2-18
Power shift control
The set horsepower valve is shifted by
varying the command current level of
the proportional pressure reducing
valve attached to the pump.
Only one proportional pressure redu-
cing valve is provided.
However, the secondary pressure Pf
(power shift pressure) is admitted to the
horsepower control section of each
pump regulator through the pump's
internal path to shift it to the same set
horsepower level.
This function permits arbitrary setting of the pump output power, thereby providing the optimum
power level according to the operating condition.
The power shift pressure Pf controls the set horsepower of the pump to a desired level, as
shown in the figure.
As the power shift pressure Pf rises, the compensating rod (623) moves to the right via the pin
(898) and compensating piston (621).
This decreases the pump tilting angle and then the set horsepower in the same way as
explained in the overload preventive function of the horsepower control. On the contrary, the
set horsepower rises as the power shift pressure Pf falls.
(3)
Delivery pressure, (P
1
+P
2
)
Deliv
er
y flo
w
, Q
P
f
=MAX.
P
f
=MIN.
Servo piston
Small diameter
chamber
Large diameter
chamber
D
CL
P1
651
625
621 652
623 612 601
626
897
F
B(E)
875
611
P1
P2
140Z92RG05
Summary of Contents for HX130 LCR
Page 11: ...1 1 SECTION 1 GENERAL Group 1 Safety Hints 1 1 Group 2 Specifications 1 10 ...
Page 174: ...4 5 MEMORANDUM HYUNDAI HEAVY INDUSTRIES CO LTD CONSTRUCTION EQUIPMENT DIV ...
Page 536: ...8 108 125LCR8TM30 Turn casing 1 upside down and remove oil seal 3 using jig 29 ...
Page 566: ...8 138 Remove lock nut 22 and then boot 23 14 36078RL14 2507ARL10 ...