Abstract
This paper deals with displacement control of water hydrostatic bearing using a water proportional valve. Generally, the hydrostatic bearing supports the loads by varying the recess pressure according to the displacement of the supported object. The recess pressure varies with pressure drop through the bearing restrictor that has particular pressure-flow characteristics. Therefore, when the load acts on the hydrostatic bearing, eccentricity or displacement occurs, then the accuracy of positioning becomes worse. To solve this problem, displacement control of hydrostatic bearing with variable restrictor mechanism is required. The overlap of the spool valve of originally designed water proportional valve is used as the variable restrictor. The experiment results of the displacement control of water hydrostatic bearing are shown. Pressure difference between the top and bottom recesses increases by control of the displacement of the spool valve, consequently, the load capacity is increased. Maintaining the infinite stiffness with the experimental rig was achieved in the load range up to about 400 N.
