Bai Qin

Influence Research of Recess Shape on Dynamic Effect of Hydrostatic Thrust Bearing

This work describes a simulation research concerning dynamic effect of multi-pad hydrostatic thrust bearing having rectangular recess, sector recess, ellipse recess and I-shaped recess in order to solve the loading capacity of the hydrostatic thrust bearing. Three-dimensional pressure field of gap fluid between the rotation worktable and the base has been computed by using the Finite Volume Method. This study theoretically analyzes the influence of recess shape on dynamic effect of the bearing according to computational fluid dynamics and lubricating theory, and the simulation results indicate that an improved characteristic will be affected by recess shape easily. Through this method, the safety of a multi-pad hydrostatic thrust bearing having different cavities can be forecasted, and the optimal loading capacity of such products can be achieved, so it can provide reasonable data for design, lubrication, experience and thermal deformation computation for hydrostatic thrust bearing.

Simulation on Supporting Characteristics of Heavy Hydrostatic Thrust Bearing

The pressure field of the clearance oil film of the hydrostatic bearing in varies velocities was simulated based on Finite Volume Method (FVM) by the software of Computational Fluid Dynamics. In this article, a conclusion could be drawn that the viscosity has great influences on the pressure in the heavy hydrostatic bearing and it cannot be neglected especially in high rotating speed. The results of numerical calculations provide internal flow status inside the bearing, which would help the design of the oil cavity structure of the bearing in engineering practice.

Numerical simulation on cavity type influence of multiple oil pad hydrostatic guide fluid state

Hydrostatic guide oil cavity of heavy CNC vertical lathe have many type, familiar oil cavity type have rectangle, sector, ellipse, I-shaped. Aim at research the influence of difference oil cavity type for hydrostatic guide fluid state, which established the 3-D entity model of rectangle and sector and ellipse and I-shaped hydrostatic guide interstitial fluid. The cavity type influence law of the guide fluid state is revealed via compute the four oil cavity type fluid state of hydrostatic guide based on numerical simulation. The result showed that the velocity of interstitial fluid gradually increase along the guide radial from inner to outer, and to reach the most in the outer edge. The result testified that the linear velocity of touch fluid for rotary wall surface directly proportional to guide radius. Based on an overall consideration of various factors, the interstitial fluid velocity field distribution of sector cavity hydrostatic guide is the most uniformity, next is ellipse, rectangle, and I-shaped, and the velocity vector graph of interstitial fluid testified that the oil cavity inner have reflux phenomena. The numerical result sincerity showed the interior fluid state of bearing. And the simulation result for project that oil cavity optimum structure design supplied theory proof.

Research on Simulation and Design of Dynamical Vibration Absorption Lathe Tool with Large Length to Diameter Ratio

The dynamic simulation analysis method is adopted to investigate the dynamic damping characteristics of lathe tool with large length to diameter (L/D) ratio. The multi flexible body dynamical simulation model of dynamical damping lathe tool with large length to diameter ratio is built up according to the actual experiment lathe by using the software ADAMS and ANSYS. Simulation analysis of the multi flexible body dynamical model which has been optimized shows that the system damping performance is improved greatly. On this basis the relationship of rubber bush, mass body and vibration absorption cavity is discussed. And the result of the discussion indicates that the shape of rubber bush should be confirmed by repeatedly simulating the model.

Stiffness Simulation Analysis of Rubber Bush Mountings Subjected to Tilting Deflection

The finite element model of rubber bush mountings is built up. And the value of the reduced tilting stiffness is obtained directly by solving the model. The simulation data and the experimental data can be seen to agree very closely. This fully proves the reliability of the simulation model. Based on this simulation model, which has been parameterized, the influence of the axial length and inner and outer radii on the reduced tilting stiffness of rubber bush is studied by using the co-simulation of MATLAB and ANSYS.

Stiffness simulation analysis of rubber bush mountings

The finite element model of rubber bush mountings based on ANSYS is built up. And the value of the reduced radial stiffness is obtained directly by solving the model. The analysis of the experimental data, the theoretical calculation data and the simulation data indicates that the simulation model of the rubber bush which has been established is correct. Based on the simulation model, which has been parameterized, the radial stiffness characteristics of rubber bush are studied by analyzing the influence of the axial length and the Poissons ratio on the reduced radial stiffness. It is shown that the influence of the axial length on the reduced radial stiffness of short rubber bush is great and the influence of the Poissons ratio on the reduced radial stiffness of long rubber bush is great.

Research on influence of oil cavity shapes on carrying capacity of heavy hydrostatic bearing

Carrying capacity of heavy hydrostatic bearing is one of important indicators reflecting its performance. Aiming at the problem of influence of oil cavity shapes on carrying capacity of heavy hydrostatic bearing, use finite volume method to simulate gap film pressure field of heavy hydrostatic bearing with rectangular-shaped, sector-shaped, oval-shaped, and I-shaped cavity and study pressure field distribution law of four cavity shapes on the conditions of the same rotating speed, cavity depth and oil cavity area, then optimize oil cavity structure. Results show that pressure field distribution law of four cavity shapes is basically identical, but four kinds of cavities possess different carrying capacity which is respectively arranged as oval-shaped, sector shaped rectangular-shaped, and I-shaped cavity according to size. Simulation results and theoretical analysis are proved to have consistency, which provide valuable theoretical basis for selecting cavity shapes for heavy hydrostatic bearing in practical productions.

Optimal Parameters Analysis of Dynamical Vibration Absorption Lathe Tool with Large Length to Diameter Ratio

The multi flexible body dynamical simulation model of dynamical vibration absorption lathe tool with large length to diameter ratio is built up according to the actual experiment lathe tool by using the software ADAMS and ANSYS. The experiment data which are consistent with the simulation result verify the correctness of the multi flexible body dynamical model. Aiming at reducing the peak value of system frequency response, the dynamical vibration absorption system is optimized. The optimized frequency curve shows that the system frequency response is improved obviously. On this basis the influence of the mass of heavy turning body on the vibration system is discussed. Also, the relationship of the mass of heavy turning body and the optimal system parameters including equivalent stiffness coefficient and equivalent viscous damping coefficient is studied. This offers the design considerations about the structure of the dynamical vibration absorption lathe tool with large length to diameter ratio.

Research on Flow Press Servo-Valve Controlling Electro-Hydraulic Force Control System and Nonlinear Performance Analysis

The configuration and the work principle of the flow press hydraulic servo-valve was introduced in this paper, based on this and electromagnetic basic theory, the mechanics analysis of every main parts of the flow press hydraulic servo-valve and the liquid basic theory especially the flow continuity equation, the mathematic model of the flow press sever-valve was built, during the process of building the model, the author took into account the load moment brought by the pair of spray nozzles flow force and the load moment brought by the force couples back pole and the fundamental equation of the force moment motor. On the other hand, the author analyzed the influence of the nonlinear factor to system performance, and the nonlinear factor was valve port overlap length disaccord caused by machining error. The mathematic model of the electro-hydraulic force control system controlled by the flow press servo-valve with valve port error was built. The results of simulation and experiment showed that valve port error badly influenced the system performance, and that valve port error was the main reason of the pressure higher than the supply pressure, which is one of the two cylinder cavities. The simulation curve and the experiment curve were accord compared by system simulation and experiment results, so we can know that the mathematic model of the flow press sever-valve and of the electro-hydraulic force control system controlled by the flow press servo-valve is correct.

Research on Simulation Optimization and Experiment of Dynamical Vibration Absorption Boring Bar with Damping

The build-in dynamical vibration absorption system with damping is applied to increase the dynamic stiffness of a boring bar. According to construction and vibration features, multi flexible body dynamical model of the vibration absorption system is built up by using the software of ADAMS and ANSYS. Also the vibration characteristic of an actual boring bar is analyzed by using SA-78 2ch FFT analyzer. Through the analysis of simulation results and experimental data the accuracy of the model is validated. On this basis the influence of the radial stiffness coefficient of rubber brushes, the damping coefficient of damping fluid and the mass of heavy turning body on the vibration system is discussed by using the vibration analyses module of ADAMS. The simulation results verify the feasibility of the initial structure design; establish the design key points in the actual design. The multi flexible body dynamical model of the vibration absorption system has been simulated, optimized and analyzed. And optimized parameters are obtained finally. With these optimized parameters, actual dynamical vibration absorption boring bar with damping can be designed, and the dynamic stability of the bar is enhanced thereby.