Patent ID: 7595961

Claim:
A base member having a relatively large thickness to which an attachment member is attached, the attachment member being composed of a relatively thin sheet member which has a cylindrical boss section projecting from a surface of the sheet member and which has a path passing through the sheet member and reaching the extreme end of the boss section, the base member comprising: a through hole which passes therethrough in the thickness direction thereof and into which the boss section is inserted, wherein the attachment member is caulked to the base member by plastically deforming the boss section by causing a spherical body whose diameter is larger than that of the path to pass through the path in the state that the boss section is inserted into the through hole; the through hole has an escape section into which a part of the boss section, which is plastically deformed when the attachment member is caulked to the base member, escapes in the radial direction of the path; and the through hole and the escape section form an opening whose circumference is closed, and the opening is longer in a longitudinal direction of the base.