SEED Guides Unit Selection - Shaft Coupling < >

If the axes of the shafts to be coupled are truly co-linear and will remain so throughout their operating life then a rigid coupling can be used. However in many cases such concentricity is not present and/or some slight misalignment may occur during service. Then a flexible coupling must be used.

Figure 2 shows the four conditions requiring a flexible coupling. They are:

º angular misalignment (AM)           º parallel misalignment (PM)
º end float (EF)                             º torsional flexibility (TF).

Misalignment can be caused by any combination of the following:

º tolerance build-up during assembly              º shaft deflections
º lack of integrity in the mounting (settling)     º unequal support deflections
º temperature changes                                  º bearing wear
º shock loads                                               º vibration.

If torsional shock and/or vibration are present then a torsionally flexible coupling is required.

Figure 3 shows a classification of coupling types.