JPS6434602A - Spindle support device - Google Patents

Abstract

PURPOSE:To preload a bearing properly and with good responsiveness, and enable the control of a preload level accurately by providing a piezoelectric element or an electrostrictive element at both sides of at least one of two bearings and causing the reciprocating motion of one bearing in an axial direction via the operation of said element. CONSTITUTION:Angular contact ball bearings 3 and 4 are fixed to a spindle 2 and a housing 5. The inner races of angular contact ball bearings 8 and 9 are fixed to the spindle 2 and the outer races thereof are made in contact with the housing 5 and a rear cover 14 in such a way as to reciprocate in an axial direction via the first and second piezoelectric elements 12 and 13. The speed of the spindle 2 is detected with a sensor, the applied voltage of the piezoelectric elements 12 and 13 is changed and a preload level working upon the angular contact ball bearings 8 and 9 is adjusted. It becomes possible, therefore, to transmit a preload level corresponding to the number of revolutions to the bearings properly and improve responsiveness via a simple constitution, thereby enabling the quick and proper adjustment of the preload level against the occurrence of an external force.