Page 187 - Gear Technology Solutions

proportional slot width taper and a proportional tooth thickness taper along the
face width. This rule applies in the standard case where face hobbing cutters with
equally spaced blades are used. Coupling members are in all common cases re-
quired to be mirror images of each other. A proportional slot width taper along the
face width, which is equal to the tooth thickness taper, presents the only geomet-
rical solution for mirror image coupling members in order for the teeth of the one
member to fit exactly into the slots of the other member.

Figure 2: Cutter arrangement of the traditional process

A top view onto the generating gear for a face coupling with only 2 teeth repre-
sented is shown in Figure 2. The rotational position of generating gear is adjusted
such that 50% of the slot space angle is above the center line and 50% is below
the center line. Both cutter parts (for convex and concave flank cutting) have dif-
ferent cutter radii (to realize length crowning) and need to accommodate different
spiral angles (in order to compensate the spiral angle errors caused by the deden-
)
dum angle Dg. Cutting of a face hobbed coupling in a completing process there-
fore requires different basic settings for the cutter part which carries the inside
blades versus the cutter part which carries the outside blades. The direction and
the length of vector RWIB defines the length and direction of the vector EXIB which

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