WO2019161823A1

WO2019161823A1 - Method and device for chamfering toothed workpieces

Info

Publication number: WO2019161823A1
Application number: PCT/DE2019/000040
Authority: WO
Inventors: Joerg Lohmann
Original assignee: EMAG GmbH & Co. KG
Priority date: 2018-02-21
Filing date: 2019-02-20
Publication date: 2019-08-29
Also published as: DE102018001389A1

Abstract

The invention relates to a method and a device for chamfering and deburring gears (1) from the front, comprising a chamfering tool (2) having at least one tool blade (3), which is designed as a cutting plate, with at least one cutting edge (4), wherein at least one chamfering tool (2) designed as a chamfering cutter passes tangentially through the toothing of the work gear (1).

Description

Method and device for chamfering toothed workpieces

The invention relates to a method and a device for frontally chamfering toothed workpieces according to the preamble of patent claim 1 and claim 6.

From EP 1 495 824 B1 it has become known to dive with a deburring tool similar to a side-milling cutter between the tooth flanks of two adjacent teeth of a workpiece. At the deburring tool teeth are arranged one behind the other in the circumferential direction, the tooth faces are used as clamping surfaces, wherein the clamping surfaces are aligned substantially parallel to the tool axis. This procedure has also become known by the term "Chamfer Cut".

The invention has for its object to further develop the processing of gears useful advantage. The object is achieved by a method according to the invention according to claim 1 and a device according to the invention according to claim 6. Advantageous developments are subject of the dependent claims.

The method according to the invention as well as the device according to the invention has a chamfering tool configured as a chamfering cutter which moves tangentially through the toothing of the work wheel. It is advantageous by means of the present invention that the cycle time for the production of chamfers on teeth and / or deburring of gears can be significantly shortened.

In a further advantageous embodiment measuring devices are provided by means of which the manufacturing quality of the workpieces can be monitored parallel to the main time. If necessary, the angular position of the workpieces can be detected with sensors.

Further advantages of the method according to the invention:

1. Universal tool profiles:

By means of the above-described kinematics according to the invention and the design of the tool, workpieces of the same module with different numbers of teeth can be chamfered with one and the same tool profile. In contrast, the Chamfer Cut process requires a tailor-made tool for each individual tooth or number of teeth.

1

confirmation copy 2. Design of the chamfer by Hüllschnitte

Thanks to the kinematics, the chamfer profile is produced in this method according to the invention by overlapping envelopes. Due to the setting angle Eta and the design of the tangential feed, the design of the chamfer can be influenced without requiring, for example, a logistically and costly complicated adaptation or modification of the profile (re-profiling) of the tool.

In addition, the cutting work is divided into several small chip cross sections. Each tooth performs a different envelope cut and thus a good distribution of the cutting load is achieved and thus a very good wear behavior is expected.

In contrast, the Chamfer-Cut process requires multiple workpiece rotations, with the single cutting edge always cutting exactly the same cross-section. Needle chips, which are more difficult to filter, are also a major disadvantage.

3. Reduction of tool costs

The simple design of the tool 1 cheap disc cutters, or even Schlagzahnkassetten and thus replaceable percussion teeth can be used. The production of such tools is much cheaper and also given the reusability in an advantageous manner.

4. Increase productivity

Especially the use of percussion teeth advantageously allows the use of carbide, CBN, cermet and other high-performance cutting materials that (as of today) are not yet used in chamfering. This allows higher stalls, but also higher cutting speeds and thus shorter cycle times than usual today.

Of importance is that it is a continuous process for deburring, or more precisely for chamfering straight or helical serrations. In this case, along the contour of the toothing edge chipping by machining shaping (milling) attached. The invention will be described in more detail below with reference to an exemplary embodiment.

Show it:

Fig. 1 shows an embodiment of the chamfering tool.

Fig. 2 shows the engagement of the chamfering tool 2 on the gear / gear. 1

Fig. 3, the chamfering tool 2 in engagement with the work gear / gear 1, wherein the chamfering tool 2 is inclined by an adjustment angle Eta.

Fig. 4, the chamfering tool 2 in engagement with the work gear / gear 1, wherein the chamfering tool 2 is inclined by an adjustment angle Eta. The Anfaswerkzeug designed as Anfasfräser 2 moves tangentially through the teeth of the

Werkrades 1 through (see in plan view). Optionally, the

Change the swing angle Eta with continuous tangential path.

5 shows a device or machine tool for carrying out the

inventive method.

Fig. 6 Tool profile before and after the transformation.

7 shows the Denavit-Hartenberg matrix for the conversion of the profile coordinates.

In Fig. 2 and Fig. 4, the engagement of the chamfering tool 2 on the gear 1 is shown. The gear wheel 1 is drivable about a rotation axis 8 'and the chamfering tool 2 about a rotation axis 8. The rotation axes 8, 8' of the chamfering tool 2 and the gear wheel 1 can be arranged skewed relative to one another and can over

Acoustic coupling in a fixed speed ratio to each other are set in rotation (see Fig. 5). The chamfering tool 2 has at least one on one

Circumferentially arranged cutting edge 3 on. In order to deburr the gears 1 at the top and bottom in one clamping, a second Anfaswerkzaug 2 'with at least one other cutting edge 3' is provided which rotates opposite to the direction of rotation of the first Anfaswerkzeug 2 or whose at least one tool cutting edge 3 opposite is aligned with the direction of rotation of the first chamfering tool 2. The processing is done by a comparable with hobbing rolling off, the active site between

Tool cutting edge 3, 3 'and end edge 5 during chamfering along the cutting edge 4 moves.

Advantageously, the end edges of any teeth can be chamfered with the device. For adaptation to others, only the tool cutting edges 3, 3 'are to be exchanged.

Fig. 5 shows a hobbing machine or a separate chamfering device, wherein in the machining of helical gears, the tool 1 the

Helix angle of the toothing is inclined or pivoted in accordance with the axis A. For this purpose is - not shown - the Machining head, which carries the tools 1 or a tool holder or tool receiving mandrel receiving the tools 1, by means of

at least one drive about a pivot axis pivotable.

In this method according to the invention, a disk-shaped cutting tool is used. This may be, for example, a disc milling cutter or a form milling cutter or an impact tooth cassette which has at least one or more cutting edges or at least one mounted impaction tooth or a plurality.

In the case of percussion teeth, it is particularly advantageous in terms of tooling costs to make them reusable for reuse like an indexable insert.

This tool 2 is placed at a certain angle (for example, below 45 degrees) to the toothing to be tapped the work wheel 1 (see Fig. 2). If necessary, an adjustment of the jig is required to avoid a potential collision. The tool 2 has, for example, four blades 3 (see FIG. 1).

In principle, as shown in FIG. 5, two tools 2, 2 'are used whose cutting directions are in opposite directions. Thus, first one side and then, after the shift to the second tool 2 ^' and after the inversion of the cutting direction, the second side of the work wheel 1 chamfered. The shaving is disclosed in detail in our earlier application DE 10 2015 012 908, which is why a further description is omitted here. In addition, the following claims and the advantages shown clearly illustrate the present invention.

In order to determine the profile of the tool 2, one first draws the reference profile of the hob, with which the work gear 1 was originally toothed (eg DIN 3972 reference profile II). This hob cutter profile is now transformed on the basis of a rotation matrix so that the new engagement situation, ie the setting of the tool at a certain angle, here for example 45 degrees (see FIG. 2), is taken into account. One way of determining this profile is the transformation using a Denavit-Hartenberg matrix (see Figures 6 and 7). This has the advantage that additional rotational rotations in other axes and translational displacements can be carried out simultaneously, and thus also the helix angle in the case of helical gearing can be taken into account.

The cutting edges or cutter teeth 3 of the tool 2 or - not shown in detail - the impact teeth of the impaction tooth cassette are profiled according to the transformed profile and additionally attached a clearance angle along the profile.

Of course, depending on the desired chamfer geometry, various profile modifications are possible. For example, head edge fractures, flank allowances, protuberances, high-level crowns or the like. be taken into account.

Process kinematics & machining cycle:

The work gear 1 and the chamfering tool configured as a chamfer 2 rotate in the speed ratio of their numbers of teeth.

That means specifically:

For clarification "Z tool" corresponds to the number of cutting edges of the tool.

This ensures that each tool tooth meets in the subsequent tooth gap of the work gear. Compare also when hobbing the use of a two-speed hob, for example, where the second gear always meets the gap that follows the gap cut by the first gear.

To allow the cutting tool better cutting conditions, the milling tool can be inclined by an adjustment angle Eta (see Fig. 3). This is calculated as: h = arctan

It is advantageous with regard to secondary ridge formation to select the cutting direction into the workpiece 1. So you can make use of the flat cutting exit angle in the teeth and avoids secondary burrs.

The Anfaswerkzeug 2 is placed at the beginning of the processing cycle to final milling depth 1 1 in the Zustellachse Z. Under continuous rotation of the coupled axes, the tool 2 moves in a tangential feed 12 relative to the work gear 1 in the teeth to be tapped 13 (see Fig. 4).

Depending on the design of the machine, additional Z-axis interpolation may be required in order to be able to drive the tangential feed 12 relative to the work wheel 1, since otherwise the tool 2 will retract into the workpiece 1 only in its axial direction and thus diagonally in relation to the workpiece axis would. The setting angle Eta remains constant.

Optionally, the clipping result, i. Angle and bevel shape, and also the cutting conditions are influenced by an additional change of the setting angle Eta. This can be influenced via the swivel axis of the chamfering device (A-axis of the machine). This pivotal movement of the tool is superimposed on the tangential feed. As a result, the setting angle Eta of the tool changes with continuous tangential path. In addition, if necessary, an interpolation in the Z-axis can take place simultaneously. The pivot angle reaches its "relative zero point" when the tool 2 is orthogonal to the vertical Werkradachse 7.

As shown in Fig. 4, the angle Eta with continuous tangential feed can vary by +/- 10 degrees from the "base angle Eta", which is preferably 6 degrees, that is from 16 degrees to -4 degrees.

Another possibility of influencing the chamfering is to drive the tangentiaivorschub intermittently or bring a continuously changing offset in the coupling ratio of the rotary axes.

After the exit of the tool from the workpiece 1 in the tangential direction, the machining is completed on one side. It is shifted to the second tool 2 'with opposite cutting direction, the cutting direction inverted and the second side of the gear in the same process chamfered (see Fig. 5). The tools 1 for both sides of the workpiece can - not shown in detail - are mounted next to the gear hob for the production of the teeth of the work wheel 1 on the same milling mandrel and come on a hobbing machine used. Alternatively, the method can also be used on a separate chamfering machine or a device integrated in the gear cutting machine.

Ideally, the distance between the two Anfaswerkzeuge 2 on the tool holder mandrel to each other selected such that the tool 2 with the direction of rotation reversed cutting direction (which is currently not in use), runs empty through the existing tooth gaps of the work gear 1, while the other tool 2 straight in Intervention is. In this way, the required Shiftweg, performed by the Y-axis of the machine tool, can be reduced advantageously.

In an alternative embodiment, the chamfering tool 2 can be provided with at least two cutting tools 3, 3 '.

In a further embodiment, the upper and lower sides of the work wheels 1 or toothed wheels 1 are each assigned at least one chamfering tool 2, 2 '.

The cutting edges 4 of the tool cutting edges 3, 3 'can in one

be aligned according to different directions of rotation.

In the device according to the invention, the angle Eta with continuous tangential feed changes by +/- 10 degrees from the "base angle Eta", which is preferably in particular 6 degrees, that is to say preferably 16 degrees to -4 degrees.

LIST OF REFERENCE NUMBERS

1 workpiece / workpiece / gear

2 chamfering tool / tool

3 tool cutting edge

4 cutting edge

5 front edge

6 chamfer

7 rotation axis workwheel (C-axis)

8 Rotation axis Chamfering tool (B-axis) 9 Swiveling via A-axis

10 intervention sensor / measuring sensor for quality inspection

11 final milling depth

12 tangential feed

13 toothing

X X axis

Y Y-Ache

Z Z axis

Claims

claims

1. A method for the end-side chamfering and deburring of gears (1) with a Anfaswerkzeug (2) with at least one as an insert

executed tool cutting edge (3) with at least one cutting edge (4), wherein at least one Anfaswerkzeug configured as Anfasfräser (2) moves tangentially through the teeth of the work wheel (1) passes.

2. The method of claim 1, comprising the following method steps:

a) set the chamfering tool (2) to final milling depth (11) in the

Infeed axis (Z)

b) retracting the chamfering tool (2) with continuous rotation of the chamfering tool (2) and the work wheel (1) in a tangential feed (12) relative to the work gear (1) in the teeth (13) to be chamfered.

3. The method according to claim 2, characterized in that the

Chamfering tool (2) is set at the beginning of the processing cycle to the final milling depth (11).

4. The method according to claim 2 or 3, characterized in that the axes are coupled together.

5. The method according to any one of claims 1 to 4, characterized in that the angle Eta with continuous tangential feed to +/- 10 degrees from the "base angle Eta", which is preferably in particular 6 degrees, that is preferably in particular 16 degrees to -4 degrees will be changed.

6. The method according to any one of claims 1 to 5, characterized in that an interpolation of the Z-axis (Z) is performed.

7. An apparatus for end-side chamfering and deburring of gears (1) with a chamfering tool (2) with at least one as an insert

executed cutting tool (3) with at least one cutting edge (4), wherein at least one configured as chamfer chamfering tool (2) moves tangentially through the teeth of the work gear (1) passes.

8. Apparatus according to claim 7 for carrying out the method according to one of the claims 1 to 6, characterized in that the

Chamfering tool (2) is designed as a Schlagzahnkassette with at least one interchangeable impact tooth.

9. Device according to claim 8, characterized in that as

Impact tooth a tooth made of carbide, CBN, cermet and others

High performance cutting materials is used for chamfering.

10. Device according to one of the claims 7 to 9, characterized in that the top and bottom of the work wheels (1) or gears (1) at least one chamfering tool (2, 2 ') is assigned.