TOKYO — In-wheel motors are a long-standing dream for electric vehicles. They hold the potential to transform car design by moving motor hardware to the wheels, freeing up valuable real estate for cabin space.
But the systems are still clunky, heavy and lacking in power. Commercialization is a long way off.
Japanese electronics giant Hitachi and its automotive unit Hitachi Astemo are now touting a breakthrough that brings this long-sought technology one step closer to reality.
Hitachi's newly developed direct-drive system reduces the weight and size of an in-wheel motor setup for EVs while also increasing its power.
The prototype combines the motor, inverter and brake in a single unit that fits in a 19-inch wheel hub and generates 60 kilowatts of power. The in-wheel setup can be arrayed in a two-motor or four-motor layout for total output of up to 240 kW, Akeshi Takahashi, manager of Hitachi's Mobility Drive Systems Research Department, told Automotive News.
The key advance is achieving a power density measured at 2.5 kW per kilogram, which exceeds the 2 kW per kilogram performance of a normal e-axle system, Takahashi said.