The gear type hydraulic motor is simply referred to as a gear motor and has a simple structure, small size, light weight, small inertia, impact resistance, easy maintenance, and low requirements for oil filtration accuracy. However, the pulsation is large, the volumetric efficiency is low, the torque is small, and the low-speed performance is not good.
Gear motors can be divided into two types: one is a gear pump-based gear motor; the other is a specially designed gear motor. The former is similar in structure to the gear pump, and the latter takes into account some special requirements of the motor: if the motor is often started with a load, the impact and vibration of the external load is severe, and it must be able to rotate in both positive and negative directions.
The gear motor and the gear pump basically have the same structure, but because the gear motor needs to be loaded and started, and it is required to be able to rotate in the forward and reverse directions, the gear motor still has a difference in the actual structure and the gear pump.
The gear motor has poor sealing performance and low volumetric efficiency, so the input oil pressure cannot be too high, the torque is generally not large, and its rotation speed and torque both pulsate with the meshing of the gears. Therefore, geared hydraulic motors are generally used in high-speed, low-torque situations.