Papers by Author: Wan Li Xiong

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Authors: Wan Li Xiong, M.Z. Lu, Hsian Wei Huang, Hai Qing Mi, Yan Wu
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Authors: Xue Bing Yang, Wan Li Xiong, Zhi Quan Hou, Ju Long Yuan
Abstract: Water-lubricated hybrid journal bearings have been developed to support the ultra-precision machine tool spindles, due to the prominent properties of high load capacity and stiffness, high rotational accuracy, excellent thermal stability, low power consuming and environmental friendliness. Quasi-analytical procedures are deduced to present a relatively easy and rapid method for estimating of the parameters of the water-lubricated hybrid bearings without resorting to complex full numerical calculation. The procedures are based on the lumped resistance method, which have been extended to the situation dominated by the turbulence and inertia effects. The results show good agreement with the full numerical solution, especially when the bearing operating at moderate eccentricities. The procedures can be taken as a real time analytical tool for parametric study and preliminary engineering design of water-lubricated hybrid journal bearings.
270
Authors: Jin Jiang, Y.X. Dai, Y.B. Zhang, R. Tang, Wan Li Xiong
Abstract: Aimed at the problem of multi-motor synchronization in multi-wire saw, Strategy based on model-free adaptive control (MFAC), which has some characteristics such as without accurate system model, without system identification and without complicated manual tuning, is produced. MFAC is based directly on pseudo-partial-derivatives (PPD) derived on-line from the input and output data of the system using a novel parameter estimation algorithm. It is suitable for multi-wire saw in such a complex system which is nonlinearity, strong interference and strong coupling. Overall design of multi-wire saw is analyzed. Control structure of multi-motor is given. Motion model of multi-motor synchronization is established. To speed of main motor for reference, supply spool motor and collect spool motor, which have similar dynamic characteristics with main motor, are adjusted adaptively to follow operation of main motor, and synchronization motion is ensured. The prototype experiments show that the method used is right and feasible.
660
Authors: Lang Lv, Wan Li Xiong, Ju Long Yuan
Abstract: Electrical and magnetic characteristics of motorized spindles have a great effect on machining quality of ultra-precision machine tools. Bad characteristics will result in significant heat losses, low efficiency and large vibration. Study on optimizing electrical and magnetic characteristics of an inverter-fed induction motor is presented in this paper. A method of optimization design of an inverter-fed induction motor is given. The method is used to design a motor used for an ultra-precision machine tool motorized spindle. By comparing the optimal design with the traditional one, it shows that the total electrical and magnetic heat losses are obviously decreased and the efficiency can be improved.
258
Authors: Xue Bing Yang, Wan Li Xiong, Zhi Quan Hou, Ju Long Yuan
Abstract: Multi-array hole-entry hybrid journal bearings have been widely applied to support the high speed precision machine tool spindle with small diameter used in high efficient inner grinding, due to their prominent properties of high rotation accuracy, high dynamic stiffness, high vibration damping and long life. But the imperfection of the hybrid bearing is the significant temperature rising in the oil film on the condition of high speed operation, which brings about the sharp decreasing of load capacity and the larger thermal deformation of the bushing that cause the bearing failure immediately. In this paper, CFD analysis of the temperature fields of the multi-array hole-entry hybrid journal bearing with various bearing construction parameters and operation parameters are presented. According to the simulation results, the temperature rising in the oil film can be controlled efficiently by optimizing the matching of the bearing construction parameters and operation parameters and excellent characteristics of load capacity and static stiffness have been obtained simultaneously.
731
Authors: R. Tang, Y.X. Dai, Y.B. Zhang, Ju Long Yuan, Wan Li Xiong
Abstract: The deflection of cutting wire on multi-wire saw is determined by cutting wire tension, diameter ingot feed force and some other factors, and it affects the quality of silicon wafers greatly. In this paper, the initial stage of cutting process is analyzed and modeled with three ODEs. Then the numerical solutions are solved by finding out the BVPs of each ODE. The numerical solutions showed the relationship between the deflection and the cutting parameters such as cutting wire tension, diameter and ingot feed force. This method is helpful for the further research of modeling the entire cutting process.
343
Authors: Zhi Quan Hou, Wan Li Xiong, Xue Bing Yang, Ju Long Yuan
Abstract: The dynamic characteristics of a hydrostatic and hydrodynamic journal bearing with two arrays of eight holes have been investigated theoretically by the three-dimensional Computational Fluid Dynamics (CFD) models with respect to equilibrium position. The various dynamic coefficients for design parameters, such as orifice diameter, length to diameter ratio, eccentricity ratio, supply pressure, and rotational speed, are analyzed systematically under the action of displacement disturbance and velocity disturbance which are considered by the User Definition Function (UDF) programs. Results show that the dynamic coefficients greatly affected by design parameters. The cross stiffness coefficients increase rapidly more than direct stiffness with an increase of length to diameter ratio and rotational speed. Conversely, the direct stiffness coefficients are larger than cross stiffness with an increase of supply pressure and eccentricity ratio. It indicates that the journal bearing with two arrays of eight holes is suitable for their applications to small diameter grinding spindle by the means of optimizing the operating parameters and the structural parameters in order to obtain a better dynamic characteristic.
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