High performance nema11 stepper motor

[Falon]

Hi everyone,
I am looking for high performance stepper motors for a project where I am trying to minimize the size of the device. Essentially, the Nema size of the stepper motor directly determines how flat I can design the device (the length of the motor is not important and the price is secondary). Now, the stepper should produce at least 0.27 Nm (= 38 oz-in) of holding torque and hold that torque well until about 400 rpm. The best I could find for these requirements was the Nema 14 stepper from oyostepper.com: https://www.oyostepper.com/goods-15-Nema-14-Stepper-Motor-Bipolar-18-deg-14Ncm-20ozin-04A-12V-35x35x26mm-4-Wires.html.
and I am looking to reduce the size even further beyond the 35 mm that this motor offers. Any suggestions on where I can find a small but powerful stepper (perhaps a Nema 11 with similar performance)? Or any ideas for other alternatives?

 

[MarkT]

Motor torque scales with rotor volume I'm afraid, unless you can find a long-stack NEMA11 you are limited by the laws of physics. For more torque a gear-motor is the usual approach, but that will decrease the rpm.

A servomotor (not hobby-servo, a servomotor) with gearbox might be a better approach, with 10:1 gearing you'd propably get the torque and speed you want, but the issue is the size of the encoder and controller, and finding something meeting your requirements.

BTW do you need absolute position control - if not a stepper would not be the right choice of course...