14 Design and Analysis of Two Wheeler Engine Gearbox through Simulation to Reduce the Development Time and Cost

An efficient design of the gearbox is crucial for the expected performance of the vehicle both in terms of life and NVH. This involves design and analysis of gears, shafts, bearings, gear layout and speed ratios. Conventionally gears, shafts and bearings are designed and analysed independently. When the design of these parts change, their effect on related parts is estimated separately, leading to loss of time. Alternately, an integrated approach through simulation is adopted for the new two wheeler's gearbox by modeling on Romax designer software, consisting of shafts, bearings and gears. For the target load cycle, gear and bearing lives, shaft deflections and stresses are estimated. While the targets for stresses, deflections and lives are set logically and with experience, these are also compared with those of reference vehicle by creating and analysing reference gearbox model. Gearbox is optimised both in terms of compactness and durability requirements apart from achieving maximum shaft stiffness and contact ratio for low noise. The prototype made as per optimised design has passed all the required tests confirming the results of simulation. Thus the new approach has lead to considerable reduction in time and cost, at the same time maintaining quality.