RACE PRODUCTION METHOD - NTN TOYO BEARING CO LTD

Title:

RACE PRODUCTION METHOD

Document Type and Number:

WIPO Patent Application WO/2017/203914

Kind Code:

A1

Abstract:

This race production method comprises a step for obtaining a race by heating a steel (2) to a temperature equal to or higher than the A1 transition temperature at a forming table (3), and punching a portion of the steel (2) in a ring shape, and then hardening the ring-shaped steel (2) at the forming table. In the step for obtaining a race, the heating and punching are performed while tension is being applied to a first portion and a second portion of the steel (2) that are situated away from each other in at least one direction along the surface of the steel (2) with the forming table (3) being situated in the space delineated therebetween. Tension is applied so as to widen the section between the first and second portions of the steel (2) by a length that corresponds to an amount of thermal expansion taking place in the section between the first and second portions when the steel (2) is heated to the abovementioned temperature during the step for obtaining a race. The forming table (3) comprises a first die (30) for punching out the steel (2) and a second die (36) facing the first die (30), wherein a forming surface of the first die (30) or the second die (31, 32) has an indented curved surface (35A).

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Inventors:

MIZUTA KOHEI (JP)
OHKI CHIKARA (JP)
FUJIWARA HIROKI (JP)

Application Number:

PCT/JP2017/016168

Publication Date:

November 30, 2017

Filing Date:

April 24, 2017

Export Citation:

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Assignee:

NTN TOYO BEARING CO LTD (JP)

International Classes:

B21D28/00; B21D28/02; B21D37/16; B21D53/10; B21J1/06; B21J5/00; B21J5/08; C21D1/18; C21D9/00; C21D9/40; F16C33/62; F16C33/64

Domestic Patent References:

WO2016006550A1

2016-01-14

Foreign References:

JP2014231902A	2014-12-11
JPS5874623U	1983-05-20
US20130136387A1	2013-05-30

Other References: