The hydraulic motor is an actuator of the hydraulic sys […]
The hydraulic motor is an actuator of the hydraulic system that converts the liquid pressure energy provided by the hydraulic pump into the mechanical energy (torque and speed) of its output shaft. Liquid is the medium that transmits force and motion.
Hydraulic motors, also known as oil motors, are mainly used in injection molding machinery, ships, hoists, construction machinery, construction machinery, coal mining machinery, mining machinery, metallurgical machinery, marine machinery, petrochemical, port machinery, etc.
Hydraulic motors can also be classified into gear type, vane type, plunger type, cycloid type, etc. according to their structure types. Hydraulic motor manufacturers introduce the characteristics of five different types of hydraulic motors.
1.Gear hydraulic motor
In order to adapt to the requirements of forward and reverse rotation, the gear motor has the same inlet and outlet ports, has symmetry, and has a separate external oil drain port to lead the leakage oil of the bearing part out of the housing; in order to reduce the starting friction torque, a rolling bearing is adopted; The pulsating gear hydraulic motor has more teeth than the pump.
The gear motor has the advantages of small size, light weight, good self-priming performance and convenient maintenance. At the same time, the gear motor also has the disadvantages of large pressure and flow pulsation, low volumetric efficiency and input pressure, low output torque and high noise. Therefore, the gear hydraulic motor is only suitable for high speed and small torque. Generally used in agricultural machinery and other mechanical equipment that does not require high torque uniformity.
2. Blade motor
The vane motor is a hydraulic motor in which the vanes in the rotor slot are in contact with the casing (stator ring) to rotate the rotor under the action of the flowing liquid.
The blade motor has the advantages of small volume, uniform flow, stable operation, low noise, sensitive action, high input speed, etc.; however, the blade motor has large leakage, low speed stability, low input pressure, and cleanliness of oil pressure. The requirements are higher. Therefore, the blade type hydraulic motor is generally used in applications where the rotation speed is high, the torque is small, and the action requirements are sensitive.
3. Cycloidal motor
The cycloidal motor has a stator and a movable blade. The stator, the vane and the drive shaft divide the motor into two chambers. Each chamber has a port. When one port is oiled, the other oil is discharged. swing.
The cycloidal motor has the advantages of small size, light weight, good self-priming performance and convenient maintenance. However, at the same time, the cycloidal motor also has disadvantages such as large pressure and flow pulsation, low volumetric efficiency and input pressure, and small output torque. Therefore, the gear hydraulic motor is only suitable for medium and low speed and small torque.
4. Radial piston motor
(1) The single-acting link type radial piston motor is composed of a casing, a crankshaft, a distribution shaft, a connecting rod, a plunger, and an eccentric wheel.
Advantages: simple structure, reliable operation, large output torque and high pressure. Disadvantages: large volume, heavy weight, twisting and pulsating, low speed stability is poor.
(2) The multi-acting inner curve plunger motor increases the output torque and the torque ripple rate decreases under the same working pressure due to the increase in the number of equivalent plungers. Sometimes such a motor is made into a plurality of rows of plungers, the number of plungers is larger, the output torque is further increased, and the torque ripple rate is further reduced. Therefore, the motor can be made to have a large displacement and can be smoothly operated at a low rotational speed.
The radial piston motor is a low speed, high torque hydraulic motor. Low-speed hydraulic motors can be divided into single-acting and multi-acting modes according to their number of revolutions per revolution.
Advantages: small size, light weight, reliable operation, large output torque and high pressure. Disadvantages: complex structure, manufacturing difficulty and cost.
5. Axial piston motor
The working principle of the axial piston motor is that the oil distribution plate and the swash plate are fixed, and the motor shaft is rotated together with the cylinder body. When the pressure oil enters the plunger hole of the cylinder through the window of the oil distribution plate, the plunger protrudes under the action of the pressure oil, and the swash plate of the swash plate generates a normal reaction force to the plunger, and the force can be decomposed into the shaft. Dividing force and vertical force. The vertical component is balanced with the hydraulic pressure on the plunger, and the vertical component causes the plunger to generate a torque to the center of the cylinder, which drives the motor shaft to rotate counterclockwise. The instantaneous total torque produced by the axial piston motor is pulsating. If the motor pressure oil input direction is changed, the motor shaft output direction also changes. The change of the inclination angle a of the swash plate, that is, the change of the displacement, the larger the inclination angle of the swash plate, the larger the generated torque, and the lower the rotation speed.
Main features: high speed, small moment of inertia, easy to start and brake, high sensitivity of speed regulation and commutation, usually the output torque of high-speed hydraulic motor is not large.