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Designing drive belt and cogs with defined cog position....

Question asked by Dave Bear on Aug 31, 2016
Latest reply on Aug 31, 2016 by Dave Bear

Hi all,

I suppose this one is for those with great engineering or mathematical skills.

I need to design a matching pair of cogs that will be driven by a rubber belt.

The cogs are separated by a defined dimension that cannot be changed. The cogs also need to be able to maintain an exact 180 degree of opposite positioning as they are for opposing camshafts. So, basically when the keyway of one cog is true north so to speak, the other must be true south.

The maximum outside diameter of the cog (teeth) can only be 25mm.

A third cog of equal design could be added as a tensioner if trigonometry makes this design any easier. If not, I was just going to design a basic adjustable tensioner pad later.

I'm thinking perhaps the drive belt itself would have a 2 - 3mm back for the teeth to form off of also?


I have mucked around with this for two days now and cannot get all of these things to line up. If anything, the outer diameter of the cogs could change by 1 or 2mm max to solve the issue but it didn't help me. Attached is a rough draft, obviously each item would need to be created as a separate part. Any help, wisdom, links, tips, pdf or whatever is extremely welcome.


Kind regards,