Timing Belt

ede_N_

I'm trying to make a timing belt for my engine block and I have no idea how to start off, Does anyone have suggestions on how to create such a thing; something to align with all the teeth and make it spin / rotate with other gears and other teeth?

Thanks! 

Link:

 https://cad.onshape.com/documents/a7db7002771dafcfc6ee1e89/w/438796e7a338ae7de57d6502/e/4cf21d2e2d4f6615598a04e6?renderMode=0&uiState=64e285cd0487c867774b6c57

eric_pesty

Here's a quick example showing how I would figure out the location of the teeth of each pulley and how to build a simple assembly. You would still need to add an "idler" in there to get the total belt length to be an even number of teeth (and a commercially available one too...) but the process would be the same.

https://cad.onshape.com/documents/611c3ab26a69f5d5bdb27f57/w/df7d43f0f9ca03812a1467a3/e/3154b6231086cff8c857332f

robert_scott_jr_

Check out the link below. Perhaps it'll help. - Scotty

https://www.onshape.com/en/resource-center/tech-tips/how-custom-features-make-belt-routing-easy

eric_pesty

Use "gear relations" in the assembly to make the different pulleys rotate.
The physical "belt" part is only going to be "visual".

As far as aligning things in your design, I am not aware of a tool that will do this for you. You will have to figure out the angle of the pulleys relative to your shafts "manually" to match the tooth spacing.
I would start with a sketch showing the locations and "pitch diameter" for each pulley, pick the first tooth on your main pulley and then create an arc-line-arc that ends at and adjustable angle on the next pulley and adjust until that length is a multiple of teeth spacing. Then repeat for each pulley.

A good tip is to use "measure" variables after your sketch and enable the "final" button when editing your sketch to see the effect in real time.

eric_pesty

Here's a quick example showing how I would figure out the location of the teeth of each pulley and how to build a simple assembly. You would still need to add an "idler" in there to get the total belt length to be an even number of teeth (and a commercially available one too...) but the process would be the same.

https://cad.onshape.com/documents/611c3ab26a69f5d5bdb27f57/w/df7d43f0f9ca03812a1467a3/e/3154b6231086cff8c857332f

billy2

Probably the most important thing in my opinion is that the sketch above is representing the pitchline for both the pulleys & belt. 

I'd add a large diameter representing the outer pulley diameter and then offset the belt path to represent the belt thickness.

In another sketch, I'd detail out the teeth. I wouldn't combine them in one sketch (belt/pulley layout & tooth details).

If I'm on the clock, I wouldn't ever show the teeth.

ede_N_

eric_pesty said:

Here's a quick example showing how I would figure out the location of the teeth of each pulley and how to build a simple assembly. You would still need to add an "idler" in there to get the total belt length to be an even number of teeth (and a commercially available one too...) but the process would be the same.

https://cad.onshape.com/documents/611c3ab26a69f5d5bdb27f57/w/df7d43f0f9ca03812a1467a3/e/3154b6231086cff8c857332f

Thank you so much Eric, I appreciate the help

ede_N_

robert_scott_jr_ said:

Check out the link below. Perhaps it'll help. - Scotty

https://www.onshape.com/en/resource-center/tech-tips/how-custom-features-make-belt-routing-easy

This helps but I was wondering how to make teeth on the belt?

ede_N_

eric_pesty said:

Here's a quick example showing how I would figure out the location of the teeth of each pulley and how to build a simple assembly. You would still need to add an "idler" in there to get the total belt length to be an even number of teeth (and a commercially available one too...) but the process would be the same.

https://cad.onshape.com/documents/611c3ab26a69f5d5bdb27f57/w/df7d43f0f9ca03812a1467a3/e/3154b6231086cff8c857332f

This is sweet, but complicated, I appreciate the help and its time for me to figure out how to do this without breaking my monitor. Thank you : )