Outer diameter and tooth profile progressive extruding screw tap for trapezoidal inner threads

Abstract

The invention discloses an outer diameter and tooth profile progressive extruding screw tap for trapezoidal inner threads. The outer diameter and tooth profile progressive extruding screw tap comprises a screw tap clamping end (1), a screw tap rod body (2) and a screw cap extruding body (3). The outer diameter and tooth profile progressive extruding screw tap is characterized in that the screw tap extruding body (3) comprises a guide part a, an extruding part b and a correcting part c; a ring of extruding edge valleys is formed between adjacent two rings of extruding teeth of the screw tap extruding body (3); each ring of extruding teeth is equipped with six extruding edges; each extruding edge and the positive section, in the length direction of the extruding screw tap, of the corresponding extruding edge are trapezoidal; a cooling liquid channel is formed between every two adjacent extruding edges; acting surfaces of the extruding edges and workpieces generate acting force perpendicular to the axial direction; the extruding screw tap continuously guides to perform thread processing; when the workpieces are slowly extruded with teeth, and are in contact with positions of the extruding edge valleys along with continuous growth of the teeth, the six extruding edge valleys perform flattening correcting on trapezoidal tooth tops grown out from the workpieces, so that inner threads with inner thread surface roughness Ra of 0.8-1.6 are obtained. The outer diameter and tooth profile progressive extruding screw tap can realize cold-extrusion processing of trapezoidal inner threads, and can improve surface quality and fatigue resistance of the processed threads.

Description

technical field [0001] The invention relates to a mechanical processing tool, in particular to a trapezoidal internal thread cold extrusion processing tool, in particular to a trapezoidal internal thread progressive extrusion tap with outer diameter and tooth shape. Background technique [0002] There are many methods of internal thread processing in modern machinery manufacturing. In addition to cutting processing, internal thread cold extrusion technology is a new processing method newly developed in recent years, that is, at room temperature, using extrusion taps on prefabricated workpieces The process of forming the internal thread through the action of the tap teeth on the bottom hole to make the metal flow plastically. However, in the process of processing, it is necessary to achieve the plastic deformation of the workpiece, which often requires a large extrusion force; while the angle of the trapezoidal tooth profile is only 30°, which is half of the 60° angle of the ...

AI Technical Summary

Problems solved by technology

[0004] The object of the present invention is to design a trapezoidal internal thread with outer diameter and tooth shape progressive extrusion tap for the existing trapezoidal internal thread cold extrusion taps that cannot process high-life and high-reliability trapezoidal internal threads. Combined with a low-frequency torsional vibration device, it can process high-quality trapezoidal internal threads, and can be widely used in the extrusion processing of trapezoidal internal threads for difficult-to-machine materials such as stainless steel and titanium alloys

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