Electronic – Small motor (P<10W) with high torque

gearmotor

I need to find a small motor (max 10W) with a high torque(max 1Nm) and low rpm(max 60rpm).

This question has been asked several time but I still have some doubts.

  1. I understand that the best option is to use a gearbox.

  2. The reason why find this motors is quite hard is explained in this
    question:

    You can play with all three of these variables, but there are definite
    limits on how much field intensity you can get with reasonable
    materials. Therefore, you end up needing either a long motor or a
    large-diameter motor, both of which require lots of extra (expensive)
    material to produce.

My questions refers to same applications in particular gimbal and robots. In this products is there a gearbox?

In particular the gimbal, I can't figure out how the manufacturer can put a gearbox in such small object considering also the axial and radial loads apply directly on the gears. I find also that there is a particular kind of motor called gimbal motor that should provide high torque and low rpm. Is there another type of motor or is it equal to normal BLDC motors?

The same problem is related to the robot. What kind of gearboxes do they use (if they use)?

Best Answer

The commercial gimbals work like this:

They have no gearbox, they're a BLDC motor in direct drive. The motors work the same way as a regular BLDC, but they have ultra low kv. The motors are driven open loop, similar to a stepper motor, since they're spinning too slow for the back-emf method that is normally used. And here's the important part: they don't actually have much torque! They depend on the load being well balanced to reduce the torque requirement.

Edit: Deleted some math, as it was incorrect.

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