2-22
BUCKET OPERATION
5)
Bucket in operation
T1
T2
P1
Boom
Boom lock
valve comp
P1
Dr1
To cylinder head side
via B10 port
To A10 port via
cylinder rod side
P1 side parallel passage
Spool changeover
direction
B10
To bridge passage
in bucket comp.
A10
Bucket
Pb10
R35Z72MCV17
Bucket in operation
When the bucket in operation is carried out, the secondary pressure from the remote control valve
flows into Pb10 port to change over the bucket spool.
Since the P1 side bypass passage is shut off at the bucket section after the bucket spool
changeover, the oil flowed from P1 port flows through the check valve provided above the bypass
passage in the travel section into the P1 side parallel passage.
Also, since a passage between B10 port and the bridge passage is opened after the spool
changeover, the oil flowed into the P1 side parallel passage flows through the load check valve in
the bucket section into B10 port via the bridge passage and then the head side of the bucket
cylinder.
On the other hand, the oil returned from the rod side of the bucket cylinder flows into A10 port to the
tank passage that has opened with the spool's notch after the spool changeover. Then, the bucket
cylinder extends to make the bucket in.
