Burring method and burring apparatus

Patent metadata

Field	Value
Publication number	US-2016339501-A1
Application number	US-201515110989-A
Country	US
Kind code	A1
Filing date	Jan 29, 2015
Priority date	Jan 29, 2014
Publication date	Nov 24, 2016
Grant date	—

Abstract

In the present invention, in a piercing punch and a burring punch which are shaft members having a first axis line as the center axis lines and are provided so as to be movable along the first axis line, first, after prepared holes having the first axis line as the center axis lines with respect to the first wall portion and the second wall portion are formed using the piercing punch, burring holes having the first axis line as the center axis lines with respect to the first wall portion and the second wall portion are formed using the burring punch.

First claim

What is claimed is:

1 . A burring method for forming burring holes having a first axis line as center axis lines with respect to a first wall portion and a second wall portion facing each other, the burring method comprising:
a first process of disposing an internal unit of a burring apparatus between the first wall portion and the second wall portion, disposing a first external unit of the burring apparatus outside the first wall portion, and disposing a second external unit of the burring apparatus outside the second wall portion; a second process of, out of a piercing punch and a burring punch which are shaft members having the first axis line as the center axis lines provided in at least one of the internal unit, the first external unit, and the second external unit, and are provided so as to be movable along the first axis line, first, forming prepared holes having the first axis lines as the center axis lines with respect to the first wall portion and the second wall portion using the piercing punch, and thereafter, forming burring holes having the first axis line as the center axis lines with respect to the first wall portion and the second wall portion using the burring punch; and a third process of detaching the internal unit, the first external unit, and the second external unit from the first wall portion and the second wall portion.

2 . The burring method according to claim 1 ,
wherein in the second process, after one of the prepared holes is formed on the first wall portion using a first piercing punch provided in the first external unit, one of the burring holes is formed by bending a peripheral edge portion of the prepared hole of the first wall portion to the inside of the first wall portion using a first burring punch which is provided in the first external unit and has the first axis line as the center axis line along with the first piercing punch; and after the other prepared hole is formed on the second wall portion using a second piercing punch provided in the second external unit, the other burring hole is formed by bending a peripheral edge portion of the prepared hole of the second wall portion to the inside of the second wall portion using a second burring punch which is provided in the second external unit and has the first axis line as the center axis line along with the second piercing punch.

3 . The burring method according to claim 2 ,
wherein in the first process, among a first burring holder which is provided in the first external unit and has a first through hole serving as a passage of the first burring punch, the first burring punch which is disposed inside the first through hole, and the first piercing punch which is disposed inside the first burring punch, the first burring holder and the first burring punch come into pressure contact with an outer wall surface of the first wall portion in a state where center axis lines of the first through hole, the first piercing punch, and the first burring punch coincide with the first axis line; among a second burring holder which is provided in the second external unit and has a second through hole serving as a passage of the second burring punch, the second burring punch which is disposed inside the second through hole, and the second piercing punch which is disposed inside the second burring punch, the second burring holder and the second burring punch come into pressure contact with an outer wall surface of the second wall portion in a state where center axis lines of the second through hole, the second piercing punch, and the second burring punch coincide with the first axis line; a first burring die which is provided in the internal unit and has a first forming hole, and a first piercing die which is provided inside the first forming hole and has a first piercing hole come into pressure contact with an inner wall surface of the first wall portion in a state where center axis lines of the first forming hole and the first piercing hole coincide with the first axis line; and a second burring die which is provided in the internal unit and has a second forming hole, and a second piercing die which is provided inside the second forming hole and has a second piercing hole come into pressure contact with an inner wall surface of the second wall portion in a state where center axis lines of the second forming hole and the second piercing hole coincide with the first axis line, and wherein in the second process, one of the prepared holes is formed on the first wall portion by moving the first piercing punch from the outside of the first wall portion to the inside thereof along the first axis line such that the first piercing punch is inserted into the first piercing hole; the other prepared hole is formed on the second wall portion by moving the second piercing punch from the outside of the second wall portion to the inside thereof along the first axis line such that the second piercing punch is inserted into the second piercing hole; the peripheral edge portion of the prepared hole of the first wall portion is bent to the inside of the first wall portion to form one of the burring holes by moving the first burring punch from the outside of the first wall portion to the inside thereof along the first axis line such that the first burring punch is inserted into the first forming hole, and the first piercing die is returned to a position close to a center between the first wall portion and the second wall portion; the peripheral edge portion of the prepared hole of the second wall portion is bent to the inside of the second wall portion to form the other burring hole by moving the second burring punch from the outside of the second wall portion to the inside thereof along the first axis line such that the second burring punch is inserted into the second forming hole, and the second piercing die is returned to a position close to the center between the first wall portion and the second wall portion; and the first burring die and the second burring die are returned to the position close to the center between the first wall portion and the second wall portion after both of the burring holes are formed.

4 . The burring method according to claim 3 ,
wherein in the first process, the first burring die comes into pressure contact with the inner wall surface of the first wall portion and the second burring die comes into pressure contact with the inner wall surface of the second wall portion by inserting a first stopper into a portion between the first burring die and the second burring die in the internal unit; and the first piercing die comes into pressure contact with the inner wall surface of the first wall portion and the second piercing die comes into pressure contact with the inner wall surface of the second wall portion by inserting a second stopper into a portion between the first piercing die and the second piercing die, and wherein in the second process, after the second stopper is removed from the portion between the first piercing die and the second piercing die, one of the burring holes is formed on the first wall portion by inserting the first burring punch into the first forming hole, and the other burring hole is formed on the second wall portion by inserting the second burring punch into the second forming hole; and after both of the burring holes are formed, the first stopper is removed from the portion between the first burring die and the second burring die, and the first burring die and the second burring die are returned to the position close to the center between the first wall portion and the second wall portion by applying an external force to the first burring die and the second burring die in a direction approaching each other.

5 . The burring method according to claim 1 ,
wherein in the second process,

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Shirakami Satoshi
• Mizumura Masaaki
• Yoshida Tohru

Classifications

• B21D41/025

  by means of impact-type swaging hand tools · CPC title

• B21D28/28

  in tubes or other hollow bodies · CPC title

• B21D28/16 Primary

  Shoulder or burr prevention {, e.g. fine-blanking} · CPC title

• B21D28/14

  Dies (ejecting or stripping-off devices arranged in punching machines or tools B21D45/00) · CPC title