pic: Its twins - prototype drives

[asid61]

Originally Posted by Max Boord

What are they geared to? low power use isnt just gearing. its efficiency and right angle gears are less efficient than spur gears like those found in conventional drivetrains. Size also has no meaningful effect on mechanical efficiency. Also are you saying overcharging the battery is a solution to pour mechanical design? i think what people are point out is that your drivetrain will push less hard, accelerate slower and reach a lower top speed as a result of the bevel gear stage.



.375 inch wheel drop is very aggressive even for a game like this years. .125 to .188 is pretty much standard.


So are you guys planning on running 6 inch wheels 4WD or some other configuration? 4WD is generally a bad idea in FRC and is inferior to a 6 or 8 wheel drive with 4 inch wheels for numerous reasons.

What exactly are you guys trying to get out of this drivetrain that could not be done with a standard 4 or 6 cim versa drive or even a kitbot? This is a 50lb drivetrain while people have made 25-35lb drivetrains out of 2x1 tube for years now. They are simpler, cheaper, have less custom parts, are stronger, easier to assemble and maintain, have more reliability can push harder, accelerate quicker, and weigh 20-50% less than this. the only advantage I see in this is that it gets the Cims out of the way and frees up some bellypan space. if thats your sole goal then i highly recomend checking out designs for gearboxes that put the cims over the top of the drive wheels. its a simpler and more proven concept than this and has many more upsides with none of the downsides i listed in this post.

Bevel gears are quite efficient. I'm sure that the OP is getting at least 90% efficiency out of them, unless the tolerances are way out of whack.
We used 3/8" drop due to the AM pneumatic wheels, and found that was a good number for us.For an 8WD, having a bit of extra drop doesn't hurt a lot as long as your CoG is near the center.
4WD is definitely not a good idea, agreed.
This drivetrain seems to save a ton of space compared to "normal" WCD setups, and doesn't take too many extra custom parts. They weigh less, but with a slight redesign this drivetrain too could be pretty light (maybe 40lbs for the whole deal). For this year, a 40-50lb drivetrain isn't usually a big problem because of the lightweight robots people ran in general, although the rest of the robot could be as overbuilt as this and cause you to hit 120lbs. Flipped CIM gearboxes don't save nearly as much space as this design.