2-10
Flow reducing function
刮
As the pilot pressure Pi rises, the pilot piston (643) moves to the right to a position where the
force of the pilot spring (646) balances with the hydraulic force.
The groove (A) in the pilot piston is fitted with the pin (875) that is fixed to lever 2 (613).
Therefore, when the pilot piston moves, lever 2 rotates around the fulcrum of point B [Fixed by
the fulcrum plug (614) and pin (875)]. Since the large hole section (C) of lever 2 contains a
protruding pin (897) fixed to the feedback lever (611), the pin (897) moves to the right as lever 2
rotates. Since the opposing-flat section (D) of the feedback lever is fitted with the pin (548) fixed
by the tilting pin (531) that swings the swash plate, the feedback lever rotates around the fulcrum
of point D, as the pin (897) moves.
Since the feedback lever is connected with the spool (652) via the pin (874), the spool moves to
the right.
The movement of the spool causes the delivery pressure P1 to connect to port CL through the
spool and to be admitted to the large diameter section of the servo piston. The delivery
pressure P1 that is constantly admitted to the small diameter section of the servo piston moves
the servo piston to the right due to the area difference, resulting in decrease of the tilting angle.
When the servo piston moves to the right, point D also moves to the right. The spool is fitted
with the return spring (654) and is tensioned to the left at all times, and so the pin (897) is
pressed against the large hole section (C) of lever 2.
Therefore, as point D moves, the feedback lever rotates around the fulcrum of point C, and the
spool is shifted to the left. This causes the opening between the sleeve (651) and spool (652) to
close slowly, and the servo piston comes to a complete stop when it closes completely.
C
L
P
1
643
654
651
652
613
646
B(E)
874
897
C
A
875
611
548
531
D
Large diameter
chamber
Servo piston
Small diameter
chamber
Pi(from MCV)
29092MP09A