Tips from Hydraulic Motor Manufacturers: Six Key Considerations When Using Hydraulic Motors

Hydraulic motors, also known as oil motors, are primarily used in injection molding machinery, ships, hoists, construction machinery, engineering vehicles, coal mining machinery, mining equipment, metallurgical equipment, marine accessories, petrochemical equipment, and port cranes, among others. They offer advantages such as small size, light weight, simple structure, good process performance, insensitivity to hydraulic oil contamination, impact resistance, and low inertia. So, how much do we know about them? Let's discuss some key considerations when using hydraulic motors.

The speed range of hydraulic motors must be sufficiently wide, especially with regard to their minimum stable speed. Therefore, they typically employ roller bearings or negative-pressure sliding bearings. Additionally, since hydraulic motors operate under conditions of input pressure oil, they do not require self-priming capability but must have initial sealing to provide the necessary starting torque. Due to these differences, although hydraulic motors and hydraulic pumps are similar in structure, they cannot operate reversibly.

1. When the driven component has a large inertia and requires rapid braking or reverse operation within a short period, a throttle valve or buffer should be installed in the return oil line to prevent significant hydraulic shock and potential damage.

2. When using a fixed-displacement motor, if stable starting and stopping are desired, necessary pressure control or flow monitoring measures should be implemented in the circuit design.

3. When a hydraulic motor serves as the power unit for lifting or traveling equipment, a speed-limiting valve should be installed to prevent rapid descent of heavy loads or overspeed during downhill travel of lifting mechanisms, thereby avoiding serious accidents.

4. Due to inherent leakage in hydraulic motors, closing the inlet and outlet ports for braking will still result in gradual movement. For long-term braking, a separate brake should be installed to prevent rotation.

5. When a mold hydraulic motor requires full-load starting, attention should be paid to the starting torque value of the hydraulic motor, as the starting torque is typically lower than the rated torque. Neglecting this aspect for large hydraulic motors may make it difficult for the driven unit to start.

6. Since the back pressure (outlet pressure) of a hydraulic motor's pump oil is generally higher than atmospheric pressure, the motor's leakage oil line must be directed back to the oil tank directly and should not be connected to the hydraulic motor's return oil line.