In order to obtain the optimal cooling water velocity, the relationship between motor spindle temperature and cooling water velocity was derived by using the heat transfer and fluid mechanics. When the cooling water velocity was relatively small, its change has significantly influence on cooling effect; But when the cooling water velocity was relative large, the difference in cooling effect was inappreciable. Motor spindles water cooling system based on the software of ANSYS CFX was established. The cooling water velocity and temperature distribution in circular channel was analyzed. Motor spindle temperature of theory and simulation was compared under different cooling water velocity; Experiments were conducted according to the results of the simulation, Experimental temperature is consistent with simulation results, which verify the validity of motorized spindle simulation analysis and theoretical derivation. The study in this paper provides a reference for the motorized spindle selecting the rational velocity of cooling water.

Different grinding parameters of silicon nitride ceramic are researched at the process of internal grinding. The influences on the roughness of surface by the linear speed of grinding wheel (vs), radial feeding speed (f) and axial vibration speed (fa) are studied in the uniformity testing. The experimental equation of silicon nitride ceramic internal grinding is optimized. The machined surface morphologies of the ceramic specimen are measured by roughness instrument of Taylor-Hobson Surtroni-25 and scanning electron microscope of S-4800. The results show that with the increasing of the linear speed of grinding wheel the roughness of surface get reduced, and with the increasing of radial feeding speed the roughness of surface get raised. It is also inversely proportional to the axial vibration speed. The linear speed of grinding wheel has the biggest impact on the roughness of surface of the silicon nitride ceramic internal grinding among the three grinding parameters. With the increasing of linear speed of grinding wheel, the value of roughness of surface declines from 0.4095μm to 0.1726μm. The influences on the roughness of surface of the silicon nitride ceramic internal grinding by different factors are found out in the research, and its removal mechanisms are cleared up under different linear speeds of grinding wheel.

Two-point method designed of the test system for application, the precision of the motorized spindle rotation was dynamic measurements. The system consists of standard bars, high-precision non-contact eddy current sensor. Analyzed by a mathematical model to establish error separation, measurement of two spindle rotation accuracy. The use of two isolated error method for processing the experimental data obtained spindle rotation accuracy at different speeds. Studies have shown that when the spindle speed of 10,000 rpm rotational error is small and tends to be more stable. Identify the factors that affect the accuracy of spindle rotation and summarized. Spindle rotation accuracy on-line monitoring and speed control provides an important theoretical, experimental basis.

Engineering ceramic is the ideal material for high-speed and high precision motorized spindle due to perfect characteristics of light weight, wear resistance, high temperature, high strength, and so on. The air-gap is changed due to the influence from various factors not only the tolerance of the manufacture and assembly of motorized spindle but also different working condition. The change of air-gap impacts on vibration performance of motorized spindle. The effects of rotating speed and air-gap between the rotator and stator on these characteristic parameters of the motorized spindle are analyzed. This paper analyses the effect change of air-gap on vibration performance of motorized spindle by the simulation analysis and experimental. The results show that vibration increase with the decrease of air-gap. Meanwhile, electromagnetic vibration increase with the increase of eccentricity of motorized spindle. These results are very helpful to the structure optimization and application of the ceramic motorized spindle.

The increase of loss causes the temperature rise in motor, reducing the using life of spindle, which can seriously affect the performance of motor. Thus, accurate calculating of loss is meaningful to optimal design of electric spindle. In this paper, the losses both with load and without load were analyzed by time-step finite element method. As the result of simulation analysis, the spindle losses with load are higher than those without load. Comparison analysis indicates that losses are various with different load. And the load impacts on core loss mostly in ceramic spindle. In addition, in asynchronous ceramic spindle with 4N•m rated load, the core loss, solid loss and stranded loss are least when the load change from 1.8 N•m to 3.8N•m. Accordingly, the best operation condition under the influence of load in electric spindle is gained.