CS224186B1 - Tap with internal hole - Google Patents

Abstract

By the single-cut tap for obtaining optimum surface roughness of both flanks of a cut thread, the finishing cut is not made gradually over the height but all at once over the entire width, which is equal to the flank length of the thread profile. At each flank, a substantial improvement in the surface roughness of the thread flanks is achieved in another groove of the thread profile.

Description

The present invention relates to a single-cutting tap with an internal bore provided with a cutting, crown formed by a cutting cone and respective grooves, wherein a first pre-cutting portion 13 with a conically stepped chip removal is arranged in the threaded portion of the cutting cone.

The invention relates to a single-cutting tap with an internal chip opening and a novel method of splitting a chip in the threaded portion of the cutting cone. The present tap solves economical cutting of precision, medium and larger through and through threaded taps

224 186

224,186 holes in difficult-to-machine materials with the main requirement for optimum roughness of both flanks of the carved threads.

The known types of single and multi-piece taps with previously known chip cutting methods used for medium and larger, preferably through holes, meet the precision requirements for threaded holes, but do not sufficiently meet the high quality roughness of the front and rear flanks of carved threads in difficult-to-cut materials required in the production of reactors, turbines, generators, machine tools, etc.

The above-mentioned disadvantages are eliminated by the single-cutting tap according to the invention, which is based on the fact that in a single tap, a new pre-cutting first, second and smoothing tap function has been constructed in a single tap. pitch). The design for the 6-tooth tap is shown in the unfolded portion of the cutting crown in Fig. 1. The inclined faces of the respective teeth at an angle of 1 produce positive cut angles cT ~ (Fig. 1) at the front sides of the teeth. threading. The lightening of the back flanks of the GH threaded teeth reduces chip congestion and the load on the respective crown teeth.

The advantage of the invention is that dimensionally accurate threaded holes can be cut economically with a single tap (even large pitches), but with better and more uniform surface roughness of both flanks of the thread than is achieved with all known single and multi-taps. The smoothing chip is not cut in stepped heights, but at once in a width equal to the length of the side of the threaded profile and at each side in a different groove of the threaded profile. This eliminates traces of stepped cutting on the sides of the cut threads.

224 186

Instead of tapping a tap according to the invention, instead of two or three sets of taps, it is sufficient to cut high-quality threaded holes of the threads. The following roughness was measured in the field testing tests performed with taps according to the invention, for example, size M85x6.6H.

For material

15CH2M1FA

U maaeriálu

08CH18N10T front side rear side rear front .bok ^'side

Ra = min 1.2

Ra = min 1.1

Ra = min 1.4

Ra = min 1.6 max 2.3 / tm max 1.2 µm.

max 2 / rn max 1.8 rpm

The measurement was carried out by a quality control center. The achieved roughness with a tap according to the invention of the size M 85 is a. o. several degrees of roughness. better than the roughness achieved by special. single and multi-member. taps. of leading-world companies. Furthermore, the possibility of thread cutting is reduced, the cost of taps is reduced,. their maintenance and wages - for the actual thread cutting.

The chip section is shown in FIG. 3 with the cutting edges M 3, the side of the tooth K, the chip 3 with the back edge of the front side of the tooth N and the chip to R.

1.a. 2,. where chips 1 are chips. 2 lip. front of the tooth. P, chip 4 br.ieem. The elements described in the present invention can be used in full or in part in other types of taps without, however, being used. this would change the subtlety of the invention.

Claims (5)

SUBJECT OF THE INVENTION 224 186 A one-cutting tap for an internal bore provided with a cutting crown formed by a cutting cone and respective grooves, wherein a first pre-cutting portion M3 with a conically stepped chip removal is provided in the threaded portion of the cutting cone. and a back side chip at a width equal to the length of the side of the threaded profile, followed by a radially smoothing and calibrating portion M1 with the removal of a smoothing front and back side chip. 2. The one-cutting tap according to claim 1, characterized in that in the precisely defined threaded teeth in the second pre-rusting part and in the subsequent calibrating part of the tap marked Sttl, their rear flank is always undercut by x у. 3 »The one-cutting tap according to item 1 and 2 is characterized in that a positive angle of the cutting edges is formed at the front flanks of the precisely defined threaded teeth R, N. AND 4. The single-cut tap according to claim 1, 2 and 3, characterized in that all the cutting stepped parts arranged on a single tap operate immediately in succession. 5. The one-cutting tap according to claim 1, 2, 3 and 4, characterized in that the teeth have a rake angle Z at least in the pitch width S, possibly increased by Z.