Page 475 - Gear Technology Solutions

flank form optimizations of straight bevel gears are possible without grinding
wheel design change:

Straight Bevel Gear Flank Form Changes without Grinding Wheel Change:

► Tooth thickness
► Tooth depth
► Spiral angle independent on both flanks
► Pressure angle independent on both flanks
► Length crowning independent on both flanks
► Profile crowning independent on both flanks
► Kinematic tip relief independent on both flanks

In case of face gears, the tool profile has an involute or semi-involute shape.
This shape is basically given by the cylindrical pinion the face gear will be
mated with. Due to the fact that the face gear flank surface geometry is devel-
oped with top-heel UMC-motions, root-toe UMC-motions and twist motions as
well as a virtual tool profile shift, the freedoms of Uniflex optimizations are
much greater than expected for a generating process with a permanently coat-
ed CBN grinding wheel. The explanation is the fact that Uniflex not only per-
forms a generating motion but in addition envelopes the flank surface in face
width and profile direction with its swing motion. In general, it can be stated
that in all cases where the mating pinion of a face gear remains unchanged
(regarding number of teeth, module and profile shift factor), the profile design
parameters shown in Figure 47 remain unchanged. Figure 47 shows that the
active cutting or grinding side of the profile is defined by the edge radius, the
Toprem radius, the (main) radius of curvature, the Flankrem radius and the
shoulder radius. The pressure angle on the face gear flank surfaces is created
in the manufacturing machine by the pressure angle shown in Figure 47 and
the relative inclination between tool and workpiece. A change of the relative
inclination will change the pressure angle of the workpiece without the re-
quirement of a new tool geometry. The following flank form optimizations with-
out grinding wheel design change are possible:

Face Gear Flank Form Changes without Grinding Wheel Change:

► Tooth thickness
► Tooth depth
► Spiral angle independent on both flanks
► Pressure angle independent on both flanks
► Length crowning independent on both flanks
► Surface twist crowning independent on both flanks
► Kinematic top-heel and root-toe modification

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