Why is ebike spoke wheel hub motor so widely used?
 2021/02/19 | View:1040

A ebike spoke wheel hub motor is a motor assembly with an integrated gearbox assembled directly into the wheel hub.

The definition of ebike spoke wheel hub motor may seem a bit strange or even mysterious to you. In fact, hub motors are not a new technology, they have been around for over 100 years and are still widely used. It's just that it's not used in cars, but in electric bicycles, which we all take for granted.

Note the rear wheel of the e-bike above, which is driven by a one-piece sealed hub motor. Most of the electric bicycles on the market are driven by this rear wheel hub motor. Why is ebike spoke wheel hub motor so widely used in electric bicycles, but rarely used in cars? The reason is that e-bikes are two-wheeled, while cars are four-wheeled. (Don't laugh, I'm serious)

Why is ebike spoke wheel hub motor so widely used?

Because of the two-wheeled layout of an e-bike, there is no speed difference between two wheels side by side like in a car. And the shock suspension of an e-bike is placed outside the hub, just like the shock hydraulic spring on the rear wheel, and there is no space limitation. Therefore, the e-bike can have the whole hub motor wrapped and sealed. This gives good dust and water resistance and improves the life of the hub motor. The use of hub motors greatly reduces the body structure of electric bicycles, making them lighter and smaller, reducing their weight and increasing their range, all of which have led to explosive growth and a huge market for electric bicycles.

But cars don't have these advantages. Cars have a front 2 and rear 2-wheel side-by-side layout. Such a structure does not have much effect when going straight, but when turning, the speed of the two symmetrical wheels on the left and right will be different, and to solve the speed difference, another set of differential equipment has to be added, which increases the volume and gravity of the wheel motor, making the compactness of the wheel motor less advantageous.

At the same time, the car wheel hub also has to be placed inside the suspension system, the space left is not generous, if you want to place the wheel motor, it will only increase the weight of the suspension, which is almost disastrous for the vehicle handling. You know that many cars now use aluminum castings to make suspension parts instead of steel, in order to reduce the weight of the suspension system by a few kilograms to improve the suspension response speed. But to join the wheel motor, with the current technology, the wheel motor does not achieve the ideal weight, which is also a problem that has to face the impact on the car suspension.

Why is ebike spoke wheel hub motor so widely used?

Moreover, because of the existence of the car suspension system, there is still a steering system in the front wheel, so there is no way to make the car wheel hub sealed in one piece like the electric bicycle wheel motor, so the dustproof and waterproof effect of the motor should be greatly reduced, which affects the life of the motor.

At the same time, because the speed of the car is much faster than the electric bicycle, it needs a more powerful motor to drive. In the relatively small space in the hub, the heat dissipation of the motor is also a big problem. Poor heat dissipation will also seriously affect the service life of the ebike spoke wheel hub motor.

Combined with the above reasons, ebike spoke wheel hub motors are not used much in the automotive field. The limited use of the field is also in the electric bus, because the bus size is huge, the arrangement of hub motor is relatively much more relaxed. But with the country's emphasis on new energy vehicles and the development of hub motor technology, I believe that in the future hub motors will definitely be used in large numbers on small passenger cars.