Aerostatic bearings design and analysis with the application to precision engineering: State-of-the-art and future perspectives

Effects of journal rotation and surface waviness on the dynamic performance of aerostatic journal bearings

Effects of manufacturing errors on the static characteristics of aerostatic journal bearings with porous restrictor

Effects of angular misalignment on the performance of rotor-bearing systems supported by externally pressurized air bearing

Numerical analysis and experimental investigation into the effects of manufacturing errors on the running accuracy of the aerostatic porous spindle

Effect of surface waviness on the static performance of aerostatic journal bearings

Hybrid air journal bearings are of great importance in the precision engineering. Despite much progress, the influence of the aerostatic effect and the aerodynamic effect on the bearings is still not clear. Numerical calculation is a useful technique to evaluate bearing performance. Many theoretical problems related to Reynolds equation have been figured out by numerical simulation. The present study analyzes the effects of rotational speed—that is, the bearing speed number—on the performance of hybrid bearings. The behaviors of the pure aerostatic bearing and the pure aerodynamic bearing are investigated for comparison. The second-order finite difference method (FDM) and an iterative procedure are proposed to solve the Reynolds equation and derive the air film pressure distribution. The bearing characteristics such as load capacity, stiffness, friction coefficient, attitude angle, and mass inflow rate are taken into consideration. The research reveals the very dependence of the hybrid bearing's p...

Numerical Calculation of Rotation Effects on Hybrid Air Journal Bearings

The invention provides a pitching adjusting mechanism. The pitching adjusting mechanism has the advantages that a trapezoidal lead screw with a self-locking function is shaken by a hand wheel of the pitching adjusting mechanism to drive a crank and slider mechanism to adjust an angle of the pitching adjusting mechanism; a machined part is supported by double arc guide rails and continuously adjustably rotate in the ranges from 0 degree to 60 degrees under the guidance effects of the double arc guide rails, and the amount of Z-direction movement of the machined part is lower than 20mm; support points of the arc guide rails and driving points of cranks and sliders are positioned at the upper end of the pitching adjusting mechanism, so that the rigidity of the upper end of the mechanism can be improved; the rotation angle can be read in a graduated scale and pointer indication mode; the machined part is clamped by a vacuum sucker; the pitching adjusting mechanism is a workpiece clamping device of a machine tool, the workpiece clamping device is applied to lateral edge machining, the amount of Z-direction movement of the machined part is low, and the integral pitching adjusting mechanism is high in integral rigidity, favorable for improving the surface figure accuracy and the surface quality of the machined part, simple in structure and convenient to disassemble.

Pitching adjusting mechanism

The utility model provides a shifting-fork precise flexibly-connected driving mechanism. Two-layer flexible connection of the shifting-fork precise flexibly-connected driving mechanism is realized via an elastic coupler and elastic flexible shifting pawls the elastic coupler can weaken influence on rotation precision of a spindle from a motor, and the elastic flexible shifting pawls can eliminate influence on the rotation precision of the spindle from a shifting fork disc. A pair of angular contact ball bearings is mounted between the motor and an air floatation spindle to bear bending moment caused to the motor from stress generated by different shafts of the motor and the air flotation spindle. The four flexible shifting pawls are divided into two groups, hollow nuts are utilized to adjust compression amount of springs so as to adjust the power of driving force of every two symmetrically arranged flexible shifting pawls, so that the flexible shifting pawls in each pair can drive at the same time. The shifting-fork precise flexibly-connected driving mechanism is arranged between the air flotation spindle and the motor, has low requirements on rotation precision of the motor, can greatly improve the rotation precision of the air floatation spindle after the driving of the motor, and is simple in structure and convenient to dismount and mount.

Zhang Lianxin

Papers

Effect of surface waviness on the static performance of aerostatic journal bearings

Effects of journal rotation and surface waviness on the dynamic performance of aerostatic journal bearings

Numerical Calculation of Rotation Effects on Hybrid Air Journal Bearings

Pitching adjusting mechanism

Shifting-fork precise flexibly-connected driving mechanism