The dynamic balance of a coupling refers to the state of the centrifugal force that deviates from the transmission shaft systems at both ends during the operation of the coupling. The precision index of the dynamic balance of the coupling must be strictly controlled.

The dynamic balance accuracy index of couplings is stipulated by different standards according to different types of couplings. The manufacturing of this type of coupling requires the coupling manufacturer to use forged materials (with corresponding heat treatment) for overall processing as much as possible to avoid the centrifugal force deviation effect caused by the internal structure defects (pores, sand holes) of cast steel materials.

The dynamic balance index of couplings can be detected and balanced on a dynamic balance testing machine, for instance, the overall dynamic balance test of large intermediate shaft type drum gear couplings, etc. However, the key reason for the dynamic balance accuracy error of couplings lies in the manufacturing precision of the couplings, such as the selection of material types (the difference between forging materials and casting materials), the contact accuracy between coupling accessories (pins, connecting bolts, diaphragms) and the coupling body, and the improvement of the contact accuracy of each part of the coupling connection is a measure to enhance the dynamic balance accuracy of the couplings. For instance, The contact state between the elastic pad of the XL star-shaped elastic coupling and the two half couplings is different. As a result, the centrifugal force state generated during medium and high-speed operation is also different (reflected in the generation of noise and the different smooth states of the transmission shafts at both ends).