Dewalt transmissions

[Gabe]

What are people's experience with using DeWalt transmissions on their robot? I am looking into the possibility of using Dewalts with CIM motors to drive a robot and also shift speeds on the fly. The idea is very attractive but I am wondering how well they would hold up in competition. I have looked over in great detail the wonderful white paper on these transmissions, but still am left with questions on durability.

Pictures of the DeWalt transmissions on robots would also be very nice.

[Francis-134]

I don't have any pics of 40's robot on me, but I can tell you that our Dewalts held up very nicely over the span of two regionals, the championship and three offseason events. Occasionally, you may need to perform some minor maintenence (tightening screws and reapplying locktight), but nothing major has gone wrong for us.

[ajlapp]

simple answer, they are amazing.

we have beat the tar out of them for two seasons without a failure.

we used them in 2006 with the large cims and in 2005 with the small. we shift them on the fly and they always perform.

but to be honest, after seeing how some robots performed last year using the kit tranny, we may not use them again.

[Dick Linn]

These folks may have mounts and upgrade parts that are of interest to anyone using Dewalt trannies: http://www.dcwaterjet.com/dustin.shtml

Trannies and output shafts: http://www.robotmarketplace.com/marketplace_dewalt.html
http://www.robotmarketplace.com/marketplace_dustin.html

[EricS-Team180]

SPAM has had excellent results with them over the last 2 seasons, and I would not hesitate to recommend them. We do have to watch the adjustment of the lever arm we use, to attach the shifting servo to the shift mechanism. It tends to get out of adjustment over the course of a day of competition, and we will not always get 3rd gear. Other than that, they are solid.

Eric

[Ben Piecuch]

We used Dewalts for the 1st time last year. We were extremely happy with them, and didn't really have any major problems with them. We did find that the press fit gear on the CIM output shaft actually moved on us (slid inward) and we lost one of the gears due to this.

(The press fit gear is a cluster, and the larger teeth failed to mesh with the lock-out ring for 3rd gear.)

Other than that, they shift quite smoothly and were relatively cheap. However, I think we'll go back to the kit tranny for this year. It took almost 3 weeks to get the parts machined, assembled, and tweaked. That's far too long to wait for a drivetrain. We're also looking at some similar two speed drill gearboxes. No details as of yet, but we found that the 3rd gear wasn't all that useful on the Dewalt, even with full runs across the field.

Here is are a link to our '06 pictures. I think weeks 3 and 4 of the build pages show most of what you're looking for. You'll also see the custom mounts we made, which was required to run one length of continuous chain.

GUS '06 Photo Album

I can snap some more pictures of the gearboxes if required. Best of luck!

BEN

[Bill_Hancoc]

Ours were great...we had four, one driving each wheel and we had excellent pushing power and speed...the only problem we had was not related to the transmissions them selves so i wont even put it here....they did tend to put out smoke tho when you shifted them and held the shifter in between 2 gears for too long but other than that excellent

[yodameister]

We used them this year. Our team was not impressed at all with the Dewalts. Our being a rookie team may have had something to do with it though. We had problems with the pressed on gear spinning. The problem was solved with using a key. We seemed to lose some of the gears (most likely out of adjustment). Next year we will most likely be using the AM 2 speed (depending on the game of course).

The premise of the trannies is really good, and we were very excited about using them as so many teams had success with them. I suspect if we had more experience with them, we would use them again. They did shift nicely and the gearing was appropriate to this years game. If you use them, don't be afraid of the miserable noise they make when shifting, we saw no damage to the gears after 3 regionals of use. The noise comes with the terrotiry.

I hope this helps, and the best to you and your team this year.

[Starke]

Team 340 used the DeWalt 3-speed in 2005, and I posted a report about our experience with them here .

[Fritztopher]

We used the dewalts with the small CIMs this year (based on the NBD white paper), and we never got them to work right. We had major problems with the sun gear at first, and we actually cracked one while modifying it. Then we couldn't get them to mount properly on the robot, and we ran into problems shifting. It might have worked if we had had enough time to get them to work, so I would definitely recommend tinkering with them in the off-season before deciding to use them on your robot. Given the time it took to get them to work halfway, we will not be using them again.

[fimmel]

team 885 is trying them now for next year......we havet got them yet (backorder) but i hope all goes well
/forest

[Jack Jones]

Originally Posted by Fritztopher

... We had major problems with the sun gear at first, and we actually cracked one while modifying it ....

A common malfunction, so I hear, even for veteran teams.

This design is one way to do away with removing the planet axis pins, drilling the sun gear, and pressing the top-hat onto the CIM shaft. No press fits are necessary. The adapter slides onto the CIM's shaft, and the four holes slide onto the planet pins. We (1213) water cut ours from 0.25" stainless, which is how we can leave the key in the center hole. But they could be cut from carbon steel, drilled, and notched to accept a piece of key stock. We ran them at all four corners for over 150 matches and many many hours of practice without any problems.

[woody]

We used the dewalts this year and were quite pleased with them. We only noticed two minor difficulties, both of which were at least partially our fault:
1. The yellow case MUST remain on the transmission. If its not there, the plastic shifter piece expands and can pretty much render the transmission useless. It always helps to read the directions : )
2. The mounting plate for the shifter servo needs to be fairly rigid. We ended up using some .030 or similar aluminum and bent flanges along the edges to strengthen it a bit.
Overall they are pretty reliable and you cant beat the light weight. Plus they're not too terrible to modify for use with CIM's.

[ebmonon36]

I also can give nothing but praise for the Dewalt transmissions with the CIM motors. Over the last 2 years that 1018 has used them, I don't recall any major problems with them. The only thing that I recall ever going wrong was the left hand screw on the end not being tight, but that has nothing to do with the transmission itself. Once the servos were programmed, shifting was very easy to do. This has been a very reliable drive train, and I would highly recommend it.

ERic

[JagWire]

I also would have to chime in that the DeWalts are awesome. my team had a little trouble with machining the sun gear if i recall correctly, since they are rather hard, but we got it done. the only other issue we had was when we pressed the sun gear onto the CIM, on one of our motors we ended up pushing the shaft in the CIM and fractured the armature. not exactly a cheap mistake, but we lived.

once they were put together and everything was programed they were awesome. we were a rookie team last year, and, thanks to a lot of great expertise on board we didn't have a whole lot of trouble with them. i'm quite sure we'll be using them again this year also in all likelihood.