Tormenta 2 - Build Diary

[Liftoff]

Re: Tormenta 2 - Build Diary

Hmm interesting!! I find it mechanically impossible for this to happen without something breaking :shock:

would you mind posting a couple of pics of the wheels and shaft - you got me really intrigued by this...especially since I had similar problems before, which I solved using this setup.

[Max]

Re: Tormenta 2 - Build Diary

Are you sure the head of the reverse screw is up against the face of the wheel? Sometimes it needs a few washers as there is a limit to how far you can screw in the screw. We have had problems before where we did the bolt up as hard as we could and the wheel would still unscrew, solved it with loctite and a large penny washer.

[Ellis]

Re: Tormenta 2 - Build Diary

I am sure that it is all locked up, yes. More so than with the blue wheels, in fact. We never locked onto the wheel with those, but onto the face of the nut insert. We used washers (2) like this for the blue wheels, but they get seriously deformed and eventually are no good. We moved to just using m6 nuts, which work much better, but despite all of the friction the wheels still loosen.

I am beginning to think there is not enough friction between the shaft and the wheel, and too much between the wheel and the reverse thread screw. However if it were all locked properly nothing should loosen, so go figure! :P

Going to try loctite now.

Oh and I'll get some pics and video up if we manage to fix this.

[typhoon_driver]

Re: Tormenta 2 - Build Diary

I've had similar issues in the past. What you want to find is some reverse screws with a hex head to really tighten them up proper

[Bodge Job]

Re: Tormenta 2 - Build Diary

its odd that it loosens so quickly? mine takes quiet a few battles to severely loosen, and to prevent this i have hole in the wheel guards so i can tighten the left handed screw. i have no idea why yours loosens so much though, got to be some hidden play somewhere.

[Liftoff]

Re: Tormenta 2 - Build Diary

Is the wheel made from plastic or metal at the part it threads onto the shaft?

[Ellis]

Re: Tormenta 2 - Build Diary

I've had similar issues in the past. What you want to find is some reverse screws with a hex head to really tighten them up proper

We're using the ones sold by RoboChallenge, allen key head, we can put enough twist on them to break them, so we can crank them properly.

Is the wheel made from plastic or metal at the part it threads onto the shaft?

The wheel itself is plastic, like the blue wheels, nylon or similar, but no we have a long 3/8 nut insert onto the shaft.

We have loctited everything and we'll see how it fairs soon.

[Ellis]

Re: Tormenta 2 - Build Diary

The loctite appears to have done the trick, at least for the minute, as the video below shows. Hoping it's a permanent solution, the alternative is to try and be clever with grub screws or something and if that's avoidable, great.

We decided to document the process of making these wheels in the hope that it might help someone...

Vid 1: http://www.youtube.com/watch?v=AcIIUGBJzJM
Vid 2: http://www.youtube.com/watch?v=vqf9i_er56Q

The above probably won't interest many of you, but part 3 has a test drive:

http://www.youtube.com/watch?v=XlddYVSIe7s

(armour is off because we may have further clearance issues, will look into it tomorrow)

Briefly forgetting the wheels and their undoing problem, this + indoor tests have been a pretty good shakedown for the new drive system. I won't say this has been one of the best improvements to the machine until we've stuck it in the arena, but even now I would recommend it to anyone who is overvolting to get some speed. The motors get warm at most, after a drive like the above before the motors would have been toasty.

Also, an added bonus of the wheels, they leave epic skid marks everywhere. (including the kitchen floor)

Thanks for the help.

[Mega Masher]

Re: Tormenta 2 - Build Diary

Thanks for that, i may use that method in the future for my robot.
Good luck with the championships and hope you do well.

[Eventorizon]

Re: Tormenta 2 - Build Diary

Also, an added bonus of the wheels, they leave epic skid marks everywhere. (including the kitchen floor)

As the rubber goes down over the weekend, we will see the cars going faster and faster. Only problem is if it rains the track surface will be come far slicker than it would otherwise.

[Bodge Job]

Re: Tormenta 2 - Build Diary

Awesome, looks good! and a very similar manufacture method to what I would use... and i wouldn't mind wide wheels as wide as the, but I find the blue wheels have brilliant grip when treated and used well.

[Ellis]

Re: Tormenta 2 - Build Diary

I have spent the past 2 days slowly putting this thing back together, analysing it as I go, and had it 95% ready and decided to drive it around a bit. Can't get enough practice and that.

I broke it. D:

Well, the rear right gearbox failed. Completely locked up. Managed to catch it before the motor burned out, so no issue there. The Gimson stuff also appears to be unharmed. It's our old friend the second stage pin that decided to come loose.

I'm a bit disheartened as I had finally got everything bolted back on, and minutes later I had to rip it all apart again, but having opened up the gearbox things could be a lot worse. Only a single pin failed, in the past all of them would fail in unison. And, the gearbox that went is the oldest we own, it's one of the two that Sam gave is at the '12 champs as a sorry for killing our robot (lol). It used to be in NST. I don't even know how long ago NST ran drills, but we have had it for a year (and used it overvolted, a lot) on top of that.

So, as just one pin gave way and it's an ancient gearbox I think we're still safe. It might well have been loose from the start. I have a replacement gearbox to put in. Don't know what we'll do if they continue to break...

--------------

In other news we have made our battery box and have discovered we need an extra tensioner for the chain, which will have to be simple (leave in 3 days). In happy news, the wheels seem to be holding up very nicely.

[Bodge Job]

Re: Tormenta 2 - Build Diary

how many spacers have you got in that gear box? as you've charged the reduction you would need 2 of the metal ones rather than one. as originally they had 2 spacers when they had the plastic first stage reduction, and then if you changed it to metal gears, you probably had to remove them. But when you changed it to 24:1 reduction, the gears are thinner so you need more spacers. The spacers should give the pins less room to fall out.

[Ellis]

Re: Tormenta 2 - Build Diary

You don't need spacers in drill gearboxes, unless I'm not understanding something. If you mean the spacers thing mentioned on the Gimson website, that's unique to GR02s. In fact, you can't have them in drills, as it would force the shaft beyond the circlip and cause the whole system to fail.

Of course, you don't need/can't place spacers in drill gearboxes. The groove cut for the circlip dictates the position of the shaft in and out, so it's fine. The gears tower up to the same height as the factory gears anyway, so we shouldn't have to do anything more advanced than replacing the gears and motor.

[Bodge Job]

Re: Tormenta 2 - Build Diary

What about the metal disks that are between the motor and first set of gears? mine came with two, and as you gearboxes looked identical, I presumed they were the same. I found that the pins came out if I was missing some. I don't know it yours are different though.