SU872081A2 - Method of making taps for cutting precision thread - Google Patents

Description

(54) METHOD OF MANUFACTURING / HETCHIKES FOR CUTTING ACCURATE THREAD

I

The invention relates to metal working and can be used in the manufacture of taps that transmit accurate threads.

According to the main author. St. No. 580954 discloses a method for manufacturing taps for cutting exact threads, the sides of the intake cone teeth of which are provided with leading surfaces located below the cutting edges at a distance slightly exceeding the thickness of the metal layer being cut, in which the leading surfaces form a single-thread grinding wheel with a thread profile angle, the smaller the angle of the profile of the thread (1).

The disadvantage of the known method is that with a symmetrical arrangement, the profiles of the grinding wheel machining the leading surfaces relative to the profile of the thread being machined have the lengths of the side edges of the teeth of the intake cone being different | 1 and the average diameter on the marker is underestimated. When tapping a thread with such a tap on each tooth of the intake cone from different sides, the cutting conditions are not the same: on one side of the tooth, the leading surface comes into contact with the thread profile, and the cutting edge comes into contact with the other side. As a result, in the presence of axial forces acting on the tap, cutting of the thread profile is possible. When using this method of manufacturing taps, the latter do not provide threading of the degrees of accuracy 4Н5Н according to GOST 16093-70 and are unsuitable for preliminary thread cutting in threaded gauges - rings

, 0 according to GOST 18465-73.

The purpose of the invention is the automatic alignment of the values of the side cutting edges of the grinding wheel profile.

The goal is achieved by displacing the grinding wheel in axial and angular directions relative to the side cutting edges of the taps.

FIG. Figure 1 shows a diagram of the formation of leading surfaces on the teeth of the tap inlet cone with axial displacement of the profiles; in fig. 2 is a diagram of the formation of leading surfaces on the teeth of the intake cone of the tap with a grinding wheel, half of the profile angles of which have different values.

The top of the profile (Fig. I) of the grinding wheel 1 is shifted from the axis of the profile of the cutting edges of the tap 2 towards the shank in the axial direction on the ve, the shape A of the POS. The leading surfaces AM and CM are formed, and the side cutting edges AB and CD have equal the magnitude of the heights measured normal to the intake cone line.

The half angle of the profile of the grinding wheel D (Fig. 2) is not equal to the half of the angle of profile D. The width of the grinding wheel I lies on the axis of the trough of the thread of the tap 2. In this case, the leading surfaces CN and the side cutting edges G AB and CD are equal to each other the magnitude of the heights.

With an axial displacement of the profile of the grinding wheel (Fig. I) relative to the profile of the cutting edges, the value of the cutting edges AB and CD are equal provided that the value of the axial displacement is determined by the formula

.sinfa Sinat / 2.

R

Te "()

where P is the thread pitch;

J- - the angle profile of the side cutting edges;

; 3 - angle angle of the grinding wheel;

L- angle of the intake cone tap.

at the angular displacement of the profile of the grinding wheel (Fig. 2), the sizes of the cutting edges AB and CD are equal in height, provided that the half angle of the profile of the grinding wheel on the side of the shank is determined with the other half of the angle URf selected by the formula

and arctptl iij i / -iiAL.

 one

. R,

Example. MZOx x3 taps are made 5 for cutting metric threads with the angle of the intake cone Mj.-6 ° 15.

When the angle of the profile of the grinding wheel; 3 50 ° axial displacement was D Ro € 0,0153mm. Measurements show that the side cutting edges turned out to be the same in size.

The use of the invention makes it possible to automatically align the side cutting edges on all the teeth of the intake cone, to determine the manufacturing parameters of the manufacturing process for any sizes of taps analytically using the formulas given, thereby eliminating the high costs of auxiliary time.

Claims (1)

Invention Formula The method of making 1 taps for cutting exact threads by ed. St. No. 580954, characterized in that, in order to automatically equalize the values of the side cutting edges, the profiles of the grinding wheels that process the leading portions of the teeth of the taps are mixed in axial m and angular directions relative to the side cutting edges of the taps. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 580954, cl. In 23 G 5/06, 1977.