Thread: pic: FRC294 Prototype base
View Single Post
  #1   Spotlight this post!  
Unread 31-08-2007, 21:16
Alan Ing Alan Ing is offline
Registered User
None #0368 (Kika Mana)
Team Role: Mentor
  
Join Date: Oct 2001
Location: Honolulu, Hawaii
Posts: 76
Alan Ing has a reputation beyond reputeAlan Ing has a reputation beyond reputeAlan Ing has a reputation beyond reputeAlan Ing has a reputation beyond reputeAlan Ing has a reputation beyond reputeAlan Ing has a reputation beyond reputeAlan Ing has a reputation beyond reputeAlan Ing has a reputation beyond reputeAlan Ing has a reputation beyond reputeAlan Ing has a reputation beyond reputeAlan Ing has a reputation beyond repute
Re: pic: FRC294 Prototype base
Have you used Team 33's design before?

In 2005 we used a modified Team 33 style 4 speed transmission. Aluminum side plates instead of Delrin and oilite bearings for the sliding members. We also used 2 CIM motors per transmission through some custom gearing and added additional reduction for a top speed of around 12 - 13 FPS in high. The transmission shifted perfectly every time and it was really neat to hear it constantly shift. It served us very well that year but we did have a problem with it. The shifting gears were prone to heavy wear on our machine. All of the hard shifting caused the teeth of the gears to elongate and become pointed as well as show extra signs of wear where the gears jam into each other during each shift. At Las Vegas, I showed a set to Andy Baker, and he mentioned that everything looked like it was constructed right (proper welds and all, but that he had not seen this problem before). We ran through 5 sets of cluster gears before the season ended (2 regionals and championships).

Now I can't say that this will happen to your team since we did modify the design, but we finally resorted to case hardening all the gears with Kasenit and a small furnace before we got acceptable wear resistance.

Should you also have this problem, consider case hardening the gears. We still use the robot for demos and the gears look fine.

As a suggestion, if you automate the gearbox, consider locking out 2nd gear. With 4 CIMS, the robot stays in 2nd for only a fraction of a second and almost immediately shifts into 3rd. We played with all sorts of rpm shift points, but eventually we just locked out 2nd making it a 3 speed and the robot worked much more smoothly. Of course we could manually put it into 2nd if we wanted to.

The Team 33 design served us very well in 2005 and is about the coolest to hear operate. Were glad we made it, but frankly we don't use that design anymore since it is much easier to buy AndyMarks solution and modify them for our use.

Anyway, I thought I'd share our experiece with the 4 speed design in case you haven't tried it before.
Reply With Quote