Asmo Co., Ltd.

Koji Kidowaki

Takayoshi Sasaki

Masanori Takeuchi

Keiji Inoue

Nobuyuki Matsumoto

Toshikatsu Nakashima

In a forging process step, a small diameter portionis formed in the leading end portion of a cylindrical shaft material, and an installation depressed portionis formed on a base end face of the shaft materialfor installing a balltherein to receive thrust force, by cold forging process using a forging mold. In a worm forming process after the forging process step, a wormis formed in the small diameter portionby rolled dies. The small diameter portionand the installation depressed portionare formed by cold forging process, so that an outer circumferential face of the small diameter portionand an inner face of the installation depressed portionbecome even surfaces with small surface roughness.

Manufacturing method of armature shaft, armature shaft and rotary electric machine

An object of the present invention is to provide a method of manufacturing a rotational shaft having a worm, wherein a worm portion has a small bending amount. According to the method of the invention, a worm portion is formed at a worm forming portion by a rolling process with rolling dies, and a small diameter portion is formed at least at one axial end of the worm forming portion, wherein a diameter of the small diameter portion is smaller than a diameter of a bottom of a worm tooth to be formed at the worm forming portion, so that surplus material portion of the worm forming portion can flow toward the small diameter portion.

Method for manufacturing a worm shaft

An apparatus manufactures a die for rolling an hourglass worm in improved processing accuracy. The apparatus includes a swing table swung, a movement table mounted on the swing table, and a workpiece shaft arranged on the movement table. The axis of a disk-shaped workpiece is perpendicular to a swing axis of the swing table. The workpiece includes a peripheral surface with a cross-section extending along the workpiece axis and defining an arc substantially identical to the arc of the root surface of the hourglass worm. The movement table is arranged so that the swing axis of the swing table extends through a center of curvature of the arc defined on the peripheral surface of the workpiece. A synchronization mechanism swings the swing table in synchronism with the rotation of the workpiece shaft.

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Toyohashi, Japan

Koji Kidowaki