Bevel gear steering axle prototype

[NeoSlayer888]

Here is a prototype I made with my schools FDM.










It is part of my senior project, comparing a bevel gear driven knuckle to a standard u-joint knuckle. From what I have done it looks like it won't work well for a 1:1 crawler, because as the knuckle steers it rotates the axle shaft.

Do you think it has potential in a R/C setup? I understand that the same problems that plague a 1:1 version would still be present, but do the advantages outweigh the downfalls?

There is the possibility of 180deg of steering, but there is the problem mentioned above, also more parts = more $ and possible breakage. Tomorrow I will finish the last piece so I can attach a motor (380 can I think) and see how it steers under constant power, I am hoping that I don't discover some catastrophic problem.

I have posted a thread like this before but without the prototype, I hope this thread gets more responses then my other one. I just want some honest opinions about this type of setup, because I am considering making this type of axle for a 2.2 crawler. I could have any width I want (within the rules of course) and have excellent steering (considering the 2.2 class is limited to 2ws).

[bRIBEGuy]

I think it's a very interesting idea.

The steering advantage is quite clear, though there are 2 main issues I could see occuring:

1) The "throttle steer" that you mentioned.

2) Axle Link Location.

The steering might not be an issue with a typical crawler draglink setup. If no servo-saver was used, then the axle steer torque would be pulling against a locked servo. A decent servo should equivilate this into zero induced movement.

The issue with the links could be solved by mearly mounting the links further inwards on the axles.

If it's feasable for you to make these, then I'd say go for it.

[SlinkySam]

I have seen this before and the issue with the steering isn't a problem. The problem that you discovered exists with the feedback from your drive gear wanting to turn both the wheel and turn the knuckle (or whichever has least resistance). The knuckle turning issue can be resolved by using a worm gear setup on your steering drive or basically a setup that only allows input from one side of the gear. With a worm input, you can only turn the system from the worm gear side and not the drive gear side.

So now you have two advantages with this setup. First is your steering ability and second is your ability to lock your steering where it is at without any load on the servo itself (so you will never have steering wander from loads).

Pretty cool if you ask me. Now put a double sided bevel on the steering knuckle and turn it into a portalized design, then you would have something unique and Coooool!!!

So when do you go into production and when will it arrive at my door for testing?

-Sam

[NeoSlayer888]

Originally Posted by SlinkySam

The knuckle turning issue can be resolved by using a worm gear setup on your steering drive or basically a setup that only allows input from one side of the gear. With a worm input, you can only turn the system from the worm gear side and not the drive gear side.

Now put a double sided bevel on the steering knuckle and turn it into a portalized design, then you would have something unique and Coooool!!!

-Sam

Wow, thanks for the great reply. I would have never thought of such an excellent idea like the worm gear for the steering. What do you mean when you say double sided bevel? Is this what you are talking about:

[SlinkySam]

Hey very cool. That is pretty much what I was saying though I pictured it a bit different. That is an awesome design too. Where can I find more info about it?

As to your design, how are you going to end up making a true working version? You can't really use the Stereolithography parts since they aren't the strongest. I presume that is the method you made your parts with since I am not familiar with the FDM acronym.

Keep the information and progress coming.

-Sam

[NeoSlayer888]

Originally Posted by SlinkySam

Hey very cool. That is pretty much what I was saying though I pictured it a bit different. That is an awesome design too. Where can I find more info about it?

As to your design, how are you going to end up making a true working version? You can't really use the Stereolithography parts since they aren't the strongest. I presume that is the method you made your parts with since I am not familiar with the FDM acronym.

Keep the information and progress coming.

-Sam

I originally saw the picture in this thread on Pirate4x4.

If I do make the axle, I think I would use the spider gears from a maxx diff or something equivalent. The rest I should be able to fab together. As for FDM it stands for fuse deposition model, I think. With FDM the plastic is melted in the head and layered on a foam board. If I am not mistaken, stereolithography form the part in liquid plastic by shooting a laser at the point you want to harden.

[4RnrRick]

interesting prototype you got there. If "throttle steer" was a problem, could you reduce the effect by adding a second bevel gear below the first one. would that cause both bevel gears to rotate in opposite directions thus negating the throttle steer??? Just a thought.

[bustedcrawler]

What school are you going to man? Hell you damn high school has better equipment than Mines does! No Rapid Protoyers, no 3D printers, no FDM, nothing of that family of badazz stuff to be had in a "research" college. You are one lucky kid.

Oh yeah, sweet design. I wouldnt mind havin a closer look at it sometime. You using SolidWorks to design? Also are you having to import .IGES files to your FDM or does it take other formats?

[SlinkySam]

Originally Posted by bustedcrawler

What school are you going to man? Hell you damn high school has better equipment than Mines does! No Rapid Protoyers, no 3D printers, no FDM, nothing of that family of badazz stuff to be had in a "research" college. You are one lucky kid.

Oh yeah, sweet design. I wouldnt mind havin a closer look at it sometime. You using SolidWorks to design? Also are you having to import .IGES files to your FDM or does it take other formats?

From reading your post, it looks like he has a better English department also

It is pretty cool stuff. I am not too familiar with the FDM process myself. I wonder if the parts would come out strong enough for use on R/Cs.

As for the program, if you look at the first modeling pic, the tab at the bottom shows that he is using SolidWorks, although I guess he could have imported it in... but that would be down right silly. :-P

-Sam

[NeoSlayer888]

Originally Posted by 4RnrRick

interesting prototype you got there. If "throttle steer" was a problem, could you reduce the effect by adding a second bevel gear below the first one. would that cause both bevel gears to rotate in opposite directions thus negating the throttle steer??? Just a thought.

Just thinking about that, I don't think it will effect anything. Next week I will see if I can make another bevel, then I can try and see.

Originally Posted by bustedcrawler

What school are you going to man? Hell you damn high school has better equipment than Mines does! No Rapid Protoyers, no 3D printers, no FDM, nothing of that family of badazz stuff to be had in a "research" college. You are one lucky kid.

Oh yeah, sweet design. I wouldnt mind havin a closer look at it sometime. You using SolidWorks to design? Also are you having to import .IGES files to your FDM or does it take other formats?

I go to Eaglecrest in Centennial. Someone my teacher went to school with is a dealer for FDMs, they had a damaged model that just happened to be available when my school got a tech grant. It was supposed to go towards new computers, but the FDM was to good of a deal to pass up. I am using SW 2005, the FDM requires a .STL file.

Originally Posted by SlinkySam

I wonder if the parts would come out strong enough for use on R/Cs.

I have also been thinking about that. I think the parts are ABS plastic, I am not sure though. Next week I will ask my teacher.

[SlinkySam]

Originally Posted by 4RnrRick

interesting prototype you got there. If "throttle steer" was a problem, could you reduce the effect by adding a second bevel gear below the first one. would that cause both bevel gears to rotate in opposite directions thus negating the throttle steer??? Just a thought.

You wouldn't be able to turn then. For the knuckle to turn, both bevels would have to spin the same direction and since they can't, it would just hold it in one place. I had to think about that one for a moment.

-Sam

[bustedcrawler]

Originally Posted by SlinkySam

From reading your post, it looks like he has a better English department also
-Sam

You would be right there. There is no English Department at Mines, so the mere fact that he has one means it's better already. I also didnt goto school to learn how to write grammatically perfect papers. I learned how to get them close enough that spell/grammar check and a couple of proof readings would catch them. Also, you cant tell me that when you have been in a hurry you haven't made a mistake or two.

I also realized that he was using Solidworks after tha fact when I had a better chance to look over the post. But there are some major differences in the program versions too.



Also that is good to know that FDM needs a .STL, the rapid prototype machine that PING Golf uses needs .IGES files to produce parts.

[WRX821]

Originally Posted by bustedcrawler

There is no English Department at Mines..

Mines as in CO. School of Mines??

If so that place is bad to the bone.

[SlinkySam]

Originally Posted by bustedcrawler

Also, you cant tell me that when you have been in a hurry you haven't made a mistake or two.

Me make mistakes? Never Just yankin yer chain.

Originally Posted by bustedcrawler

I also realized that he was using Solidworks after tha fact when I had a better chance to look over the post. But there are some major differences in the program versions too.

I am looking at a job right now that might require Solidworks and I have no clue how it works, but it seems like I should start. I use Pro/E and AutoCad now and the difference between versions were more key strokes and some fancier features more than anything else. Seems like I can't keep up with versions though since I learn one and two new versions come out. Bah...



So any new advances on the Bevel design NeoSlayer888?


-Sam

[NeoSlayer888]

Originally Posted by SlinkySam

I use Pro/E and AutoCad now and the difference between versions were more key strokes and some fancier features more than anything else. Seems like I can't keep up with versions though since I learn one and two new versions come out. Bah...



So any new advances on the Bevel design NeoSlayer888?


-Sam

I have used SW 2003-2005 and most of the changes SEEM to be GUI related, or some little feature for a certain market/audience.

3rd period today I will finish my adaptor so I can hook up a motor to the axle. I want to see how it steers under constant rotation. After that I don't think there will be any progress on the FDM prototype. I still have to finish my project, there is not much left, I have to run Cosmos on the two axles and finish my PowerPoint.

Hopefully, after that I can talk to my teacher about making a pair of complete axles. I am not counting on that going through because there is no real school implementation. If I were to use a FDM in the real world it would be about $25 an hour, just the little thing I made took 4.5 hours. I don’t think the school would like to pay (6hr per side, 2 sides per axle, 2 axles = 24hr*25 = $600) to make something I would just play around with.

[savageman]

i dont know if u thought iof this but if the bevel gear is solid wont it spin the tire the opposite of the driveshaft. just seems like extra work to me.

[bustedcrawler]

Originally Posted by WRX821

Mines as in CO. School of Mines??

If so that place is bad to the bone.

Yep that is the place. I guess you could say its bad to the bone....I guess.

I have 2003 and that is what I have been using the most. GUI changes can be kinda rough if your not used to the program previously. I had a helluva time going from SolidEdge to SolidWorks, due to Buttcon placement.

Pro/E is sweet as can be, I learned a little bit of it from friends, because Mines thought it would be cool to cut out the Pro/E course after I had registered for it.

[perfictsib]

the torqe steer wont be a problem if you use a drag link going from one wheel to the other, as they will either try to push themselvs together or apart depending on the direction of travel. and the drag link will prevent this, make the axle it should work nice

[lilman]

awesome idea. i never realy thought of applying this idea to anything but a tractor. i drove a john deere 7410 one summer pulling a 'rake' trailer (for hay and straw) and its turning was amazingly sharp.

it seems that youve gotten to all the problems that i can think if except...what are you going to use to turn the hub that far? a servo has a limiter, i suppose you could stretch its limit to farther, but even if you did that you still couldnt get the hub to turn completely, could you?

or....you could run a regular servo without the limiter(like on the winche servos ) and run a custom servo horn that uses a gear that will hold a samll portion of chain(like a bike chain that can be run on gears) and run the chain to each hub that has a fixed gear on its pivoting axis(the vertical shaft the bevel rests on. then you would have total control of how far the hub swivels. but the only problem with that is that you would need a lock of some sort to hold the chain and servo in one place so that you wouldnt have bump steer or any of that stuff. and also this might be able to eliminate the need for a drag link

i dont know. its just an idea.

[shortbusjeep]

i was thinking of doing this to one of my rigs but it just seems im to busy and dont have the funds. but you could use a motor with a seprate esc to build a rack and pinion set up, seems like it would have lots of power and a unlimited range just foward and reverse. dunno if it would work.


sbj