摘要 |
A bearing structure, preferably for supporting a rotary table (4) in metrological apparatus, includes both a journal bearing (34,36,38) and a thrust bearing (56,66). The journal bearing is made up of three dry pads (34,36,38), one (38) of which is radially adjustable, and the thrust bearing (56,66) comprises first and second air bearings. The axis of rotation of the bearing is vertical, and the lower (66) of the air bearings is less stiff than the upper one (56). |