Bellows couplings offer a high level of
accuracy and are ideal for camming, indexing,
reversing and positioning. The flexible element is
a formed stainless steel bellows, which exhibits
two beneficial characteristics: high torsional
stiffness, and continuous symmetry. Two hubs
are connected to the bellows via adhesive,
clamping rings, or welding.
This type of coupling works well in dynamic
applications because motion is transferred
with zero backlash and a high level of stiffness,
resulting in very short settling times and
minimal torsional wind-up. This stiffness also
helps to minimize rotational positioning errors,
along with the continuous symmetry of the
bellows, which allows for true constant velocity
output rotation, even when misaligned.
The right coupling can improve performance and help avoid operational problems throughout a machine’s life. When pairing
a coupling with a servo gearbox, many things
should be considered, including whether the
coupling is intended for highly dynamic, high
precision motion, or simply for smooth running
and efficient acceleration. The potential for torque
overload should also be considered. Additionally,
while mechanical overload protection is often
categorically disregarded in modern servo drive
applications, it is actually a valid and useful
technology when considering recent advancements.
Though often overlooked or left to the last minute, coupling selection for a new
precision gearbox application can be a crucial step in the design process.
By Leon Voskov, R+W America
Coupling Considerations for
Servo Gearbox Applications