Komatsu PC20R-8 Shop Manual page 47

2. Control of discharge amount
. As the swash plate angle
ference between the capacities E and F be-
comes larger, so the discharge amount Q in-
creases.
The swash plate angle
vo piston.
. The servo piston moves in a linear reciprocating
motion ( × ) under the signal pressure of TCC
and LS valve.
This linear motion is transmitted to the rocker
cam (4), which is supported by the cylindrical
surface of the case (3), and the rocker cam
slides in the semi-circular reciprocating direc-
tion ( ).
. The upper and lower pressure receiving area of
the servo piston are different from each other,
and to the pressure chamber of the smaller pis-
ton side (upper), discharge pressure (self pres-
sure) P of the main pump is always introduced.
P
To the pressure chamber of the larger piston
side (lower), output pressure P
is introduced.
Movement of the servo piston is controlled by
the relationship between pressures P
P and the proportion of the pressure receiving
EN
areas of the smaller and larger pistons.
PC20R-8 PC27R-8
a
becomes larger, dif-
a
is changed by the ser-
of the LS valve
EN
and
P
3 4
E
F
RKP01270
10-29