There are three types of hydraulic motors of the same base type, with rated pressures of 10, 16, and 20 MPa, and peak pressures of 16, 25, and 31.5 MPa. How to reasonably select a model that is more suitable for the operating conditions of the main engine? First of all, we should consider improving the transmission efficiency. For working conditions with low transmission efficiency, low speed and large torque, the main factor affecting the overall transmission efficiency is the volumetric efficiency. For hydraulic devices with the same transmission power, reducing the system working pressure can significantly improve the volumetric efficiency. Therefore, the model with rated pressure of 10MPa should be selected, and the actual working pressure should also be selected lower. When the transmission power is smaller, The lower the speed, the lower the working pressure is. Contrary to the working condition of high transmission power and high speed, the main factor affecting the overall transmission efficiency is mechanical efficiency, so the model with rated pressure of 16 or 20MPa should be selected. Secondly, for the working conditions with low speed stability requirements, the greater the displacement of the hydraulic motor, the better the low speed stability, which is also related to the working pressure, the lower the working pressure, the better the low speed stability.

How to select a reasonable model for several hydraulic motors of different base types with the same displacement? This is related to the operating conditions and service life requirements. For short-term intermittent operation, the machine with a short accumulated working time during the whole overhaul period can be selected with a smaller model number. For the machine with a long accumulated daily operating time and a longer service life, the machine with a larger model number should be selected as far as possible. If necessary, the machine with a high pressure should be selected, but it should be used under a lower pressure, At this time, the service life can be significantly increased, because the service life of the hydraulic motor is inversely proportional to the service pressure, that is, the service pressure is reduced by half, and the service life can be increased by 10 times.