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4
A7VO Series 63 | Axial piston variable pump
Hydraulic fluids
Hydraulic fluids
The A7VO variable pump is designed for operation with HLP
mineral oil according to DIN 51524.
Application instructions and requirements for hydraulic
fluids should be taken from the following data sheets
before the start of project planning:
▶ 90220: Hydraulic fluids based on mineral oils and
related hydrocarbons
▶ 90221: Environmentally acceptable hydraulic fluids
▶ 90222: Fire-resistant, water-free hydraulic fluids
(HFDR/HFDU)
▶ 90223: Fire-resistant, water-containing hydraulic fluids
(HFC, HFB, HFAE, HFAS)
Viscosity and temperature of hydraulic fluids
Viscosity
Cold start
ν
≤ 1600 mm
max
Permissible temperature difference
Warm-up phase
ν < 1600 to 400 mm
Continuous operation ν = 400 to 10 mm
ν
= 36 to 16 mm
opt
Short-term operation
ν
≥ 7 mm
min
▼ Selection diagram
Maximum permissible viscosity for cold start
Range of optimum operating viscosity v
Optimum efficiency
Minimum permissible viscosity for short-term operation
Minimum permissible temperature for cold start
Bosch Rexroth AG, RE 92202/02.2015
Temperature
2
/s
θ
≥ -40 °C
St
ΔT ≤ 25 K
2
/s
θ = -40 °C to -25 °C
2
/s
θ = -25 °C to +103 °C
2
/s
2
/s
1600
1000
600
400
200
100
60
40
36
20
16
opt
10
7
-40
-25
Details regarding the selection of hydraulic fluid
The hydraulic fluid should be selected such that the
operating viscosity in the operating temperature range is
within the optimum range (ν
Note
At no point of the component may the temperature be
higher than 115 °C. The temperature difference specified in
the table is to be taken into account when determining the
viscosity in the bearing.
If it is not possible to maintain the conditions above due to
extreme operating parameters, we recommend flushing the
case at port U.
Comment
t ≤ 3 min, n ≤ 1000 rpm, without load p ≤ 50 bar
between axial piston unit and hydraulic fluid in the system
at p ≤ 0.7 × p
, n ≤ 0.5 × n
nom
This corresponds, for example on the VG 46, to a temperature
range of +5 °C to +85 °C (see selection diagram)
measured at port R
/R
1
2
Note the permissible temperature range of the shaft seal
(ΔT = approx. 12 K between the bearing/shaft seal and port R
Range of optimum operating viscosity and efficiency
t < 3 min, p < 0.3 × p
nom
Warm-up phase
-10
0
10
30
50
Temperature θ [°C]
, see selection diagram).
opt
and t ≤ 15 min
nom
70
90
115
/R
)
1
2
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