Hybrid fluid bearing with stiffness modified by electromagnetic effect

Claim 1

A hybrid fluid bearing for a rotary shaft subjected to radial loads, the bearing comprising: a fixed body; a tubular part mounted inside the fixed body and having an internal bore which defines a cylindrical bearing surface that leaves a small basic clearance about the shaft; a series of recesses formed in said cylindrical bearing surface, said recesses being distributed around the circumference of the tubular part; means for feeding the recesses with fluid and for evacuating fluid from the recesses; and sealing means formed between the tubular part and the shaft on either side of that portion of the tubular part which has said recesses; wherein said tubular part is made of a nonmetallic material and has a thickness lying between about 1.5 mm and about 3 mm; wherein the rotary shaft is provided with an annular magnetic circuit constituted by trued-up laminations which extend axially over at least a portion of the peripheral zone of the shaft facing the recesses provided in the tubular part; wherein a fixed magnetic circuit constituted by a stack of laminations defines a series of poles and notches and is mounted concentrically about the tubular part on the opposite side thereof from its bearing surface, and extends axially over the zone to the shaft which is provided with said annular magnetic circuit; and wherein electromagnetic windings are disposed in said notches around said poles of the fixed magnetic circuit and are fed from servocontrol loops which receive signals from at least one vibration detector disposed on said fixed body and in the vicinity of the bearing.