pic: Team 192's 2012 Gearbox

[ttldomination]

Nice render, oh wait...

Is that red delrin? Or just a really flat red paint on Aluminum?

- Sunny G.

[Gray Adams]

Originally Posted by ttldomination

Nice render, oh wait...

Is that red delrin? Or just a really flat red paint on Aluminum?

- Sunny G.

It's all bead blasted and anodized aluminum. The shaft is steel, and the bottom dust shield is 5052.

[Ty Tremblay]

Assuming your worm reduction isn't backdriveable, how does the drive train react when you try to stop fast? The nature of worm gears to be non-backdriveable would make your robot very difficult to push, but also makes it so that you can't coast to a stop.

Do you "coast" via software? Or did you determine that you won't snap any gear teeth off?

[Joey Milia]

Yes this Gearbox is for our drive train
and
Yes it is for a WCD

Originally Posted by Ty Tremblay

Assuming your worm reduction isn't backdriveable, how does the drive train react when you try to stop fast? The nature of worm gears to be non-backdriveable would make your robot very difficult to push, but also makes it so that you can't coast to a stop.

Do you "coast" via software? Or did you determine that you won't snap any gear teeth off?

The worm is a high efficiency 4 start gear. It is backdriveable, albeit with higher resistance than a spur gear gearbox. If they were not backdriveable, we would not be using them due to risk of the worm gear teeth shearing when we get hit.

The purpose of this gearbox is not to make it hard to push, but to make it small and have the cim's parallel to the sides of our frame.

On an off season prototype, we had victors set to brake mode and it worked really well. However, we have set the victors to coast not because of the gearbox, but because of weight distribution in the rest of the robot.

[Sb28000]

That's a really intriguing design, nice work guys. I was wondering to myself if anyone had ever oriented their CIMs on another side of their gearbox other than directly across from the output shaft (I was thinking about putting them on the same side as the output shaft, just as an idea to maybe save space and work on as a CAD challenge). But that's a really cool solution to the challenge of saving space on the bot.

[IndySam]

Wow that's really sweet, congrats!

[msimon785]

That's amazing. Nice job!

[akoscielski3]

Would i be able to get a CAD model of this? I'm guessing you have one considering its so nice. I have no intention of stealing your design or anything, just want to look at how it was made and such. More pictures would work too, but i would rather have the CAD.

Thanks

[Lee Reed]

This is a beautiful gearbox. An idea worth stealing for next year. By the way how did you hob the worm wheel?

[Joey Milia]

Thank you all for your praise

Originally Posted by akoscielski3

Would i be able to get a CAD model of this? I'm guessing you have one considering its so nice. I have no intention of stealing your design or anything, just want to look at how it was made and such. More pictures would work too, but i would rather have the CAD.

Thanks

My intention is to publish the CAD model of the gearbox on FRC designs sometime soon after build.
I will also be releasing a write up about the design process as well as the choices I made and the reasoning behind them.

Another note on the Gearbox. It was originally designed in the spring/summer of last year and two prototypes were made in the fall. It was then refined and modified for the 2012 FRC season.

I did all of the design work on it and everything but the dust shield was manufactured by myself or other fellow students on our team, a large portion of which was done on our CNC mill.

By the way how did you hob the worm wheel?

If you mean how did we cut the worm gear the answer is we didn't. Both the worm and worm gear were purchased from Motion Industries but they are also available from sdp-si.

[Bruceb]

Did you use a worm to get the reduction you wanted to to change the output angle? OR Why did you not use bevel gears?
Been thinking about a right angle drive for years just get the cims out of the way.
Bruce

[DampRobot]

To me, it seems like mounting the CIMs sideways would be more trouble than it's worth. Although it certainly is a beautiful gearbox and cool design, I've never really been concerned with CIMs taking up too much room in the center of the robot.

Also, if I remember correctly, worm gears are fairly inefficient, even with four tooth worms. Do you know how efficient the gearbox is compared to, say, a toughbox?

[notmattlythgoe]

Is the one motor just supposed to run backwards, or did you gear it to reverse it's direction?