Manufacturing method of rotating element, connecting structure between rotating element and rotating shaft, and steering apparatus
View Patent ↗A manufacturing method of a rotating element including a cylindrical fitting portion having a pair of circumferential end portions forming an axial slit between the circumferential end portions, the cylindrical fitting portion being serration-fitted to a rotating shaft, includes: clamping the fitting portion by a clamp jig so that the fitting portion is elastically deformed in an elliptical shape; forming a female serration arranged in an elliptical shape by use of a tool having an elliptical section, the female serration being formed on an inner peripheral surface of the fitting portion elastically deformed in the elliptical shape; and releasing the clamping by the clamp jig so that the arrangement of the female serration is changed to a perfect-circle shape from the elliptical shape.
1. A manufacturing method of a rotating element including a cylindrical fitting portion having a pair of circumferential end portions forming an axial slit between the circumferential end portions, the cylindrical fitting portion being serration-fitted to a rotating shaft, the manufacturing method comprising:
clamping the fitting portion by a clamp jig so that the fitting portion is elastically deformed in an elliptical shape that is flat in a predetermined radial direction toward the axial slit;
forming a female serration arranged in an elliptical shape by use of a tool having an elliptical section with a short diameter in the predetermined radial direction, the female serration being formed on an inner peripheral surface of the fitting portion clamped by the clamp jig so as to be elastically deformed in the elliptical shape; and
releasing the clamping by the clamp jig so that the arrangement of the female serration is changed to a perfect-circle shape from the elliptical shape.
2. The manufacturing method according to claim 1 , wherein:
a difference between a long diameter and a short diameter of an ellipse formed by the inner peripheral surface of the fitting portion clamped by the clamp jig is equal to a difference between a long diameter and a short diameter of an ellipse formed by the tool.
3. The manufacturing method according to claim 1 , wherein
the difference between the long diameter and the short diameter of the ellipse formed by the tool is larger than a deviation amount of the difference between the long diameter and the short diameter of the ellipse formed by the inner peripheral surface of the fitting portion clamped by the clamp jig.