TM5-3805-263-14&P-3
HYDRAULIC SYSTEM
AND STEERING
Implement Valve in LOWER Position
IMPLEMENT VALVE FOR BLADE LIFT IN LOWER POSITION
1. Lever in LOWER position. 2. Valve spool in LOWER position. 3. Passage to tank. 4. Opening for head end of lift
cylinder. 5. Opening for rod end of lift cylinder. 6. Passage to tank. 7. Resolver valve. 8. Passage. 9. Valve for control
of oil flow. 10. Passage from pump. 11. Passage. 12. Check valve. 13. Passage for oil to shuttle valve in pump. 14.
Spring.
When the implement is in HOLD position, the
pressure of the pump oil to the implement valve is less
pressure of the oil in passage (10) is approximately 2150
than 1500 psi (103.5 kglcm2). When the blade gets to
psi (151.1 kg/cm2). Moving the control lever for the
the ground, more oil pressure is needed to move the
blade to LOWER position moves lever (1) which moves
blade down. When the increase in the pressure of the
valve spool (2) to the LOWER position. When valve
pump oil between the pump and the implement valve is
spool (2) moves to the LOWER position, the pressure of
more than 1500 psi (103.5 kg/cm2 ), there is not much
the oil from passage (11), through opening (4), through a
change in the output of the pump and the oil to the lift
line and a lock check valve, and in the head end of the
cylinder.
lift cylinder, is the same as the pressure of the oil from
the pump in passage (10). The pressure of the oil
When the pressure-of the oil from the implement
through resolver valve (7), through passage (8), and in
valve to the lift cylinder gets to approximately 1500 psi (
the chamber for spring (14), also has the same pressure
103 kg/cm2 ), the oil in the chamber for spring (14)
as the oil in passage (11) and in the chamber on the
opens check valve (12). The oil going through the check
other end of valve (9). Now, the force of spring (14) has
valve and passage (13), goes to the shuttle valve in the
the added force of the oil, which moves valve (9). As
pump and the shuttle valve moves. Now the pressure of
valve (9) moves it lets more pump oil go from passage
the pump oil to the head end of the lift cylinder can go as
(10), through passage (11), through outlet (4) and into
high as 3500 psi (246.1 kg/cm2 ). When a cylinder rod
the head end of the lift cylinder. The oil flow from the
goes to its extended position, the pump flow stops, but
pump to the head end of the lift cylinder is approximately
the pressure of the oil in the cylinder head goes to 3500
9 U.S. gym (34.1 litre/min). The
psi (246.1 kg/cm2 ). The implement valve spool in
flow is constant as the blade goes down and the
RAISE position (not shown) lets the pump oil in passage
(11) go
3-17
