NED HELP ON BUILDING 1 OR 2 SPEED GEARBOX

[team2061]

I NEED HELP ON HOW TO BUILD A VERY EASY SIMPLE AND CHEAP GEARBOX FOR 2 CIM MOTORS. THEY CAN EITHER BE 1 OR 2 SPEED GEARBOXES W/ PNEUMATICS SHIFTER.PLEEEEEEEEEEEAAAAAASEEEEEEEEEE HELP.

[EricH]

Why build when you can buy? http://www.andymark.biz/ has gearboxes. Maybe you can get plans from them, or just the gears and make your own box.

Build a cheap gearbox--ouch. You'd need at least a manual mill. Then the material for the sideplates and axles. Then the gears and output sprocket. Assuming you have the mill, you'd be looking at at least a couple hundred, I think. That's about what an AM gearbox costs.

[lukevanoort]

Yeah, AndyMark is going to be nearly impossible to beat, price wise. You may be able to build a two speed crash shifter for less than $300, but it'd be pretty close. A single speed could also be built for around $70, which is only like $20 dollars less than an AM single speed. In both cases, you'd be spending a significant amount of time doing the machining and you would have to live with the possibility that the transmission not work properly.

[team2061]

Originally Posted by EricH

Why build when you can buy? http://www.andymark.biz/ has gearboxes. Maybe you can get plans from them, or just the gears and make your own box.

Build a cheap gearbox--ouch. You'd need at least a manual mill. Then the material for the sideplates and axles. Then the gears and output sprocket. Assuming you have the mill, you'd be looking at at least a couple hundred, I think. That's about what an AM gearbox costs.

MY TEAM WOULD LIKE TO BUILD SOMETHING LIKE THIS BUT DONT KNOW HOW?? DO YOU KNOW WHAT THE ORANGE THINGS ARE THAT ARE CONNECTED TO THE CIM MOTORS? WHAT IS THE THING IN THE MIDDLE BETWEEN THE TWO CIM MOTORS?
http://www.chiefdelphi.com/media/img...478aa6d3_l.jpg

[lukevanoort]

The orange things are some sort of shaft coupling, and the black thing is probably an optical encoder

[EricH]

That particular gearbox seems to be a means of connecting two CIMs to the same planetary gear. Not sure which team built it, but they could probably give you an estimate of cost.

P.S. Could you turn caps lock off? Having it on makes it sound like we're being shouted at.

[team2061]

Originally Posted by EricH

That particular gearbox seems to be a means of connecting two CIMs to the same planetary gear. Not sure which team built it, but they could probably give you an estimate of cost.

P.S. Could you turn caps lock off? Having it on makes it sound like we're being shouted at.

im soory i guess i got used to typing in caps lock, but i no longer will.=)

[team2061]

Originally Posted by lukevanoort

The orange things are some sort of shaft coupling, and the black thing is probably an optical encoder

im sorry you guys but im very new to this. what is a shaft coupling and an optical encoder??

[lukevanoort]

Originally Posted by EricH

That particular gearbox seems to be a means of connecting two CIMs to the same planetary gear. Not sure which team built it, but they could probably give you an estimate of cost.

I don't think that that is a planetary, it looks just like a very large one-stage spur gear reduction.

Originally Posted by team2061

im sorry you guys but im very new to this. what is a shaft coupling and an optical encoder??

A shaft coupling is something that attaches to two shafts and locks them together so that torque can be transferred from one to the other.

At its most literal meaning, an optical encoder is something that uses light to 'encode' something into a form readable by a computer. In this case, it takes rotation on its shaft and outputs a pulse of electricity every time the encoder shaft moves a certain number of degrees. To find out more about encoders, read this.

[EricH]

Originally Posted by lukevanoort

I don't think that that is a planetary, it looks just like a very large one-stage spur gear reduction.

I'd say planetary because it'd be pretty hard to get the reduction from a CIM in ONE stage by means of a spur gear.

One thing that could make life easier is a link to the picture in CD-Media, not just the picture alone. (Couldn't find it by searching; trying again now.)

[Cory]

Those orange pieces are Lovejoy shaft couplings. They can be found here

I used these pretty extensively when I was on 100. They are very nice as far as shaft couplings go. They have a flexible rubber "spider" that sits between the two coupling pieces that allows slight misalignment of the two shafts. They worked extremely well in my experience. The only downside is that they are HEAVY. If you use anymore than a few, the weight will add up very quickly.

[gburlison]

Originally Posted by EricH

I'd say planetary because it'd be pretty hard to get the reduction from a CIM in ONE stage by means of a spur gear.

This gearbox has a 16 to 1 ratio using 5 tooth stem pinion gears on the CIMs and a 80 tooth spur gear on the output shaft. The use of a stem pinion gear requires a coupler since it is too small to fit on a CIM shaft.

[EricH]

Originally Posted by gburlison

This gearbox has a 16 to 1 ratio using 5 tooth stem pinion gears on the CIMs and a 80 tooth spur gear on the output shaft. The use of a stem pinion gear requires a coupler since it is too small to fit on a CIM shaft.

Makes more sense. Is that one of yours, or did you just analyze it to death?

Edit: Yes, it is 662's 2007 robot. The discussion and original picture are here.
Edit2: Did you guys run into any issues? How much did it cost? What other info would help this team?

[gburlison]

Originally Posted by EricH

Makes more sense. Is that one of yours, or did you just analyze it to death?

Edit: Yes, it is 662's 2007 robot. The discussion and original picture are here.
Edit2: Did you guys run into any issues? How much did it cost? What other info would help this team?

Team2061 sent me a PM and I provided him more details, but the short answer is that it cost about $100. It is a simple one stage gearbox using the smallest stem pinions we could find (5 tooth) and the biggest spur gear practical (80 tooth). There is one main issue with this gearbox and that is alignment. The output shaft is supported in three bearings, so misalignment can cause binding. The first year we built this design, we used solid couplers on the CIMs and this also suffered from misalignment and binding. The Lovejoy Couplers took care of any possible binding of the stem pinion gears. Just for reference, this is our first Gen of this Gearbox. http://www.chiefdelphi.com/media/photos/19829

[Tom Bottiglieri]

My recommendation would be to purchase one of the previously stated boxes. Take it apart, study it, and learn how everything works. Take what you've learned, let it ferment for a few months, then put that knowledge to good use next season designing your own.