SU1368108A1 - Threading die for cutting thread with variable external diameter - Google Patents

Description

FIG.

eleven

This invention relates to metalworking and can be used in threading.

The purpose of the invention is to improve the quality of the thread being cut by ensuring that the load is evenly distributed over the turns by cutting a two-step thread with a variable turn thickness.

Figure 1 shows the proposed die, General view; figure 2 is a view of And figure 1; Fig. 3 is a diagram of the formation of a two-step thread with a variable tooth thickness; figure 4 - types of two-step thread, which can be cut with a die.

The die is a modular threaded tool containing an external inner 2 die installed therein. Pen 3 dies 1 are placed between the feathers 4 dies 2, alternate with them. The die 2 is mounted for axial movement relative to the die 1 by using, for example, a sliding key 5.

The dimensions of the thread pitch on the feathers x 3 plates 1 and on the feathers x 4 plates 2 are determined from the mathematical relationships

P p (1 - 2-4.). 1 ctg /

P, 2P - P

one

P step cut thread; thread pitch of the first plate;

thread pitch of the second die;

half the angle of taper of the outer diameter of the thread being manufactured; angle thread profile. When cutting the threads of the plate, oddly the cutting dies cut into it, the second cuts off one of the profiles and threads. Since ub on pen x 3 and 4 dies 1 and 2

R. P, H d

feathers threading the second side of the thread profile to be made.

The variable value of the allowance taken by the second die ensures the formation of a variable outer diameter and a variable thickness of the turns of the cut thread. The change in the outer diameter and thickness of the coils is cyclical, which makes it possible to form threads with decreasing or increasing values at a given thickness of the workpiece or threads that have the largest or smallest values of the outer diameter and thickness of the coil which are located in the middle of the sections of a given length, or the thread that has Several cycles of decreasing and increasing their values are placed on a given length of the threaded section. The greatest thickness of the thread being cut corresponds to the largest value of its outer diameter, which is related to the outer diameter of the die threads by the ratio

Dn

D + 0.5p (Pj - P-,) ctgo.

g

five

five

one

D p 0 0

where D is the outer diameter of the thread dies;

the largest outer diameter of the cut thread; the number of turns in the cycle of increasing or decreasing the outer diameter of the cut thread;

dies thread steps; angle thread profile. The internal diameter and pitch of the thread being cut are constant, and the pitch of the thread being cut is equal to the arithmetic average of the thread pitch on the dies.

I

Due to the fact that

threading a die having a larger thread pitch overtakes the die with a smaller pitch; when preparing the tool for operation, the die with a large thread pitch is shifted in the axial direction

a different pitch, an allowance taken by the second 50, so that its feather starts cutting with a die, increases or decreases from a turn (depending on the ratio of steps and initial setting of the dies). As a result, the two-step thread is cut, since one hundred -55th of its profile is cut with thread with a thread that has a step different from the step.

with a lag on the number of turns equal to the number of cycles of increasing or decreasing the outer diameter on the length of the treatment. In this case, the axial position of the dies at the end of processing is the same, which eliminates undercutting.

so that her feather began cutting

with a lag on the number of turns equal to the number of cycles of increasing or decreasing the outer diameter on the length of the treatment. In this case, the axial position of the dies at the end of processing is the same, which eliminates the undercut of the thread.

J.

one

I I I I I (

FIG 2

Fig.Z

Fy

Claims (1)

DIESEL FOR CUTTING THREADS WITH A VARIABLE EXTERNAL DIAMETER, containing threaded feathers, characterized in that, in order to improve the quality of the cut thread, the die is made of a team of two round dies, which are installed one in the other with the possibility of relative axial movement, and the thread pitch on the feathers the first die is different from the thread pitch on the feathers OS OS OS