View Full Version : Anyone lost thier BaneBots Carrier pins?
During our last match today, we lost one side of our drivetrain, and were unable to drive around. When we took apart the BaneBots gearbox, all 5 of the pins in the carrier plate had come out of the carrier plate, so that the output shaft spun freely. :eek: This is with the new hardened carrier plates, in a 2-CIM 12:1 gearbox.
Has anyone else had this problem?
I did notice that when I put the new plates in that they were really just pins stuck inside a through hole, unlike the other plate which had pins in a partial hole. Thanks for getting this out, now it ours fails I'll know what's wrong with it.
Andrew Blair
02-03-2007, 21:26
Banebots, in a hurry to get these new carrier plates out, had to substitute a standard pin that they could easily obtain in place of their own, longer pin. Therefore, the pins are a bit shorter. I guess the lack of engagement inside the hole is allowing the pins to back out in operation.
I suppose teams should press the pins back out and use some press-fit loc-tite to retain them. That seems like the easiest solution. Any team with an arbor press should be able to take care of it in a few minutes.
Richard Wallace
02-03-2007, 21:32
There was one report of this problem from a team at St. Louis. I believe the team was 525. Hopefully someone from that team will provide more details.
From what I heard this happened to our team (I'm a programmer, but I think this is what happened.)
We have pictures of the carrier plate somewhere...
I wasn't there when it happened, but we apparently lost the pins on the other side this morning. We had been playing a lot of defense. Unfortunately, there's no good way to check for the problem without taking apart the gearbox, and when it fails, it fails completely.
We had noticed difficulty making left turns sometimes, and backing up made the problem go away. This might be a warning sign, but we need more evidence to prove it.
I wasn't there when it happened, but we apparently lost the pins on the other side this morning. We had been playing a lot of defense. Unfortunately, there's no good way to check for the problem without taking apart the gearbox, and when it fails, it fails completely.
We had noticed difficulty making left turns sometimes, and backing up made the problem go away. This might be a warning sign, but we need more evidence to prove it.
Yes. BOTH of the BB transmissions on our robot failed during the course of one regional. They failed in exactly the same way and likely cost us a qualification round. We had the second one fail on us during the QFs. Fortunately, because of good planning and an amazing display of teamwork, we were able to swap out and install an spare transmission assembly in between matches. Our drivetrain is a 6 wheel-drive using the KOP wheels with the center wheels lowered.
Well, I guess we won't be using these transmissions next year.
We will pull them out and rebuild them for our next 2 competitions.
Does anyone know the precise diameter of the pins?
I think if we insert a short pin into the top of the planetary gear, this may prevent the longer pin from coming out, in addition of course to putting some thread locker on the ends of the long pins.
Robo_Coyote
04-03-2007, 23:08
Team 1323 had one of our transmissions lock up. We were running the two CIM adapters to the kit banebot transmission with a new carrier plate and the spur gear in the center had pushed the inner carrier plate out and was making the Global Gears bind. Team 1778 in the pit next to us had this happen twice with two different Transmissions and they were only running one CIM to them. Anyone else have this problem
Bruce Newendorp
04-03-2007, 23:14
We had the same problem - the pins came out of the new carrier plates and one of the planet pinion gears stripped. I posted a long explantion on this Our Banebots Experience (http://www.chiefdelphi.com/forums/showthread.php?threadid=54806) thread.
sanddrag
04-03-2007, 23:20
Anyone else have this problemWe had this happen in testing. Locked up so bad couldn't turn it with a 5" wheel on it. Single CIM, 40lb bot, slippery surface. Took it apart, greased, put back together, ran like butter.
Uberbots
05-03-2007, 21:40
Yes, it has happened to us, multiple times. Those carrier pins shoot out after less than an hour of driving on our robot- and we are simulating competition defense. This really is not good.
JohnBoucher
06-03-2007, 05:28
Yes.... In NJ we took them to the machine shop and had them spot welded. That seemed to hold them for the rest of the regional. I don't know if that fix will last.
Daniel_LaFleur
06-03-2007, 07:27
My biggest concern here is that we've replaced a predictable failure (increasing backlash until the double d fails) with an unpredictable failure (pins pulling out of the carrier plate). If this is the case we have made a bad situation worse and almost makes me want to consider keeping the weaker carrier plates.
Elgin Clock
06-03-2007, 10:30
From what I heard this happened to our team (I'm a programmer, but I think this is what happened.)
We have pictures of the carrier plate somewhere...
I'll get them pics up tonight for all to see.
Basically in the high stress situations inside the transmissions, the pins holding the carrier plate to the gear array slipped right out of the plate. Slip fit pins anyone? :(
Not good.
Yes.... In NJ we took them to the machine shop and had them spot welded. That seemed to hold them for the rest of the regional. I don't know if that fix will last.
That was our fix, and I'll post a pic of that as well for reference.
MrForbes
06-03-2007, 16:22
it's my understanding that the pins on the replacement plates are shorter than the originals....has anyone tried simply taking the pins out of the original plates, and putting them in the new plates?
maybe that's too easy....
Richard Wallace
06-03-2007, 16:32
it's my understanding that the pins on the replacement plates are shorter than the originals....has anyone tried simply taking the pins out of the original plates, and putting them in the new plates?
maybe that's too easy....I think the problem is not short pins, it's over sized holes. The pins do not interfere sufficiently with the holes, so they walk out under load. Fatter pins won't work because their diameter has to suit the planet gears, so the only fixes are to (1) remake the plates or (2) somehow retain the pins in the existing holes; some have suggested using Loctite, others spot-welding. The latter has proved reliable enough for one event, so far.
edit: I have heard one additional suggestion. Since the pin holes are actually tapered, larger on the gear side of the plate, it might be possible to press them through so that they extend on the opposite side and thereby make the fit more secure. Then the plate could be installed "inside out". Don't know if that would help -- the spot welding idea seems better to me. /edit
MrForbes
06-03-2007, 18:06
are the pin holes tapered before the transmission is put to use? maybe they get tapered as the pins move around?
anyways, the pics I saw of the new plates show the pins are not pressed in all the way, and I believe this is because the pins are too short. every team has(had) the original long pins...don't cost nothin to try them....
Richard Wallace
06-03-2007, 18:25
On the spare carrier plate subassemblies I saw at St. Louis (AFAIK there should be spares available at each event) the pins were pressed in flush with the back side of the plate. We tested one by applying light hammer force to a punch and it popped right out. We gaged that hole and measured that pin diameter, and concluded that at least some of the holes have insufficient interference fit to the pins. It is true that the measurement of hole taper was made after removing the pin, so that may have had some effect; however, the same taper was apparent in a "new" part and in one that had failed after short use.
sanddrag
06-03-2007, 19:36
I noticed the new plates have a letter stamped into one side (was it a K ?). Does anyone know what this means?
Anyway, this may be the perfect application for Loctite 680 retaining compound. It is great stuff. It took a torch and an arbor press to get off a gear on a CIM that was a slip fit on that had a drop of that stuff on it. Just make sure surfaces are relatively clean. (no grease).
BuzzRobotics, Team 175, has been on this potential problem of loose pins on the new carrier plates. We have been using the original carrier plates, and have only suffered minor distortion of the double D drive hole. We are only using a single CIM with sporadic use of the Banebot in our secondary drive, so we are not expecting trouble. But to prepare for the future, we anticipate installing the new hardened plates. To prepare them, we are installing 4 mm X 16 mm hardened dowel pins into newly drilled - reamed holes for a good press fit, and then resize the length to the original carrier plate pin length. We don't feel loctite will stand up in the oversized holes, and are afraid of distortion from welding. In the meantime, the new Banebot transmissions will have a 2nd revision of the carrier plates already installed when they become available, according to a conversation with an engineer at Banebots. If you make new holes, you could use the pins from the original carrier plate that are the proper length, if you can't obtain new pins. Make your own choices.
Why is there never enough time to do it right, but always enough time to do it again???
Ben Piecuch
07-03-2007, 14:37
Hodge,
I'm a little confused with what you're doing with the trannies... As I understand it you're doing the following:
- Using the replacement carrier plates, but discarding the pins
- Drilling New Holes for new dowel pins
- Rebuilding this modified carrier plate with new pins?
Is this correct? Also, you said that there is a possibility that Banebots is shipping out ANOTHER revision to this carrier plate? (I haven't heard anything of this...)
Personally, I like the tack welding idea. Now, if I can just find someone in the area who will do the welds for us (we don't have any welding ability/knowledge...)
BEN
:) Hodge,
I'm a little confused with what you're doing with the trannies... As I understand it you're doing the following:
- Using the replacement carrier plates, but discarding the pins
- Drilling New Holes for new dowel pins
- Rebuilding this modified carrier plate with new pins?
Is this correct? Also, you said that there is a possibility that Banebots is shipping out ANOTHER revision to this carrier plate? (I haven't heard anything of this...)
Personally, I like the tack welding idea. Now, if I can just find someone in the area who will do the welds for us (we don't have any welding ability/knowledge...)
BEN:)
Hi Ben,
We are modifying the new hardened plates with 4mm holes drilled and reamed in between the existing holes for the pins. We can't use the original pins as they are in the robot presently, so we got new pins at Atlantic Fastener ($0.31 cents each),but they have to be shortened 1 mm. As Banebots discussed with me, the holes are tapered from laser cutting, and the finish reamer didn't get to some of the surface. therefore, only an edge of the hole is holding the pin. Because of this "slop", I'm afraid welding will take the pin out of square with the plate, and Loctite doen't fill voids. Last time I tried to use the TIUG welder in school, it didn't work well at all. I could try welding your pins with MIG. If you made a collar longer than the pin, and a clamp that would allow access to weld, we might keep the pin perpendicular. Want to try?
With respect to the transmissions that will be coming, Banebots tells me they will have a 2nd revision hardened plate in them with properly sized holes. They are also considering putting tie bolts from the mounting plate corners to hold the plates square and tight to the tranny housing. The 8 screws don't presently do a good job of this.They cannot offer just the revised plates, as the manufacturer will not provide them. Looks like you will have to buy the whole transmission assembly to get it. That could change after the season, as time is short, and they are trying to meet the demand for Nationals. Who knows, by next year, they may have square holes and a square end on the output shaft as shown by Joe Johnson in some posted drawings, and make these transmissions the standard. Stick with these guys as they are willing to listen and make changes.
Elgin Clock
07-03-2007, 18:26
Finally got a chance to post a pic of our solution to the Version 2 carrier plates we received at the competitions, but which still gave problems:
http://www.chiefdelphi.com/media/photos/27573?
We welded in the pins on the version 2 replacements in NJ, and it worked like a charm. (for now) - See picture - This picture I uploaded will be only the first of an ongoing series of reports dealing with these I'm sure...
Oh, and Ben, if you need some welding done, let me know and I'll see what my team can do.
I know we have welding capabilities at our HS.
Team 1816's Banebots transmissions failed in Semifinal Match 2-2 at Wisconsin.We were running the kit transmissions with the 2 CIM adapters. When we opened up the transmissions we found that 9 out of the 10 pins in the two plates had fallen out. We were 1-0 in the semis and were looking to win the second match, and going to the finals. Banebots cost us a chance at a regional victory.
Jacob Plicque
11-03-2007, 15:10
Team 86 had its Banebot Transmission to fail during the first match of the finals at the Florida Regional. We were in a pushing match with both 1902 and 179. We have not disassembled the transmission but we suspect the pins came out. As near as I could tell five (5) teams had Banebot failures at the regional. We will update this after the autopsy.:eek: :yikes:
zander_108
11-03-2007, 15:29
Team 86 had its Banebot Transmission to fail during the first match of the finals at the Florida Regional. We were in a pushing match with both 1902 and 179. We have not disassembled the transmission but we suspect the pins came out. As near as I could tell five (5) teams had Banebot failures at the regional. We will update this after the autopsy.:eek: :yikes:
At least you were still able to deploy your ramps, Our transmissions broke as well, and we were not even able to compete against your alliance like we were originally supposed to.
Does anyone know the length of the older pins? I am thinking of buying some spare pins and having them welded into the transmission for the next competition.
Hopefully we will "lose" everything BaneBots in a few weeks. Going through 6 transmissions and losing a regional because of it is no fun.
(We still had fun, even if we didn't get to play in the finals and came in second)
MrForbes
11-03-2007, 17:39
I measured one to be .586" long. that's 14.9mm
here's a lousy pic of an old plate on a new plate, you can see the new plate's pins don't reach the top
Thanks 1212 for the photo op, but I sure wish you had not had so much trouble, it looked really frustrating.
If teams are worried about this, I would just run with the older plates until you fix the new ones. We saw this thread before our regional and decided to switch back in the old plates and hope they held up. They lasted fine through all 11 matches we played, but we hope to have the new ones fixed and switch them back in at the beginning of the Championship.
We ran them using a 2 CIM per side setup, but we have a highly geared robot (12 fps speed on our wheels), so we didn't do a ton of pushing (still, they held up shoving trying to shove 60 and 842 out of the way to score, and they're beefy drive bots).
Gary Bonner
13-03-2007, 23:30
If the pins were full length, might that have kept them from coming out, i.e. there wouldn't be room for them to move?
We lost our pins in one gearbox during our 5th match at UTC today. But, actually, we used the new hardened plates during the BAE NH regional, too. So, a total of around 15 matches to fail. The other 3 haven't gone yet, I brought our new carrier plates to the Machine Shop at UTC today to get welded. There is no welding equipment there, but the guys there offered to bring them back to their shop and give them to us first thing tomorrow morning. So, it looks like pulling all 4 gearboxes in the morning, and hopefully we'll be ready for our first match.
The old carrier plates failed totally after running them for a few hours before we shipped.
Does anyone know if new gearboxes shipped after a certain date have both hardened steel plates, and the correct pins?
:confused:
bhsrobotics1671
17-03-2007, 01:18
1991 -
according to the banebots site they are shipping with the new hardened plates but as of now they are out of stock. I have gotten word that they are trying to fix the pin lengths as well so when are they coming back? i don't know, all i know is that when they do everything should be good.
evanisthat!
17-03-2007, 01:45
We lost our right side in the second semi-final match at UCF. Somehow, 1902 and 179 pulled off a win in a 2 vs 3 match against 233, 180, and their other alliance partner. We were unable to get the new transmission installed before our time ran out and they needed a replacement. It was INCREDIBLY disappointing to open up the transmission and see that the carrier pins had simply fallen out. Such an issue is, I find, unacceptable. We are moving back to the old, softer plates, and welding the drive shaft in so we don't have to worry about these issues. I am disappointed in the continuing lack of consistency and reliability from these transmissions. Oh well, it’s too late now to change it...
X-Istence
17-03-2007, 03:17
As an Ex-FIRSTie who enjoyed watching the Phx regional, I have to say I feel sorry for all the people with trouble. My old team for this exact reason designed their own transmission, and have used that ever since. We don't change them between years so that we can interchange parts with old bots without having to buy spares. Cheap :D.
During a fix-it window, we replaced the short pins in the new plates with longer ones from the older plates, holding them in with Loctite 680. This take only a few minutes and can be done with a hammer and a center punch.
When we arrived at the Chesapeake regional to install these plates in our gearboxes, we found that the new, hardened plates we had installed prior to the previous regional has lost their pins.
We had lost the second round in the semi-finals, fortunately. It would have been really dissapointing if we had won it, and gone on to the finals. Our robot would have been dead on the field.
I strongly recommend that any teams using these gearboxes change these pins.
After getting to the finals at the Chesapeake regional (and losing to a very strong and worthy alliance), we dismantled our gearboxes to see if our long-pin / Loctite 680 fix had worked.
In a word, no.
On one side, 3 pins had worked loose, and on the other , one pin. Certainly this is much better than with the stock hardened plates with short pins, but not up to a full competition series - we only played in 14 matches, whereas one could play in 17.
We plan either to weld the long pins in place or to drill new, undersize holes in the new plates and press fit the old pins into these holes.
We won't know how our plan works out until we have run many matches in Atlanta.
Hope to see you there.
whytheheckme
18-03-2007, 18:58
We lost all of the pins in one box during matches on friday. That night, I had the other spare set of plates that we had welded an ground down. On Saturday morning when I replaced them, the one box had all the pins missing, another had one missing, and a third had 4/5 missing :yikes:
Beware teams.... Beware!
Jacob
I'm not sure that I understood your comment. Did you mean to say that the welded in pins also came out?
Ben Piecuch
18-03-2007, 22:38
We decided to follow Team 237's advice and spot welded the back of the pins to the carrier plate. The welds stuck up a little (maybe a 1/16th of an inch) but it cleared the outer housing, so no grinding was required. When we went to re-assemble the plates, we found that at least one of the pins on each of the carrier had lost its perpendicularity, and kept jamming up the stage. So, we ended up running both gearboxes with only 4 of the 5 planet gears in them.
We ran 10 matches, 4 practice rounds, and about a hour of practice on the practice field -> No Failure! We haven't taken them apart to confirm their health, but I'm fairly confident that they held together without losing any pins. We'll be double-checking for our post-season comps.
Best of luck,
BEN
whytheheckme
18-03-2007, 23:07
I'm not sure that I understood your comment. Did you mean to say that the welded in pins also came out?
I'm sorry. I just re-read my post and realized that it was confusing. Let me re-word that.
We lost all of the pins in one box during matches on friday. That night, I had the other spare set of plates that we had welded and ground down so that they were ready for installation on Saturday morning. On Saturday morning when I opened the gearboxes, the one box had all the pins missing, another had one missing, and a third had 4/5 missing. The fourth was intact :confused:. After replacing the carrier plates with the new welded ones, we have had no problems.
Beware teams.... Beware!
Jacob
Jeff Pahl
20-03-2007, 13:30
:) :)
With respect to the transmissions that will be coming, Banebots tells me they will have a 2nd revision hardened plate in them with properly sized holes. They are also considering putting tie bolts from the mounting plate corners to hold the plates square and tight to the tranny housing. The 8 screws don't presently do a good job of this.They cannot offer just the revised plates, as the manufacturer will not provide them. Looks like you will have to buy the whole transmission assembly to get it. That could change after the season, as time is short, and they are trying to meet the demand for Nationals. Who knows, by next year, they may have square holes and a square end on the output shaft as shown by Joe Johnson in some posted drawings, and make these transmissions the standard. Stick with these guys as they are willing to listen and make changes.
We were having a lot of trouble with all the set screws in the housings coming loose every time we drove. We took some 1/2" thick bar stock and used it to tie the two black square plates on the transmission together. After that we never had a loose screw (13 matches plus practice time). The transmissions were mounted to a piece of plate that the shaft passed thru. I don't have any pictures right now, if anyone wants to see one let me know and I'll take some tomorrow when we uncrate the robot.
edthegeek
20-03-2007, 19:49
1351 lost the carrier pins on both our transmissions during our second match of the seeding rounds at SVR. When we first heard of the initial problems with the carrier plates, we had our machinist reverse-engineer the original plates and had them made out of higher-strength steel. This gave us the correct tolerances and the correct length pins. We had the new plates by then so we flipped them out in about half an hour. It cost us that match and the next one (we had to queue about 3 minutes after the match in which they failed). I have yet to open up the gearboxes and see how they are standing up, but they did not fail for the rest of the matches.
DonRotolo
20-03-2007, 21:47
Does anyone think that instead of welding, a good hit with a center punch in the pin end flush with the carrier plate will tend to swage the pin in place?
Don
: The thought is that you support the far (sticking-out-and-holding-the-gears) end and give it a healthy whack. The pin shouldn't move, but the end of the pin should expand slightly by the displacement of metal from the ding in the end of the pin. BUT one must consider how hard the material is (can it deform elasically enough to increase in size) and whether the carrier plate will 'grip' a pin enough using this method.
Richard Wallace
20-03-2007, 21:55
Does anyone think that instead of welding, a good hit with a center punch in the pin end flush with the carrier plate will tend to swage the pin in place?Dunno. A light tap with a punch is how I got a pin to pop right out, though. (Actually I tried this after Mark Koors told me about it, just to see for myself how light a tap would do it.)
As I mentioned in a previous post, we found that bonding the pins in place with Loctite 680 did not work as well as we had hoped. Several pins were loose after 18 matches.
I have ordered some Loctite 638, which is apparenty stronger. I'll let you know how this works out. We are setting up a transmission under load and will cycle it back and forth for 20 minutes or so, then check the pins.
We are also getting a few plates welded, and will check these also.
Jacob Plicque
29-03-2007, 16:09
Team 86 had its Banebot Transmission to fail during the first match of the finals at the Florida Regional. We were in a pushing match with both 1902 and 179. We have not disassembled the transmission but we suspect the pins came out. As near as I could tell five (5) teams had Banebot failures at the regional. We will update this after the autopsy.:eek: :yikes:
Our autopsy showed 4 out of 5 pins had fallen out of the final stage and the pin holes were grossly enlarged. Also, the planetary gears for the stage were missing teeth and were unusable. We have bought new carriers from Banebots which they promised will not have this problem with the pins. Time will tell if newer is better. We have 2 spare transmissions and some parts but are nervous about it.
:eek: :yikes: :ahh:
The welded plates did not work out. The heat from the welding warped the plate slightly, and made it unusable.
We will run some tests this week on the Loctite 638 plate.
DonRotolo
29-03-2007, 21:14
Well, after NJ and Buckeye on the new plates - as received from BaneBots just after ship date - no failures on any of the four transmissions. We'll see what happens at the Championships.
Don
Well, after NJ and Buckeye on the new plates - as received from BaneBots just after ship date - no failures on any of the four transmissions. We'll see what happens at the Championships.
Don
Is this with the center-punch method that you posted earlier? If so, then this is good news for teams without welding capabilities. :)
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