| 摘要 |
<p>A metallic nut body (1), comprising a cylindrical body (3) having female threads (5), a seat part (7) which is projected radially from the lower end of the cylindrical body (3) and has a lower surface in contact with a member to be fixed (30), and ribs (13) which are provided to extend from the upper surface of the seat part (7) continuously to the side surface of the cylindrical body (3) and to be engageable with a tightening tool, wherein a recessed part (9) is provided in the portion of lower surface of the seat part (7) extending from the peripheral part to the axis so that it is deformed by a pressing force given from the contact points of the member to be fixed (30) when male threads (23) are screwed into the female threads (5), and the ribs (13) are provided so that a pressing force acting from the member to be fixed (30) onto the seat part (7) is transmitted to the cylindrical body (3), whereby, when the nut is tightened with a specified tightening force or more, the seat part (7) is deformed by a pressing force from the member to be fixed (30) and a positive locking effects can be obtained.</p> |
