| 摘要 |
PROBLEM TO BE SOLVED: To continuously achieve the form rolling of a plurality of groove parts by turnably and reciprocally providing a ball holding member to support a form rolling ball mounted in a guide hole of a tool shaft in a projecting manner to easily return the ball holding member to the initial position. SOLUTION: Form rolling balls 4 are rotatably inserted in a plurality of guide holes 3 radially pierced in a circumferential wall part of an approximately cylindrical tool shaft 1. An approximately cylindrical ball holding member 5 is provided in a hollow part of the tool shaft 1 turnably around the axis, and reciprocally in the axial direction to hold the form rolling balls 4 in a projecting manner, and the clearanceγin the radial direction from the tool shaft 1 is set to be larger than the depthδof a machined groove by the form rolling balls 4. The ball holding member 5 is supported by a point-contact connection balls 7, 8 provided in the longitudinal direction, and energized in the axial direction opposite to the advancing direction of the tool shaft 1 by a coil spring 9. The ball holding member 5 which is advanced during the form rolling of the groove is energized after completion of machining, and automatically returned to the original position.
|
