First smoke today. The Danfoss valve seems to be working as expected, LS line goes through the valve to priority valve. Put an adjustable pressure switch in the Orbi LS line, that’s still to be tested.
Hi
Last week I tested my Hydrafore SP10-57C spool on my Valtra and the pressure didn’t return near to 0, it stayed at 1000 psi in neutral.
So I think on Valtras the LS line as to be able to drain somehow trough the side of the valve.
The SP10-58D with a dual piloted check valve works right but the SP10-57C without check valve seamed to be smoother. So I will order a SP10-58C for testing.
@nut that’s a nice setup!
But doesn’t the ls system have a preset minimum pressure a lot higher than 0 psi?
The standby pressure is near from 0, under 200 psi for sure. In the Valtra service manual I think it say 7Bar ( 101 psi) I use a 0-3000 psi gauge so it’s not precise at very low pressure. I just used the SP10-57C for a few minutes but the pressure increased to 1000 psi as soon as the wheel didn’t move and I could hear the engine working harder than usual.
The pressure lowered to normal pressure when moving the wheels (300 to 800 psi) with the valve or steering wheel but raised just after.
I think @baraki explained it very well and this is what is happening on my Valtra
I think the easiest cure is to put a T-piece into the LS line with a small orifice to tank, something like 0.3 mm to allow the LS line pressure to release, of course there will be a little flow loss but I think this is the way it’s done mostly on LS systems in any case.
Re-checked the spool diagram and on my setup it vents the LS line to tank, so it’s the correct type for this kind of system.
Hi,
I believe that it is clear that there must be some kind of bleeding of the LS signal to the tank(otherwise pressure build up in the whole brake/steering part due to the “LS” piloting the priority. Here it is how it is mounted for 2 years on my valtra 8050 and T serie 3. The only difference is that it is mounted with the shuttle valve on the T3 serie instead of the regular “T” connector. I hope the drawing is clear enough!
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I don´t think the drawing is clear enough.
If there are a shuttle valve, how should the oil be able to pass through the bleeding valve towards the orbitrol?
I would believe the shuttle valve can only allow pressure/flow towards the LS input on the pump.
And is the orbitrol LS line open to tank when not active?
Well it must be otherwise you could not notise any difference with or without the bleeding valve on the Valtra 8050 (open or closed bleeding adjust screw)
Edit: I think i missed that LS on your diagram must be LS from priority valve, and maybe therefore bleeding normally goes through orbitrol.
Yes, Larsvest. I installed cetop valves on the valtra. In this tractor, the pressure from the Ls escapes via the orbitrol in the neutral position. I did not use a 2/3 valve for shut-off, but it was necessary to install a double controlled check valve (lock) on the L, R line after the shuttle valve + a throttle check valve on the LS line of the orbitrol. And everything works fine.
Recently, I have been going towards the cetop plates with a lock and a swing valve, or actually a compensating valve with an LS output, and adding my own connection block so that everything is fully integrated.
The easiest solution is not to use the 57C but 58C or any other valve that bleeds the LS to tank when neutral. No additional bleeds etc. needed.
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Discharging Ls from the proportional valve side is not a problem. You have to solve the LS retraction lock to the orbitrol when it is proportional and the unlocking when using the orbitrol. The most elegant solution would be a pressure controlled diverter valve from a propo valve.
What do you mean by retraction lock? Releasing pressure when in autosteer mode? I have it now set up with only the shuttle valve in the LS line and nothing else and seems to work OK. Needed to add deadband to the arduino code so that the spool is allowed to return to zero so it actually bleeds the LS line, before that it was keeping the LS pressurised all the time as the spool was never in the nneutral position (expect when steer error exactly zero)
Yes. You are right, there is no problem with the 58c valve. I was thinking wrong.
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Could you make a schematic ? not sure to understand very well how it is all piped together… Thk
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Hi
An update with my Hydraforce valve setup.
It works fine but at the engine start the front wheels move a couple centimeter always to the same side. Changed the A/B line on the valve and the side changed so there must be something with the valve.
I can not figure out the origin of this behaviour.
It’s not a big deal but probably enough to check for other valve for my next setup.
Phidgets motor spins for a second every time I power up. Can’t remember my hydraforce setups had done the same, or haven’t just noticed.
If you remove the current (disconnect the electric part of it ?) => if it solve, consider installing a switch to cut it off, so no danger on the road (of the field).
I checked today with no electrical connections on the coil. Still the same wheel movement at startup.
Definitively an hydraulic issue. Oil is coming out (pushed out) from port 2.
It seam to be just a little movement when the pressure is building up in the whole system.
The spool is probably not in the center position when engine off?
Or maybe some internal leakage, it’s an old tractor (over 10 000h)
It’s an SP10-58D with dual piloted check valve.
I think I will check with LS disconnected.
Are you sure the cause is a proportional valve and not an orbitrol?
I switched the lines just after the look valve and the steering direction changed so I think it is from the proportional valve.
Valve installed in May, I first noticed this in august. I am (almost) sure there were no movement before valve installation.
Maybe the double check valve is the problem. (Broken spring, steel balls or slider not seating correctly)
Or substitute the check valve, with a 6/2 valve and eliminate the problem.