Is there a Hyd valve that works with a steering wheel?

[CorvairGuy]

We all know how the steering on a bobcat works.
We also know how they can tear up yards too. ggg

I was wondering if someone made a valve for a four wheel hydraulic system that controls flow with the use of a steering wheel instead of joy sticks?

I'm thinking along the lines of equal flow/pressure to all 4 wheels when going straight. However, when you turn to either side - it would restict the flow/pressure on the side you are turning to, i.e. inside wheels. It would dump the access fluid back to the tank, while keeping the same flow/pressure going to the outside wheels, remaintaining the same speed.

 

[J_J]

The Power-Tracs do something similar. We use a steering wheel that turns a steering valve that pushes and pulls the front half to steer, using hyd cylinders.

There is no reason that you could not rig something to push or pull a lever on two motor spool valves, to make it go straight, turn left or right. The steering wheel only needs to turn about a quarter turn to turn the machine. I can envision a bracket that connects the two valves, and pivoted at the center to operate the operate the fwd, rev, left, and right. I believe the earlier Snapper Zero turn lawn mowers used a small toggle switch to steer the two hyd motors. I did a test drive on one many years ago.

PT's use something like this.

https://www.surpluscenter.com/item.asp?item=9-1880&catname=hydraulic

 

[nikdfish]

The old john deere "spin steer" mowers (like our SST18) use a steering wheel to control the rear hydro-2WD - the front wheels just being casters. Ground speed/direction was controlled by forward/reverse pedals. The steering effect was speed dependant w/greater wheel speed differentials for a given steering wheel position at lower speeds, lessor at higher speeds. At a minimal creep speed, turning the steering wheel would trigger the wheels to turn in opposite directions & allow an in-place rotation. I would guess that re-invention of this approach would probably be a non-trivial exercise ....

Nick

 

[zzvyb6]

There are several rotary hydraulic steering valves for sale on ebay that would work. these are used on various mowers, including my JD F935.

 

[CorvairGuy]

J J, I could be wrong but I don't think a one piece frame tractor would be able to turn tight with that setup.

The PTs benefit from the two piece with the pivot in the middle.

Being a mechanic I'm thinking of how a limited slip differential works on turns.

If one does not reduce the flow to a hydraulic motor - it will want ot spin more than needed - tearing up grass and making it hard to make the turn.

To help with a smoother transsittion in regaurds to the hyd motors while turning:

If I have hydraulic motors at each wheel, with e valve for 2X4 or 4X4 settings; I'm picturing when I turn the steering wheel it will reduce flow to the inside hydraulic wheels - making the outside ones have the most flow with some flow to the inside motors so when it is in 4X4 they all or working.

BTW - the steering wheel would still operate the linkage to the front suspension to turn the front wheels too.

Forgive me I'm having a real hard time putting these thoughts down.

 

[RJA.Ilex]

If the problem is that the skid steer is tearing up the yard then changing from levers to a steering wheel won't stop that happening.
The damage is because they skid to steer, reducing the severity of the turn while driving both wheels in the same direction restricts the damage due to lower skid demands.
I don't see how fitting the steering wheel helps!

 

[CorvairGuy]

If the problem is that the skid steer is tearing up the yard then changing from levers to a steering wheel won't stop that happening.
The damage is because they skid to steer, reducing the severity of the turn while driving both wheels in the same direction restricts the damage due to lower skid demands.
I don't see how fitting the steering wheel helps!

Hi RJA,

Sorry, I was merely using the skid steer to make a point.

I'm not that good at driving a bobocat, I can't be the only one out there.
If you don't get the sticks just right it can jump around and/or tear up yards becasue the pressure is not just right to each side.

I'm building a hydraulic garden tractor as a porject and to use for most things around our new farm.

It will be a learning project too, as I plan to post it online and maybe even have some helpers.

I want it to steer like a tractor or car for that matter.

With 2WD if I use ONLY hydraulic motors at each rear wheel - with NO differentail to help when making turns; I will have to find away to allow for the inside axle or in this case motor to not want to turn as fast/hard as the outside one - to keep it from spining and tear up the grass.

Also, If at all possible - I like to have the option of having and switching into 4WD when needed. There will be those times when the inside front and rear wheels will need to turn as slow as possible to allow the outside wheels to catch up.

LOL - I can't have the inside wheels always trying to beat the outside wheel to where I am heading... :laughing:

I'm hoping someone who reads this thread - will know of some type of valve, or complete setup, already out there:

1) to keep from having something custom made at a very high cost....

2) or me having to drop the idea and coming up with plan B...


Main reasons for unit.

a) learn from it and to have everything Corvair - i.e. even this tractor - because I already know how to work on them and have lots of Corvairs and parts to maintain what I already own.

b) to pull a large cutting deck over 10 to 20 acres - saving me time and not haivng a deck under the unit to be in the way for other stuff unlike our JD LA130 w/48" cut.

c) being able to use a snowblower on the front for the 75 foot long laneway during our cold winter, -40F temps, in comfort sitting in a small cab, heated by the air off the engine and a corvair gas heater for those real cold days.

d) a small to mid size hyd dump trailer

e) to put boats away for people every winter and then pull them out every spring

f) to pull my boat out and to put it away each time I'm done using it in the summer

g) to pull a log splitter anywhere on the property and run it off the hydraulics

 

[bbutcher]

Char-Lynn makes several such valves, as well as other manufacturers. They are rather pricey however. You might check the auto salvage yards in your area. I think most auto power steering columns have something similar to what you are describing, and it should be much cheaper.