C
L E A R
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A T H
M C / S D
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A N U A L
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E V
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3 . 0 9
1 6 5
T
EKNIC
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I
NC
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EL
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(585)
784-7454
N
OTES ON
C
OUPLING
S
ELECTION
A complete coverage of the topic
Coupling Selection for Servo
Applications
is beyond the scope of this document, but many articles and
resources can be found on the web for those interested in learning more.
Because there are so many different coupling styles and applications,
selecting the “right” coupling for a particular application can be
challenging.
General Guidelines for Coupling Selection
Teknic has a few guiding principles when it comes to coupling selection
for servo applications. Keep in mind that these are rules of thumb and
may not apply to every application. In general:
•
Don’t
undersize the coupling. Understand how much torque
your application requires and stay within the coupling
manufacturers specifications. Always leave reasonable
engineering margin.
•
Don’t
use set screw type couplings. They damage the motor
shaft and tend to be less reliable over time than clamp style
couplings.
•
Do
use clamp style couplings. These clamp around the
circumference of the shaft at one or two points without
deforming the shaft surface.
•
Don’t
use rigid couplings—they are notoriously intolerant of
misalignments.
•
Don’t
use beam style (helical) couplings if vibration damping
or torsional stiffness is critical to your application. Beam
couplings tend to resonate/whine at higher speeds.
•
Don’t
use any coupling that requires you to drill into, deform,
or “pin” the motor shaft.
Coupling Recommendation
Teknic often recommends
zero-backlash curved jaw couplings
(commonly referred to as “spider couplings”) as a good choice for many
servo applications. These couplings are moderately priced and widely
available from well established manufacturers such as Ruland.
Couplings for servo applications
Note:
Curved jaw couplings (also known as spider couplings) are a good
choice for many applications, but cannot tolerate a great deal of
misalignment or axial motion. Also, never exceed the manufacturer’s
rating for “maximum torque with zero backlash” when using jaw
couplings.
