To manage the rotation speed of the electric motor, parallel to the frame and no longer transversal, BMW has chosen using the planetary gear reducer.
It is a patent that will be probably integrated on Motorrad Vision DC Roadster, which might revolutionize the sector of electric motor bikes and which concerns the motor, the transmission shaft and the overall agility that this solution would give in terms of design and efficiencies.
The new patent by BMW shows a shaft that is parallel to the frame instead of having a transversal position compared to it. This choice makes the whole motor area more compact and besides it makes use of a shaft with constant velocity joints at each extremity between the motor and the front part of the final transmission of the shaft: the motor can be positioned with more freedom inside the frame.
Moreover, electric motors turn much faster and their rotation, before transmitting the power to the rear wheel of the bike, is managed by a gear reducer directly mounted directly behind the motor, reducing the output shaft speed even keeping it in line with the main motor shaft.