Method for manufacturing fastening screw and fastening screw

Abstract

Provided are a method for manufacturing a fastening screw and a fastening screw which are able to reduce the fastening time and to obtain a predetermined fastening force and to suppress the loosening of a screw. The method for manufacturing a fastening screw comprises: a preliminary upsetting step for forging a front end of a blank wire and forming a head having a depression in a condition, where a curve portion remains in an outer periphery to be formed into a bearing surface of the fastening screw, by means of a die having a protrusion protruding from a flat end face and a first punch having a cup-shaped cavity, the front end protruding from the protrusion of the die; a finish upsetting step for forging the head and forming a recess so that the depression of the head is not interfered with the recess by the die and a second punch having a protrusion for forming the recess on the head; and a thread forming step for processing a shank extending from the head and forming threads on the shank.

Description

technical field [0001] The present invention relates to a method of manufacturing a connecting screw and a connecting screw for connecting, for example, a component to a workpiece with a predetermined connecting force. Background technique [0002] In electronic products such as cellular phones, personal computers, and portable music players, or automotive parts that have become popular in recent years, due to their weight reduction, thinning, and miniaturization, etc., the use of fixing parts to thin workpieces formed structure. In such a component fixing structure, connecting screws are mainly used to fix the component. [0003] Among the connecting screws used in this fixing structure, there are the following examples: a cup-shaped flange integral with the head is formed with a plurality of protruding pieces, and the protruding pieces extend along the periphery of the cup-shaped flange and follow the Protruding from the joint surface in the loosening direction, the end ...

AI Technical Summary

Problems solved by technology

[0007] In the connecting screw of Cited Document 1, when tightening, a plurality of protruding pieces formed at equal intervals along the periphery of the joint surface may engage in the workpiece or deform the workpiece, so that a predetermined connecting force may not be obtained.

[0008] In addition, the connecting screw of Cited Document 2 has the following problem: Since a recess is formed on the joint surface of the head, even if the part can be fixed to the workpiece with an appropriate connecting force, the joint surface of the head of the screw will not be fixed on the part when it is seated on the part. In this state, it cannot be reliably connected to the parts on the outer periphery of the head, and the screws are prone to loosening. As time goes by, the screws loosen, and the fixed parts will be misaligned relative to the workpiece, etc.

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