The Gear Hobbing Process

The Gear Hobbing Process Dennis ,Gimpert K'oepfer America Limited Partnership" South Elgin.IL ear hobbing . cessive cuts on the workpiece, with the...
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The Gear Hobbing Process Dennis ,Gimpert K'oepfer America Limited Partnership" South Elgin.IL

ear hobbing

.

cessive cuts on the workpiece, with the work-

refers to the fact

piece ,in a slightly different po ition for each

is a generating

The term generating

proces

that the gear tooth form cut is lIotlllc

cut (see Fig. Ib). Several cutting edge

conjugate form of the cutting tool,lhe

tool will be cutting at the arne time.

hob. During workpiece relationship. typically

hobbing

rotational.

[)uring this rotation, the hob i

fed axiaUy withall the teeth being

edges.

Each cutting

tooth is also relieved

radially to provide chip clearance behind the cutting edge. This also allowsthe be sharpened

hob face to

and still maintain the original

tooth shape. The final profile of the tooth

j

hob, the workpiece will advance one tooth for

created by a number of flats blending togeth-

each revolution of the cutter. Wilen bobbing a

er. The number of flats corresponds

twenty-tooth

number

gear" the hob will rotate twenty will rotate once.

of cutting

workpiece

gashes

tooth during

which a single

to the pass the

rotation.

The profile is formed by the equally spaced

Thus, the greater the number of gashes in the

cutting edgesaroundthe

hob, thegreater

hob, each taking sue-

18 fig.l a & b TECHNO~OGY

a wonn with gashes.

axially across it to produce these cutting

gradually formed as the tool traverses the work

times, while the workpiece

GEAR

CUi

face (see Fig. Ia). FOIl" a spur gear being cut with a single start

:38

The hob is basically

both the hob and the

rotate ill a continuous

of the

the number of flats along the

1b:

Length Active Length

~.15J"

DP "Fine Pitch is

-

---

Filg. 2 profile which improves

the "smoothness"

of

the tooth profile.

The Cutter Bobbing

is a generating

process,

and the

hob win not cut the same shape as the cutting tool form, An unmodified is produced by

.