-When the solenoid is switched 「OFF」:
The fluid in the PTO clutch is unloaded to the bank through port B.Consequently pressure P2
at passage(2) becomes zero,whereas the pressure at passage (1) is P1.Then the force imposed upon the
left side of spool (P1)overcomes the force imposed upon the right side
(P2+spring force),so that the spool is pushed rightwards to connect port P and part A. Therefore no
fluid from the pump is branched off to the PTO clutch; that is,all fluid flows to the control valve.
Fig. 9-39 PTO solenoid switch 「OFF」position
(1) Pressure-reducing valve.
This valve is composed of the spool,spring,and piston and bleeds off the surplus fluid from the pump
into the tank by actuating the spool when the fluid pressure exceeds the regulated pressure at port B
(2) Fixed orifice
This orifice controls the fluid flow at B in accordance with the pressure differential between the
secondary pressure of the pressure reducing valve and the PTO clutch actuating pressure.
(1)Passage (1)
(2)Passage (2)
(3)Pressure-reducing valve
(4)Changeover valve
(5)PTO clutch
(6)To control valve
9-20
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