Bosch Rexroth A7VO 63 Series - LR... - Power Controller with Stroke Limiter; LRH1 - Hydraulic Stroke Limiter (Negative Control); Characteristic Curve LRH1; Schematic LRH1

RE 92202/02.2015, Bosch Rexroth AG
Axial piston variable pump | A7VO Series 63
LR – Power controller without power override
11
LR… – Power controller with stroke limiter
Due to the hydraulic stroke limiter, it is possible to change
or limit the displacement of the pump continuously across
the entire control range. The displacement is set propor-
tionally using the pilot pressure p
St
applied to port X
1
(maximum of 40 bar).
The power control overrides the hydraulic stroke limiter, i.e.
below the power characteristic (hyperbolic characteristic),
the displacement is controlled in dependence on the pilot
pressure. If the set flow or operating pressure exceeds the
power control characteristic, the power control overrides
and reduces the displacement along the hyperbolic charac-
teristic.
A control pressure of 40bar is needed to swivel the pump
from its initial position V
gmax
to V
gmin
.
The necessary control power is taken from the operating
pressure or the external control pressure applied to port Y
3
.
To ensure that the stroke limiter functions at a low operat-
ing pressure of <40bar, port Y
3
must be supplied with an
external control pressure of about 40bar.
LRH1 – Hydraulic stroke limiter (negative control)
▶ Control from V
gmax
to V
gmin
As the pilot pressure increases, the pump swivels to a
smaller displacement.
▶ Start of control (at V
gmax
) can be set to 4to15bar
When ordering, state the start of control in plain text.
▶ Initial position without pilot signal (pilot pressure): V
gmax
▼ Characteristic curve LRH1
control pressure increase (V
gmax
–V
gmin
) Δp=25bar
40
35
30
25
20
15
10
5
4
0 0.6 0.8 1.00.40.2
Displacement V
g
/V
g max
Pilot pressure p
St
[bar]
▼ Schematic LRH1
T
1
X
3
X
1
Y
3
B(A)
A
1
M
1
R
2
U
R
1
V
g min
V
g max
S
▼ Schematic LRDH1
T
1
X
3
X
1
Y
3
B(A)
A
1
M
1
R
2
U
R
1
V
g min
V
g max
S