pic: Team 192's 2013 Gearbox

[Joey Milia]

Originally Posted by Andrew Lawrence

Just curious - why the tiny output shaft? That looks like it could barely hold a sprocket.

One of the goals of the gearbox was to reduce it's footprint, and that includes the space it takes to install and remove it. To that extent the output shaft is split into two parts, half in the gearbox, other half in the sprocket and wheel. This allows the gearbox to be removed after pulling it only 5/8 of in inch into the robot, instead of the 2-3 inches that would be required otherwise.

More specs,
two speed shifting 17fps and 6fps
Cim to cluster shaft is 3mm GT2 Belt

and yes, there is a bevel gear in there.

[DampRobot]

Just wondering, do you have any idea about the gearbox's efficiency? Just looking at all those shafts makes me wonder if you're loosing some power through all those reductions.

But seriously, that looks like a marvel of smart design and good machining. So many bends and bearing holes, all lining up perfectly...

[Joey Milia]

Originally Posted by DampRobot

Just wondering, do you have any idea about the gearbox's efficiency? Just looking at all those shafts makes me wonder if you're loosing some power through all those reductions.

I don't have any hard data on efficiency but it's just a three stage shifting gearbox, one of which is belts from the cims. All stages are in the 98%-99% range, add on the sealed bearings and I would expect an efficiency in the low 90s.

[sdcantrell56]

Originally Posted by Joey Milia

I don't have any hard data on efficiency but it's just a three stage shifting gearbox, one of which is belts from the cims. All stages are in the 98%-99% range, add on the sealed bearings and I would expect an efficiency in the low 90s.

How are you getting such high efficiency per stage?

[Joey Milia]

The main reductions are spur and bevel gears, which, when alined properly with accurate tooth profiles and proper lubrication are extremely efficient. Once again I have no measured data to support these estimates, they are based on subjective observations and engineering manuals (mostly engineering manuals).