Gear ratio for a long hard pull

frizzen · #1 03-31-2006, 03:02 AM

Alright, I'll let everybody in on a part of a 'black project' of mine, but only because I want to double check some math. I'm using a modified Friction motor for a gearbox. (Project spoiler: it's gonna be part of a heavily modified 3 channel RF+IR ZZ-M setup.) Once I've got proof of concept and it works well enough, I'll be doing a tutorial.

*PLEASE* check my math. The goal is torque, I need every bit of torque I can get. At the very least, I want enough torque to be able to do a dead pull on a roughly 70 gram rolling item.

Going to be adding on a:
6 T motor pinion
maybe 22 T axle gear

--- Gearbox currently
10 T (former axle, now gearbox input)
22 T / 10 T idler
24 T / 10 T idler
42 T / (former spring housing, now winch drum)

Which should make the Gearbox alone a 22.176:1 ratio.

If I add the 6 T motor pinion directly to the 10 T gearbox input, that should bump the final drive to a 36.812:1 ratio.

The 6 T motor pinion meshing with the 22 T axle should give me a 3.667:1 ratio. The 22 T and the 10 T input would make a 0.454:1 ratio, and bring my final drive back to 36.9598:1 ratio. Which adds more friction and not much help to the ratio without the 22T idler.

If I do some cut and graft of the previously mentioned 22 T axle gear idler onto the same shaft as the 10T gearbox input, that should give me something like an 81.164:1 ratio. (not sure if possible though)

The motor I've got for this is smaller than the Bit motors, it's got that lovely 3-wire setup, so I'm not sure how much more work would be involved to switch it to like a ZZ or ZZ-M motor.

frizzen · #2 03-31-2006, 04:40 AM

Damn the torpedoes, full speed ahead! (but I still want somebody to double check that math)

Looking at the gearbox's reduction number of a whopping 22.176:1 I knew I needed more reduction, so I went ahead and mounted the 22 T idler onto the 10 T gearbox input shaft. Not the easiest, and needed a little more hacking than I'd intened to do, but it fit!

So then to make sure my winch actually works, I pulled the idler and axle gear off a ZZ-M with green motor and 7 T pinion, meshed that with my new gearbox input gear (the 22 T, so the overall ratio at the moment is around 69:1) stuck a weight on my temporary winch line, and ran it in and out to make sure I wouldn't have kink problems. Nice. That worked, so I hooked up to a Charg-N-Go truck clone, and dragged it across my keyboard. Sweet. So I hooked it up to another ZZ-M, and I dragged that across my keyboard. So far so good! Since it still didn't fail, I put the ZZ-M on the desk next to keyboard with 1 axle resting on edge of the board, the winching truck on opposite side of keyboard, dragged it up and across!!! Hell yeah, the winch does work!

So, next because I know that tiny motor won't have nearly the torque of the ZZ-M motors, I figured I should check to see if the gearbox can do a dead line pull without the help of any motor being meshed in. So I raised the gearbox until I had the monster airborn, and the gearing is low enough it didn't wind out my cable. To make sure it wasn't stuck, I started spinning the input gear, and the Truck-On-A-Rope would slowly raise and lower. Rock and roll!!!
-
From this, I now know that:
1, this will work.
2, seeing this in operation is gonna be even cooler than the winch on Desperado.
3, even if the IR Rod's motor is absurdly gutless it will still let me vary the length of line, even if it can't do a true winching on a ZZ-M.
4, I need to hurry up and get the TX part finished so I can test the RX.
5, this is gonna be so wicked, and I've gotta decide if I want "Warn" or "Superwinch" decals for the body.
6, I should probably go to bed

frizzen · #3 04-07-2006, 07:44 AM

Ok, here's a teaser. Will someone check my math NOW?

frizzen · #4 06-24-2006, 01:48 AM

Teaser.

Anybody want to check my math now?

Azimov · #5 06-24-2006, 04:31 PM

This is pretty cool and I'm glad you bumped it. I have my own ideas tumbling around in my head ATM and find this inspiring. The use of the pen car circuit is pure genious. I could kick myself for destroying mine over a year ago for parts.
I'm no gear ratio expert, but from what I can gather from your text, your final configuration is 69:1. That's a good healthy bit of torque there. If it's lifting the weight you're looking for in a reasonable amount of time, then I'd say you've got it licked.
I know you want an accurate number so you aren't making any missteps in your future tutorial, and honestly, I'd like chilli or someone to confirm your findings so that a range can be found that will easily lift an MT without taking an hour to do it.
But, from what I get from your project at this point, 70:1 is a good scale ratio. I'd say anything between 60-100:1 should work very well.
EDIT: A motorworks motor should switch out with that pen car motor. It has the three wire connection as well.

frizzen · #6 06-24-2006, 09:15 PM

Nice that it finally got noticed.

Once I'd already hacked up my IR Rod racer, I found one of those pen cars. It has a switch and PCB layout that are a LOT better for this application. The pen racer was like 12, and the IR Rod is currently on clearance at RS.

Here are the new body guts.

Playing with it some yesterday, I realized that part of the ZZ-m board had popped. (an inductor in the reciever circuitry) So now I'm eyeing little cars with bad intentions... (StuntCars and MuscleMachines are supposed to have dual h-bridge boards)

Namuna · #7 06-24-2006, 11:31 PM

frizzen...I WANT some video of that badboy in action!!!

I'm likin where you're going with this project! I'd love to see a tut on it!

Nice work.

frizzen · #8 06-25-2006, 02:33 PM

Well if it makes you feel better, I WANT to get it finished so I can play and get some videos.

The truck is set up with blue gear crawler, long travel front suspension, massively increased steering throws for tighter turning, reversed offset rims, wheel weights, clearanced pcb cover...

The body features a 36159 lighting board (the smallest one), 4 LEDs, an IR Rods single channel board with sensor poked through roof, the roof has top racks, the front has the start of a Hawse Fairlead between bumpershell and grille... Will eventually get a winch drum mounted up front, front and rear recovery points, and stick some offroad junk in the top racks (Gascans, Hi-Lift, pick, shovel...) so my IR recciever isn't lonely.

The transmitter was a 49mhz ZZ-M, it now features a steering wheel button for right/left control, a pair of microswitches in the upper surface that are protected when charge cover is closed, an LED shroud on the left side, and a cut down IR Rods TX circuit board inside
.
I've got to either swap a stock 49 mhz ZZ-M board in, or an inductor off the bad board in my Articulate Beast then give that one a smaller board wo- lighting port. I'm also condering lowering the PBC deeper into the chassis to gain a little more clearance as it's pretty tight with all the junk in the trunk.

Azimov · #9 06-25-2006, 03:40 PM

Just lovely. You are building in all of the features I've been mulling over. I'm still waiting for my Iwaver board, but I'm considering using it for an SE as the hookup is straight forward. Then, sticking the SE board into the MT. Not sure if I'll do this as articulation is a must for me and it's difficult with all those other features. A major chassis design would be in order, and I'm considering that as well.
Great work!

willtobeweird · #10 08-20-2006, 09:58 PM

Too cool im in awe by what some of you guys do.I have so mcuh to learn and this post is very inspiring.Keep up the good work!!

frizzen · #11 08-24-2006, 02:42 AM

Sorry guys, I got sidetracked by the BitPimp Topless Contest, and started building an experimental ZZ-M slipper-clutch rear axle that might unlock even more climbing potential.

- I've dropped the PCB height of this truck several *more* thousandths below stock, so hopefully I'll be able to make the motor able to mesh with the winch input without requiring a "gurney bubble" be added to the stationwagon.
- I think I figured out a way to unlock even *more* steering travel to the side that was slightly lacking.
- The replacement ZZ-M PCB arrived (Many thanks to bitpimp "Clint")

Right now I'm stuck on the pinion to input mesh issue, if the lighting stays with body, then the winch board stays with body, so the winch motor HAS to go with body; So the winch gearbox will have to go with body too. Solves a few issues, but creates others.

Winch 'em if ya got 'em!

frizzen · #12 09-06-2006, 12:55 AM

Edit isn't working... So, it's a new post.

Swapped in the new PCB (Thanks again to Clint, you f**king rock man!) Had a moment of panic when I went to test it though, ALWAYS turn it **ON** before you freak out and recheck all the connections!

Took the old PCB from this project, swapped the bad components off for replacements from my crawlers board (which was bad from RS, never cut a chassis before you make sure it works!), and installed the now fixed board on my crawler.

-
Think I managed to find the graphics I want for the body.

on the hood

running along both sides, near the belt line

A-Tom · #13 09-06-2006, 05:46 PM

Quote:

Originally posted by frizzen
[b]Edit isn't working... So, it's a new post.

Sorry, I cannnot see the picture.
Would you please fix the link?
Thanks

Azimov · #14 09-07-2006, 03:14 PM

Glad to hear things are coming together for you. I like the graphics. Should make for a very cool crawler look.

frizzen · #15 09-08-2006, 07:16 AM

What picture can't you see? The various teasers through out the thread, or the corporate logos I mentioned in the last post (which I have no permission to use or any affiliation with that company)? Either way, they're hosted through either PhotoBucket or BitPimps, the urls are good, so unless my bandwidth limit was exceeded, the problem was not on my end.
--
Right now my big stumbling block is going to be mounting motor to gearbox, and after that it's getting Motor-Gearbox into the body properly. Ugh.

Once that's all fitted, I have to recheck my TX, if the remote works and I wired it up correctly, I'll be in the home stretch! Make the graphics, fog some clearcoat, wrap some embrordery floss onto the drum, make the winch hook, install some recovery points, superficial stuff on the TX, install some scale junk on the toprack, final fitment...

So near, so far.