Ted's Steering Upgrade, With A Twist

Discussion in 'Builds and Fabricators Forum' started by garage gnome, Jan 6, 2018.

  1. Jan 7, 2018
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    4,647
    I found a late 50's Chrysler pump that mounts to the back of the generator- some machine work involved to make it work though.

    [​IMG]
     
  2. Jan 7, 2018
    garage gnome

    garage gnome Rust polisher Sponsor

    Western MA
    Joined:
    Jun 19, 2009
    Messages:
    1,517
    Is that what you will be using on Tonk?
     
  3. Jan 7, 2018
    garage gnome

    garage gnome Rust polisher Sponsor

    Western MA
    Joined:
    Jun 19, 2009
    Messages:
    1,517
    Based on my understanding of all the info Howard provided, it appears all that servo does is, when turned, the resistance of the manual steering actuates the torsion valve inside the servo allowing hydraulic fluid to flow to the cylinder. It has nothing to do with how many times it is turned. Therefore, if I add a brake of some sort to the other side, it will have the same effect, opening and closing the valve.

    I had watched a youtube video on how a hydraulic steering control unit works, for like a backhoe or tractor with full hydraulic steering and thought this servo did the same thing, which it doesn't. Basically, its no different than a log splitter valve, 4 ports, one in, one out, one to one side of the cylinder and one to the other side. A hydraulic steering control unit needs to have equal volumes of fluid to work properly (that's why there are two cylinders!), whereas this servo doesn't.

    [​IMG]
     
  4. Jan 7, 2018
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    4,647
    Yup. There's some interference issues with the starter that will require milling a relief on the rear of the pump & I'll have to change the reservoir setup as it's on the "wrong" side of the pump (chrysler mounted the genny on the driver's side).

    I'm actually just using the pump & rear cover- oddly enough once I removed the brush holders the chrysler end cover fits a jeep generator perfectly.

    I actually don't see why this would not be doable on alternators as well.
     
  5. Jan 7, 2018
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    4,647
    [​IMG]


    In any power assisted steering setup there's three required parts- a source of hydraulic pressure, an ram actuator to provide the assist and a control system.

    Invariable the pressure is supplied by a pump.

    The assist ram may be a divorced hydraulic cylinder such as the Bendix/ Monroe units which attach to the tie rod or drag link, or, built into the steering box like the ever popular saggy.

    The control valve will be a slide or rotary spool valve which will be controlled by some sort of torque sensing mechanism which is positioned to sense the amount of resistance to turning between the steering gear and the steering wheel.

    There's many different ways of making this work- here's one way-



    upload_2018-1-7_23-18-54.png


    I don't think the brake idea will work for you that well as first it can't sense the torque on the steering gear and, if I have this in my head right, then putting the brake on the "upper" end of your valve will result in opposite force to what you want- maybe switching the lines/ports would fix that. However , again if I have this right in my head, having the brake may result in "return to center" issues.
     
  6. Jan 8, 2018
    Keys5a

    Keys5a Sponsor Sponsor

    Joined:
    Jan 23, 2014
    Messages:
    1,151
    I still am of the opinion you are making this overly complicated. Look at ebay# 1522 5246 9432 '69 Mustang power steering cylinder. The control valve is an integral part of the cylinder assembly. Its probably the Bendix unit Howard was thinking about, but much simpler than his included diagram showing operation. The "tie rod end" portion you see in the ebay image is the shuttle valve (see edit below) making this very compact and effective as an assist cylinder. All you need after fitting this cylinder is the pump and hoses to connect. I could see this unit used in place of the drag link before the bellcrank. The 2 hoses would complicate things if it were used in place of a tie rod after the bellcrank, but that is what you are essentially doing as seen in your photo in post #7.
    I think the cylinder assembly that I used on our Kubota years ago had an 11/16" threaded end instead of the two rubber bushings (or maybe I made an adapter). I just used a tie rod adjusting sleeve to connect a long tie rod end from a Chevy to make the rod length I needed. I my Kubota application, the cylinder assembly became the drag link.
    I have seen heavier versions of this assist cylinder on medium duty trucks, but don't remember the application.
    Just something else to consider...

    EDIT: I found the "other" part I was missing. Check out ebay #1923 9766 9437 for the shuttle valve that operates the cylinder I referenced above. I knew I threaded a tie rod on. I mistakenly stated the cylinder had the shuttle valve as an integral part. I still think this shuttle valve would make a very simple power drag link for a Ross steering system.
    -Donny
     
    Last edited: Jan 8, 2018
  7. Jan 8, 2018
    garage gnome

    garage gnome Rust polisher Sponsor

    Western MA
    Joined:
    Jun 19, 2009
    Messages:
    1,517
    I found the cylinder on eBay. So the end with the rubber bushings gets attached to the frame and the other end gets attached to the steering?

    I’m also assuming the two lines on that cylinder are the feed and return lines?
     
  8. Jan 8, 2018
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    4,647
    Sorry no, that's just the cylinder, the control valve is a separate part that looks lit this-


    [​IMG]

    The tierod end you see would normal connect to tierod like this-


    [​IMG]

    Using this on a jeep would require a one piece tierod setup. The tapered stud on the valve would fit into the bellcrank & the steering link to the passenger side knuckle threads into the end. Something would have to be fabbed to mount the cylinder to the frame or axle for the fixed end & an connection to the tierod. I've got one of these exact cylinders kicking around somewheres' as well as the valve, I may use one or both on my conversion but the downsides to these are-

    - Hoses. As the valve & cylinder move the hoses get stressed & strained- they do eventually start leaking.
    - PTO winch. If you have a PTO winch, especially a Ramsey, there's a fitment issue with clearance between the valve body/hoses & the PTO drive shaft.

    Nate may be taking the road less travelled on this but I say Good for Him. :) He's going to learn on this & may come up with a another trick or two we can all benefit from.
     
    cadwelder likes this.
  9. Jan 8, 2018
    cadwelder

    cadwelder Member

    Milton KY
    Joined:
    Jun 2, 2011
    Messages:
    149
    There needs to be "feedback" in a power steering system. Hydraulic pressure is to provide the force, and the amount of force when needed, and this force is to be removed when no longer needed. The relationship between the pitman arm and valve/cylinder in this diagram Howard provided shows this.
    20180108_122705.png
    The pitman arm moves the valve (either way), which pressurizes the cylinder, which steers the wheels until the springs center the valve and removes pressure.

    A servo valve in parallel with the steering column/shaft will have no feedback, brake or no brake.
     
  10. Jan 8, 2018
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    4,647
    Nate, I might have a simple (ish) way for you to use that valve you bought based on an idea I had a while back for something similar to what you want to do. Give me a bit to come up with a drawing to explain it.
     
  11. Jan 8, 2018
    jeepstar

    jeepstar Member

    Sheboygan
    Joined:
    Jun 28, 2006
    Messages:
    724
    :watch: this is why I come here :)
     
    Focker likes this.
  12. Jan 8, 2018
    garage gnome

    garage gnome Rust polisher Sponsor

    Western MA
    Joined:
    Jun 19, 2009
    Messages:
    1,517
    Ugh..... this is so confusing now... I should just ditch the whole idea before everything is welded solid.

    And yes I do have a Ramsey pto winch, but I modified my tub so the driveshaft goes up the passenger side.
     
  13. Jan 11, 2018
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    4,647
    Still working on this, should have it ready tomorrow.

    It'll be worth the wait :D
     
  14. Jan 11, 2018
    garage gnome

    garage gnome Rust polisher Sponsor

    Western MA
    Joined:
    Jun 19, 2009
    Messages:
    1,517
    Sounds good Howard. I'll be looking forward to seeing it!
     
  15. Jan 12, 2018
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    4,647
    OK, I'm tired of making drawings so let's go with what I got.

    The heart of the system is the spool valve. It controls the flow of fluid from an input port to an output port based on it's movement. Here's a drawing of a regular spool valve, as you can see sliding the valve to a small degree causes the cylinder to move. This type of valve is used in the Ford & Bendix units; the spool is mechanically connected to the steering tie rod with one end connected to the rod & the other to the steering gear. It is held centered by springs in the neutral position until the steering gear applies a force to move it. When it does move the cylinder applies pressure to the steering rod until it matches the force applied to the spool which allows the springs to move it back to center position shutting off flow to the cylinder. In the real world the spool only moves a fraction of an inch to open full flow to the cylinder. Note that the strength of the springs is what determines the "road feel" as they determine how much force has to be used to move the spool- Chrysler used very light springs resulting in "Novocain Numb" feeling steering, GM went with heavier springs giving a heavier feel.

    upload_2018-1-12_13-39-24.png

    In your case you've acquired a rotary spool valve; a rotary spool consists of three parts- case, inner spool & outer spool. The spools nest together & fit inside the case. Each spool connects to a shaft, they stick out of the case on opposite ends; the shafts are tied together with a torsion bar or springs- in your case it's a 1/8" torsion bar. The torsion bar means that when you twist one shaft the other one wants to turn with it & thus keep the spools in alignment. The torsion bar determines road feel the same as the springs do in a Bendix/Ford spool valve- your 1/8" torsion bar will present a very light road feel.

    The valve outputs pressure to the cylinder when the shaft on one end rotates in relationship to the shaft on the other end changing the alignment of the spools & allowing fluid under pressure to to move to the output ports towards the cylinder.

    Here's a drawing of a rotary spool valve that in absolutely every detail does not represent a real valve's insides or operation in any way.

    upload_2018-1-12_13-24-31.png



    Let's look at he stock steering column- upload_2018-1-12_13-54-28.png

    We've got the worm shaft, bearings and steering tube. Assume the front wheels are between a rock & a hard place- you apply pressure to the steering wheel but they don't want to move, here's what happens-

    upload_2018-1-12_13-57-11.png
    The worm shaft actually twists to a slight degree, exaggerated here for clarity. The important part is there's rotational movement of the top end relative to the bottom.


    Here's how your spool valve is intended to be installed-

    upload_2018-1-12_14-1-39.png

    It sits in the middle of the worm shaft, any difference in torque between the steering wheel & worm moves the spools relative to each other allowing fluid to flow to the cylinder-

    upload_2018-1-12_14-5-7.png
    In reality the spool valve itself will only have to twist a degree or so to operate.



    To be continued...
     

    Attached Files:

    Last edited: Jan 12, 2018
    cadwelder and ITLKSEZ like this.
  16. Jan 12, 2018
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
    Joined:
    Aug 13, 2015
    Messages:
    1,809
    :beer:
    I was expecting scribbles on cocktail napkins. :bow:
     
  17. Jan 12, 2018
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    4,647
    Continued...

    Now here's what you planned-
    upload_2018-1-12_14-6-15.png
    As we soused out this won't work as there's no torsion applied across the valve, turning one shaft results, thanks to the torsion bar, in the other shaft turning as well resulting in no net miss-alignment across the spools & subsequently no fluid movement to the output ports. :( The idea of the brake would allow the system to work until you wanted to stop turning at which point you'd be in for a very exciting time.


    Now, as pointed out in the previous post, the worm shaft itself will act as a torsion element; I think this is what you have to take advantage of to make you setup work. You can do this by adding a piece of tube affixed to the worm shaft just under the upper support bearing & connecting the bottom end of it to the other shaft on you valve. Note the alignment of the red & yellow lines- red is the shaft, yellow is the tube.
    upload_2018-1-12_14-12-59.png

    Now when you turn the wheel the new tube transmits the difference , or twist, in the worm shaft to the second shaft of your valve thus introducing the differential inputs required to make the valve operate.
    upload_2018-1-12_14-29-24.png
    The tube transmits the twisted position of the top of the worm shaft to the other shaft of the the valve, therefore the valve "feels' the twist of the the worm shaft and the spools move relative to each other allowing for fluid flow to the cylinder.

    I suspect road feel would be heavier than if the valve was inserted into the worm shaft & you were wholly reliant on the internal 1/8" torsion bar, what you'll end up with will be mostly dependent on how much the worm shaft twists for a given amount of effort; if too light you could try making the tube shorter & attach it lower down the worm shaft, if too heavy you could, you could.. well I don't know what you could do. :shrug: You might want to grab an old steering box & shaft & bench experiment a bit.



    If you find you have a space issue between the Ross box & floor sheet metal you might try this-
    upload_2018-1-12_14-24-33.png

    Hope this helps you out with deciding if/how to proceed, if it works I might try the same setup. :)



    Now if you'll excuse me I'm going to take some aspirin & have a little lie-down. :sleep:
     

    Attached Files:

    Last edited: Jan 12, 2018
    cadwelder likes this.
  18. Jan 12, 2018
    Focker

    Focker Rust Never Sleeps Staff Member Sponsor

    Tri-Cities WA
    Joined:
    Aug 18, 2014
    Messages:
    4,492
    Nice doodles Howard. o_O
     
  19. Jan 12, 2018
    TIm E

    TIm E Sponsor Sponsor

    NW Arkansas
    Joined:
    Mar 2, 2017
    Messages:
    122
    Impressive explanation and visuals! Howard, where do babies come from? :whistle:
     
    cadwelder likes this.
  20. Jan 12, 2018
    Rich M.

    Rich M. Member

    Maryland
    Joined:
    Mar 23, 2008
    Messages:
    264
    Master
     

Share This Page

New Posts