Over-Pressure In The Cylinder (Relief Valve Activated) - Kubota KX080-3 Workshop Manual

WSM KX080-3 Mechanism

4. Over-pressure in the cylinder (relief valve activated)

(1) If the cylinder pressure rises above the relief valve s pressure setting, the relief valve opens itself to gen-
erate a pressure in the chamber (k).
(2) The pressure in the chamber (k) moves the piston (1) toward the plug and the piston (2) toward the
spool. The piston (2) then pushes the spool against the spool s return spring force. Now the spool goes
over the stroke to open the passage from B-port to A-port, which lets the oil flow from the cylinder to the
main relief valve.
Fig. 5
(1)
(2)
(3)
IV-M-119
IV Hydraulic System
B port
A port
(h) Control
(k) Pilot chamber
(1) Piston 1
(2) Piston 2
(3) Spool