A common observation among epicyclical gearing system designers is that the bearing rating of each planetary idler represents one of the major limitations to increasing the power rating of a gearbox. Another limitation is the inherent misalignment imposed inside the gear meshes and bearings by the torsional wind up of the planetary carrier. To accommodate these conditions, designers often resort to using systems consisting of three planetary idlers with larger aspect ratios and thinner rims than desired. This conventional approach does not usually balance the bearing and gear capacities, so maximum power density is rarely achieved.

To solve these problems, Timken has developed two new integrated bearing solutions – Planet Pac™ and the integrated flexpin bearing - that increase bearing capacity and improve performance.