A piston engine runs unevenly. Something has to stand between it and the driven machine to take that unevenness up.
A combustion engine does not deliver its torque evenly but in firing impulses. Couple it rigidly to a driven machine and torsional vibration runs through the whole train. The coupling damps it – and for that it usually sits directly on the flywheel.
Mounting goes through the engine's flywheel. Its size in inches and the bolt circle of the drive plate decide which coupling size fits.
The softer the coupling, the lower the natural frequency of the train – and the more likely the operating range lies above it rather than in resonance.
What counts is the engine's rated moment together with the service factor, not the shaft diameter.
A catalogue sheet of its own with 48 combinations of coupling and flywheel size. The designation names both, for example “012 E 11½ V” for size 012 E on an 11½-inch flywheel.
Source: catalogue sheet “Kado couplings for combustion engines”
The sheet assigns a coupling size to nineteen three-phase motors to DIN 42 673 from 0,75 to 132 kW – with shaft end, rated moment and slipping torque.
Source: FLEXAN catalogue sheet, assignment to the motor
For drives with a high damping requirement. The sheet gives the dynamic torsional stiffness for natural rubber and Perbunan as well as the resonance factor.
Source: Kegelflex catalogue sheet, selection data
That we supply this sector is information from the management, 13.10.2026. Why a range suits a load case is in the catalogue sheets; the place is named for each range.
We will get back to you shortly – with a person who knows the engineering.
