pic: ABS-101 Front

[Joe G.]

Originally Posted by JesseK

This looks really nice and compact, though I wonder how you plan to keep the output shaft attached? Or is that an inner race of a hex bearing?

192's gearbox, the setup that I believe inspired this one, used a hex sleeve as it's output shaft, and a separate hex shaft permanently mounted to the drivetrain for the center wheel. This allows the gearbox to be removed without removing any wheels.

[asid61]

Originally Posted by Joe G.

192's gearbox, the setup that I believe inspired this one, used a hex sleeve as it's output shaft, and a separate hex shaft permanently mounted to the drivetrain for the center wheel. This allows the gearbox to be removed without removing any wheels.

Correct on all counts. I updated the description.

[Rauhul Varma]

Nice job!

The biggest thing that stands out to me is the shield doesn't seem particularly useful, necessary nor easy to make. Having a large slot for the chain leaves a lot of room for material to be sucked into the gearbox and once debris in there, a shield can actually speed up the wear of the gears; this is why 192 makes their drivetrain almost 100% sealed (and maybe 100% this year). Additionally, if you look at 254 they do not use shields on their gearboxes and have (obviously) had a lot of success. I would consider reevaluating your use of one here.

(One last thought: machining holes in your plates to mount the shield will be more difficult than it was on 192's 2014 gearbox as your plates curve out)

Anyways good job, I'm curious to see how the 5mm GT2 belts do!

[asid61]

Originally Posted by Rauhul Varma

Nice job!

The biggest thing that stands out to me is the shield doesn't seem particularly useful, necessary nor easy to make. Having a large slot for the chain leaves a lot of room for material to be sucked into the gearbox and once debris in there, a shield can actually speed up the wear of the gears; this is why 192 makes their drivetrain almost 100% sealed (and maybe 100% this year). Additionally, if you look at 254 they do not use shields on their gearboxes and have (obviously) had a lot of success. I would consider reevaluating your use of one here.

(One last thought: machining holes in your plates to mount the shield will be more difficult than it was on 192's 2014 gearbox as your plates curve out)

Anyways good job, I'm curious to see how the 5mm GT2 belts do!

I can remove the polycarb shield if needed, and because it's on the bottom of the gearbox I might do that (it's not a safety concern).
If we did use it, we would velcro it to the plates, so I didn't add mounting holes.
And if we ever make this gearbox, it will be in a few weeks to months at best. I'm one of two machinists, and the other one can't work for a while due to school. Mainly I put it up on CD to get opinions and release the CAD.
Thanks for the input!

[Dunngeon]

Originally Posted by asid61

I can remove the polycarb shield if needed, and because it's on the bottom of the gearbox I might do that (it's not a safety concern).
If we did use it, we would velcro it to the plates, so I didn't add mounting holes.
And if we ever make this gearbox, it will be in a few weeks to months at best. I'm one of two machinists, and the other one can't work for a while due to school. Mainly I put it up on CD to get opinions and release the CAD.

Thanks for posting the CAD!

[asid61]

Originally Posted by Dunngeon

Thanks for posting the CAD!

No problem. Though you should double check the gear spacing and the belting if you do decide to use this. I only gave 0.001" clearance on the gear spacings, and some of the parts are difficult or time-consuming to machine (read: shifter shaft).

EDIT: Also, you'll need to fix the output shaft to your specification. Right now it's necessary to use a roll pin I think, and those are hellish to get in apparently.

EDIT2: You can't use this with a 3.25" wheel. When at the lowest tension point, it intereferes. You have to use a 3" colson for this to be effective, or greatly increase the C-C distance of the motors. I'm reuploading the corrected CAD files right now.

[asid61]

Redid the gearbox to use 24t pulley in place of 26t, so that a 3" wheel can be used and not interfere with the cims. A 3.25" wheel will not work. The speeds are the same as before.
Weight is 1.75lbs, because I extended the output shaft a little bit so that you can use a 10-32 screw like a roll pin to keep the second shaft in place. You can also use e-clips to constrain the secondary shaft if you like. There was also an error with the shifting shaft spacing which was fixed.
Reuploaded to the Google Drive folder at the top.

[RonnieS]

Anyone wan't to post the link to the 2014 192 thread on theirs?
-Ronnie

Never mind, found it quickly on accident haha.

[asid61]

Originally Posted by Ronnie314

Anyone wan't to post the link to the 2014 192 thread on theirs?
-Ronnie

Never mind, found it quickly on accident haha.

In any case, here it is for those who want to see it:
http://www.chiefdelphi.com/forums/sh...d.php?t=126357

[mplanchard]

A beautiful model. Well done. Marie

[asid61]

Originally Posted by mplanchard

A beautiful model. Well done. Marie

Thank you!

[asid61]

Reuploaded with a few marginal improvements including adding an encoder to the small shaft and a mounting hole pattern to match the vex ball shifters/ WCP shifters.