Motor / gearbox advice

Help & Support Robot Parts
1

Hi,

I’m building a model tank robot in 6th scale. I currently use 2 cordless drills which have a reduction gearbox to produce a stall torque of about 26Nm with a max rpm of 350RPM.

Specifically these are KATSU cordless 12v drills.

I’m not happy with the design since it fudges some design points and makes it a little unreliable.

So, as part of a redesign, I was looking to use a better motor gearbox combination.

How does the P61 gearbox and 550 motor compare?

My model weighs 16kg and is circa 800mm long, and has a tracked width of about 400mm.

Many thanks

3

Hello @RobbOnTheRock and welcome to the RobotShop community!

The P61 Gearbox comes in a variety of gear reduction options so it depends on which one you choose.

The torque and speed calculations when you have a gear reduction are very simple:

  • Speed’ = Speed / Gear ratio
  • Torque’ = Torque * Gear ratio

The only P61 gearbox I see available on the US site is the 256:1 one so I’m going to be referring to this one.

  • Speed’ = 19300 RPM / 256 ~= 75 RPM
  • Stall Torque = 69.16 oz-in * 256 ~= 17856 oz-in ~= 125 Nm
1 Like
4

Hi,

Thanks for the response.

I’m wondering if there is any established calculation spreadsheets for track laying robots to determine motor power requirements?

I have a spreadsheet which I’m happy to share assuming that it’s of use and any short comings can be be developed.

With regards to the motor, thanks, I’m looking to try and return a max of 26Nm stall torque ideally with a maxed 500 rpm.

Currently my model is running at 350RPM.

Keen to hear some thoughts.

Many thanks
Andy

5

Hi!

I’m wondering if there is any established calculation spreadsheets for track laying robots to determine motor power requirements?

You can try using this tool:

I have a spreadsheet which I’m happy to share assuming that it’s of use and any short comings can be be developed.

Yes, that would be great!

With regards to the motor, thanks, I’m looking to try and return a max of 26Nm stall torque ideally with a maxed 500 rpm.

Maybe this motor could work for you:

No-load speed : 490 RPM
Rated Torque: 3 kg.cm ~= 29 Nm