Hydraulic control

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Geochurchi
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Hydraulic control

Post by Geochurchi »

Hi All, we are trying to get smoother control of our hydraulic fluid that drives the trucks on our locomotive, right now the valve is a handle that rotates right or left depending on which direction we want to go, throttle is fixed at one speed.
Looking for suggestions.
EBFD6F52-3A63-44EB-9ED2-3A831E619B39.jpeg
If it ain’t broken keep working on it until it is .
Geo 🇺🇸
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Bill Shields
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Re: Hydraulic control

Post by Bill Shields »

There are sliding piston directional control valves that are specifically designed for throttling

Going to mean a lot of piping and linkage rework.
Too many things going on to bother listing them.
STRR
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Re: Hydraulic control

Post by STRR »

In the past, I have used a "slushing" valve. More appropriately called a variable bypass valve. This was not on a locomotive. Some time ago and probably on a different board, there were conversations about this. When the valve is shut, all the hydraulic oil is bypassed through/past the valve. As you open the valve, less oil is bypassed and more directed to the hydraulic motors. This continues as you open the valve until 100% is going to the motors and nothing is being bypassed.

Darrel Klompmaker of little A-Merrick-A developed a slushing valve that allows true free wheeling of the locomotive & train. He might be the best person to contact for more information and advice.

Good Luck,
Terry
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Bill Shields
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Re: Hydraulic control

Post by Bill Shields »

The bypass idea is standard industrial technique.

Question is then how to reverse?

Most of the locos I have seen operated use a little back throttle for braking..
Too many things going on to bother listing them.
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warmstrong1955
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Re: Hydraulic control

Post by warmstrong1955 »

The control levers provided by valve manufacturers offer little control, and are more an 'on-off' type of control. 'Tapered', or 'Sliding' spool directional valves, with a longer stroke and better metering abilities are spendy.

Best thing you can do, is design your own, with the centerline of the spool, closer to the centerline of the lever pivot point. The idea being, to increase the stroke of the lever in relationship to the stroke of the spool. Also, add a hand rest.

See attached. This is a V-20 Gresen steering valve control for an ST6C LHD, which is basically an 6 cu/yd underground rubber tired loader. This design, or similar, was used in almost all the 6 yd3 and smaller loaders, as well as the 26 ton and smaller trucks. Larger equipment used pilot-op systems.

The end of the standard issue handle from Gresen moves about 1-1/2" from the neutral position, either way. The one in the pic which we manufactured, about the same length as the Gresen handle, but moves about 4" off of center either way. It gives the operator the ability to feather the steering, and also reduces the effort required to move the handle.
Note also, the hand rest, so you can plant the heel of your hand somewhere, while you operate the lever with your index finger and thumb. This gives you more control, and also prevents the herky-jerky movement you get when the machine starts moving.

Bill
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ChipsAhoy
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Re: Hydraulic control

Post by ChipsAhoy »

I wiil pm you a sketch of how to modify a spool piece in a specific valve. It is a technique designed by two fellows other than me. Works Perfect. Maybe Jack from ALS can chime in on how well it works for him.
It will be about a week before I send it, I am off at a train meet away from home right now!
Scotty
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Steggy
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Re: Hydraulic control

Post by Steggy »

Geochurchi wrote: Wed Jun 01, 2022 3:48 pm Hi All, we are trying to get smoother control of our hydraulic fluid that drives the trucks on our locomotive, right now the valve is a handle that rotates right or left depending on which direction we want to go, throttle is fixed at one speed.
Looking for suggestions.
EBFD6F52-3A63-44EB-9ED2-3A831E619B39.jpeg

I recommend you work out how to get proportional engine throttle control. A fixed and fairly high engine RPM setting will almost always produce lurching.
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Geochurchi
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Re: Hydraulic control

Post by Geochurchi »

Thanks Scotty.
If it ain’t broken keep working on it until it is .
Geo 🇺🇸
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makinsmoke
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Re: Hydraulic control

Post by makinsmoke »

Several manufacturers over the years have sold gas/hydraulic locomotives with a couple of different valves .

Both offer proportional speed control, center stop, and reverse as the valve/lever is reversed past neutral.

No need to reinvent the wheel.
Geochurchi
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Re: Hydraulic control

Post by Geochurchi »

Makinsmoke, that’s what we have but it’s not a smooth operation, maybe the valve needs to be rebuilt or replaced. Do you have any particular valve in mind?
If it ain’t broken keep working on it until it is .
Geo 🇺🇸
Pontiacguy1
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Re: Hydraulic control

Post by Pontiacguy1 »

Our club locomotive is an F7 with a powered single-truck engineer's car. Was built by E&S in Florida. 16 HP V-twin with a very powerful hydraulic drive system. Uses the same type of valve to control forward/reverse and speed as what you have. It is notoriously temperamental when trying to start/stop or ease into something. It takes a very light touch or it will suddenly load and lurch or try to slam to a stop very quickly. Sound familiar?

It is still this way, although annoying, it is very robust and works. I have found that for myself, the best way to operate it is by ear. If you are rotating the valve, when you hear the hydraulic whine change, then stop rotating the valve. It will start to move in the direction desired in a nice smooth motion. Most people turn it until they can feel it start moving, then it moves very quickly.

Whatever solution you find, I'm sure that others with the same system would be interested, especially if it is something that can be done without having to re-plumb the whole locomotive.
Geochurchi
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Re: Hydraulic control

Post by Geochurchi »

That’s it exactly it, it’s a learning curve, we have 3 Loco’s and they are all a bit different, there must be a better way, I will keep looking and asking questions, definitely don’t want to do a lot of replumbing either.
If it ain’t broken keep working on it until it is .
Geo 🇺🇸
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