RE 92202
/02.2015,
Bosch Rexroth AG
Axial piston variable pump |
A7VO Series 63
LA1 – Power controller with hydraulically proportional power override
13
LA1 – Power controller with hydraulically proportional power override
The power controller regulates the displacement of the
pump depending on the operating pressure so that a given
drive power is not exceeded at constant drive speed.
The hyperbolic power curve is approximated with two
measuring springs. The operating pressure acts on the mea-
surement area of a differential piston against the measuring
springs and an externally adjustable spring force which
determines the power setting.
If the sum of the hydraulic forces exceeds the forces of the
springs, the control oil is fed to the stroking piston, which
swivels the pump back to reduce the flow.
In a depressurized state, the pump is swiveled to its initial
position to
V
g max
by a return spring.
By connecting an external pilot pressure at port
X
3
, it is
possible to override the power control proportionally.
Increasing pilot pressure = reduced power.
▼ Characteristic curve LA1
Oper
ating pr
es
sur
e
p
A
[bar]
Se
tting r
ange
Beginning of contr
ol
400
350
300
250
200
150
100
50
0
0 0.2 0.4 0.6 0.8 1.0
V
g min
displacement
V
g max
The hydraulic output power (characteristic curve) is
affected by the efficiency.
When ordering, state in plain text:
▶ Drive power
P
[kW]
▶ Drive speed
n
[rpm]
▶ Maximum volume flow
q
V max
[l/min]
Please contact us if you need a power diagram.
LA1S – Power controller with load sensing
For description of load sensing, see page 12.
▼ Characteristic curve LA1S
350
200
min
max
V
g min
displacement
V
g max
Oper
ating pr
es
sur
e
p
B
[bar]
▼ Schematic LA1S
X
3
X
4
A
R
2
U
R
1
V
g min
V
g max
S