front backings. These blades, due to their special shape adapted to the respective machining task and situation, compensate for the form deviation of the tool shank that occurs during operation.

[0004] EP 1 644 152 A1 discloses a further method for profiling toothed workpieces, in particular for creating backings or the like on tooth flanks of internally or externally toothed gears. For this purpose, the workpiece, which rotates about a workpiece rotation axis, is machined by means of a cutting-edge tool rotating about a tool rotation axis, the cutting edge of which tool meshes with the toothing of the workpiece. The workpiece and cutting-edge tool rotate at a fixed speed ratio about their parallel axes of rotation such that the cutting direction is towards the tooth root of the toothing. As a result of a combination of variation of the center distance and variation of the phase position or the inclination of the axis position on a curve corresponding to the profile shape, superimposed on the rotational movement, the cutting-edge tool is displaced.At the same time, the cycloidal path of movement of the cutting edge relative to the workpiece, defined by the center distance, the flight circle of the cutting edge and the transmission ratio, is selected such that the incoming branch of a cycloidal loop intersects the returning branch of the same cycloidal loop.

[0005] Against the background of the state of the art explained above, the task arose to create a tool and to name a method using simple means that enable the production of geometrically precisely shaped deposits on gear teeth without the need to use specially shaped cutting inserts or to modify machine tools that have proven themselves in practice for the production of deposits.

[0006] To achieve this object, the invention proposes a tool comprising at least the features specified in claim 1 and a method in which at least the working steps specified in claim 11 are carried out.

[0007] Advantageous embodiments of the invention are specified in the dependent claims and, like the general inventive concept, are explained in detail below.

[0008] A tool according to the invention, which rotates about a tool rotation axis in use for producing deposits on an internal or external toothing of a gear, thus comprises, in accordance with the prior art set out at the outset, a tool shank extending along the tool rotation axis, a fastening section formed at one end of the tool shank for fastening the tool to a tool drive of a machine tool, and at least one cutting blade which is arranged at a fastening position provided on the circumference of the tool shank.

[0009] According to the invention, in such a tool, the diameter of the tool shank measured in a plane aligned normal to the tool rotation axis increases in the direction towards the fastening section, starting from the diameter which the tool shank has at the fastening position of the cutting blade.

[0010] A tool according to the invention thus no longer has an elongated, slender, or pin-shaped form, but is thickened, at least starting from the position at which a cutting insert is attached to the tool shank, towards the fastening section. This thickening, which increases in the direction of the fastening section, achieves a stiffness of the tool shank that increases from the fastening position towards the fastening section, precisely counteracting the bending loads that occur when the tool is in use. The geometry according to the invention and the resulting mass and strength distribution of the tool ensure that the tool deforms only within permissible tolerances, even under the loads occurring during use.As a result, an optimally precise work result can be guaranteed when creating deposits on the teeth of a gear wheel, without the need for complex tool design or complex machine control.

[0011] A particular advantage of the inventive design of a tool for producing deposits is that the diameter in the area of ​​the front section, which borders on the end face of the tool that is free during use, can be kept so small that a cutting blade mounted in this area can be brought to the respective processing point safely and without problems, even under the spatially limited conditions that usually prevail in a machine tool.

[0012] Accordingly, a particularly practical embodiment of the invention provides that the distance between the fastening position of the cutting blade and the end face of the tool shank that is free during use is smaller than the distance between the fastening position and the end of the tool shank adjacent to the fastening section. This means that at least one cutting blade is arranged on the tool shank, preferably in close proximity to the end face of the tool shank, which, during use, is moved toward the teeth of the gear workpiece to be machined.

[0013] With regard to the possibilities for optimal positioning of the cutting blade in relation to the tooth flanks of the teeth of the gear to be machined, it has proven particularly advantageous if the cutting blade's mounting position is directly adjacent to the free end face of the tool shank during use. This can mean, for example, that a receptacle is formed into the tool shank, starting from the free end face, in which the cutting blade is held in such a way that it protrudes laterally beyond the tool shank in the radial direction and can thus engage with the tooth to be machined during use.

[0014] If tools according to the invention are each equipped with only one cutting blade, they can be used to create backings on the gear being machined that are adjacent to one of the gear's faces. If such backings are also to be created on the opposite, second face of the gear, the gear is typically turned over, and the backings are then created on the previously unmachined side of the teeth.

[0015] However, with a tool according to the invention, deposits can also be created at both ends of the teeth simultaneously in a single pass. For this purpose, two fastening positions, each for a cutting blade, can be provided on the circumference of the tool shank, and of these two fastening positions, the first fastening position can be arranged at a distance from the end face of the tool shank that is free during use, which is smaller than the distance of the fastening position to the end of the tool shank adjacent to the fastening section, in particular directly adjacent to the end face of the tool shank that is free during use, while the second fastening position is arranged at a distance from the first fastening position in the longitudinal direction of the tool shank in the direction of the fastening section.The distance between the mounting positions corresponds to the distance at which the two backings are to be created simultaneously on the teeth of the machined gear. The second mounting position can be located far enough from the first mounting position that it is directly adjacent to the end of the tool shank associated with the mounting section.

[0016] Because a tool shaped according to the invention avoids the bending deformations that caused unacceptable shape deviations in the deposits produced in the prior art, a tool according to the invention can be equipped with conventionally designed cutting blades. This eliminates the need for special adaptation, particularly of those cutting blades provided at a mounting position in the front area of ​​the tool, which is associated with the free end face of the tool shank during use.

[0017] The cutting blades carried by a tool according to the invention can be designed in the manner of conventional cutting inserts to allow for easy replacement after wear. For this purpose, the respective fastening position can be formed by a receptacle, and the cutting blade arranged in the respective fastening position can be designed as a cutting insert that is held in the receptacle by a holding portion, while a blade portion of the cutting insert projects radially beyond the circumference of the tool shank.

[0018] It is possible to adapt the increase in the diameter of the tool shank provided according to the invention exactly to the bending loads actually occurring in use, for example by recording the bending loads in question in a practical test and deriving from this the optimal thickness profile of the tool shank with regard to the desired stiffening of the tool shank.

[0019] Optimum deformation resistance can be achieved by continuously increasing the diameter of the tool shank, starting from the cutting blade mounting position toward the end of the tool shank associated with the mounting section. Such a continuous increase in thickness prevents sudden load changes and the associated stresses in the tool, which could lead to premature tool failure.

[0020] A particularly practical design of a tool according to the invention based on this arises when the tool shank is shaped, at least in sections, in the manner of a cone or a truncated cone. Practical tests have shown that a component shaped in this way is not only particularly easy to manufacture, but also ensures optimized dimensional stability under the loads encountered in practice. It has been shown that a truncated or conical shape of the tool shank can always prevent bending of the tool so reliably that the requirements for manufacturing accuracy encountered in practice can be reliably met. The tool designed in this way has a conically tapered circumferential surface that encloses an angle with the tool's axis of rotation that corresponds to the angle between the tool and workpiece rotation axes.

[0021] The particular advantage of the tool according to the invention is that the tool shank can be easily manufactured as a solid body. Steel materials, which have already proven themselves in the state of the art, are particularly suitable for this purpose.

[0022] According to the above explanations, in a method according to the invention for producing deposits on the teeth of a toothing of a gearwheel, material is removed by machining from the flanks of the teeth of the gearwheel rotating about a workpiece rotation axis by means of at least one cutting blade which is fastened to the circumference of a tool shank of a tool which rotates about a tool rotation axis aligned longitudinally to the tool shank.

[0023] According to the invention, a tool designed according to the invention is used for the machining of the deposit. The tool's rotational axis is aligned at an angle greater than 0° with respect to the workpiece's rotational axis.

[0024] In the method according to the invention, the thickness profile of the tool used is thus taken into account by aligning the tool axis and the workpiece axis obliquely to each other during the creation of the deposits. The angular alignment of the tool rotation axis with respect to the workpiece rotation axis compensates for the fact that the cutting edge of the cutting blade in the tool according to the invention is aligned at an angle β with respect to the tool rotation axis.

[0025] In the particularly practical case where the cutting edge of the cutting blade of the tool according to the invention is aligned parallel to the envelope of the workpiece shank, the angle at which the workpiece rotation axis and the tool rotation axis intersect is preferably equal to the angle formed by the surface line defining the envelope with the tool rotation axis. The "envelope" here refers to the conical surface that can be created by rotating a straight surface line applied to the tool shank around the tool rotation axis.

[0026] In this case, the cutting blade has a cutting edge which is at least partially straight and which is aligned parallel to the surface line which creates the envelope of the tool shank, the angle Σ being set such that the straight section of the cutting edge is aligned parallel to the tip surface of the relevant tooth of the gear at the moment of encounter with the tooth to be machined.

[0027] In the inventive production of backings, the rotational axes of the tool and workpiece thus intersect at an axis intersection angle, as is also known, for example, from power skiving and related processes. The angular arrangement of the rotational axes relative to one another enables the tool to be brought collision-free close enough to the teeth of the gear to be machined, despite the increasing diameter of its mounting section coupled to the tool rotary drive of the respective machine tool, that the at least one cutting blade can reach the tooth it is machining.

[0028] In practice, a shape of the tool shank of a tool according to the invention has proven successful, in which an angle β of 4° to 16° results between the surface line of the tool shank and the tool rotation axis and, consequently, when carrying out the method according to the invention, also between the tool rotation axis and the workpiece rotation axis.

[0029] A particularly practical embodiment of the method according to the invention results when the cutting blade has a cutting edge which is at least partially straight and which is aligned parallel to a lateral surface enveloping the tool shank, wherein the angle β is set such that the straight section of the cutting edge is aligned parallel to the tip surface of the relevant tooth of the gear at the moment of encounter with the tooth to be machined.

[0030] The tool according to the invention and the method according to the invention do not impose any special requirements on the process for creating deposits on the gear being machined, except for the stipulation of the inventive angular alignment of the rotational axes of the tool and workpiece. Thus, the ratio of the rotational speeds of the tool and workpiece for machining can be adjusted in a known manner so that all teeth of the gear are machined in a single machining pass. For this purpose, the rotational speeds can be selected so that they have no common divisor. The geometry of the tool can be selected in relation to the geometry of the gear being machined so that the trajectory of the cutting edges of the respective cutting blade of the tool describes an "open" or a "closed cycloidal" trajectory.

[0031] The invention is explained in more detail below with reference to a drawing illustrating an exemplary embodiment. The drawings schematically show: Fig. 1 shows a tool during the production of deposits on the teeth of an externally toothed gear in a side view; Fig. 2 shows the tool according to Fig. 1 in a frontal view; Fig. 3 the tool according to the Figures 1 and 2 in a perspective view from behind; Fig. 4 an alternative embodiment of a tool for producing deposits in a side view.

[0032] The tool 1 for producing backings H on the external toothing A of a gear ZR rotates about a tool rotation axis W during use.

[0033] The tool 1 comprises a tool shank 4 extending along the tool rotation axis W, at one end 5 of which a conventionally designed fastening section 6 is formed for fastening the tool 1 to a clamping device of a tool drive (not shown here for clarity) of a machine tool (also not shown). The tool shank 4 and the fastening section 5 are made from a solid piece of a tool steel that has proven itself in the state of the art for the production of tools of the type in question.

[0034] At its end opposite the fastening section 6, which protrudes freely from the clamping of the tool drive during use, the tool shank 4 has an end face 7 having a circular basic shape with a diameter D1. Starting from the end face 7, the diameter D of the tool shank 4 increases continuously in the direction of the longitudinal direction L of the tool shank 4, which extends parallel to the tool rotation axis W, until the end 5 of the tool shank 4 associated with the fastening section 6 is reached, at which the diameter D has its greatest value D2.

[0035] The tool shank 4 thus has the shape of a truncated cone, the circumferential surface 8 of which is formed by rotating a straight surface line M around the tool rotation axis W and thus tapers conically from its thickest point adjacent to the fastening section 6 in the direction of the end face 7 of the tool shank 4 which is free during use.

[0036] The surface line M is inclined relative to the tool rotation axis W by an angle β of, for example, 5°.

[0037] Starting from the end face 7, a receptacle 9 is formed in the tool shank 4, which is laterally open towards the circumferential surface 8 and in which a conventionally designed cutting blade insert 10 with its holding section is seated. The holding section of the cutting blade insert 10 carries a cutting blade 11 which projects freely beyond the circumferential surface 8 of the tool shank 4 in the radial direction R. The cutting blade 11 is thus held at a fastening position B1 which is directly adjacent to the end face 7 of the tool shank 4, which is free during use, and thus has the greatest possible distance S from the end 5 of the tool shank 4 adjacent to the fastening section 7. The cutting blade 11 has a straight cutting edge 12 which, in the example described here, extends parallel to the circumferential surface 8 of the tool shank 4.

[0038] In use, the gear ZR rotates synchronously with the tool 1 around a tool rotation axis W. The speed ratio R1 / R2 of the speed R1, at which the tool 1 rotates around the tool rotation axis W, to the speed R2, at which the workpiece (gear ZR) rotates around its workpiece rotation axis X, is selected such that both speeds R1 and R2 have no common divisor. In this way, it is achieved in a known manner that all teeth Z of the gear ZR are evenly machined after a sufficient number of revolutions.

[0039] To produce the deposits H on the teeth Z of the external toothing A of the gear ZR, the tool 1 is positioned with its tool rotation axis W in relation to a workpiece rotation axis X in such a way that an axis crossing angle Σ is enclosed between the workpiece rotation axis X and the tool rotation axis W, which is, for example, equal to the angle β by which the surface line M depicting the circumferential surface 8 of the conical tool shank 4 is aligned in relation to the tool rotation axis W.

[0040] In this way, the circumferential surface 8 of the tool shank 4 is aligned parallel to the workpiece rotation axis X at the point of its greatest approach to the workpiece rotation axis X. Consequently, the cutting edge 12 of the cutting blade 11 is also aligned parallel to the tooth head K of the tooth to be machined at the moment of engagement with the tooth Z to be machined, and thus parallel to the workpiece rotation axis X.

[0041] In this way, despite the conicity of the tool shank 4 and the cutting edge 12 of the cutting blade 11 being aligned parallel to the circumferential surface 8 of the tool shank 4, during the machining process of the deposits H on the teeth Z of the gear ZR by the cutting blade 11, a sectional image is produced which corresponds to that which arises when deposits are introduced into the teeth of a gear using a slender but deformation-prone tool of the type described in EP 0 550 877 B1 as mentioned at the outset.

[0042] In contrast to the prior art, in which slender tools must be used to reach the location where the respective deposit is to be created, in the tool 1 according to the invention the risk of bending deformation along its tool rotation axis W is minimized in that the tool shank 4, due to its increasing thickness starting from the fastening position B1 in the direction of the fastening section 6, offers a high deformation resistance to the forces which occur during the engagement of the cutting blade 11 in the material of the teeth Z of the gear ZR and are directed transversely to the tool rotation axis W.

[0043] As a result, a high-precision production of the deposits H on the gear ZR is made possible even if the fastening position B1 for the cutting blade 11 is selected to project far freely relative to the fastening section 6 with which the tool 1 is held in the tool holder of the respective machine tool during use.

[0044] If, with tool 1, deposits H are to be produced on the gear ZR not only on the end sections of the teeth Z that are assigned to one end face S1 of the gear ZR, but also on the end sections adjacent to the opposite end face S2, then this can be done in the case of the Fig. 1 In the embodiment shown, the tool 1 can be turned about a vertical axis V as soon as the generation of the deposits H adjacent to the first end face S1 is completed, and a further machining pass can be completed with the tool 1.

[0045] In Fig. 2an example of a tool 101 is shown which enables the simultaneous generation of deposits H1,H2 on the end faces S1,S2 of the gear ZR to be machined.

[0046] For this purpose, the tool 101 has a tool shank 104 and a fastening section 106, which are formed in one piece as a solid body in the manner described above for the tool 1.

[0047] As with tool 1, tool 101 also has a receptacle formed in its end face 107, which is free during use, which, like the receptacle 9 of tool 1, is open in the radial direction R towards the circumferential surface 108 of tool 101. A conventionally shaped first cutting blade insert 110 is seated in the receptacle. The cutting blade 111 of the cutting blade insert 110 is located in tool 101 at the same fastening position B1 as the cutting blade 11 in tool 1. Here, too, the cutting edge of the cutting blade 111 is aligned parallel to the rotational axis W of tool 101.

[0048] Additionally, a second cutting blade 113 is provided on the tool 101. For this purpose, a receptacle is formed into the peripheral surface 108 of the tool 101 at a mounting position B2, which is provided approximately in the middle of the longitudinal extension of the tool shank 104. A cutting blade insert 114 is seated in the receptacle. Like the cutting blade inserts 10 and 110, the cutting blade insert 114 carries the second cutting blade 113, which projects in the radial direction R beyond the peripheral surface 108 of the conically shaped tool shank 104.

[0049] For machining the gear ZR, the tool 101, like tool 1, is aligned with its axis of rotation W in relation to the axis of rotation X of the gear ZR rotating synchronously with the tool 101 at the axis cross angle Σ and positioned so that the cutting blades 110 and 113 engage with the tooth Z to be machined. Here too, the conical shape of the tool shank 104, which increases in thickness starting from the end face 107 which is free during use, ensures that during machining, despite the transverse loads on the tool 101 occurring during machining, no deformation of the tool 101 occurs which could impair the precision of the machining result. REFERENCE SYMBOL

[0050] 1Tool for producing the backings H 4Tool shank 5End of the tool shank 4 assigned to the fastening section 6 6Fastening section 7Free end face 7 of the tool shank 4 during use 8Circumferential surface of the tool shank 4 9Receptacle 10Cutting blade insert 11Cutting blade of the cutting blade insert 10 12Cutting edge of the cutting blade 11 101Tool for simultaneously producing backings H1, H2 104Tool shank 105End of the tool shank 104 assigned to the fastening section 106 106Fastening section 107Free end face of the tool shank 104 during use 108Circumferential surface of the tool 101 110Cutting blade insert 111Cutting blade of the cutting blade insert 110 113Second cutting blade 114Second cutting blade insert βInclination angle of the surface line M relative to the tool rotation axis W ΣAxis crossing angle AExternal teeth of the gear ZR B1Mounting position of the cutting blade 11 ( Fig. 1 to 3 ) and the cutting blade 111 ( Fig. 4 ) B2Mounting position of the second cutting blade 113 ( Fig. 4 ) DDiameter of the tool shank 4 D1Diameter of the tool shank 4 at its end face 7 D2Diameter of the tool shank 4 at its end 5 HHeading H1,H2Backings KRespective head surface of the teeth Z LLongitudinal direction MGenerating surface line 8 RRadial direction SDistance S1,S2End faces of the gear to be machined ZR WTool rotation axis XWorkpiece rotation axis ZZeeth of the gear ZR ZRGear

Claims

1. Tool for creating back tapers (H, H1, H2) at an internal or external toothing (A) of a gear (ZR), wherein the tool (1, 101) rotating during use about a tool axis of rotation (W) comprises a tool shaft (4, 104) extending along the tool axis of rotation (W), a fastening section (6, 106) for fastening the tool (1, 101) to a tool drive of a machine tool, the fastening section (6, 106) formed at an end (5, 105) of the tool shaft (4, 104), and at least one cutting blade (11, 111, 113), which is arranged at a fastening position (B1, B2) provided at the circumference (8, 108) of the tool shaft (4, 104), characterised in that the diameter (D, D1, D2) of the tool shaft (4, 104) measured in a plane oriented normal to the tool axis of rotation (W) increases starting from the diameter (D1), which the tool shaft (4, 104) has at the fastening position (B1, B2) of the cutting blade (11, 111, 113), in a direction (L) directed towards the fastening section (6, 106).

2. Tool according to claim 1, characterised in that the distance of the fastening position (B1) of the cutting blade (11, 111) to the front side (7, 107) of the tool shaft (4, 104) that is free during use is smaller than the distance (S) of the fastening position (B1) to the end (5, 105) of the tool shaft (4, 104) adjoining the fastening section (6, 106).

3. Tool according to claim 2, characterised in that the fastening position (B1) of the cutting blade (11, 111) directly adjoins the front side (7, 107) of the tool shaft (4, 104) that is free during use.

4. Tool according to any one of claims 2 or 3, characterised in that two fastening positions (B1, B2) each for a cutting blade (111, 113) are provided at the circumference (8, 108) of the tool shaft (4, 104) and in that of these two fastening positions (B1, B2), the first fastening position (B1) is arranged according to any one of claims 2 or 3, while the second fastening position (B2) is arranged spaced apart from the first fastening position (B1) in a longitudinal direction (L) of the tool shaft (4, 104) in a direction towards the fastening section (106).

5. Tool according to claim 4, characterised in that the second fastening position (B2) directly adjoins the end of the tool shaft (104) assigned to the fastening section (106).

6. Tool according to any one of the preceding claims, characterised in that the respective fastening position (B1, B2) is formed by a recess (9) and the cutting blade (11, 111, 113) arranged in the respective fastening position (B1) is designed as a cutting insert (10, 110), which is held in the recess (9) with a holding section, while a cutting blade (11, 111, 113) of the cutting insert (10, 110, 114) projects in a radial direction (R) beyond the circumference (8, 108) of the tool shaft (4, 104).

7. Tool according to any one of the preceding claims, characterised in that the diameter (D) of the tool shaft (4, 104) continuously increases starting from the fastening position (B1, B2) of the cutting blade (11, 111, 113) in a direction (L) towards the end (5, 105) of the tool shaft (4, 104) assigned to the fastening section (6, 106).

8. Tool according to claim 7, characterised in that the diameter (D) of the tool shaft (4, 104) continuously increases starting from the front side (7, 107) of the tool shaft (4, 104) that is free during use in a direction (L) towards the end (5, 105) of the tool shaft (4, 104) assigned to the fastening section (6, 106).

9. Tool according to any one of claims 7 or 8, characterised in that the tool shaft (4, 104) is shaped at least in sections in the manner of a cone or a truncated cone.

10. Tool according to any one of the preceding claims, characterised in that the tool shaft (4, 104) is manufactured as a massive body.

11. Method for creating back tapers (H, H1, H2) at the teeth (Z) of a toothing (A) of a gear (ZR), in which material is removed by chip removal from the flanks of the teeth (Z) of the gear (ZR) rotating about a workpiece axis of rotation (X) by means of at least one cutting blade (11, 111, 113) fastened at the circumference (8, 108) of a tool shaft (4, 104) of a tool (1, 101) rotating about a tool axis of rotation (W) oriented along the tool shaft (4, 104), characterised in that the tool (1, 101) is designed according to any one of claims 1 to 10 and in that the tool axis of rotation (W) is oriented with respect to the workpiece axis of rotation (X) at an angle Σ greater than 0°.

12. Method according to claim 11, characterised in that the angle Σ, at which the tool axis of rotation (W) and the workpiece axis of rotation (X) are arranged angularly with respect to one another, is at least equal to an angle ß that a surface line (M), which is applied to the tool shaft (4, 104) and forms the enveloping of the tool shaft (4, 104), encloses with the tool axis of rotation (W).

13. Method according to claim 11, characterised in that the angle ß is 4° to 16°.

14. Method according to any one of claims 11 or 12, characterised in that the cutting blade (11, 111, 113) comprises a cutting edge (12) designed straight-lined at least in sections, which is oriented parallel to the surface line (M), which creates the enveloping of the tool shaft (4, 104), and in that the angle Σ is set such that the straight-lined section of the cutting edge (12), at the moment of contact with the tooth (Z) to be machined in each case, is oriented parallel to the head surface (K) of the respective tooth (Z) of the gear (ZR).