SANY LATIN AMERICA
4-32
SY195/205/215/225C9 Crawler Hydraulic Excavator
Structure and Function
Shop Manual - June 2013
Operation of pump
●
Cylinder block (7) rotates together with
shaft (1), and slipper (5) slides on
fl
at sur-
face (A).
●
When this happens, swash plate (4) moves
along cylindrical surface (B), so angle (a)
between central line (X) of swash plate (4)
and the axial direction of cylinder block (7)
changes.
●
(a) is named the swash plate angle.
●
With central line (X) of swash plate (4) at
a swash plate angle (a) in relation to the
axial direction of cylinder block (7),
fl
at sur-
face (A) acts as a cam in relation to slipper
(5).
●
In this way, plunger (6) slides on the in-
side of cylinder block (7), so a difference
between volumes (E) and (F) is created
inside cylinder block (7).
●
A single plunger sucks and discharges the
oil by the amount (F) – (E).
●
As cylinder block (7) rotates and the vol-
ume of chamber (E) becomes smaller, the
pressurized oil is discharged.
●
On the other hand, the volume of chamber
(F) grows larger and, in this process, the
oil is sucked.
●
As central line (X) of swash plate (4) over-
laps the axial direction of cylinder block (7)
(swash plate angle (a) = 0), the difference
between volumes (E) and (F) inside cylin-
der block (7)becomes 0.
●
Suction and discharging of pressurized
oil is not carried out in this state. Namely
pumping action is not performed. (In real-
ity, however, the swash plate angle is not
set to 0)
ZX215-1002021
1
4
5
7
B
X
a
A
ZX215-1002022
4
5
6
7
E
X
a
F
A
ZX215-1002023
7
4
E
F
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