Rolling Bearing

Abstract

When a minimum thickness h of a part where an outer ring raceway is provided on a middle portion in the axial direction of an outer ring and a diameter Da of each rolling element satisfy the relationship 0.4Da≦h 0.8Da, even when the outer ring is fixed in a transmission case of low-rigidity, elastic deformation of the outer ring can be prevented without increasing the thickness of the outer ring. When an outer diameter D of an outer ring, a width W of this outer ring in the axial direction, a minimum thickness h of a part where the outer ring raceway is provided on a middle portion in the axial direction of the outer ring, and a diameter Da of each ball are controlled such that a value K calculated by {(h 1.5 ·W)/(Da 1.1 ·D 0.5 )} satisfies the relationship 1.20≦K≦2.00, sufficient rigidity of the outer ring can be maintained, and premature flaking based on elastic deformation of the outer ring can be prevented without needlessly increasing the size of the outer ring.

What is claimed is: 
     
         1 . An automobile belt-type continuously variable transmission comprising:
 an input rotating shaft;   an output rotating shaft,   a transmission case;   rolling bearings that rotatably support the input rotating shaft and the output rotating shaft within the transmission case;   a drive pulley provided in the middle portion of the input rotating shaft;   a driven pulley provided in the middle portion of the output rotating shaft; and   an endless belt spanned between the drive pulley and the driven pulley;   each of the rolling bearings comprising:   an outer ring foamed with an outer ring raceway on an inner peripheral surface and fixed to an inside of part of the transmission case;   an inner ring formed with an inner ring raceway on an outer peripheral surface and fixed on an outside of the input rotating shaft or the output rotating shaft; and   a plurality of rolling elements rotatably provided between the inner ring raceway and the outer ring raceway,   wherein the transmission case is made from aluminum alloy,   wherein a lubricant is provided which lubricates rolling contact portions of the rolling bearing,   wherein the lubricant is a continuously variable transmission (CVT) fluid having a kinetic viscosity of 10 mm 2  per second or less at 100° C.,   wherein, when an outer diameter in millimeters of the outer ring is D, a width of the outer ring in the axial direction in millimeters is W, a minimum thickness in millimeters of a part where the outer ring raceway is provided on a middle portion in the axial direction of the outer ring is h, and a diameter in millimeters of each rolling element is Da, the relationship 1.31≦{(h 1.5 ·W)/(Da 1.1 ·D 0.5 )}≦2.00 is satisfied, and   wherein upon attachment to the transmission case made from aluminum alloy, satisfaction of the relationship substantially prevents creep of the outer ring in a same direction as rotation of the inner ring that otherwise occurs due to a localized increase in surface pressure between the outer ring and the transmission case.   
     
     
         2 . An automobile belt-type continuously variable transmission of  claim 1 , wherein the relationship 1.31≦{(h 1.5 ·W)/(Da 1.1 ·D 0.5 )}≦1.51 is satisfied.