Hydraulic Fluids - Bosch Rexroth Hagglunds DUc MS2 Installation & Maintenance Manual

22/88 Hägglunds DUc Drive unit | Scope of delivery
Viscosity,
20000
10000
5000
3000
2000
1000
Fig. 8: Selection diagram for viscosity ranges with straight fluids, i.e. viscosity index 100
Bosch Rexroth AB, Version 06.2020, RE 15326-WA

5.4 Hydraulic fluids

The Hägglunds hydraulic system is primarily designed for operation with hydraulic
fluids according to ISO 11158 HM.
Fluids by the standards given in Table 4 are suggested. Before the start of project
planning, see data sheet
information on hydraulic fluids and specific additional demands
Table 4: Suggested fluid types
ISO 11158
Mineral oil based and
mineral oil related hydraulic
fluids
Details regarding the selection of hydraulic fluid
The hydraulic fluid should be selected such that the operating viscosity in the
temperature range, as measured in the motor housing, is within optimum operation
range, see Fig. 8. General recommendation is to have a system temperature of
50°C, see dotted line in Fig. 8. A VG 68 fluid will render just above 40 cSt at this
point.
• Optimum viscosity range is 40 to 150 cSt.
• Running above 150 cSt or below 40 cSt results in reduced efficiency.
• Running above 400 cSt results in substantial efficiency loss.
• For pumps, the maximum start-up viscosity is 2000 cSt.
• For motors, starting at above 10000 cSt imparts unnecessary strain on parts.
• Running below 30 cSt may impact the service life.
• Running below 20 cSt may render instant seizure.
[cSt]
ν
600
400
300
200
150
100
80
60
50
40
30
20
14
-40 -30 -20 -10
-40 -22 -4 14
RE 15414, Hydraulic fluid quick
ISO 15380
Environmentally acceptable
hydraulic fluids
0 0 10 20 30 40
32 32 50 68 86 104
reference, for detailed
ISO 12922
Fire resistant hydraulic fluids
50 60 70 80 90 100
122 140 158 176 194 212
t
Temperature, [°C/°
DD00069413
110
230
F]