Different material joining method

Patent metadata

Field	Value
Publication number	US-11400540-B2
Application number	US-201916572936-A
Country	US
Kind code	B2
Filing date	Sep 17, 2019
Priority date	Oct 31, 2018
Publication date	Aug 2, 2022
Grant date	Aug 2, 2022

Abstract

An iron rivet including a head and a shank, an aluminum plate, an iron plate, and first and second electrodes are prepared. A sandwiching step of sandwiching the rivet, the aluminum plate, and the iron plate between the first electrode and the second electrode, a penetration step of performing pressurization and current application by the first and second electrodes so that the shank penetrates through the aluminum plate, and a forming step of performing pressurization and current application by the first and second electrodes so that a nugget is formed between the shank and the iron plate are included. In the penetration step, the pressurization and current application is performed while air is blown to a side face of the shank so that the air hits a region around a boundary between the shank and the aluminum plate.

First claim

What is claimed is:

1. A different material joining method for joining a plurality of metal members by resistance welding by use of a rivet, the different material joining method comprising:
preparing a metal rivet including a head and a shank, first to nth metal members, and first and second electrodes, n being an integer of 2 or more, the first metal member being made of a material different from at least one of the second to nth metal members;
a sandwiching step of sandwiching, between the first electrode and the second electrode, the rivet and the first to nth metal members arranged in order of the head, the shank, and the first to nth metal members;
a penetration step of performing pressurization and current application on the rivet and the first to nth metal members by the first and second electrodes so that the shank penetrates through the first to (n−1)th metal members; and
a forming step of performing pressurization and current application on the rivet and the first to nth metal members by the first and second electrodes so that a nugget is formed between the shank and the nth metal member,
wherein, in the penetration step, the pressurization and current application is performed while air is blown to a side face of the shank so that the air hits a region around a boundary between the shank and the first metal member so as to blow off molten metal of the first metal member replaced with the shank spouting out from the boundary between the shank and the first metal member.

2. The different material joining method according to claim wherein, in the forming step, the pressurization and current application is performed while the air is blown to a side face of the head so that the air hits a region around a boundary between the head and the first metal member.

3. The different material joining method according to claim 1 , wherein:
the rivet is configured such that the head includes an annular wall projecting in a same direction as the shank so that an annular groove is formed around the shank, and a volume of the annular groove is smaller than a volume of a pilot portion of the shank, the pilot portion projecting from the annular wall; and
at least in the penetration step, an air flow rate is controlled so that molten metal is filled into the annular groove.

4. The different material joining method according to claim 3 , wherein a projection height of the annular wall is lower than a length of the shank.

5. The different material joining method according to claim 1 , wherein a first initial current value at a time when the pressurization and current application is started in the penetration step is not less than 0.8 times a second initial current value at a time when the pressurization and current application is started in the forming step.

6. The different material joining method according to claim 5 , wherein, in the forming step, downslope current application in which a current value is gradually decreased from the second initial current value is performed.

7. The different material joining method according to claim 5 , wherein the current value in the pressurization and current application in the penetration step is not less than the current value in the pressurization and current application in the forming step.

8. The different material joining method according to claim 1 , wherein, in the penetration step, the air is blown from two or more directions so as not to form a region that is not hit by the air around the boundary between the shank and the first metal member.

9. The different material joining method according to claim 8 , wherein, in the penetration step, first air is blown toward an axial center of the shank, and second air is blown toward the axial center of the shank from the direction having an angle of not less than 30 degrees but not more than 330 degrees from a blowing direction of the first air when the shank is viewed along an axial direction of the shank.

10. The different material joining method according to claim 8 , wherein, in the penetration step, first air is blown toward an axial center of the shank, and second air is blown toward the region that is not hit by the first air when the shank is viewed along an axial direction of the shank.

11. The different material joining method according to claim 1 , wherein, in the penetration step, the air is blown from a direction parallel to a plane perpendicular to the shank.

12. The different material joining method according to claim 1 , wherein, in the penetration step, the air is blown from a direction inclined from a plane perpendicular to the shank.

Assignees

• Toyota Motor Co Ltd

Inventors

• Kurokawa Shotaro
• Ogura Shuhei
• Kawakita Atsushi
• Shinohara Keisuke

Classifications

• B23K2103/02

  Iron or ferrous alloys · CPC title

• B23K2103/20

  Ferrous alloys and aluminium or alloys thereof · CPC title

• B23K2103/10

  Aluminium or alloys thereof · CPC title

• B23K11/115 Primary

  by means of two electrodes placed opposite one another on both sides of the welded parts · CPC title

• B23K11/20

  of different metals · CPC title