pic: Team 4499's off season gearbox

[Michael 4499]

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EDIT: It will go 16ft/s not ft/min and this is with a 6" wheel.

[Owen Busler]

16 ft/min? Did you mean 16 ft/sec? If so with what wheel size?

[TheBoulderite]

Wow! That's awesome! Good luck this season, guys!

[Michael 4499]

Originally Posted by Owen Busler

16 ft/min? Did you mean 16 ft/sec? If so with what wheel size?

Yes, I messed that up and it is with a 6" wheel.

[ns3517]

Very nice, this gearbox looks like a solid build. Hope to see it on a robot sometime.

[Lil' Lavery]

Can you explain a little more about what is going on with that top shaft? Why do you have it passing through three bearings? I feel like that is inviting the potential for both misalignment and over constraint. The shaft is short enough that hopefully it wouldn't be a real detriment, but it's also not very useful.

It's hard to see, but does the bottom shaft also have the same issue?

Finally, you may want to consider countersinking those exterior bolt heads in order to allow you to place your wheel slightly closer to your drive rail.

[Chris is me]

I would remove the middle bearing for the top shaft. It basically doesn't add any support and just lowers efficiency / causes potential misalignment for no real benefit. Otherwise, seems good.

[Michael 4499]

Originally Posted by Lil' Lavery

Can you explain a little more about what is going on with that top shaft? Why do you have it passing through three bearings? I feel like that is inviting the potential for both misalignment and over constraint. The shaft is short enough that hopefully it wouldn't be a real detriment, but it's also not very useful.

It's hard to see, but does the bottom shaft also have the same issue?

Finally, you may want to consider countersinking those exterior bolt heads in order to allow you to place your wheel slightly closer to your drive rail.

The top shaft was an interesting one to constrain. Currently, the reasoning for the middle constraint is because there is an e-clip on the other side of the bearing. This is because we are planning on mounting an encoder on the other end of the shaft. If you have any other ways to eliminate that middle support we are welcome to new ideas.

The bottom shaft is actually 2 separate shafts where one ends in the plate just before the tube and the other one starts in the plate inside the tube.

I completely agree with your last suggestion, we are working on it.

Thanks for the response!

[GeeTwo]

Originally Posted by Michael 4499

Currently, the reasoning for the middle constraint is because there is an e-clip on the other side of the bearing.

Do I correctly understand that you are transmitting torque through an e-clip groove? If so, that's going to be a weak spot in your drive train. Putting an e-clip between the load-bearing gears and the future encoder should be OK, and between the gears and the end bearings would not be as good as the outside, but much better than between the gears transmitting torque to/from the shaft.

[Chris is me]

Originally Posted by Michael 4499

The top shaft was an interesting one to constrain. Currently, the reasoning for the middle constraint is because there is an e-clip on the other side of the bearing. This is because we are planning on mounting an encoder on the other end of the shaft. If you have any other ways to eliminate that middle support we are welcome to new ideas.

The bottom shaft is actually 2 separate shafts where one ends in the plate just before the tube and the other one starts in the plate inside the tube.

I completely agree with your last suggestion, we are working on it.

Thanks for the response!

Putting an E-clip between loads on a shaft is often a dangerous idea. It weakens the shaft substantially when something like a spacer could do the same job. I would just use a spacer between the two gears (that goes through where the bearing is currently located) and then put your encoder on one of the outer ends of that shaft.

[Ty Tremblay]

I personally think 16ft/s single speed with 4-cims on 6" wheels is a bit fast. If you find that out too, are you able to increase your final reduction? VEXpro's 82-tooth gear spacing is nice since it allows for a lot of various reductions with the gears they have in stock.

[Michael 4499]

Originally Posted by GeeTwo

Do I correctly understand that you are transmitting torque through an e-clip groove? If so, that's going to be a weak spot in your drive train. Putting an e-clip between the load-bearing gears and the future encoder should be OK, and between the gears and the end bearings would not be as good as the outside, but much better than between the gears transmitting torque to/from the shaft.

Great idea, I think I can see a few changes that we can make to the gearbox to incorporate this.

Originally Posted by Chris is me

Putting an E-clip between loads on a shaft is often a dangerous idea. It weakens the shaft substantially when something like a spacer could do the same job. I would just use a spacer between the two gears (that goes through where the bearing is currently located) and then put your encoder on one of the outer ends of that shaft.

Thanks for the suggestion, we will look into implementing it.

[Michael 4499]

Originally Posted by Ty Tremblay

I personally think 16ft/s single speed with 4-cims on 6" wheels is a bit fast. If you find that out too, are you able to increase your final reduction? VEXpro's 82-tooth gear spacing is nice since it allows for a lot of various reductions with the gears they have in stock.

Yes, we are able to make our own gears and change them out, we are using a 72 tooth spacing. We were just planning on making a fast drive base while learning the basics of gearbox manufacturing.