Hydraulic Steering

[teemu]

I have searched for hours on this topic and decided it would be easiest to join this forum and ask the question directly.

In theory, if I wanted to put hydraulic steering on a lawn tractor (no power assist). Could I use a bi directional gear pump turned by the steering wheel, with each hose running to a double ended, double acting cylinder (equal volume on each side). As I turned the wheel, the volume lost on one side of the cylinder would just shifted to the other side. I expect that there would be pressure build up in the system and don't know how I would relieve that pressure because there would be no reservoir?

Also, is there a way I could add a reservoir to the system to be able to pressure release fluid to?

If you think of a boat helm steering system, I am essentially trying to replicate that?

 

[wdchyd]

Instead of reinventing the wheel why not just add a marine steering helm to your lawn tractor?. Seastar makes great stuff, I converted my fishing boat last year from cable steer to hyd steering with ease with a used cylinder and helm. The only thing you will need to do is either convert an existing marine cylinder or codger up a small 1.500" (or approx.) bore cylinder, double ended hyd rod will be sweeter steering cuz the displacement will be equal on the lock to lock.

I believe there is no pressure relief in marine steering cuz you are manually the source of the hyd power

 

[teemu]

The sea star helms are at least $350 so I just was thinking a gear pump would be a cheaper option

 

[wdchyd]

The sea star helms are at least $350 so I just was thinking a gear pump would be a cheaper option

that's for new.....plenty of old boats out there, mine was free cuz the previous owner repowered with a new outboard complete with new steering

 

[wdchyd]

If you did use a standard b-rot gear pump you'd have to fashion up check valves to control the flows from suction to discharge when turning different directions, which would have to be incorporated in the reservoir with the gear pump submerged in oil.

 

[teemu]

Why would the gear pump have to be submerged?

 

[sandman2234]

I agree, don't re-invent the wheel. There are too many around used to try to make something work.
If you weren't so far away, I would say come get the one I have. It is under a Jacobsen Reel mower that I stripped. It had hydraulic everything, so having power steering was just an add-on. Look around, bound to be something close!
David from jax

 

[wdchyd]

Why would the gear pump have to be submerged?

Well if ya didn't the reservoir would have to be mounted above the gear pump to work. I have seen older scissors lifts (Heff-T Herman, MEC) that used a standard two port eaton hydraulic motor to manually power a steering hyd cylinder, the small reservoir for make up oil was mounted on the side (maybe 4 to 6 oz)

 

[teemu]

Where would the reservoir feed into in a two port motor?

Sorry for all the questions. Appreciate the replies!

 

[wdchyd]

A two port hyd motor would work the same way as two port bi-rotational gear pump.