pic: Chain and Wheel in Tube

[Al Skierkiewicz]

Matt,
Having worked through a problem with this design with a team at Championship a few years ago (it did not go well), I can only give you a few words of caution. It is essential that you provide for chain stretch. Chain stretches and it only takes a small amount to jump up during operation and lock the drive against the inside of the tube.
The second is a restating a post I made just a few weeks ago. If you want to win on Einstein, don't design something that can't be fixed in a few minutes with simple tools in near dark conditions.
Good Luck!

[notmattlythgoe]

Originally Posted by Al Skierkiewicz

Matt,
Having worked through a problem with this design with a team at Championship a few years ago (it did not go well), I can only give you a few words of caution. It is essential that you provide for chain stretch. Chain stretches and it only takes a small amount to jump up during operation and lock the drive against the inside of the tube.
The second is a restating a post I made just a few weeks ago. If you want to win on Einstein, don't design something that can't be fixed in a few minutes with simple tools in near dark conditions.
Good Luck!

This is exactly one of the reasons that we won't be switching from our WCD chassis to this.

[Nate Laverdure]

Originally Posted by MichaelBick

dead axles

Originally Posted by EricH

Bolt sprocket to wheel

Originally Posted by GeeTwo

dead axle

I encourage those advocating for dead axles to play with this design and see if you can make it work. Matt has already posted the CAD for you to work from.

In FRC context, dead axle design involves transmitting torque directly from the sprocket to the wheel, without passing any torque to the axle. In this case, you would need to package both a bearing and a torque transmission feature into the 16t (or 17t) sprocket. I'm just not sure it's possible to package all that in such a small space.

BEARING
To save space, I would probably want to bore the sprocket to fit a needle roller bearing. In a high-risk application like a drivetrain, I wouldn't want to have needle roller bearings running on anything but precision ground steel shafting, which means that I can't use a bolt as the dead axle. In doing this, I have modified the 16t sprocket out of its COTS condition; this is a big deal for 2363 for various reasons.

TORQUE TRANSMISSION FEATURE
Maybe some custom bolt pattern will do this? You can't fit the 1.875" BC here. I don't think you can fit any part of the versakey system here. In making this torque transmission feature, I have probably created a custom wheel hub and may have even modified the wheel out of its COTS condition.

On top of all this, joining the sprockets to the wheels will require a bigger pocket in one of the walls of the tube, weakening the structure further.

TLDR: The precision machining requirements for this live axle design are WAY lighter than any comparable dead axle design that I can think of.