Sprocket and Chain Assembly

james_lee020

Hello everybody, 

First-time poster here. I've been using Onshape for a little while now; ever since the beginning of the school year for my high school engineering class. As of now, I've started using Onshape for an entirely different purpose-- a robotics project for a high school club. It involves Tetrix MAX parts. As part of generating concepts, I have to develop a 3D model of my robot. The concept I'm very loosely basing it off of is posted below.

I assembled the chassis with relative ease. I also expect the armature system to be relatively easy as well. The only part I am struggling with is my drive train, which, as you can see in the reference image, uses a sprocket and chain system. 

I've also posted a screenshot of my Onshape assembly to show how far along I have come so far. I have the sprockets aligned and in place, but I don't know how to attach the chain to the sprockets. You can see in my reference image the way in which I want to weave the chain around the sprockets.

Could someone help explain to me how I am supposed to do this (preferably as simply as possible considering my level of experience)?

Thanks.
.

dirk_van_der_vaart

Just extrude the shape of the chain and pretend it's a chain

Alex_Kempen

Chain is tricky to do, and it can sap your performance quite a bit, especially if you're on a low end computer. One option to create chain is to create a sketched path of your chain in a part studio, then pattern sweep a link along it and create a composite part of the chain run. If you are on a low end machine, then I would recommend simply extruding the chain run as a block instead, like @dirk_van_der_vaart suggested.

There might also be a few chain FeatureScripts in existence which could help with what you're trying to do, but most only support single runs between two sprockets, so you're probably out of luck there.

imants_smidchens

sorry it took so long for me to see this: I developed a chain generator FS that might be exactly what you're looking for! You input sprocket positions as sketch points, sprocket teeth at each point, and the chain pitch, and it'll generate a (relatively) accurate model of the chain, telling you how many links it uses, etc. The spacing is as close to accurate as reasonably possible (equal spacing with linear interpolation between points, as opposed to the curve pattern) and has a reasonable library of standard chain models built in (or you can use a custom link)

https://cad.onshape.com/documents/1be886df2e36b431c92b2d61/w/791200d47653055fd5d51eb7/e/dbfe2637c98be2d89db5d08e