Gear Cutting Tools

Rotor hobs, for roughing
for screw compressors
for male and female rotors
as heavy-duty roughing hobs
with 16 flutes
axially parallel gashes
single start
with keyway
l 1
l 3
for male rotors
d 1 d 2
KHSS-E EMo5Co5
Cat.-No.
2091 relief turned
for female rotors
Dimensions in mm
Cutter dimensions
Rotor dia. m Profile height d 1 I 3 I 1 d 2
47/44,5 ≈ 5,2 ≈ 10,2 112 90 106 40
81,6 ≈ 9,1 ≈ 17,5 140 154 170 50
102 ≈ 11,4 ≈ 22 170 184 200 60
127,5 ≈ 14,2 ≈ 27,5 212 234 250
163,2 ≈ 18,2 ≈ 35,5 265 299 315 80
204 ≈ 22,7 ≈ 44 305 319 335 100
204 ≈ 22,7 ≈ 44 335
The structural dimensions are approximate values for rotor measurements L/D = 1.65.
When ordering, workpiece drawings of the rotors and data abaut the profile
at the face plane (list of coordinates) must be made available.
Owing to their size, not all rotors
can be generated by hobbing. Furthermore,
the choice of tools is also
influenced by the process already
in place and the machines
which are available.
FETTE played a leading part in the
introduction of the hobbing process
for the manufacture of rotors.
FETTE can therefore call upon
considerable experience in advising
its customers.
The advantages of the hobbing method are undisputed and can be summarized
as follows:
■ Quick and trouble-free production of rotors with good surfaces and accurate
profiles and pitch.
■ The sealing strips on the tooth tip and the sealing grooves in the tooth root
of the rotors can be generated in one operation with the flanks.
■ Hobbed rotors can be exchanged at any time, thanks to their uniform accuracy.
■ Simple and economical maintenance of the tools, since the hobs are only
reground on the cutting face.
55