HOBBING MACHINE, COMPRISING A HOBBING SLIDE AND A CHAMFERING SLIDE ON A COMMON RAIL SYSTEM

Abstract

A hobbing machine is disclosed having a workpiece spindle, by means of which a workpiece can be rotated about a workpiece axis, a hobbing head, at least one chamfering device, a first slide with a first slide guide system, wherein the hobbing head is arranged on the first slide, and a rail system. The first slide, by means of its first slide guide system, is arranged in a displaceable manner on the rail system. The hobbing machine also has a second slide with a second slide guide system. The at least one chamfering device is arranged on the second slide. Also, the second slide, by means of its second slide guide system, is arranged in a displaceable manner on the rail system, such that the first slide and the second slide can be displaced on an identical portion of the rail system. Presented is a structurally simple hobbing machine by means of which a workpiece can be hobbed and chamfered in a short period of time.

Claims

1. A hobbing machine, comprising: a workpiece spindle, by means of which a workpiece can be rotated about a workpiece axis; a hobbing head; at least one chamfering device; a first slide with a first slide guide system, wherein the hobbing head is arranged on the first slide; a rail system, wherein the first slide, by means of its first slide guide system, is arranged in a displaceable manner on the rail system; and a second slide with a second slide guide system, wherein the at least one chamfering device is arranged on the second slide; and wherein the second slide, by means of its second slide guide system, is arranged in a displaceable manner on the rail system, such that the first slide and the second slide can be displaced on an identical portion of the rail system.

2. The hobbing machine as claimed in claim 1, wherein both the first slide and the second slide are designed in the form of driven slides.

3. The hobbing machine as claimed in claim 2, wherein each driven slide comprises a dedicated motor drive, by means of which the driven slide can be displaced on the rail system.

4. The hobbing machine as claimed in claim 2, wherein a common motor drive is provided for the two driven slides.

5. The hobbing machine as claimed in claim 4, wherein the common motor drive comprises a drive motor, which is arranged on a machine bed and drives an externally threaded drive spindle, wherein the first slide has a first internally threaded force-transmission element, and the second slide has a second internally threaded force-transmission element, and wherein the first force-transmission element and the second force-transmission element are both seated on the drive spindle.

6. The hobbing machine as claimed in claim 5, wherein the externally threaded drive spindle is a ball screw, wherein the first internally threaded force-transmission element is a nut fastened on the first slide, and wherein the second internally threaded force-transmission element is a nut fastened on the second slide.

7. The hobbing machine as claimed in claim 1, wherein one of the slides is designed in the form of a driven slide, wherein a motor drive is provided for the driven slide and can displace the driven slide on the rail system, wherein the other slide is designed in the form of a non-driven slide, and wherein a coupling device is provided, by means of which the driven slide and the non-driven slide can be coupled to one another mechanically and are coupled to one another mechanically.

8. The hobbing machine as claimed in claim 7, wherein the non-driven slide has a dedicated position sensor which can determine a displacement position of the non-driven slide on the rail system.

9. The hobbing machine as claimed in claim 7, wherein the driven slide is the first slide and the non-driven slide is the second slide.

10. The hobbing machine as claimed in claim 7, wherein the coupling device is designed to connect the two slides to one another rigidly along a displacement axis on the rail system.

11. The hobbing machine as claimed in claim 10, wherein the slides form mutual abutment surfaces which face one another, as seen in relation to the displacement axis, and wherein the coupling device comprises a tensioning device, which engages around at least parts of the two slides and braces the slides, with abutting abutment surfaces, against one another.

12. The hobbing machine as claimed in claim 1, wherein the workpiece axis of the workpiece spindle and a displacement axis of the rail system run parallel to one another.

13. The hobbing machine as claimed in claim 12, wherein the workpiece axis and the displacement axis run horizontally.

14. The hobbing machine as claimed in claim 1, wherein the first slide guide system and the second slide guide system are formed with rolling bearings.

15. The hobbing machine as claimed in claim 1, wherein two chamfering devices are arranged on the second slide.

16. The hobbing machine as claimed in claim 1, wherein the at least one chamfering device is designed for chamfering by skiving.

17. The hobbing machine as claimed in claim 16, wherein the at least one chamfering device is designed for chamfering by skiving at an azimuthal angle >0 and a polar angle <90.

18. The hobbing machine as claimed in claim 17, wherein the workpiece axis runs along an x direction, wherein a toolholder can be displaced on the second slide in each case linearly in a y direction and a z direction, wherein the x, y and z directions form a right-angled coordinate system, wherein a tool spindle for a toothed tool is arranged on the toolholder, and wherein a tool axis, about which the tool spindle can be rotated, is pivoted by the azimuthal angle >0 in an xy plane in relation to the x direction and by the polar angle <90 in relation to the z direction.

19. The hobbing machine as claimed in claim 18, wherein the x direction and the z direction run horizontally.

20. The hobbing machine as claimed in claim 18, wherein a rotary mount is arranged on the toolholder and can be rotated by a motor about an axis of rotation, wherein the axis of rotation runs parallel to the z direction, and wherein the tool spindle is arranged on the rotary mount.

21. The hobbing machine as claimed in claim 20, wherein two chamfering devices for chamfering by skiving are arranged on the second slide, wherein also a further tool spindle for a further toothed tool is arranged on the rotary mount, and wherein a further tool axis, about which the further tool spindle can be rotated, is pivoted by a further azimuthal angle w in the xy plane in relation to the x axis and by a further polar angle w in relation to the z axis, where w= and w=.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The invention will be explained in more detail with reference to exemplary embodiments and is illustrated in the drawing, in which:

[0038] FIG. 1 shows a schematic perspective view, as seen obliquely from the front, of a first embodiment of a hobbing machine according to the invention, without a counter bearing;

[0039] FIG. 2 shows a schematic perspective view, as seen obliquely from the rear, of the hobbing machine from FIG. 1, with a counter bearing;

[0040] FIG. 3 shows a schematic plan view of the hobbing machine from FIG. 2;

[0041] FIG. 4 shows a schematic perspective view, as seen obliquely from the rear, of the second slide of the hobbing machine from FIG. 1;

[0042] FIG. 5a shows a schematic perspective view, as seen obliquely from the front, of the second slide of the hobbing machine from FIG. 1, including an illustration of the orientation of a lower chamfering tool;

[0043] FIG. 5b shows a schematic perspective view, as seen obliquely from the front, of the second slide of the hobbing machine from FIG. 1, including an illustration of the orientation of an upper, further chamfering tool;

[0044] FIG. 6 shows a schematic plan view of a second embodiment of a hobbing machine according to the invention;

[0045] FIG. 7 shows a schematic plan view of a third embodiment of a hobbing machine according to the invention; and

[0046] FIG. 8 shows a schematic side view of a fourth embodiment of a hobbing machine according to the invention, comprising a coupling device with a tensioning device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] FIG. 1 illustrates a schematic perspective view, as seen obliquely from the front, and FIG. 2 illustrates a schematic perspective view, as seen obliquely from the rear, of a first embodiment of a hobbing machine 1 according to the invention.

[0048] A machine bed 2 has arranged on it a fixed-location workpiece spindle 3, which can be rotated about a horizontal workpiece axis WSA, cf. also machine axis C1. The workpiece axis WSA here defines an x direction, which together with the vertical y direction and the likewise horizontal z direction forms a right-angled coordinate system. A workpiece 21 clamped in the workpiece spindle 3 can be supported on a counter bearing 4 (not illustrated in FIG. 1, but cf. FIG. 2), which can be displaced in the x direction.

[0049] Also arranged on the machine bed 2 is a rail system 5, that in this case comprises two rails 5a, 5b. The rails 5a, 5b run in the horizontal direction parallel to the workpiece axis WSA. Both a first slide 11 and a second slide 12 are mounted in a displaceable manner on the rail system 5 (common rail system), here on both rails 5a, 5b in each case. Accordingly, the two slides 11, 12 can travel, at least in a central region, on an identical portion 36 of the rail system 5. For this purpose, the first slide 11 has a first slide guide system 13, comprising a plurality of (in this case four) rolling bearings (rolling-bearing elements) 13a, and the second slide 12 has a second slide guide system 14, likewise comprising a plurality of (in this case four) rolling bearings (rolling-bearing elements) 14a. The rolling bearings 13a, 14a comprise rollers or balls (not illustrated specifically), which roll on the rails 5a, 5b.

[0050] In the embodiment shown, the first slide 11 is designed in the form of a driven slide and can be displaced on the rail system 5, cf. machine axis X, by means of a motor drive 15, which comprises a drive motor 35. In the embodiment shown, the second slide 12 is designed in the form of a non-driven slide and is coupled mechanically to the first slide 11. As a result of being pushed and pulled by the first slide 11, it is also possible for the second slide 12 to be displaced on the rail system 5 (more on this in conjunction with FIG. 3 hereinbelow).

[0051] A hobbing head 16 is arranged on the first slide 11 and can be displaced along the machine axes Y1 and Z1, in particular can be positioned against a workpiece 21. The second slide 12 has arranged on it in this case two chamfering devices 17, 18, which are designed for chamfering by skiving with double tilting (more on this in conjunction with FIG. 4, FIG. 5a and FIG. 5b hereinbelow). A toolholder 19 can be displaced on the second slide 12 along the machine axes Y2, Z2, in particular in order for the chamfering devices 17, 18 to be positioned against a workpiece 21. The toolholder 19, in turn, bears a rotary mount 20, which can be rotated about an axis of rotation DA, which runs parallel to the z direction. Two tool spindles of the chamfering devices 17, 18 are arranged on the rotary mount 20.

[0052] The positioning systems on the two slides 11, 12 are formed independently of one another. As a result of the hobbing and chamfering operations (including the associated positioning systems) being distributed between the two slides 11, 12, each individual slide 11, 12 is comparatively small and lightweight.

[0053] FIG. 3 shows the hobbing machine 1 from FIG. 1 and FIG. 2 in a plan view, which will be used to explain the coupling and the driving of the slides 11, 12 of this embodiment.

[0054] The motor drive 15 has the drive motor 35, which is arranged on the machine bed 2; the drive motor 35 drives an externally threaded drive spindle 22, in this case a ball screw. The drive spindle 22 extends parallel to the x direction, that is to say parallel to the displacement axis VA of the rail system 5. The drive spindle 22 here runs along beneath the two slides 11, 12. An internally threaded force-transmission element 23, in this case a nut 24, is positioned on (screwed onto) the drive spindle 22. The force-transmission element 23 is fixed, for example screwed, to the first slide 11 in a manner which is not illustrated specifically. Rotation of the drive spindle 22 then causes the force-transmission element 23, which is retained in a rotationally fixed manner by the slide 11 fixed to it, to push ahead (with screwing action) along the displacement direction VA of the common rail system 5; the first slide 11 is carried along in the process. The first slide 11 is thus a driven slide.

[0055] The second slide 12 is connected to the first slide 11 by a coupling device 25, which is designed in the form of a coupling bar (see, in this respect, FIG. 4). When the first slide 11 moves along the displacement axis VA, the second slide 12 is pushed or pressed by the first slide 11, such that the second slide 12 is also displaced on the common rail system 5.

[0056] It should be noted that the force-transmission element 23 is arranged here in the vicinity of the coupling device 25, as a result of which the positioning accuracy of the second slide 12 is improved.

[0057] The second slide 12 preferably has a dedicated position sensor (measuring head) 26, which in this case interacts with a positioning system integrated in the front rail 5a. This makes it possible for positioning errors of the second slide 12, for example caused by mechanical hystereses in the coupling device 25, to be detected and corrected (by appropriate displacement of the second slide 12, the motor drive 15 being used indirectly). The position sensor 26 is preferably integrated in a rolling bearing (a rolling-action bearing shoe).

[0058] FIG. 4 will be used to explain the second slide 12 and the coupling device 25 in more detail.

[0059] The coupling device 25 here is designed in the form of a coupling bar with two holes, wherein a respective screw (not illustrated specifically) is guided through one of the holes 27a, 27b and screwed into a threaded bore (not illustrated specifically) of the respective slide. Although the coupling bar is rotatable on the screws, no obvious rotation of the coupling bar takes place during operation, since the slides 11, 12 are secured laterally (in the z direction) by the rail system 5. The coupling device 25 therefore acts rigidly in the direction of the displacement axis (corresponding to the x direction).

[0060] Also shown is the toolholder 19, which can be displaced both in the y direction (cf. machine axis Y2) and in the z direction (cf. machine axis Z2) via a cross-slide system. The cross-slide system here comprises an intermediate support 28. In addition, the toolholder 19, along with the entire second slide 12, can be displaced in the x direction (by coupling to the first slide 11, which can be displaced along the machine axis X).

[0061] The rotary mount 20 is arranged on the toolholder 19 and can be rotated by a motor about the axis of rotation DA, cf. machine axis A2. The tool spindle 29 of the (lower) chamfering device 17 and the tool spindle 30 of the (upper) further chamfering device 18 are arranged on the rotary mount 20. The tool axis WZA of the tool spindle 29 is tilted, in this case in a fixed manner, in relation to the further tool axis wWZA of the tool spindle 30. The tool spindle 29 and the further tool spindle 30 can be rotated by a motor, cf. machine axes C6, C5, in order each to drive a retained (clamped-in) toothed tool 31, 32.

[0062] FIG. 5a will be used to explain the orientation of the tool axis WZA of the tool spindle 29 of the lower chamfering device 17. It should be noted here that the axis of a workpiece which is to be machined (not depicted) runs along the x direction. An auxiliary coordinate system x/y/z, which has been shifted in a parallel state in relation to the actual xyz coordinate system, is depicted on the tool 31 so that the angular relationships can be seen to better effect.

[0063] The tool axis WZA is pivoted by a polar angle in relation to the z direction. The difference between the polar angle and 90 (that is to say the angle between the tool axis WZA and the xy plane) is referred to as the latitude angle . Furthermore, a projection 33 of the tool axis WZA onto the xy plane has an azimuthal angle (also referred to as the axis-crossing angle) in relation to the x direction.

[0064] Accordingly, the tool axis WZA is double-tilted in relation to the tool axis (which runs parallel to the x direction). This allows chamfering by skiving on the workpiece with double tilting of the tool axis WZA in relation to the workpiece axis, as described in DE 10 2014 218 082 A1, of which the content is included by way of reference in this description.

[0065] FIG. 5b shows the orientation of the further tool axis wWZA of the further tool spindle 30 of the upper chamfering device 18. An auxiliary coordinate system x/y/z, which has been displaced in a parallel state in relation to the actual xyz coordinate system, is depicted on the further tool 32 so that the angular relationships can be seen to better effect.

[0066] The further tool axis wWZA is pivoted by a further polar angle w in relation to the z direction. The difference between the further polar angle w and 90 (that is to say the angle between the further tool axis wWZA and the xy plane) is referred to as the further latitude angle w. Furthermore, a projection 34 of the further tool axis wWZA onto the xy plane has a further azimuthal angle w in relation to the x direction.

[0067] The rotary position of the rotary mount 20 (with the chamfering devices 17, 18 directly one above the other in the y direction and y direction) and the fixed tilting of the tool axis WZA and of the further tool axis wWZA in relation to one another here means that

w= and

w=.

[0068] The two chamfering devices 17, 18 can chamfer left-hand and right-hand tooth flanks on one side of a workpiece. Rotation of the rotary mount 20 by 180 about its axis of rotation DA can achieve conditions appropriate for chamfering a side of the workpiece which is located opposite (as seen in the x direction).

[0069] It should be noted that a tool 31, 32 is typically positioned against the workpiece in each case such that the perpendicular of a zone of contact between the tool 31, 32 and workpiece onto the workpiece axis defines the z direction.

[0070] FIG. 6 will be used to explain a second embodiment of a hobbing machine 1 according to the invention, this embodiment corresponding largely to the embodiment from FIG. 1 and FIG. 2, and therefore it is only the significant differences which will be explained here.

[0071] This embodiment provides a common motor drive 60 for the first slide 11 and the second slide 12. A drive motor 66 of the common motor drive 60 drives an externally threaded drive spindle 65, in this case a ball screw, which runs beneath the first and second slides 11, 12. A first internally threaded force-transmission element 61 in the form of a nut 63 and a second internally threaded force-transmission element 62 in the form of a nut 64 are seated on the drive spindle 65. The first force-transmission element 61 is fixed, for example screwed, to the first slide 11 in a manner which is not illustrated any more specifically, and the second force-transmission element 62 is fixed, for example screwed, to the second slide 12 in a manner which is not illustrated any more specifically.

[0072] Rotation of the drive spindle 65 by the drive motor 66 of the common motor drive 60 causes the nuts 63, 64, which are retained in a rotationally fixed manner on their respective slide 11, 12, to move (with screwing action) along the displacement axis of the common rail system 5. The nuts 63, 64 carry along their respective slides 11, 12 in the process.

[0073] The two slides 11, 12 are therefore driven separately in each case, but move synchronously in relation to one another at a fixed distance apart (with the exception of any error in the pitch of the drive spindle 65), without a mechanical coupling device connecting the two slides 11, 12. Both the first slide 11 and the second slide 12 here are driven slides.

[0074] FIG. 7 will be used to explain a third embodiment of a hobbing machine 1 according to the invention, this embodiment corresponding largely to the embodiment from FIG. 1 and FIG. 2, and therefore it is only the significant differences which will be explained here.

[0075] In the case of this embodiment, the first slide 11 has a dedicated motor drive 71 and the second slide 12 has a dedicated motor drive 70.

[0076] A drive motor 78 of the motor drive 71 drives an externally threaded drive spindle 73, in this case a ball screw, on which an internally threaded force-transmission element 74, in this case a nut 76, has been positioned (screwed). The nut 76 is fastened, for example screwed, on the first slide 11 in a manner which is not illustrated any more specifically. A drive motor 79 of the motor drive 70 drives an externally threaded drive spindle 72, in this case a ball screw, on which an internally threaded force-transmission element 75, in this case a nut 77, has been positioned (screwed). The nut 77 is fastened, for example screwed, on the second slide 12 in a manner which is not illustrated any more specifically. The drive spindles 72, 73 run parallel to one another beneath the two slides 11, 12.

[0077] Rotation of the drive spindle 73 by the drive motor 78 of the motor drive 71 causes the nut 76, which is retained in a rotationally fixed manner on the first slide 11, to move (with screwing action) along the displacement axis of the common rail system 5. Rotation of the drive spindle 72 by the drive motor 79 of the motor drive 70 causes the nut 77, which is retained in a rotationally fixed manner on the second slide 12, to move (with screwing action) along the displacement axis VA of the common rail system 5. The nuts 76, 77 carry along their respective slides 11, 12 in the process.

[0078] The two slides 11, 12 here are driven not just separately, but also independently of one another. In particular it is possible for one of the slides 11, 12 to be moved along the displacement axis VA while the other slide 11, 12 is at rest. Both the first slide 11 and the second slide 12 here are driven slides.

[0079] FIG. 8 will be used to illustrate a coupling device as can be used within the context of the invention, for example for a hobbing machine similar to that in FIGS. 1, 2 and 3. It is only the significant differences which will be explained. For this purpose, FIG. 8 shows a schematic side view of the hobbing machine 1.

[0080] The first slide 11 is a driven slide, which in this case is driven by the motor drive 15, having a drive motor 35, via the drive spindle 22 and the force-transmission element 23. The second slide 12 is a non-driven slide. The slides 11, 12 are coupled to one another mechanically by a coupling device 25, and therefore they can be displaced jointly on the common rail system 5, by way of their respective slide guide systems 13, 14, on rolling bearings 13a, 14a.

[0081] In the embodiment shown, the slides 11, 12 have mutual abutment surfaces 80, 81, by way of which they are arranged in the state in which they have been moved against one another (as seen in relation to the displacement axis VA), that is to say they butt against one another. The mutual abutment surfaces 80, 81 here run perpendicularly to the displacement axis VA. The coupling device 25 here comprises a tensioning device 82. An externally threaded bolt 87 projects through two hole-containing lugs 83, 84 on the first slide 11 and on the second slide 12. Appropriately internally threaded tensioning nuts 85, 86 are fitted on the outside of the threaded bolt 87, on the far side of the lugs 83, 84 in each case, and said tensioning nuts engage around the lugs 83, 84 and subject the threaded bolt 87 to elastic tensile stressing. Accordingly, the threaded bolt 87 pulls the slides 11, 12 toward one another. The tensioning position of the tensioning nuts 85, 86 is secured here by lock nuts 88, 89. The coupling device 25 here ensures fully rigid coupling of the slides 11, 12, in particular in the x direction and z direction.

LIST OF REFERENCE SIGNS

[0082] 1 Hobbing machine [0083] 2 Machine bed [0084] 3 Workpiece spindle [0085] 4 Counter bearing [0086] 5 (Common) rail system [0087] 5a, 5b Rails [0088] 11 First slide [0089] 12 Second slide [0090] 13 First slide guide system [0091] 13a Rolling bearing (rolling-bearing element, rolling-action bearing shoe) on the first slide [0092] 14 Second slide guide system [0093] 14a Rolling bearing (rolling-bearing element, rolling-action bearing shoe) on the second slide [0094] 15 Motor drive (for a driven slide) [0095] 16 Hobbing head [0096] 17 (Lower) chamfering device [0097] 18 Further (upper) chamfering device [0098] 19 Toolholder [0099] 20 Rotary mount [0100] 21 Workpiece [0101] 22 Drive spindle (for a driven slide) [0102] 23 Force-transmission element [0103] 24 Nut [0104] 25 Coupling device [0105] 26 Position sensor [0106] 27a, 27b Holes [0107] 28 Intermediate support [0108] 29 Tool spindle [0109] 30 Further tool spindle [0110] 31 Toothed tool [0111] 32 Further toothed tool [0112] 33 Projection of tool axis onto xy plane [0113] 34 Projection of further tool axis onto xy plane [0114] 35 Drive motor [0115] 36 Identical portion of the rail system [0116] 60 Common motor drive [0117] 61 First force-transmission element [0118] 62 Second force-transmission element [0119] 63 Nut (first slide) [0120] 64 Nut (second slide) [0121] 65 Drive spindle [0122] 66 Drive motor (common motor drive) [0123] 70 Motor drive (for second slide, in the case of two slides being driven independently of one another) [0124] 71 Motor drive (for first slide, in the case of two slides being driven independently of one another) [0125] 72 Drive shaft [0126] 73 Drive shaft [0127] 74 Force-transmission element (first slide) [0128] 75 Force-transmission element (second slide) [0129] 76 Nut (first slide) [0130] 77 Nut (second slide) [0131] 78 Drive motor (first slide) [0132] 79 Drive motor (second slide) [0133] 80 Abutment surface (first slide) [0134] 81 Abutment surface (second slide) [0135] 82 Tensioning device [0136] 83 Hole-containing lug (first slide) [0137] 84 Hole-containing lug (second slide) [0138] 85 Tensioning nut (first slide) [0139] 86 Tensioning nut (second slide) [0140] 87 Threaded bolt [0141] 88 Lock nut (first slide) [0142] 89 Lock nut (second slide) [0143] DA Axis of rotation [0144] VA Displacement axis [0145] WSA Workpiece axis [0146] WZA Tool axis [0147] wWZA Further tool axis [0148] Latitude angle [0149] w Further latitude angle [0150] Azimuthal angle [0151] w Further azimuthal angle [0152] Polar angle [0153] w Further polar angle