SANY LATIN AMERICA
4-37
SY195/205/215/225C9 Crawler Hydraulic Excavator
Structure and Function
Shop Manual - June 2013
●
The regulator controls the pump discharge
amount according to the command signal
pressure, keeping the driving power of the
pump lower than the engine output.
●
Pumps 1 and 2 are both equipped with a
regulator. Key components of the regulator
include a solenoid proportional pressure
reducing valve (1), a positive
fl
ow regulator
(2), a servo reversing valve (3) and a servo
piston (4). The regulator opens and shuts
the oil circuit of the servo piston (3) and
changes the tilting angle of the hydraulic
tank according to various command signal
pressure so as to control the pump dis-
charge amount.
4.4.5.1 Control mechanism makeup
Current control
●
The inclination (output delivery amount)
of the pump can be controlled freely by
changing of the command current I flow-
ing into the solenoid proportional pressure
reducing valve. This regulator applies posi-
tive
fl
ow control (positive control), through
which output delivery amount Q changes
according to the increase of command cur-
rent. Necessary current for corresponding
operation can be input through this control
mechanism. The pump only delivers nec-
essary oil amount and wastes no useless
power.
P
SV
a
1
2
3
4
ZX225-1102003
Function
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