GN 2244 Bellows Couplings with Clamping Hub

Like all mechanical parts, shafts are subjected to manufacturing and assembly tolerances that generally cannot be entirely eliminated even with extensive technical measures.
If these deviations are not taken into account in the design, the result can be vibrations, running noises, and wear or damage to the shafts and their bearings.
Suitable couplings not only are able to effectively compensate for misalignment and runout errors, they also greatly simplify the assembly process, thereby reducing the overall labor required.
Shaft misalignment and runout errors can vary in nature and should always be taken into consideration when selecting the appropriate coupling.

Error type

Misalignment diagram

Lateral
The axes of the shafts are in fact parallel, but they are offset laterally and do not line up.

Angular
The axes of the shafts do not lie in the same plane; they meet at a certain angle.

Axial
The shafts move axially along the axis of rotation.

Runout
The shafts move radially out of the center of the axis of rotation.

For correct fastening of the coupling hubs, the shaft must be installed according to the recommended shaft insertion depth l₂. The shaft insertion depth l₂ is specified in the standard sheet of the respective coupling.
If the insertion depth is too low, the shaft could slip out of the coupling, or the clamping hub could break. If the shaft is inserted too far, this can cause interference within the coupling, leading to damage.

The diagrams show the change in static torsional stiffness within the permissible operating temperature range, under the assumption that the static torsional stiffness at 20 °C is 100 percent. The torsional stiffness of the couplings decreases with increasing temperature.

When the shaft ends are installed in eccentric arrangements, the coupling constantly attempts to return to its neutral position. The resulting force is referred to as restoring force.
If the couplings are installed with the lowest possible eccentricity, the resulting restoring forces are lower. This also reduces the force acting on the shaft bearing.

If the coupling is under pressure, subject to compressive load in the axial direction, it will strive to return to its neutral position. The force that counteracts the compressive force is referred to as restoring force.
Lowering the compression acting on a coupling results in a lower restoring force and less force exerted axially. This must always be taken into account in dimensioning the coupling.