RU2354487C1 - Tool for thread cutting - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to pressurised metal treatment, and particularly, to thread cutting tooling. The tool includes movable and fixed dies, each having intake, calibrating and derailing sections. No more than 0.3 mm deep dimples are made on the top and side surfaces of the upper thread profile on the half of intake section from dies ends. The dimples are made by spark erosion fabrication method.

EFFECT: increase stability of tool.

2 dwg

Description

The invention relates to the processing of metals by pressure, in particular to thread rolling, and can be used when rolling external threads with dies.

Known dies for rolling threads with a height-polished profile of thread-forming threads on the intake site (see USSR AS No. 63681, class 7f9 dated 06/30/1944).

The disadvantage of this die is that in the initial stage of thread formation, the contact of the metal with the most blunted profile of the thread-forming threads is much greater than on its lateral sides. This condition of metal contact at the tops and sides of the thread-forming threads does not provide reliable adhesion of the rolled part to the tool, which leads to slipping of the workpiece relative to the tool. In the presence of slippage, the resistance of the thread rolling tool decreases and the time spent on setting it up increases.

The closest in technical essence to the claimed invention is a thread rolling tool, on the intake sections of which transverse grooves of a triangular shape are made (see AS No. 1186339, class B21H 3/06 of 11/30/1983).

The main disadvantage of the known thread rolling tool is that such a tool dramatically reduces the quality of the thread being rolled. On the lateral surfaces of the thread profile rolled by such a thread rolling tool, defects remain in the form of shells, folds, burrs.

The present invention is aimed at increasing the resistance of the tool for rolling threads by eliminating the phenomenon of slipping of the workpiece relative to the die without reducing the quality of the rolled thread.

The problem is solved in that in the tool for rolling threads containing movable and fixed dies, each of which has an intake, calibrating and dropping sections, according to the invention, on the half of the intake section, starting from the end face of the dies, numerous small craters obtained by the electrospark method are made, a depth of not more than 0.3 mm on the tops and lateral surfaces of the upper half of the thread profile.

The invention is illustrated by drawings. Figure 1 shows the movable and fixed dies in longitudinal section. Figure 2 shows the thread profile of the dies.

Tool for rolling threads works as follows. When the working stroke S of the movable die 1, the workpiece 3 is fed into the rolling zone. Thread-forming threads in the first half of the intake sections 4 of the movable 1 and fixed 2 dies are gradually introduced into the body of the workpiece, giving it rotation and translational movement relative to the tool due to friction forces arising in small craters, first at the tops and then on the side surfaces of the thread profile. And the deeper the dies are introduced into the body of the workpiece, the greater the friction forces rotate the workpiece. The rotating workpiece smoothly passes into the second half of the intake sections of 5 dies, where minor defects of the threaded profile of the thread being rolled are corrected.

Thus, the dies of the proposed design sharply increase the resistance without compromising the quality of the rolled thread.

Claims (1)

A tool for rolling threads containing movable and stationary dies, each of which has an intake, calibrating and dropping sections, characterized in that on the tops and lateral surfaces of the upper half of the thread profile of the half of the intake section located from the end of the dies, numerous small craters are made by the spark method depth not more than 0.3 mm.

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