SANY LATIN AMERICA
4-101
SY195/205/215/225C9 Crawler Hydraulic Excavator
Structure and Function
Shop Manual - June 2013
Operation of parking brake
1) When travel begins
●
As the travel lever is operated, pressurized
oil from the pump activates counterbalance
valve spool (10), opens the parking brake
circuit, and flows to chamber A of brake
piston (12). Pressurized oil overcomes the
force of spring (11) and pushes piston (12)
toward the left.
●
Since the pushing force to plate (13) and
disc (14) disappears, plate (13) is sepa-
rated from disc (14) and the brake is re-
leased.
2) When travel stops
●
As the travel lever is placed in neutral,
counterbalance valve spool (10) returns to
the neutral position and closes the park-
ing brake circuit. The pressurized oil in
chamber (A) of brake piston (12) passes
through the ori
fi
ce of the brake piston and
is drained to the motor case. Brake piston
(12) is pushed to the right by spring (12).
Plate (13) and disc (14) are pushed to-
gether, and the brake is applied. As brake
piston (12) returns,
fl
ow of pressurized oil
is reduced with slow return valve (22). The
time delay will be set to activate the brake
only after the machine has stopped.
ZX215-1002099
10
22
A
12
13
14
11
M
Travel control valve
ZX215-1002100
10
22
A
12
13
14
11
M
Travel control valve
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