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Hydraulic gear pump/motor as a steering pump?

larboc

larboc

Limestone cowboy
Joined
May 19, 2020
Member Number
237
Messages
830
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Da yoop
Considering putting hydraulic steering on my boat and real marine hydraulic steering systems are ridiculously expensive for what they are. Units for 150hp+ non-power steering sterndrives are less common and even more expensive ($1000+). It's not a power steering system, just a helm pump and a cylinder at the tiller. I can't see any reason that a small displacement hydraulic motor or bi-directional gear pump wouldn't work at the helm, and a small steering cylinder at the tiller. Even buying new I'd be at less than half the cost of marine stuff and have heavier duty parts. The left over money could be used elsewhere, possibly add an autopilot (most require hydraulic steering)
 
larboc said:
Considering putting hydraulic steering on my boat and real marine hydraulic steering systems are ridiculously expensive for what they are. Units for 150hp+ non-power steering sterndrives are less common and even more expensive ($1000+). It's not a power steering system, just a helm pump and a cylinder at the tiller. I can't see any reason that a small displacement hydraulic motor or bi-directional gear pump wouldn't work at the helm, and a small steering cylinder at the tiller. Even buying new I'd be at less than half the cost of marine stuff and have heavier duty parts. The left over money could be used elsewhere, possibly add an autopilot (most require hydraulic steering)
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I've had a couple wacky situations where I wanted to use a hydraulic motor and a hand wheel to drive a cylinder or another hydraulic motor. I never got around to building anything but I could never come up with a good reason it wouldn't work for human driven input speeds.
 
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When I was a GSE tech most of the ramp trucks and a lot of GSE in general had a hydro pump driven by the motor. I suspect high rpm may be an issue with cavitation or heat but it all worked great on The equipment we serviced.
 
crisbee1 said:
Definitely possible, What kinda boat/motor?
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22' fiberglass cabin cruiser, 188hp mercruiser. The hull likes to wander when trolling, not much keel to it, it's extremely sensitive to any play in the stern drive's steering. I put a new NFB rack and cable in which helped, but there is still enough play in the cable steering to make it a PITA to keep it going in a straight line.
 
what about using an ardupilot and a motor to give you automatic steering and course correction?
 
crisbee1 said:
Why not a power steering pump?
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Every PS pump I've taken apart looked to me like they would only work in one direction. I think the vanes are pressure balanced from the output so I think you'd only be able to turn one direction.
 
larboc said:
Every PS pump I've taken apart looked to me like they would only work in one direction. I think the vanes are pressure balanced from the output so I think you'd only be able to turn one direction.
Click to expand...

Nah thats why you use a rotary valve.

If thats your thought on ps pump the hydro pump is the same thing...they are the same thing.

Your looking for hydrostatic which is $$$ which uses a pump and a swash plate to change the direction...but not backwards...just out of a different port.
 
crisbee1 said:
I must have missed why it needs to run backwards.
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I think you missed that it isn't a power steering system, only a human powered steering wheel pump that connects to a cylinder. The only thing turning the pump is a steering wheel attached to the shaft.
 
A_G said:
Nah thats why you use a rotary valve.

If thats your thought on ps pump the hydro pump is the same thing...they are the same thing.

Your looking for hydrostatic which is $$$ which uses a pump and a swash plate to change the direction...but not backwards...just out of a different port.
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Not really, have you ever had the vane pump part of a saginaw p-pump apart? It relies on the output pressure to seal the vanes so if you went make a left hand turn, the fluid would just bypass the vanes. Simple bi-directional gear motor/pumps I've had apart done't care, but I'm not sure if the lobes would result in pulsing or dead spots in the wheel.

Hydrostatic pump wouldn't make any sense since it's all going to be hand powered.
 
so a 12volt column power steering motor out of a junkyard car would work. I had a 1992 22 ft Maxum sc, I didn't troll with it however at no wake speed and a little chop it wandered a lot.
 
larboc said:
Not really, have you ever had the vane pump part of a saginaw p-pump apart? It relies on the output pressure to seal the vanes so if you went make a left hand turn, the fluid would just bypass the vanes. Simple bi-directional gear motor/pumps I've had apart done't care, but I'm not sure if the lobes would result in pulsing or dead spots in the wheel.

Hydrostatic pump wouldn't make any sense since it's all going to be hand powered.
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Ok so wait are you talking about hooking up the pump to your steering wheel and providing pressure with your arms?

:confused:

Thats way it reads to me
 
I'd thought about all electric but I'm not sure what a good choice of actuator would be, no idea what kind of force is needed. The electric/hydro setup like jack edwards uses is $$$$
 
Ya when you said Gear pump I made a bunch of assumptions and skipped to how to mount an a/c gear pump on the end of a camshaft with a drive shaft/shear section.:rolleyes:
 
larboc said:
Yes, that's the way typical marine hydraulic steering works. It's "manual" hydraulic steering.

like this:
https://www.westmarine.com/buy/seast...19?recordNum=1
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Did not know that.


But I don't think your gonna achieve the pressures if any out of power steering pump. nor would it work like you said,, without a selector valve..


There was a article there on west marine that talked about what the pump is, being a swash plate piston pump..

The only thing I can think of that would be close to that and not be for boat steering would be a travel motor but it wouldnt be worth it


You could use a package hydraulic system, like for a dump bed, a exciter ring a hall effect sensor and a arduino board.

Or a package system...a optical encoder (2 maybe) and a arduino board to control your positioning
 
I vote you’ll be fine as long as you buy a new pump. Only issue I see is you will have to use a cylinder the moves back and forth on a rod or 2 normal rams. You need to have equal volume of oil moving for both the left and right turn.
 
ThePanzerFuhrer said:
I vote you’ll be fine as long as you buy a new pump. Only issue I see is you will have to use a cylinder the moves back and forth on a rod or 2 normal rams. You need to have equal volume of oil moving for both the left and right turn.
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Surplus center has 2" bore steering cylinders for not a bad price that I was looking at.

This whole discussion has me thinking more seriously about abandoning hydraulics all together and going drive by wire with a linear actuator setup as a servo. The concept is pretty easy and would make a homemade autopilot system really easy.

If this was for kicker steering I would be more excited about experimenting a little more but I don't want to get too electronically complicated on the main steering for the boat.
 
larboc said:
Surplus center has 2" bore steering cylinders for not a bad price that I was looking at.

This whole discussion has me thinking more seriously about abandoning hydraulics all together and going drive by wire with a linear actuator setup as a servo. The concept is pretty easy and would make a homemade autopilot system really easy.

If this was for kicker steering I would be more excited about experimenting a little more but I don't want to get too electronically complicated on the main steering for the boat.
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Get the pair of rams (or single ram made for steering), stick an appropriately sized wheel motor at the helm and crank away. There's no reason it shouldn't work. I can see using a gear pump instead of a hydraulic motor potentially having weird characteristics if it wasn't meant to spin both ways but a gear motor meant to spin both ways should be fine.
 
Either just use electric rack and pinion out of any modern shitbox or, run a drift bag for trolling, it will let you idle the motor up a bit and keep the engine cooler and give you a ton more control over direction. Run one on each side on windy days. Tie the rear off to the back of the boat so the bag doesn't wander too far out. Don't forget they are there when it's time to go home!
https://www.ebay.com/i/132811766364?...waAvB_EALw_wcB

ETA: I've trolled a half million miles with them fishing Lake Ontario and Lake Champlain for Salmon.
They really help keep the bow down too in rough weather.
 
larboc said:
I'd thought about all electric but I'm not sure what a good choice of actuator would be, no idea what kind of force is needed. The electric/hydro setup like jack edwards uses is $$$$
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I'd just adapt a 12V motor to the steering wheel using a belt.
then use an ardupilot box to control it using a brushed ESC
 
87manche said:
I'd just adapt a 12V motor to the steering wheel using a belt.
then use an ardupilot box to control it using a brushed ESC
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Because there's no chance of that being a PITA to make reliable in a marine environment. :shaking:
 
This discussion is way over my head but what about just using a forklift orbital valve and cheapo ram? No idea how you would bleed the system but I assume it would work.
 
$50 seems reasonable.
https://www.alibaba.com/product-deta...28976fc1cpueqC

$70 for all the electronics
https://www.ebay.com/itm/ArduPilot-A...8AAOSwQZFdto9D

plus the cost of whatever it takes to belt drive the wheel.
use a tupperware container to keep the APM dry.


so probably under $200 and you now have full autpilot and waypoint steering from your cell phone in your boat.

then you can get real fancy and add sonar to it, so you can see that data on your phone too.
https://ardupilot.org/copter/docs/co...ar-analog.html
and setup a depth fail safe so it can't drive you aground if you're not paying attention, because now you have autppilot.
:flipoff2:
 
Wouldn't the autopilot setup require powered hydraulic steering? Maybe the wacky electrical idea isn't too bad. Except for when your shitbox breaks and you have to be towed in without steering.
 
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