Hydraulics help please

I have a 90 something Honda H5013 4wd tractor. It's a small tractor
as tractors go but it is a real workhorse. Anyway, it has a 4 foot
dozer blade that has 3 positions, left, right, and center. I would
love to be able to swivel the blade using hydraulics, because then the
angle would then be whatever I want and I wouldn't need to get off the
tractor to adjust the thing.
So I started thinking about getting power from the tractor
hydraulics and it would just plain be better and easier to have a
separate hydraulic system for the front blade.
I think a power steering pump with built in reservoir would be
perfect. If it will work.
The rotation of the pump and the front PTO shaft would need to be
the same as would the RPM, which is 2650 tops on the Honda.
I want to use a double acting cylinder. And I think an open center
valve the type of valve that should be used but I don't know. The
valve must allow the hydraulic fluid to flow back to the pump when the
spool is centered while at the same time holding the cylinder in
position.
One advantage of using the front PTO is that it is easily engaged
and disengaged so that the pump won't need to run all the time. The
PTO can be engaged or disengaged at any time just by moving a lever.
Has anyone here done this? Do power steering pumps spin as fast as
2600 RPM? I think the one in my Toyota truck does. Is an open center
valve the right one?
Thanks,
Eric
Reply to
etpm
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I doubt that 2600 rpm would be a problem. The older vehicles I've had would spin faster than that.
Something else to consider would be using an actuator. Something like this:
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Johnny Buckets used to use something similar for lifting their add-on buckets.
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Reply to
Leon Fisk
There are all kinds of hydraulic valves, you need an open-center valve that holds the load, that should be a standard type.
The double-acting cylinder displaces different amounts of oil when the rod is in or out, you need to have a supply reservoir able to hold at least that much fluid. Also, you need a pressure relief valve, although most power steering pumps will have that built in.
Jon
Reply to
Jon Elson
Thanks Jon. I was looking at the tractor just after posting the first message and thinking about the double acting cylinder pressure difference but not the volume difference. Now I'm thinking that two single acting cylinders would be better. There is room for two cylinders I imagine the valving would be the same as for just one double acting cylinder. Eric
Reply to
etpm

Using 2 double acting cyls solves the first problem - or even just 2 single acting cyls.
Reply to
Clare Snyder
Correct on both counts.
Reply to
Clare Snyder
I used single acting porta-power type cylinders for the boom and bucket lifts on the loader I built for my garden tractor, since they allowed the bucket to follow the ground when clearing snow. I simply plumbed the second ports of both valve sections to a manifold in the return line.
Snow plows use two single-acting cylinders to swing the blade. You could look at their service manuals for the valving.
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I had to figure out how to repair and install one that had been crudely ripped out of the old truck.
Reply to
Jim Wilkins
Hydraulics for a blade have to have a large steering piston cylinder. Run one forward and one backwards and you have push pull on the blade.
Won't you need thousands of pounds on that cylinder ?
I have a Grapper that has 6000 psi crushing power. Something like those pistons would be needed. The cylinders are large.
Martin
Reply to
Martin Eastburn
The usual continuous force on the blade is the drawbar pull of the tractor. I had to put on ag tires with chains to have enough traction to plow on worst case snow and ice, so their traction on solid dry ground became the maximum, instead of traction of rubber on asphalt.
I sized the cylinder geometry for 1000 PSI oil pressure but the frame for at least 2500 per side. When I turned it up to 1600 PSI to get unstuck from a snowbank the front tires blew. I think the front axles would have gone next. The extra front wheel loading also damaged the steering sector gear and I had to machine a new one.
The control valve came with a fixed overpressure relief. I made an adjustable replacement and added a gauge to monitor it.
I designed my bucket loader for the ground-level impact that would raise the rear wheels, and it suvived one such hit on a stone step with only a slightly bent pivot pin, which was the only significant structural wear after 3 winters of fairly hard use. The PTO to pump belt drive was more of a problem.
When you hit something the hydraulic pressure can spike very high because the centered control valve isolates the impacted cylinder from the pump pressure relief valve. On my loader the lowered bucket rests against wood crush blocks on a stronger front bumper. Some commercial plow blades have a spring-loaded lower edge.
-jsw
Reply to
Jim Wilkins
It's only a 1000 lb tractor. Plus or minus some possibly added weights. See:
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Reply to
Leon Fisk
I went to Northern for the hydraulic parts I couldn't find cheap locally, then to Bailey when Northern reduced their selections. The local Parker Store is competitive on small fittings.
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Reply to
Jim Wilkins
On Sun, 30 Sep 2018 10:57:29 -0400, Fake Gunner forged:
That's true.
At idle with the steering wheel static, a typical power steering pump holds about 80 to 125 psi in the output line. Yank the steering wheel a couple of times in rapid succession -- causing the pressure-release valve to flutter open and shut -- and a typical modern pump might momentarily put between 1,000 and 1,500 psi through the lines. Older and lower-performing pumps might run 850 psi of momentary pressure or less, while heavy-duty off-road pumps may sustain 1,600 or more. High-performance pumps can jump to 2,500 psi before the valve releases. and hold upward of 8,000 to 10,000 psi internally before bursting.
But that's nothing compared to the sucking power Rudy and his pal Fake Gunner can produce, once they get on their knees and get down to business.
Reply to
Klaus Schadenfreude
The 8 foot Frink on my old Ramcharger ised 2 cyls of less than 2 inches diameter. Depends on the geometry how much force you need. If the cyl has 1 foot of movement it takes half the forcr it takes if the cyl only has 6 inches of movement to turn the blade the same amount.
I could "walk" the truck out of some pretty deep snow using only the blade turnong cyls and a shovel.
Reply to
Clare Snyder
The blade really doesn't need much force to turn it. It is meant to be elevated and then a pin is pulled by hand and the blade is swiveled about a pivot and then the pin is put back in place. To resist the force against the blade though is different. I think that a valve that holds the cylinder in position will be able to resist any force the tractor will be able achieve. So I'm thinking a 1.25 cylinder with a 5/8" or 3/4" rod will work fine. The power steering pump will be able to provide just over 1000 PSI. Coupled with a 1.25" piston the pushing force will be about 1220 pounds. Eric
Reply to
etpm
Not at all. If it has a pin it is MANUALLY adjusted. Hydraulic blade has NO PIN. I've worked on plenty of them - on both tractors and trucks - both manual and hydraulic. What good is a hydraulic unit if you can't adjust it without leaving the driver's seat?????
Reply to
Clare Snyder
Ok then why use Cylinders in the first place. Just raise rotate and pin. If you don't want to move it on the move then just forget everything and use a pin. If you are pushing a load with the blade, and you only have a Cylinder it needs to be as large as you risk the tractor.
I don't get the unpin - turn the blade in an arc then pin and drive. You have to get off the tractor at least once. Martin
Reply to
Martin Eastburn
Power steering pumps "generally" turn at close to crankshaft speed, as the pulley on the pump is close to, but slightly smaller than, the same size as the crank pulley. On your "average" V6 or V8 that redlines somewhere north of 4500 RPM (and some WELL north of that figure) the pump will definitely be turning above 3600 RPM fairly often. Maximum flow and pressure ratings are often given at 5000 shaft RPM A GM Vickers style vane pump runs about 2 gallons per minute ans 1250-1400psi in normal PS use and can apparently go as high as 9GPM at higher speeds.
Reply to
Clare Snyder
If you are concerned about contaminating the Honda's hydraulic fluid you could put a filter like this in your return line. They are smaller than spin-on filters and can be installed in the line without a support bracket.
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Reply to
Jim Wilkins
Greetings Clare, Somehow the issue is getting confused. The blade is manual. I want to put hydraulics on it. So that I don't have to get off of the tractor to swivel the blade. Speaking with a neighbor about this he mentioned that he has a GM pump, the kind I want to use because of the integral rteservoir. He said it sping CW. Which is perfect because facing the front PTO shaft it spins CCW. Now all I gotta do is find two cheap cylinders that have at least a 1.125 bore and 6 inches travel. I think a 5/8" rod would be fine. I can use double acting or single acting. Eric
Reply to
etpm
You're not getting it Martin. The whole reason is so I don't have to get off the tractor like I do now. I even said that in my first post. Just look above in the first paragraph. The last sentence. Eric
Reply to
etpm

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