What is Hydraulic Motor

Figure 1: Hydraulic motors.

Hydraulic motor is an executive component of the hydraulic system, which converts the hydraulic pressure energy provided by the hydraulic pump into the mechanical energy (torque and speed) of its output shaft. Liquid is the medium of transmitting force and motion.

1. Function

Hydraulic motors, also known as oil motors, are mainly used in injection molding machinery, ships, hoists, engineering machinery, construction machinery, coal mining machinery, mining machinery, metallurgical machinery, marine machinery, petrochemical industry, port machinery, etc.

Figure 2: Hydraulic motors are widely used in industry

2. Characteristic

From the point of view of energy conversion, hydraulic pump and hydraulic motor are hydraulic components that work reversibly. Inputting working fluid to any kind of hydraulic pump can turn it into the working condition of hydraulic motor; On the contrary, when the main shaft of the hydraulic motor rotates driven by external torque, it can also change to the working condition of the hydraulic pump. Because they have the same basic structural elements -- closed and periodically variable volume and corresponding oil distribution mechanism.

Figure 3: Hydraulic components.

However, due to the different working conditions of hydraulic motors and pumps, their performance requirements are also different, so there are still many differences between the same type of hydraulic motors and pumps. First of all, the hydraulic motor should be able to forward and reverse, so its internal structure is required to be symmetrical; The speed range of hydraulic motor needs to be large enough, especially for its minimum stable speed. Therefore, it usually adopts rolling bearings or hydrostatic sliding bearings; Secondly, because the hydraulic motor works under the condition of input pressure oil, it does not need to have self-priming capacity, but it needs a certain initial sealing to provide the necessary starting torque. Due to these differences, the hydraulic motor and hydraulic pump are similar in structure, but they cannot work reversibly.

3. Use of Hydraulic Motor

Figure 4: Hydraulic motors of Okmarts.

Hydraulic pumps, motors, and cylinders can be combined into hydraulic drive systems. One or more hydraulic pumps, coupled to one or more hydraulic motors, constitute a hydraulic transmission.

Hydraulic motors are used for many applications now such as winches and crane drives, wheel motors for military vehicles, self-driven cranes, excavators, conveyor and feeder drives, cooling fan drives, mixer and agitator drives, roll mills, drum drives for digesters, trommels and kilns, shredders, drilling rigs, trench cutters, high-powered lawn trimmers, and plastic injection machines. Hydraulic motors are also used in heat transfer applications.

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