Apparatus for rolling a cylindrical blank

A rolling apparatus of flat-die type for rolling a cylindrical blank to generate plural teeth on the periphery of the blank, said apparatus comprising:

• a pair of flat dies having shaped rolling faces comprising a plurality of straight teeth running parallel to the width of said rolling faces, said teeth having a profile corresponding to the tooth form of the teeth to be generated on the cylindrical blank, said flat dies being disposed opposite to each other in a manner which permits movement relative to and in parallel to each other, with a distance therebetween selected to permit the cylindrical blank to be brought into pressed rolling engagement with said rolling faces of the flat dies, wherein each of said pair of flat dies comprises a roll-on part located adjacent to one edge of the rolling face thereof on the blank-incoming side of the flat die as viewed in a plane along the width of said rolling face, said roll-on part of said teeth having both top lands at the crests of said teeth and bottom lands between the crests of said teeth inclined with respect to an axis of said cylindrical blank so as to reduce the distance between said rolling faces in a direction in which said blank is fed, the angle of inclination of each said top land being greater than the angle of inclination of each said bottom land;
• a work supporting device for supporting the blank rotatably about its axis such that said axis is perpendicular to the lines of movement of said flat dies and parallel to the planes of said rolling faces, said work supporting device being movable in a direction parallel to said axis of the blank;
• a work in-feeding device for driving said work supporting device to feed the blank axially and push the same between said dies for axially progressive rolling engagement thereof with said rolling faces;
• and
• a flat-die reciprocating device for reciprocating said flat dies relative to each other in opposite directions to roll the blank bidirectionally on said rolling faces of the flat dies in pressed rolling engagement with said rolling faces.