Optimization of Groove Dimensions in Spiral-Grooved Journal Bearings for RRO or NRRO Characteristics

Spiral-grooved bearings have recently attracted large attention for spindles of precision equipment. In this paper, optimizing the groove dimensions of spiral-grooved journal bearings for RRO or NRRO characteristics is discussed. Evaluation indexes for operating bearings concerning the static displacement of the rotor and RRO and NRRO amplitudes are firstly proposed. The appropriate groove designs (groove width, angle, and depth) for minimizing the proposed evaluation indexes are given, and it is also shown that the design can improve bearing run-out performances much more than the currently recommended design. In addition, by separating the optimum groove designs for the two groups, guidelines for designing of the groove configuration for good RRO and NRRO characteristics are comprehensively indicated.