As the core power component of the hydraulic system, the hydraulic pump provides a certain pressure and flow for each hydraulic system. Therefore, selecting the appropriate hydraulic pump can reduce the energy consumption of the hydraulic system, improve the working efficiency of the hydraulic system, reduce the noise generated in the operation process, optimize the working performance and ensure the reliability of the hydraulic system.
The basic factors to be considered in the selection of hydraulic pump include:
(1) Adaptability of variable control.
(2) Characteristics of hydraulic pump calibration.
(3) The characteristics of oil and its relation to the wear speed of hydraulic pump.
(4) Pollution tolerance.
(6) Safety pressure and maximum working pressure of the system.
(7) Volume efficiency and total efficiency.
(8) Allowable speed of hydraulic pump.
(9) The flow rate required by the hydraulic system.
(10) The relationship among pressure, speed and flow.
(11) Resistance to pressure shock.
(12) Operational reliability and durability.
(13) Life expectancy at various loads and speeds.
(14) Oil absorption conditions.
(15) Leakage loss degree.
(16) Compatibility, cost and economic factors of the whole system.
The basic principle of hydraulic pump selection: according to the power of the main engine, working conditions and the requirements of the system for working performance, the first step is to determine the type of hydraulic pump, and then to select the flow and pressure value required by the system. When choosing the hydraulic pump, not only the flow, pressure, volume, and cost should be considered, but also many aspects need to be carefully selected. For example, in the hydraulic system, the compatibility of the hydraulic pump, as well as the reliability of the pump and the expected life of the pump, etc.
Compared with the use of medium high pressure or low pressure, only from the economic point of view, the external gear pump is cheaper than other pumps, but with the passage of time and the increase of pressure, its noise value will also increase significantly. For example, the pressure pulsation and noise of vane pump are smaller, so it is more suitable than external meshing gear pump under the condition of fixed medium pressure, but its total efficiency is lower than that of plunger pump.
Through a lot of experience, it can be concluded that the screw pump is more economical when the pressure value is 2 ~ 3 MPa. Such pump has no pulsation and is the quietest. When the oil immunity is in the appropriate value, it has a high reliability coefficient. The advantages of radial piston pump life is obvious, which is more suitable for high pressure occasions. When the working pressure of axial piston pump is 20 ~ 25 MPa, its life expectancy is about 40 000 h, but when the working pressure is 30 ~ 35 MPa, its life will be reduced to 15 000 H.
All aspects of the selected hydraulic pump adapt to the required hydraulic environment, so that the hydraulic pump can operate reliably in the hydraulic system.