Effect of Rim Thickness on Load Sharing in the Rotating Elements

The aim of the study is to obtain an optimal arm section for the structures like pulleys, gears, flywheels etc. considering variation of rim thickness with pulley radius. Presently, the design of arm pulley with thin rim is being carried out with an assumption that the bending moment (BM) is shared by half the number of arms, whereas in case of arm gear or V-Belt pulley the assumption is made that BM is shared by total number of arms. In the present paper, Finite Element Method (FEM) is used to determine the BM shared by the arms for its different angular positions. The distribution of bending stress in the arms is also obtained. Finally, design modifications have been suggested considering radius to rim thickness ratio (r/t). Hence it is concluded that when, 15 ≥ r/t > 10.5 – BM is shared by N/2 number of arms, 10.5 ≥ r/t > 7.5 – BM is shared by 4N/7 number of arms, 7.5 ≥ r/t > 5 – BM is shared by 2N/3 number of arms, 5 ≥ r/t > 3 – BM is shared by 4N/5 number of arms, 3 ≥ r/t –BM is shared by N number of arms.