Piston pump basics
First, the working principle of the plunger pump
The plunger pump, as its name suggests, relies on a plunger as the main working component of the pump. The principle is no stranger to everyday life, such as syringes for doctors and hand-pressed water wells. The syringe used by doctors is the most vivid, consisting of a needle (cylinder), a piston (plunger), and a needle. The working principle is that the movement of the piston (plunger) in the needle tube (cylinder) changes the volume in the needle tube (cylinder) and pushes the medicine (hydraulic medium) out of the needle tip (pump port). The basic principle of the plunger pump is similar: by moving the plunger in the cylinder, changing the volume change in the cylinder, pushing the hydraulic medium out of the cylinder.
The plunger pump is added in principle to several parts:
First, automatic oil absorption and oil discharge parts (distribution part);
Second, in order to improve performance (increasing efficiency, reducing pulsation, reducing noise), the number of plungers is increased, and other structures are added and improved;
Third, in order to control the flow, various control methods have been added.
Second, the piston pump classification
In general, plunger pumps can be classified according to the following classification criteria.
The plunger pump can be divided into two types in the flow distribution mode: the valve type and the valve disc type valve type plunger pump (the above picture shows the three-cylinder plunger pump). According to the relationship between the plunger and the shaft, it is divided into: radial plunger Pumps and axial piston pumps (generally fitted with discs), axial piston pumps are divided into oblique and straight shafts. Radial Piston Pump Straight Shaft Axial Piston Pump Inclined Shaft Axial Piston Pump
According to the control method, it can be divided into: quantitative, variable (manual variable, pressure control, flow control, electro-hydraulic proportional control, etc.)
Third, the working principle of the direct axis piston pump
The focus here is on the straight-axis (swashplate axial piston pump).
Working principle of the direct-shaft piston pump: The plunger pump relies on the plunger to reciprocate in the cylinder body, so that the volume of the sealing oil chamber changes to achieve oil absorption and oil pressure. The plunger and the oil distribution plate form a plurality of sealed working oil chambers, and the swash plate inclination angle (the angle between the swash plate working surface and the direction perpendicular to the axis) is . There are several plunger holes in the cylinder, and the plunger slides in the plunger hole. When the drive shaft rotates with the cylinder and the plunger (counterclockwise), the plunger reciprocates in the cylinder. During the half cycle from bottom to top, the plunger gradually protrudes outward to make the cylinder The volume of the sealed oil chamber in the body increases, forming a partial vacuum, so that the oil enters the cylinder through the oil suction window a of the oil distribution plate. During the top half of the top-down period, the plunger is pushed back by the swash plate, and the volume of the seal oil chamber is reduced, and the liquid is discharged from the oil distribution window b. In this way, each time the cylinder rotates, the oil absorption and the primary pressure oil are completed.
Fourth, the advantages of axial piston pump
Compact structure, small unit power volume, high pressure, convenient variable mechanism arrangement and long service life
Five, conventional products
Domestic products: CY14 series Rexroth products: A4V, A7V, A8V, A10V, A11V, etc. Eaton, Danfoss, Atos, etc. have their products. This product is the localization of Rexroth A10VSO series products.
The main parameters are as follows:
Rated pressure Mpa 28 Displacement ml/R 18 28 45 71 100 140 Rated speed rpm 3300 3000 2600 2200 2000 1800 Rated flow L/min 59.4 84 117 156 200 252 Control mode direct drive, pressure control, remote pressure control, pressure / flow Control, pressure / flow / power control, flow electronic control, pressure / flow electronic control, electro-hydraulic pressure control, other combined string pump
Sixth, the main market of plunger pumps
Construction Machinery (Important Market), Plastic Machinery (Important Market), Agricultural Machinery, Metallurgical Mining Equipment, Machine Tools, Petrochemical Equipment