Wheel Support Bearing Assembly and Method of Manufacturing the Same

Abstract

To provide a wheel support bearing assembly, which is effective to avoid an inner race detachment during assemblage onto an automotive vehicle. The assembly is provided with an inner member made up of a hub axle and an inner race mounted on an outer periphery of an inboard end portion of the hub axle. The inner race has an inner periphery provided with an stepped area that extends to an inboard annular face of the inner race and has a depth measured at an inner peripheral edge of an inboard annular face, and an inner surface of this stepped area is of a shape made up of a straight area and an inclined surface continued from an outboard end of the straight area to the inner peripheral surface, and a plastically deformed portion engageable with the inclined surface as a result of crimping is provided in the hub axle.

1 . A wheel support bearing assembly for rotatably supporting a vehicle drive wheel, which comprises:
 an outer member having an inner periphery formed with a double row of raceway surfaces, an inner member having raceway surfaces formed therein and opposite to those raceway surfaces in the outer member, and a double row of rolling elements each row interposed between the respective raceway surfaces in the outer and inner members;   the inner member being made up of a hub axle, having a wheel mounting hub flange formed in an outer periphery thereof and also having a center bore, and an inner race segment mounted on an outer periphery of an inboard end portion of the hub axle, with the raceway surfaces being defined respectively in the hub axle and the inner race segment;   the inner race segment having an inner peripheral surface provided with an annular stepped area that extends to an inboard end face of the inner race segment and has a depth defined at an inner peripheral edge of an inboard end face of the inner race segment, the annular stepped area being of a shape made up of a straight area portion in the form of a cylindrical surface and an inclined surface portion continued from an outboard end of the straight area portion to the inner peripheral surface of the inner race segment, and a plastically deformed portion engageable with the inclined surface portion of the annular stepped area in the inner race segment as a result of crimping of the hub axle being provided in the hub axle.   
   
   
       2 . The wheel support bearing assembly for rotatably supporting the vehicle drive wheel as claimed in  claim 1 , wherein the plastically deformed portion is a portion crimped in a diametric expanded condition by pressing a crimping punch, having a free end portion outer peripheral surface that is tapered, into an inner periphery of the inboard end portion of the hub axle. 
   
   
       3 . The wheel support bearing assembly for rotatably supporting the vehicle drive wheel as claimed in  claim 2 , wherein the inclined surface portion is a tapered surface and the plastically deformed portion does not protrude outwardly beyond the end face of the inner race segment and does not contact the straight area portion of the stepped area. 
   
   
       4 . The wheel support bearing assembly for rotatably supporting the vehicle drive wheel as claimed in  claim 2 , wherein the plastically deformed portion does not protrude outwardly beyond the end face of the inner race segment and the crimping punch has a corner delimited between the tapered surface and a free end face thereof, which is chamfered. 
   
   
       5 . The wheel support bearing assembly for rotatably supporting the vehicle drive wheel as claimed in  claim 1 , wherein the plastically deformed portion does not protrude outwardly beyond the end face of the inner race segment; a hub axle mounting surface, which is an inner diametric surface portion continued from the stepped area in the inner race segment, is rendered to be a ground surface; and a transit portion between the hub axle mounting surface and the inclined surface portion of the stepped area is of a sharp corner shape. 
   
   
       6 . The wheel support bearing assembly for rotatably supporting the vehicle driven wheel as claimed in  claim 2 , wherein a surface of the plastically deformed portion, which contacts the crimping punch, is applied with a lubricant. 
   
   
       7 . A method of manufacturing a wheel support bearing assembly, which comprises
 an outer member having an inner periphery formed with a double row of raceway surfaces, an inner member having raceway surfaces formed therein and opposite to those raceway surfaces in the outer member, and a double row of rolling elements each row interposed between the respective raceway surfaces in the outer and inner members;   the inner member being made up of a hub axle, having a wheel mounting hub flange formed in an outer periphery thereof and also having a center bore, and an inner race segment mounted on an outer periphery of an inboard end portion of the hub axle;   the hub axle and the inner race segment being formed with the rows of the raceway surfaces, respectively; and   the inner race segment having an inner peripheral surface provided with an annular stepped area that extends to an inboard end of the inner race segment and has a depth defined at an inner peripheral edge of an inboard end face of the inner race segment, the annular stepped area being of a shape made up of a straight area portion in the form of a cylindrical surface and an inclined surface portion continued from an outboard end of the straight area portion to the inner peripheral surface of the inner race segment, and a plastically deformed portion engageable with the inclined surface portion of the annular stepped area in the inner race segment as a result of crimping of the hub axle being provided in the hub axle; and in which method:   the plastically deformed portion, being of a cylindrical configuration before it is deformed, being formed by pressing a crimping punch, of which front end portion outer peripheral surface is a tapered shape, axially into an inner peripheral surface of the inboard end portion of the hub axle to allow the cylindrical plastically deformed portion to be crimped in the diameter expanded condition.   
   
   
       8 . The method of manufacturing the wheel support bearing assembly as claimed in  claim 7 , further comprising adjusting an axial stroke, over which the crimping punch is pressed, to adjust an outer diameter of the plastically deformed portion after crimping has been carried out. 
   
   
       9 . The method of manufacturing the wheel support bearing assembly as claimed in  claim 7 , further comprising applying a lubricant oil, before the crimping is performed with the crimping punch, to one or both of an inner peripheral surface of the cylindrical plastically deformed portion of the hub axle and the front end portion outer periphery of the crimping punch, the crimping being performed in a lubricant applied condition. 
   
   
       10 . The method of manufacturing the wheel support bearing assembly as claimed in  claim 7 , wherein the crimping punch has a corner delimited between the tapered surface and a free end face, which corner is chamfered.