A shaft coupling forms the connecting element between the shafts of a motor and the shafts of a pump and, as such, enables the transfer of mechanical work. Depending on the pump type, this connection can be rigid or not rigid. Close-coupled pumps do not feature a shaft coupling.
Rigid shaft couplings generally connect shafts that are aligned perfectly and without displacement. Among other things, this includes toothed, flange, and disk couplings. An exact installation is required to prevent misalignments form exerting too much stress on the coupling or adjacent shaft components. In contrast with it, flexible shaft couplings allow minor misalignments or shocks and are used as elastic and non-slip connecting elements. The misalignments are then compensated, for example, by means of spring elements.
On top of that, there are additional types of shaft couplings depending on the use of the pump. This includes, among other things, double-cardanic shaft couplings, which are used, for example, in chemical pumps that transport hot media. It consists of two shaft couplings with flanged-on coupling pieces.