Flushing And Boost Pressure Valve - Bosch Rexroth A6VM series 71 Manual

Flushing and boost pressure valve

The flushing and boost pressure valve is used to remove
heat from the hydraulic circuit.
In a closed circuit, it is used for flushing the case and safe-
guarding the minimum boost pressure.
Hydraulic fluid is directed from the respective low pressure
side into the motor housing. This is then fed into the reser-
voir, together with the leakage. The hydraulic fluid, removed
out of the closed circuit must be replaced by cooled
hydraulic fluid from the boost pump.
The valve is mounted onto the port plate or integrated
(depending on the control type and size).
Cracking pressure of pressure retaining valve
(observe when adjusting the primary valve)
▶ Sizes 60 to 215, fixed setting 230 psi (16 bar)
Switching pressure of flushing spool Δp
▶ Sizes 60 to 215 (small flushing valve) 115±15 psi (8±1 bar)
▶ Sizes 115 to 215 (medium and large flushing valve)
254±22.5 psi (17.5±1.5 bar)
Flushing flow q
v
Orifices can be used to adjust the flushing flows as
required. The following information is based on:
Δp = p – p = 365 psi (25 bar) and ν = 60 SUS (10 mm
ND ND G
(p = low pressure, p = case pressure)
ND G
Small flushing valve for sizes 60 to 115
Material number DIA [inch] (ø [mm]) q
of orifice
R909651766 0.047 (1.2)
R909419695 0.055 (1.4)
R909419696 0.071 (1.8)
R909419697 0.079 (2.0)
R909444361 0.094 (2.4)
Medium flushing valve for size 115
Material number DIA [inch] (ø [mm]) q
of orifice
R909449997 0.055 (1.4)
R909449998 0.071 (1.8)
R909431308 0.079 (2.0)
R909431309 0.10 (2.5)
R909431310 0.11 (2.8)
R902138235 0.12 (3.1)
R909435172 0.14 (3.5)
R909436622 0.16 (4.0)
2 /s)
Code
[gpm (l/min)]
v
0.9 (3.5) A
1.3 (5) B
2.1 (8) C
2.6 (10) D
3.7 (14) F
[gpm (l/min)] Code
v
1.3 (5) B
2.1 (8) C
2.6 (10) D
3.9 (15) G
4.8 (18) I
5.5 (21) J
7.1 (27) K
8.2 (31) L
Axial piston variable motor | A6VM series 71
Flushing and boost pressure valve
Large flushing valve for sizes 150 to 215
Material number DIA [inch] (ø [mm]) q
of orifice
R909449997 0.055 (1.4)
R909449998 0.071 (1.8)
R909431308 0.079 (2.0)
R909431309 0.10 (2.5)
R909431310 0.11 (2.8)
R902138235 0.12 (3.1)
R909435172 0.14 (3.5)
R909436622 0.16 (4.0)
R909449967 0.20 (5.0)
▼ Circuit diagram EP
G
U T
1
T
2
Flushing
spool
Flushing
orifice
Pressure retain-
ing valve
M
1
Information
▶ Port S only for sizes 150 to 215
a
▶ For a flushing flow greater than 9.2 gpm (35 l /min), it
is recommended that port S
prevent an increase in case pressure. An increased
case pressure reduces the flushing flow.
RE-A 91610/12.2015, Bosch Rexroth Corp.
[gpm (l/min)]
v
1.3 (5)
2.1 (8)
2.6 (10)
3.9 (15)
4.8 (18)
5.5 (21)
7.1 (27)
8.2 (31)
9.7 (37)
B
V
g min
V
g max
A
Sa
be connected in order to
a
63
Code
B
C
D
G
I
J
K
L
M