Gear pump (motor): simple structure, good workmanship, small size, light weight, convenient maintenance, long service life, but low working pressure, large flow pulsation and pressure pulsation, such as when end face compensation is not used under high pressure, its Volumetric efficiency will decrease significantly.
Compared with external gear pumps, internal gear pumps have the advantages of more compact structure, small size, good oil absorption performance and better flow uniformity, but the structure is more complex and the processability is poor.
Vane pump: compact structure, small size, stable movement, uniform flow, low noise, long life, but more sensitive to oil pollution and more complex structure than gear pump.
The single-acting vane pump has an oil discharge port and an oil suction port. The rotor rotates once, and the volume between each two pieces of oil is sucked and drained once. If the eccentric distance between the rotor and the stator is made variable in structure, it is Variable vane pump. Single-acting vane pump is suitable for low pressure and large flow. Double-acting vane pump reciprocates the groove twice in the groove for one revolution of the rotor to complete oil absorption and discharge twice. Because it has two oil suction areas and two oil discharge areas, which are symmetrically distributed with respect to the center of the rotor, the forces acting on the rotor are balanced with each other and the flow is relatively uniform.
Plunger pump: High precision, good sealing performance and high working pressure, so it is widely used. But it has a complicated structure, high manufacturing accuracy, expensive price, and sensitive to oil pollution. Axial plunger pump is a plunger parallel to the axis of the cylinder and moves in the axial direction; the plunger of the radial plunger pump is perpendicular to the oil distribution shaft and moves in the radial direction. Both types of pumps can be used as hydraulic motors.
Screw pump: Screw pump is essentially a gear pump, which is characterized by simple structure and light weight; small pulsations of flow and pressure, uniform transportation, no turbulence, no agitation, and rarely air bubbles; reliable work, low noise, Smoother operation than gear pumps and vane pumps, high volumetric efficiency and high suction lift. But processing is difficult and the flow cannot be changed. Suitable for hydraulic transmission systems of machine tools or precision machinery. Generally, two-screw or three-screw pumps are used. There are two types of installation: vertical and horizontal. Generally used for vertical installation of marine screw pumps.
Gear motor: Simple structure and easy manufacture, but the output torque and speed pulsation are large, but when the speed is higher than 1000r / min, its torque pulsation is suppressed. Therefore, the gear motor is suitable for high speed and low torque. under.
Blade motor: compact structure, small size, smooth movement, low noise, and small load torque.
Axial plunger motor: compact structure, small radial size, small moment of inertia, high speed, easy to change, can automatically adjust the flow in a variety of ways, and has a wide range of applications.
Ball plug motor: large load torque, large radial size, suitable for medium speed conditions.
Internal curve motor: large load torque, low speed, good stability.