| 摘要 |
<p>A back-up bearing (50, Fig. 1) is provided for a magnetic journal or thrust bearing by a source of pressurised fluid 52 (such as gas), channels 51 supplying the fluid to the suspension gap 30 between moving bearing armature 25 and stationary armature pole faces 281, 291, and magnet control means 56 responsive to a decrease in gap width at any point below an acceptable minimum to supply the fluid by way of the channel(s) to the gap to form a hydrostatic bearing between stationary and movable armatures to aid or replace the magnetic bearing support. In a journal bearing, (Fig. 3) in which coil-containing spaces (62) exist between radially extending armature limbs the spaces may be closed by an apertured bridging piece (64) extending between pole faces and fluid supplied via that space to provide both increased hydrostatic bearing area and a means of cooling the coil by a low pressure fluid bleed at all times. The armatures faces may be provided with low friction bearing material to permit rubbing contact at very low speeds or rest. <IMAGE></p> |
