19-05-2015 15:11

cbale2000

Re: pic: Team 3940 CyberTooth 2015 Drivetrain

How are the gears kept on the bearings?

We use a very similar style of geardrive but we put bearings on the axles of the idler gears and use a hex shaft with snap ring groves to hold the gears in place.

19-05-2015 15:12

BrendanB

Re: pic: Team 3940 CyberTooth 2015 Drivetrain

The visual properties on the CIMs aren't the same. Try again.

On a more serious note, beautiful machine this year that gear drive is slick!

19-05-2015 15:43

Nick Lawrence

Re: pic: Team 3940 CyberTooth 2015 Drivetrain

The bore in all of the gears is sized for a tight press-fit. It worked great for us.

Thanks! We're a little obsessive about overall machine aesthetic and team imagery.

-Nick

19-05-2015 16:03

Jay O'Donnell

Re: pic: Team 3940 CyberTooth 2015 Drivetrain

What was the reasoning behind the gear drive over something easier to implement? It's really cool looking, but was there a reason regarding function that you went this way?

19-05-2015 16:35

Nick Lawrence

Re: pic: Team 3940 CyberTooth 2015 Drivetrain

Our original chassis requirements included a few distinct constraints:

- We wanted the chassis to have a 28" x 32" footprint in 'long' orientation
- We wanted the front of the chassis to have an opening large enough for both totes and recycling containers.
- We wanted to have a reliable H drive
- We wanted to use the new AndyMark DuraOmni Wheel
- We wanted to have a raised center wheel to cross the scoring platforms.
- We did not want to spend a lot of time assembling/disassembling the robot for Transportation Configuration requirements.

Furthermore, we did not want to pursue serpentine chain or belt options as we were far less experienced with these ideas as a team, and we were concerned about the reliability of these methods. Gears ended up allowing us to make the drive modules much narrower, allowing for this opening in the front of the chassis to be large enough for our initial constraints. We also really loved how a drivetrain like this is virtually maintenance free with periodic lubrication.

-Nick

20-05-2015 08:52

roboryan

Re: pic: Team 3940 CyberTooth 2015 Drivetrain

Looks awesome! Being my team is trying to focus on aesthetic and got our first ever custom sheetmetal chassis this year. I was wondering what thickness of sheetmetal are you guys using? We went with 1/8" but we think it might be alittle thick for our purposes but we aren't quite sure.

20-05-2015 09:50

Nick Lawrence

Re: pic: Team 3940 CyberTooth 2015 Drivetrain

Thanks! This chassis uses 1/8" 5052 AL. With a rigid one-piece bumper frame like Team 33, you can get away with a lot thinner. 1/8 does give you plenty of piece of mind when using AL sheet, as long as it is is adequately lightened.

-Nick

20-05-2015 10:16

MoistRobot

Re: pic: Team 3940 CyberTooth 2015 Drivetrain

Nice. How do you keep the center "H" drive from lifting the robot?

20-05-2015 11:40

Nick Lawrence

Re: pic: Team 3940 CyberTooth 2015 Drivetrain

The strafe module assembly doesn't produce enough torque to lift the robot when run with MiniCIMs. Two CIMs got pretty close to lifting the chassis, but even then it wasn't a problem.

- Nick

22-05-2015 19:43

asid61

Re: pic: Team 3940 CyberTooth 2015 Drivetrain

Does the center HiGrip wheel cause scrubbing when translating left or right?

22-05-2015 20:20

tim-tim

Re: pic: Team 3940 CyberTooth 2015 Drivetrain

My interpretation is that the center HiGrip wheel only contacts the scoring platform, never the carpet.