Gear motors - quiet?

Hi there,

i'm building a project using 4 gear motors. First I've got the same geared motors from Wattrott but they proved to be too noisy while turning. So i put them into a semi-isolated wooden box (w/ cotton wool). Now I've got new motors 60rpm and 30 rpm. They are both gear motors and have a bigger cylinder at the frontend (it's the gear box) but they are still noisy, while turning. Is there any way that i can isolate this noise? The project is suppose to be quiet but the noise is destroying the piece. How can I quiet the motors?

any ideas?

ummmm... lubricate them? pour some machine oil down the shaft... ;)

Are you driving them with Arduino PWM? If you are, the default low-frequency PWM can cause noise in the audible range. For the quietest operation, run them at 20kHz or more so that the PWM and any vibration caused by it are out of the range of human hearing. Besides that, you will get some gear noise, brush noise, and wind noise from the motors anyway.

dze: Hi there,

i'm building a project using 4 gear motors. First I've got the same geared motors from Wattrott but they proved to be too noisy while turning. So i put them into a semi-isolated wooden box (w/ cotton wool). Now I've got new motors 60rpm and 30 rpm. They are both gear motors and have a bigger cylinder at the frontend (it's the gear box) but they are still noisy, while turning. Is there any way that i can isolate this noise? The project is suppose to be quiet but the noise is destroying the piece. How can I quiet the motors?

any ideas?

Most such motors use spur gears, which are quite noisy. If you need a quieter gear train, look for motors with helix (or better - double helix) gears (in addition to gears made from a plastic, like nylon or delrin); note that such gearheads/motors won't be cheap...

could you re-engineer the design to use a belt/pulley system?

note that such gearheads/motors won't be cheap...

AKA, "good, fast, cheap..., chose any two!" :)

thanks guys for advice.

Antzy; no i can't it's in a metal casing

BetterSense; I'm using adafruit motorshield to run the motors and i'm changing the speed in the code. so yes i'm using pwm. ok i'll try it out with 20kHz.

cr0sh; hmm, helix and double helix gears? any good links in europe?

scott_fx; i've not really tried with belt and pulley system yet. i really don't know where i can find such stuff. might be interesting to get hold of some to try.

dze: scott_fx; i've not really tried with belt and pulley system yet. i really don't know where i can find such stuff. might be interesting to get hold of some to try.

im sure there are a ton of other options but here is one: http://www.robotshop.com/search/search.aspx?locale=en_us&keywords=timing%20pulley

The way to isolate the noise is to mount the motor to the chassis via rubber mountings - then the high frequency noise isn't passed to the chassis, you can put acoustic wadding around the motor/gearbox too, but be aware of the need to cool them. The actual spindle from the motor will pass some vibration but it won't be so much I think. Flexible couplings can help here.