Nsk Corporation

Masahiro Yasumura

Nobuyuki Hagiwara

Shoji Horike

Tatsuya Enomoto

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.

Driving-wheel supporting hub unit and its manufacturing method

To avoid a difficulty of inserting a spline shaft into a spline hole, respective holding membersconstituting a holding devicefor holding a hubare displaced in a radial inward direction of a small diameter stepped portion. The inner peripheral surface of the inside end of an original holeis 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. In this condition, a female spline portion for constituting a spline hole is formed in the original hole

Manufacturing method for a drive wheel rolling bearing unit and manufacturing apparatus therefor

In a manufacturing method and a manufacturing apparatus for a wheel-support rolling bearing unit, when forming a crimped portionon an end (inside end) of a hub main body, by rocking die forging using a die, while preventing enlargement of equipment, in order to prevent forming indentations in a second outer racewayand a second inner raceway, in the present invention, the outer ringis turned by a motor, and the ballsare rotated. A difference is provided between the rotation speed of the ballsand an oscillation speed of the die. This difference is preferably at least 10 min. By rotating the ballsthe formation of indentations in the second outer racewayand the second inner racewayis prevented. Moreover, by providing the difference between the rotation speed and the oscillation speed of the die, an increase in the torque required for rotation the outer ringis suppressed.

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Fujisawa, Japan

Masahiro Yasumura