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# Chain center distance

#### tomh

##### New member
If I had the chain drive pitch dia., the idler pitch dia., chain pitch and a general idea of the center to center distance how can I get Pro to give mewhat the actualcenter to center value?

draw it dude. it helps

i dont see why u can not simply dimension it.

well dude,My goal is to have a spline that you entry the drive pitch dia., idler pitch dia., chain pitch, and a rough length ( as close as possible). Then the model will run throught the relations and parameters giving me the exact center to center distance for the chain pitch. With this I will be able to create a flexibleassembly or a family table for any chain length and chain pitch. This way the process will be more automated saving me time.

So the answer to the problem has to be awhole numberthatis divisibleby the chain pitch.I do not have the ability to edit pro/program because I do not have Pro/Assembly, hence the need to use relations and parameters.

I assume you have the formular for the theoretical center distance. Couldn't you just use a MOD function or something in a relation to force it to an integer chain length? I'm just thinking out loud - I might not understand what you're up to.

Dude.... Like, Pro-E Foundation is so... lame... I feel your pain.

Edited by: scottm

easly fixed.

u could do something like

View attachment 684

here u can have ur values fixed to parameter values

then highlight the entire loop, and goto

edit->convert->perimeter then select the center to center distance.

now changing the center "chain length" will change the center to center distance.

i think there is some equations that u need to follow in reality since
chains dont really go around a circle but rather do it in small cord
lengths. check ur catalogs. inface post the equation as i would like
to know it .

Hope this helps Doode

Look in the Machinery Handbook and you'll find the formula for calculating the center to center distance.

I struggled with the same issue for quite a while. The answer was a MathCAD calculation sheet that took care of it, then based on that and a lot of patience I created the chain assembly.

Good luck, and if you find a simple way of doing this tell me, I'm curious.

i dont have that book Ibotez. if u give me the formula i will work something out for u guys

One more thing that one should take care when modeling chain: prestress. All chian drives are assembled with a prestress to ensure the chain runs tight at all times.