Double row ball bearing

Abstract

In a state where the axes of an inner race 20 and an outer race 30 are inclined with respect to each other, the maximum value of a clearance between the ball-fitting-direction rearward side edge portion of the second inner race raceway 22 of the inner race 20 and the ball-fitting-direction rearward side edge portion of the second outer race raceway 32 of the outer race 30 is larger than the diameter of the respective balls belonging to the second ball row. Also, the maximum value of a clearance between the ball-fitting-direction forward side edge portion of the second inner race raceway 22 of the inner race 20 and the second outer race raceway 32 edge portion on the upper side peripheral surface 33 of the outer race 30 is smaller than the diameter of the respective balls belonging to the second ball row.

What is claimed is:  
     
         1 . A double row ball bearing comprising: 
 an inner race defining first and second inner race raceways respectively formed on the outer peripheral surface thereof;    an outer race defining first and second outer race raceways respectively formed on the inner peripheral surface thereof and corresponding to said first and second inner race raceways of said inner race, said outer race being to be mounted onto said inner race;    first and second raceways respectively defined between said inner race and said outer race mounted on said inner race by said mutually corresponding inner race raceways and outer race raceways of said inner race and said outer race;    a first ball row including a plurality of balls being rollably fittable into said first raceway before said outer race is mounted onto said inner race;    a first retainer inserted into said first raceway together with said first ball row;    a second ball row including a plurality of balls rollably fittable into said second raceway after said outer race is mounted onto said inner race; and,    a second retainer inserted into said second raceway together with said second ball row,    wherein, when said balls of said second ball row are respectively fitted into said second raceway in a state where the axes of said inner race and said outer race are inclined with respect to each other, the maximum value of a first clearance between a ball-fitting-direction rearward side edge portion of said second inner race raceway of said inner race forming said second raceway and a ball-fitting-direction rearward side edge portion of said second outer race raceway of said outer race forming said second raceway is larger than the outer diameter of said each ball of said second ball row, and the maximum value of a second clearance between a ball-fitting-direction forward side edge portion of said second inner race raceway of said inner race forming said second raceway and a ball-fitting-direction forward side edge portion of said second outer race raceway of said outer race forming said second raceway is smaller than the outer diameter of said each ball of said second ball row.    
     
     
         2 . The double row ball bearing according to  claim 1 , wherein a dimension along the radial direction of said outer race between a bottom portion of said second outer race raceway of said outer race and the ball-fitting-direction forward side edge portion of said second race raceway is equal to or larger than 20% of the outer diameter of said ball of said second ball row.  
     
     
         3 . The double row ball bearing according to  claim 1 , wherein said balls of said second ball row have the same outer diameter as that of said balls of said first ball row.  
     
     
         4 . The double row ball bearing according to  claim 1 , wherein said balls of said second ball row are smaller in number than that of said first ball row.