Bosch Rexroth AG
, RE 91001-01-X-B2/01.2016
4
A2FM for explosive areas
| Axial piston fixed motor
Hydraulic fluids
Viscosity and temperature of hydraulic fluids
Viscosity
Temperature
Comment
Cold start
ν
max
≤ 1600 mm
2
/s
θ
St
≥ −40 °C
t
≤ 3 min,
n
≤ 1000 rpm, without load
p
≤ 50 bar
Permissible temperature difference
ΔT
≤ 25 K
between axial piston unit and hydraulic fluid in the system
Warm‑up phase
ν
< 1600 to 400 mm
2
/s
θ
= −40 °C to −25 °C
at
p
≤ 0.7 ×
p
nom
,
n
≤ 0.5 ×
n
nom
and
t
≤ 15 min
Continuous operation
ν
= 400 to 10 mm
2
/s
this corresponds, for VG 46 for example, to a temperature
range of +5 °C to +85 °C (see selection diagram)
Temperature class T3
θ
= −25 °C to +90 °C
measured at port
T
observe permissible temperature range of the shaft seal
ring (
ΔT
= approx. 12 K between bearing/shaft seal and
port
T
)
Temperature class T4
θ
= −25 °C to +70 °C
ν
opt
= 36 to 16 mm
2
/s
Range of optimum operating viscosity and efficiency
Short‑term operation
ν
min
≥ 7 mm
2
/s
t
< 3 min,
p
< 0.3 ×
p
nom
▼ Selection diagram
-40
-25
-10
10
30
50
90
115
70
0
7
10
40
60
20
100
200
400
600
1000
1600
VG 22VG 32VG 46VG 68VG 100
16
36
Optimum operating viscosity range
v
opt
Optimum efficiency
Maximum permissible viscosity for cold start
Minimum permissible viscosity for short‑term operation
Temperature
θ
[°C]
Viscosity
ν
[mm
2
/s]
Continuous oper
ation
Warm‑up phase
Minimum permissible temperature for cold start
Filtration of the hydraulic fluid
Finer filtration improves the cleanliness level of the hydraulic
fluid, which increases the service life of the axial piston unit.
A cleanliness level of at least 19/17/14 is to be maintained
according to ISO 4406.
