Our robot experienced the bow-tie effect on the new 3rd edition carrier plates for the Banebot 56mm transmission. We caught it before it failed totally. There was no indications that it had loose pins like the 2nd edition carrier plates. However, it only lasted five rounds with the new harder plates.
Did anyone else have any problems?:ahh:
We had problems with one of our gearboxes, but this was a new gearbox that we had not added washers as spacers. Once we added the washers everything worked again. We started looking for other banebots 56mm and we found that few teams had issues at the championship. Most of the teams in Galileo had working banebots. Most teams never had a problem thoughout the entire FIRST season because they performed preventive maintenance (adding washers, changing the carrier plates).
I was also impressed with the number of teams who used banebots for the arms and joints for many different functions. Banebots has come into the FIRST community in a much different way then many of the accepted FIRST companies . Overall, banebots should continue to provide for the FIRST community for years to come. What FIRST actually puts into the KIT next year, I think it should have some type of shift mechanism, either dewalts, andymark, or banebots (with shifting).
We didnt see any noticeable problems with them, but to be safe we decided to take them off our robot and replace the carrier plates after our last practice round on thursday. This was the worst decisision ever! It took us 3 hours to take off the gearboxs, they keys and sprockets had gotten stuck on the shafts and we ended up having to make a little tool to press them out. When we did get them off there was no visible damage at all inside the gearboxs (we were running only 1 CIM). We replaced the plates anyways and put them back on the robot. We were there until 8pm on thursday and spent the first 2 hours of Friday putting it back together. When we got it all running again the right side kept binding up and it made it real hard for our driver to go straight and turn at all. So we took it off again during a 2-3 hour break between matchs, this time we didnt remove the shaft from the drivetrain but just the motor and most of the gearbox. I went arround and asked about 15 teams for a gearbox until I found one that had a spare (most teams had already given them away to other teams). We ended up not using it because the inside of the gearbox worked fine after we cleaned it out, so i gave it back on Saturday (Thanks 1732!).
What a nightmare.
I know this may not be the best thread to post this in, but the information is quite appropriate for this thread.
During the Davis regional, we burned up two CIMs and damaged two 56mm trannies. Ultimately we figured out the root cause and made a modification to our bot to stop the problem from re-occurring a third time.
During build season, we determined that adding the outboard drive shaft support bearing would be a really good idea. After receiving the bearings, we fabricated to mounts and put them on our bot. We didn’t notice until the second time we replaced a motor and tranny that when the support bracket was assembled to the bot that it didn’t actually support the end of the shaft (long story that doesn’t need to be spelled out here). Needless to say, the student who installed it the first time said, “oh, I was going to fix that later, but forgot.” That aside, without the support, the output shaft was being pulled off axis.
Inside the trannies, the output shaft has a short extension that protrudes into the center of the final sun gear. The clearance of this fit are quite small. Once the shaft is pulled off axis, the little extension rubs against the inside of the sun gear. No amount of lubrication is sufficient to dissipate the friction this causes. The resulting heat and binding caused the sun gear to seize onto the output shaft. As you might imagine, really bad things happen when the final stage of a planetary gear system becomes fused together.
So, how do you fix this problem?
Bore out the sun gear to allow plenty of clearance. Make sure the end of the output shaft is properly supported!!!
Once these two steps were completed, we had no further problems with our drive train.
BTW, this happened with a hardened carrier plate as well as with the original plate.
I have to respectfully disagree. I think the point of including the transmissions is to give underfunded or beginning teams a cheap and basic way of getting a team on the field. They do not need the extra cost of the shifting mechanisms for that.
We had continuous problems and breakdowns with the banebots transmissions. For example, during a final match in Colorado our bot received a lot of torque from another robot and our transmission broke. We couldn’t do anything about it in time and lost the regional… We’re switching over to AndyMark or making our own transmission next year. We switched out both transmissions on Thursday in Atlanta and the robot did not break down.
Experienced problems:
- Rounding out the “double d” plate
- too much pressure was put on a shaft and the inside was destroyed
- brass gears were stripped
Going in the other direction: We saw very minor deformation of the carrier plates, noticed only while we were installing the new ones BaneBots so generously supplied. The robot then went to three competitions (NJ, Buckeye & Championships) without any failures or problems. We even won 2 Motorola Quality awards, ‘cause nuthin’ broke.
We have four CIMs driving one transmission each. The ends of the shafts are supported. Each shaft has 2 sprockets, each driving one of the six 6" IFI 2" wide traction wheels, all on a Kitbot chassis (the middle wheel is driven redundantly by other trannies). Final speed was about 11.5 fps. We climbed every ramp, did not lose any pushing matches (but tied a few times) and played defense mostly.
Overall, we are very satisfoed with BaneBots and their products.
Don
Whether or not you experienced problems, the banebots have been proven unreliable.
If I were designing a single speed drivetrain to run off of one, or two small CIMs I would use the AndyMark single speed gearbox.
Not only is it cheaper (when running two CIMs), it is lighter and much more versatile. It can run a Big CIM without any modifactions and with a little ingenuity, it can be modified to run 3 or 4 of the following motors; Big CIM, small CIM and fischer price in the AM planetary.
For $98 and 2.91 lbs, I don’t understand why ANYONE would choose the banebots over the AM planetary.
Two shifting gearboxes would be more appropriate than two single speed gearboxes if that’s whats included in the flat rate kit and hopefully the $6K registration and kit fees do not increase.
If you are refering to the cost to replace the shifting hardware, I think that cost would be less than $50, as long as the gearboxes are reliable, I don’t think upgrading to shifting gearboxes will be a monetary burden on most rookie teams. I’ve been on two rookie teams so far and shifting was something both rookie teams wanted but we just went with what was in the kit.
We used 4 of the transmissions, one for each wheel, no chains. We did have to do some service, but this was pretty easy because each wheel is an independent unit. By having such a simple drive we were able to climb ramps easier than many and invest our time and money in a versatile effective arm for scoring.
What were you guys with damaged BB gearboxes using them for?
we had a direct drive to the wheels no chain, and yes, all of the robots weight was on the shaft. we went through build, practice, and our regional without problems, I just took one box apart, and it was perfect, no sign of warping bow tying or loose pins on either plate. and, they are the original “recalled” plates.
and because we were a defensive robot, we did a significant amount of pushing, quick bursts of power from forward to reverse and other damaging things to them. they are still fine.
in my opinion, the BB gearboxes are the best gearboxes first has given us, I highly disliked 2005-2006 2 motor gearboxes, and the terrible grinding noises they were known for making.
I have to disagree that the banebots have “been proven unreliable”. Sure… with the original carrier plates there was a flaw. It was a very frustrating flaw. Believe me… we had four of the transmissions and wrecked them three weeks into build, and they failed in a very frustrating manner. Once we put the new carrier plates in, however… zero problems through two regionals.
This, by and large, has been the experience of the vast majority of teams using the BB 56mm trannies. The ability to use the trannies as direct drive to the wheels, as opposed to chain drive, actually makes them MORE reliable in the context of an overall drivetrain solution than many of the KOP solutions we have used in the past.
Perhaps even more important is that Banebots, the company, has been PROVEN to be reliable and to stand behind their product, even at considerable expense.
I will definitely be buying from Banebots and using their products in the future.
Jason
I think it would be worthwhile, now that the crisis of getting replacement carriers to hundreds of teams is over, for BaneBots to do a very serious case study (with FRC teams) of the problem. It seems like there have been mixed results the whole time, but if there were a particular set of conditions that consistently led to success or failure, these would be good to at least document.
I know Joe Johnson started on this during the build season, asking for feedback from teams that had problems, but I think now that the season is over, it could use a more thorough revisit and I think the teams that used BaneBots products, for better or for worse, would be glad to help.
Personally, I would like to see BaneBots return next year with an improved product. I like the planetary option for drive gearboxes for many of the reasons mentioned above. I bit my nails for two months, but in the end the four BaneBots gearboxes we used all survived (with some modifications that I would like to see made stock in next year’s models).
We had the 56mm Banebot transmissions on our 6 wheel drive
robot, using the two motor adapters and 12:1 gear ratio.
We competed at three regionals and the nationals, with some
very aggressive defensive play at times.
We replaced the carrier plates and shafts with 4130 steel,
using a square drive for broach cost reasons, that we heat
treated in our shop and had no problems with our transmissions.
We also broke the transmissions in with no load, in both directions,
and then fully cleaned and lubed them prior to any hard use.
I think that Banebots needs to give some careful attention
to the details on the carrier plate and output shaft, and
these transmissions will be just fine for next year.
Eugene
The banebots have been Proven and in some ways they have a much wider selection and different sizes then most gearbox manufacturers. If FIRST wants to add another another company (gearbox) to the kit, that’s great. However I think FIRST should continue to allow banebots gearboxes.
If you can do it with a simple spur or sprocket reduction, or by using an Andymark product, avoid the banebots.
I guess you can say they are reliable enough. But the huge variances among them, and the fact that the AM products I’ve used have far fewer failures (if any), convince me to avoid them.
Really, it’s a matter of doing something possibly more easily at first, at the risk of having to completely overhaul it later.