pic: 1881 new gearbox design

[GMAdan]

loading photo ...

[Jeff 801]

Is the gearbox a servo shift

[camtunkpa]

Nice compact design! Great to see a second year team looking to design gearboxes. Out of curiousity, how are you shifting? i.e. dog, mesh, ball, or an entirely new method?

[Greg Perkins]

Dual speed, Check
Servo Shift, Check
Compact Design, Check

VERY Very good work guys, and Very good CAD model.

[Tristan Lall]

Have you considered how you will attach the CIM motors to the gearbox plates? You don't seem to be using both of the #10-32 UNF mounting holes on the front plate. Be aware that the other two holes on the front plate contain long bolts that hold the motor case together, and therefore may only be marginally suitable for mounting.

Also, while the lightening pockets are a good idea, have you considered that there's almost no clearance between opposite edges of the pocket in the lower corners. Unless you're casting it (not likely), or milling it with a tiny end mill (why?), you're going to have an issue with actually creating that detail. Also, you seem to have several non-circular curves in your lightening pockets. This implies you're going to make it on a CNC mill—is that your intention? If not, use straight-sided pockets.

[Tytus Gerrish]

Counting the teeth. that gearbox has ratios of 2:1 and 3:1. with a CIM motor that gives you an approximate output speed of like 2500 rpm and 1500 rpm. that’s not getting much use for that gearbox's size and massively thick gears. and in an attempt to keep it small you removed the material of the plate that the motor needs to mount to. That is however some very impressive modeling with the pockets in the plates, the bearings and as far as I can tell from that render Nomenclatural correct Gears with some weight reduction. I remember myself modeling stuff like that back when just starting to use Cad and making it look super good. its just that i got so far into the aesthetic details of things that I skipped over doing the math in the bearing and meeting the requirements of my designs. Often a wheel speed to aim for is around 70RPM for a 6” wheel. In high gear, if you were to use that gearbox with a chain drive you would need a sprocket ratio of about 35:1 that may mean using a 12 tooth sprocket and a 420 tooth sprocket on your 6-inch wheel. seeing as how a 420T #35 sprocket would be around 50 inches in diameter. That won't work

[GMAdan]

Thanks for the comments/suggestion. It's a ball lock shifter. I have relized my gearing mistakes, sorry i'm kinda new at this and made some math errors its back on the drawing board( well this case sketch plane) for me thanks.

[Tytus Gerrish]

No need to apologize, you didn't do anything wrong. your just learning. thats what the forums are for. please keep them coming. just Don't start taking bad blury pictures of things and call them teasers