Abstract: A contactless guided positioning table has a table body and a movable mount having five-axis control magnetic bearings for supporting the table body movably in a horizontal direction. A contactless linear motor horizontally drives the table body. A vacuum container contains the movable mount movably in a direction vertical to the moving direction of the table body. A coupling member is disposed through a flexible hollow member to secure a vacuum state of the vacuum container and couples the movable mount to an external driver. A controller controls the electric current applied to the magnetic bearings. There is no mechanical contact, such as a sliding guide face and ball screw motor, used in the movement of the table body, thereby preventing dust from being generated by friction due to direct contact. Further, the table does not require lubricating oil which would disadvantageously affect normal operation in a vacuum and effectively avoids deposition and removal of solids.

Abstract: A grinding machine control apparatus comprises revolution speed changing means effective to selectively change a high speed in the grinding or a low speed in the dressing operations, a change signal generating means to generate a dressing initiation signal after the lapse of a predetermined time after a grinding wheel spindly driving motor is turned off, and control means to change said revolution speed changing means in response to a change signal from said change signal generating means and operative to drive a driving motor of a grinding wheel at a predetermined low speed of revolution. In a high-speed grinding machine, the speed of revolution of a grinding wheel spindle is automatically changed to reduce from a high revolution speed in the grinding operation to a low speed in the dressing operation without stopping a grinding wheel spindle so that a dressing operation can be carried out with good efficiency and a grinding wheel profile accuracy is substantially improved.

Abstract: A spindle device has pre-loaded anti-friction bearings which are so lubricated with oil jet accelerated through jet nozzles facing thereto that very high speed rotation with lower levelled vibration is permitted for the spindle.The spindle assembly has a rear bearing holder longitudinally slidable in the housing for pre-loading and cooling oil flows in the bearing holder. The spindle assembly further has a high frequency electric motor therein and is sealed up against dust penetration from outside.Air or oil vapor is prevented from staying in the sealed spindle assembly by a gas outlet which is provided in the assembly. Jetted oil toward the bearings and bearing holder cooling oil are recollected through a suction pump into a reservoir, and are fed by a pressurizing pump from the reservoir to the spindle assembly. Oil is there cooled by a cooling device.The circulating oil temperature and oil amount are detected by sensors to be observed.