Since the advent of the motor age, the underlying drive and the associated gear unit have formed two separate functional units, even when housed in a shared enclosure. TU Wien has now removed this separation and developed an innovative motor concept that integrates the two previously standalone units to form a single entity. Named a planetary motor by its developers, it boasts high levels of power density, energy efficiency, simplicity and reliability. The motor, which TU Wien is heralding as a world first, is now being premiered at HANNOVER MESSE 2017.
"Initially we thought about how a number of electric motors could be combined to form one unit," explains Professor Manfred Schrödl from TU Wien. Thanks to a clever geometric arrangement of several motors, some sections of the stationary motor parts proved unnecessary, which meant the entire structure could be simplified, thus saving room and reducing losses. "For example, we use four electric motors with three-phase winding, which results in twelve magnetic coils in total," says Schrödl. "However, with our machine arrangement, only six coils are needed." In this design, two drive shafts collectively power a large gear wheel with internal gearing. The other two rotors, which turn in the opposite direction, power a somewhat smaller wheel with external gearing. "This creates a situation similar to a single-stage planetary gear unit," explains Schrödl. That's how the electric planetary motor got its name. The gear unit, which we integrate directly into the motor and its output, is extremely simple, which means higher efficiency and lower production costs.