To maintain the accuracy of a rotary shaft highly by installing an electrostatic chuck on the rotary shaft supported in a noncontact state by a static pressure gas bearing and supplying a current in noncontact from an outer electric source to the electrode of the electrostatic chuck.
In this spindle, an insulated anode side discharge member 25 and cathode side discharge member 26 are provided in a housing 1. The high pressure direct current electric source 27 of a housing 1 outside is connected between respective discharge members 25, 26 and a rotary shaft 4 is constituted by the combination of a mutually insulated anode shaft part 7 with a cathode shaft part 8. The anode side discharge surface 28 and cathode side discharge surface 29 faced to the anode side discharge member 25 and cathode side discharge member 26 respectively with the minute clearance are provided on these respective shaft parts. An electrostatic chuck 33 having positive/negative electrodes 35, 36 conducted to the anode shaft part 7 and cathode shaft part 8 is installed on the tip of this rotary shaft 4 and by the discharge current flowing between respective discharge members 25, 26 and respective discharge surfaces 28, 29, the current is supplied between the positive/negative electrodes 35, 36.
ASAHARA AKINOBU
FUJII SHOJI
ITO TAKANOBU
