Choosing the most suitable coupling

Which type of miniature coupling should be used for
“Motion Control” purpose?
Over a decade ago, “XH” Disk-type coupling, with all metal structure, was highly recommended because of its high torsional stiffness.
However, because of dramatic improvements in motor performances, now the best coupling to use is “XG” High-Gain Rubber type coupling.
By the combination of high vibration absorption capability and the optimum torsional stiffness, Rubber type couplings avoid the co-vibration of the system, and realize the highest performance of the motor.
Having said that, there are customers who want to continue to use the traditional types of couplings they are familiar with.
For such customers, we have “MBB” Bellows couplings, which have high torsional stiffness next to the Disk type.
And, we also have “MS” Slit couplings with simple monolithic structure.
Of course, each type of coupling I am introducing has wide range of performances based on the different size or materials.
Therefore, please note that the chart you are looking at explains the comparisons of general characteristics of coupling types,
as an “image chart”.
There is another type, as well. If you do not want to allow any misalignment and need to connect two shafts with very high coaxiality, then “XRP” rigid coupling is the most suitable thanks to its superior accuracy.