Shaft diameter enlargement condition setting method, shaft diameter enlargement method and shaft diameter enlargement apparatus

Patent metadata

Field	Value
Publication number	US-11565307-B2
Application number	US-201816753069-A
Country	US
Kind code	B2
Filing date	Oct 31, 2018
Priority date	Nov 1, 2017
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

A method for setting conditions for a shaft diameter enlargement, a shaft diameter enlargement method, and a shaft diameter enlargement apparatus are provided. A controller of the shaft diameter enlargement apparatus controls a compressing section, a bending section, and a rotating section to enlarge an intermediate portion of a shaft workpiece to have a predetermined outer diameter by rotating the shaft workpiece about its axis with axial compressive force a bending angle being applied to the intermediate portion. The controller determines whether the shaft workpiece is acceptable, based on the number of rotations of die shaft workpiece required for enlarging the intermediate portion to have the predetermined outer diameter or based on an enlargement ratio of the intermediate portion.

First claim

The invention claimed is:

1. A method for setting conditions for a shaft diameter enlargement in which an axially intermediate portion of a shaft workpiece is enlarged in a radial direction by rotating the shaft workpiece about an axis of the shaft workpiece with axial compressive force being applied to the intermediate portion and with a bending angle being applied to the intermediate portion, the method comprising:
setting an allowable number of rotations based on test data, wherein the test data is obtained by performing the shaft diameter enlargement on test shafts, each of the test shafts being made of a same material and having a same shape as the shaft workpiece, wherein the test data is indicative of a relationship between, for each of the test shafts, a number of rotations of the test shaft required for enlarging an axially intermediate portion of the test shaft to a predetermined outer diameter and a crack occurrence probability at a boundary between the intermediate portion of the test shaft and a shaft portion of the test shaft other than the intermediate portion, and wherein the allowable number of rotations is set such that the crack occurrence probability at the boundary is equal to or lower than a threshold value; and
setting a number of rotations to be performed during the shaft diameter enlargement to enlarge the intermediate portion of the shaft workpiece to the predetermined outer diameter, the set number of rotations being equal to or less than the allowable number of rotations.

2. The method according to claim 1 , wherein the test data is obtained by performing the shaft diameter enlargement on the test shafts with a same bending angle as in the shaft diameter enlargement to be performed on the shaft workpiece.

3. A method for setting conditions for a shaft diameter enlargement in which an axially intermediate portion a shaft workpiece is enlarged in a radial direction by rotating the shaft workpiece about an axis of the shaft workpiece with axial compressive force being applied to the intermediate portion and with a bending angle being applied to the intermediate portion, the method comprising:
setting a maximum allowable enlargement ratio based on test data, wherein the test data is obtained by performing the shaft diameter enlargement on test shafts, each of the test shafts having a same material and a same shape as the shaft workpiece, wherein the test data is indicative of a relationship between, for each of the test shafts, an enlargement ratio and a crack occurrence probability at an outer periphery of an axially intermediate portion of the test shaft, the enlargement ratio being a ratio of an outer diameter of the intermediate portion of the test shaft after the shaft diameter enlargement to an outer diameter of the test shaft before the shaft diameter enlargement, and wherein the maximum allowable enlargement ratio is set such that the crack occurrence probability at the outer periphery is equal to or lower than a threshold value; and
setting an enlargement ratio to be obtained by the shaft diameter enlargement to enlarge the intermediate portion of the shaft workpiece to have a predetermined outer diameter, the set enlargement ratio being equal to or smaller than the maximum allowable enlargement ratio.

4. A shaft diameter enlargement method for enlarging an axially intermediate portion a shaft workpiece in a radial direction, the shaft diameter enlargement method comprising:
rotating the shaft workpiece about an axis of the shaft workpiece with axial compressive force being applied to the intermediate portion and with a bending angle being applied to the intermediate portion;
determining whether the shaft workpiece is acceptable with regard to cracking probability based on a number of rotations of the shaft workpiece required for enlarging the intermediate portion of the shaft workpiece to have a predetermined outer diameter; and
setting an allowable number of rotations based on test data, wherein the test data is obtained by performing a shaft diameter enlargement on test shafts, each of the test shafts being made of a same material and having a same shape as the shaft workpiece, wherein the test data is indicative of a relationship between, for each of the test shafts, a number of rotations of the test shaft required for enlarging an axially intermediate portion of the test shaft to a predetermined outer diameter and a boundary crack occurrence probability at a boundary between the intermediate portion of the test shaft and a shaft portion of the test shaft other than the intermediate portion, and wherein the allowable number of rotations is set such that the boundary crack occurrence probability at the boundary is equal to or lower than a threshold value,
wherein the shaft workpiece is determined as being acceptable when the number of rotations of the shaft workpiece is equal to or less than the allowable number of rotations, and the shaft workpiece is determined as being unacceptable when the number of rotations of the shaft workpiece exceeds the allowable number of rotations.

5. The shaft diameter enlargement method according to claim 4 , wherein the test data is obtained by performing the shaft diameter enlargement on the test shafts with a same bending angle as in the shaft diameter enlargement to be performed on the shaft workpiece.

6. The shaft diameter enlargement method according to claim 4 , further comprising:
setting a maximum allowable enlargement ratio based on the test data, wherein the test data is also indicative of a relationship between, for each of the test shafts, an enlargement ratio and an outer periphery crack occurrence probability at an outer periphery of the axially intermediate portion of the test shaft, the enlargement ratio being a ratio of an outer diameter of the intermediate portion of the test shaft after the shaft diameter enlargement to an outer diameter of the test shaft before the shaft diameter enlargement, and wherein the maximum allowable enlargement ratio is set such that the outer periphery crack occurrence probability at the outer periphery is equal to or lower than another threshold value; and
setting an enlargement ratio to be obtained by the shaft diameter enlargement to enlarge the intermediate portion of the shaft workpiece to have the predetermined outer diameter, the set enlargement ratio being equal to or smaller than the maximum allowable enlargement ratio.

7. A shaft diameter enlargement method for enlarging an axially intermediate portion a shaft workpiece in a radial direction, the shaft diameter enlargement method comprising:
rotating the shaft workpiece about an axis of the shaft workpiece with an axial compressive force being applied to the intermediate portion and with a bending angle being applied to the intermediate portion;
determining whether the shaft workpiece is acceptable with regard to cracking probability based on a shaft workpiece enlargement ratio, the shaft workpiece enlargement ratio being a ratio of an outer diameter of the intermediate portion of the shaft workpiece after being enlarged to an outer diameter of the intermediate portion before being enlarged; and
setting a maximum allowable enlargement ratio based on test data, wherein the test data is obtained by performing a shaft diameter enlargement on test shafts, each of the test shafts having a same material and a same shape as the shaft workpiece, wherein the test data is indicative of a relationship between, for each of the test shafts, a test shaft enlargement ratio and an outer periphery crack occurrence probability at an outer periphery of an axially intermediate portion of the test shaft, the test shaft enlargement ratio being a ratio of an outer diameter of the intermediate portion of the test shaft after the shaft

Assignees

• Neturen Co Ltd

Inventors

• Okamoto Mitsuhiro
• Ikuta Fumiaki
• Kuwahara Yoshitaka
• Mori Kazuki
• Ikeda Takashi

Classifications

• B21K1/12 Primary

  of specially-shaped cross-section · CPC title

• B21J5/08 Primary

  Upsetting · CPC title

• B21K23/04

  flanged articles (B21K1/28 takes precedence; flanging tubes B21D) · CPC title