Yamaha has filed a number of patents with the U.S. Patent and Trademark Office and the European Patent Office for an electric three-wheeled scooter. Unlike the Yamaha Tricity which has two wheels at the front and a third wheel at the rear, the patents are for a scooter with two rear wheels, each driven by an electric hub motor.
The two patents are for two separate processes for the same electric three-wheeled vehicle and its leaning mechanism. The USPTO patent puts more focus on how to minimize the increased weight of a third wheel and battery while the European patent focuses on the electric motor controller.
The scooter illustrated in the patents’ diagrams resembles the Yamaha EC-03 electric scooter currently on the market in Europe. The vehicle in the diagrams shares an identical front end, frame, and seat as the EC-03. The battery is also stored in a similar location beneath the seat.
What’s different is the second rear wheel, a second swingarm, and a complicated system that allows the vehicle to lean. The two swingarms pivot around the same axis (identified by the line A1 in Fig. 5 below). The swingarms each extend downward from the pivot point where they each connect to a rod (45L and 45R) which are connected to a rocker arm (43).
The rocker arm rotates when the vehicle leans, causing one swingarm to rotate up relative to neutral while the other rotates down. Fig. 6, below, illustrates a lean to the right. The rocker arm pushes the right rod back which causes the right swingarm to pivot upward. At the same time, the left rod is pulled forward, causing the left swingarm to go down.
The rocker arm is connected to the rear suspension system which runs a shock under the scooter. This allows the entire rear tilting mechanism to pivot up and down to handle bumps in the road.
Yamaha has previously announced it would introduce more leaning multi-wheeled vehicles, but the assumption was they would all be variants on the Tricity and its parallelogram link tilting mechanism, but these new patents indicate Yamaha is considering other methods of making three-wheeled vehicles tilt.
What’s less clear is whether we’ll see Yamaha turn these patents into a production model. We know Yamaha is working on several leaning multi-wheelers like the Tricity and a sportier-looking variant we recently uncovered in Japanese patent filings. Before the Tricity, Yamaha had been toying with other leaning multi-wheelers, most famously with its four-wheeled Tessaract concept. Tusjii Eiichirou, one of the inventors listed in the USPTO patent, and Nobuo Hara who is listed in the European patent, have both worked on patents for other Yamaha leaning four-wheeled vehicles that never made it to production.
If Yamaha does produce this vehicle, it would be designed for short trips and delivery services much like the EC-03. Referencing the diagram above illustrating Yamaha’s leaning multi-wheeler strategy, the scooter would fall into the utility and commuting quadrant in the bottom left.
[Source: USPTO, European Patent Office]