Hyundai HX140L, Manual

Page: 61 / 819

2-13
Overload preventive function
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When the self pump delivery pressure P1 or the companion pump delivery pressure P2 rises, it
acts on the stepped part of the compensating piston (621). It presses the compensating rod
(623) to the right till the force of the outer spring (625) and inner spring (626) balances with the
hydraulic force. The movement of the compensating rod is transmitted to lever 1 (612) via pin
(875).
Lever 1 rotates around the pin (875) (E) fixed to the casing (601).
Since the large hole section (F) of lever 1 contains a protruding pin (897) fixed to the feedback
lever (611), the feedback lever rotates around the fulcrum of point D as lever 1 rotates, and then
the spool (652) is shifted to the right. As the spool moves, the delivery pressure P1 is admitted
to the large diameter section of the servo piston via port CL, causes the servo piston move to the
right, reduces the pump delivery, flow rate, and prevents the prime mover from being overloaded.
The movement of the servo piston is transmitted to the feedback lever via point D. Then the
feedback lever rotates around the fulcrum of point F and the spool is shifted to the left. The
spool moves till the opening between the spool (652) and sleeve (651) is closed.
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)
14W92RG03