Military tracked vehicles demand a very compact transmission to meet mobility requirements. A compact transmission with low operating noise and vibration is desirable in military tracked vehicles to reduce weight and improve power-to-weight ratio. It is also necessary to increase the rating of existing transmissions in military tracked vehicles, like prime movers, to accommodate the additional weight required for ballistic protection. Hence, it was decided to apply a high-contact-ratio (HCR) spur gearing concept that will reduce noise and vibration and enhance load carrying capacity for a 35-ton, tracked vehicle final drive. In HCR gearing, the load is shared by a minimum two pairs of teeth, as in helical gears. It was decided to analyze the load sharing of the normal-contact-ratio (NCR) gearing used in the sun/planet mesh of the existing final drive; and, to analyze the load sharing of the HCR gearing that will be used to replace the NCR gears without any change in the existing final drive assembly except sun, planet and annulus gears. This paper deals with analysis of the load sharing percentage between teeth in mesh for different load conditions throughout the profile for both sun and planet gears of NCR/HCR gearing - using finite element analysis (FEA). Also, the paper reveals the variation of bending stress, contact stress and deflection along the profile of both NCR and HCR gearing.
展开▼
