HYDRAULIC PUMP MANIFOLD ISSUE TO UNDERSTAND 1

[BEMPE16524]

Hi Guys,

First of all i'm sorry i don't have complete information of this old system. Please see my attachment for overall hydraulic schematic (you can download the pdf too).

I have a problem to understand how the system function. I understand how the solenoid valve (SOV 7 and 8) operated but on the manifold, i cannot figure out how it is operated.
From my view, when the SOV is energized, it will direct the oil from P to A and straight to the manifold.

From here i'm not sure, does it operated the valve (34) thus turn on the pump? at the same time it go to pilot (43) and energize the internal valve?

What is valve 34? Is it just a connection to point 'x' in the hydraulic motor (pump) schematic as i found the model is Rextroth AA6VM55HD2/63W-VSD510A.

What is valve in red circle?

Can someone help me explain how these two banks work please.

R.Efendy

 

[HPost]

The valve (34) is the motor controller. The red circled valve is a pilot operated shut off valve that isolates the motor from the pump pressure.

The shut off valve is piloted open when the solenoid valve (directional control valve) is operated. At this point as pressure signal, regulated by a proportional pressure reducing valve in the manifold, is fed to the valve to open it to start the motor turning. The speed of the motor is controlled by the same pilot signal. This is fed to the motor 'X' port as you say. The proportional pressure reducer is used to vary the pressure and therefore change the displacement of the motor (speed).

 

[BEMPE16524]

So the valve in red circle is proportional pressure reducing valve?
That means only when the X port is open then only the flow will go through the valve in the manifold and turn the motor?
Is that correct?

R.Efendy

 

[HPost]

I have edited my post. I made an error. Sorry to confuse you.

The proportional pressure reducer cannot be seen on the images above. You need to open the PDF to see it.

It's in the main manifold, higher up in the drawing. It's under the directional control valve.

The pressure to the X port also goes to the shut off valve. The pressure opens the shut off valve and controls the motor speed. The motor will not turn unless there is pressure at the X port.

 

[BEMPE16524]

Now i wonder if these two valves (in red) are actually the same valves? What do you think?

R.Efendy

 

[HPost]

Yes, they are the same valve. Well almost...

The Bosch Rexroth is the fully detailed version.

I think that the person that drew the schematic on the PDF was short of room on the drawing sheet, so they drew a simplified version.

They are both displacement controllers for the motor, the end result is same.

Item 34 is the controller, the part that you have circled on the Rexroth version.

The part you have circled on your schematic is the control piston that moves the motor to control the displacement.

 

[BEMPE16524]

I think that's satisfied me now. Thanks HPost! Really appreciate your view.

R.Efendy