Failure Cause Investigation of Worm Wheel used in Crate Washer Gear Box

Abstract

The “Kolhaupur Zilla Sahakari Dudh Utpadak Sangh Ltd.”, Kolhapur, Maharashtra, a milk processing industry uses reduction gear box for driving conveyor belt assembly of crate washer setup used to clean the crates used for storage and transportation of milk pouches. A mentioned setup experiencing a problem of tooth failures of worm wheel used in its gear box. The motor used to drive the worm has power of 2.23 kW & speed of 1440 rpm. The speed reduction is 50:1. By studying failure pattern of damaged worm wheel teeth, excessive wear and bending fatigue are proved to be the basic reasons for gear teeth failure. The present study deals with the detailed analysis and evaluation of excessive bending stresses induced in teeth of worm gear using theoretical and experimental method. Theoretical evaluation of bending stresses in worm gears was carried out using Lewis equation and photo stress method is used for experimental stress analysis. As a result of this study, improper selection of geometrical and material parameters of worm and worm wheel for this particular application is proved to be the basic reason for failure. So, worm and worm wheel are redesigned theoretically by changing their geometrical properties and material as per required working conditions