Ren Fengzhang

Numerical simulation and experimental study of the air-cooled motorized spindle

In this study, numerical methods are used to investigate the flow and temperature fields of the air-cooled motorized spindle. The wind speed effects on the motorized spindle temperature and the relationships between the rotating speed, vibration and noise are studied experimentally. The purpose of this work is to provide the basis for optimization design of the air-cooled motorized spindle. First, the boundary conditions are defined and the wind speed in the heat sink groove, fluid field of the fan area and temperature distribution of the spindle in the thermal steady state are predicted by the finite element method. Second, the temperature, wind speed, vibration of the key points on the motorized spindle and the noise are measured experimentally. The results show that the wind speed of the fan area is high in the center and low near the wall. The spindle temperature is higher in the area of contact with the rotor and the front bearings, while changes in the heat sink section have little effect on the wind speed. It is found experimentally that the vibration, noise and temperature increase with rotating speed. The numerical and experimental results are consistent. It is suggested to improve the design of the motorized spindle through optimizing the blade structure to decrease the temperature, vibration and noise.

Numerical Simulation and Experimental Study of the Hydrostatic Spindle with Orifice Restrictors

Based on the theory of hydrostatic bearings, this paper presents a study of replacing the rolling bearings in a cold drawing spindle with the liquid hydrostatic bearings. An unloading mechanism is designed, containing two hydrostatic radial bearings and a thrust bearing, according to the mechanical characteristics of the spindle. In this study, a mathematical model of the hydrostatic bearing oil pad is developed. The effects of the rotating speed on pressure and flow fields of the oil pad are simulated using the finite element analysis and verified experimentally. The pressure in all recesses decreases with the rotation speed. Oil velocity of the radial hydrostatic bearing recess increases with the rotation speed, while the fluid flow velocity has almost no correlation with the rotation speed of the thrust bearing. The numerical and experimental results of the pressure in the recesses are consistent, confirming the validity and feasibility of this design.