WO2017063730A1

WO2017063730A1 - Method for machining a toothing, and arrangement, machining tool, and machine tool for this purpose

Info

Publication number: WO2017063730A1
Application number: PCT/EP2016/001639
Authority: WO
Inventors: Karl Schäferling
Original assignee: Gleason-Pfauter Maschinenfabrik Gmbh
Priority date: 2015-10-16
Filing date: 2016-10-04
Publication date: 2017-04-20
Also published as: DE102015013497A1

Abstract

The invention relates to a method for machining a toothing (2) rotating about its toothing axis (C4), in which a secondary burr, occurring in an area close to the tooth front edge during chamfering of a tooth front edge of the toothing on a tooth flank of the toothing, is at least substantially removed by means of a rolling machining operation using a machining tool (7) rotating about a tool axis (C3), wherein the machining tool has at least one cutting edge which can perform a movement that removes the secondary burr in a cutting manner by providing an axis intersection angle (∑), not equal to zero, between the toothing axis and the tool axis in the machining operation.

Description

METHOD FOR MACHINING A GEARING AND ARRANGEMENT, MACHINING TOOL AND TOOLING MACHINE THEREFOR

The invention relates to the field of complementary tooth forming and more particularly to a method for machining a toothing axis rotating around its toothing axis, wherein a secondary ridge formed during chamfering of a toothed edge of the toothing on a tooth flank of the toothing in a region close to the tooth face is produced by a rolling machining engagement with a toothed edge at least for the most part eliminates about a tool axis rotating machining tool, as well as an arrangement suitable for carrying out this method.

Known manner arises in the cutting production of teeth, for example by hobbing, at the tooth front edges a burr that needs to be eliminated by way of complementary tooth formation for various reasons. For one, an end face of the gear in subsequent operations often as a planar clamping or Serve the intended area whose planarity is disturbed by the ridge. In addition, there is a risk that the ridge of the later hardened gear in use jumps when running in a transmission and causes damage to the tooth flanks or transmission components. Apart from that, such a burr also poses a risk of injury when handling the workpieces, and increases the risk of transport damage.

For these reasons, one provides the Zahnstirnkanten with a chamfer. A pictorial representation of teeth after hobbing and chamfering can be found in Figure 8.1 - 1, first row, columns 2, 3 on p. 4 of Thomas Bausch, Innovative gear production, 3rd edition.

One way to form the chamfer is a forming process in which, for example, a gear-shaped tool is brought to the tooth axis parallel tool axis in rolling machining engagement with the teeth to be tapped and forms the chamfer by plastic deformation. Such a method is described for example in EP 1 270 127 A1 and is also referred to as Wälzentgraten. In this plastic deformation, however, a so-called Sekundärgrat is raised in the edge region of the adjacent tooth flank. If the workpiece is designed for high gear precision and is therefore subjected to a hard / fine machining such as grinding or honing after the hardening process, this secondary burr must also be removed, otherwise it would lead to high wear of the hard machining tool.

To eliminate this secondary burr, for example, additional tools have been used in combination with the chamfering tool. For example, DE 10 2009 018 405 discloses a tool wheel which is non-rotatably connected to a toothed chamfering wheel which is coaxial therewith and has recesses extending essentially in the circumferential direction on the front side of its teeth and which can lie in the end section on one or more circular arcs or the course of a spiral, when used, rolling occurs in the tooth height direction of the workpiece. More clearly, however, is the combination tool shown in the above-mentioned reference Bausch on page 309 in Figure 8.2-5, which consists in its basic version of two Wälzentgraträdern and a spacer and in which next to a deburring also a smoothing area is provided, the secondary ridge smoothed by pressing, see also EP 1 270 127 A1. With the advent of the so-called double-spindle machines in which two workpiece spindles are arranged on a rotary holder such that a workpiece spindle is in a machining position for the hobbing and the other workpiece spindle in the machining position for chamfering and vice versa by 180 ° rotation of the rotary holder the problem of secondary ridge removal has been solved in such a way that after being chamfered, the swivel holder again spins the chamfered workpiece into the hobbing position and the hob cuts off the secondary ridges on the workpiece tooth flanks in a second cut. This is described in EP 2 066 473 B1.

Since all the aforementioned methods for secondary deburring are associated with considerable effort, methods are also used in which the bevel is produced by cutting the toothed end edges, as disclosed for example in DE 0 2009 019 433 A1.

The invention has for its object to simplify a method of the type mentioned while maintaining a satisfactory processing quality.

This object is achieved in procedural terms by a development of the method of the type mentioned above, which is characterized essentially in that the machining tool has at least one cutting edge, which is provided by providing a non-zero axis crossing angle between the toothing axis and the tool axis in the machining engagement making the secondary ridge cutting away erosive movement.

In the context of the invention, it has been recognized that a cutting removal of the secondary burr, which is considered to be superior to a smooth rolling of the secondary burr, can be achieved with a simple tool design with good processing results by the invention provided by non-zero axis cross angle between the tooth axis and the tool axis.

In a particularly preferred embodiment, the Sekundärgrat on the other tooth flank side is at least for the most part eliminated, in particular in the same processing engagement and / or in particular the same machining tool, This allows shorter processing times for the Sekundärgratbeseitigung. Preferably, the secondary burr is removed on both sides not only for the most part but also completely, but a removal can already for the most part already sufficient to significantly reduce the stresses on a hardening hard / finish hard / finish tool.

In a particularly preferred embodiment, no cutting machining takes place in the area of the tooth flank centered with respect to the toothing axis during the machining engagement. In this way, for some hard / finishing processes, e.g. for honing desired Fräsvorschubmarkierungen remain on the workpiece.

In a particularly preferred embodiment, the at least one cutting edge is formed by a web on the tool toothing as in a scraping wheel. That is, the web is formed by a recess in the tooth head area transverse to the tooth tip edge, which may be provided in the form of a groove as a Schabrad. In this context, it is also provided that the web is formed by providing a Spiralnutung on the tool. This allows a uniform removal without axial relative movement between the tool and toothing.

In a further preferred embodiment of the method, the ablation of the secondary burr in the direction of the toothing axis takes place from the middle of the toothing to the outside, in particular on both sides. Insofar as simultaneous machining on both sides of the toothing is desired, the cutting direction of the cutting edge on one side may also extend from outside to inside in this connection, the removal of the ridge by a plurality of successive cutting machining operations nevertheless takes place from the inside outwards.

In a particularly preferred embodiment, one / the predetermined tool design has a recess in a central region with respect to the tool axis. This can cause on the one hand that in the central region of the tooth flank no cutting machining takes place, on the other hand it allows in manufacturing technology simple way a separation of the tool in two different area, of which a respective is designed for the Sekundärgratentfernung on each side of the toothing. In this design, it can be provided in a preferred embodiment that a spiral groove of differently directed twist is formed with respect to the tool axis of both edge regions, whereby bilateral ablation from the inside to the outside can be realized without interim change of a direction of rotation on the machine axis. However, the indentation could also result from a hollow hollow in the tooth width direction tool. In a particularly preferred embodiment of the method, the toothing is hardened after the secondary deburring and subjected to a fine machining, in particular a honing process. In this way, a high final accuracy of the finished workpiece is ensured.

In terms of device technology, the invention provides an arrangement for machining a toothing with a method according to one of the preceding method aspects, with a particular rotationally driven workpiece spindle for receiving the teeth and a particular rotationally non-rotatable mounting for the machining tool, a non-zero axis cross angle between the workpiece spindle axis and the axis of rotation of the tool storage and a linear positioning axis, via which the center distance of the two axes of rotation is adjustable.

The advantages of the arrangement according to the invention will become apparent from the above-mentioned advantages of the method according to the invention. In the preferred variant of the non-rotatable rotatable support for the machining tool, the machining tool and its bearing form less an independent machine than an additional machining unit. To further simplify the unit, it can be provided that, apart from the linear positioning axis provided on the machining tool side, the machining tool has no further linear machine axes for tool positioning. With regard to rotary positioning axes, it can be provided that the value of the non-zero axis crossing angle can be set via a machine axis. This could be an NC machine axis. In simpler designs, however, it may also be provided that the axis cross angle is indeed adjustable, but not via an NC machine axis, but by hand, steplessly or with a number of spaced setting values for the axis cross angle. In terms of design, a likewise preferred variant is particularly simple, in which the tool rotation axis is fixed in space and in particular the axis of the axle is fixed.

The Achskreuzwinkel is preferably greater than 3 °, more preferably greater than 4 °, in particular greater than 5 ° and preferably less than 35 °, more preferably less than 25 °, in particular less than 15 °.

In a particularly preferred embodiment, the arrangement is integrated in a gear cutting machine designed for producing toothings from blanks. grates, in particular as a particular also a Anfaseinrichtung having separate processing station such that the workpiece spindle is not the Hauptwerkstückspindel on which the blank is clamped for generating teeth. In this way, during the chamfering / deburring on the main workpiece spindle, a subsequent blank for gear generation can already be set up and the main times are reduced. But other uses of the arrangement with single-spindle or multi-spindle machines are also conceivable.

Furthermore, provided by the invention under protection a machine tool, in particular Wälzfräsmaschine with an arrangement according to one of the above-mentioned aspects. This machine tool preferably has a tooth changer from a / of the main workpiece spindle on the workpiece spindle (the complementary tooth formation) spanning workpiece changer. However, the arrangement is also suitable for other machines such as Wälzstoß- or -Schälmaschinen.

In addition, the machine tool has a controller which controls the machine axes of the machine tool for carrying out a method according to one of the method aspects explained above.

Furthermore, the invention provides a suitable for carrying out a method according to one of the above method aspects processing tool under protection, with respect to the tool axis first edge region in the form of a predetermined Schabradgeometrie, a central region deviating from this Schabradgeometrie to avoid a cutting machining engagement shape and the first edge region opposite second edge region, the teeth of which allows the same rolling engagement in the toothing as the predetermined Schabradgeometrie.

Such a tool is relatively easy to produce and has webs in the head region of the toothing of the edge regions of the tool, which extend transversely to the tooth tip edge of the machining tool.

Further features, details and advantages of the invention will become apparent from the following description with reference to the accompanying figures, of which

1 shows a side view of functional areas of a chamfering and deburring device, FIG. 2 shows the positioning of workpiece and machining tool for secondary deburring at an axis cross angle, FIG.

Fig. 3 shows an illustration of the machining tool for secondary deburring, and

4 shows a schematic representation of a hobbing machine with chamfering and deburring station.

Centered in Fig. 1, a gear 2 (schematically without teeth) is shown, which was generated for example by hobbing, at the tooth front edges still has (primary) burrs and is rotationally driven clamped on a spindle, not shown spindle with workpiece spindle axis C4. For the left in Fig. 1 side a known from the prior art Wälzentgrateinheit is arranged, which has two axially spaced Wälzentgraträder W1, W2, the applied under a radial positioning axis X1 contact pressure, the toothed edges of the gear 2 on the upper and lower side plastically transform into a chamfer. The Anfaseinheit 5 also has a machine axis Z1 for axial positioning. The rotation axis C1 of the chamfering device 5 is not driven, the Wälzentgraträder W1 and W2 are driven by the driven by the workpiece spindle drive with spindle axis C4 gear 2. Likewise, however, the rotation axis C1 could also be driven.

However, no gear-shaped smoothing tool is provided between the Wälzentgraträdern W1 and W2, which could smoothly roll the secondary burrs raised on the tooth flanks during chamfering. Rather, on the opposite side (on the right in FIG. 1), a device 6 for secondary burr removal is provided which has a toothed machining tool 7 rotatable about an axis C3. As can be seen better from Fig. 2, in which the gear 2 and the tool 7 is shown in the direction of the Achsabstandsachse to the axes of rotation C4 and C3, the axis of rotation C3 of the machining tool 7 and a Achskreuzwinkel Σ, which runs to Verkanschaulichkeits purposes with approx. 25 ° is drawn, but is usually set for processing to lower values, preferably between 5 and 15 °. The setting of the axis cross angle Σ could be carried out via the axis of rotation A3 (FIG. 1), but it is also possible to provide a rotational axis C3 which is fixed in space with respect to its orientation. About the parallel to the Achsabstandsächse provided linear positioning axis X3 For example, the machining tool 7 can be brought into and out of machining engagement with the gear 2.

As can be seen in Fig. 3, the tool 7 has a in Fig. 3 only indicated teeth 17, on the tooth heads webs 18 are formed similar to a scraper wheel transversely to the tooth tip edge. These webs 18 form cutting edges which, due to the axis cross angle Σ between the spindle axis C4 and the rotation axis C3, abradingly remove the secondary burrs on the tooth flanks near the toothed end edges of the toothed wheel 2 when the machining tool 7 is in rolling machining engagement with the gear wheel 2.

As can be further seen from FIG. 3, the toothing 17 does not extend over the full width of the tool 7. Rather, a recess is provided in an axially central region M, so that the machining tool 7, although integrally formed in this embodiment, the shape two spaced apart by a spacer gears 7L and 7R assumes. Due to the one-piece production, however, it is easier to ensure in the production of the toothing 17 on the tool 7 that the toothings 17 in the regions 7L and 7R are parts of the same, only interrupted toothing, with which the same rolling engagement is possible. The recess in the central region M ensures that no cutting machining of the tooth flanks of the toothed wheel 2 takes place in the region centered with respect to the width direction of the toothed wheel 2. This allows feed marks from milling to be retained.

This non-machining in the center of the gear 2 could also be achieved by the tool 7 being hollow in the tooth width direction (negative crowning), that is to say having a rolling element which is concave in axial section.

As can be further seen from FIG. 3, the webs 18 are of a spiral path 19 offset successively by a number of workpiece teeth. The settings of the directions of twist preferably take place such that the region 7L of the tool 7 causes the secondary burrs from the inside to the outside As a result, the machining contact of a web 18 of a subsequent engaged tooth of the toothing 17 is located axially further outward on the toothed wheel 2. Since the swirl of the spiral 19 in the other region 7R of the tool 7 corresponds to the swirl of the spiral 19 in the region 7L is opposite, also takes place on the other side of the gear 2 a Sekundärgratabtrag from the inside out. In Fig. 4 is sketched yet the structure of a hobbing machine, in which the Anfasstation 5 and Sekundärgratentfernung 6 are integrated. Of the latter, only the axes of rotation C1, C3 and C4 are drawn for reasons of simplified illustration. Also, the Wälzfräs tool page is only schematically referred to WF, which has a milling head with a hob in the usual way. The latter is provided for example in the usual manner with three linear positioning axes (radially X, axially Z parallel to the workpiece axis C2 and tangential Y), wherein the orientation of the shift axis Y along the Wälzfräsdrehachse is provided, and via a rotary machine axis (A) is adjustable (Rotation of the milling head about radial axis X). The shift axis Y could also be a (cross) slide axis.

As can be seen from Fig. 4, the chamfering tool (station 5) and the secondary deburring work 6 do not work on the machining center of the hob, namely on the workpiece spindle C2 (main workpiece spindle), but on the slave workpiece spindle C4. A workpiece changer WW shown only schematically in FIG. 4 spends blanks on the workpiece spindle C2, workpieces milled from the workpiece spindle C2 onto the sub spindle C4, and chamfered workpieces with eliminated secondary ridge away from the workpiece spindle C4 for removal. For example, the workpiece changer is a three-arm rotary changer as indicated in Fig. 4.

A secondary burr raised on the end face of the gear wheel 2 during chamfering, although not shown in the figures, can also be eliminated, for example by filing or twisting off.

The invention is not limited to the embodiment shown in the embodiment. Rather, the features of the above description and the appended claims, alone and in combination, may be essential to the practice of the invention in its various embodiments.

Claims

1 . Method for machining a toothing (2) rotating about its toothing axis, in which a secondary tooth formed during a chamfering of a toothed edge of the toothing on a tooth flank of the toothing in a region near the tooth face is produced by a rolling machining engagement with a machining tool (7) rotating about a tool axis ) at least for the most part, characterized in that the machining tool (7) has at least one cutting edge which is provided by providing a non-zero Achskreuzwinkels (Σ) between the toothing axis (C4) and the tool axis (C3) in the machining engagement a secondary ridge cutting away erosive movement.

2. The method of claim 1, wherein the Sekundärgrat on the other tooth flank side is at least for the most part eliminated, in particular in the same machining engagement and / or in particular the same machining tool (7).

3. The method of claim 1 or 2, wherein in the machining engagement no cutting machining in the center of the tooth axis with respect to the tooth surface of the toothing (2), in particular due to a predetermined tool design.

4. The method according to any one of the preceding claims, wherein the at least one cutting edge is formed by a web (18) on the tool toothing (17) as in a Schabrad.

5. The method of claim 4, wherein the web is formed by providing a Spiralnutung (19) on the tool (17).

6. The method according to any one of the preceding claims, wherein the removal of the secondary burr takes place in the direction of the toothing axis seen from the tooth center to the outside, in particular in each case on both sides.

7. The method according to any one of the preceding claims, in which one / the predetermined tool design in a central region with respect to the tool axis (M) has a recess.

8. The method according to any one of the preceding claims, in which one / the predetermined tool design with respect to the tool axis both edge regions a Spiralnutung differently directed swirl (19L, 19R).

9. The method according to any one of the preceding claims, wherein the toothing after the secondary deburring hardened and subjected to a fine machining, in particular a honing process.

10. Arrangement (6) for machining a toothing (2) with a method according to one of the preceding claims, with a particular rotationally driven workpiece spindle for receiving the toothing and a particular rotationally non-rotatable mounting for the machining tool (7), a non-zero axis cross angle (Σ) between the workpiece spindle axis (C4) and the axis of rotation (C3) of the tool storage and a linear positioning axis (X3), via which the center distance of the two axes of rotation is adjustable.

1 1. Arrangement according to claim 10, integrated in a designed to produce gears from blanks gear cutting machine (10), in particular as a particular chamfering device (5) having separate processing station such that the workpiece spindle (C4) not the Hauptwerkstückspindel (C2) is on which the blank is set up for gear production.

12. Machine tool (10), in particular hobbing machine with an arrangement according to one of claims 10 or 11.

13. Machine tool according to claim 12, with a toothing of one / the Hauptwerkstückspindel (C2) on the workpiece spindle (C4) spreader workpiece changer (WW).

14. Machine tool according to claim 12 or 13, with a controller (99) which controls the machine axes of the machine tool for performing a method according to any one of claims 1 to 9.

15. machining tool (7) for performing a method according to one of claims 1 to 9, with respect to the tool axis (C3) first edge region (7L) in the form of a predetermined Schabradgeometrie, a central region (M) with this Schabradgeometrie to avoid a and a second edge region (7R) opposite the first edge region, the teeth of which permit the same rolling engagement with the toothing as with the predetermined bevel wheel geometry.