To decrease the negative influence of the poor working environment on lubricating performance, a new hydrodynamic
bearing with magnetic fluid is developed, whose lubricating performance can be significantly
improved by external magnetic field. The mathematical model of magnetic intensity generating by a solenoid,
which is designed as external magnetic field, is deduced according to Biot-Savart Law and validated by measurement
experiment. The direct relationship of load-carrying capacity of bearing and magnetic intensity of
external magnetic field is built, through analyzing the effect of magnetic flux density on magnetic fluid viscosity.
The results showed that solenoid is reasonable to apply as external magnetic field, and its theory works.
Magnetic intensity of external magnetic field can enhance and monitor the bearing load-carrying capacity until
magnetic fluid reaches magnetic saturation.