First Time setup for Lynxmotion Tracks

Lynxmotion Rovers, Sumo, and Tracked
1

This is my first time using tracks for a robot, and I’m not quite sure what all I need. I’ve settles on a design that has two tracks and uses 9 link sprockets.
Here’s a list of what I know I need:

2 - 2"x23" MTS Track
4 - pairs of 9 link sprockets
2 - universal 4 mm or 6mm hub (haven’t decided on motor yet, so size unknown. Also only two sprockets will be driven, so I think I only need two, is that right?)

After that I’m not quite sure. Do I need the passive idler hubs? Do they just hold pairs of sprockets together? If I need them, do I need 2 or 4 pairs? (They’re sold in pairs, do I need 1 per pair of sprockets, or 1 pair of passive idler hubs per pair of sprockets?)

Is there anything else I need that I don’t know about?

Thanks for the advice!

2

Can you provide a drawing or visualization (ideally with dimensions) of one side of the track you want to make? The more details you include, the better we can help.

3

[Album] Imgur

[Album] Imgur

This is just a very rough sketch of our setup.

EDIT: The image uploading doesn’t seem to be working, do you have any tips for that?

4

Can you upload them as attachments? When you click reply, there is a field below the window which is by default closed called “Attachments”.

5

there we go! thanks!

robot tracks 2.jpg
robot tracks 2.jpg2448×3264 512 KB

justtracks.jpg
justtracks.jpg2261×1473 504 KB

6

Note that if the height is 6", the overall length of the track cannot be 6" as well.
Careful about making the tracks long but not wide.
You would choose either one or two sprockets as idlers, and one sprocket as driven (per side)
lynxmotion.com/p-1115-mts-18 … o-hub.aspx

7

Got it thanks! So the passive idler hubs are just for whichever sprockets aren’t driven.

I’ve got one last question though. Do you guys have any data about the coefficient of friction of the rubber with any other surface? I know the hardness is Shore A 45, and I can compare that with other products, but our motor guys wants friction data so he can pick a motor knowing we won’t slip at stall torque.

8

We have not really tested the idler hub with the larger sprockets - they were intended to be used with the 6T and 9T sprockets.
Unfortunately we don’t have any data regarding friction for the tracks. It will depend on the contact area, the weight on the tracks, the angle, and the surface it’s on.
You’ll also need to estimate the total area of contact since the tread is not filled in (there’s a pattern).

9

I was only planning on using the 9T sprockets, I think my drawing was just really poor. So to make this work do I need to buy 4 pairs of sprockets or just two pairs?

10

The 9 tooth sprockets are not 6 inches. If you use the 9-tooth, you can use the idler. You would need four pairs (since you need a pair back to back at each position - they are not meant to work as “single”).