Source: Hitachi,Ltd. and Hitachi Astemo, Ltd. announcement
Tokyo — Hitachi, Ltd. and Hitachi Astemo, Ltd. have jointly announced the development of a compact, lightweight direct-drive system for the increasingly popular EV segment, which combines the motor, inverter, and brake into a single unit.
This enables the installation of the entire system into the wheel, thus moving the world one step closer to a zero-emissions society.
The new motor transmits the high drive force necessary to run an EV directly to the wheels, and its lightweight design and world-class 2.5 kW/kg power density significantly limit the weight increase traditionally associated with in-wheel units.
Moreover, adopting an in-wheel unit does not require a substantial change to the existing configuration of the suspension and other components.
Driveshafts and other indirect mechanisms have been eliminated, allowing motor power to be applied directly to EV operation. This reduces energy loss by 30 percent and increases the range on a single charge compared to existing EVs.
Hitachi and Hitachi Astemo will continue research into practical implementation of the technology, which enables more expansive interior and battery installation spaces. In addition to the vehicle-control technology it has been developing, Hitachi Astemo will apply the new direct-drive system to its already-extensive, global EV product lineup.
Background and additional information
There is growing investment activity and technological development towards realizing a decarbonized society. In the motor vehicle sector, there is an especially strong legislative push for transitioning from gasoline-driven vehicles to EVs.
In conventional EVs, the drive system is placed on the chassis, which limits interior and/or battery space. Fitting the motor inside a wheel has been identified as a solution, but this increases the weight in the wheel and requires sweeping changes to the existing brake and suspension components.
To address this, Hitachi and Hitachi Astemo’s lightweight direct-drive system-drawing on Hitachi Group’s broad technology and product development in the mobility space that includes railways and elevators-combines motor, inverter, and brake into a single in-wheel unit for EVs. The features of the technology are as follows:
To view the entire announcement with images, click HERE.