1986 Quadzilla Gearbox

[jspatz1]

Four Banebot 550's driving a AM toughbox.

Originally Posted by jspatz1

Four Banebot 550's driving a AM toughbox.

Nice! But what will it be used for? That's a lot of torque, so this makes things really interesting!

[ratdude747]

Originally Posted by SuperNerd256

Nice! But what will it be used for? That's a lot of torque, so this makes things really interesting!

a shooter?

Originally Posted by ratdude747

a shooter?

But why 4 motors? Ours works awesome with only two.

It's like using 4 CIMs for one side of your drive (I wish); There's usually a reason behind doing that instead of the 2 on one side 2 on the other.

Whatever it is, I like it! Please upload a video of it soon if you can!

[CalTran]

Whatever it is you have planned, I can't wait another month to go check it out at Greater Kansas City. I get the feeling this will be another one of those "Did you know Team Titanium has like a half-dozen 2" pneumatic cylinders on their robot?" "They make 2" cylinders?"

Why do I have the feeling that this is somehow related to the use of this gearbox?

[Alpha Beta]

Originally Posted by SuperNerd256

But why 4 motors? Ours works awesome with only two.

2 motors would get the job done. 4 motors were possible, so instead of saying why, we said why not. We still haven't settled on which iteration will make it on the final bot. Added advantages could include saving valuable seconds in autonomous for a shooting wheel to spin up, and the ability to shoot consecutive shots with less recovery time.

With a lathe we were able to pressfit a piece of steel that allowed the 0.125" motor shaft to accept the 14 tooth CIM pinion. This opened up a world of possibilities for 20 dp gearboxes with only minor modifications to the faceplates. Many of the 32 dp gearboxes designed for these motors were/are in short supply.

Free speed of a BB 550 is reported at 19300 RPM. Toughbox as pictured here was the standard 12.75:1 reduction. Lots of other gear ratios are available for the Toughbox if needed. Before breaking in the gearbox it ran the output shaft at 1330 RPM. That is about 87.9% efficiency. Not too shaby for our first ever modification of a gearbox.

PS. It is not all that quiet. We're also considering how much power it would take to make a minimal robot fly. Some year that's got to come in handy.

[Hawiian Cadder]

That looks awesome. Keep in mind that if you are running all 4 motors off a single battery It may create a voltage drop and causing inaccuracy your efficiency calculation, you could use a multimeter to find the actual voltage and then use the RPM/Volt given for the motor to calculate what the free speed in that scenario would be, and calculate a more accurate and probably better efficiency, even if the voltage were only a few tenths of a volt below 12 it could push your efficiency up a couple percent when taken into consideration.

[PAR_WIG1350]

You would be better off if you could reduce your moments of inertia by an order of magnitude or so. Those are some big gears you're using.

[Aren Siekmeier]

Originally Posted by Alpha Beta

2 motors would get the job done. 4 motors were possible, so instead of saying why, we said why not.

Precisely. We are going with a 4 motor shooter gearbox, for which the parts will be rolling in this week. We managed it with some stock gears, shafts, and bearings and some custom plates we're sending to a local machine shop. They're nothing we couldn't have made ourselves, but frankly its a lot easier and less time consuming on a CNC machine.

4 motors means you can make the key shot you were making with two motors with a much bigger margin for closed loop speed control, meaning the wheel will remain consistent in the long term with battery voltage fluctuations, and potentially in the short term in the time frame of each shot (if the control loop can respond fast enough). Also, now you have the motor power to chuck the ball full court if you ever want to (and get 3 points, of course )

[Aren Siekmeier]

Originally Posted by PAR_WIG1350

You would be better off if you could reduce your moments of inertia by an order of magnitude or so. Those are some big gears you're using.

This effect may be desirable if they are using it to power a shooter wheel.