Are Geared motors Brushless DC?

[ross]

Hi all,

I'm currently a senior selective high school student studying engineering studies as one of my subjects and I've be selected to do an open design and research project on designing a new propulsion system on bicycles with the criteria of the motor being light, safe (be within the capability of the existing braking system) , durable(lasting more than 5 years), efficient, must be able to attach and detach with ease, no changes of the current braking system of an ordinary bike and cheap.

Thus, I'm balancing out between geared and gearless hub motors as whilst leaning more towards geared hub motors for its light weight option + efficiency yet I'm quite torn for disregarding gearless hub motors as they are quite durable and is relatively cheaper but it is a lot heavier.

Whilst researching on these topics I've come the the conclusion of most likely choosing the design of a front geared Brushless DC hub Motor.

However, I'm thoroughly confused at some sites suggesting that all hub motors are DC Brushless, which I can see being applied In the gearless Hub motor, but what about the geared hub motor? As it operated on planetary gears how is it classified by any chance as a DC brushless motor?

Also, in terms of a geared hub motor how durable would it be if one replaces the plastic teeth with steel teeth? Would it last more than 5 years without maintenance or would that be stretching it?

Thank you all so much for reading this and I urgently look forward to your Replies!

Kind regards,

Ross

[spinningmagnets]

Yes, they are brushless DC. Here's an article that might help with some of the basics

https://www.electricbike.com/motor-tech-learn-the-terms-part-1/

[ross]

thanks very much

[Tatara]

Hi,
Curious about your design project flow.
Any pros and cons of e-bike geared and gearless hub motors? I'm doing my school research and need to write my paper comparing those. Perhaps some users here could share their experience.
So I thought I might take a Stromer or BionX gearless hub for a review.

[spinningmagnets]

Tatara, geared hubmotors need to be carefully used within their designed performance envelope. they have a poor heat-shedding path, and can overheat if abused. However, the gears multiply wheel-torque so they are often used to provide a reasonably powerful motor in a small and light package. Best used on relatively flat land or mild hills.

Recently there have been more models added that are larger than previously. The MAC is the most common large geared motor, and is the benchmark others are compared to. It remains to be seen how the new larger models will do. The gears are typically plastic to form a cheap "mechanical fuse" so if the motor is used in a way that exceeds it's limits, the part that breaks is fairly cheap and easy to replace.

Direct drive hubmotors are typically larger in diameter, which can make them relatively heavy. They are capable of high power peaks if the max amps are applied for a short while. If 10ml of ferro fluid is added, it forms a thermal bridge between the hot stator and the spinning aluminum sideplates. This allows the motor to more readily shed any internal heat, and it dramatically prolongs the amount of time that the rider can apply max amps for brisk acceleration without damage to the motor. A direct drive hubmotor with a sine-wave controller is incredibly silent.

[K442]

...

However, I'm thoroughly confused at some sites suggesting that all hub motors are DC Brushless, which I can see being applied In the gearless Hub motor, but what about the geared hub motor? As it operated on planetary gears how is it classified by any chance as a DC brushless motor?
...

Welcome to the wonderful world of engineering choices and tradeoffs! On your original question, geared/non-geared and brushed/brushless are two completely independent motor properties. The gear/non describes how mechanical work is transmitted out of the motor and the brush/brushless describes how electric power is used /transferred inside the motor. With that said, most any modern motor over any trivially small power or efficiency rating would be brushless, regardless of it being geared or non-geared.