A shaft and bearing model of a wind turbine gearbox has been created in order to determine the positioning of shafts and bearing arrangements which reduce the failure rate of the bearings. Shaft position is highly influential on bearing load and thus life. The bearing arrangements generally affect the stiffness of the shaft arrangement and therefore the load sharing between the bearings. A more even share of the bearing failure rate between bearings on a shaft leads to a lower overall probability of bearing failure. An investigation into the sensitivity of preload on taper roller bearings was also carried out. The preload has been used to stiffen up a shaft system and therefore reduce load on third cylindrical roller bearing which was suffering from a higher failure rate than the taper roller bearings. Bearing loads from the shaft and bearing model have then been used in a topology optimisation of the casing. This has identified the loadpaths within the casing and provided a template for a designer to then use with manufacturing and assembly constraints to generate a lightweight casing without redundant ribs.
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