How Hydraulic Pumps and Hydraulic Motors Are Different, Differentiated and Used

Both hydraulic pumps and hydraulic motors are energy conversion elements in hydraulic transmission systems. What exactly is the difference between the two? How to differentiate? Where are they applied? Elephant Fluid Power will give customers a clear explanation.

Similarities between hydraulic motors and hydraulic pumps

1. In principle, the hydraulic motor and hydraulic pump are reversible. If driven by a motor, the output is pressure energy (pressure and flow), which is the hydraulic pump ; if the pressure oil is input, the output is mechanical energy (torque and flow). speed), it becomes a hydraulic motor.

2. Structurally, the two are similar.

3. The hydraulic motor and the hydraulic pump have the same basic structural elements - a closed and cyclically variable volume and a corresponding oil distribution mechanism. The working principle of hydraulic motor and hydraulic pump is to use the change of sealing working volume to absorb and discharge oil.

For hydraulic pumps, oil is sucked when the working volume increases, and high-pressure oil is discharged when the working volume decreases. For hydraulic motors, high-pressure oil enters when the working volume increases, and low-pressure oil is discharged when the working volume decreases.

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Differences between hydraulic motors and hydraulic pumps

1. The hydraulic pump is a conversion device that converts the mechanical energy of the motor into hydraulic energy. It outputs flow and pressure, and it is hoped that the volumetric efficiency is high ; the hydraulic motor is a conversion device that converts the pressure energy of the liquid into mechanical energy, and outputs torque and speed. efficient. Therefore, the hydraulic pump is the energy device, and the hydraulic motor is the actuator.

2. The steering of the output shaft of the hydraulic motor must be able to rotate forward and reverse, so its structure is symmetrical; and some hydraulic pumps (such as gear pumps, vane pumps, etc.) have clear regulations on the steering, which can only be rotated in one direction, not at will Change the selection direction.

3. In addition to the oil inlet and outlet, the hydraulic motor has a separate oil leakage port; the hydraulic pump generally only has the oil inlet and outlet (except for the axial piston pump and piston pump spares), and the leakage oil in it is connected with the oil inlet.

4. The volumetric efficiency of hydraulic motors is lower than that of hydraulic pumps .

5. Usually the working speed of the hydraulic pump is relatively high, while the output speed of the hydraulic motor is low.

6. In addition, the oil suction port of the gear pump is large and the oil discharge port is small, while the suction port and the oil discharge port of the gear hydraulic motor are the same size.

7. The gear motor has more teeth than the gear pump.

8. The vane of the vane pump must be installed obliquely, while the vane of the vane motor is installed radially; the vane of the vane motor relies on the swallow-type spring at the root to be pressed against the surface of the stator, while the vane of the vane pump relies on the pressure of the root. Oil and centrifugal force act on the stator surface.

In terms of working principle, both hydraulic motors and hydraulic pumps work by changing the volume of the sealed working chamber. However, due to their different use purposes, there are many differences in structure, and generally they cannot be directly reversed.