Friction Drive DIY - solar charged

I posted this some time ago. As I say, it's interesting because the guy says you can use it in the wet:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=9652&p=183987&hilit=capstan#p183987
 
paultrafalgar said:
I posted this some time ago. As I say, it's interesting because the guy says you can use it in the wet:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=9652&p=183987&hilit=capstan#p183987
Click to expand...

I do remember that post. Some of the guys other comments were interesting too like saying a knurled aluminum roller was too abrasive on the rear tire. I'm not sure what kind of aluminum he was using but I can tell you from experience that a 6061-t6 knurled roller will wear out well before a tire will. I had to re-knurl mine every few hundred miles. I'm now using a knurled hardened steel roller and my rear tire has several hundred miles without much wear at all. The roller still looks new too.

His comment about sending a skateboard wheel to a chemical lab made me chuckle a bit too but hey, maybe he did. I didn't think it was a secret that they were made from urethane.

I suppose it's possible to find a roller that would work in the rain. I just haven't pursued it.

BTW Solar Motion, nice setup. I don't think I ever got around to commenting on it before.

I noticed you talking about the roller walking off to the side. I found if you use a 'floating' roller like the one on the EV Warrior that you can stop most of that problem. I'm using an outrunner with quite a bit of power so I use struts from the rack to the rear dropouts but I went quite a few miles without them and the roller never moved off the tire. I do, however, think it's a safety issue with friction drive (especially with a lot of power). I would hate to be riding at 30 mph and have the mount slide over and hit the tire. Something to think about for sure.
 
This is an interesting roller potentially to use in this application:
http://www.goldmine-elec-products.com/prodinfo.asp?number=G15808
It's got one-way bearings in it, so it could freewheel when the motor isn't in use. They're only a buck right now.
1.18" (30mm) diameter x 1.66" (42mm) Long rubber roller features a nylon brushing which has an internal "one way direction of rotation" metal ball bearing. The roller is designed to slip onto 8mm shafts. It rolls freely in one direction, but stops in the reverse.
Click to expand...
 
Nice work, I'd like to have a friction drive such as that.

You could save a little money buy using a cheap scooter controller (they work fine, never any problems, and they are much smaller), and using the cheap Tamiya connectors that most scooters use. Those Anderson ones look like overkill. Those have been working fine for me too. TNC scooters has the best selection and prices.

But I love the mechanical part - great work.
 
Since I have a bunch of those motors lying around here, I have to do this build. No more noisy geared motor! And no interference with the pedals.

This is such an economical build, I think every DIY newbie should go this route.


The only hard part for me is going to be getting that roller on the motor shaft, which doesn't have a key slot.

Amberwolf - that roller is perfect, except that top speed will be only 15mph unless you overvolt those motors.

Wait....how about an RC outrunner... :lol:
 
veloman, SDP-SI makes $16 shaft flanges (actually listed as a shaft Flange mount, take caution to order the FAM rather than the BAM, "B" meaning Base-mount). This one is aluminum and has a split to allow clamping to the shaft, 10mm-25mm bores avail, split sleeving available to adapt to various inch and metric shafts.

https://sdp-si.com/eStore/Direct.asp?GroupID=367

SplitShaftFlange.jpg

You can also use one of the small shaft-sprockets you may have laying around (like a 9-tooth?). If you set two or three screws hrozontally through the valleys of the sprocket teeth into the selected roller, it might work. A grinder/Dremel can be used to cut a depression into a shaft, and a set-screw can hold it onto the shaft (if its the set-screw style).

SDP-SI also makes split-sleeves to reduce a 1/2" attachment-ID down to 12mm, 10mm, and 8mm for concentric clamping onto a smaller shaft.

143265tmb.jpg


47T_skilletSprocket.jpg
 
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