Hyundai R 160 LC-3, Service Manual

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Main relief valve operation
High pressure setting pilot signal : OFF
This relief valve is built in between the pump port side(1) and low pressure passage.
Piston(E) is seated right end by spring(C).
Hydraulic oil from the pump port side enters chamber(3) via orifice(2) of main poppet(A).
Because d
2
<d
1
, main poppet(A) is securely seated.
When hydraulic oil reaches the pressure preset by spring(C), pilot poppet(D) opens; oil flows
around poppet(D) and into the low pressure passage via side hole(4) and passage(5).
(4)
ڸ
Low pressure Passage
Main poppet(A)
From pump
port side
Spring(B)
Spring(C)
Pilot poppet(D)
Piston(E)
5
4
Pilot poppet(D)
Spring(C)
A.
B.
1 2 3
(Pz)
d
2
d
1
5 4
Pilot
signal : OFF