Schaeffler is one of the innovation drivers with answers for the technological challenges of the mobility of today, tomorrow, and beyond. At eCarTec, the company is presenting a broad cross-section of electric mobility products in Hall A6 from October 18 – 20, 2016. “Our innovative solutions from the E-Clutch to the electric axle, from our STEP² concept vehicle to the electric wheel-hub drive clearly show that we at Schaeffler are able to make decisive contributions towards the development of mobility for tomorrow – from basic components all the way up to the complete system,” says Prof. Dr.-Ing. Peter Gutzmer, Deputy CEO and Chief Technology Officer at Schaeffler.
Schaeffler STEP² Concept Vehicle with a Two-speed Electric Drive
Efficiency and dynamics represent the driving force for Schaeffler engineers when combining the electric drive and transmission. The STEP² concept vehicle is an entirely electric vehicle with a two-speed powershift transmission. “By shifting between two gears – a short gear ratio for a high traction force and a long gear ratio for good overall efficiency levels even at higher driving speeds – it is possible to improve dynamics and electric range at the same time,” explains Uwe Wagner, Vice President R&D Automotive at Schaeffler.
Compared to a similar vehicle with only one speed, the STEP² attains a clear consumption advantage of around six percent. The basis for the STEP² is a large series compact class vehicle. The electric motor is from the Schaeffler product brand IDAM. The transmission consists of a planetary gear set, a wet multi-disk clutch, a band brake, and a lightweight differential. Power shifting is used to change gears, with the “coming shift element” (e.g. the clutch) taking over the initial torque from the “going shift element” (e.g. the brake). It is only afterwards that the speed is adjusted. The upshot of this is that the drive torque supplied is constant even during the shifting process, resulting in a gear change that is comfortable and without an interruption to the traction force.
Schaeffler Wheel-hub Drive – Enabler for Innovative, New Vehicle Concepts
With its E-Wheel Drive electric wheel-hub drive, Schaeffler is setting its sights on completely new vehicle concepts of the future and offering a very promising approach for the mobility of tomorrow. “For us, the E-Wheel Drive is an enabler for new space-efficient concepts for future vehicles and thus a key to fulfilling the needs of urban mobility,” explains Gutzmer. This also goes along with the increasingly important topic of highly-automated driving.
Integrating the electric motor, power electronics, and the control unit directly into the wheel provides new degrees of functional freedom and significant installation space advantages over conventional drive concepts.
Stated in technical terms, it is a permanently excited synchronous motor without a transmission unit, making high power density possible in an extremely compact package. Naturally, the recuperation of deceleration energy is also part of the performance range of this electrical drive system. In addition to efficiency, the drive system also offers advantages with respect to driving dynamics. The torque that is constantly available to the complete system is 500 Nm, with a peak torque of 810 Nm for each drive system. An integrated drum brake corresponds to current production standards – just like the link to conventional axle architectures and wheel rims, which also makes it possible to replace the tires without difficulty, the same as for any other production vehicle.
