@baraki how inexpensive is your proportional valve totally costing?
About 550Euro complete with plate and compensator.
Ok, I think around €160 including 6 way valve and pressure switches but excluding motor.
Although interested in the resent bang-bang valve developments!
Does this scheme will work?
Just put pressure transducer between valve’s T and orbitrol’s P for disengage signal.
I think you must put à relief valve (pressure limitation) at the input of the électro valve in case the cylindrer is full right or left
I think there is one in orbitrol but not in pump
It his better to reverse orbitrol and valve to get priority to orbitrol
Like @Francois say: a relief same a orbitrol setting need to be put after pump
(the relief of orbitol in this way cannot works in some condition .)
You put one sensor on orbitrol/sterring unit to detect rotation and you use on the software “turn sensor” .
check this : encoder discussion
It will work if the orbitrol is not of the OC type and does not start turning the steering wheel after applying pressure to the actuator.
Another problem is the solenoid valve slider type. This type with the P to T connection in the neutral position has too little precision to control the steering wheel. You will not be able to adjust the PWM to guide you well.
Any fault with the valve and you’ve got no steering.
I updated @d1ken scheme. Does this scheme will be working propely? The biggest issue I think is good proporcional valve. Any ideas ?
no, with check valves how does the oil return to the orbitol from the steer cylinder in manual use?
The problem is the two check valves you have put on the line from orbitrol to steer cylinder.
You could use a double piloted check calve there.
Your pressure sensor would not work because you don´t have a 6/2 valve to block connection between orbitrol and steer cylinder/proportional valve.
The sensor works, take a good look. The problem is that only once …
Oh I see, oil would be trapped behind the check valves before the pressure sensor
So a small leak from sensor to tank would solve the problem.
But why not just use a cheap proximity sensor to count some teeth on the steering wheel, now that it is possible to turn it easily. (Not stuck like when using a 6/2 valve.)
I updated the first scheme according to advices and I sketched another option. Second options for me is the same as first. What a difference between double pilot check valve and 6/2 valve ? How can I get sginal to 6/2 valve ? I need on/off output signal from autosteer pcb.
Your updated first drawing should work now. And you could also use the encoder option in drawing one.
Drawing two will work too, but encoder is not good there, because your steering wheel is blocked when 6/2 valve is activated. Here you should put in your pressure switch from drawing one.
There are already some threads about connecting 6/2 valve to PCB.
See steer.png in support folder (on github together with AOG program)
Depending on which motor driver you choose, it is dir or pwm2 that sends signal to relay for 6/2 valve.
Any hydraulic experts care to cast an eye over my idea?
I’ve got an open centre tractor which I would like to use my standard Hydraforce valves with.
I was thinking a sequencing valve and a check valve could be used to create a 50 or 75 bar spur (red) to the main circuit, to which I could then directly attach my usual valves. Similar to the fluid-system concept but the open-centre addition should cost less than £100
I use a open centre system like this and it’s working good:
Only other part that’s not in the picture is a relief valve in LS line set lower than the main relief valve.
Theoretically, it might work. In practice, it may not steer smoothly. Prop. would start to open with 75 bars to start. This is a big pressure difference, it will jerk. I use compensators thanks to which I have a delta of no more than 6 - 8 bar and then it is ok. The smaller the pressure difference, the more accurately you can control.
A priority valve or a 3-way compensator will definitely be a better solution.
What is the availability for example EC12-42 80psi (like Baraki is saying, replace valve A in your drawing)
That’s exactly what I’ve been looking for! Thanks guys
I spoke to a hydraulic supplier today who gave the classic ‘can’t be done’ attitude when I asked him about priority valves. Hence I was looking at the wrong end of the valve range.
I’m also surprised how low your pressures are. My setups on CCLS systems seem to work well at full system pressure.
I’ll see if I can find a non-hydraforce version as the lead times are ridiculous, as usual with HF.