Abstract: When an inner ring of a driving-wheel supporting hub unit is fixed to a hub, a pressing die is displaced downward and an annular working surface at a lower end surface of the pressing die is pressed against a front end of a cylindrical portion over its whole periphery. Further, in this state, the pressing die is pressed downward toward the hub without rocking the pressing die relative to the hub. Thus, the cylindrical portion is plastically deformed radially outward along the working surface simultaneously over its whole periphery. By adopting this method, the operation of plastically deforming the cylindrical portion at the inner end of the hub to form a caulking portion, can be easily and performed accurately. Accordingly, the structure of the caulking portion forming apparatus can be simplified.

Abstract: To avoid a difficulty of inserting a spline shaft into a spline hole, respective holding members 29 constituting a holding device 28 for holding a hub 3 are displaced in a radial inward direction of a small diameter stepped portion 15. The inner peripheral surface of the inside end of an original hole 25 is elastically deformed radially inward the same as or slightly greater than the elastic deformation caused by externally securing tightly an inner ring to the small diameter stepped portion 15. In this condition, a female spline portion for constituting a spline hole is formed in the original hole 25.

Abstract: When an inner ring 3 of a driving-wheel supporting hub unit is fixed to a hub 2, a pressing die 24 is displaced downward and an annular working surface 27 at a lower end surface of the pressing die 24 is pressed against a front end of a cylindrical portion 13a over its whole periphery. Further, in this state, the pressing die 24 is pressed downward toward the hub 2 without rocking the pressing die 24 relative to the hub 2. Thus, the cylindrical portion 13a is plastically deformed radially outward along the working surface 27 simultaneously over its whole periphery. By adopting this method, the operation of plastically deforming the cylindrical portion 13a at the inner end of the hub 2 to form a caulking portion, can be easily and performed accurately. Accordingly, the structure of the caulking portion forming apparatus 21 can be simplified.

Abstract: Upon assembling a hub unit, an inner race element is press-fitted onto a small diameter stepped portion of the hub, and thereafter an inner periphery of an axially extended hole of the hub is subjected to broaching to form a female serration extended in the axial direction, thereby providing a complete product.

Abstract: In a manufacturing method and a manufacturing apparatus for a wheel-support rolling bearing unit, when forming a crimped portion 14 on an end (inside end) of a hub main body 8a, by rocking die forging using a die 26, while preventing enlargement of equipment, in order to prevent forming indentations in a second outer raceway 6a and a second inner raceway 12a, in the present invention, the outer ring 1a is turned by a motor 48, and the balls 32 are rotated. A difference is provided between the rotation speed of the balls 32 and an oscillation speed of the die 26. This difference is preferably at least 10 min?1. By rotating the balls 32 the formation of indentations in the second outer raceway 6a and the second inner raceway 12a is prevented. Moreover, by providing the difference between the rotation speed and the oscillation speed of the die 26, an increase in the torque required for rotation the outer ring 1a is suppressed.

Abstract: In a method of processing a female spline of a hub unit for supporting a wheel, a hole 3a which is formed to be cylindrical is provided on a shaft portion 3c of a hub unit 103 before plastically deforming by caulking (or clinching), and after the plastically deforming by caulking (or clinching), a female spline is formed on the hole 3a by semi-dry or dry broaching. The hole 3a which is formed to be cylindrical after plastically deforming by caulking (or clinching) has the form that the size is greater at a portion nearer a portion 3d plastically deforming by caulking (or clinching) of the shaft portion 3c for an estimated amount of contraction caused by the plastically deforming by caulking (or clinching) or the press-fitting of an inner race element.

Abstract: It's an object of the invention to precisely match a mounting surface 14 of a mounting flange 13 for fixedly supporting a rotor, with a virtual plane perpendicular to the rotation axis of a hub 8b, to thereby prevent judder which occurs at the time of braking. For that purpose, a processing jig is pressed into the inner peripheral surface of an unfinished hole formed in the mounting flange 13 to form female serrations and make mounting holes 15, after which the mounting surface 14 is subjected to finishing. Then a male serration portion 16 of a stud 9 is loosely fitted into the mounting hole 15. As a result, deterioration of the accuracy of the mounting surface 14 accompanying fitting of the male serration portion 16 can be prevented.

Abstract: To avoid a difficulty of inserting a spline shaft into a spline hole, respective holding members 29 constituting a holding device 28 for holding a hub 3 are displaced in a radial inward direction of a small diameter stepped portion 15. The inner peripheral surface of the inside end of an original hole 25 is elastically deformed radially inward the same as or slightly greater than the elastic deformation caused by externally securing tightly an inner ring to the small diameter stepped portion 15. In this condition, a female spline portion for constituting a spline hole is formed in the original hole 25.

Abstract: In a manufacturing method and a manufacturing apparatus for a wheel-support rolling bearing unit, when forming a crimped portion 14 on an end (inside end) of a hub main body 8a, by rocking die forging using a die 26, while preventing enlargement of equipment, in order to prevent forming indentations in a second outer raceway 6a and a second inner raceway 12a, in the present invention, the outer ring 1a is turned by a motor 48, and the balls 32 are rotated. A difference is provided between the rotation speed of the balls 32 and an oscillation speed of the die 26. This difference is preferably at least 10 min?1. By rotating the balls 32 the formation of indentations in the second outer raceway 6a and the second inner raceway 12a is prevented. Moreover, by providing the difference between the rotation speed and the oscillation speed of the die 26, an increase in the torque required for rotation the outer ring 1a is suppressed.