Hitachi ZW180 Technical Manual page 191

Increase and Decrease Operations of Delivery
Flow
The displacement angle of swash plate (4) is
changed by the movement of servo piston 1 (3) and
servo piston 2 (6).
Movement of the servo piston is controlled by the
regulator. The feedback of the swash plate movement
is given to the regulator by feedback lever (7) and link
(8).
NOTE: Refer to the following pages as for
operation of the regulator.
•
Tilting Change Operation
Tilting center of the swash plate is located at A in the
drawings right.
Pilot pressure is always applied to servo piston 2 (6).
Therefore, when the circuit of servo piston 1 (3) is
connected to the hydraulic oil tank, swash plate (4)
tilts clockwise around A.
Conversely, as there are two servo pistons 1 (3),
when pilot pressure is applied to both of servo piston
1 (3) and servo piston 2 (6), swash plate (4) tilts
counterclockwise around A.
•
Feedback Operation
End of feedback lever (7) is inserted into the
projection on the side of swash plate (4). When
swash plate (4) tilts, the projection also moves, and
feedback lever (7) moves together.
For example, if swash plate (4) tilts to the maximum
displacement angle position from the minimum
displacement angle position, the center of feedback
lever (7) moves from B to C.
This movement of feedback lever (7) moves link (8),
and feedback is given to the regulator.
COMPONENT OPERATION / Pump Device
7
8
3
Minimum Displacement Angle:
3
Maximum Displacement Angle:
Projection
T3-1-3
A
Housing
A
7
8
Housing
C B
6
4
T4GB-03-01-022
6
4
T4GB-03-01-023
4
T4GB-03-01-024