Overload Relief Valve - Doosan DX140R Shop Manual

Overload Relief Valve

Relief Valve Operation
1. This relief valve is inserted between the neutral path "HP"
and tank path "LP". Oil is filled in the inner space (G)
through the orifice of the piston (C).
The sleeve (K) and main poppet (D) are securely seated by
the areal difference between "A" and "B".
2. When the pressure in the cylinder port "HP" reaches the
preset spring force of the pilot poppet, the pilot poppet (E)
will be opened.
Oil flows around the poppet, through the drill hole (H), and
is guided to the low pressure path "LP".
3. The pilot poppet (E) opens to make the oil flow through the
orifice (1) of piston (C), differential pressure is generated
between path "HP" and the back side of the piston (C) to
move the piston (C) to seat the poppet (E).
Main Control Valve
Figure 29
Figure 30
Figure 31
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