Torsional vibrations are caused by non-uniformities:
• Non-uniform drive torque
fluctuations on the drive side e.g. in the case of the internal combustion engine due to the non-continuous combustion and the crankshaft geometry.
• Non-uniform braking torque
fluctuations on the driven side e.g. in reciprocating compressors due to non-uniform forces during compression.
• Transmission error
A non-uniform transmission occurs, among other things, in the universal joint due to the geometry when the shafts are not parallel. Or due to backlash in the drive train when the direction of rotation changes or the power flow changes when the input and output sides change. In gears (gear and belt), geometrical deviations (such as eccentricity and tooth profiles) as well as deformations under load cause torque and speed fluctuations. In addition, the stick-slip effect (frictional vibration), for example, can cause non-uniform transmission.