1. Why is it not suitable for hydraulic motor and gearbox to be used together?

One of the characteristics of hydraulic transmission is that the ratio of power to weight is large, and in general, the hydraulic motor circuit itself can complete the usual speed regulation and variable speed function. Therefore, if the hydraulic motor is used with gear gearbox, it will lose the characteristics of hydraulic control, and at the same time, the volume and cost of the equipment will be significantly increased.

2. Why should the drain port of the hydraulic motor return to the fuel tank alone?

Although from the general concept all the return oil pressure is not high (close to the atmospheric pressure), many hydraulic systems still have a certain pressure, and the hydraulic motor oil release cavity is not allowed to have pressure (the inner part of the hydraulic motor drain is connected to the shell cavity, the shaft seal of the motor only acts as a seal and does not withstand pressure. If this port is connected with other return lines, it is easy to cause damage to the shaft seal of the motor and lead to oil leakage). Therefore, the drain port of the hydraulic motor is not allowed to be connected with other return lines.

3. Why not enter the air in the hydraulic motor?

In the initial operation, the hydraulic system will inevitably contain air in the piping of the system. An important part of the system debugging is to exhaust the air in the system. This is particularly important for hydraulic motors. The hydraulic medium has a process of suddenly changing from high pressure to low pressure in the motor, and the process frequency is high, averaging about 10 times per revolution. When the hydraulic oil entering the motor contains air, cavitation can be locally generated at the pressure abrupt change, so that the motor can be quickly damaged.