Float Position Of Pilot Valve With Truck Body On Frame - Komatsu 930E-2 Shop Manual

FLOAT POSITION OF PILOT VALVE WITH
TRUCK BODY ON FRAME
Figure 7-5 shows the position of the hoist pilot valve
when the truck body is resting on the frame. However,
the hoist valve internal valves and spools will be in the
position shown in Figure 7-7.
Oil from the hoist pump enters the inlet sections of the
hoist valve in port (11), passes through check
valve (18), and stops at the closed high pressure pas-
sage (19) at the two main spools (7 & 8) as shown in
Figure 7-4.
L7-6
Pressure builds to approximately 60 psi (414 kPa) on
the pilot of the flow control valve (2) causing the valve
to compress the spring and open, allowing the oil to
flow the through hoist valve port (23) to the service
brakes for brake disc cooling and eventually back to
the tank. Between the hoist valve port (23) and the
brakes or heat exchanger, the cooling supply tee's to
orificed regulator valves. If supply pressure attempts
to increase above 35 psi (240 kPa), the regulator valve
opens and dumps to tank.
Oil also flows out hoist valve port (12) to port (12) on
the pilot valve, through the hoist pilot valve spool, and
out pilot valve port (10) to the tank. This oil flow is
limited by orifices in the inlet sections of the hoist valve
and therefore has no pressure buildup.
Hoist Circuit L07023