Method for gear shaping a toothing, control program, and gear shaping machine for carrying out the method
The invention relates to a method for gear shaping a toothing ( 55 ) with a specified normal pitch (m n ), angle of action (α), and optionally a helix angle (β) on a workpiece ( 50 ), wherein a shaper cutter ( 40 ) moving in stroke cycles with a specified stroke length (h) removes material from the workpiece in multiple working strokes in a rolling machining engagement, thereby forming contact tracks, wherein the contact track on the partial circle in the stroke center runs at an angle (γ) to the flank line ( 57 ) at least for a first plurality of strokes, the cotangent of said angle being smaller than or equal to the product of a constant of 40, preferably 33, in particular 25, and a geometry/process factor.
1 . Method for gear shaping a toothing with a specified normal pitch (m n ), angle of action (α), and a helix angle (β) on a workpiece, wherein a shaper cutter moving in stroke cycles with a specified stroke length (h) removes material from the workpiece in multiple working strokes with the shaper cutter in a rolling machining engagement with the workpiece, thereby forming contact tracks,
wherein each of the contact tracks for at least a first plurality of the working strokes has a respective longitudinal direction that runs at an angle γ to a flank line of the toothing, the cotangent of said angle γ being smaller than or equal to the product of constants K 1 and K 2 , wherein K 1 is in the range of 19.4 to 40, and K 2 is a geometry-process factor of K2=K h ·K m ·K α ·K β with K h =h [mm]/20, K m =3/m n [mm], K α =sin 20°/sin α and K β =cos β.
2 . Method according to claim 1 , wherein the shaper cutter is fed via the first plurality of strokes, and wherein a feed parameter in the first plurality of strokes is less than 1.4, which feed parameter is defined by the quotient of an amount of radial feeding per workpiece revolution and a lifting amount of the shaper cutter between a working stroke and a return stroke in the first plurality of strokes.
3 . Method according to claim 2 , wherein the feed parameter is less than 1.3.
4 . The method of claim 2 wherein the shaper cutter is fed via the first plurality of strokes in a constant spiral feed.
5 . Method according to claim 1 wherein the first plurality of strokes takes place over a feed region with a predominant share of the overall feed for completion of the shaped toothing, and the cotangent γ is greater than 40·K 2 over a subsequent further feed region.
6 . Method according to claim 1 wherein during a last feeding of the shaper cutter to a final feed depth for machining of the shaped toothing, which last feeding is subsequent to the first plurality of strokes, the cotangent γ is greater than 80·K 2 .
7 . Method according to claim 1 wherein the toothing is a straight toothing or the helix angle of the toothing is less than 14°.
8 . Method according to claim 1 wherein a width of a tooth of the toothing is at least 60% of a stroke length of each of the working strokes of the first plurality of strokes.
9 . Method according to claim 1 wherein a number of the working strokes per workpiece revolution is not a whole number.
10 . Method according to claim 1 wherein the shaper cutter is moved in the multiple working strokes, and is also moved in corresponding return strokes, wherein a respective double stroke is constituted by a respective one of the working strokes in combination with a corresponding one of the return strokes, and wherein the shaper cutter is moved at a stroke number rate that is at least 30 double strokes/min.
11 . Method according to claim 1 wherein a tooth width of the toothing is greater than 15 mm.
12 . Gear shaping machine comprising a controller, the controller being programmed to cause the gear shaping machine to perform the method set forth in claim 1 . and the gear shaping machine further comprising the shaper cutter.