SU1456265A1 - Drawing die - Google Patents

Abstract

The invention relates to the processing of metals by pressure and can be used in mechanical engineering in the manufacture of hollow articles by extrusion. The purpose of the invention is to improve the quality of the products being stretched by ensuring their uniform thickness. Between the matrix 1 and the clamp 2 there is a stop 4 of the clamp 2 stroke, designed as a ring with a height equal to the difference in the transverse dimensions of the die 1 and the working part of the punch 5. The tip of the clamp 2 is located above by the interface of the exhaust edge and the pressing surface of the matrix 1, the height of the protrusion is equal to half the height of the ring. This arrangement of the protrusion leads to the fact that the braking of the flange of the billet is carried out not from the very beginning of the stretching, but from the moment when the flange of the billet gets thickened, and the height of the stretched part of the billet is significant. Consequently, there will be a large area of contact between the punch 5 and the workpiece, on which useful forces arise that prevent thinning of the product wall. 4 il. (L

Description

Phie.

The invention relates to the processing of metals by pressure and relates to dies for drawing.

The purpose of the invention is to improve the quality of the parts being pulled out by ensuring their thickness.

1 shows a stamp, a general view, a longitudinal section; 2 - the same, at the intermediate time of drawing on fig. 3 - the same, with a hydromechanical matrix, with the initial position to the left of the axis of symmetry, the intermediate position to the right; Fig. 4 is the same with the hydromechanical matrix at the time of the completion of the stretching process.

The stamp contains a rigid matrix 1, a flat clamp 2 with a protrusion 3 on a clamping surface located equidistantly contour in terms of the working hole of the matrix 1. The protrusion 3 can be made integrally with the clamp 2 or plug-in. Between the matrix 1 and the clamp 2, the limiter 4 of the clamp 2 stroke is placed in the form of a ring with a height equal to the difference in the transverse dimensions of the opening of the matrix 1 and the working part of the punch 5 (in the particular case of cylindrical punch 5 and matrix 1, the difference of their diameters). The tip of the protrusion 3 of the presser 2 is located above the interface of the exhaust edge and the presser surface of the matrix 1, and the height of the protrusion 3 is equal to half the height of the ring 4, i.e. the tip of the protrusion 3 of the pressing 2 is located from the matrix 1 at a distance equal to the initial (initial) thickness So of the workpiece 6.

In the die with hydromechanical matrix 1 (Fig. 3 and 4), before starting the stretching, its cavity is filled with working fluid 7, and limiter 4 of pressure stroke 2 is made with channels 8.

The stamp works as follows. On the matrix 1 (Fig. 1, left), lay the stamped workpiece 6 with a thickness of SP and lower the presser 2 onto the ring 4. At the same time, the tip of the protrusion 3 of the presser 2 is spaced from the pressing surface of the matrix 1 to the thickness So of the workpiece 6, just touch it. After that, the movement of the punch 5, which draws the workpiece 6 into the working opening of the matrix 1, is reported. Since the workpiece 6 is not pressed at the same time (the flange does not brake), at the initial stage of drawing, the workpiece 6 slides freely between the pressing surface of the matrix 1 and the protrusion 3 of the clamp 2 encompasses the radial part of the punch 5 and the radius r of the rounding of the die opening 1. In the absence of braking of the flange of the bottom and the wall of the workpiece 6, the flange does not actually occur. As a result, the elongated part of the blank 6 has a thickness of 8d, i.e. equal to the initial thickness of the workpiece 6. Here the effective friction forces on the contact punch 5 - workpiece 5 and 6 also begin to act, as well as preventing the last initial thickness 8 from remaining. These forces are caused by the fact that there is no gap between the punch 5 and workpiece 6 ; blank 6 tightly covers the punch 5.

The free slip of the workpiece 6 continues until the beginning of the second stage of drawing (Fig. 1, right), when the flange section, which received a thickening under the action of compressive tangential stresses, approaches the protrusion 3 of the presser 2. From this moment until the end of the drawing process, the flange of the workpiece 6 is braked by dragging it through the gap formed by the protrusion 3 of the presser 2 and the pressing surface of the matrix 1 and equal in magnitude to the initial thickness So of the workpiece 6. Herewith (FIG. 2) the thickness of the flange, which received a thickening during stretching, is forcibly reduced to the value S ,,, i.e. to the initial thickness of the workpiece 6.

When drawing, the tensile stresses in the stretched part of the workpiece 6 increase somewhat. However, due to the fact that the stretched part of the workpiece 6 retains the initial thickness So, has no weakened sections, the contact 6 useful frictional forces that prevent wall thinning, further wall thinning of the finished product (not shown) does not occur.

The thickest part of the flange of the workpiece 6 is subjected to drawing at the very end of shaping, when a large part of the product wall is formed, and with a large product wall length, the contact area of the punch 5 - workpiece 6 increases as much as possible. on this contact preventing a decrease

wall thickness versus initial s.

The maximum use of these useful friction forces is achieved due to the fact that the tip of the protrusion 3 on the clamp 2 is located above the junction line of the exhaust edge and the clamping surface of the matrix 1. If the tip of the protrusion 3 of the clamp 2 were located above the flat part of the clamping surface of the matrix 1 closer to the periphery the workpiece 6, then the drawing of the most thickened part of the flange. would start earlier along the course of the punch 5, when the height of the stretched part of the workpiece 6 would be still small, respectively, the contact area of the punch 5 - would also be small blank 6 and useful friction forces on this contact surface. Moreover, the farther from the center of the workpiece 6 would be the protrusion 3 on the clamp 2, the earlier the flange drawing would begin and the useful frictional forces on the contact of the punch 5 — the workpiece 6 — would be used less, the greater would be the danger of reducing the wall thickness of the product against the initial thickness S blanks 6.

After the product has been completely molded, the punch 5 and the presser 2 return to their original position and the drawing cycle is repeated.

The work of a stamp with a hydromechanical matrix is almost the same as stated. The only difference is that before the start of drawing, the cavity of matrix 1 is filled with working fluid 7 (lubricant), which during the drawing process is displaced through the drawing gap and further through channels 8 in limiter 4 of the pressing 2 stroke. Due to the backpressure of the lubricant, in this case the drilled forces of friction on the contact punch 6 I increase

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1456265 -

. the workpiece 6 and the braking of the flange on the contact is reduced; the workpiece 6 is pressed against the surface of the die 1.

The stamp with both rigid and hydromechanical matrix 1 allows to obtain products with minimal deviations of the bottom and walls thickness from the initial thickness of the workpiece 6. Obtaining such products allows excluding additional machining operations from the process, thereby increasing the productivity labor and provide savings in metal. The stamp is suitable for drawing cylindrical, box-shaped and complex shapes in terms of details.

Thus, the proposed stamp allows improving the quality of the stretchable products by ensuring their equal thickness.

Claims (1)

Invention Formula A drawing punch containing a core-mounted punch and a die with a working hole, as well as a clamp with an annular protrusion on the working surface located equidistantly to the contour of the working hole of the die, characterized in that their equal thickness, it is provided placed between the matrix and the clamp limiter of the clamp, made in the form of a ring with a height equal to the difference of the transverse dimensions of the working hole of the matrix and the working part of the punch, on the protrusion protrusion is located above the interface of the exhaust edge and the presser surface of the die, and the height of the protrusion is equal to half the height of the ring.  "L r fs 3. about P 5 .З R s .