SU1268395A1 - Tool for dressing multithread thread-grinding wheels - Google Patents

Abstract

TOOL FOR EDITING MULTI-GRINDERING REARSHINE CIRCLES, comprising a housing of Figure 1 with a diamond-bearing layer located on it with a working surface having the form of annular grooves of an angular profile, characterized in that, in order to improve the accuracy of editing the profile of abrasive circles for grinding small threads, the grooves of fine threads, have grooves of fine threads, and grooves of fine threads will have holes and grooves of small threads and grooves. of several elements in the form of segments that are displaced one from the other in the axial direction by the value of a in accordance with the inequality 2-rcos- | . where r, p is, respectively, the radius of rounding of the depression, the angle and step of the profile of the right tool. 2 1 J

Description

The invention relates to the editing of abrasive wheels for grinding the profile of thread grinding tools.

A known tool for straightening multi-threading grinding wheels, containing a housing with a diamond-bearing layer located on it with a working surface, has the shape of the end grooves of an angular profile.

The disadvantage of this tool is its unsuitability for machining fine pitch threads that have small (0.20 mm or less) rounding radii that are not superior in size to the size of the diamond grains, like its roller. Since stable operation and high wear resistance of the right tool is provided only with the use of large diamond crystals of at least 500/400-400/315, the minimum rounding radii of the roller profile tops are in the range of 0.25-0.4 mm. This makes these tools unsuitable for straightening circles, polished, their threads with a pitch of less than 1.75-2 mm. In addition, the threads of such a step can be machined not with the right w, with the tool, but only with the method of electroforming with the orientation of the diamond grains. Due to the large rounding radii, synthetic rollers made of synthetic azmaz, obtained mainly by the electroerosion method, are suitable for dressing grinding wheels, starting with a pitch of 2.5-3 mm.

The aim of the invention is to eliminate these drawbacks.

This goal is achieved by the fact that the working surface of the right-hand tool consists of at least two elements that are mixed relative to each other in the main direction by the amount specified by the inequality:

..

2-r-costj

where r, ci, and p are, respectively, the radius of rounding of the trough, the angle and the pitch profile of the right tool.

FIG. 1 shows the construction of the right tool, the main section; in fig. 2 - the same, side view; in fig. 3 is a diagram of the editing of the multi-thread circle and the treatment of the thread of the product.

The right tool (Fig. 1) consists of two elements 1, assembled together on the mandrel 2 and forming a cylindrical body as a whole, having a gap of 0.3-0.5 mm in the axial plane. Each of the elements also contains a diamond-bearing layer 3, and its working surface is made in the form of annular grooves of a corner profile with a tongue that is a multiple of the grinding thread. One of the roller elements is offset relative to the other by the amount specified by the expression

/ -cos | ,

where r, yC, and p are the radius, yo.t, and the pitch profile of the right tool, respectively.

Axial displacement of elements can be adjusted in the process of their wear or set

constant, taking into account the increase in the radius of rounding of the profile caused by the wear of the right tool.

Another example of a possible embodiment of a roller is the fastening on the body of several diamond elements made in the form of rectangular bars or segments having the required profile, which are arranged in a checkerboard pattern and displaced relative to each other by a specified amount. Thus, the working surface of the tool,

formed by a group of elements with even numbers, turns out to be offset with respect to the surface of elements with odd numbers.

In the editing process (Fig. 2), one of the elements (or a group of elements) of the right roller 4 forms a coil with a profile ABDC on a multi-line circle 5, the radius of which rounding along the top corresponds to the radius of rounding of the depression of the roller 4 according to the inner diameter.

If the profile on the circle 5 were formed only by the second element (the second group of elements), then it would have the same shape (ADBC), but shifted relative to the profile ABDC by some fixed value a. Since the editing process

both profiles are formed alternately, then finally the ADC profile will be obtained on the circle, which is the result of their overlap.

The resulting circle profile differs from the roller profile in that, regardless of the amount of rounding of the roller root, it has a sharp vertex. If we grind the thread of a smaller (multiple) pitch with such a circle, then, as can be seen from FIG. 2, on the product 6, a profile with minimal

rounding, both at the top and at the bottom of the thread, regardless of the size of these roundings at the right tool.

The offset of the elements of the roller 4 relative to each other should be carried out on the width of the area of the profile of the depression of the roller in the inner diameter (g cos-)

subject to subsequent wear. At the same time, the pitch profile circle is equal to the pitch profile of the right roller.

From the point of view of the operational durability of the grinding wheel, the most preferable is the amount of displacement equal to one half of the roller.

In this case, a profile is formed on the circle with a step twice as small as the step of the roller, which increases the number of working threads of the circle and its durability. The choice of a specific mixing value depends on the size of the profile of the roller and the size of its rounding. If the radii of rounding of the roller tips are such that the height of the resulting profile is greater than the height of the thread to be ground, the offset value is chosen equal to half the step. In other cases, it is chosen equal to the width of the pad in the roller cavity, taking into account its subsequent increase due to wear. Thus, the magnitude of the offset lies within

r-cos- - p

The tool is tested for threading taps of steel with a diameter of 6 mm and a step of 0.5 mm. A cylindrical right-handed roller with a diameter of 80 mm and a width of 20 mm made of synthetic diamonds on an adhesive-active bond is cut along the axial plane on an electric spark machine with a wire electrode. After assembly on the mandrel, the roller is profiled by the EDM method on a machine tool with a graphite electrode. The pitch of the resulting profile is 2 mm.

the profile angle is 60 °, the radii of the top are 0.2 mm and the trough is 0.3 mm. Using shims, one half of the roller is offset relative to the other by 0.4 mm. Roller

set in the device for editing on modes Vxp 40 m / s, Vp 7 m / s and transverse feed 1 mm / min. On counter revolutions of the circle and roller, the abrasive circle of software 400X20X203 24A 4 S1K6 is right. The result is a multi-line circle with

with a pitch of 2 mm, a profile angle of 60 ° and a radius of rounding of the vertex of 0.03 mm. The thread is ground in a single pass at a speed of 40 m / s and a product rotation speed of 0.3 m / min. The control of the ground thread showed that it meets all the requirements for profile geometry.

Testing of similar clips of conventional design, also obtained by the electric spark method, conducted on the same flock and under the same modes, showed that

in connection with the large rounding of the profile, the minimum thread pitch that can be processed with their use is 2.5 mm. Thus, the proposed tool makes it possible to obtain a multi-thread grinding of the product with fine steps, irrespective of the size of the right tool profile.

1rig.2

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Claims (3)

TOOL FOR EDITING MULTI-FREQUENCY THREAD-GRINDING CIRCLES, comprising a body with a diamond-bearing layer located on it with a working surface having the shape of annular grooves of an angular profile, characterized in that, in order to improve the accuracy of editing the profile of abrasive wheels for grinding small threads, the working surface is made of several elements in the form of segments displaced one relative to the other in the axial direction by a in accordance with the inequality 2-g cos-tg <° ’where r, <k, p are the radius of rounding of the depression, the angle and the pitch of the profile of the ruling tool, respectively. FIG. 1 2 1 3 (L 1268395 A1