Self-tapping screw quickly installed on plastic part and machining device thereof

Abstract

The invention relates to a self-tapping screw quickly installed on a plastic part. The self-tapping screw comprises a head part and a screw rod part, wherein the screw rod part comprises a parallel thread part and a guide thread part; the parallel thread part forms thread teeth with the consistent tooth height from the head part to the guide thread part; the guide thread part forms thread teeth with the tooth height gradually decreased from the parallel thread part to the tail end of the screw rod part; each thread tooth comprises a tooth tip and a tooth bottom; the thread pitch of the threadteeth is 2.69mm; the length of the guide thread part is 2-2.5 thread pitches; and the included angle between the tangent line of the tooth tip of the guide thread part and the tangent line of the tooth tip of the parallel thread part is 8-10 degrees. By the adoption of the technical scheme, the thread parts are used for connecting a steel part and the plastic part after being subjected to quenching and tempering heat treatment, the plastic part does not need to be provided with a machined thread by itself through the self-extrusion screw, only one unthreaded hole is needed, an embedded nut isomitted, the connecting and locking strength can meet the requirement for high strength, the self-tapping screw is perfectly matched with plastic in the locking process, and the situation that the plastic is damaged by heat energy generated by locking is reduced.

Description

technical field [0001] The invention belongs to the technical field of machinery, and in particular relates to a self-tapping screw quickly installed on a plastic part and a processing device thereof. Background technique [0002] With the promotion of energy saving and emission reduction, the lightweight of automobiles continues to expand, and the number of parts used in metal sheets and plastic parts is increasing, especially the connecting mechanism of the air filter assembly in the engine compartment. The connection parts are all self-tapping screws, and a screw with good installation guidance, high efficiency, and good connection effect that can be directly connected to the plastic parts is needed. [0003] Ordinary self-tapping screws have small thread pitch, poor self-cutting performance, and large thread cutting surface, which will generate large radial force. When connecting and assembling, the self-tapping screw is screwed into the unthreaded bottom hole of the con...

AI Technical Summary

Problems solved by technology

[0005] Tooling molds for the production of automotive fasteners. Tooth plate molds are the most commonly used thread tools for processing screws in the fastener industry. Commonly used tooth plate molds generally have only one tooth pattern. The screws produced by this commonly used tooth plate mold are easy to break or cannot enter at all when encountering the metal plate, which will affect the safety of the assembly work, and will also cause slippage during the production process, and the production cycle will not be fast. Smoothness leads to problems such as low work efficiency and low production pass rate, so we need a tooth plate mold that can efficiently produce screws that easily enter the metal plate and are firmly connected

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