ISSN 1068-798X, Russian Engineering Research, 2018, Vol. 38, No. 2, pp. 98–104. © Allerton Press, Inc., 2018.
Original Russian Text © Vl.V. Bushuev, V.V. Bushuev, V.A. Novikov, 2017, published in Vestnik Mashinostroeniya, 2017, No. 11, pp. 70–76.
Kinematic Errors in the Generating Train
of New Generation Gear-Hobbing Machine with Direct Drives
Vl. V. Bushuev*, V. V. Bushuev, and V. A . Novikov
Stankin Moscow State Technical University, Moscow, Russia
Abstract—The appearance of high-frequency kinematic errors in the generating train is analyzed for the new
generation of gear-hobbing machines. Methods of diminishing those high-frequency components are pro-
posed. The transfer of cyclic errors in the generating train to the gear being produced is discussed.
Keywords: gear, kinematic errors, cyclic errors, direct drives, transmission band, drive setup, torsional rigidity
New gear-hobbing machines in which the hob and
the workpiece are turned by direct drives ensure max-
imum torsional rigidity of the generating train. The
number of original components is significantly
reduced (by a factor of 5–7), with broad standardiza-
tion of the components for machine tools of different
size and precision. Among their other benefits, such
machines have a wide range of capabilities [1–4].
At the same time, researchers have not considered
the kinematic error of such gear-hobbing machines
and its transfer to the workpiece. In the present work,
we investigate the kinematic error on a prototype of
the new generatoin 5320F4 hobbing machine for gears
of 200-mm diameter. This machine was designed at
Stankin Moscow State Technical University.
In traditional machine tools with mechanically
linked rotation of the tool and workpiece and even in
numerically controlled gear-hobbing machines with a
splitting worm transmission in the table drive, the
kinematic error of the generating train largely depends
on the precision of the splitting pair and the number of
teeth in the worm gear, which determines the domi-
nant frequency. Small margins are adopted in finish-
ing. Variation in the torque has little influence on the
kinematic error of the gear produced, which mainly
depends on the kinematic precision of the machine’s
generating train [5–9].
In Fig. 1, as an example, we present the kinematic
errors of the idling generating train according to the
Diakin-3R instrument. The accumulated error ϕ
relative rotation (the mismatch angle) of the tool spin-
dle and the workpiece is shown, as well as several high-
frequency peaks of the error. The frequency of the
cyclic error ϕ
is equal to the number of teeth of the
Fig. 1. Kinematic error ϕ
when z = 24; n
= 50 rpm.
0 60 120 180 240 300 360
, arc sec
306 312 318 324
, arc sec