Has anyone tried to run a power rack and pinion in a rock crawler to improve high speed handling? I'm trying to build an all around buggy that I can rock crawl, mud race ,dessert race , and maybe light street/gravel road use.

Has anyone tried to run a power rack and pinion in a rock crawler to improve high speed handling? I'm trying to build an all around buggy that I can rock crawl, mud race ,dessert race , and maybe light street/gravel road use.

The IFS cars all have Racks on them, as for solid axle the only one I know of is the one Shaffers is building for Lance right now.

Here is a picture, not cheap either. Probably why you don't see it much.

Definitely not cheap for an "experiment". Hopefully it works! :laughing:

We spent a lot of time trying to do this but could not work out a good way to get the steering shaft to the rack without too much complexity, bevel boxes, plunging shafts etc.

It would be ideal if I could get the shaft to tun along the line of the top link (minimise length changes) but still can't work out how to get the steering input from the column down to the top link frame mount.

Tim

I was thinking if I centered the input splines of the rack to center of axle then use a small pto slip joint with a bearing connected to a cross member on the frame of the buggy and u joints to the steering column. To see if it would work I am going to go to the junk yard and get a free rack and then if it works I will spend money one a howe or other quality rack. I was just wondering if anyone has tried and run this setup

... could not work out a good way to get the steering shaft to the rack without too much complexity, bevel boxes, plunging shafts etc.


Interesting to see how Shaffer's over comes this challenge.

We spent a lot of time trying to do this but could not work out a good way to get the steering shaft to the rack without too much complexity, bevel boxes, plunging shafts etc.

It would be ideal if I could get the shaft to tun along the line of the top link (minimise length changes) but still can't work out how to get the steering input from the column down to the top link frame mount.

Tim

Why not go with timing chain type setup?

How about a cable?

Why not go with timing chain type setup?

Wizard Steer Clear?
www.wizardsteerclear.com
http://www.wizardsteerclear.com/images/STEER_CLEAR_4_SIZEScropfr3.JPG

the problem discovered is when the axle flexes it will turn the wheels when you hold the wheel. little info from Curt LeDuc

Hah. Why not just mount a regular steering box back by the front link pivots and run the drag-link parallel to the links, attaching it to a non-crossover-type steering arm on the knuckle??? Was proven to work pretty well on the old straight-axle desert trucks.

Hah. Why not just mount a regular steering box back by the front link pivots and run the drag-link parallel to the links, attaching it to a non-crossover-type steering arm on the knuckle??? Was proven to work pretty well on the old straight-axle desert trucks.

Bluetorch is running this

???

how about hydro assist w/ 2 single ended cylinders cross connected. I'd say double ended but I don't like where and how they are mounted. Or at least how most are mounted. I've seen a 90 ish ford van in a junkyard that had the pitman arm swinging out front of the steering box. It was 2wd and independent front suspension. put you a big drop pitman arm on the box, so you'll have room for up travel. Unless you don't mind your track bar not being parallel to the ground. I like them level at ride height, some don't. A pass drop axle would also give you more clearance for up travel. Put the cylinders behind the axle. syncronize the cylinders and let'er eat.

I would like to see how they address body roll. When the body rolls it will try to steer the rig.

In theory the only way to get rid of steer caused by body roll is to run the steering shaft straight down to the axle.

We ran a steering box on the frame (4 bolt from Howe), a drag link to the opposite knuckle and a double ended ram that also served as the track rod.

As said up above, the steering effects of body roll and suspension flex were not good :eek:

Did allow us to get the vehicle registered as road legal in the UK :D

I like the Wizard steering thing, might have to start working this out again. Anyone have experience of these Wizard things? Do they have any play in them? That was our biggest problem with a bevel box.

Tim

How much bump steer you get will also depend on rack ratio. I dont think it would be an issue at crawling speeds but the front end cycling through the desert @ 80mph and the wheels moving in a direction I dont want them to sounds a little scary:eek:

How about a cable?


There are several major car companies that have patents on cable steering.

uspto.gov

Here is a picture, not cheap either. Probably why you don't see it much.

What am I missing?

Isn't this basically just a double-ended hydro ram where the tie-rods hookup in the middle of the ram instead of the ends?

What am I missing?

Isn't this basically just a double-ended hydro ram where the tie-rods hookup in the middle of the ram instead of the ends?

no, there is a rack and pinion that a steering shaft goes to on the axle.

When we first talked about mounting the TT rack on Lance's car we knew we were definately going to run into some issues. I've always kinda liked building stuff that is challengeing. Without putting much thought into it, the first thing you notice it the difficulty getting the steering shaft around the front of the motor. Our first plan for this was to make the car rear engine..but with the car being a 3 seater, that didnt work out. Second plan was to run the steering shaft to the diff and then have a dry sump belt go from an idler pully mounted on the housing to the input shaft on the steering rack. I know this sounds scary, but believe it or not, this is how most Pro-Four trucks are done, like Curt Leduc's. But then you have the issue of any articulation movement steers the car. So, really the only way around that seems to be mounting the rack with the input shaft pointing upward (toward the sky) and an elaborate steering shaft set-up. The car will most likely have a Y-link in the front to give us something that moves in a single access, with the suspension to mount the steering shaft to. I know the more Lance reads this he's 'FREAKING OUT' cuz he's spent an insane amount of $$$ on this system!! and I know alot of you guys are asking "why not just run a steering box??" We wanted something that had the good input feel of a TT rack and to do something that hadn't been done. I my opinion, running a steering box with a track bar is really the only good way to run a steering box. Most bell crank set-ups don't work well with alot of travel, and are too many moving parts for my taste!

Mike

That sounds like a world-class clusterfuck. What's the point? To do something that hasn't been done before? Sometimes there's a good reason...

Full rock donkey hydro on this Bunderson class 1. I asked him if he liked it and he said once he took the yellow tape stripe off the steering wheel and learned to move his hands he loved it.

http://tamor.us/members-rigs/albums/Miscstuff/Class_1.sized.jpg


I hope it works out though, Mike. It'll be hella cool.

I dig the challenge and keep thinking about a way to do it.

A hydraulic servo could used to turn the shaft, but then the road feel of the rack would be negated.

Cable operation sounds flexible but how much room does it take, how much does it cost and or how much time would it take to fab it up?

With the shaft pointed up, theoretically, a slip jointed shaft with u joints would work with the wish bone set-up upper arm mentioned. Maybe the best bet.

Not to be a wet blanket and not saying it can't be done, but it boils down to liability for me. You mentioned a third seat, does that mean junior is riding in the back?

this will never work.....:D

I dig the challenge and keep thinking about a way to do it.

A hydraulic servo could used to turn the shaft, but then the road feel of the rack would be negated.

Cable operation sounds flexible but how much room does it take, how much does it cost and or how much time would it take to fab it up?

With the shaft pointed up, theoretically, a slip jointed shaft with u joints would work with the wish bone set-up upper arm mentioned. Maybe the best bet.

Not to be a wet blanket and not saying it can't be done, but it boils down to liability for me. You mentioned a third seat, does that mean junior is riding in the back?


Yes, junior is riding in the back. The steering servo will be mounted to the chassis not the axle and if it lost the shaft from there down it will still steer like a full hydro set up.

IMO cable is definately the way to go (straight axle and rack). The current worlds fastest motorcycle (piston driven) uses 2 control cables for steering. I worked on that bike and can say its both smooth and accurate. Also,I know they arent 100mph truggy's but i have built several ski bikes all with cable steering and had zero issues.

The issue with cables is the housings. they need to be rigid and well routed (big loops like in a boat) sharp bends dont work.

however, you run a cog @ the steering wheel with end links to the cable and the opposite @ the rack on the axle. rotary to linear back to rotary motion.

We have been working on the concept for awhile but we realized that Shannon is no dummy... all things considered, its easier to build an IFS car that goes really fast and turns when you want it to.

Cables sound much mo betta.

My head hurts. Redesign, again...

Wizard Steer Clear?
www.wizardsteerclear.com
http://www.wizardsteerclear.com/images/STEER_CLEAR_4_SIZEScropfr3.JPG

HA... that's hilarious. dude's hole in the wall hoarder fab shop was about 200 yards from my old shop in sac. cool dude w/ some cool ideas!

Just go to your local boat mart and look at the dual steering cables on all the big outboard engines.The steering wheel works a dual cable rack back to the engine.Fab a rack at the steering wheel and fab a rack at the steering rack.Hmmmm got me thunkin now:smokin:

The steering servo will be mounted to the chassis not the axle and if it lost the shaft from there down it will still steer like a full hydro set up.
I know a orbital valve will control the cylinder because of the G rotor, but I didn't know a servo will control it alone. Never had one apart to see how it works. I thought it work more like a switch :confused:


The current worlds fastest motorcycle (piston driven) uses 2 control cables for steering. i have built several ski bikes all with cable steering and had zero issues.

however, you run a cog @ the steering wheel with end links to the cable and the opposite @ the rack on the axle. rotary to linear back to rotary motion.



Motor cycles and boats don't have a lot of rotation to deal with, so cables are better suited. The rack they're using is 1-1/2" turns lock to lock. (at least I think ours is) So it would need bell cranks (like you are saying).
That could work. The parts on the front axle might be a little vulnerable, however.

I wonder if there is some kind of positive displacement hydraulic set up where a master rotor turns a slave rotor?

...The steering servo will be mounted to the chassis not the axle and if it lost the shaft from there down it will still steer like a full hydro set up.I can see the system fighting itself if there is any articulation steer with the servo on one end and the box on the other. Also if the shaft is lost it will not act like full hydro; it will have no steering at all. The servo valve needs resistance on the torsion bar to open up the valves.

Here is another thread on the topic from last year
http://pirate4x4.com/forum/showthread.php?t=830153&highlight=fat+city+steering

Seen at Mercedes, Germany last week. SAE has been working on these for awhile

"The electronic steering controller carries out the commands from the segmented steering wheel quickly and precisely. the operation is based on a special toothed rack driven via V belts by two electric motors. If one fails the second one takes over to ensure the system remains fully functional......"


Current option with rack stub vertical and cable from dash is intreaging.

that looks expensive and cool

From Gen4x4
I think that adapting a boat cable steering system will have the least travel and articulation induced steering compared to all of the previsously mentioned systems. One down side is that some of these cables are designed for very little feedback which is what you are shooting for with a R&P.

I'm sure that someone can find a robust enough unit. Just fit both ends with the rotating assembly.
http://www.ultraflexgroup.it/old/ut/ultraflex/photo/p6Ak.jpg

http://www.ultraflexgroup.it/old/ut/ultraflex/photo/p6bk.jpg

There is even one for Camo.
http://www.ultraflexgroup.it/old/ut/ultraflex/photo/P9192814.jpg

If cables were used to operate a rack mounted on the axle, then it should offer the same kind of feedback you would get with traditional steering linkage. Right? I really like this idea.

I'd like to see someone use a bunderson hydro ram/rack on a rock buggy? I dont have any pics but I think it would be a good set up.

What's that all about Drew?

What's that all about Drew?

Bunderson rack/ram?

I'd like to see someone use a bunderson hydro ram/rack on a rock buggy? I dont have any pics but I think it would be a good set up.

I don't see any advantage to it other than looking cool unless you have a problem with buckling a standard double ended ram set-up.

I don't see any advantage to it other than looking cool unless you have a problem with buckling a standard double ended ram set-up.

seems like bending double ended rams is a problem with a lot of guys. They are not buckling, they are bending from the side load. You have to run a big piston rod, so you have to run a big cylinder bore.

A Bunderson Ram is basically a double ended steering ram, but the ends of the piston rod are mounted to the chassis (or axle housing) so that the cylinder moves when you steer. The cylinder is actually double walled so you can just weld to the outer cylinder. You do need to put a tab on the cylinder and slider on the chassis so the cylinder doesn't rotate. You can run a tie rod from the center of the cylinder to each knuckle or run a tie rod knuckle to knuckle and a drag link from the cylinder to the knuckle.

seems like bending double ended rams is a problem with a lot of guys. They are not buckling, they are bending from the side load. You have to run a big piston rod, so you have to run a big cylinder bore.

A Bunderson Ram is basically a double ended steering ram, but the ends of the piston rod are mounted to the chassis (or axle housing) so that the cylinder moves when you steer. The cylinder is actually double walled so you can just weld to the outer cylinder. You do need to put a tab on the cylinder and slider on the chassis so the cylinder doesn't rotate. You can run a tie rod from the center of the cylinder to each knuckle or run a tie rod knuckle to knuckle and a drag link from the cylinder to the knuckle.

I look at it like an eccentrically loaded column, but you make a good point. You could run a smaller cylinder and get the same work from it while designing out the bending issue. I've been kicking the idea around and was trying to figure out why it would be beneficial. I would set up up just like the desert cars do with a tie rod going to each knuckle.

seems like bending double ended rams is a problem with a lot of guys. They are not buckling, they are bending from the side load. You have to run a big piston rod, so you have to run a big cylinder bore.

A Bunderson Ram is basically a double ended steering ram, but the ends of the piston rod are mounted to the chassis (or axle housing) so that the cylinder moves when you steer. The cylinder is actually double walled so you can just weld to the outer cylinder. You do need to put a tab on the cylinder and slider on the chassis so the cylinder doesn't rotate. You can run a tie rod from the center of the cylinder to each knuckle or run a tie rod knuckle to knuckle and a drag link from the cylinder to the knuckle.

why have the tie rod or drag link attach to the body of the ram instead of the shaft?

quinn's buggy, CA_YJ uses a double ended ram with a tie rod and mounts the body to the axle, shaft to the tie rod.


http://pirate4x4.com/forum/showthread.php?t=863285&highlight=

but this doesn't answer the question of the rack/ram...

I'm wrapping my head around this and at risk of over simplifying the problem. Isn't the objective to get the rotation of the steering wheel to the R/P with minimal loss of feel? How about a rotational shaft? Think weed eater shaft. I have not done much research, but I believe the concept is solid. In two minutes of google, I found this http://www.fdrive.com.au/products/07/shaft.php
I'm not sure how much deflection they have through the shaft, but if it is minimal, it could be a good candidate. Food for thought.

Another link. Similar concept, but done by hydraulics. This should eliminate any slop at all. Pretty neat.

YouTube - Ultimate Flexible Drive Shaft (http://www.youtube.com/watch?v=HPrW2bzJBVw)

Bunderson rack/ram?

seems like bending double ended rams is a problem with a lot of guys. They are not buckling, they are bending from the side load. You have to run a big piston rod, so you have to run a big cylinder bore.

A Bunderson Ram is basically a double ended steering ram, but the ends of the piston rod are mounted to the chassis (or axle housing) so that the cylinder moves when you steer. The cylinder is actually double walled so you can just weld to the outer cylinder. You do need to put a tab on the cylinder and slider on the chassis so the cylinder doesn't rotate. You can run a tie rod from the center of the cylinder to each knuckle or run a tie rod knuckle to knuckle and a drag link from the cylinder to the knuckle.
Yeah, thanks. Have seen something like that before, but didn't know what it was called.

I'm wrapping my head around this and at risk of over simplifying the problem. Isn't the objective to get the rotation of the steering wheel to the R/P with minimal loss of feel? How about a rotational shaft? Think weed eater shaft. I have not done much research, but I believe the concept is solid. In two minutes of google, I found this http://www.fdrive.com.au/products/07/shaft.php
I'm not sure how much deflection they have through the shaft, but if it is minimal, it could be a good candidate. Food for thought.

Another link. Similar concept, but done by hydraulics. This should eliminate any slop at all. Pretty neat.

YouTube - Ultimate Flexible Drive Shaft (http://www.youtube.com/watch?v=HPrW2bzJBVw)

Ford pintos back in the day came with a flex drive coupler from column to box to clear the exhaust/accessories. Alot of hot rod guys use them, so they are getting hard to find.

Rick.

Flex drive to the top of axle to minimize articulation bump steer... Interesting Idea Moving along! Documented public information for those inclined to patent stuff to stop innovation for the next 17 years.

Great stuff guys.

The steering servo will be mounted to the chassis not the axle and if it lost the shaft from there down it will still steer like a full hydro set up.

Sorry that is not how it works. The steering servo applies assist force but it doesnt control volume or position like an orbital valve does. If you lost the shaft, then the ram could get input to push left or push right, but not to stay straight. It is pretty likely that it would send you to full lock in a big hurry. Also to give significant input you need some resistance down stream of the servo because it's input is how much torque you transfer through it.

Do you guys think the 6" ram will be a problem? System will need a very short steering arm. Will this cause problems with feedback?

posted this in the el chup build too...saw this on TTORA today on a sas'd 2010 tundra and it made me think of you guys :D

http://img403.imageshack.us/img403/677/tundra2.jpg (http://img403.imageshack.us/i/tundra2.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

With the shaft pointed up, theoretically, a slip jointed shaft with u joints would work with the wish bone set-up upper arm mentioned. Maybe the best bet.


I've seen that exact set-up on a lifted golf cart, the work was as hack as it gets, but the steering actually worked semi well. They did it so they could run a normal golf-cart rack with some homo-ghey air suspension, the thing had about 18" of travel with the air bags. I see no reason why the same concept wouldn't work on a go-fast crawler.

There are some old school stock-car steering reverse boxes/V-drives that are perfect for getting the steering shaft down to the axle via the link, but they're impossible to find (simple to make though), and don't solve the bump-steer issue from articulation.

posted this in the el chup build too...saw this on TTORA today on a sas'd 2010 tundra and it made me think of you guys :D

http://img403.imageshack.us/img403/677/tundra2.jpg (http://img403.imageshack.us/i/tundra2.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)


Do you have a link to this or the build by chance?

What ever happened with this?

Maybe these ideas are new enough that it will take some time to think them through. Most on this thread were chasing Hammers also.

I just came back from the garage and checked our thoughts about a Pinto type enclosed cable (Speedo cable). If you take a fairly rigid hose and put one end in the vise horizontally, you can test the twist (resistance) at the other end.

If you have the front rack input pointing back at the conventional,almost horizonta lplane, any straight axle articulation will translate into bump steer.

If you now bend the hose to simulate moving the input shaft vertical, then you will see that straight axle artiiculation will not initiate bump steer.

I remember my old Pinto cable/shaft as being rather straight. I wonder how much rotational torque you would loose by putting a 90' bend in it...maybe 100%...back to the garage. Try it the next time you are out there.


Also look to see what packaging problems this creates...There is a lot directly above an axle.

Me, I just decided to go IFS. :laughing:

All the cool kids are doing it:flipoff2:

I ended up running the Howe rock racing setup. Works much better than the system I had last year.

Ifs is already on the table.....:D

I can see that the ride with Roger N eliminated any thought of trail or cone dodging. We will watch to see who's center Lance uses for the IFS. $$ or $$$$. Lots of new tech in the last few months. It was probably worth the wait. We should see some action on that thread...???