SU1637924A1 - Forming tap - Google Patents

Abstract

The invention relates to the processing of metals by pressure, in particular to an instrument for the manufacture of internal threads. The purpose of the invention is to increase the durability of the tap by improving the deformation conditions during thread formation. The tap contains intake and calibration parts, a transition zone and a shank. On the intake part of the tap, a thread is made with a rounded shape of the vertices, on the calibrating part - with flat-cut tops, and in the transitional zone - with the peaks gradually moving from the rounded to the flat-cut. The presence of rounded-shaped vertices on the most loaded turns of the intake part and the transition zone of the tap facilitate the conditions of plastic deformation. The coils of the calibrating part with flat-cut tops are intended for the final formation of the thread profile. Improving plastic deformation conditions provides an increase in the life of the tap. 1 з п ф-лы, 2 or ё

Description

The invention relates to the processing of metals by pressure and can be used in the manufacture of internal threads by plastic deformation.

The aim of the invention is to increase the durability of the tap by improving the conditions of deformation.

Figure 1 shows the thread profile of the tap; FIG. 2 shows the node I in FIG. one.

The tap consists of the intake part 1, the calibrating part 2, the transition zone 3 and the shank 4. On the intake part of the tap, a thread is made with the tops of the rounded profile. Such a geometry of the vertices greatly facilitates the conditions of plastic deformation of the metal. On the calibrating part of the tap there is a thread with flat-cut tops, and in

transitional zone - with portions gradually changing from rounded to flat-cut

The length of the transition zone is determined by the expression

 0.5 (d -dT) + (0.04 -0.06) P

sin p where d is the outer diameter of the tap, mm;

dT-diameter of the front end of the tap, mm;

P - tap thread pitch, mm:

p - angle of inclination of the intake of the tap, hail.

Tap works as follows.

During the direct course, the intake part 1 begins to penetrate into the metal, squeezing out and gradually deepening the height of the threaded groove. As the work progresses, the calibration part 2 enters the work, which

(

CO XI

yu go

finally forms the thread profile. During the reverse stroke, the tap ejects from the machined, thread.

The presence of rounded-shaped vertices on the most loaded turns of the intake part and the transition zone of the tap facilitates plastic deformation during thread extrusion and increases the service life of the tap. The final processing is carried out by turns of the calibrating part with flat-cut vertices, which ensure the accurate formation of the thread profile.

Claims (2)

Claim 1. Bleedless tap comprising a pick-up part, calibrating part with flat-cut tops of the thread profile and shank, characterized by that, in order to increase durability by improving the conditions of deformation, the intake part is made with apexes of a rounded profile, and between the calibrating and intake parts there is a transition zone with apexes of the profile that gradually transition from a rounded to a flattened one. 2. Tap according to claim 1, characterized in that the length of the transition zone I is determined by the dependence I 0.5 (d -) + (0.04 - 0.06) P sin y where o is the outer diameter of the tap, mm; dr - diameter of the front end of the tap, mm; P - tap thread pitch, mm; p - angle of inclination of the intake of the tap, hail.