This Note proposes a novel radial-thrust combo metal mesh foil bearing (MMFB). Although MMFBs have advantages such as higher stiffness and damping over conventional air foil bearings, studies related to MMFBs have been limited to radial MMFBs. The novel combo MMFB is composed of a radial top foil, thrust top foils, and a ring-shaped metal mesh damper--fabricated by compressing a copper wire mesh--with metal mesh thrust pads for the thrust bearing at both side faces. In this study, the combo MMFB was fabricated in half-split type to support the rotor for a micro gas turbine generator. The manufacture and assembly process for the half-split-type combo MMFB is presented. In addition, to verify the proposed combo MMFB, motoring test results up to 250,000 rpm and axial displacements as a function of rotational speed are presented.

Most of spindles for machine tool are supported by ball bearings, and there are problems in the limits of high speed and high power as well as the cumbersome maintenance due to the short life time. In order to overcome these problems of the conventional spindles, the high speed spindle with magnetic bearings is developed in this study. Magnetic bearings for 60 000 r/min class high-speed spindle are designed, and high speed spindle with magnetic bearings are fabricated. Based on the running test up to 60 000 r/min, it is verified that the spindle is stably supported by the magnetic bearings, and the magnitude of the unbalance response at 60 000 r/min is less than 3 μm.

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