Method for Machining the Tip Circle Diameter and a Tool for Producing a Gearwheel

Abstract

The invention relates to a method for machining the tip circle diameter of a tooth system (4) of a gearwheel (6), in which the gearwheel (6) rotates about a workpiece axis of rotation (Rw), and in which at least one tooth (9) of the tooth system (4) is machined, by removing chips, by means of a tool (7, 7′) that rotates about a tool axis of rotation (Rz) oriented at an axial distance (A′, A″) relative to the workpiece axis of rotation (Rw). According to the invention, the tool (7, 7′) is disk-shaped, the disk-shaped tool (7, 7′) machines the tip surface (8) of the tooth (9), by removing chips, with at least one partial segment (10a) of its circumferential edge configured as a defined blade (10), wherein a relative movement between the tool (7, 7′) and the gearwheel (6), oriented in the axial direction of the tooth system (4), is carried out during the chip-removing machining, as a consequence of which movement the tool (7, 7′) sweeps over the tip surface (8), and the tool axis of rotation (Rz) is oriented at an axis intersection angle (Σ″) of 5° to 40° with respect to the workpiece axis of rotation (Rw). In this way, efficient and highly precise machining of the tip circle diameter is made possible. The invention also states a method for producing a gearwheel, in which the tooth system (4) is produced on a gearwheel blank (5) by means of hob peeling before machining of the tip circle diameter according to the invention, as well as a combination tool, in which a hob-peeling wheel for producing the gearwheel and a disk-shaped tool for machining the tip circle diameter according to the invention are combined with each other.

Claims

1. A method for machining the tip circle diameter of a tooth system of a gearwheel, in which the gearwheel provided with the tooth system is driven to rotate about a workpiece axis of rotation (Rw) and in which at least one tooth of the tooth system of the gearwheel is machined by means of a tool, by removing chips, which tool rotates about a tool axis of rotation (Rz) oriented at an axial distance (A′, A″) from the workpiece axis of rotation (Rw), characterized in that the tool is disk-shaped, that the disk-shaped tool machines the tip surface of the tooth to be machined, in each instance, by removing chips, using at least one partial segment of its circumferential edge configured as a defined blade, that a relative movement between the tool and the gearwheel is performed during the chip-removing machining, which movement is oriented in the axial direction of the tooth system, and as the result of which movement the tool sweeps over the tip surface to be machined, and that the tool axis of rotation (Rz) is oriented, with respect to the workpiece axis of rotation (Rw), at an axis intersection angle (Σ″) of 5° to 40°.

2. The method according to claim 1, characterized in that the relative movement performed during the chip-removing movement is brought about in that the disk-shaped tool) is moved axially along the tool axis of rotation (Rz), from a starting position, which is assigned to a first end face of the gearwheel, in the direction of the second end face of the gearwheel.

3. The method according to claim 1, characterized in that the relative movement performed during the chip-removing movement is brought about in that the gearwheel is moved axially along the workpiece axis of rotation (Rw) from a starting position, which is assigned to a first end face of the disk-shaped tool, in the direction of the second end face of the disk-shaped tool.

4. The method according to claim 1, characterized in that the axis intersection angle (Σ″) is at least 10°.

5. The method according to claim 1, characterized in that the axis intersection angle (Σ″) is at most 35°.

6. The method according to claim 1, characterized in that the circumferential edge of the tool is configured as a defined blade over its entire circumference length.

7. The method according to claim 1, characterized in that partial segments of the circumferential edge are configured as a defined blade, distributed over the circumference of the circumferential edge, in each instance.

8. The method according to claim 1, characterized in that during the chip-removing machining, the speed of rotation ratio Wz/Ww formed from the speed of rotation Wz of the disk-shaped tool and the speed of rotation Ww of the workpiece is 1.1 to 10.

9. The method according to claim 8, characterized in that the speed of rotation ratio Wz/Ww is 1.1 to 5.

10. The method according to claim 1, characterized in that the disk-shaped tool and the workpiece rotate in the same direction during the chip-removing machining.

11. The method according to claim 1, characterized in that the disk-shaped tool has a thickness (Dz), measured axis-parallel to the tool axis of rotation (Rz), of at least 1 mm.

12. The method according to claim 1, characterized in that provision is made of a gearwheel blank, on which the tooth system is produced by means of hob peeling, on which system machining of the tip surface of the at least one tooth is subsequently carried out by means of the disk-shaped tool.

13. The method according to claim 12, characterized in that a hob-peeling tool for producing the tooth system and the disk-shaped tool for chip-removing machining of the tip surface are jointly attached to a tool holder, offset from one another in the axis direction (Xz) of the tool axis of rotation (Rz).

14. The method according to claim 12, characterized in that the axis intersection angle (Σ′) set during the hob-peeling machining carried out for producing the tooth system differs from the axis intersection angle (Σ″) at which the tool axis of rotation (Rz) is oriented during the chip-removing machining of the workpiece by means of the disk-shaped tool, with respect to the axis of rotation (Rw) of the workpiece.

15. A combination tool for producing a gearwheel, characterized in that it comprises a tool holder on which a hob-peeling tool for producing a tooth system on a gearwheel blank and a disk-shaped tool for machining the tip surface of at least one tooth of the tooth system produced with the hob-peeling tool are arranged spaced apart from one another in the axis direction of the tool holder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In the following, the invention will be explained in greater detail using a drawing that shows an exemplary embodiment. The figures schematically show:

[0028] FIG. 1 a perspective view of a combination tool for producing an internal tooth system on a gearwheel blank and subsequent machining of the tip circle diameter of the internal tooth system;

[0029] FIG. 2 a perspective view of a gearwheel-shaped hob-peeling tool, which is part of the combination tool according to FIG. 1, during machining of the gearwheel blank for producing the internal tooth system, in which the other components of the combination tool have been left out;

[0030] FIG. 3 a perspective view of a disk-shaped tool, which is part of the combination tool according to FIG. 1, during machining of the tip surfaces of the internal tooth system, in which the other components of the combination tool have been left out;

[0031] FIG. 4 a perspective view of an alternative design of the disk-shaped tool according to FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The combination tool 1 comprises a tool holder 2, formed in the manner of a bearing axle, which is coupled to the rotary drive (not shown) of a conventional machine tool (also not shown) designed for hob-peeling machining, and which is driven to rotate about its axis of rotation Rz in this manner at a speed of rotation Wz.

[0033] The tool holder 2 of the combination tool 1 bears a gearwheel-shaped hob-peeling wheel 3 at its front free end, which wheel is designed, in a conventional manner, for producing an internal tooth system 4 on a gearwheel 6, which is initially provided as a gearwheel blank 5 (FIG. 2).

[0034] In the axis direction Xz of the tool holder 2, offset relative to the hob-peeling wheel 3 in the direction of the chuck of the tool holder 2, a disk-shaped tool 7 is fastened to the tool holder 2 as a further element of the combination tool 1, which tool is oriented coaxial to the axis of rotation Rz of the tool holder 2 and has a thickness Dz of 6 mm, for example.

[0035] The disk-shaped tool 7 serves for machining the tip surfaces 8 of the teeth 9 of the internal tooth system 4 of the gearwheel 6, which were produced by the hob-peeling wheel 3. For this purpose, the tool 7 has a defined cutting edge 10, which runs around its front end face 11 relative to the hob-peeling wheel 3.

[0036] To produce the gearwheel 6, the gearwheel blank 5 is clamped into a workpiece chuck 12 of the machine tool (not shown here).

[0037] The gearwheel blank 5 is preferably provided without teeth, but can also be provided, in a manner known per se, with a pre-finished rough internal tooth system, which is now machined to finish it, by means of the hob-peeling wheel 3, by removing chips, in terms of the geometry of its teeth 9.

[0038] The gearwheel blank 5 to be provided with the internal tooth system 4 is driven to rotate, in a known manner, by means of a not shown rotary drive of the machine tool about a workpiece axis of rotation Rw, at a workpiece speed of rotation Ww, in the same direction as the rotation of the hob-peeling wheel 3. In this regard, the speed of rotation ratio Wz/Ww formed from the workpiece speed of rotation Ww and the tool speed of rotation Wz is 3:1, for example.

[0039] During the hob-peeling machining of the teeth 9 of the gearwheel blank 5 by means of the hob-peeling wheel 3, which now follows, the workpiece axis of rotation Rw is oriented at an axis intersection angle Σ′, which is 20°, for example, and at an axial distance A′ with respect to the tool axis Rz. Accordingly, the hob-peeling wheel 3 is at first situated, at the beginning of machining, in the axial direction, on the side of the gearwheel blank 5 that is assigned to the chuck of the tool holder 2, outside of the internal tooth system 4. The gearwheel blank 5 is then displaced in the axial direction Xw, along the workpiece axis Rw, relative to the hob-peeling wheel 3, which is at rest relative to the axis direction of its axis of rotation Rz so that the internal tooth system 4 is moved along the hob-peeling wheel 3 until the hob-peeling wheel 3 exits from the internal tooth system 4 on the opposite side of the gearwheel blank 5.

[0040] Because of the relative movement that occurs as the result of the axis intersection angle Σ′ and the axial movement in the axis direction Xz between the teeth 9 of the hob-peeling wheel 3 and the internal tooth system 4 that come into contact with one another, chip removal takes place during this process in a manner known per se, by means of which removal the teeth 9 of the internal tooth system 4 are shaped in final form in the region of their tooth flanks. The hob-peeling machining of the internal tooth system 4 using the hob-peeling wheel 3 is continued until all teeth 9 of the internal tooth system 4 have been shaped in final form in accordance with the default values that apply to this work step.

[0041] After production of the internal tooth system 4 of the gearwheel 6 by means of the hob-peeling wheel 3 has been completed, the tool holder 2, with the hob-peeling wheel 3 and the disk-shaped tool 7, is oriented by means of a movement of the tool holder 2 and/or of the gearwheel 6 in the axial direction Xz such that the tool 7 is arranged close to the end face 6a of the gearwheel 6 that faces the chuck of the tool holder 2.

[0042] Furthermore, the tool holder 2 is pivoted in such a manner that the tool axis of rotation Rz is oriented with respect to the workpiece axis of rotation Rw at an axis intersection angle Σ″ that deviates from the axis intersection angle Σ′ and is 10°, for example. Likewise, an axial distance A″ is set between the workpiece axis of rotation Rw and the tool axis of rotation Rz, which distance is dimensioned in such a manner that the cutting edge 10 of the disk-shaped tool 7 is arranged offset, in the radial direction, by the desired chip depth S relative to the tip surfaces 8 of the teeth 9 of the internal tooth system 4, in the direction of the outside circumference of the gearwheel 6.

[0043] For the subsequent machining of the tip circle diameter, the disk-shaped tool 7 also rotates in the same direction as the direction of rotation Ww of the gearwheel 6, at a speed of rotation Wz, about its tool axis Rz. The speed of rotation ratio Wz/Ww formed from the workpiece speed of rotation Ww and the tool speed of rotation Wz is now 2:1, for example.

[0044] The gearwheel-shaped hob-peeling wheel 3 is moved by means of the gearwheel 6 in the axial direction Xz over the width B of the tip surfaces 8 until its cutting edge 10 has entirely swept over the tip surfaces 8 of the teeth 9, and has removed a chip having the thickness S from the tip surfaces 8 while doing so. This process is repeated until all tip surfaces 8 of the teeth 9 of the internal tooth system 4 have been machined in a corresponding manner, and the required tip circle diameter of the internal tooth system 4 has been achieved.

[0045] In FIG. 4, a disk-shaped tool 7′ is shown as a variant of the disk-shaped tool 7 used, according to the invention, for machining the tip circle diameter; its cutting edge 10′, which runs around its front end face 11′, is segmented such that cutting edge segments 10a follow free spaces 10b at regular intervals and regular angle distances. If the disk-shaped tool 7′ is mounted on the tool holder 2 of the combination tool 1 in place of the disk-shaped tool 7 and used for machining the tip circle diameter in the manner described above, then only the tip surfaces 8 of the teeth 9 of the internal tooth system 4 are machined, by removing chips, which surfaces are arranged in accordance with the distances between the cutting edge segments 10, taking into consideration the corresponding speed of rotation ratio Wz/Ww. In this way, machining of the tip circle diameter can be restricted to only every other or every third tooth 9 of the internal tooth system 4, for example, while the other teeth 9 remain unshortened.

REFERENCE SYMBOLS

[0046] 1 combination tool [0047] 2 tool holder of the combination tool 1 [0048] 3 gearwheel-shaped hob-peeling wheel [0049] 4 internal tooth system of the gearwheel 6 [0050] 5 gearwheel blank [0051] 6 gearwheel [0052] 6a end face of the gearwheel 6, facing the chuck of the tool holder 2 [0053] 7, 7′ disk-shaped tool [0054] 8 tip surfaces of the teeth 9 of the internal tooth system 4 [0055] 9 teeth of the internal tooth system 4 [0056] 10, 10′ cutting edge of the tool 7, 7′ [0057] 10a cutting edge segments of the disk-shaped tool 7′ [0058] 10b free spaces of the cutting edge 10′ of the disk-shaped tool 7′ [0059] 11, 11′ front end face of the disk-shaped tool 7, 7′ [0060] 12 workpiece chuck [0061] A′, A″ axial distance [0062] B width of the tip surfaces 8 [0063] Dz thickness of the disk-shaped tool [0064] Rw workpiece axis of rotation [0065] Rz axis of rotation Rz of the combination tool 1 and of its hob-peeling wheel 3 as well as of the disk-shaped tool 7 [0066] S chip depth [0067] Ww workpiece speed of rotation [0068] Wz respective speeds of rotation of the combination tool 1 and of its hob-peeling wheel 3 as well as of the disk-shaped tool 7 [0069] Xz axis direction of the tool axis of rotation Rz [0070] Xw axis direction of the workpiece axis of rotation Rw [0071] Σ′, Σ″, axis intersection angle