Abstract: When forming a toothed portion on the outer section of a blank by contacting a tooth profile-forming portion of a forming die with a curved portion of the blank, the first projection of the blank is accommodated in a first depression, and a load is applied axially to a center section of the blank so a material of the blank flows radially outward. The material of the blank at the first projection flows in the axial direction to inside the first depression, and the material of the blank at an intermediate section between the center and the outer section flows in axially to inside a second depression to form a second projection. When the load is maximized, a space is provided between a toothed portion and the tooth profile-forming portion, between the first projection and the forming die, and between the second projection and the forming die.

Abstract: A method for manufacturing a toothed part from a cylindrical blank using a forming die. When forming a toothed portion on a radially outer section of the blank by applying a load in the axial direction of the blank to a radially center section of the blank while constraining a portion of an outer circumferential surface of the blank such that a constituent material of the blank flows radially outward, the constituent material of the blank at an intermediate section between the center section and the outer section flows in the axial direction toward a depressed portion of the forming die to form a projection portion. When the load is at maximum, a space is provided between the toothed portion and the forming die, and a space is provided between the projection portion and the forming die.

Abstract: When forming a toothed portion on the outer section of a blank by contacting a tooth profile-forming portion of a forming die with a curved portion of the blank, the first projection of the blank is accommodated in a first depression, and a load is applied axially to a center section of the blank so a material of the blank flows radially outward. The material of the blank at the first projection flows in the axial direction to inside the first depression, and the material of the blank at an intermediate section between the center and the outer section flows in axially to inside a second depression to form a second projection. When the load is maximized, a space is provided between a toothed portion and the tooth profile-forming portion, between the first projection and the forming die, and between the second projection and the forming die.

Abstract: A method for manufacturing a toothed part from a cylindrical blank using a forming die. When forming a toothed portion on a radially outer section of the blank by applying a load in the axial direction of the blank to a radially center section of the blank while constraining a portion of an outer circumferential surface of the blank such that a constituent material of the blank flows radially outward, the constituent material of the blank at an intermediate section between the center section and the outer section flows in the axial direction toward a depressed portion of the forming die to form a projection portion. When the load is at maximum, a space is provided between the toothed portion and the forming die, and a space is provided between the projection portion and the forming die.

Abstract: A workpiece 20b is formed that includes a circular bottom portion 22b having a hole 23b and an inner wall portion 24b around the hole 23b, and a skirt-shaped outer wall portion 25b that includes prong portions 26b on the outer circumference of the bottom portion 22b and linking portions 27b that link these prong portions 26b, and by cutting off the linking portions 27b and the portion that includes the inner wall portion 24b from the formed workpiece, a pronged annular member that includes the circular bottom portion 22b that has a hole 23b and the prong portions 26b on the outer circumference of the bottom portion 22b.