Tormenta 2 - Build Diary

[Liftoff]

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]

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]

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]

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]

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]

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

[Ellis]

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]

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:
Vid 2:

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]

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]

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.