Transmission specialist Oerlikon Fairfield co-presented details of an innovative electric drive system for off-highway vehicles at the recent VDI
International Congress in Friedrichshafen, Germany. The system integrates an Oerlikon Fairfield Torque Hub planetary drive with an Interior Permanent Magnet Motor produced by Ashwoods Electrical Motors, to create an ultra-compact drive solution that is up to 70% smaller and lighter and 20% more efficient than traditional motors used in off-highway traction applications.
“The improved efficiency, small package size and competitive cost of this integrated solution sets a new benchmark for electric drives in the off-highway sector,” explains Gunnar Stein, Chief Technical Officer of Oerlikon’s Drive Systems Segment. “The unit is so compact that it enables vehicle manufacturers to provide a steerable four-wheel-drive configuration where previously there was not enough space to offer
The complete unit can deliver 4,000 Nm of drive torque and 5,600 Nm of braking torque, yet the motor is up to 70% smaller and lighter than current production solutions that use larger, less efficient brushed DC or induction motors coupled to a planetary gearbox. The Oerlikon Fairfield/Ashwoods Electric Motors solution provides a triple planetary ratio in the length of the standard double planetary design.
Combining the two technologies with an integrated Ultra electric parking brake has enabled the elimination of several duplicated or redundant components; for example, a common shaft is used for motor, brake and transmission. This approach saves weight, cost and package space.
The Oerlikon Fairfield Torque-Hub planetary drive is already well-proven and widely used in off-highway vehicles and is available in single planetary, double planetary, triple planetary and differential planetary gearing configurations to meet the individual torque and operating speed requirements of different applications.
Dynamometer testing of the new drive system has been completed and durability tests are in progress; vehicle-based testing is scheduled to begin at the end of June 2016.