I picked up 3 of these from Aliexpress and they set a new China-My mailbox record of 1 week flat! Checking them out I'm impressed at a few of the novel details and A) Wanted to share this discovery as a micro(especially weird) motor enthusiast, and B) Ask a few questions about it in the case that anyone's else got them as well!
So, these are coreless motors attached to a high precision 4 stage micro-planetary gearbox. The output gear is laser welded to that threaded pulley which will turn the whole thing into a precision linear actuator when you add the plastic threaded cover. The cover also includes a contact that seems intended to act as a limit switch to index the encoder on when fully retracted. There is an integrated encoding circuit on the back and sensors on a tiny magnetic flywheel attached to a small diameter ceramic axle out the back of the motor. I think they used this mainly so that they can run it through the commutator contacts without shorting it. Seems to have gold plated brushes, and will run fine in both directions if you just wire directly to the motor contacts instead of using the flexible pcb cable. Despite the 4 stages of reduction its possible to backdrive this due to the high quality gearing. It delivers unexpectedly high torque for its size and is nearly silent. The threaded pulley is laser (or spot) welded to the output shaft, so I'm not sure if a press fit thru the gearbox is a good idea, but fortunately the pulley is steel and slightly larger than the motor/gearbox so you can put it in a vise and pretty readily knock it out with a small punch or hard nail. Pressing something else on with significant force might be detrimental, as they probably chose a weld for a reason- but you could probably use the same vise technique to press onto the the steel hub protrusion so long as you don't need something especially tiny.
That's about all I've investigated so far. In any case these seem like an unbeatable deal for $3.50/ea so hopefully we'll see more of them in use soon. Somebody has a massive supply of surplus here from the look of it.
Questions:
I haven't yet sorted out the 8 pin ribbon cable yet. There is an additional 2 contacts for the home index contact- I presume one to be 3v or ground. I'd like to use these with and arduino or similar microcontroller and would like any advice as to a recommend library or other references for something similar. Thanks for any advice there! I'm not even sure what to make with them yet, but excited to have a neat option like this.
*BTW- there is that pin list in the photos, but its a mixture of Chinese & some english, if anyone can translate that would also be helpful!
