Self-tapping method for machine screw and self-tapping pre-manufactured hole of machine screw

Abstract

The invention provides a self-tapping method of a machine screw. The method includes the step that a pre-manufactured hole is pre-formed before tapping of the machine screw, and is characterized in that a four-section structure is formed in the periphery of the hole inner wall of the pre-manufactured hole, thus, the quantity of tooth engagement can be guaranteed while tapping resistance of the machine screw is reduced, and tooth screw looseness is avoided.

Description

technical field [0001] The invention relates to the field of vehicle lamps, in particular to a self-tapping method of a mechanism screw and a self-tapping prefabricated hole. Background technique [0002] According to the classification of threads: screws can generally be divided into machine screws and self-tapping screws. Coarse teeth are generally used for machine-made screws, which need to be matched with corresponding standard internal threads, as shown in Figure 1. [0003] The threads of self-tapping screws are divided into coarse teeth and fine teeth, generally called type A and type AB (type A and type AB), most of which are AB teeth. Self-tapping screws do not need to cooperate with internal threads, only prefabricated holes are required, and matching threads are automatically generated when tapping, which is called thread for min. As shown in Figure 2. [0004] However, under some specific conditions, it is necessary to directly tap the original machine screw in...

AI Technical Summary

Problems solved by technology

[0004] However, under some specific conditions, it is necessary to directly tap the original machine screw into the prefabricated hole without thread. If the prefabricated hole is designed in the same way as the original self-tapping screw, it must not be tapped.

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