Komatsu ecot3 PC300LC-8 Shop Manual page 106

SEN01993-00
Operation of pump
q Cylinder block (7) rotates together with shaft
(1), and shoe (5) slides on flat surface (A).
q When this happens, rocker cam (4) moves
along cylindrical surface (B), so angle (a)
between center line (X) of rocker cam (4) and
the ax ial di rec tio n of cy li nder b loc k (7)
changes.
q (a) is named the swash plate angle.
q With center line (X) of rocker cam (4) at a
swash plate angle (a) in relation to the axial
direction of cylinder block (7), flat surface (A)
acts as a cam in relation to shoe (5).
q In this way, piston (6) slides on the inside of
cylinder block (7), so a difference between vol-
umes (E) and (F) is created inside cylinder
block (7).
q A single piston (6) sucks and discharges the oil
by the amount (F) – (E).
As cylinder block (7) rotates and the volume of
q
chamber (E) becomes smaller, the pressurized
oil is discharged.
q On the other hand, the volume of chamber (F)
grows larger and, in this process, the oil is suc-
tioned.
10
10 Structure, function and maintenance standard
q As center line (X) of rocker cam (4) matches
the axial direction of cylinder block (7) (swash
plate angle (a) = 0), the difference between
volumes (E) and (F) inside cylinder block (7)
becomes 0.
q Suction and discharge of pressurized oil is not
carried out in this state. Namely pumping
action is not performed. (Actually, however, the
swash plate angle is not set to 0)
PC300, 350-8