POWER DEPENDENCES OF THE TORQUE IN THE OVERLOAD COUPLING WITH STAR-SHAPED SPRING WITH STRANGULATED ENDS OF VERTICES

The article examines the structure of an overload flexible coupling that contains internal and external hubs, connected by a star-shaped spring with the circular vertices inserted in grooves on the outer surface of internal hub and inner surface of the external hub. Position of the star-shaped spring is fixed on the inner hub by the wedge with screw, which allows the spring to be made solid or made up of separate circular vertices with strangulated ends. The working principle of coupling is described as follows. During the rotation of inner hub, torque is transferred to the outer hub through star-shaped spring and grooves. In overloading mode, star-shaped spring starts deforming, decreasing in diameter along its outline, with grooves being compressed, within the elastic deformation range, and slipping out of the external hub grooves, which curves radius is larger than one of spring edges, and sliding on the surface of an external hub until torque is over the nominal value. We have conducted a geometric synthesis of star-shaped spring with vertices of circular shape, depending on its size. It had been assumed that star spring vertices are the double-hinge arches of circular form and we conducted calculations of analytical solutions using the methods of structural mechanics. Analytical expressions obtained allow drawing conclusions about workability of the star-shaped spring of flexible overload coupling during the torque transmission.