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Hydraulic solenoid valve block


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Does anyone here have experience of hydraulicvalve blocks controlled with solenoids? I would like to convert my older digger with manual controls to joysticks, at least in my head!

 

Of course there will be an argument not to, and that will probably be the ned of tonights crazy plan, but is this doable?

Edited by rusty_wingnut
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From "piano" to "joysticks"...

Several ways to do it but I think it is less expensive and complicated to sell yours and by a new type as it is a lot of work.

Perhaps a accident write off digger can get you the parts but it will not be easy..

Do-able, but complicated.

 

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I think you are confusing solenoids with pilot control.

 

for a solenoid block you want an old hedge cutter but this will have zero feel for digging with and be very rough to operate.

 

Buy a newer digger! or re bush your levers.

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You can't replace the cable or lever operated valves on your digger with simple solenoid control valves. Normal solenoid vales are either open or closed and that will make operation of your digger impossibly jerky. If you convert to electric control you will need proportional valves which require a variable current to move the valve to any position between open and closed.

Decent quality proportional valves cost hundreds of pounds each, and you also need a lump of fairly fancy electronics to drive each coil (and there are usually two on each valve). Having said that,  the electronics does not need to be costly. When I made the variable speed control for my hydraulic winch, I used a pair of PWM motor control modules I bought on e-bay for about £10 each.

Actually, there are ways of reducing the jerkiness of simple solenoid controls with flow restrictors, sequence valves and other fancy bits and pieces, but the hydraulic circuit rapidly gets seriously complicated and needs a fair dose of black magic to make it work properly.

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Quote

You can't replace the cable or lever operated valves on your digger with simple solenoid control valves.

True

Quote

Decent quality proportional valves cost hundreds of pounds each

Thousands! - we use a lot of them.

 

The best option I've found for this is to use regular lever oerated spool valves.  Remove the internal (return to centre) springs and move the spool with RC Servos.  (You can leave the springs in place and use bigger servos).

This gives a reasonable proportional valve.  The only issue with it, if you're trying to achieve tight, closed loop control (I suspect you're not trying to achieve closed loop at all) is there is a wide 'dead band' in the middle of the spools movement.  When you are reversing direction, this gives a lttle jerk / discontinuity.  You can tune out most of the effect of it - but it's still noticable.

(Yes, I have tried & used this method, before you ask)

In your case, the dead band will in fact make it easier to control manually.  Using RC Servos has the added bonus that you could make your digger radio controlled - which would be even cooler than just joystick operated from the cab.

Valves from FlowFit & the like are pretty low cost and fit the bill.

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That sounds like a great idea! My first thought was also that getting the necessary proportionate control would make it very expensive.

@elbekko you fancy fitting RC servos to our skid steer? Sounds like a fun challenge! :hysterical:

 

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20180808_100847.thumb.jpg.85f6edaaa8f7bebdf6a8a056557a579c.jpg

Another option, if you need (ish) closed loop control, is to use Orbitrol (steering) valves.  You can turn the valve with an RC Servo - then it gives you reasonably accurate positional control.  Good enough for RC steering on full size vehicles anyway. 

I was going to use this on a job to make a line of 360 Diggers repeat the same movement over and over again.  We had oil drums attached to the digger arms, using them as a giant wave machine.  (sadly) it was cheaper to employ drivers than modify all the diggers!

Si

 

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