What is a Hydraulic Pump?

What is a Hydraulic Pump?

The definition of hydraulic pump is a hydraulic system power element that is driven by an engine or an electric motor to convert mechanical energy into hydraulic energy.

Hydraulic pump is a power element of hydraulic system, which is driven by engine or electric motor, draws oil from hydraulic tank, forms pressure oil and discharges it to an executive element. Hydraulic pump is divided into gear pump, piston pump, vane pump and screw pump according to the structure.

Equipment Introduction

Hydraulic pump illustration symbol for hydraulic transmission to provide pressurized liquid, a hydraulic component, is a kind of pump. Its function is to convert the mechanical energy of the power machine (such as electric motors and internal combustion engines, etc.) into the pressure energy of the liquid. Many factors affect the service life of the hydraulic pump, in addition to the pump's own design, manufacturing factors and some of the components related to the use of the pump (such as couplings, oil filters, etc.) the choice, the operation of the commissioning process, etc. also have a relationship.

Hydraulic pump works on the principle of movement to bring about changes in the volume of the pump cavity, thereby compressing the fluid so that the fluid has pressure energy. Must have the condition that the pump cavity has a sealed volume change.

Commonly used categories

1. According to whether the flow can be adjusted can be divided into: variable pump and quantitative pump. The output flow rate can be adjusted according to the need is called variable pump, the flow rate can not be adjusted is called quantitative pump.
2. According to the pump structure commonly used in the hydraulic system is divided into: gear pump, vane pump and piston pump 3 kinds.

Gear pump, smaller volume, simpler structure, less stringent requirements for oil cleanliness, cheaper; but the pump shaft is subject to unbalanced forces, serious wear, leakage is larger.

Vane pump: divided into double-acting vane pump and single-acting vane pump. This pump has uniform flow, smooth operation, low noise, higher pressure and volumetric efficiency than gear pumps, and more complicated structure than gear pumps.

Piston pump: high volumetric efficiency, small leakage, can work under high pressure, mostly used in high-power hydraulic system; but the structure is complex, high material and processing accuracy requirements, expensive, high requirements for oil cleanliness.

Generally in the gear pump and vane pump can not meet the requirements only when the piston pump. There are some other forms of hydraulic pumps, such as screw pumps, etc.

Technical Features

Made of aluminum alloy, high strength, corrosion resistance, light weight, and suitable for operation in various environments.

The double-speed feature reduces the number of times of pressurization, and the low-pressure chamber is quickly put in a state of load and use, and is immediately converted to high pressure, shortening the cycle of each operation. Equipped with pressure regulating valve, can adjust control and set working pressure.

Couplings

1. Selection of coupling

Hydraulic pump drive shaft can not bear radial force and axial force, so it is not allowed to directly install the pulley, gears, sprockets at the end of the shaft, usually with a coupling to connect the drive shaft and pump drive shaft. If for manufacturing reasons, the coaxiality of the pump and the coupling exceeds the standard, and there is a deviation in the assembly, then as the pump speed increases the centrifugal force increases the coupling deformation, deformation and increase the centrifugal force. Resulting in a vicious circle, the result produces vibration noise, thus affecting the service life of the pump. In addition, there are factors such as loose coupling pins are not tightened in time, rubber ring wear is not replaced in time.

2. Coupling assembly requirements

The coaxiality error of the two shafts of the rigid coupling is ≤0.05mm, the coaxiality error of the two shafts of the flexible coupling is ≤0.1mm, the angle error of the two shafts is <1°, and the distance between the drive shaft and the pump end should be maintained at 5~10mm.

Selection of oil filter

General particle size in 10μm below the pollutants on the pump is not too obvious, and more than 10μm, especially in the 40μm above the life of the pump has a significant impact. Hydraulic oil in the solid pollution particles are very easy to make the pump relative moving parts surface wear intensified, for this reason need to install the oil filter to reduce the degree of oil pollution. Filtration accuracy requirements: axial piston pump 10 ~ 15μm, vane pump for 25μm, gear pump for 40μm. pump pollution wear can be controlled within the allowable range. High-precision oil filter is increasingly widely used, which can greatly extend the service life of hydraulic pumps.