CS226264B1 - Method of and apparatus for hydromechanical drawing of deep shells with thinned walls - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a method for hydromechanical drawing of deep extracts with thinned transitions of a pressurized chamber and graduated internal chamber cross-sections filled with at least a portion of a liquid filling.

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The hitherto known drawing methods and apparatuses used for the manufacture of hollow deep molds with wall thinning either by successive molding on a number of tools placed on expensive molding machines or by molding on several presses, in both cases the in-process annealing of the individual intermediate extracts. The drawing methods outlined are characterized by high investment and operating costs.

Another possible method of making hollow deep-walled wall-thinners is to transform the initial sheet metal blanks into a cup-like shape in the traction tool and then draw them with a thinning of the wall over the tension ring. In this case, it is necessary to select a starting material of relatively large thickness, and to achieve a relatively thin wall of the final extract, several successive reductions in the tension rings arranged in the tool body with the necessary forced cooling are required.

The drawbacks are eliminated by the method of drawing the extracts by the thin wall according to the invention, which consists in that the sheet metal blank is pulled into the chamber of the pressure chamber by simple pulling until the bottom of the resulting extract is sealed with liquid.

The filling at the bottom of the pressure chamber is then applied to the bottom of the formed extract by a punch by applying the pressure of the liquid filling until the extract is simply drawn through a tapered profile above the liquid filling of the pressure chamber. punch.

It is particularly advantageous to provide a pressure chamber arrangement for carrying out the method according to the invention which is mounted in at least two mutually separable stages, the lower stage being filled with a liquid filling and wherein a tension ring is inserted between the two stages of the pressure chamber.

The achieved positive effects of the invention are manifested in the deep drawing process, in particular in that the main values of the press functions can be controlled throughout the drawing process. The first simple drawing with the retainer allows the formation of a deep and relatively thin-walled extract without a flange, and then a continuous successive stretching of the extract over the pull ring causes thinning of the wall and elongation of the extract. The stretching is preferably carried out under the action of the pressure of the liquid filling, thereby exerting an additional force on the punch, thereby increasing substantially the friction between the punch and the punch, thereby reducing the tensile stress in the punch so that the final achievable values when the punch is deformed. In addition to these effects, the device according to the invention allows a number of other applications of drawing methods, such as drawing with a thin wall without liquid filling, simple hydromechanical drawing and the like.

Further effects and advantages of the invention can be seen from the following description of an exemplary embodiment of a device suitable for carrying out the method of the invention and from the drawings, in which: Fig. 1 is a sectional view of a pressure chamber with spaced apart steps; .2 the stage of simple drawing of the sheet metal sheet in the upper stage until the liquid filling is sealed through the bottom of the extract; FIG. 3 the phase of stretching the extract of simple drawing through a tapered profile over the liquid filling of the pressure chamber; and sliding the thin wall wall into the removable bed.

The device for carrying out the method according to the invention consists of a pressure chamber 1 with an interior space mounted in at least two mutually separable stages, wherein the lower stage 2 is filled

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The upper stage 4 is connected to the β holding plate 5 by means of hinged cups allowing the mutual ace movement of the two means 6 and 2 so that the upper stage 4 forms a punch for simple drawing. to allow the sheet metal blank 6 to be inserted therebetween in the position in which the abrasive means 8, 6 are moved away from the lower stage 2 of the pressure chamber 1 (FIG. 1).

Bottom βtupen 2 is provided at its upper edge with a seal 7 and at its bottom is provided with an opening 8 for controlled draining of liquid filling J, or for filling this lower stage 2 with liquid filling J after the end of working cycle. thinned wall.

A tension ring 10 is provided between the two stages 2, 6 of the pressure chamber 1, which in the exemplary embodiment is mounted on the upper stage 6 of the pressure chamber 1. The tension ring 10 narrows the profile or changes the cross-section of the inner space of the pressure chamber 1. In the upper step 6, a draw-through opening 12 is provided by the pulling ring 10 for draining the excess liquid filling 2 and for venting.

The function of the described drawing apparatus according to the invention is as follows: A sheet metal blank is inserted between the holding plate 2 by the upper stage 4 of the pressure chamber 1, and then, for example using the press holding bracket (not shown), The two stages 2, 6 are then firmly clamped together and sealed with a gasket.

The filling of the liquid filling up to the overflow opening 12 is carried out and the drawing of the blank 6 is started by the punch 11 l under simple drawing conditions in the upper stage 6 of the pressure chamber 1 until a flange-free extract 13 is obtained. charge 5 in the lower stage 2 of the pressure chamber 1 (FIG. 2) ·

By further movement of the punch 11, the extract 13 extends through the pulling ring 10 i1 by the action of the pressure of the liquid filling J in the lower stage 2 of the pressure chamber 1, whereby the wall of the extract 1 is substantially thinned from a simple drawing and at the same time its length increases (FIG. 3). 13, the pressure of the liquid cartridge J is controlled by a pressure relief device (not shown) connected to an opening 8 at the bottom of the pressure chamber 1. After completely extending the extract 13 over the pulling ring 10 to form the extract 14e through the thinner wall according to the punch 11. from the lower stage 2, the upper stage 6 with the pulling ring 10 is lowered by the lower ejector 9 into the removal position for further manipulation (FIG. 4), the whole device being brought to the position for pulling another sheet metal blank 6. '

Claims (2)

SUBJECT OF THE INVENTION A method of hydromechanical drawing of deep extracts with a thinned wall in a pressure chamber with graduated cross-sections of an interior space filled at least partially with a liquid filling and at least one punch of sheet metal sheet based on the upper edge of the pressure chamber. the blank is simply pulled by the puncher into the chamber of the pressure chamber until the bottom of the resulting seal seals the liquid charge at the bottom of the pressure chamber, and then the bottom of the resulting extract is acted on by the puncher. and being pulled out with the thinned wall to the final shape according to the punch. 2. Apparatus for carrying out the method according to item 1 with a pressure chamber having an interior space mounted at least in two stages mutually separable, wherein the lower stage is filled with a liquid filling, while the upper stage forms a simple drawing die and is provided with a sheet-metal sheet holding plate a ram, characterized in that a tension ring (10) is inserted between the two stages (2,4) of the pressure chamber (1).