Calculation and Selection of Fits for Joints of a Combined Elastic-Bushing Finger Coupling

This article discusses the features of using elastic bush–pin couplings. Calculation and selection of fits is presented for the case of using elastic bush–pin coupling halves of different designs with different diameters of landing holes. The connection between the shaft of an A280S8 electric motor and the shaft of the WVP’1-25 vacuum pump with an elastic sleeve-pin coupling was chosen as the object of research. It has been found that the electric motor shaft connection with a $$\emptyset $$ 80 mm coupling during assembly using the pressing-in method should be assigned an H8/t6 fit, and when heating the coupling, H8/t7. To connect the shaft of WVP’1-25 vacuum pump with a coupling of $$\emptyset $$ 65 mm, for any type of assembly, one can assign an H8/t6 fit, in which the maximum tension is four microns higher than the maximum established limit of technological tension, which can lead to destruction of the cast iron coupling. In this regard, it is recommended to the coupling manufacturer to increase the equipment accuracy in order to provide a fit for the connection of the vacuum pump WVP’1-25 shaft with a coupling of $$\emptyset $$ 65 mm in the form of H7/t6, which will meet the calculated accuracy requirements.