Hydraulic circuit add

[agjones]

Ok, so this is for a small excavator, but my tractor people here know more than most... So please help if you're in the know...

Got an ancient great condition yanmar excavator and need to add 2 cylinder functions.

I could use solenoid diverters and steal the flow from the little used swing cylinder... But it uses a not very precise to control floor pedal.

My question is this: can I instead, steal flow between the pump (a triple) and the main control valve using a priority flow divider w relief to tank (excess to the main control valve), then add joystick buttons and solenoid actuator?

That'd give me better control but does pinching 6gpm from the 3/4" source cause probs down stream?

The attachment shows the pump and its 3 pressure feeds all going to different ports on the main control valve. Drive, cylinders and make-up it appears to me.

 

[rScotty]

Probably the easiest way to power a couple of additional two-way cylinders independently is to buy a standard two spool open center FEL control valve that has a Power Beyond (PB) port. Use its 4 workports to power your two cylinders. If you aren't using those extra cylinders, the flow just passes through to wherever it was going. Don't forget to order the PB conversion plug/sleeve.

To install it , first select one of your pressure hoses and have two hoses made up that same total length. Plumb the pressure side from the hydraulic pump into the IN port of the new control valve. Then from the PB port on to wherever the hose you've interrupted was going originally.

The 4 work ports on top will provide power for your two cylinders.
You will also need another return line from this new valve to the sump, or it can be spliced into one of the existing return lines.

Have the hoses made to match the threads of your fittings. Ask to have the relief valve set to match your system.
Get the smallest (0-10 gpm) capacity loader control valve you can find. 6 gpm and under are rare.

Here is a typical good quality FEL control valve that would work. Other places have them for less, but in valves you definitely get what you pay for.

Wolverine by Prince Mfg | Brands | www.surpluscenter.com

Wolverine by Prince Mfg,Brands, 1.5x4x1 DOUBLE-ACTING HYDRAULIC CYLINDER WOLVERINE WWXT1504-S Brand new. WOLVERINE by PRINCE welded, double-acting

www.surpluscenter.com

For a better diagram go here:

https://www.surpluscenter.com/_MoreSpecs/iPrinceMBValves.pdf

Luck,
rScotty

 

[agjones]

Thanks for thinking through it and responding .

That setup would be simpler for sure, but would leave me with more levers. I'd like these two functions on buttons to replicate standard-ish controls. I guess it also leaves the control valve with no flow (for cylinders) when actuated.

I have a trigger on this new stick too so maybe use it to fire a diverter solenoid to a priority valve (I've got a little budget to modify but not enough to buy a more modern machine).... That way, I'm only stealing flow when needed. And still have flow to move the other cylinders when my circuit is active.

And when all my solenoids inevitably fail.... everything original still works.

This machine is super basic yanmar, yb401w, great example of solid Japanese quality.

 

[oldnslo]

Do you know what each pump section operates now? Would one of these not be used when operating the functions you want add.

You can purchase solenoid operation valves with power beyond capability but they are on / off with no metering so all of the flow will go to that function.

Style of valves being added kind of depends on what you want them to do and how you want them to operate.

Examples of grapple control:
Some people add a solenoid operated diverter valve to curl/ dump to operate a grapple this allows press of a button and same function that used to control curl / dump now controls grapple. This provides fine control but you can’t operate grapple and dump at the same time.

Others put a 3rd valve that is solenoid operated in power beyond loop to run grapple. This is on off with no feathering of grapple.

Both styles work just a preference on the owner wants it to work.

 

[rScotty]

Thanks for thinking through it and responding .

That setup would be simpler for sure, but would leave me with more levers. I'd like these two functions on buttons to replicate standard-ish controls. I guess it also leaves the control valve with no flow (for cylinders) when actuated.

I have a trigger on this new stick too so maybe use it to fire a diverter solenoid to a priority valve (I've got a little budget to modify but not enough to buy a more modern machine).... That way, I'm only stealing flow when needed. And still have flow to move the other cylinders when my circuit is active.

And when all my solenoids inevitably fail.... everything original still works.

This machine is super basic yanmar, yb401w, great example of solid Japanese quality.

Well, not much to add. You seem too have thought it through. I don't see why your solenoid to a priority valve wouldn't work. It certainly would not be crudely controlled, so my guess is you would just power it until what? a relief valve going off?

Using a solenoid to turn on an adjustable Flow Control valve is another option. In function an Flow Control valve is much like a Power Beyond coupled with an adjustable diversion outlet. Mostly used for motor circuits, but the solenoid would let it work as a crude cylinder control circuit. Same control problem as the your priority idea, but allows for more variation in proportion.

I don't see any problem with stealing 6gpm through a 3/4" source. That is in the range of household water flow.

Gotta agree on Yanmars. Their reliability is legendary. I've wondered how much of their priority on quality has to do with Yanmars sheer size and diversity, and how much is due to their company structure. How does being a privately held firm run by generations of an extended family stack up against the US type of publically-owned corporation. I'm not sure the US even has anything similar domestically - not in large scale manufacturing anyway.

rScotty

 

[agjones]

I've had great experiences with Kubota and yanmar, idk what their sauce is cousin power maybe? Wouldn't work worth my fam

I appreciate you putting some thought to it.

I could power the diverter indefinitely since there's a path back to tank and everything else gets flow... Just a little less. This priority valve has it's own relief.

I'm sure I missed something, but this is why we're messing with a low stakes machine not an under warranty daily use one.

I've got everything set to install and run using the foot pedal and flow from the swing cylinder. Assuming that works well, no reason it wouldn't, then I'll test adding solenoid divider upstream of the main valve and see if I even notice the pinched gpm.

If not, I'll leave that alone. Seems the worst thing might be a little slower movement at the boom.

 

[agjones]

Do you know what each pump section operates now? Would one of these not be used when operating the functions you want add.

You can purchase solenoid operation valves with power beyond capability but they are on / off with no metering so all of the flow will go to that function.

Style of valves being added kind of depends on what you want them to do and how you want them to operate.

Examples of grapple control:
Some people add a solenoid operated diverter valve to curl/ dump to operate a grapple this allows press of a button and same function that used to control curl / dump now controls grapple. This provides fine control but you can’t operate grapple and dump at the same time.

Others put a 3rd valve that is solenoid operated in power beyond loop to run grapple. This is on off with no feathering of grapple.

Both styles work just a preference on the owner wants it to work.

Thanks for chiming in, always appreciate the input. By the looks of it, the first pump is the transmission, steering & drive. the second is all the cylinder functions, third looks to just be makeup flow.

I'm going to tackle this in two parts. 1-diverters on the swing cylinder flow when working properly...2 - flow divider up steam -->solenoid actuator -->the prior diverters.

I'll put two diverters down steam of the original control valve and setup buttons to control them. 3 functions... One at a time.

If that works, and I hate using the clumsy foot pedal as much as I expect to, I'm considering adding a flow divider and double acting solenoid actuator up stream of the original control valve. Then take my two downstream diverters from earlier and pipe them from this new actuator with it's own flow.

That should leave me with original function restored minus some flow and my new circuit's two functions on Independent flow controlled by joystick buttons.

I won't get proportional control on the cheap 12v actuator... But it's smoother than a diverter.

Between TBN, Surplus Center and making up our own hoses this isn't as expensive as it sounds. This machine is easy access for routing etc.

I'll post an update ASAP.

 

[oldnslo]

You may already know this but If adding valves upstream of existing make sure you have a relief valve either before or in the new valves to protect the pump. On flow dividers if you block flow on one leg it may block flow on both legs

With priority flow control blocking controlled flow may also block excess flow

Flow diverter may or may not operate a double acting cylinder they are not directional valves.