2-17
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 propor tional pressure
reducing 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.
651
625
CL
P1
897
875
D
Servo piston
Large diameter
chamber
621
652
623
612
601
626
Small diameter
chamber
P1
P2
F
611
B(E)
898
14W92RG05
Summary of Contents for HX140L
Page 12: ...SECTION 1 GENERAL SECTION 1 GENERAL Group 1 Safety Hints 1 1 Group 2 Specifications 1 10...
Page 209: ...4 5 MEMORANDUM...
Page 694: ...8 68 125LCR8TM30 Turn casing 1 upside down and remove oil seal 3 using jig 29...
Page 734: ...8 108 Assemble plug 2 Plug NPT1 16 11 EA 17 21078TM68 21078TM69 21078TM70 21078TM71...
Page 756: ...8 130 Remove lock nut 22 and then boot 23 14 36078RL14 2507ARL10...