Belt Transmission

[Andoni C]

Hi there, we are planning a toothed-belt final drive. 1:3.6 reduction with 80kw peak power electric motor (217Nm; 3360rpm top values). A belt company has done some calculations. They gave us, 88mm diameter pinion and 285mm diam sprocket pulleys. (3kg and 12kg weight). This is unacceptable for any team. So where can I find a good belt without 15kg weight pulleys?

[Jon Burford]

try continental. we got a belt setup off them in 2011, which saved weight over a chain.

http://www.crpindustrialtiming.com/synchrochain.html

[Tilman]

There has been a speech at one of the FSG conferences some years ago about a belt transmission which used selfmade pulleys because everything that was commercially available was just too large. The number of teeth was around 11, I think. They machined it using EDM.

The slides are available here:
https://www.formulastudent.de/...shop_BEG_Abstatt.pdf

Edit: Please be aware that the team which built the car in the slides above went away from the belt solution the next year because the belts did not last long ... the problem was that the belt was bent in both directions and this destroyed the carbon fibres inside it quite fast. If you do not use a belt tensioner but make your differential position adjustable in order to tighten the belt it should last long enough ...

[Francis Gagné]

Projet VUE (Torque vectoring electric Smart) at our school used Gates belts with reworked pulleys.

https://www.facebook.com/projetvue

The setup is pretty nice.

[Mbirt]

I've had a very pleasant experience using Gates Design Flex Pro, which you can get for free here: http://www.gates.com/designfle....cfm?location_id=809

If you're looking for the lightest setup possible, consider the Poly Chain GT Carbon belt--it should be the strongest per unit width. Check out which sprocket size iterations are suggested by the program for your inputs.

Also, the pulley designs suggested to you by the belt company were probably industrial-grade pieces which could benefit from some analysis and rework for lightening by your team.

[Warpspeed]

The pulleys are very heavy because they are solid steel lumps.
With a bit of creative lightening, you can quite easily turn this:



Into something like this: