A couple moths ago I was standing on my longboard while talking with John, and glanced down at the trucks and said to him “I wonder if I could put a motor on this”. Discussion ensued for a few minutes afterwards. Within a couple weeks, I started designing something that could clamp to the truck and offer support to a motor mount plate. The first test cut looked like the first picture below. I don’t have any good renderings of the “completed” version 0.1 but the but long story short; the flexing c-clamp nature of the design made this bad. It was later switched to a two-part clamp.
Interestingly enough, within a couple days of my first designs, I met another ProVolt member, Mike, that already had the electric motor, speed controller, and remote to actually build this thing! So we put together a quick improvised single-piece clamp that actually worked quite well for a while. I’m not sure that this dimensions used in this next rendering are correct, but you should get the idea. It had some limitations.. we couldn’t use very thick metal, or else the motor shaft was completely covered. But it worked for at least a few miles worth of riding, even if it was vice-grip’d on for the first test ride.
So I played around with the design some more and cut this next one one! We put quit a few miles on this mount, eventually the outer clamp cracked through one of the thread holes and was showing some pretty extreme signs of abuse. It would need beefed up and also modified to not rely on friction fits anymore.
So we gave it TEETH so it could BITE!
RAWR! Each tooth adjustment gives 10 degrees or rotation. In practice, this seems to be the right amount. The first one had a circular insert before we had square trucks to clamp to.
The assembly is driven based off of the pulleys’ teeth count and the belt size. All I have to do is export and cut it. I’ve relied heavily on solidwork’s ‘configurations’ in this design. The three-piece motor mount shown above was modeled as a single multibody part, and each configuration mated to itself the the assemble level. Leaning new things is fun! This has certainly been an iterative process.
And here’s the most recent version that’s up and running! It goes up to 24 MPH, and will happily run 8 miles from two new 5000mAh 4s lipo airplane batteries (10Ah, 33.6v). The batteries we’ve been testing with are pretty worn ad barely last half the distance. The next step is to build some beefier battery packs out of 40 LG HG2 18650 cells in a 10s4p configuration. That’ll be a 120 Ah 42v pack, I’m very curious what kind of range we’ll see.