SU1090513A1 - Chipless tap - Google Patents

Abstract

1. BETTING-METER, on the outboard part of which the vdt threads are made symmetrical with respect to the tops of the turns of the resulting thread, characterized in that, in order to increase tool life and the accuracy of the threads produced, the turn profile of the thread turns is greater than the angle of the thread obtained and gradually decreasing to the beginning of the gage parts. 2. Tap according to claim 1, characterized in that the angle of the thread profile of the intake part is determined by the dependence σ (arcsin.. A (

Description

This invention relates to metalworking and can be used in the preparation of internal threads.

Taps are known in which the angle profile of the threads on the intake portion is made larger than the angle of the profile of the thread obtained and gradually decreases towards the beginning of the gage part 1.

A disadvantage of the known taps is the asymmetry of the angle of the profile of the coils relative to the top, which causes unbalanced axial forces in the threading process, as a result of which the threading profile is cropped, i.e. its accuracy is reduced.

The purpose of the invention is to increase the tool life and the accuracy of the threads produced.

The goal is achieved by the fact that in a brushless tap, on the intake part of which the threads are symmetrical about the tops of the turns of the resulting thread, the angle profile of the thread turns is greater than the angle of the obtained thread and gradually decreasing towards the beginning of the calibrating part.

In this case, the angle profile of the threads of the intake part is determined by the dependence

eigf

 2arcsin

VP 4-4lO, 866p-ttgfP

"A-angle profile of the obtained thread;

t is the distance from the beginning of the calibrating part to the top of the considered thread coil of the intake part;

P is the angle of inclination of the thread turn of the intake part along the outer diameter;

P - thread pitch.

The drawing shows the threads of the intake part of the tap and the part of the turns of the gage part.

The tap consists of intake 1 and 2 parts calibrating.

Coils 3-8 threads intake have

corrected profile. Profile angle

turns d is made more angle profile

at the obtained thread and in general form is defined by the above formula.

Tap works as follows. Initially, turn 3 enters the work. It begins to profile the thread groove with the angle of the profile. When axially moving, the next turns of the intake part enter into the work, deepening the thread groove and changing its profile, which as the turns of the calibrating part get closer and closer to the profile of the resulting thread. The coils of the gage part finally form the thread. The execution of the thread turns of the intake part by the corrected allows them to be performed without a bias on the inner diameter, which increases strength, simplifies

5 manufacturing technology. The coils are symmetrical about the vertices, which balances the load on the left and right sides of the coils. The pitch of the thread on the calibrating part remains unchanged and equal to the pitch of the turns along the tops on the intake part, i.e. eliminates the disadvantage of all chipless tap with full thread on the intake part. All this makes it possible to eliminate the "thread breaking.

Claims (2)

1. A DRAWLESS TAPE, on the outboard part of which the threads are made symmetrical with respect to the vertices of the turns of the resulting thread, characterized in that, in order to increase the tool life and accuracy of the threads obtained, the angle of the thread turns is made large by the angle of the obtained thread profile and gradually decreases towards the beginning gauge part. 2. Tap on π. 1, characterized in that the angle of the profile of the threads of the thread of the intake part is determined by the dependence "= <1 + 2 arcsin j-p,, where ° C is the profile angle of the obtained thread; £ is the distance from the beginning of the calibrating part to the top of the considered thread thread of the intake part; 'P-angle of the slope of the top of the threads of the intake part along the outer diameter; P is the thread pitch. Ltd Joint venture with vacm /> i090513