ZF integrates electric drive in new modular rear axle system
July 7, 2017
The fully modular ZF mSTARS-System, combining axle, drive and intelligent chassis: The whole electric unit is shown here integrated in the centre of the axle carrier, along with AKC tracking alignment for active rear-wheel steering control (Courtesy ZF)
ZF Friedrichshafen AG, Germany, has incorporated a 150 kW electric motor in its mSTARS (modular Semi-Trailing Arm Rear Suspension) axle system. The innovative system will reportedly make it easier to electrify volume production vehicle platforms, including for existing vehicles as demonstrated in the company’s Vision Zero Vehicle.
“mSTARS provides our customers with a basis for a wide range of applications in multiple vehicle segments. The solution is suitable for hybrid, fuel-cell and battery-powered vehicles as well as in combination with conventional all-wheel modules or our AKC active rear axle steering,” explained Dr Holger Klein, Head of ZF’s Car Chassis Technology Division. “The Vision Zero Vehicle demonstrates how quickly it could help the industry meet the challenge of producing high-performance e-cars or hybrids.” The system may offer vehicle manufacturers the opportunity to respond to a diverse range of market requirements using just one car platform variant.
In the Vision Zero Vehicle, which is based on a volume production platform for compact and mid-size cars, the mSTARS semi-trailing link independent suspension reportedly takes up no more installation space than the conventional rear axle. ZF’s new system uses a unique integral link design and separate spring damper configuration, giving it the potential to free up installation space between the rear wheels allowing ZF’s electric drive to fit easily into the mSTARS system axle carrier.
As well as the electric motor, the 150 kw drive unit houses a two-stage one-speed spur gear drive, a differential, and power electronics along with control software. “We’ve put our concept of an intelligent mechanical system and clean mobility into this multifunctional axle system for compact passenger cars and up,” stated Dr Klein.
According to ZF, the mSTARS axle also boasts a high level of driving dynamics and safety – delivering the performance of more expensive, conventional multi-link axles typically used for compact premium and sports vehicles. ZF’s AKC active rear axle steering system, which can be combined with any modular axle configuration, is stated to improve agility, comfort and stability.
mSTARS is ZF’s response to the key industry megatrends, the company stated. The new rear axle system not only plays a role in zero-pollution driving but also in improved safety, thus helping to bring the company closer to its Vision Zero, of an accident and local emission-free future.
