Staking bolt

Abstract

This staking bolt comprises a head section 10 and a shaft section 11 on which an external thread 12 is formed. A ring-shaped protrusion 20 and a ring groove 21, which is located on the head-section side of the ring-shaped protrusion 20, are formed on the upper end of the shaft section 11. The head section 10 is flat, and a rotation-prevention protrusion 14, which is provided with a plurality of radial arm sections 15, protrudes at a thickness of t on the seating surface 13 of the head section. The minimum diameter D between the arm sections 15 is greater than the outer diameter d of the ring-shaped protrusion 20, and t*(D-d) / 2, which is the vertical cross-sectional area A of the minimum diameter section of the rotation-prevention protrusion 14, is greater than or equal to the vertical cross-sectional area of the ring groove 21.

Description

technical field [0001] The present invention relates to a self-locking bolt which is pressed and fixed to the surface of a metal plate as a target member for fastening other members. Background technique [0002] The self-locking bolt is a bolt that is press-fitted into a bottom hole of a metal plate as a target member with a tool, and plastically flows a metal material in an annular groove formed around a shaft, thereby being pressed and fixed to the metal plate. A larger pull-out load (pull-out load in the axial direction) is required for the self-locking bolt. In addition, compared with the self-locking bolt after being pressed and fixed, other parts are fastened and connected by nuts afterwards, so a larger idling torque (the torque at which the self-locking bolt starts idling relative to the metal plate) is desired, as shown in the patent As shown in Document 1, a self-locking bolt in which a rotation-preventing protrusion is formed on the contact surface of the head i...

AI Technical Summary

Problems solved by technology

However, with such an existing structure, it is not easy to completely fill the interior of the annular groove 4 with metal material in the pressing process, and the idling torque after pressing is reduced to below 10 Nm.

In addition, the conventional self-locking bolt shown in Patent Document 1 has a large head 1, so it can only be pressed and fixed to a thick metal plate 5.

In addition, the conventional self-locking bolt shown in Patent Document 1 cannot screw the nut close to the head 1 because the head 1 is separated from the start position of the external thread 6 of the shaft. If the total thickness of the parts to be fastened is not thick enough, it cannot be fixed with nuts

Images