World’s first transmission-equipped wheel hub motor
What are in-wheel motors?
In-wheel motors are next-generation drive technology, that places motors in automobile wheels.
Advantages of in-wheels motors
This technology improves automobile safety, environmental impact, and driving comfort.
A. Safety: improved maneuverability
B. Environment: Reduced energy consumption
C. Comfort: Increased vehicle cabin space
Issues faced by in-wheel motors
A great deal of motor miniaturization research in taking place, but motors with sufficient drive performance have been too large, and commercialization has yet to be achieved.
NSK’s wheel hub motors
NSK”S wheel hub motors achieve driving performance targets while reducing motor size. Lets’s look at how this is accomplished.
Transmission system <Hight gear>
NSK’s wheel hub motors use two motors, (Motor A, Motor B) both rotating in the same direction for high gear operation. When motor B’s rotation direction switches a one-way clutch stops the planetary carrier, switching from high to low gear.
Transmission system <Low gear>
One-way clutch, Planetary carrier
Final speed reduction system
A hub unit bearing with a built-in speed reducer delivers the torque the wheels, using a sun gear, pinion gear, and ring gear integrated into the hub unit.
This transmission mechanism makes it possible for small motors to provide a large amount of drive torque and sufficient maximum speed.
Low Gear acceleration
Low gear provides faster acceleration than high gear.
After starting in low gear, the motor switches to high gear and accelerates until it reaches maximum speed. Use of this transmission improves operating efficiency to increase driving range. Wheel hub motors can used independent of vehicle body structure, so they can be used with evolving drive types such as HEVs, EVs and FSVs. NSK is continuing to develop products that contribute to the future of automotive technology.