this patent contains two transmission modes, which are shown in cross section. In the first type, the motor is placed in the center, and the universal joint connecting rod is used to transmit power to the drive shaft, and then the rear wheel is driven through the gear set. This way helps to reduce the volume of the car body and balance the center of gravity. BMW Vision DC Roadster motorcycle is expected to adopt this driving mode.
the second method also uses a universal joint, but the motor is placed off the center line and in the same line as the drive shaft. This method is beneficial to improve efficiency and reduce wear, but the disadvantage is that the motor occupies too much volume and needs additional counterweight to balance the center of gravity.
It is also pointed out in the patent that the BMW electric motorcycle has a planetary gear set in the rear wheel for speed change and makes the motor work in the best working condition. As can be seen from the real shot of Vision DC Roadster, the rear wheel of this motorcycle can swing up and down for shock absorption, so it needs a universal joint to drive the motorcycle. The brake disc of motorcycle is in the same direction as the drive shaft. The car body is made of carbon fiber connecting rod.
IT house has learned that BMW Vision DC Roadster electric motorcycle adopts lightweight design, and its body is made of aluminum alloy and carbon fiber, with a battery capacity of 12.7Wh and a battery life of 159 kilometers. If this car can be mass-produced, it will become the world's first electric motorcycle driven by a transmission shaft.