Method for producing a modification on a tooth surface of an internally toothed workpiece

Abstract

The invention relates to a method for producing modifications, for example torsions (FV1, FV2), on the tooth flanks (F1, F2) of an internally toothed workpiece using an externally toothed tool (6). In order to be able to carry out this method also with a machine tool (1) having a reduced number of adjustable axes, the invention provides that the tool (6) to be modified can be modified by arranging an internally toothed modification tool (15) on the workpiece spindle (2) of the machine tool (1) in the position provided for the respective workpiece to be honed and by engaging the modification tool (15) with the tool (6) to be modified. The width of the teeth (17) of the modification tool (15) is smaller than the width of the tool (6) to be modified, so that the modification tool (15) has to be moved along the workpiece longitudinal axis (Z1) by a distance which corresponds to a multiple of the width (D) of the teeth of the modification tool (15). The workpiece is then finished using the tool (1) modified in this way. According to the invention, an axis intersection angle (Σ A ) is provided for the modification, which remains constant during the modification. The respective tooth flank modification (FV1, FV2) is then produced during the modification only by the movement of the modification tool (15) along the tool longitudinal axis (Z1) and the tool transverse axis (X1).

Description

Technical Field

[0001] This invention relates to a method for producing a modified portion on the tooth surface of an internally toothed workpiece using an externally toothed tool on a machine tool, wherein the teeth of the externally toothed tool mesh with the teeth of the workpiece during honing. The machine tool includes a workpiece spindle having a rotary drive for rotating the workpiece about its rotation axis, an adjustment device for adjusting the workpiece along a longitudinal axis of the workpiece oriented parallel to the workpiece axis, an adjustment device for adjusting the workpiece along a transverse axis of the workpiece oriented transversely to the longitudinal axis of the workpiece, a tool spindle having a rotary drive for rotating the tool about its rotation axis, and an adjustment device for setting an axis cross angle, wherein the rotation axes of the workpiece and the tool are oriented alternately to each other at the axis cross angle during honing. Background Technology

[0002] It is well known that the behavior of spur gear teeth is not only affected by their macroscopic geometry, but also by purposefully introduced tooth surface deformations or method-related shape deviations. These shape deviations include so-called "torsion," which is the twisting of the tooth surface.

[0003] Torsion is generally undesirable, but it can be purposefully introduced as a tooth surface modification to compensate for the deformation of gear teeth under load during operation. It is known in this respect that such modifications to the tooth surface geometry of the gear can, for example, prevent tooth meshing impacts and improve the surface bearing profile of the teeth, thereby optimizing power transmission, service life, uniformity of force transmission, and noise behavior of the drivetrain.

[0004] A method is known from DE 10 2012 108 717A1 that economically produces such complex tooth surface modifications using a tool having teeth that mesh with the gear teeth during finishing. This involves forming a profile varying in width on the tool by moving a dressing wheel along the tooth surface of the corresponding tooth to be dressed during a dressing operation. The width of the teeth of the dressing wheel meshing with the tool to be dressed is much smaller than the width of the tool, thus requiring the dressing wheel to move a distance in the Z-direction several times the width of its teeth to sweep across the width of the tool. Here, the dressing wheel is axially guided through the corresponding tooth surface of the tool to be dressed in the corresponding backlash with a varying skewing angle and a varying axial cross angle relative to the tool's rotation axis in the Z-direction, so as to introduce a corresponding modification to the tooth surface geometry within the tool. The gear is then finished using the tool dressed in this manner. Therefore, the tooth surface deformation machined into the tool is transferred to the tooth surface of the gear.

[0005] The basic principle of the narrow dressing wheel used in the above method is known from DE 10 2007 043 402A1. By using such a narrow dressing wheel, the configuration of the tool to be dressed can be formed solely by the corresponding movement of the dressing wheel, thereby producing profile correction on the machined gear during the subsequent finishing process with the thus dressed tool. The shape of the narrow dressing wheel does not need to be identical to the workpiece teeth in all parameters, nor does it require complex additional control schemes in the corresponding dressing equipment. A similar method for correcting the tooth surface line of gears is proposed in DE 10 2007 043 384A1.

[0006] The method for contouring a honing tool for honing the teeth of a workpiece, as described in WO 2011 / 157830A1, is also based on using a contouring tool with a thickness significantly smaller than the thickness of the corresponding tooth to be contoured. In this method, an annular, uncontacted honing tool is clamped in a holder of the honing machine for holding the honing tool during honing, and the contouring tool is tensioned in the workpiece spindle of the honing machine. Summary of the Invention

[0007] Against the backdrop of the prior art described above, the object of the present invention is to provide a method that enables the introduction of a modified portion, particularly a torsional portion, into the tooth surface of an externally geared gear, even when using a machine tool with a reduced number of adjustable shafts.

[0008] The advantageous designs of the present invention are the same as the general inventive concept, and are explained in detail below.

[0009] In the method according to the invention for producing deformed portions, particularly torsional portions, on the tooth surface of an internally geared workpiece using an externally geared honing tool, the teeth of the externally geared honing tool mesh with the teeth of the workpiece during honing. A machine tool is used, comprising a workpiece spindle having a rotary drive for rotating the workpiece about a workpiece rotation axis, an adjustment device for adjusting the workpiece along a longitudinal axis Z1 oriented parallel to the workpiece rotation axis C1, an adjustment device for adjusting the workpiece along a transverse axis X1 oriented transversely to the workpiece longitudinal axis Z1, a tool spindle having a rotary drive for rotating the tool about a tool rotation axis E1, and a mechanism for setting the axis cross angle Σ. A In the honing process, the rotation axes C1 and E1 of the workpiece and tool are oriented alternately to each other at an angle.

[0010] The method according to the present invention includes the following working steps:

[0011] a) The tool is dressed by arranging an internally geared dressing tool on the workpiece spindle at a position set for the corresponding workpiece to be honed and by engaging the dressing tool with the tool to be dressed, wherein the width of the teeth of the dressing tool that mesh with the tool to be dressed is smaller than the width of the tool to be dressed, such that the dressing tool must move a distance along the longitudinal axis of the workpiece corresponding to several times the width of the teeth of the dressing tool to sweep across the width of the tool to be dressed.

[0012] b) Use the tools that have been prepared in this way to finish the workpiece.

[0013] According to the present invention, in this method, the axis crossing angle Σ is determined before performing work step a). A .

[0014] After it is determined, the previously set axis cross angle Σ A It remains unchanged during the tool finishing process (work step a).

[0015] Then, the tooth surface deformation, especially the torsion portion, to be shaped onto the tool is generated solely by the movement of the dressing tool along the longitudinal axis (Z1) and the transverse axis (X1) of the workpiece.

[0016] Therefore, the method according to the invention allows for the manufacture of a modified portion, especially a torsion portion, on the tooth surface of an externally geared workpiece on a machine tool with a minimum number of motion axes, according to a predetermined plan.

[0017] Therefore, rotary drive devices are needed to rotate the dressing tool and the honing tool that engages with it at rotational speeds corresponding to the gear ratio of the dressing tool and the tool, around the corresponding tool rotation axis E1 and the workpiece rotation axis (dresser) C1.

[0018] In addition, only an adjustment device is needed to adjust the workpiece in the longitudinal direction Z1, which is oriented parallel to the workpiece rotation axis C1, and in the transverse direction X1, which is transverse to its orientation, to shape the corresponding tooth surface deformation part, especially the torsion part, onto the tool.

[0019] Conversely, in the method according to the invention, the axis crossing angle does not change during machining.

[0020] Therefore, there is no need for an adjustment device capable of continuously adjusting the axis cross angle, which is still considered necessary in the prior art explained at the beginning.

[0021] Instead, for the method according to the invention, it is sufficient to set the shaft crossing angle suitable for the finishing process once before the finishing process. For this purpose, an adjustment device known in the prior art and inexpensive to implement can be provided.

[0022] The method according to the invention is also applicable to producing tooth surface deformation portions, especially torsional portions, of workpieces having straight or helical teeth. In internally toothed workpieces with straight teeth and corresponding externally toothed tools, the adjustment along the workpiece's transverse axis X1 performed during the dressing process according to the invention is limited to the path necessary for shaping the torsional portion. In internally toothed workpieces with straight teeth and corresponding externally toothed tools, in addition to the adjustment along the workpiece's transverse axis X1 performed during the dressing process for shaping the torsional portion according to the invention, there is an additional rotational adjustment of the dressing tool about the workpiece's rotation axis C1, performed in a known manner for this purpose. This is necessary for dressing tools that are narrowly guided along the bevel (Steigung) of the tool to be dressed.

[0023] Therefore, in the method according to the invention, during the dressing process (working step a), due to the additional movement of the dresser in the direction of the workpiece transverse axis X1, a deviation occurs on the honing tool, which is reflected as a shape deviation extending across the width of the honing tool.

[0024] These intentional deviations are transmitted to the teeth of the internally geared workpiece during subsequent workpiece machining, and can be identified as the desired tooth surface deformations on the tooth surface of the workpiece.

[0025] Here, the method according to the invention is particularly suitable for generating torsional portions on tooth surfaces. By correspondingly setting the axial movements along the longitudinal axis Z1 and the transverse axis X1 of the workpiece, the size and geometric features of the torsional portion can be precisely set in a simple manner.

[0026] When it is mentioned here that the dressing tool used according to the invention should be as narrow as possible, this means that its width is optimally reduced such that the tooth surface it assigns to the tooth face of the tool to be dressed is designed in a cutting edge manner or is at least narrow enough that there is only a minimal overlap between the tooth face of the dressing tool and the tooth face of the tool to be processed. Therefore, an advantageous design of the invention specifies that the width of the teeth of the dressing tool meshing with the honing tool to be dressed corresponds to at most one-fifth, preferably at most one-eighth, of the width of the tool to be dressed. Thus, according to the invention, the tool enters a tooth gap defined by the corresponding tooth face to be modified on one end face of a workpiece, and then moves along the corresponding tooth face in the Z direction until it exits the tooth gap again from the end corresponding to the other end face of the workpiece.

[0027] Specifically, trimming tools with a maximum width of 6 mm, particularly a maximum of 4 mm, a maximum of 2.5 mm, or a maximum of 1.2 mm are suitable for the purposes of the invention, wherein a width of at least 0.5 mm may be particularly practical in consideration of the stability of the trimming tool.

[0028] For example, the width of the teeth of an internal gear workpiece is measured parallel to the workpiece's axis of rotation. The width of the wheel-shaped dressing tool used according to the present invention is also measured parallel to the axis of rotation of the dressing tool.

[0029] The annular dressing tool with internal teeth, as described in DE 10 2017 104 625A1, is particularly suitable for implementing the method according to the invention. Attached Figure Description

[0030] The invention will now be explained in more detail with reference to the accompanying drawings, which illustrate embodiments. The drawings schematically show:

[0031] Figure 1 A front view of a machine tool used for honing the internal teeth of internally geared gears is shown;

[0032] Figure 2 A perspective view of the tooth surface of an internally geared gear is shown;

[0033] Figure 3a A front view of a tool used for dressing or milling external gear honing tools is shown;

[0034] Figure 3b It shows according to Figure 3a tool along Figure 3a A cross-sectional view of section line AA drawn in the middle;

[0035] Figure 4 The movement of the dressing tool during dressing is shown in the process according to the method of the invention.

[0036] Neither the space allocation nor the width ratio is represented proportionally in the drawing. Detailed Implementation

[0037] A traditionally designed machine tool 1 includes a workpiece spindle 2 and a tool spindle 3.

[0038] The workpiece spindle 2 is equipped with a receiving part 4 for the corresponding internally geared workpiece to be processed, and is coupled with a rotary drive device for rotating the workpiece around the workpiece rotation axis C1, an adjustment device for adjusting the workpiece spindle 2 along the workpiece longitudinal axis Z1 oriented parallel to the workpiece rotation axis C1, and an adjustment device for adjusting along the workpiece transverse axis X1 oriented transversely to the workpiece longitudinal axis Z1.

[0039] The tool spindle 3 is equipped with a housing 5 for externally toothed tool 6 and is coupled to a rotary drive for rotating tool 6 around tool rotation axis E1.

[0040] In addition, a setting for the axis cross angle Σ is provided. AIn device 7, the workpiece rotation axis C1 and the tool rotation axis E1 are oriented alternately with an intersecting angle, such that their projections on the drawing plane intersect each other, as shown below. Figure 4 As shown. For this purpose, the device 7 is designed in a known manner such that it enables the tool spindle 3 to pivot and be fixed relative to the pivot axis B1, which is oriented transversely to the tool rotation axis E1.

[0041] In order to adjust the tool spindle 3 relative to the plane enclosed by the longitudinal axis Z1 and the transverse axis X1 of the workpiece, an adjustment axis Y1 perpendicular to the plane can also be provided, but this is not necessary for implementing the method according to the invention.

[0042] Figure 2 The diagram illustrates the torsion portions to be generated on the tooth surfaces F1 and F2 of an internally toothed workpiece. The areas enclosed by solid lines represent the intentionally generated torsion portions FV1 and FV2, i.e., sections where the tooth surfaces F1 and F2, machined according to the invention, deviate from the standard shapes that do not contain torsion or other intentionally generated tooth surface deformations. These standard shapes of tooth surfaces F1 and F2 are... Figure 2 The middle part is represented by a dashed line.

[0043] Figure 3a and Figure 3b The structure of the annular trimming unit 11 shown is described in detail in the aforementioned DE 10 2017104 625A1, the contents of which are incorporated herein by reference. Therefore, the trimming unit 11 includes a support ring 12 formed of suitable steel, which surrounds a central longitudinal axis L and defines a support ring opening 13. The central longitudinal axis L is here concentrically oriented with the support ring opening 13.

[0044] In the edge region corresponding to the opening 13 of the support ring, a surrounding shoulder is formed starting from one end face 14 of the support ring 12. This surrounding shoulder forms a support element for the dressing tool 15, which is formed as a ring element and is therefore also referred to in practice as a "dressing wheel". It consists of multiple ring segments and is located on the support element and simultaneously close to the inner circumferential surface of the support ring 12 facing the support element.

[0045] The dressing tool 15 has an internal toothed portion 16 on its inner circumference corresponding to the support ring opening 13, which is formed by teeth 17 distributed at equal angular intervals around the center of the dressing tool 15. The teeth 17 of the internal toothed portion 16 extend freely from the edge of the support element facing the support ring opening 13, and have cutting edges 18 on their tooth surfaces and possibly also on their tooth tips, which are used to remove material from the honing tool 6 to be dressed during the dressing process.

[0046] The width D of the dressing tool 15, measured parallel to the longitudinal axis L, for example 3.2 mm, is significantly smaller than the width of the teeth of the outer teeth of the honing tool 6 to be processed. The dressing tool 15 is, for example, composed of synthetic diamond, which is applied as a cutting material layer onto a carrier layer preferably made of a hard metal. The dressing tool 15 is manufactured in a manner known per se, for example as described in EP 2036 675 B1 and WO 2011 / 157830 A1.

[0047] In order to dress the honing tool 6, the dressing unit 11 with the dressing tool 15 is placed in the receiving part of the workpiece spindle 2, and the corresponding workpiece to be processed is located in the receiving part during normal honing operation.

[0048] The tool rotation axis E1 and the workpiece rotation axis C1 intersect at an angle Σ. A The orientation of the axis cross angle corresponds unchanged to the axis cross angle in which the rotation axes E1 and C1 are oriented relative to each other during normal honing. However, if desired, an axis cross angle Σ can also be set that deviates from the axis cross angle set for honing. A If the axis cross angle Σ is set for the trimming process. A If the corresponding deviation settings help produce special variations in the shape of the tooth surfaces F1 and F2, then this may be the case. The decisive factor here is that once the shaft cross angle Σ is set... A It remains unchanged during the finishing process.

[0049] At the start of the dressing process, the dressing unit 11, rotating about the workpiece's rotation axis C1, is positioned adjacent to one end face of the honing tool 6, which rotates about the tool's rotation axis E1, with the dressing tool 15 in place. Then, the dressing unit 11 moves along the workpiece's longitudinal axis Z1 toward the honing tool 6 with the dressing tool 15 until the teeth 17 of the dressing tool 15 engage with the backlash of the honing tool 6, which has helical teeth, and the dressing tool 15 and the honing tool 6 begin to engage with each other. Simultaneously, the dressing tool 15 moves along the workpiece's transverse axis X1.

[0050] The movement along the transverse axis X1 of the workpiece varies in such a way that, depending on the torsion FV1, FV2 to be shaped, the cutting edge 18 of the tooth 17 of the dressing tool 15 that meshes with one of the teeth of the honing tool 6 removes more or less material from the corresponding machined tooth surfaces F1, F2.

[0051] Therefore, according to the present invention, a method is provided that allows for the generation of deformed portions, such as torsional portions FV1 and FV2, on the tooth surfaces F1 and F2 of an internally toothed workpiece using an externally toothed tool 6 on a machine tool 1, the machine tool having a reduced number of adjustable axes. To this end, the present invention specifies that the tool 6 can be dressed by arranging an internally toothed dressing tool 15 on the workpiece spindle 2 of the machine tool 1 at a position set for the corresponding workpiece to be honed, and by engaging the dressing tool 15 with the tool 6 to be dressed. The width of the teeth 17 of the dressing tool 15 is here smaller than the width of the tool 6 to be dressed, therefore the dressing tool 15 must be moved along the longitudinal axis Z1 of the workpiece by a distance corresponding to several times the width D of the teeth of the dressing tool 15. The workpiece 6 is then finished using the tool 1 dressed in this manner. According to the present invention, an axis cross angle Σ is set for dressing. A During the dressing process, the cross angle of the axis remains unchanged. Then, during the dressing process, the corresponding tooth surface deformation parts FV1 and FV2 are generated on the workpiece 6 by the movement of the dressing tool 15 along the tool longitudinal axis Z1 and the tool transverse axis X1.

[0052] Explanation of reference numerals in the attached figures

[0053] 1 Machine tool

[0054] 2. Workpiece spindle

[0055] 3. Tool Spindle

[0056] 4. Reception section for internal geared workpieces to be machined

[0057] 5 Receiving part for external honing tool 6

[0058] 6 Honing tools

[0059] 7 is used to set the axis cross angle Σ A device

[0060] 11. Circular trimming unit (see DE 10 2017 104 625 A1)

[0061] 12 Support rings

[0062] 13. Support ring opening

[0063] 14. End face of support ring 12

[0064] 15. Repair tools

[0065] 16. Internal teeth of dressing tool 15

[0066] 17. Trimming tool with 15 teeth

[0067] 18 teeth, 17 cutting edge

[0068] B1 Pivot axis of tool spindle 3

[0069] C1 Workpiece rotation axis

[0070] D. Width of trimming tool 15

[0071] E1 Tool Rotation Axis

[0072] The tooth surfaces of F1 and F2 internally toothed workpieces

[0073] FV1, FV2 torsion section

[0074] L-shaped trimming unit 11's central longitudinal axis

[0075] X1 Workpiece transverse axis

[0076] Y1 tool spindle 3 adjustment axis

[0077] Z1 Workpiece longitudinal axis

[0078] Σ A Axis Cross Angle

Claims

1. A method for producing deformed portions (FV1, FV2) on the tooth surfaces (F1, F2) of an internally toothed workpiece using an externally toothed tool (6) on a machine tool (1), wherein the teeth of the externally toothed tool mesh with the teeth of the workpiece during honing, the machine tool comprising a workpiece spindle (2) having a rotary drive for rotating the workpiece about a workpiece rotation axis (C1), an adjustment device for adjusting the workpiece along a workpiece longitudinal axis (Z1) oriented parallel to the workpiece rotation axis (C1), an adjustment device for adjusting the workpiece along a workpiece transverse axis (X1) oriented transversely to the workpiece longitudinal axis (Z1), a tool spindle (3) having a rotary drive for rotating the tool (6) about a tool rotation axis (E1), and a method for setting an axis cross angle (Σ). A The apparatus (7) wherein the workpiece rotation axis (C1) and the tool rotation axis (E1) are oriented alternately to each other at the axis crossing angle during honing, the method comprising the following steps: a) The tool (6) is dressed by arranging an internally toothed dressing tool (15) on the workpiece spindle (2) at a position set for the corresponding workpiece to be honed and by engaging the dressing tool (15) with the tool (6) to be dressed, wherein the width (D) of the teeth (17) of the dressing tool (15) that mesh with the tool (6) to be dressed is smaller than the width of the tool (6) to be dressed, such that the dressing tool (15) must move a distance along the longitudinal axis (Z1) of the workpiece corresponding to several times the width of the teeth of the dressing tool (15) to sweep across the width of the tool (6) to be dressed. b) Use the tool (6) prepared in this way to finish the workpiece. Its features are, Determine the axis cross angle (Σ) before performing work step a). A ), the previously set axis cross angle (Σ) A The tooth surfaces (F1, F2) remain unchanged during the execution of work step a), and the modified parts (FV1, FV2) are generated only by the movement of the dressing tool (15) along the longitudinal axis (Z1) and the transverse axis (X1) of the workpiece.

2. The method according to claim 1, characterized in that, The maximum width of the trimming tool (15) is 6 mm.

3. The method according to claim 2, characterized in that, The maximum width (D) of the trimming tool (15) is 2.5 mm.

4. The method according to any one of the preceding claims, characterized in that, The width (D) of the trimming tool (15) is at least 0.5 mm.

5. The method according to claim 1, characterized in that, The deformed part is a torsion part.

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