WELDING APPARATUS AND WELDING METHOD

• US 20150273619A1
• Filed: 03/31/2015
• Published: 10/01/2015
• Est. Priority Date: 03/31/2014
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: NAKAMURA, Masaya
• Granted Patent: US 10,449,620 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B23K 11/002 specially adapted for particular articles or work
• CPC Class Codes: B23K 11/0033 Welding locally a thin plate to a large piece
• CPC Class Codes: B23K 11/004 Welding of a small piece to a great or broad piece
• CPC Class Codes: B23K 11/0046 the extremity of a small piece being welded to a base, e.g. cooling studs or fins to tubes or plates
• CPC Class Codes: B23K 11/241 Electric supplies B23K11/248 takes precedence
• CPC Class Codes: B23K 11/252 using digital means
• CPC Class Codes: B23K 11/253 the measured parameter being a displacement or a position

Abstract

A welding apparatus for resistance-welding a tubular member and a bar member includes: a positioning jig configured to make contact with the bar member from one side of the bar member in a direction perpendicular to an extending direction of the bar member; a first power supply jig configured to press the bar member from the other side of the bar member in the direction; a second power supply jig provided on an anti-bar member side of the tubular member and configured to apply pressure to contact surfaces of the bar member and the tubular member; and means for supplying, with the bar member pressed between the positioning jig and the first power supply jig and the second power supply jig applying pressure to the contact surfaces, electric current to the first power supply jig, the bar member, the contact surfaces, the tubular member and the second power supply jig.

Claims

1. A welding apparatus for resistance-welding a tubular member and a bar member arranged in contact with one axial end surface of the tubular member, the apparatus comprising:

a positioning jig configured to make contact with the bar member from one side of the bar member in a direction perpendicular to an extending direction of the bar member;

a first power supply jig configured to press the bar member from the other side of the bar member in the direction perpendicular to the extending direction of the bar member;

a second power supply jig provided on an anti-bar member side of the tubular member and configured to apply pressure to contact surfaces of the bar member and the tubular member; and

means for supplying, with the bar member pressed between the positioning jig and the first power supply jig and the second power supply jig applying pressure to the contact surfaces of the bar member and the tubular member, electric current to the first power supply jig, the bar member, the contact surfaces, the tubular member and the second power supply jig.

2. The welding apparatus as set forth in claim 1, further comprising a pressure application jig that is provided on an anti-housing side of the bar member to apply, together with the second power supply jig, pressure to the contact surfaces of the bar member and the tubular member.

3. The welding apparatus as set forth in claim 1, wherein the first power supply jig has a contacting portion capable of making surface contact or line contact with the bar member.

4. The welding apparatus as set forth in claim 1, wherein the first power supply jig is configured to press the bar member at a position slightly away from the contact surfaces of the bar member and the tubular member so as to suppress buckling of the bar member due to Joule heat on a housing side of a contact region between the first power supply jig and the bar member.

5. The welding apparatus as set forth in claim 1, wherein the bar member has a smaller heat capacity than the tubular member, and

the welding apparatus further comprises means for controlling the electric current supplied by the electric current supplying means so as to keep the temperature of the bar member at a temperature at which it is possible to suppress melting of the bar member until a predetermined time has elapsed from start of the electric current supply and then increase the temperatures of the bar member and the tubular member to temperatures at which it is possible to melt the bar member and the tubular member.

6. The welding apparatus as set forth in claim 5, further comprising means for detecting a temperature of the contact surfaces,

wherein

the controlling means controls the electric current supplied by the electric current supplying means based on the temperature of the contact surfaces detected by the temperature detecting means.

7. The welding apparatus as set forth in claim 6, wherein the controlling means controls the electric current supplied by the electric current supplying means so as to keep the temperature of the bar member at the temperature at which it is possible to suppress melting of the bar member until the temperature of the contact surfaces detected by the temperature detecting means has been increased to a temperature at which it is possible to melt the tubular member.

8. The welding apparatus as set forth in claim 5, father comprising means for detecting a displacement magnitude caused by a welding deformation of the tubular member and the bar member,

wherein

the controlling means controls, based on the displacement magnitude detected by the displacement magnitude detecting means, a pressure-applying force of the second power supply jig as well as the electric current supplied by the electric current supplying means.

9. The welding apparatus as set forth in claim 1, wherein the electric current supplying means supplies, as the electric current, DC electric current through an inverter control.

10. A method of resistance-welding a tubular member and a bar member arranged in contact with one axial end surface of the tubular member, the method comprising the steps of:

pressing the bar member by a first power supply jig;

applying pressure to contact surfaces of the bar member and the tubular member by a second power supply jig; and

supplying electric current, after the pressing step and the pressure applying step, electric current to the first power supply jig, the bar member, the contact surfaces, the tubular member and the second power supply jig.

11. The method as set forth in claim 10, wherein the bar member has a smaller heat capacity than the tubular member, and

in the electric current supplying step, the electric current is supplied so as to keep the temperature of the bar member at a temperature at which it is possible to suppress melting of the bar member until a predetermined time has elapsed from start of the electric current supply and then increase the temperatures of the bar member and the tubular member to temperatures at which it is possible to melt the bar member and the tubular member.

12. The method as set forth in claim 10, further comprising, before the pressing step and the pressure applying step, a step of forming a protrusion at a tubular member-side end of the bar member.

13. The method as set forth in claim 10, further comprising, before the pressing step and the pressure applying step, a step of forming a recess, which is smaller than a cross section of the bar member, in the axial end surface of the tubular member facing the bar member.

14. The method as set forth in claim 10, further comprising, before the pressing step and the pressure applying step, a step of forming a protrusion on the axial end surface of the tubular member facing the bar member.