Similarities：
1.In principle, hydraulic motors and pumps are reversible. If driven by an electric motor, the output is pressure energy (pressure and flow), which is the hydraulic pump; If the input pressure oil outputs mechanical energy (torque and speed), it becomes a hydraulic motor.
2.From a structural perspective, the two are similar.
3. Hydraulic motors and hydraulic pumps share the same basic structural elements - a sealed and periodically variable volume and corresponding oil distribution mechanism. The working principle of hydraulic motors and hydraulic pumps is to use changes in the sealing working volume for oil suction and discharge.
For hydraulic pumps, when the working volume increases, they absorb oil, and when the working volume decreases, they discharge high-pressure oil. For hydraulic motors, high-pressure oil enters when the working volume increases, and low-pressure oil is discharged when the working volume decreases.
Differences：
1. A hydraulic pump is a conversion device that converts the mechanical energy of an electric motor into hydraulic energy, outputting flow rate and pressure with high volumetric efficiency; A hydraulic motor is a conversion device that converts the pressure energy of a liquid into mechanical energy, outputting torque and speed, with the aim of achieving high mechanical efficiency. Therefore, hydraulic pumps are energy devices, while hydraulic motors are executive components.
2. The steering of the output shaft of the hydraulic motor must be able to rotate in both forward and reverse directions, therefore its structure is symmetrical; And some hydraulic pumps (such as gear pumps, vane pumps, etc.) have clear regulations on the direction of rotation, which can only rotate in one direction and cannot be changed arbitrarily.
3. In addition to the inlet and outlet ports, hydraulic motors also have separate leakage ports; Hydraulic pumps generally only have inlet and outlet ports (excluding axial piston pumps), and the leaked oil inside is connected to the inlet port.
4. The volumetric efficiency of hydraulic motors is lower than that of hydraulic pumps.
5. Usually, the working speed of hydraulic pumps is relatively high, while the output speed of hydraulic motors is low.
6. In addition, the oil suction port of the gear pump is large and the oil discharge port is small, while the oil suction and discharge ports of the gear hydraulic motor are the same size.
7. Gear motors have more teeth than gear pumps.
8. The blades of the vane pump must be installed diagonally, while the blades of the vane motor are installed radially; The blades of a blade motor are pressed against the stator surface by the swallow shaped spring at the root, while the blades of a blade pump are pressed against the stator surface by the pressure oil and centrifugal force at the root. In terms of working principle, both hydraulic motors and hydraulic pumps rely on changes in the sealed working chamber volume to operate. However, due to their different purposes of use and structural differences, they generally cannot be directly reversed and used interchangeably.
