Standardized calculation methods such as ISO 6336 and DIN 3990 already exist to determine the load distributions on gears inside a planetary gearbox, but by their very universal nature, these methods offer varying results depending on the gearbox design. Double helical gears, in particular, can benefit from more specific, complex algorithms to reach a maximum level of efficiency. Double helical gears interact with the rest of the gearbox differently than helical or spur gears, and thus benefit from different analytical models outside the standardized methods. The present research project describes the algorithm to determine the load distribution of planetary gearboxes with double helical gears.

This paper presents a joint project conducted by Ashwoods Electric Motors and Oerlikon Fairfield that uses planetary drives with an integrated electric motor. Current solutions used in production of off-highway vehicles rely upon large, heavy and inefficient brushed DC or induction motors, coupled to a planetary gearbox. This presents a number of challenges to the vehicle designers such as: limited vehicle range, limited space around the motor/drivetrain, and motor durability. The proposed integrated system utilizes an Oerlikon Fairfield Torque Hub, widely used in off-highway vehicles, and the Ashwoods first-to-market, interior permanent magnet motor. How these products are integrated, i.e. incorporating a brake solution, represents a market-changing product. Using interior permanent magnet (IPM) technology in the motor design means the motor can be up to 70% lighter, 70% smaller and 20% more efficient than traditional motors used in off-highway traction applications.