高周波外力の作用下におけるポケット付きオリフィス絞りを有す戸静圧気体ジャーナル軸受の応答特性

概要

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Recently, gas bearings have been used in high speed spindles and in ultra precision cutting machines. It is known that the bearing performances are defined in stiffness and damping, and when the disturbance force acts on the shaft, the shaft response is predicted by damping factors of the bearing system and frequency ratio. In this paper, the journal center locus is measured in two cases : one is when the radial and the tangential electromagnetic forces act on the shaft twice and the other, four times, at every rotational cycle time at 10OOO rpm and 30OOO rpm, and theoretical calculations and experimental results are compared. Following conclusions are obtained : (1) the time of shaft convergence is shorter under low supply pressure than under high supply pressure. (2) The amplitude of shaft vibration becomes small when frequency ratio is greater than 2-3. (3) When high frequency external forces act on the shaft at every rotational cycle time, if the radial damping factor (ξ_r) gets to over O.3 and the tangential damping factor (ξ_t ) over O.5,the shaft comes to the steady state within 2-3 periods of rotational cycle time at 30OOO rpm.
公益社団法人精密工学会の論文
1990-05-05