Preloading method for preload-adjustable rolling bearing and manufacture of the same

Abstract

An assembly method of a preload-adjustable rolling bearing unit comprising the steps of providing a shaft having a first inner raceway, an inner ring being press fitted onto the shaft and having a second inner raceway, such that a pitch of both raceways is set greater than a pitch required to give a predetermined preload, providing an outer ring having outer raceways, providing a plurality of balls to be fitted between the outer raceways of the outer ring, and the first and second inner raceways, positioning the balls equidistant apart in the circumferential direction, and vibrating the rolling bearing unit by means of piezo electric elements while moving the inner ring in the axial direction, measuring the resonant frequency of the rolling bearing unit with a vibration sensor to control the preload whereby the inner ring is pressed onto a shaft while vibrating with only a small amount of energy without scratching the raceway and rolling surfaces.

1 - 75 . (canceled)  
     
     
         76 . A preloaded, double row bearing unit comprising: 
 an outer ring having a first outer raceway and a second outer raceway,    a shaft member formed with a first inner raceway,    an inner ring formed with a second inner raceway,    a first row of tapered rollers provided between the first outer raceway and the first inner raceway, and    a second row of tapered rollers provided between the second outer raceway and the second inner raceway,    wherein the bearing unit has been preloaded, by way of pressure-fitting between the shaft member and the inner ring, by pushing the inner ring which is tightly fitted to the shaft member to preload the bearing unit by utilizing interference which produces a larger friction force than the force of the preload, and    wherein, provided that D is a diameter of a pitch circle defined by the tapered rollers of the first and second rows of tapered rollers and P is a pitch in the axial direction of the outer ring and shaft member in the first row of tapered rollers and the second row of tapered rollers, D>P.