Improve input controls on excavator?!

   / Improve input controls on excavator?! #1  

MaxG

New member
Joined
Feb 28, 2024
Messages
12
Location
Queensland, Australia
Tractor
DongFeng 30HP Tractor, Shandong Noute 2.5t Excavator
I bought an excavator to do some land management (stumps, lantana, clean-ups). It's a self-imported electric 2.5t excavator from China.
I am happy with it in principle. However, the controls are shocking. I can nicely operate the boom and stick on my back-hoe, but these controls are jerky, not allowing for precision work. E.g., one of my prime movements is scraping, that is running the bucket or rake parallel to the ground, which seems impossible to achieve with this machine.

Long story short: Can these controls be improved? (for a reasonable price)

I read a few posts on this forum; this one talks about wire-controlled valves... which I have on the FEL on the tractor, and which allow for fine control.
I have not much of an idea of valves and hydraulic parts, as I never had to deal with it (as in diving into design details; other than replacing the odd hose on the tractor).
However, I can work with electronics. (Meaning, if there is cost-effective to use servo controlled valves via joystick input?)

Are there specific servo valves, or other types I need to look at.
In the quoted post it is also talked about a flow restrictor (means most likely a flow control valve).

Any hints appreciated. E.g. cost, complexity, best approach?!
 
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   / Improve input controls on excavator?! #2  
I’m assuming by the profile picture that it’s a Chinese excavator. Every video that I’ve seen of those are super jerky. Cheap valve body’s are jerky. Flow restrictions might help but there’s not much else to do. A quality valve bank would cost more than the excavator.
 
   / Improve input controls on excavator?!
  • Thread Starter
#3  
I’m assuming by the profile picture that it’s a Chinese excavator. Every video that I’ve seen of those are super jerky. Cheap valve body’s are jerky. Flow restrictions might help but there’s not much else to do. A quality valve bank would cost more than the excavat
Hmm, do you mind explaining this a bit more?

Is the issue the 'valve bank' or is it the control (valves). I have valves in the controls (as far as I can tell; see photo of the underside of the control stick). Not sure, if these operate the (real) valves or not. Or are the joystick valves it?
 

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   / Improve input controls on excavator?! #4  
Hmm, do you mind explaining this a bit more?

Is the issue the 'valve bank' or is it the control (valves). I have valves in the controls (as far as I can tell; see photo of the underside of the control stick). Not sure, if these operate the (real) valves or not. Or are the joystick valves it?

It’s most likely the actual valves. Good ones can operate smoothly and cheaper ones tend open all or nothing.
 
   / Improve input controls on excavator?!
  • Thread Starter
#5  
It’s most likely the actual valves. Good ones can operate smoothly and cheaper ones tend open all or nothing.
Thanks for getting back to me.

However, it is still not clear to me if there are two sets of valves; e.g. the valves under the stick, and the actual actuator valves for the cylinders? (Or the stick valves control the cylinders?)

---

OK, I am starting to watch Youtubes on hydraulics. They talk about pilot valves and the valve block. Meaning there are two valves (of sort) for moving cylinders.
I assume, the stick has the pilot valves and the valve contains the spool for the cylinder movement.

Coming back to my original question: where is the jerkiness originating from? The pilot valve or the actuator valve in the valve block?

I do not have a pressure gauge (yet), but I can regulate the hydraulic pump speed. I understand the pressure is pretty constant across the speed range, but the flow changes as speed changes (increased speed, increases the flow).

I haven't done much work on the new digger; in fact, I worked it for ten minutes so far... my neighbour has a 3t Sany, which has excellent stick/boom control. I could immediately run the bucket run parallel to the ground.
What I will do is more experimenting with different pump speeds and how this affect the stick/boom movements.

I then learn more about these hydraulics to figure out what can be done to improve the or rather get rid of the jerkiness.
 
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   / Improve input controls on excavator?! #6  
How do your present joysticks connect to the main valves that operate the cylinders? Are there small hydraulic (pilot) lines connecting joystick to main valves or mechanical linkage? From your description suspect hydraulic pilot lines.

If hydraulic pilot I would start by installing gauges in those lines to see if joy sticks ramp pilot pressure up smoothly or does pilot pressure just jump up. Not sure what the pilot pressure will be but would suspect 500 PSI or less.
 
   / Improve input controls on excavator?!
  • Thread Starter
#7  
The digger came without any documentation! Not a single page.
I have no clue where the oil filter is, what type; fuses and sizes, etc.
A big learning curve (I am not afraid of), but hydraulics won't be learned in a day :)
I will eventually create a separate post with my experience about purchasing this digger.

I am going to operate the machine today and see what I can do from a human input perspective.
I have to figure out what pieces of metal to remove, to 'find' whatever valves there are and take some photos.
I will draw up electrical and hydraulic plans as I go... simply to be able to service the digger as needed.

You said "install gauges". Do you mean get a bunch and install them in the pilot lines, or get one and move it from one line to the next? I reckon the latter.
 
   / Improve input controls on excavator?! #8  
I would get one gauge to start with to monitor the pilot pressure. For main system pressure suspect you will need 3,000 PSI gauge so might want to get one of each if ordering parts. I also suspect machine will be metric or BSPP style threads so will probably also need some adapters of unknown size.
 
   / Improve input controls on excavator?! #9  
I would get one gauge to start with to monitor the pilot pressure. For main system pressure suspect you will need 3,000 PSI gauge so might want to get one of each if ordering parts. I also suspect machine will be metric or BSPP style threads so will probably also need some adapters of unknown size.
What pressure do you think it operates at? Without documentation its hard to know. I'd say go higher on the gauge. 5000 psi guages are standard.
 
   / Improve input controls on excavator?! #10  
What pressure do you think it operates at? Without documentation its hard to know. I'd say go higher on the gauge. 5000 psi guages are standard.
no clue but doubtful small Chinese unit would run high pressure pumps. My best guess would be similar to utility tractors in 2500 PSI range
can use 5,000 PSI if he wants just to be safe and not wrap a gauge
 
 
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