Effect of alignment errors on operation of machine tool spindle with active bearing preloading module

Abstract

The article describes a test stand with a spindle equipped with an active bearing preload system using piezoelectric actuators. The proper functioning of the spindle and the active system was associated with the correct alignment of the spindle shaft and the drive motor. The article presents two methods of shaft alignment. The use of commonly known shaft alignment methods with dial indicators is insufficient from the viewpoint of being able to control this preload. This work aims at making the readers awarethat,forsystemswithactivebearingpreload,thelatestmeasuringdevicesshouldbeusedtoaligntheshaft.Theuseofcommonlyknownmethodsofequalizationwithdialgaugesisinsufficientfromthepointofviewofcontrollingthispreload.Increasingtheaccuracyofshaftalignmentfrom0.1to0.01mmmadeitpossibletoobtaina50%reductioninthedisplacementoftheouterbearingringduringspindleoperation.