An integrated spindle and motor unit includes a housing containing both the spindle shaft and motor with hydrostatic bearings around the front and rear of the spindle shaft. The hydrostatic bearings utilize high pressure oil, preferably in the range of 1,200-1,500 psi and provide good load bearing capacity...http://www.google.fr/patents/US5921731?utm_source=gb-gplus-shareBrevet US5921731 - High speed hydrostatic spindle
