Bonding device and bonding method for friction stir bonding and resistance welding

1 . A bonding device for joining together a first member, an intermediate member, and a second member which are electroconductive, extend along a prescribed major plane, and are layered in this order as a laminated assembly, comprising:

an anvil configured to support a first surface of the laminated assembly provided by the first member, and including an electroconductive part abutting against the first surface;

a probe configured to rotate around a central axial line crossing the major plane and move toward and away from a second surface of the laminated assembly provided by the second member at a position corresponding to the anvil, the probe being at least partly electroconductive and having a tip end;

a drive mechanism configured to rotate the probe around the central axial line and move the probe toward and away from the second member along the central axial line;

an electric power supply electrically connected to the anvil and the probe to conduct electric current through the laminated assembly via the anvil and the probe; and

a control unit for controlling operation of the drive mechanism and the electric power supply, the control unit configured to:

control the drive mechanism to push the probe into the laminated assembly from the second surface while rotating the probe around the central axial line;

monitor a position of the tip end of the probe along the central axial line;

control the electric power supply to initiate conduction of electric current between the probe and the anvil once the tip end of the probe reaches the intermediate member; and then

control the drive mechanism to pull the probe away from the laminated assembly,

thereby the first member and the intermediate member are joined to each other by resistance welding and the second member and the intermediate member are joined to each other by friction stir bonding.

2 . The bonding device according to claim 1 , further comprising a shoulder member having a shoulder contact surface configured to be pressed against the second surface, a thorough hole configured to receive the probe, and a recess recessed relative to the shoulder contact surface so as to define a bottom surface opposing the second surface and partly receive the probe, wherein the recess is configured to receive a portion of the second member that is pushed away by the probe and left on the laminated assembly when the probe is plunged into the laminated assembly.

3 . The bonding device according to claim 2 , wherein the shoulder member is at least partly electroconductive, and the probe is provided with a probe conductive part extending from a part electrically connected to the power supply to the tip end of the probe opposing the second surface, and a probe insulating part provided on an outer periphery of the probe so as to electrically insulate the probe conductive part from an inner circumferential surface of the through hole.

4 . The bonding device according to claim 2 , wherein the shoulder member is partly electroconductive, and is provided with a shoulder member insulating part extending over the shoulder contact surface and an inner peripheral surface of the through hole so as to prevent electric current from flowing from the probe to the shoulder member.

5 . The bonding device according to claim 2 , wherein the friction stir welding is a friction stir spot welding, and the shoulder contact surface has an annular shape centered around the probe.

6 . The bonding device according to claim 2 , wherein the friction stir welding is a friction stir line welding, and the recess is open in a rear side thereof with respect to a traveling direction of the shoulder member relative to the laminated assembly at time of the friction stir line welding.