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Function of main relief valve
The main relief valve is fitted in the casing B and functions as follows :
(10)
The hydraulic oil is filled up in the inside space chamber (A) from the path (P) through a hole of
the body (101) and a restriction of the plunger (511), and seats the plunger (511) against body
(101) securely.
When the pressure in the path (P) becomes equal to the set load of the spring (512), the poppet
(401) opens to make the hydraulic oil flow through a hole of the seat (2) (641), around the
poppet (401) and into the low pressure path (R).
Opening of the poppet (401) causes the pressure in the chamber (A) to fall and the plunger
(511) to open. As the result the pressurized oil in the path (P) runs into the low pressure path (R)
directly.
When the pressurized oil higher than pressure 2.2 MPa enters through the port PL1, it pushes
the piston (302) to change the relief set pressure of the spring (512) to the high pressure.
刮
刯
到
刱
511
641
(A)
101
401
512
302
R
P
PL1
3607A2MC27
