|
Sawhit and Capt make a good good point. Standard gear stock would work but you would need a quite detail oriented machine. But also we would need to have the drawings perfect in order to get it to work. It's great to have the ideas, and I think everyone here has great ideas, but we need to work on some specifics. Either today or tomorrow I'm going to start taking some measurments of the rear end of the chassis where the tranny would be.
Also, I've been tring to think of the material to use for the contact area for the second gear. I'm not sure if was mentioned here but someone had said to use sandpaper. I don't think this would work because a) it would wear down the inside of the gear, and b) the sandpaper would wear out pretty quickly. I think since the weight and materials we are dealing with are fairly small scale that some kind of rubber would work best. Maybe even some of the material from the XMods tires. This way it wouldn't wear down the inside of the gear but would be easy to replace when the rubber itself does wear down.
I think all of the ideas are really starting to make sense! Everybody seems to have really good ideas and people seem to be seriously thinking about this. I am willing to spend some money to make this work, but we need to solidify our ideas first. So, let's sum up what we have so far:
The basic principles is to use a centrifigul transmission. Any other kind of system would be too big and too heavy. So, the way this would work is there is a standard first gear the spins on a one way bearing. This means that when the motor is spinning the first gear the bearing acts like any other bearing, but once the clutch shoes engage the bearing it basically just works as a free floating assembly. The second gear is larger so the same amount of rpms=more wheel rotation. So while in first gear, the rpms rise and the clutch shoes move out until they press against the inside of the second gear. Once the second gear engages, the first gear just rotates freely without having an effect on the actual wheel rotation.
Now, as I was writing this out I've come up with a few issues. The motors we use for the XMods rev up to max rpm almost instantly. So the first gear wouldn't be engaged very long. I'm not sure if this would actually be an issue, because the short amount of time that the first gear is engaged would probably be enough to get it up to a great enought speed that when the second gear engages it would basically just take over for the first gear and continue rasing the speed.
Also, before we send this out to any machine shop we need to determine exact gear sizes to make sure that we are getting the most out of the system.
Later on today I will be breaking out my old engineering books and trying to figure out some gear sizes. Also I will try to get some measurments on the rear end of the chassis and start to mock up a non rotating assembly.
Anyways, we seem to have the right group of people working on this so let's get cracking and see what we can do. I definitely think we're making some progress. I should be back later on today or first thing tomorrow with some of the calulations i've come up with.
Take it easy everyone.
Peace
Jeremy
|