31 - 18
Operation (cont’d)
Overload Relief Valve
Relief Valve Operation
1
The Overload relief valve is situated between the
cylinder port (HP) and low pressure passage (LP). The oil
flows through the piston hole (C) and fills the inner
space (G). The sleeve (K) and the main poppet (D) are
seated by the difference (A) (B).
2
When the cylinder port (HP) reaches the pilot poppet
spring force, the pilot poppet (E) opens. Oil flows around
the poppet and through the drill hole (H) to the low
pressure passage (LP).
3
When the poppet (E) opens, oil flowing through the
throttle (I) of the piston (C) produces a pressure
differential inside the passage (HP) and the piston (C).
Piston (C) moves and poppet (E) seats.
4
The oil flow from the passage (HP) to the inner part of
poppet (D), increases the pressure differential between
the poppet (D) and and the piston (C) and the throttle (F).
The poppet (D) opens and the oil flows to passage (LP).
Suction Operation
1
When the cavitation occurs on the cylinder port (HP), the
anti-void unit supplies oil. The sleeve (K) opens if the
pressure of the cylinder port (HP) is lower than the low
pressure side (LP). The oil flows into the cylinder port
(HP) from the low pressure side (LP) to avoid the
cavitation.
Section E
Hydraulics
9803/6020
Section E
31 - 18
Issue 1
Control Valve
289900
Summary of Contents for JS70
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