Multi-objective optimization design and reliability analysis of idler with hollow step-shaft

Abstract

Idlers, one of the important parts of belt conveyors, are substantial and constitute approximately one-third of the equipment cost. Therefore, idlers in conveyor systems must be optimized. This study designs a new kind of idler on the basis of theoretical calculation and coupling simulation, with the shaft, shell, and labyrinth gland of the idler as optimization variables and overall cost and life span of the idler as objective functions. According to each independent variable of the idler, this idler adopts the equal strength beam concept and maximizes the overall carrying capacity of the shaft and the bearing by using a hollow step-shaft. The idler effectively adopts the one-piece casting labyrinth gland, thereby automatically enhancing the sealing effect with a screw structure in different rotation directions. The simulation analysis shows that under certain working conditions, the stress of the new idler shaft is one-third of the stress of the traditional idler shaft, and the strain is one-half of the traditional idler shaft, and the effect is obvious. A reliability analysis of the idler system is described in this work through the establishment of a fault tree, determination of the logical relationship of each component and provides methods for further research. Finally, the idler is verified to be practical in engineering applications, with a 10% cost reduction and considerable economic benefits.