| 摘要 |
PURPOSE:To reduce a diameter of housing and minimize the whole unit by forming three or more of axial air supply grooves which introduce compressed supplied air through an air supply throttle port to a journal bearing face on an outer peripheral surface of a bearing sleeve, also forming axial exhaust grooves which introduce exhaust gas from each journal bearing surface outside, and providing a plurality of air supply throttle ports and exhaust ports on the air supply and exhaust grooves. CONSTITUTION:Compressed air supplied from an air supply introducing port 11 is branched into branched flow passages 111 to 114 and introduced into air supply throttle ports 7, 7', 7''. Axial air supply grooves 5 are formed on an outer periphery of a bearing sleeve 6, so that a sectional area of a main housing 4 is decreased and size and weight of a static pressure air bearing spindle are reduced. A main shaft 2 is rotated under a non-contact condition with the bearing sleeve 6 by the compressed air supplied from the air supply throttle port 7, and the exhaust gas thereof is discharged through an exhaust port 9 from axial exhaust grooves 10. A plurality of axial grooves 5, 10 are formed and sectional shapes thereof are set rectangularly, thereby passages having wide sectional areas are secured. The exhaust grooves 10 are formed in an axial direction from a spindle end, then foreign material is hard to exist between gaps of bearings. |
