The presented idea is a full mechanical, magnetic and electrical design of an in-wheel brushless DC outer rotor (hub) motor. The rim of any wheel would serve as the rotor, after some modifications, for the motor. Varying rims sizes yields varying power throughput. The larger the rim the higher the output power.
A major advantage is that the entire Magneto-Motive Force (MMF) developed is utilized to drive the wheel i.e. higher efficiency overall; this was practically realized by using the rim itself as the rotor. The rim was modified to include magnetic elements and metal inserts to maximize the developed torque. Furthermore, placing the motor inside the wheels saves immense space inside an electrically driven vehicle, giving room for batteries while decreasing the required construction which simplifies the design of the whole vehicle and ultimately decrease weight allowing the vehicle to go further on a charge. This design also eliminates bulky and heavy mechanical elements (such as, differentials; drive shafts and etc.)
Outer rotor motors aren't new but they are usually used in computer peripherals (CPU Fans, Hard disk stepper motors and etc.). Also in-wheel motors are used extensively in Electric bikes (small ratings). However, the application of an outer rotor in-wheel motor in vehicles is a new concept. This motor design could be used on any electric locomotive vehicle. It could be used in electric vehicles, electric snowmobiles, inverted trikes, electric motorcycles, electric wheel chairs. Designed well, the motor could provide high power without sacrificing speed.
As all motors, the rotary motion is developed via the magnetic interaction of the magnetic fields in the rotor (rotating part) and the stator (stationary part).
The rotor is compromised of high flux magnetic inserts that are in the shape of circular sections. These inserts are held in place by a metallic ring with grooves to hold the magnets. The metallic ring not only holds the magnets in place but also helps increasing efficiency and enhancing the developed force.
The stator is located at the center of the wheel. Its magnetic circuit is compromised of copper wire windings around poles. The windings are fed with electric current to produce a magnetic field. The stator also serves as the mechanical link between the wheel and the chassis of the vehicle. Also a hub is housed within the stator to hold the wheel and rotor in place by means of bearings.
Some components are manufactured and the others are bought. The magnets placed in the rotors can be bought from numerous suppliers. The rim comes with infinite variations and also depends on the type of vehicle. The stator and the metallic ring are manufactured from CNC cut magnetic steel sheets. Layers of the cut sheets are placed on top of each other to form the laminated structure. This lamination is vital to increase the magnetic efficiency of the design as well as decreasing heat generation.