This configuration offers some very
Tilting and torsional stiffness are high,
significant advantages over other gear
leading to precise positioning and high
layouts. For instance, all the parts fit inside
repeatability. In fact the Melior Motion
the ring gear making it a compact unit.
was designed with robot applications very
Because there are a number of planet
much in mind, hence its compact size, low
gears, there are many teeth meshing with
maintenance, and high performance.
one another, each pair transmitting power
In conclusion we can say that planetary
and adding together to give a high torque
gearheads are enabling more and more
capability in a compact unit.
potential users to think about adopting
The multiple meshing of teeth also helps
precision servo drive technologies for their
to significantly reduce backlash compared
machines and systems. First time users
to a gear system where there is only one
in particular may appreciate technical
meshing pair. Also, because the power
support from a company like Drive Lines,
transmission is spread equally across each
which not only supplies gearheads and
planet gear, there is an innate symmetry
associated equipment but also has a
which helps prevent the gearhead from
flexing under load.
Thus it can be seen that planetary
gearheads have a lot to attract designers
of precision drive mechanisms. They are
wealth of expertise and experience in
Now to look in more details at a particular
specifying precision drives for a wide
planetary offering, let’s take the Melior
range of applications.
Motion range, again from Premium
Stephan.
Established over 30 years ago, Drive Lines
has worked on applications as diverse as
compact, powerful, accurate and robust.
This has many design details that help
hot drape formers, golf buggies, lifting
In order to make planetary gearheads
ensure performance is as precise and
systems, laboratory equipment, cement
even more attractive to potential users,
reliable as possible. For instance, the
mills drives and a door closure for a
manufacturers such as Premium Stephan
gear teeth have a unique profile that
medieval cathedral.
make them in a range of formats, so that
guarantees backlash is less than 0.6
individual requirements can be met from a
arcmin and will not change by more
standard model or one that has been only
than 10% over the nominal operating
slightly modified.
lifetime of 20,000 hours. This reduces the
Premium Stephan can supply their
gearheads as sub-assemblies, enclosed
costs associated with initial set up and
subsequent servicing and replacement.
If the sun gear is turned, the
gearboxes or fitted to a motor to form a
Further, the Melior Motion’s torque
meshing teeth cause the
unitary component. They are available in
capacity is exceptional for such a small
planet gears to turn, which
a range of sizes and can be supplied with
footprint, so energy efficiency is high. Thus
then cause the ring gear to
either solid shafts (with shaft length to
heat generation is low, allowing standard
turn. It sounds complicated
match the application) or hollow shafts,
lubricating oils to be used rather than
and looks hypnotic, but in
the latter allowing a feed-through of
expensive specialist ones. It also leads to
fact is very simple. It is also
cables. Generally they are designed for
low starting torque, inertia and braking
notable that the ring gear
use with standard mineral oils, although
loads, and therefore smooth and reliable
turns in the same direction
specials are available.
operation.
as the sun gear.