Development of a new transverse flux motor

A conventional drive system for electric vehicles consists of the motor, a reduction gear and a differential gear to transmit the torque to the two driving wheels. The gears increase costs and weight, and the axle required between the wheels obstructs the free layout of the drive components. These shortcomings can be avoided, if the motors are gearlessly attached to the wheels. This requires a high output torque. Compared to conventional designs, the transverse flux concept has favourable characteristics concerning specific torque and efficiency. For this reason it seems to be especially suited for direct drive applications. Despite its good characteristics the transverse flux machine has not yet met with much interest for line production, because the well known double-sided designs presented up to now are too complicated to manufacture. The main target of our development described in this paper was therefore a transverse flux motor, which has a high specific output power, is easy to manufacture, has a high utilisation of the magnetic material and needs only a conventional inverter. This is important for the costs of the machine