RCCrawler Forums

Mechanicalbob · 10-06-2006, 04:29 AM

Here is a link to find the gears for the servo and the rack as well. Great idea, only thing I would do is leave the servo stock not a consant turn. If you where to leave it stock it would center it self and the wheels at the same time.

Steve

S-Dog · 10-06-2006, 06:54 AM

Quote:

Originally Posted by Mechanicalbob

Here is a link to find the gears for the servo and the rack as well. Great idea, only thing I would do is leave the servo stock not a consant turn. If you where to leave it stock it would center it self and the wheels at the same time.

Steve

The problem with that is you lose the mechanical advantage of the 700 degrees of rotation instead of the 60 degrees... AND the wheels would barely turn.

TwistedXT · 10-06-2006, 08:41 AM

Quote:

Originally Posted by Unholy

The big question is how will you return to center?

the pot that is mounted on the axle....

Unholy · 10-06-2006, 08:43 AM

Quote:

Originally Posted by TwistedXT

the pot that is mounted on the axle....

Everyone keeps saying the pot on the axles returns it to center....

If the thing has constant rotation hows it going to know where to center it?

Double J · 10-06-2006, 09:38 AM

I love this.

If I can help in anyway to get this thing working Please let me know.

Kamikaze · 10-06-2006, 10:57 AM

Quote:

Originally Posted by Unholy

Everyone keeps saying the pot on the axles returns it to center....

If the thing has constant rotation hows it going to know where to center it?

Because the pot is picking up the movment of the slave cylinder and not the servo, it is basically tricking the servo into turning more times than it thinks it is. So it will hold center and will accept proportional input from the rx.
As far as it being squishy it wont be. yuo cant compress the fluid and even if you put enough force on the slave it will still have to move the master cylinder through all that gear reduction, so it wont move.

JasonInAugusta · 10-06-2006, 11:37 AM

Will be cool to see it work.

Keep chuggin' along on it.

Wally · 10-06-2006, 08:36 PM

Quote:

Originally Posted by run2jeepn

Those sties are cool, but I can't read any of them. Damn Germans

The site www.Wolfhart.us has a German and an English part.
You may see also videos from new and exiting pump principles.
http://www.youtube.com/results?searc...&search=Search

nd4spdbh · 10-08-2006, 11:45 AM

freakin amazing idea dude.... i could see this working out very good... i see no probs in it at all.... but couldnt you just completly take out the whole hydraluics and go to a rack and pinion style steering.... its exactly the same thing becides the hydraulics lol.

but this is a very cool idea... go with the hydraulics .... ALSO if your master and slave cylinders are identical you can move the POT to the master rack to get the electronics off the axle... seems as how liquid does not compress so the movement of the master and slave rack should in theory be identical.

Kamikaze · 10-08-2006, 11:52 AM

Quote:

Originally Posted by nd4spdbh

freakin amazing idea dude.... i could see this working out very good... i see no probs in it at all.... but couldnt you just completly take out the whole hydraluics and go to a rack and pinion style steering.... its exactly the same thing becides the hydraulics lol.

but this is a very cool idea... go with the hydraulics .... ALSO if your master and slave cylinders are identical you can move the POT to the master rack to get the electronics off the axle... seems as how liquid does not compress so the movement of the master and slave rack should in theory be identical.

Yeah I thought of that the other day, at first I was going to use different size cylinders but theres enough reduction in the rack and pinion system, I guess this is really a hybrid hydrolic/rack and pinion system.

nd4spdbh · 10-08-2006, 06:05 PM

Quote:

Originally Posted by Kamikaze

Yeah I thought of that the other day, at first I was going to use different size cylinders but theres enough reduction in the rack and pinion system, I guess this is really a hybrid hydrolic/rack and pinion system.

yup esentially it is... but the nice thing about it is the fact you can get ALL electronics off the axle.... and then you can (if you have tlt axles) swap the hubs from left to right to put the pistion behind the axle and get the acramen angles right.... then you dont have to worry bout dinging up the cylinder!

4link4eva · 10-09-2006, 09:56 AM

Cool, if a bit over-complex. Why not just have the servo horn attached to a piston, which forces fluid through a hose, to the axles, like this:

Get it?

Cheers 8-)

Highmark · 10-09-2006, 10:03 AM

Because you loose any mechanical advantage that you would gain.

4link4eva · 10-09-2006, 10:07 AM

O-kay, how about if you had the piston on the axle larger than the one on the servo? This would increase the pressure.

Cheers 8-)

Kamikaze · 10-09-2006, 05:07 PM

You simple can't make more power if the servo is moving the same distance. If you use a bigger master like you have drawn it would make more torque at the expence of linier movement. You would get more torque but the cylinder will only move like .05" of an inch. Thats what makes the power multiply, its like a snatch block for a wench, you have to pull 100 ft of cable to move 50 ft but you have twice the power.

Update, I managed to locate some cylinders today, 9/16" bore with a 1-1/2" stroke. I got them on order along with 2 feet of 48 pitch rack gear, so now that I don't have to make that stuff, I can get along with this project sonner than I thought.

Mechanicalbob · 10-09-2006, 06:34 PM

Where did you find the cylinders? can you post a picture or a link?

Steve

Kamikaze · 10-14-2006, 03:04 PM

Ok, made some progress. I have modified the servo by removing the stops so that it can rotate continously, and I have removed the POT. Now the servo will turn untill the Pot lines up corectly. I was glad to see that the pot will work the way I thought it would, it will be easy to attach an arm to it and it should fit nicely above the kingpin inside the rim away from any harm. It takes 60 degrees for the pot to move lock to lock so it will be perfect to pick up the movement of the slave cylinder. Also I was concerned about the speed of this setup, but I think it will be good, it will turn the servo 540 degrees to go from center to full right or left and it takes this servo 1.25 seconds unloaded to turn 540 degrees, so it will realisticly take 3 to 4 seconds to go from lock to lock. But that is about the same as a 1/4 scale servo when you aren't moving.

Also nice is that the cylinders are 1.5" stroke so if you change the length of the arm on the pot you can increase or decrease the amount of "throw" in the steering.

anyway heres the pics of the modded servo and a video to show how the pot will make it all work. Oh yeah the cylinders and the rack gear should be hear this week so I can start machining the rest of it. Torque estimates with a 42 oz. in servo are around 800 oz. inches.

http://media.putfile.com/servo

EMUTT · 10-14-2006, 03:56 PM

I want some of those if you start to sell them thats awesome.

Thorsteenster · 10-14-2006, 04:15 PM

where did you get the cylinders from? hmm, so this setup could easily be adapted to other things that would be much simpler to setup than steering, like maybe a hydraulic dump bed or somthing

Kamikaze · 10-14-2006, 04:23 PM

I get them in town.

10-14-2006, 03:04 PM	#37
Kamikaze I wanna be Dave Join Date: Oct 2005 Location: Columbia TN Posts: 6,154	Ok, made some progress. I have modified the servo by removing the stops so that it can rotate continously, and I have removed the POT. Now the servo will turn untill the Pot lines up corectly. I was glad to see that the pot will work the way I thought it would, it will be easy to attach an arm to it and it should fit nicely above the kingpin inside the rim away from any harm. It takes 60 degrees for the pot to move lock to lock so it will be perfect to pick up the movement of the slave cylinder. Also I was concerned about the speed of this setup, but I think it will be good, it will turn the servo 540 degrees to go from center to full right or left and it takes this servo 1.25 seconds unloaded to turn 540 degrees, so it will realisticly take 3 to 4 seconds to go from lock to lock. But that is about the same as a 1/4 scale servo when you aren't moving. Also nice is that the cylinders are 1.5" stroke so if you change the length of the arm on the pot you can increase or decrease the amount of "throw" in the steering. anyway heres the pics of the modded servo and a video to show how the pot will make it all work. Oh yeah the cylinders and the rack gear should be hear this week so I can start machining the rest of it. Torque estimates with a 42 oz. in servo are around 800 oz. inches. http://media.putfile.com/servo Attached Images Last edited by Kamikaze; 10-14-2006 at 03:08 PM.

10-06-2006, 04:29 AM	#21
Mechanicalbob Quarry Creeper Join Date: Mar 2006 Location: Juneau Alaska Posts: 244	Here is a link to find the gears for the servo and the rack as well. Great idea, only thing I would do is leave the servo stock not a consant turn. If you where to leave it stock it would center it self and the wheels at the same time. Steve

10-06-2006, 09:38 AM	#25
Double J I wanna be Dave Join Date: Dec 2005 Location: between heaven and hell. Posts: 3,367	I love this. If I can help in anyway to get this thing working Please let me know.

10-06-2006, 11:37 AM	#27
JasonInAugusta 06 Super National Champ Join Date: Jun 2004 Location: Stark Industries Bar and Grill Posts: 11,361	Will be cool to see it work. Keep chuggin' along on it.

10-08-2006, 11:45 AM	#29
nd4spdbh Rock Crawler Join Date: Mar 2005 Location: Dude on my dirt bike in SoCal!!! Posts: 949	freakin amazing idea dude.... i could see this working out very good... i see no probs in it at all.... but couldnt you just completly take out the whole hydraluics and go to a rack and pinion style steering.... its exactly the same thing becides the hydraulics lol. but this is a very cool idea... go with the hydraulics .... ALSO if your master and slave cylinders are identical you can move the POT to the master rack to get the electronics off the axle... seems as how liquid does not compress so the movement of the master and slave rack should in theory be identical.

10-09-2006, 09:56 AM	#32
4link4eva RCC Addict Join Date: May 2006 Location: In England, looking for the threadlock... Posts: 1,150	Cool, if a bit over-complex. Why not just have the servo horn attached to a piston, which forces fluid through a hose, to the axles, like this: Get it? Cheers 8-)

10-09-2006, 10:03 AM	#33
Highmark I wanna be Dave Join Date: Jan 2004 Location: Austin Texas Posts: 3,866	Because you loose any mechanical advantage that you would gain.

10-09-2006, 10:07 AM	#34
4link4eva RCC Addict Join Date: May 2006 Location: In England, looking for the threadlock... Posts: 1,150	O-kay, how about if you had the piston on the axle larger than the one on the servo? This would increase the pressure. Cheers 8-)

10-09-2006, 05:07 PM	#35
Kamikaze I wanna be Dave Join Date: Oct 2005 Location: Columbia TN Posts: 6,154	You simple can't make more power if the servo is moving the same distance. If you use a bigger master like you have drawn it would make more torque at the expence of linier movement. You would get more torque but the cylinder will only move like .05" of an inch. Thats what makes the power multiply, its like a snatch block for a wench, you have to pull 100 ft of cable to move 50 ft but you have twice the power. Update, I managed to locate some cylinders today, 9/16" bore with a 1-1/2" stroke. I got them on order along with 2 feet of 48 pitch rack gear, so now that I don't have to make that stuff, I can get along with this project sonner than I thought.

10-09-2006, 06:34 PM	#36
Mechanicalbob Quarry Creeper Join Date: Mar 2006 Location: Juneau Alaska Posts: 244	Where did you find the cylinders? can you post a picture or a link? Steve

10-14-2006, 03:56 PM	#38
EMUTT Rock Crawler Join Date: Mar 2006 Location: Benson,NC Posts: 761	I want some of those if you start to sell them thats awesome.

Sponsored Links

10-14-2006, 04:15 PM	#39
Thorsteenster I wanna be Dave Join Date: May 2006 Location: Arlington, VA Posts: 3,377	where did you get the cylinders from? hmm, so this setup could easily be adapted to other things that would be much simpler to setup than steering, like maybe a hydraulic dump bed or somthing

10-14-2006, 04:23 PM	#40
Kamikaze I wanna be Dave Join Date: Oct 2005 Location: Columbia TN Posts: 6,154	I get them in town.

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