Key points of vane pump
Key points of vane pump
(1) In application, vane pump, especially variable vane pump, is mostly used in fixed installation of industrial production equipment and ships. High pressure fixed vane pump can also be used in walking machinery.
As we all know, the hydraulic system of all kinds of metal cutting machine tools generally has low power (below 20kW), medium working pressure (commonly 7MPa), and requires the hydraulic pump to have stable output flow, low noise and long service life, which is in line with the characteristics of vane pump. Therefore, the hydraulic system of metal cutting machine tools is very suitable for vane pump as oil source.
The double vane pump is composed of low pressure large displacement pump and high pressure small displacement pump. Because three different flow rates can be obtained through superposition and switching, it is very suitable for those processing equipment with rapid advance and retreat and great difference in working feed speed. The typical application circuit of double vane pump is shown in Figure E. when the hydraulic actuator moves rapidly, the pressure oil output by low pressure large flow pump 1 flows into the system through one-way valve 4 and the pressure oil output by high pressure small flow pump Z. when the actuator moves slowly, the pressure of the system increases. When the pressure reaches the pressure regulating value of hydraulic control sequence valve 3, valve 3 opens to unload pump 1 and pump 2 flows to the system separately The system supplies oil. In order to ensure the reliable operation of the two pumps in the duplex pump in the above way, the set pressure of valve 3 should be 15% - 20% higher than the actual pressure required by the fast stroke, and the pressure regulating value of relief valve 5 should be at least 0.5MPa higher than that of valve 3. The advantage of this hydraulic circuit is its high efficiency.
For all kinds of small and medium-sized pressure processing, casting, rubber and plastic molding equipment with large load change in one operation cycle, because it is often necessary to "keep pressure" on the processing object or mold, the variable vane pump with pressure compensation function can meet these requirements with energy-saving operation mode, and the cost is low. However, due to the improvement of the working pressure of the hydraulic system in the new generation of mechanical equipment, as well as the great progress of other components, especially the modern variable displacement piston pump, in reducing noise and manufacturing cost, as well as pressure, speed, power, efficiency and alternative variable mode, the variable displacement vane pump shows a significant gap, with almost no other advantages except the lower price and better self-priming capacity There is a lot of potential. Therefore, a considerable part of the variable vane pump is inevitably replaced by the variable plunger pump with better comprehensive performance and more regulation methods, or the constant vane pump and internal gear pump driven by variable speed motor which are developing rapidly.
The new type of high performance vane pump can not only be used in the field of industrial hydraulic, but also replace the external gear pump for the hydraulic system of walking machinery. Especially in the field of car hydraulic and truck steering 1J force system has great advantages. In addition, it is widely used in construction machinery, heavy vehicles, marine deck machinery and aerospace equipment. Together with internal gear pump, they will become the mainstream products of high performance quantitative hydraulic pump in the future.
(2) Parameter selection and type selection
① Selection of rated pressure. The rated pressure of vane pump products are 7MPa, 1ompa, 16MPa, 2lmpa, 25MPa, 28Mpa and 30MPa. The rated pressure of the same vane pump product is different with different working medium and different rotating speed. The appropriate vane pump should be selected according to the working medium, rotating speed and working pressure of the system.
② The selection principle of nominal displacement, speed, driving power and multi pump parameters is the same as that of gear pump.
③ Precautions for model selection. Low noise vane pump products, such as vane pump, pin vane pump and so on, should be selected for indoor and environmental noise requirements. In general, the noise of double acting vane pump is lower than that of single acting vane pump, but the noise of some single acting vane pumps with some technical measures is not big. The service life and price of vane pump should be considered comprehensively, especially in the selection of variable vane pump or double acting vane pump, the energy saving effect and cost should be compared at the same time.