Optimization of groove dimensions in herringbone-grooved journal bearings for improved repeatable run-out characteristics

Optimization of groove dimensions in herringbone-grooved journal bearings is discussed in this paper with aims to design precision spindles with improved run-out characteristics. An evaluation index to represent the magnitude of the amplitude of repeatable run-out is firstly introduced and the groove design parameters are theoretically discussed to minimize the index value with taking the stable operation condition of the bearing into account. The comprehensive parameter research reveals a guideline for the design of the groove configuration for good run-out characteristics. Experiments with a shaft with grooves designed along the proposed guideline show that the amplitude of repeatable run-out reduces to about half of that of a bearing with currently designed groove configurations, thus confirming validity of the above guideline.