Bearing apparatus

Abstract

A bearing is mounted to a hollow shaft provided to a hub wheel. A shaft end of the hollow shaft is deformed radially outward and caulked to an outer end face of an inner ring of the bearing. Between a first area in which a spline portion is formed and a second area in which a caulked portion is formed between a bending starting point for bending the shaft end radially outward and an end face of the shaft end on an inner peripheral face of the hollow shaft, a third area for suppressing deformation of the inner peripheral face of the hollow shaft caused by the caulking is formed. The third area cushions deformation in the first area.

What is claimed is:  
     
         1 . A bearing apparatus comprising: 
 a hollow shaft body; and    a rolling bearing mounted to an outer peripheral face of said shaft body, wherein    a shaft end of said shaft body is deformed radially outward and caulked to an outer end face of an inner ring provided to said rolling bearing, and    said shaft body has on an inner peripheral face thereof a first area in which a spline portion in an axial direction is formed, a second area between a bending starting point for bending said shaft end of said shaft body radially outward and an end face of said shaft body, and a third area between said first area and said second area for suppressing deformation of said inner peripheral face of said shaft body caused by said caulking.    
     
     
         2 . The bearing apparatus according to  claim 1 , wherein said rolling bearing is a double row angular contact ball bearing with vertex of contact angles outside of bearing.  
     
     
         3 . The bearing apparatus according to  claim 1 , wherein said third area is set according to the following expression (1): 
       ( X 1 /X 2)>( y 1 /y 2)  (1) 
       where 
 X1 is an axial distance from a position of a caulking side end portion of said first area to said bending starting point for bending said shaft end of said shaft body radially outward,  
 X2 is an axial distance from said bending starting point to a caulking side outer end face of said inner ring,  
 y1 is a difference between an outside diameter and a pitch diameter of said first area, and  
 y2 is a difference between an outside diameter and an inside diameter of said shaft end of said shaft body.  
 
     
     
         4 . A bearing apparatus according to  claim 3 , wherein an inner peripheral edge portion of a caulking side outer end face of said inner ring is chamfered with a quarter of a circumference of a radius of curvature from a center and a point of intersection of a radial line from said center and said inner peripheral edge portion is said bending starting point.  
     
     
         5 . A vehicle hub unit comprising a hub wheel and a double row angular contact ball bearing with vertex of contact angles outside of baring, wherein 
 said hub wheel includes a hollow shaft body in which a drive shaft of a vehicle is inserted, said shaft body including a small-diameter outer peripheral face and a large-diameter outer peripheral face,    said angular contact ball bearing includes a first inner ring having a single race fitted over said small-diameter outer peripheral face of said shaft body, a single outer ring having two rows of races, a plurality of balls disposed in two rows, and a second inner ring having two cages and formed of said large-diameter outer peripheral face of said hollow shaft, and    said shaft body has a shaft end deformed radially outward and caulked to an outer end face of said inner ring of said angular contact ball bearing and has on an inner peripheral face thereof a first area in which a spline portion in an axial direction is formed, a second area between a bending starting point for bending said shaft end of said shaft body radially outward and an end face of said shaft body, and a third area between said first area and said second area for suppressing deformation of said inner peripheral face of said shaft body caused by said caulking    
     
     
         6 . The vehicle hub unit according to  claim 5 , wherein said third area is set according to the following expression (1): 
       ( X 1 /X 2)>( y 1 /y 2)  (1) 
       where 
 X1 is an axial distance from a position of a caulking side end portion of said first area to said bending starting point for bending said shaft end of said shaft body radially outward,  
 X2 is an axial distance from said bending starting point to a caulking side outer end face of said first inner ring,  
 y1 is a difference between an outside diameter and a pitch diameter of said first area, and  
 y2 is a difference between an outside diameter and an inside diameter of said shaft end of said shaft body.  
 
     
     
         7 . The vehicle hub unit according to  claim 6 , wherein an inner peripheral edge portion of said caulking side outer end face of said first inner ring is chamfered with a quarter of a circumference of a radius of curvature from a center and a point of intersection of a radial line from said center and said inner peripheral edge portion is said bending starting point.