Hydraulic oil
Before the project starts, please refer to the sample leaflets RC 90220 (矿物油)， RC 90221 (environmentally friendly hydraulic oil) and RC 90223 (HF flame-retardant hydraulic oil) of our company for the selection of hydraulic oil and its application conditions.
When using HFA， HFB and HFC hydraulic oils， variable pump A11VO is not applicable. When using HF or environmentally friendly hydraulic oil， the technical parameters must be considered. If necessary， please contact our technical department. The type of hydraulic oil should be indicated on the order.
Working viscosity range
To achieve the best efficiency and service life， we recommend selecting the working viscosity (at the working temperature) within the following range：
Vopt = Optimal working viscosity 16... 36 mm 2/s
Related to the fuel tank temperature (open loop)
Viscosity limit
The viscosity limit value is as follows:
Vmin= 5 mm2/s The short-term (t < 3 min)
maximum allowable temperature is t max = +115 °C.
Note that even in localized areas (for example, in the bearing area), the maximum temperature of the hydraulic oil must not exceed 115 °C.
Vmax= 1600 mm2/s
Short time (t < 3 min)
Cold start (p ≤ 30 bar, n ≤ 1000 min1.tmin = -40°C).
Only for no-load startup. Within approximately 15 minutes, the optimal working viscosity must be achieved.
At temperatures ranging from -25°C to -40°C, special measures should be taken. Please contact our company. For detailed information on low-temperature operation, please refer to RC90300-03-B.
Filtering
The cleaner the hydraulic oil is filtered, the higher the cleanliness grade of the oil will be, and the longer the lifespan of the axial piston elements will be.
To ensure the functionality of the axial piston elements, the cleanliness level should be at least:
According to ISO 4406, 20/18/15 grade
When the hydraulic oil is at high temperatures (90°C to a maximum of 115°C), the lowest cleanliness grade is
According to ISO 4406, 19/17/114 grade.
If the above cleanliness grades cannot be achieved, please consult the supplier.
Shaft seal temperature range
The shell temperature range allowed for the fluorine rubber shaft sealing ring is from -25°C to +115°C.
Note:
When the temperature is lower than -25°C, a nitrile rubber shaft sealing ring (allowable temperature range: -40°C to +90°C) must be used.
Pump shell flushing
Variable pumps with control devices EP, HD, and DR or with stroke limiters (H., U.) that operate for a long time (t > 10 minutes) at zero position or with a working pressure < 15 bar, must have the shell flushed through the oil ports "T1", "T2", or "R".
Models with booster pumps (A11VLO) do not require shell flushing because some of the booster flow is directed to the shell. When the oil leakage from the shell exceeds the total loss of the rotating components and the controlled liquid flow, attention should be paid.
Booster pump (centrifugal pump)
The booster pump is a circulation pump. The A11VLO is supplied with oil through this booster pump, allowing it to operate at a higher speed. At the same time, this booster pump is also beneficial for cold starting in low-temperature and high-viscosity hydraulic oil conditions. Therefore, in most cases, it is not necessary to pressurize the oil tank. The maximum allowable oil tank pressure for the booster pump is 2 bar.
