As shown in the assembly cross-section drawing, when the cam (420) is rotated clockwise,
the push rod (214) at the port 1 is pressed downward, which pushed the spool downward
with the help of the washer 1, the spring seat, the secondary-pressure-setting spring (324),
the washer 2 (217), and the washer 3 (313). As a result, the port P and the port 1 are joined
each other and the oil supplied from the pilot pump starts to flow into the port 1, generating
a flow pressure.
When the pressure at the port 1 increases to a pressure equivalent to the force of the
secondary-pressure-setting spring, having been set by the tilted operating section, the oil
pressure applied to the spool and the spring force are kept in balance, which keeps the port
1 outlet pressure constant.
Since the spool at the port 2 remains neutral, the return oil from the control valve flows out
through the tank port T.
Depending on the specifications, the push rod touches the top of the spool directly when the
operating section is tilted fully, which forcefully pushes down the spool, joining the port P
and the outlet port, resulting in an equal pressure at both ports.
2. Operation section damping mechanism
2.1 When the operating section is at the neutral position
As shown in the assemble cross-section drawing, the push rod is pushed upward by the
damping spring (336,337) through the piston (224).
2.2 When the operating section is tilted from the neutral position (Refer to the damping
operation explanation drawing (1))
As you see in the drawing, when the cam is rotated clockwise, the push rod at the port 1 is
pressed downward and the piston moves downward.
At this moment, the oil in the damping piston chamber passes out through the orifice in the
piston, producing a pressure used for damping.
On the other hand, the push rod at the port 2 is moved upward by the damping spring
through the piston.
At this moment, the oil in the tank room is absorbed into the damping piston chamber
through the 3 ball check valve portions (using the ball (225) and the bush(223)). The oil
outside the piston chamber flows through the path that joins with the port T at the top of the
casing.
2.3 When fully tilted operating section is tilted in reverse direction (Refer to the damping
operation explanation drawing (2))
In the operation explanation drawing, if the cam, having been fully tilted clockwise, is tilted
anticlockwise, the push rod at the port 2 is pushed downward and the piston moves
downward. At this moment, as in the case above, the oil inside the damping piston passes
out through the orifice in the piston, producing a pressure used for damping.
On the other hand, the push rod at the port 1 is moved upward by the return spring (335)
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