Festo 8065075 Brève Description page 44

Hydraulic power pack with load sensing variable displacement pump and constant displacement pump
Pump controller
The axial piston pump is equipped with a load-sensing pump controller. A load-sensing controller regulates
a pump according to the load pressure by adjusting the delivery rate.
• p
:
LS
At a complete standstill, the pump's swash plate is set to its maximum angle by the compression
spring (2). The drive shaft is set into rotary motion. The pump then delivers its maximum flow rate.
When the delivery rate exceeds actual consumption, pressure is built up at port P (p
counters the pressure from port LS (p
is greater than the spring force (9), the piston is pushed to the right against the spring. A connection to
the maximum pressure regulator is then opened. Pressure p
piston (6). As long as the maximum pressure has not been reached (p
upper controller and the adjustment piston (4) remains open. The adjustment piston is pushed to the
left against the spring by the inflowing hydraulic oil. The swash plate is swiveled back.
When p reaches a value of p
P
connection to the adjustment piston. The amount by which p
pre-stressing of the spring (9). This is adjusted with the screw (10).
If the pressure at p
adjustment piston, thus reducing the delivery rate.
If the pressure p
Hydraulic oil flows out of the adjustment piston's chamber into the unpressurized pump cavity. The
resetting force is applied by the spring (2).
• p
:
max
If p exceeds the value of p
P
the spring and hydraulic oil flows from P to the adjustment piston. The connection from the upper
controller is interrupted. The delivery rate is reduced.
44
) at the piston (7) in the pump controller. If differential pressure
LS
plus pre-stressing of the spring (9), the piston (7) blocks off the
LS
drops, the piston (7) moves to the right and hydraulic oil flows once again to the
LS
drops, for example due to increased consumption, the piston (7) is pushed to the left
P
which has been set with the screw (11), the piston (6) is pressed against
max
). This pressure
P
is applied to the spring (8) at the
P
), the connection between the
max
needs to be greater than p
P
© Festo Didactic 8068243
is dictated by
LS