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,” explained 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 this possibility.”
The complete unit can deliver 4000Nm of drive torque and 5600Nm 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 offhighway 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.