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View Full Version : Planetary gears, aother idea...



yoshi
08-23-2006, 07:56 PM
k, so i'm running some ideas through my head again about a reverse box and or a jackshaft design and I was wondering, why not put a planetary on the output shaft going back to a second planetary attached to the main center drive shaft. One chain, maybe 2 for strenght, no big sprocket and you should be able to get the gear ratio you want fairly easy. It would also be pretty simple to get a reverse off one of the planetary systems and you can have high low gear, actually, I think you could have 2 high and 2 low gears, wait, you can reverse it as well so I think you can have 3 highs and 3 lows plus reverse? It's getting a bit confusing but I figured i'd jot down a basic idea of what's going through my head and let someone a little smarter figure out the details. I think you can get like a 3.4:1 ratio from a planetary and if you add the 2 together that's a max of like 6.8:1 ratio if your supose to add the ratios together, but I don't know. I get really confused on figuring out actual ratios.....

hero_saku39
08-23-2006, 08:22 PM
:shock: :? can you draw a picture :D

yoshi
08-23-2006, 08:47 PM
:shock: :? can you draw a picture :D
Just imagine a planetary gear attached to the output shaft of a normal, front facing motor with a chain going back to another planetary that has a cv or u-joint on either side. The ratio's are the technical part but the basic deal is 2 planetars connected by a chain to get the gear ratios down....

bdkw1
08-23-2006, 09:03 PM
Double stack 3.4 planetarys will give you 11.56-1 .

Stick with the one planetary and use a strait gear drive like hornet has.

High + low + reverse with the CV's about .5" apart. Way cool.

K-fab
08-23-2006, 09:18 PM
Okay, I've read this thread four times now and the only thing I get is that I'm completely and totally confused! :?

Since I know squat about diffs, someone want to splain me what a planetary setup is?? :(

KWiKSand
08-23-2006, 09:40 PM
Click on the animation thing about half way down the page

http://auto.howstuffworks.com/automatic ... ission.htm (http://auto.howstuffworks.com/automatic-transmission.htm)

This is basically what a Jeffco has to be. It is standard Automatic Tranny stuff.

bdkw1
08-23-2006, 11:30 PM
A lot of drag tranny's are planatary units. Lenco, Liberty,Jeffco...... Just 1 planatary cluster per gear manually shifted. They get more gears by stacking them together.

http://www.lencoracing.com/racetr%7E1.htm

yoshi
08-24-2006, 06:00 AM
The reason i'm wanting 2 planetarys is the reatio. Jeffco has a faily decent size sprocket attached to his upper input shaft. I want 2 smaller planetarys (instead of 1 planetary and a bigger sprocket) so I can mount the cv's or u-joint at the bottom of the frame instead of having it higher for sprocket clearance.....I

hotwheels000
08-24-2006, 02:46 PM
are you planning on turning the jeffco side ways (flat). otherwise i dont follow why the sprocket size on his unit would be an issue.

yoshi
08-24-2006, 04:22 PM
are you planning on turning the jeffco side ways (flat). otherwise i dont follow why the sprocket size on his unit would be an issue.Not gonna use the Jeffco unit at all in this idea, just using the size of the sprocket as a refrence saying it wouldn't be needed. Just 2 planetaries with smaller sprockets on them, maybe a 4 inch sprocket in the back so the cv is the lowest part. If you have a big sprocket, the sprocket is at the bottom of the frame so it's protected which raises the cv up...

Bugpac
08-24-2006, 05:31 PM
hmmmm, wouldnt the planetary gears get rid of the sproket all together, what is the point to have planetarys, and a sprockett,at bottom, kind of defeats the purpose doesnt it? 8)

yoshi
08-24-2006, 05:46 PM
hmmmm, wouldnt the planetary gears get rid of the sproket all together, what is the point to have planetarys, and a sprockett,at bottom, kind of defeats the purpose doesnt it? 8)how are you gonna connect the front planetary off the motor to the planetary with the cv's about a foot back?

Bugpac
08-24-2006, 06:12 PM
hmmm, seems like building a jeffco or hornet type gear box be way more efficent, didnt relize the theroy u have is to hang planetarys in mid air for gear reduction...

yoshi
08-24-2006, 09:51 PM
hmmm, seems like building a jeffco or hornet type gear box be way more efficent, didnt relize the theroy u have is to hang planetarys in mid air for gear reduction...Yerp, gonna bolt the rear body to the frame in the back but the front would be on bearings so you could incorperate reverse outta it since the body has to spin to get the reverse to work....

Bugpac
08-24-2006, 11:02 PM
hmmm with your machine guy prices, you probbally can buy 10 or 15 jeffcos for what he is gonna charge... 8)

yoshi
08-25-2006, 06:11 AM
hmmm with your machine guy prices, you probbally can buy 10 or 15 jeffcos for what he is gonna charge... 8)Jeffco unit is $3,600.00. I'm talking about using 2 off the shelf planetarys, making a bracket to bolt one to the motor, and a couple brackets for sprockets and flanges....


I just had an idea, not saying i'm gonna start doing this....

masterfabr
08-25-2006, 07:28 AM
YOSHI,IT'S A HELL OF A LOT EASIER SAID THAN DONE! Believe me.

Bugpac
08-25-2006, 07:37 AM
hmmm with your machine guy prices, you probbally can buy 10 or 15 jeffcos for what he is gonna charge... 8)Jeffco unit is $3,600.00. I'm talking about using 2 off the shelf planetarys, making a bracket to bolt one to the motor, and a couple brackets for sprockets and flanges....


I just had an idea, not saying i'm gonna start doing this....


lol, i gues im just not understand how you would do the planetary attachment...

yoshi
08-25-2006, 08:42 AM
Since the idea is in my head, it may not work and may cost more than I think. I can see it pretty good as a thought though... :roll:

JJ450S
08-28-2006, 11:40 AM
Hi Guys,
I have been watching the forum the last couple of weeks, lots of good information. I have been considering building something like a short sand car for quite some time now only school takes priority. Just signed up today and had to get in on this thread.
Yoshi, I am experienced with planetary sets, I am on the OSU Mini Baja team and I designed and built the transmission last year, that transmission took us to the top ten finishers of 168 cars at competition. First thing is, there is no such thing as an off-the-shelf planetary set; the ones that are off-the-shelf are not near tough enough, you know it is undersized when its torque specs are in inch-pounds. The transmission I designed used a planetary set as the primary reduction then a silent chain for the final reduction, it even has an oil pump. The planetary set was highly modified from a Toyota automatic transmission. Another thing, good luck finding a ratio greater than about 3.5:1. You are correct in that they offer a ratio, direct, and reverse all in one package, just in order to get reverse you have to have a ring gear break band, for direct you have to have a movable (preferrably syncronized) gear and shift mechanism. It most definately is attainable if you want to put fourth the time and effort and makes for one smooth tranny. If I can figure out how to post pics on here I will throw some at ya if you are interested. Only one thing, can't show you the pictures of the guts, proprietary and confidential. Just kidding. Actually I don't have any gut pics is the real reason.
Thanks
JJ

KWiKSand
08-28-2006, 12:19 PM
Simply hit "New Reply" rather than Quick Reply, and then use the Browse button to find the picture on your computer. Then hit the Add Attachment button. You can add up to 4 per post if I remember right.

bdkw1
08-28-2006, 01:14 PM
Post up!

WHat did you get the silent chain from?

JJ450S
08-28-2006, 02:43 PM
I hope this works, I am a newb. These are random pics of the car in various stages in no particular order.
JJ
p.s. Will post more on next post.

JJ450S
08-28-2006, 02:54 PM
Here are some more, I hate limitations!
JJ

JJ450S
08-28-2006, 02:56 PM
Sorry about this, forgot to add that the silent chain was custom through Ramsey Chain.
Feel free to ask any questions.
JJ

masterfabr
08-28-2006, 04:11 PM
Anyone can build a transfer case for 10 hp buddy.

Bullnerd
08-28-2006, 07:01 PM
I like it ,i'd like to have four of em to race around my backyard. :D

Whats the aluminum rim around the fuel cell?Some type of catch can.

rowycoracing
08-28-2006, 07:15 PM
Nice job! That SAE Mini Baja competition is a great practical learning experience even if the specs do severely limit your buggy size, cage design, allow only one engine choice etc. I know you guys are a top contender. Good luck with this year's competition! What's up with the West Division competition being somewhere in the Dakoda's this year? Someone needs to show the judges a map of the US and explain North, South, East and West. Washougal was a better choice ... and it is actually in the West!

yoshi
08-28-2006, 07:32 PM
Nice job! That SAE Mini Baja competition is a great practical learning experience even if the specs do severely limit your buggy size, cage design, allow only one engine choice etc. I know you guys are a top contender. Good luck with this year's competition! What's up with the West Division competition being somewhere in the Dakoda's this year? Someone needs to show the judges a map of the US and explain North, South, East and West. Washougal was a better choice ... and it is actually in the West!your a nerd for actually knowing all that information, just thought you should know.....





:mrgreen:

JJ450S
08-28-2006, 08:30 PM
Masterfabr, I almost wanted to take offense to your comment, I will not only because I do not know you and I feel you do not know much if anything about mini baja. Lets see your handywork, I want to see prints, tolerancing, sketches, design limitations, shock loading calculations, safety factors, stress numbers, design report, cyclic loading tests, metalurgical tests and results, make it meet specifications and rules, shall I continue? Not exactly "a transfer case for 10hp." Take a look at sae.org and find our rules, enlighten yourself and read through them for me. (absolutely no pun intended, just kind of hurt my feelings) (someone please refresh his mind about the new guy policy) :wink:

Bullnerd, the thing around the fuel tank (not a fuel cell, as per rules it has to be the original tank) is a splash shield, it routes spilled fuel to the ground to help reduce the risk of fire. They are sticklers about safety.

Rowrycoracing, Yoshi is right, you are kind of a nerd knowing all that stuff, most people have never heard of mini baja, I am proud of ya! :D

Yoshi, how bout it? Are you going to give it a shot? I wasn't trying to discourage you, heck, even I did it! Even if it is only for a 10 hp buggy!

rowycoracing
08-28-2006, 08:35 PM
Yep yoshi you nailed it ... 100% nerd here ... and damn proud of it! Ever see Revenge of the Nerds??? :lol:

Gene
08-28-2006, 08:36 PM
Welcome to the site and thanks for posting pics of your race car. Very interesting.
Gene

bdkw1
08-28-2006, 09:22 PM
That trans looks like it would take much more than 10HP!

So Does Ramsey chain also cary the gears? Assortment of sizes? Web site?

JJ450S
08-29-2006, 07:50 AM
Ramsey Chain offers just about anything you want as far as chains are concerned. They have an excellent support staff which are very willing to help with size or function for your applications. They build everything in-house to you specs (within reason).
The chain in my transmission is good to about 75 hp shock loaded and the planetary set is good to a little above 100 hp.

www.ramseychain.com (http://www.ramseychain.com)

Blade
09-01-2006, 02:18 PM
That is a cool little buggy JJ450S!

buggito
09-01-2006, 02:49 PM
JJ450S, I read about sae.org, this organisation is everywhere on the American continent and after all these reading better tell you that is a real challenge, congrat to be where you are, I saw some pic of a tranny, maybe it was yours, and better tell you it was a "chef d'oeuvre", i read that they take some "kid" with basic knowledge and have them built the buggy from scratch, they not only teach them how to put it together but also, as you write how to calculate and realize their idea;my hat to them, this organisation should be more know by the general public and supported by every technical school this will drag a lot of young soul out of the street.
One more time my hat down, and If I could ask, more pic of the tranny.