A coupling initially connects two shaft journals. However, even a minimal offset of the shafts or fluctuations in the ambient temperature can lead to uneven running.

Bellows couplings are very torsionally rigid in the direction of rotation, i.e. they hardly twist on themselves. Laterally, on the other hand, they are flexible, which allows them to compensate for misalignments. Low restoring forces, absolutely backlash-free torque transmission and flexible application options make them an indispensable component in mechanical engineering today. Metal bellows couplings are particularly suitable for high speeds and precise applications.

Select the right servo coupling

Safety coupling SKB-KP with special cut. © Jakob Drive Technology

Elastomer couplings have a damping effect on vibrations instead of passing them on to the next component. With this type of compensating coupling, it is also important to ensure the most precise alignment possible, but the risk of damage is much lower. Depending on the application, combinations of metal bellows couplings, safety couplings, elastomer couplings and spacer couplings are also possible.

To find the right servo clutch for a specific application, it is important to first determine the required maximum torque. The coupling should then be selected accordingly, as it must never operate permanently with an overload or in the absolute limit range. A possible misalignment goes hand in hand with the possible service life, because the greater the misalignment, the greater the wear and the shorter the life expectancy of the clutch. It is therefore essential to ensure that the alignment is as accurate as possible. The compensable lateral misalignment ranges from around 0.15 to 0.3 mm. This also depends heavily on the number of bellows shafts. For example, a four-shaft coupling achieves several times higher possible misalignment values than a two-shaft coupling.

Safety clutch SKY-EK in section. © Jakob Drive Technology

In principle, however, lateral displacement is one of the most important factors to consider after torque, as it has a major impact on possible power transmission. As mentioned above, a high offset can also lead to uneven running and thus to increased wear, greater noise generation or even damage to the entire drivetrain.

When measuring the maximum operating temperature, it is also important to take into account any heat generated by the machine and its components during operation. The choice of material for the couplings is also important in this context. Aluminum, which is often used due to its low weight, is replaced by stainless steel components at very high maximum temperatures, for example.

According to documents from Jakob Antriebstechnik / am