Multi Speed Dual Motor Gearbox

[tenfour]

Does anybody have any good plans for this item that integrate this years motors?

[George1902]

http://www.chiefdelphi.com/forums/pa... SC&sort=date

the white papers

team 116 posted a nice one that uses last years' motors... the CIM's are the same, and i'm sure with minimal effort it can be changed to use this year's drills.

keep checking back with that page, too... there are always people with great ideas sharing info in the white papers.

[dlavery]

Originally posted by George1083
http://www.chiefdelphi.com/forums/pa... SC&sort=date

the white papers

team 116 posted a nice one that uses last years' motors... the CIM's are the same, and i'm sure with minimal effort it can be changed to use this year's drills.

keep checking back with that page, too... there are always people with great ideas sharing info in the white papers.

We did update the design for our transmission to make use of this year's Bosch motors. It worked well in Annapolis (we sucked at Richmond, due to a broken weld that kept us from moving all day Friday). We are currently updating the white paper to reflect the new design, and will be posting it shortly (as soon as Stephen and I get around to finishing and cleaning up the drawings).

-dave

[dlavery]

OK, so I finally got my act together and cleaned up the last two drawings, and folded them in with the rest of our white paper describing of our updated gearbox design. The "Mark 2" version of our gearbox is smaller, lighter, has fewer moving parts, and is easier to manufacture than the previous version. It is also updated to incorporate the new Bosch motors included in the 2003 FIRST kit of parts. The updated design has been posted in the White Papers section of the board. We hope this is useful. Let us know if you use, or improve upon, the design. Have fun!

-dave

[Matt Leese]

Originally posted by dlavery
OK, so I finally got my act together and cleaned up the last two drawings, and folded them in with the rest of our white paper describing of our updated gearbox design. The "Mark 2" version of our gearbox is smaller, lighter, has fewer moving parts, and is easier to manufacture than the previous version. It is also updated to incorporate the new Bosch motors included in the 2003 FIRST kit of parts. The updated design has been posted in the White Papers section of the board. We hope this is useful. Let us know if you use, or improve upon, the design. Have fun!

-dave

I don't mean to belittle your work, but I must comment that during the Maryland State Fair Competition your robot seemed to have more than a little trouble moving. Now, I'm not sure if that has anything to do with the gear box or not but to me they seemed a bit related. So basically I'm wondering what was going on there.

Matt

[George1902]

We used this gearbox design successfully during the 2003 season in Richmond and Annapolis, and it performed well. We also used it this past weekend at the Maryland State Fair competition, when we were running and our treads weren't binding (due to a different, and completely frustrating, problem - next year we go with WHEELS!!!). Anyway, we hope this is useful. Let us know if you use, or improve upon, the design. Have fun!

-dave

That's what Dave posted in this thread earlier today. Based on that, I'd say it was their treads messing up, not the gearbox.

[Wetzel]

Originally posted by Matt Leese
I don't mean to belittle your work, but I must comment that during the Maryland State Fair Competition your robot seemed to have more than a little trouble moving. Now, I'm not sure if that has anything to do with the gear box or not but to me they seemed a bit related. So basically I'm wondering what was going on there.

Matt

This is my understanding of it.
There was a flange on one of the drive sprockets that got bent at the end of the day Saturday, and bent just about every match Sunday, causing the tread to come off and bind/tear at itself.

It was a problem getting the power from the output shaft to the ground, not within the gearbox.


Wetzel
~~~~~~~~~
Take it apart, get the bigger hammer.
Again

[dlavery]

Originally posted by Matt Leese
I don't mean to belittle your work, but I must comment that during the Maryland State Fair Competition your robot seemed to have more than a little trouble moving. Now, I'm not sure if that has anything to do with the gear box or not but to me they seemed a bit related. So basically I'm wondering what was going on there.

That's a fair question. As noted above, the problems we were having last weekend had to do with the treads in our drive system. One badly bent flange on a drive sprocket, and the treads worked their way off the sprockets (which were being driven by the gearbox) and jammed up against the sides of the drive system. Once the damage was done, we could never pound the flange back into the original configuration, so it just kept happening over and over again. But the gearbox kept working just fine all the way through. In a way, the problem was exacerbated by how well the gearbox did work - it was providing so much torque in low gear that the fiber belts in the treads were stretching, and that allowed the treads to climb up the flanges and get bound up. By the end of the competition, the treads were so chewed up they looked like they had been dropped in a meat grinder.

It was very frustrating because we knew what was wrong, and how to fix it, but did not have the replacement parts or equipment to effect the repair. So we just had to keep pulling the tread assemblies apart after each match and pounding things flat with a hammer and re-assembling as fast as we could, and then keep our fingers crossed that it would stay together for two minutes. As I said elsewhere, next year we go with WHEELS!!!

-dave

[Andy Baker]

Originally posted by dlavery
That's a fair question. ... But the gearbox kept working just fine all the way through. In a way, the problem was exacerbated by how well the gearbox did work - it was providing so much torque in low gear that the fiber belts in the treads were stretching, and that allowed the treads to climb up the flanges and get bound up. By the end of the competition, the treads were so chewed up they looked like they had been dropped in a meat grinder.

...

As I said elsewhere, next year we go with WHEELS!!!

-dave

Dave,

I know EXACTLY how you feel. My fellow teammates and I are growing very tired of treads. For the little advantage they give in traction and climbability, they also give many headaches, breakdowns and inefficiencies. Maybe we should start a "I hate treads" club.

Note to any designer wanting to do treads: be careful, they are very difficult to deal with. Team 45 has been doing treads for 4 out of the last 5 years (3 metal, one timing belt), and there are many issues to deal with. In my opinion, treads are not worth the effort.

Andy B.

[Matt Reiland]

Very interesting that everyone is also having problems with the treads. Last year we went after a similar design to team 61, since we were impressed by the power that it laid down to the ground. We started with the blue supergrip belts from brecoflex (also known as 'break o flex') and they started out OK in practice. It was quickly apparent that the grate was eating them away rapidly but it was too late to do anything about it. After the first regional at Buckeye, two treads had ripped in half, through the metal bands and everything, of course the team 45 tranny in low may have had a bit to do with it that never failed once and we beat on it non-stop. Then we ordered up the solid center belts for Great Lakes and they worked better however they didn't fit the pulley's nearly as well as the serrated center and they took some power out of the drivetrain, boke a few there. So we kept on and ordered yet more for Nationals and actually it is pretty good that we didn't make it to the finals since we were down to the last set of treads by the end of the competition. Strangely enough one other team had the identical treads there and offered them to us in a pinch (That's gracious considering how much they cost!). Looking back, we spent wayyyyyy too much on the stupid treads and I actually am not too happy with the Brecoflex belts anymore. I think we broke 8-9 total which with the sprockets came in somewhere around $2-$3k in treads. Team 902 had the best compound for this years game with the rubber cortex, and many teams with the red rubber had de-lamination problems. So even though they were a blast, I would think twice about the treads in the future especially BrecoFlex. (Also the lead times were pretty long on the belts)

If I had my way , I would build a subassemblies one that was interchangeable with inline wheels like team 25 and one with tracks like this year and then you can have either depending on the game. Perfect this setup with a robust transmission (I think I have seen one around here somewhere) and you WILL have a sweet start to the season.

[Raul]

Originally posted by Andy Baker
Dave,

I know EXACTLY how you feel. My fellow teammates and I are growing very tired of treads. For the little advantage they give in traction and climbability, they also give many headaches, breakdowns and inefficiencies. Maybe we should start a "I hate treads" club.

Note to any designer wanting to do treads: be careful, they are very difficult to deal with. Team 45 has been doing treads for 4 out of the last 5 years (3 metal, one timing belt), and there are many issues to deal with. In my opinion, treads are not worth the effort.

Andy B.

Holy Cow! I thought I would never hear this coming from Andy!

Don't give up - FIRST might just not be the same without a techno-tank drive. If I may be so bold, let me suggest something. Carefully analyze the problems you are having with your design, list it's strengths and weaknesses, and then decide if you can do something to overcome it weaknesses without compromising its strengths. This is what engineering is all about!

Our story:
In 2002 we did 4-wheel crab. It had some advantages and some disadvantages. Just ask some of my team mates - I was so frustrated by the disadvantages that I declared towards the end of the season that "we will never do 4-wheel crab again". So what did we do in 2003? We did 4-wheel crab. We simply determined that its advantages were too valuable to pass up. So, we just had to figure out a way to overcome the disadvantages/weaknesses. We did and we are glad we did.

Raul

[Andy Baker]

Originally posted by Raul
Holy Cow! I thought I would never hear this coming from Andy!

Don't give up - FIRST might just not be the same without a techno-tank drive. If I may be so bold, let me suggest something. Carefully analyze the problems you are having with your design, list it's strengths and weaknesses, and then decide if you can do something to overcome it weaknesses without compromising its strengths. This is what engineering is all about!

Raul

Raul,

Thanks for the encouragement. I do feel that if we would choose to do treads again, we would make them much better and learn from some mistakes during last year's season. We are not totally ruling out treads, we just don't like 'em much right now.

I agree that teams learn from mistakes and strive to make things better. We TechnoKats are not jumping to conclusions about drive trains until we see the kickoff.

Andy B.

[dlavery]

Originally posted by Andy Baker
...Maybe we should start a "I hate treads" club.

I have already started a movement to adopt this as our new team flag...





-dave

[Clark Gilbert]

I can see this evolving into something.....

Heck, you've got members, a flag, and EVEN a theme song.

Metallica - Don't Tread on Me

(it even sounds like a good anthem or theme song)

[MattB703]

Originally posted by Matt Reiland
Team 902 had the best compound for this years game with the rubber cortex, and many teams with the red rubber had de-lamination problems.

Yes, we actually had very good results with the Breco-flex belts and the Correx gum backing this year. We had to replace 3 belts in 3 competitions including playing in the finals. It could have been that we were using a single speed gearbox and we may not have been putting as much tensile load into the belt as some other teams.

A tip for teams looking at the correx gum. It did not work as well on the carpeting as the supergrip.

MattB
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