The Difference Between Hydraulic Motor and Hydraulic Pump

The Same Points of the Hydraulic Motor and Hydraulic Pump

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

From a structural point of view, the two are similar.

Hydraulic motor and hydraulic pump have the same basic structural elements: closed and can periodically change the volume and the corresponding oil distribution mechanism. The hydraulic motor and hydraulic pump working principle is the use of sealed working volume changes in the suction and discharge of oil.

For the hydraulic pump, the working volume increases when the suction oil is, and the working volume decreases when the discharge of high-pressure oil is. For the hydraulic motor, when the working volume increases, the high-pressure oil enters, and when the working volume decreases, the low-pressure oil is discharged.

The Difference Between Hydraulic Motor and Hydraulic Pump

A hydraulic pump is the conversion device that converts the mechanical energy of a motor into hydraulic energy, outputting flow and pressure, hoping for high volumetric efficiency; a hydraulic motor is the conversion device that converts the pressure energy of liquid into mechanical energy, outputting torque and speed, hoping for high mechanical efficiency. Therefore, the hydraulic pump is an energy device, while the hydraulic motor is an executive component.

Hydraulic motor output shaft steering must be able to forward and reverse, so its structure is symmetrical; and some hydraulic pumps (such as gear pumps, vane pumps, etc.) steering has clear provisions, only one-way rotation, and can not change the direction of choice at will.

In the hydraulic motor in addition to the inlet and outlet, there is a separate leak oil port; the hydraulic pump generally only inlet and outlet (except the axial piston pump), the internal leakage of oil, and the inlet port.

Hydraulic motor volume efficiency than the hydraulic pump is low.

Usually, the hydraulic pump's working speed is relatively high, and the hydraulic motor output speed is low.

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

The number of teeth of the gear motor is more than the number of teeth of the gear pump.

The vane of the vane pump shall be installed obliquely, while the vane of the vane motor is installed radially; the vane of the vane motor is relying on the root of the swallow spring so that it is pressed on the surface of the stator, while the vane of the vane pump is relying on the root of the pressure oil and centrifugal force action pressed on the surface of the stator.

From the working principle, the hydraulic motor and the hydraulic pump are relying on the seal work chamber volume change and work, but because the two use purpose is different, there are many differences in structure, which generally can not be directly reversible common.

Hydraulic Motor Classification

According to the structure: gear type, vane type, and plunger type are several main forms.

According to the speed, torque range: high-speed motor and low-speed motor.

The gear-type hydraulic motor structure is simple, cheap, and commonly used in high speed, low torque, and smooth motion requirements are not high occasions. Such as drive grinder, fan, etc.

Vane-type hydraulic motor rotation inertia is small, sensitive action, low volumetric efficiency, mechanical characteristics of soft, suitable for medium speed or more, torque is not large, the requirements of the start, change direction frequently occasions.

Axial piston motors have high volumetric efficiency, large adjustment range, and low-speed stability, poor impact resistance, commonly used in high-pressure systems with high requirements. If you want to buy different types of hydraulic motors, please visit MyMRO's online store, we have a wide range of hydraulic motors for sale.

Hydraulic Pump Classification

According to the structure: the piston pump, gear pump, and vane pump are three categories.

According to whether the displacement is adjustable: quantitative pump, variable pump.

According to the direction of oil discharge: one-way pump, two-way pump.

According to the pressure level: low pressure, medium pressure, medium and high pressure, ultra-high pressure pump.

Gear pump: smaller size, simpler structure, less stringent requirements for oil cleanliness, cheaper; but the pump shaft is subject to unbalanced force, serious wear, and larger leakage.

Gear pumps are widely used in mining equipment, metallurgical equipment, construction machinery, engineering machinery, agricultural and forestry machinery, and other industries.

Vane pump: divided into double-acting vane pump and single-acting vane pump. This pump has uniform flow, smooth operation, low noise, higher pressure, and volumetric efficiency than gear pumps and a more complicated structure than gear pumps. Lifting and transportation vehicles, construction machinery, hydraulic system selected high-pressure vane pump.

Plunger pump: high volumetric efficiency, small leakage, can work under high pressure, mostly used in high-power hydraulic systems; but the structure is complex, high material and processing accuracy requirements, expensive, high requirements for oil cleanliness. Plunger pumps are commonly used in diesel engines to deliver high-pressure fuel.