NTN Corporation (hereafter, NTN) has developed an “In-wheel motor system for electric commuters” which conforms to the functions and applications in two-seater electric commuters and one-seater electric minicars, while promoting the development and commercialization of “in-wheel motor systems”.
By applying an in-wheel motor system to electric vehicles (hereafter, EV), effective use of space, flexibility in the designing of the vehicle and design can be improved. As for future expansion, this system is expected to be used in an EV for use in short driving distances for shopping and commuting, an EV friendly to senior citizens which is easy to get in and out of, two-seater electric commuters suitable for practical use in EV towns and one-seater electric minicars.
The “In-wheel motor system for electric commuters” developed by NTN, achieved a smaller size and weight reduction which can be applied to electric commuters, by changing the mechanism of the hub bearing, reduction gear and motor, which are the component parts of the already developed “In-wheel motor system”.
The in-wheel motor system, is a system where the motor and speed reduction mechanism are directly mounted to the wheel, and does not require an engine, transmission, gears, drive axles and etc. compared to internal combustion engine vehicles which is the current mainstream system. Therefore, the weight of the vehicle except for the battery can be reduced, and improves the mileage per charge (electric costs). Since the number of components can be reduced, the man-hours for assembly and maintenance of the vehicle can also be reduced, which greatly improves the flexibility of the space and body design. Compared to the current mainstream one motor type EV system, since this new system directly transmits the driving force to the tires, there is no energy loss caused by the gears, drive axles and etc., and by omitting these components, this system excels in weight reduction, the securing of the interior space and maintenance. Drive shafts are also unnecessary in the in-wheel motor system, which enables parallel movement and turning on the spot.
The world's lightest “In-wheel motor system” developed by NTN, promotes improvement and high performance of the modular products, where the in-wheel motor is equipped with a cycloid speed reduction mechanism, hub bearings and various sensors. Considering safety the top priority, reliable and stable running was realized by incorporating a system (including an inverter) which properly controls the motor driving force, based on the information from sensors.
In the development of the in-wheel motor system, various durability tests, such as submersion tests and vibration tests were repeated, in order to secure sufficient reliability during actual running.