SU664727A1 - Method of making tapering thread - Google Patents

Description

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The invention relates to the processing of metals by pressure and can be used in the manufacture of threaded conical products.

There is a known method of rolling a tapered thread with thread-cutting heads, according to which tapered thread rolling rollers installed in the head with the axes crossed relative to the workpiece are moved along the generatrix of the thread cone while rolling the thread on the workpiece in successive sections 1.

The disadvantage of this method is low productivity and the fact that thread rolling occurs when the axial spacing of the rolling rollers continuously changes, which imposes increased demands on the accuracy of the rollers moving at high rolling forces. This ultimately causes the thread profile to deviate.

The closest solution to the technical essence of the invention is a method for producing conical threads, in which a conical billet is rolled simultaneously along the entire length of a threaded conical rollers when moving them along the axis of the workpiece while maintaining a constant distance between the axes of the rollers and the axis of the workpiece 2.

The disadvantage of this method is the low quality of the obtained thread.

In the proposed method, this disadvantage is eliminated due to the fact that after rolling the workpiece is rolled on the same rollers, moving them in parallel with the forming cone of the workpiece.

FIG. 1 shows a schematic of a method at the time of thread rolling; in fig. 2 -

the same, but at the time of thread calibration; in fig. 3 - the same, but at the time of thread calibration rollers made with intake cone. Several thread rolling rollers 1 s

annular threaded grooves are installed evenly around the workpiece 2 with a certain skew angle relative to its axis (in the plane perpendicular to the plane of the drawing).

The rollers in the rolling process have axial movement (along arrow A), and in the process of rolling, they move along the generator of the cone (along arrow B).

The rotation drive is carried out through

billet or through rollers.

According to the invention, the rolling is carried out as follows. The thread rolling rollers 1 are fed axially (along arrow A) onto the rotating workpiece 2 at a speed agreed upon.

with the rotation of the workpiece. As a result of the interaction of the rolling rollers and the workpiece, the workpiece is seized by the rollers and the thread of the full profile is rolled on it with a compression of 0.03-0.15 mm / rev.

Thus, during the entire thread rolling period, the center distance of the knurling rollers is kept constant, which favorably affects the accuracy of the rolled thread.

At the end of the thread rolling of the full profile, the knurling rollers begin to move along the generatrix of the thread cone (in the direction of arrow B), due to which the run-in occurs without crimping the metal, and the workpiece makes 1.5-3 turns.

Since during the running-in of the thread, the forces of deformation sharply fall, the mechanism for the coning of the thread-rolling head will work under more favorable loading conditions, and thus a higher-quality thread will roll.

As a tool, knurling rollers of the simplest geometry can be used - with circular coils of a full profile, i.e., without an intake cone. In this case, the width of the rolling rollers will be maximum, determined by the formula

about I I 1 /

- / and -: h to

2tgf

where / is the length of the tapered thread

full profile; 3 - diameter of the workpiece in the main plane;

d-BH is the inner diameter of the thread in the main plane; F - the angle of the taper of the thread; i, j (3-4-4) 5- the length of the calibrating part; S is the pitch of the thread being rolled. In order to reduce the width of the rolls to some extent, as well as when the threads are not rolled forward, the rollers should be made in the form of a double truncated cone, including the intake cone and a section with reverse taper (Fig. 3). In this case, the width of the rolling rollers. Is determined by the formula

5 / -f- / zk. ,

where / zk is the length of the intake cone section.

The proposed method of rolling tapered threads will allow rolling high-quality tapered threads, since the rolling of the thread profile, accompanied by great efforts, is carried out at a constant center distance of the rollers.

The movement of the thread rolling rollers along the generatrix during the calibration process takes place at lower rolling forces, which ensures high quality tapered threads.

The proposed method can roll both external and internal tapered threads.

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Claims (2)

1. USSR author's certificate number 313597, cl. B 21N 3/04, 1970. 2. Sultanov TA Rezbonakatnye heads. Mechanical Engineering, M., 1966, p. 106