Hydrostatic bearings with self-controlled restrictors using a diaphragm - Numerical analysis and experimental verification as a guideway

Hydrostatic bearing has advantages of high accuracy and high speed as a guideway of grinder for cam shaft and crank shaft. Reduction in number of bearing pockets is effective for manufacturing cost of the guide way. In our previous work, a numerical analysis based on Reynolds equation, which considers non-linearity of oil flow at restrictor, elastic deformation of plumbing and volumetric strain of air bubble in oil, is proposed for development of a hydrostatic bearing with self-controlled restrictor using a diaphragm. Important parameters for static stiffness of hydrostatic bearing are revealed by the simulation. The developed bearing has achieved three times higher stiffness in static response than that of the conventional bearing with orifice restrictor. In this research, a linear motion stage with less bearing pockets than those of conventional guideway is developed by employment of hydrostatic bearing with self-controlled restrictor. The developed guideway has achieved one-third of bearing area, compared with those of conventional guideway. Furthermore, flow rate of bearing oil has achieved one-third, compared with that of conventional one. According to the evaluation of static response, compliance and motion characteristics, the developed linear motion stage has demonstrated same performance as a guideway used hydrostatic bearing with orifice restrictor.