Measured Displacement Coefficients of an Adjustable Hydrodynamic Rotor Journal Bearing

摘要

There is an impetus for improving performance of fluid film bearings whether indicated by stiffness, damping, stability, noise signatures, temperature rises, energy loss etc., aspects previously reported by the authors and others, [1,2,3,4]. A novel form of adjustable fluid film bearing has hydrodynamic characteristics that can be changed in a continuously controlled manner during operation, irrespective of the loading conditions on the bearing, a pro-active characteristic. The principle can be applied to conventionally orientated journal bearings, i.e. shaft rotating; to inverse orientations, i.e. a rotor on a stationary shaft, and to thrust bearings. Investigations have been carried out on theoretical and practical models for journal bearings of both orientations [5,6,7]. This paper concerns potential applications in high-speed machine tools where stability and accuracy are vital, for example in grinding operations. A large rotor was supported on a stationary shaft within which were a pair of hydrodynamic oil film bearings each comprising 4 adjustable surface segments. Figure 1 shows the shaft, Fig. 2 shows a cross section of one bearing with adjuster segments, G1 - G4 (displacements greatly exaggerated). Loads were applied to the rotor by large external non-contacting electro-magnets, [8]. Some aspects of performance as measured in tests are presented.