Chinese name
Fluid pump
Foreign name
fluid pump
driver
Engine or motor
structure
Gear pump, piston pump, vane pump and screw pump.
nature
A kind of hydraulic component
quick
navigate by water/air
classify
trait
Working principle of hydraulic pump
performance parameter
Repair and maintenance
brief introduction
Graphical symbols for hydraulic pumps
The hydraulic component that provides pressurized liquid for hydraulic transmission is a kind of pump. Its function is to convert the mechanical energy of power machines (such as motors and internal combustion engines) into the pressure energy of liquids. There are many factors that affect the service life of hydraulic pump, besides the design and manufacture of the pump itself, the selection of some parts related to the use of the pump (such as coupling, oil filter, etc.). ) and the operation during the trial run.
The working principle of hydraulic pump is that movement brings about the change of pump cavity volume, thus compressing fluid to make it have pressure energy.
The necessary condition is that the sealed volume of the pump cavity changes.
classify
Types of common hydraulic pumps:
1, according to whether the flow rate can be adjusted, can be divided into variable pump and fixed pump. Variable pump with adjustable output flow and fixed pump with non-adjustable flow.
2. According to the pump structure commonly used in hydraulic system, it can be divided into gear pump, vane pump and plunger pump.
Gear pump: smaller in size, simpler in structure, less demanding on oil cleanliness and cheaper in price; However, the pump shaft is subjected to unbalanced force, which causes serious wear and leakage.
Vane pump: it is divided into double-acting vane pump and single-acting vane pump. This kind of pump has the advantages of uniform flow, stable operation, low noise, higher working pressure and volumetric efficiency than gear pump, and more complicated structure than gear pump.
Internal structure diagram of hydraulic pump
Piston pump: high volumetric efficiency, small leakage, working under high pressure, mostly used in high-power hydraulic systems; However, the structure is complex, the requirements for materials and processing accuracy are high, the price is expensive, and the cleanliness of oil is high.
Generally, piston pumps are only used when gear pumps and vane pumps cannot meet the requirements. There are other forms of hydraulic pumps, such as screw pumps, but their applications are not as common as the above three.
trait
Aluminum alloy manufacturing, high strength, corrosion resistance, light weight, suitable for all kinds of environments.
The two-speed characteristic reduces the number of pressing times, and it is in the working state of load quickly in the low-pressure cavity, and it is immediately converted into high pressure, which shortens each operation cycle.
Equipped with pressure regulating valve, it can adjust, control and set the working pressure. form
***2 sheets
Vane pump is often used in hydraulic machinery industry.
connect
1, selection of coupling
The transmission shaft of hydraulic pump can not bear radial force and axial force, so it is not allowed to install pulley, gear and sprocket directly at the shaft end. Usually, the drive shaft and the pump transmission shaft are connected by a coupling. If, due to manufacturing reasons, the coaxiality of the pump and the coupling exceeds the standard and the assembly is deviated, the centrifugal force will increase the deformation of the coupling with the increase of the pump speed, which will increase the centrifugal force. Causing a vicious circle, producing vibration and noise, thus affecting the service life of the pump. In addition, there are some influencing factors, such as loose coupling pin not fastened in time, rubber ring not replaced in time, etc.
2, coupling assembly requirements
The coaxiality error of two shafts of rigid coupling is ≤ 0.05mm..
The coaxiality error of two shafts of elastic coupling is ≤ 0.1mm.
Two-axis angle error
The distance between the transmission shaft and the pump end should be 5 ~10mm;
hydraulic oil tank
1, selection of hydraulic oil tank
The main function of hydraulic oil tank in hydraulic system is to store oil, dissipate heat, separate air contained in oil and eliminate foam. First of all, consider the capacity of the fuel tank. Generally, the maximum pump flow of mobile equipment is 2 ~ 3 times, and that of fixed equipment is 3 ~ 4 times. Secondly, consider the oil level of the fuel tank. When all hydraulic cylinders of the system are extended, the oil level of the oil tank shall not be lower than the minimum oil level, and when the hydraulic cylinders are retracted, the oil level shall not be higher than the maximum oil level. Finally, considering the structure of the oil tank, the partition in the traditional oil tank cannot precipitate dirt, so a vertical partition should be installed along the longitudinal axis of the oil tank. A space is left between one end of the baffle and the end plate of the oil tank, so that the two sides of the baffle are communicated; the oil inlet and the oil outlet of the hydraulic pump are arranged on both sides of the baffle at the unconnected end, so that the distance between the oil inlet and the oil return port is the farthest, and the hydraulic oil tank has more heat dissipation function.