Rolling die for ball screw
AssigneeNsk Ltd.
InventorsEtsuo Koike, Hitoshi Sannomiya
Life of this patent
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Abstract
A rolling die for a ball screw has: a cylindrical portion including a helical protrusion formed in an outer peripheral surface thereof for forming a helical ball groove in a raw material of a screw shaft of the ball screw; and a conical lead-in portion formed in one end portion of the cylindrical portion, the lead-in portion including a plurality of frustum-cone-shaped portions, wherein the contact angles of the frustum-cone-shaped portions with respect to the raw material of the screw shaft are each set so as to increase sequentially in the order starting at and from the frustum-cone-shaped portion adjoining the cylindrical portion.
Claims5
A rolling die for a ball screw, comprising:
- a cylindrical portion including a helical protrusion formed in an outer peripheral surface thereof for forming a helical ball groove in a raw material of a screw shaft of the ball screw;
- and
- a conical lead-in portion formed in one end portion of the cylindrical portion, the lead-in portion including a plurality of frustum-cone-shaped portions,
- wherein the contact angles of the frustum-cone-shaped portions with respect to the raw material of the screw shaft are each set so as to increase sequentially in the order starting at and from the frustum-cone-shaped portion adjoining the cylindrical portion.
Dependencies are inferred from the claim text.