types of hydraulic motors


There are many types of hydraulic motors, which can be roughly divided into the following six categories:


1. Vane type hydraulic motor

Due to the pressure oil, the unbalanced force causes the rotor to generate torque. The output torque of the vane hydraulic motor is related to the pressure difference between the displacement of the hydraulic motor and the oil inlet and outlet of the hydraulic motor, and its speed is determined by the flow rate of the input hydraulic motor. Since hydraulic motors generally require forward and reverse rotation, the blades of vane hydraulic motors should be placed radially. In order to make the blade root always pass the pressure oil, in the return, pressure oil cavity through the blade root should be set up check valve, in order to ensure that the vane hydraulic motor in the pressure oil after the normal start, must make the blade top and the stator inner surface close contact to ensure a good seal, so the blade root should be set preload spring. Vane hydraulic motor has small size, small moment of inertia, sensitive action, and can be applied to occasions with high commutation frequency: but the leakage is large and unstable at low speed. Therefore, vane hydraulic motors are generally used in occasions with high speed, small torque and sensitive action requirements.


2. Radial piston hydraulic motor

The working principle of the radial piston hydraulic motor, when the pressure oil enters the bottom of the plunger in the cylinder through the window of the fixed oil distribution shaft, the plunger extends outward and tightly presses against the inner wall of the stator, because there is an eccentric distance between the stator and the cylinder block. At the contact between the plunger and the stator, the reaction force of the stator on the plunger can be decomposed into two components. When the oil pressure acting on the bottom of the plunger is p, the plunger diameter is d, and the angle between the force and is X, the force generates a torque on the cylinder block and makes the cylinder rotate. The cylinder block then outputs torque and speed outward through the transmission shaft connected by the end face.


3. Axial piston motor

In addition to valve distribution, other forms of axial piston pumps can be used as hydraulic motors in principle, that is, axial piston pumps and axial piston motors are reversible. The working principle of the axial piston motor is that the oil distribution plate and the inclined boat are fixed, and the motor shaft is connected with the cylinder block and rotates together. When the pressure oil enters the plunger hole of the cylinder block through the window of the oil distribution plate, the plunger is in the pressure oil. The action is extended outward, and the swash plate is close to the swash plate to produce a directional reaction force p on the plunger, which can be broken down into axial and vertical components Q. Q balances with the hydraulic pressure on the plunger, while Q causes the plunger to generate a torque to the center of the cylinder block, driving the motor shaft to rotate counterclockwise. The instantaneous total torque generated by the axial piston motor is pulsating. If the motor pressure oil input direction is changed, the motor shaft rotates clockwise. The change of inclination of the swash plate, that is, the change in displacement, affects not only the torque of the motor, but also its speed and steering. The greater the inclination angle of the swash plate, the greater the torque generated and the lower the speed.


4. Gear hydraulic motor

Gear motor in the structure in order to adapt to the forward and reverse requirements, the oil inlet and outlet are equal, symmetrical, there is a separate oil leakage port to lead the leakage oil of the bearing part out of the shell, in order to reduce the starting friction torque, the use of rolling bearings, in order to reduce the torque pulsation gear hydraulic motor The number of teeth is more than the number of teeth of the pump.

Due to poor sealing, low volumetric efficiency, the input oil pressure cannot be too high, and large torque cannot be generated. And the instantaneous speed and torque change with the position of the meshing point, so the gear hydraulic motor is only suitable for high-speed and small torque occasions. It is generally used in construction machinery, agricultural machinery and mechanical equipment with low requirements for torque uniformity.


5. High-speed hydraulic motor

Motors with rated speeds higher than 500r/min are high-speed motors. The basic forms of high-speed motors are gear type, vane type and axial plunger type. Their main features are high speed, small moment of inertia, easy starting, braking, speed regulation and commutation.


6. Low-speed hydraulic motor

Hydraulic motors with a speed of less than 500r/min are low-speed hydraulic motors. Its basic form is radial plunger type. The main characteristics of low-speed hydraulic motor are: large displacement, large volume, low speed, can be directly connected with the working mechanism, no need for deceleration device, so that the transmission mechanism is greatly simplified, the output torque of low-speed hydraulic motor is large, so it is also called low-speed high-torque hydraulic motor.


The above types of hydraulic motors can be manufactured in Hanjiu, Hanjiu is now the largest hydraulic products production company in northern China, has more than ten years of production experience, a wide range of products, common hydraulic equipment on the market can be produced, and after-sales service is perfect, all products have a one-year warranty, during this period of free technical support.


White hydraulic motor

Hydraulic pump motor


Read more!