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Belt drives?
Posted: Sun Mar 20, 2011 2:52 pm
by DanL
Started thinking ofusing a belt drive instead of noisy, expensive gearbox.
I got my hands on a tachometer and measured motor speed and drive wheel RPM. Motor speed was fixed and averaged about 2000RPM (varied about 1900 -2100) and drive wheel was 20.5 RPM. Total gear reduction then is about 98:1.
The gearbox is a Tamiya with a Schumo "geardown" unit on it. Standard Tamiya motor.
To get about 100:1 is easy with standard miniature drive belt parts. Only three reductions are needed. A LOT of advantages over gears I think for R/C tanks.
Sketch of a 107:1 belt drive attached. Slightly smaller than a Tamiya gearbox.
This looks like it will work.....maybe time to start scavenging for belt drive parts....
Re: Belt drives?
Posted: Sun Mar 20, 2011 4:10 pm
by wibblywobbly
Amazing...this though was going through my head too a couple of days ago?? There are many advantages to using belts, especially toothed ones, over the metal gearboxes. It would make it easier to install boxes in small 1/16 models like Bren Gun carriers and Hanomags etc.
Re: Belt drives?
Posted: Sun Mar 20, 2011 7:32 pm
by tankmad
Sounds good but you would need belt tentioners and where do you get the belts and pullys.
Stevie
Re: Belt drives?
Posted: Sun Mar 20, 2011 7:37 pm
by wibblywobbly
There are suppliers for this type of thing, I have seen them about. Other RC modellers use them, especially on boats where they want to automate moving guns etc. It would be interesting to see someone build a pair of gearboxes that work?
Re: Belt drives?
Posted: Sun Mar 20, 2011 8:03 pm
by Saxondog
VCR Belt driven components may be the supply side option,the frame is an issue and the bearings the pulleys turn on,plus the shafts.
I have no doubt this is a better system, that's why bikes are belt driven,less torque needed,less weight less horsepower wasted turning heavy sprockets and chains.
So Dan when do we start? Because possibly the gearbox shafts and frame could be converted to belt drive saving alot of work?
Sax
Re: Belt drives?
Posted: Mon Mar 21, 2011 12:14 am
by blimp
I've been thinking along those lines as well , but vcr belts are either flat , square or round . what we need is something like these -
http://www.motionco.co.uk/pulleys-belts ... 25_38.html" onclick="window.open(this.href);return false;
Re: Belt drives?
Posted: Mon Mar 21, 2011 10:16 am
by Dietrich
Hi Blimp, :~
Sorry to cut in.....

.... but just to make it clear the company whose link you posted also do the
gear wheels as well and they also are intended for use with
their Drive Belts in
Models....
http://www.motionco.co.uk/timing-pulley ... 35_48.html" onclick="window.open(this.href);return false;
Sorry again Blimp and a good spot on the company,
Alb.
Re: Belt drives?
Posted: Tue Mar 22, 2011 6:28 pm
by 971wright
Hi Your going to have problems with the drive shaft end(cant fit a 10t pully if you make it 3mm it will not be strong enough).The dia of all Tamiya and heng long drive shafts is 8mm dia,so to fit a pully to this dia you would have to fit a plo32al which is almost 21mm outside dia(this may also mean fitting a bulge to front glace and might not let the upper hull fit).So acording to your drawing it will not work you would have to move the motor back and fit an extra gear down,motor with a small pully to large pully, small pully to large pully finaly small pully to the final pully.
Might be a good idea in but in practice I dont think its going to work.
regards pete
Re: Belt drives?
Posted: Tue Mar 22, 2011 7:22 pm
by Frayed Dave
If you're looking for pulley belts,have a look at the final drive on a Tamiya TLT rock crawler,it uses a belt and pulley system.
Dave
Re: Belt drives?
Posted: Wed Mar 23, 2011 2:23 pm
by DanL
971 wright,
I'm working with a sales engineer at SDP-SI. The drive shaft pulley will be 18 groove, full diameter = 16mm.
Polycarbonate/glass filled. I measure 9mm shaft center to frony hull wall on a Tamiya KT, which should allow clearance of an 8mm radius pulley.
Pulley on final shaft will be bored out to fit and will likely need to be fixed with an adhesive. Will be essentially a "jacket" of teeth on the shaft.
"I'm often wrong, but never unsure!"