Fastening member, bonded joint, and method for manufacturing bonded joint

A bonded joint comprising:

• a bonding target object;
• and a fastening member bonded to the bonding target object,
• wherein the bonding target object has a first plate portion and a second plate portion facing the first plate portion,
• the first plate portion has a first hole,
• the second plate portion has a second hole,
• the fastening member is a fastening member having a screw hole extending in an axial direction and includes
• a body portion extending in the axial direction,
• a first end portion located at one side of the body portion in the axial direction,
• a second end portion located at another side of the body portion in the axial direction,
• a first linking portion that links the body portion and the first end portion, and
• a second linking portion that links the body portion and the second end portion,
• the screw hole is provided in at least one of the body portion or the second end portion,
• the first end portion is disposed at the one side in the axial direction with respect to the first plate portion,
• the second end portion is disposed at the other side in the axial direction with respect to the second plate portion,
• the first linking portion is disposed inside the first hole,
• the second linking portion is disposed inside the second hole,
• the body portion is disposed between the first plate portion and the second plate portion, and
• in the axial direction,
• an outer diameter of the first linking portion is smaller than an outer diameter of a part of the body portion that is adjacent to the first linking portion,
• a thickness of the first linking portion is smaller than a thickness of the part of the body portion that is adjacent to the first linking portion,
• an outer diameter of the first end portion is larger than a diameter of the first hole,
• a circumferential edge part of the first hole in the first plate portion is sandwiched between the body portion and the first end portion from both sides in the axial direction, and
• an outer diameter of the second end portion is larger than a diameter of the second hole, and a circumferential edge part of the second hole is supported by the second end portion.

A method for manufacturing a bonded joint in which a bonding target object and a fastening member are bonded to each other,

• wherein the bonding target object has a first plate portion and a second plate portion facing the first plate portion,
• the first plate portion has a first hole, and the second plate portion has a second hole,
• the fastening member includes
• a screw hole extending in an axial direction,
• a body portion extending in the axial direction,
• a first end portion located at one side of the body portion in the axial direction,
• a second end portion located at another side of the body portion in the axial direction,
• a first linking portion that links the body portion and the first end portion, and
• a second linking portion that links the body portion and the second end portion,
• the screw hole is provided in at least one of the body portion or the second end portion,
• a part of the body portion that is adjacent to the first linking portion and the first linking portion have outer diameters with different values,
• outer diameters of a part of the first end portion that is adjacent to the first linking portion and the first linking portion are smaller than the outer diameter of the part of the body portion that is adjacent to the first linking portion,
• a part of the body portion that is adjacent to the second linking portion and the second end portion have outer diameters with different values, and
• thicknesses of the first end portion and the first linking portion, as viewed in the axial direction, are smaller than a thickness of the body portion,
• the method comprising:
• a step of preparing the bonding target object and the fastening member;
• a first step;
• and a second step,
• wherein, in the first step:
• the first end portion is disposed at the one side in the axial direction with respect to the first plate portion,
• the second end portion is disposed at the other side in the axial direction with respect to the second plate portion,
• the first linking portion is disposed inside the first hole,
• the second linking portion is disposed inside the second hole,
• the body portion is disposed between the first plate portion and the second plate portion,
• the part of the body portion that is adjacent to the first linking portion is brought into contact with a circumferential edge part of the first hole in the first plate portion from the other side in the axial direction, and
• a caulking preparation state is set in which a part of the second end portion that is adjacent to the second linking portion is brought into contact with a circumferential edge part of the second hole in the second plate portion from the other side in the axial direction, or the part of the body portion that is adjacent to the second linking portion is brought into contact with the circumferential edge part of the second hole in the second plate portion from the one side in the axial direction;
• and
• wherein, in the second step, the first end portion is deformed by energizing, heating, and pressurizing the fastening member from both sides in the axial direction in the caulking preparation state to form a deformed portion, and the circumferential edge part of the first hole in the first plate portion is sandwiched between the body portion and the deformed portion from both sides in the axial direction.