1. The gear pump
Gear pump is a kind of pump commonly used in hydraulic system, which is divided into external meshing pump and internal meshing pump.
(1) External gear pump is mainly composed of main and driven gears, drive shaft, pump body, side plate and sealing elements. Wherein, the gear in the pump body meshing with each other and the two end cover and pump body constitute the sealing working volume. The meshing line of the gear separates the left and right cavities to form suction and pressure oil cavities. When the gear rotates in the direction shown in the figure, the gear teeth in the oil suction cavity are constantly disengaged, so that the sealing volume of the oil suction side increases constantly, forming a vacuum, and sucking oil from the oil tank under the action of atmospheric pressure; When this part of the oil is rotated into the left pressure oil chamber, the teeth in the cavity continue to enter the meshing, the sealing volume of the oil pressure side continues to decrease, the oil pressure, and is constantly pressed out, into the system, so as to complete the oil absorption and oil pressure process of the gear pump.
(2) The internal gear pump is divided into involute gear and cycloid gear (rotor pump). The working principle of internal gear pump is basically the same as that of external gear pump, which depends on the change of volume to achieve oil absorption and oil pressure. But in order to ensure that suction, pressure oil mouth separated, involute gear pump in the middle to add a crescent partition, and cycloid gear pump because of two gears only a tooth difference, in meshing can always ensure that suction, pressure oil does not communicate, do not need a crescent partition.
2. The plunger pump
Plunger pump according to the plunger and drive shaft is vertical or parallel and divided into radial plunger pump and axial plunger pump, it is the use of the plunger in the plunger hole reciprocating movement to change the volume, to achieve oil absorption and oil pressure.
(1) Radial piston pump is composed of stator, rotor, shaft sleeve, oil distribution shaft and plunger and other components. There is an eccentricity e between the rotor and the center of the stator. The oil distribution shaft is fixed, and the oil distribution window is opened along the upper circumference. The upper half of the oil distribution window corresponds to the oil suction port, and the lower half corresponds to the oil pressure port. When the rotor rotates clockwise, due to e. In the upper half of the plunger in the action of centrifugal force along the plunger hole thrown out. The volume at the bottom of the plunger is increasing. A vacuum is formed, and the oil is sucked into the oil cavity through the oil suction port on the oil distribution shaft. When the plunger continues to rotate, to the second half of the circle. As the volume at the bottom of the plunger decreases, the oil is compressed and the pressure begins to rise. It is fed into the system through the oil pressure port. Each rotation of the rotor completes the process of oil absorption and oil pressure. The displacement or flow rate of the pump can be changed by adjusting the value of E, so it is also called variable pump.
(2) The characteristic of the axial piston pump is that the plunger hole is parallel to the axis. It is composed of swash plate, plunger, cylinder block, oil plate, drive shaft, return disc, return spring and other components. The axis of the swash plate and the drive shaft have an Angle, the plunger in the return plate, return spring and oil pressure under the action of close to the oil plate.
3. Vane pump
Vane pump according to each turn suction, pressure oil times and divided into single - acting vane pump and double - acting vane pump. Single acting vane pump, also known as variable vane pump or non-balance vane pump, pump shaft every rotation suction, pressure oil each time. Double vane pump known as the quantitative vane pump or balanced vane pump, pump shaft every one week suction, pressure oil twice.
(1) The single acting vane pump is composed of stator, rotor, blade and oil distribution plate and other components. The inner surface of the stator is cylindrical, and there is an eccentric between the rotor and the center of the stator. The blade slides freely in the rotor slot, and the root of the blade passes the pressure oil in the oil chamber where the blade is located. Because each sealing volume every revolution, suction, pressure oil each time, so called a single acting vane pump.
(2) Double-acting vane pump is also composed of stator, rotor, blade, oil distribution pan and some other accessories. The difference between it and the single acting vane pump is that the rotor and the stator are concentric; The inner surface of the stator is composed of two long arcs, two short arcs and four transition curves. The oil distribution window is arranged symmetrically in the center of rotation. It is because of this structure that the rotor rotates every week, sealing the working chamber will complete oil suction and oil pressure twice, so it is called double acting vane pump. Because the pump has two oil pressure area and two oil absorption area, so the hydraulic pressure is balanced, so this kind of pump is also called the balanced vane pump.
