Operation Section Damping Mechanism; Shuttle Valve Section - Kubota KX080-3 Workshop Manual

WSM KX080-3 Mechanism

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 down-
ward 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) and the damping
spring.
As in the case above, 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 to the tank port from the casing top.
In other words, the damping force is generated in both cases when the operating section is tilted from the
neutral position to the fully tilted position and from the fully tilted position to the neutral position.

3. Shuttle valve section

3.1 When the operating section is at the neutral position
The secondary pressure ports are both the same as the tank port T, so the shuttle
valve outlet port is also the same as the tank port T.
3.2 When the pilot valve operating section is tilted from the neutral position
When the one secondary pressure port generate the pressure, the ball(192) is pressed
to the other secondary pressure port and closed the port. The shuttle valve outlet
port pressure is the same as the one secondary pressure port. In other words, the
higher secondary pressure is selected and output from the shuttle valve outlet port.
IV-M-70
IV Hydraulic System