Influence of materials on the degree of efficiency of worm gear transmission

Abstract

This paper presents the results of experimental research of efficiency of a worm gearbox which was designed for that purpose. The gearbox housing is of a welded construction with side openings, which enables simple assembly and disassembly of worm pairs, bearings and other elements. Two worm pairs with the same geometric characteristics were used for testing, where the worms are made of improved steel 42CrMo4 and the worm gears are made of zinc-aluminum alloy ZA12 and aluminum alloy A356. The values of the efficiency were determined at different operating modes of the gearbox (loads and rotational speeds), where mineral oil with a viscosity of 460 mm2/s was used as a lubricant. According to the previously defined working conditions, the power losses and friction coefficient of the worm gear pairs were calculated. Based on the test results, it is concluded that the values of the efficiency of the worm gear pair 42CrMo4/ZA12 are significantly higher compared to the worm gear pair 42CrMo4/A356, which is the result of lower power losses and lower values of the coefficient of friction.