The start of volume production of Schaeffler’s transmission for electric drives marks a milestone for the company’s E-Mobility business division. Developed and produced in plants in Herzogenaurach and Bühl, the transmission is available in both parallel axis and coaxial versions and offers a high input torque with low design envelope requirements.
Both variants are fitted in the new Audi e-tron. The coaxial variant provides a comfortable rear-wheel drive and selection of the parallel axis variant on the front axle enables all-wheel drive. The core of the entire system is the planetary gear set with a highly integrated spur gear differential developed by Schaeffler.
Schaeffler’s solutions for the new Audi e-tron mean the vehicle can use the electric drive system on each axle. The drive system on the front axle is an electric axle system in parallel axis design, while the rear axle has the coaxial variant. In combination with the electric all-wheel drive, the two electric machines provide impressive driving performance and agile handling.
“The entire team is proud of this innovation that we’ve developed together with Audi,” confirms Jochen Schröder, head of the E-Mobility business division at Schaeffler. “In the future, we expect a production volume of up to 250,000 transmission units per year. Thanks to the modularity of our products, we can adapt the transmission for other applications.”
Regardless of whether it is for all-electric vehicles or the hybridization of powertrains based on internal combustion engines, Schaeffler’s modular system is equipped for all requirements thanks to the new E-mobility strategy.
In addition to the acoustic optimization, the restricted design envelope of the coaxial drive architecture placed particularly high requirements on the developers. The solution to this problem is the highly integrated stepped planetary gear set combined with a spur gear differential developed by Schaeffler. Despite the axial design envelope requirement of 150mm, the transmission concept fitted in the Audi e-tron enables an input torque of 400Nm with a weight of only 16kg.
The planetary gear design concept was also applied to the parallel axis drive variant on the front axle. This approach not only reduced the development time and costs, it also optimized the quality of the product. Like the coaxial variant, this concept is also designed for an input torque of 400Nm and can be combined with an optional parking lock.
When the Audi e-tron is driven in normal traffic, the drive is via the rear axle. If more power is required for rapid acceleration, for example, the parallel axis drive system on the front axle is selected.
