Faculty of Forestry and Wood Technology, University of Zagreb
Abstract
The aim of this study is to check the possibility of replacing the pinion gear made of structural steel with the one made of sintered material. The pinion is part of the gear pair mounted in front of the gearbox of the skidder Ecotrac 55V to increase the speed and lower torque. In larger series, powder metallurgy (PM) gears are used as a cost-effective alternative for wrought metal gears in a number of industries including the one producing forest products. The present paper discusses the computational and experimental approach for determining the service life of sintered PM gears in regard to tooth bending fatigue. The proposed computational model is based on the stress-life approach, where the stress field in a gear tooth root is determined numerically using finite element method. The needed material data have been taken from the authors’ previous work. Due to the scattering nature of fatigue, the statistic approach has also been considered by presentation of computational results. The experimental procedure was done on a custom made back-to-back gear testing rig. The comparison between computational and experimental results has shown that the proposed computational approach is an appropriate calculation method for estimating the service life of sintered gears regarding tooth root strength. Namely, it has been shown that, in case of proper heat treatment of tested gears, tooth breakage occurred in the interval with 95% probability of failure, which has been determined using the proposed computational model
