View Full Version : pic: Ahhhh, that's better.
[cdm-description=photo]39097[/cdm-description]
Andrew Lawrence
04-07-2013, 21:00
The new set of gears are looking pretty good! Quick question - why did you choose to have a gear-driven drive instead of the conventional chains/belts? Do you feel like the added complexity/weight/inefficiency (if any) hindered your driving?
Akash Rastogi
04-07-2013, 22:28
Looks shiny. I'm excited to discuss any pros and cons you experienced with this setup while at IRI in a few days. See you guys there!
cbale2000
04-07-2013, 22:51
Reminds me a little of our robot from 2007 (http://www.chiefdelphi.com/media/photos/26312). While I can't speak to the efficiency of using gears, I do know that it was by far the most powerful drive system we ever built, and to this day have yet to build a robot with chain drive that can match it.
On a different note, are those VexPro gears you're using there?
Clem1640
04-07-2013, 23:16
Now, that's a lot of gears. Shiny. But it also looks heavy. Why gears for your power transmission in lieu of a lighter approach?
The new set of gears are looking pretty good! Quick question - why did you choose to have a gear-driven drive instead of the conventional chains/belts? Do you feel like the added complexity/weight/inefficiency (if any) hindered your driving?
Not new gears, the same gears that have run trough 4 different competitions just cleaned up and ready for more.
Looks shiny. I'm excited to discuss any pros and cons you experienced with this setup while at IRI in a few days. See you guys there!
See you there.
On a different note, are those VexPro gears you're using there?
Yup all VexPro
Now, that's a lot of gears. Shiny. But it also looks heavy. Why gears for your power transmission in lieu of a lighter approach?
Everyone assumes that gears are heavy and inefficient but each drive half weighs less than 13 pounds including motors.
The why is simple, their bulletproof! No chains to fall off or tension, no sprockets to skip. These never failed us, even when something hard fell into the gears (see previous photos) it just kept on blazing.
We have been wanting to do this for years, the smaller footprint of this years game and the introduction of the much cheaper VexPro gears made it possible.
Now might I ask; is the amount of friction that the idler gears add noticeable?
Oh and a big thanks to Mike Trapp at Waterjet Cutting of Indianapolis for providing the material and cutting of all the parts that made this possible (including two different iterations and a practice robot) and inspiration from 3940 CyberTooth and AndyMark from their rookie year robot.
Now might I ask; is the amount of friction that the idler gears add noticeable?
The drive is the most quiet and smooth drive we have ever used and I challenge anyone to find a quicker or faster robot this year.
dtengineering
05-07-2013, 01:31
Nice setup! We built an 8 wheel drive using chains in 2010... and seeing this has me thinking that we should have used gears. In fact a 10 wheel drive would be "almost trivial" to implement using a design like this.
Hmmm.....
Jason
AdamHeard
05-07-2013, 01:51
Assuming those are 44, 50 and 60T gears. That's only 1.36 lbs per side in gears. This could easily be cut in half w/ basic dishing of the gears on a lathe (or not ideally, a mill).
There is some what tied up in all the shafts/bearings for the intermediate gears. Assuming 2 FR8's per axle, and aluminum shafts at 2 inches long, this is .86 lbs per side.
This isn't a crazy amount of weight to cleanly solve the problem.
The drive is the most quiet and smooth drive we have ever used and I challenge anyone to find a quicker or faster robot this year.
Bold statement. I would wager 254 was quicker for sure.
runneals
05-07-2013, 02:03
What are the specs on this baby? FPS? Looks like something Aren_Hill might enjoy! :D Can't wait to talk to you more & see it in action at IRI!
DampRobot
05-07-2013, 02:10
This might just be me being blind, but is the way those idler gears rotate just a frictional bearing between an aluminium round shaft and the hex on the gear?
Just curious, I'm happy to take your experience at face value, but did you happen to run any tests of this drive train compared to a similarly geared belt or chain one, in terms of efficiency or speed? I'm a big believer in chain/belt drives, but I can certainly see the advantages to this type of drive, especially if the efficiency is as high as other drive types.
Any plans for integrating some sort of reduction into those idler gears? You could probably make those side rails with a slick little integrated drive gearbox. It would be almost like 610's setup, but with gears instead of chain.
Ahhhh Steampunk drivetrain. Love the gears and the different sizes.
I was pleased to hear that it's a custom frame supporting them, so there is the quiet whirr of fully meshed gears vs mismatched gears or chains rolling around. So you've built the Rolls Royce of 6 wheel drive.
Can you say a few words about lubrication at the shafts and at the gear faces?
Bold statement. I would wager 254 was quicker for sure.
I'll stand by it :)
What are the specs on this baby? FPS? Looks like something Aren_Hill might enjoy! :D Can't wait to talk to you more & see it in action at IRI!
17.3 free speed. It was as fast as we dared go on a 90lb robot without fearing constantly tripping breakers.
This might just be me being blind, but is the way those idler gears rotate just a frictional bearing between an aluminium round shaft and the hex on the gear?
Just curious, I'm happy to take your experience at face value, but did you happen to run any tests of this drive train compared to a similarly geared belt or chain one, in terms of efficiency or speed? I'm a big believer in chain/belt drives, but I can certainly see the advantages to this type of drive, especially if the efficiency is as high as other drive types.
Any plans for integrating some sort of reduction into those idler gears? You could probably make those side rails with a slick little integrated drive gearbox. It would be almost like 610's setup, but with gears instead of chain.
All shafts are on bearings and no comparison testing was done. There is reduction built into the gear arrangement and it's driven by a custom single reduction gearbox. The reason we ran 4" wheels for the first time was to reduce the reduction needed.
Ahhhh Steampunk drivetrain. Love the gears and the different sizes.
I was pleased to hear that it's a custom frame supporting them, so there is the quiet whirr of fully meshed gears vs mismatched gears or chains rolling around. So you've built the Rolls Royce of 6 wheel drive.
Can you say a few words about lubrication at the shafts and at the gear faces?
Well we are sponsored by Rolls Royce :)
You can see the lubrication we used in the picture.
MrRiedemanJACC
05-07-2013, 09:16
Is there a shifter in there also? Or are you a single speed drivetrain?
Aren Siekmeier
05-07-2013, 10:02
Is there a shifter in there also? Or are you a single speed drivetrain?
At 17.3 fps I hope so...
Akash Rastogi
05-07-2013, 10:56
Is there a shifter in there also? Or are you a single speed drivetrain?
It is single speed.
http://www.youtube.com/watch?v=OVkDHDV4Tvo
Ryan Dognaux
05-07-2013, 11:00
This picture you posted earlier (http://www.chiefdelphi.com/media/photos/38466) was still one of my favorites from 2013. The drive looks great, any chance we could see some CAD for it at some point? I will definitely be checking out this one at IRI.
I noticed from the first rev and the video that Akash linked to that you had problems mounting the single speed gearboxes. Any more information on what the problem was?
DampRobot
05-07-2013, 12:03
17.3 free speed. It was as fast as we dared go on a 90lb robot without fearing constantly tripping breakers.
All shafts are on bearings and no comparison testing was done. There is reduction built into the gear arrangement and it's driven by a custom single reduction gearbox. The reason we ran 4" wheels for the first time was to reduce the reduction needed.
This would seem to imply single speed. I would be very interested to see a shifter for FRC that only needed a single reduction.
jman4747
05-07-2013, 18:50
This is an awesome drive train I love the breaking of convention and getting away from the same way of doing things. So Ahhhh indeed this is a marvelous breath of fresh air.
How did you attach the wheels to the drivetrain? A picture would help.
How did you attach the wheels to the drivetrain? A picture would help.
Offhand, I'd go with the wheels sliding onto the hex shafts (from left, the 1st, 5th, and 9th gears) and being held on by a washer attached to the end of the shaft by a screw into the end (note the tapped holes in the hex shafts).
Offhand, I'd go with the wheels sliding onto the hex shafts (from left, the 1st, 5th, and 9th gears) and being held on by a washer attached to the end of the shaft by a screw into the end (note the tapped holes in the hex shafts).
Exactly, we have run cantilevered shafts for four years now and this is how we have always attached them and never had a problem. One Button head screw and easy change.
Hmmm: Indiana Team - Lucas Oil Product Placement in photo....
Could Lucas Oil become an IRI sponsor? Could we use their stadium for IRI? or Champs?
Peyton Yeung
08-07-2013, 14:32
Hmmm: Indiana Team - Lucas Oil Product Placement in photo....
Could Lucas Oil become an IRI sponsor? Could we use their stadium for IRI? or Champs?
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