Upsetting method and upsetting apparatus

Abstract

To provide an upsetting method capable of efficiently expanding a bar-shaped raw material at least two portions. A plurality of guides 31 and 32 each having an insertion hole 34 are prepared. The bar-shaped raw material 1 secured to a fixed die 20 is inserted and held in each insertion hole 34 of the plurality of guides 31 and 32 in order. Then, a first exposed portion 4 of the raw material 1 exposed between a first guide 31 located at the foremost side of the plurality of guides 31 and 32 and the fixed die 32 is expanded in diameter by moving the plurality of guides 31 and 32 in a direction opposite to a moving direction of the punch 50R in a mutually adhering manner while pressurizing the raw material 1 in the axial direction with the punch 50R. After completion of the movement of the first guide 31, a second exposed portion of the raw material 1 exposed between both the guides 31 and 32 is expanded in diameter by relatively moving the second guide 32 located behind the first guide 31 among the plurality of guides 31 and 32 in a direction opposite to a moving direction of the punch 50R.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]The present application is a division of application Ser. No. 11 / 342,650, filed on Jan. 31, 2006, which claims priority to Japanese Patent Application No. 2005-24178 filed on Jan. 31, 2005, and U.S. Provisional Application No. 60 / 649,547 filed on Feb. 4, 2005, the entire disclosures of which are incorporated herein by reference in their entireties.FIELD OF THE INVENTION[0002]The present invention relates to an upsetting method and an upsetting apparatus for radially expanding two or more portions of a bar-shaped raw material.DESCRIPTION OF THE RELATED ART[0003]In general, upsetting is executed to expand a diameter of a certain portion of a material by pressurizing a bar-shaped raw material in an axial direction thereof. In this upsetting, if a material buckles at the time of the working, the obtained product (upsetting manufactured product) becomes poor in shape (e.g., wrinkles, scratches, etc.), which causes degradation in value as a pro...

AI Technical Summary

Benefits of technology

Enables efficient diameter expansion of multiple portions with reduced molding pressure and cost, preventing buckling and allowing for the production of high-quality upsetting manufactured products.

Problems solved by technology

In this upsetting, if a material buckles at the time of the working, the obtained product (upsetting manufactured product) becomes poor in shape (e.g., wrinkles, scratches, etc.), which causes degradation in value as a product.

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