DE2924888A1 - METHOD FOR PRODUCING CYLINDRICAL SLEEVES - Google Patents

Description

DR. BERQ D I PL.-I NQ. STAPF DIPL.-ING. SCHWABE DR.DR. SANOMAIR

PATENT LAWYERS • MÖNCHEN IO. MAUERKIRCHER «TR.4e

Attorney file 30 172

-3-

June 20, 1979

Textron, Inc.,

Rhode Island / U.S.A.

Method of making cylindrical

pods

- Expectations -

909882/0778

Description

The invention relates to a method for extrusion and molding of cup-shaped, cylindrical Sleeves, in which a cup-shaped blank through the band of a stamp surrounding and on this along downwardly movable pressure sleeve into one of the lower end of the punch and the bottom wall of one Die limited cavity is extruded and the partially formed sleeve for forming the cylindrical peripheral wall and an enlarged upper edge is drawn further by means of at least one die without that the thickness of the bottom is changed. The extended top edge can then be in the same device removed by shearing. Under certain conditions, the pressure bushing can be made in one piece with the punch, the extrusion then being effected by the movement of the jacketed punch into the Die takes place.

In a conventional method for drawing sleeves, a cup-shaped blank is made by means of a first Stamp pressed through several stacked dies, the bottom of the sleeve is reinforced by radial compression. The partially drawn sleeve is then passed through a second assembly pressed by stacked dies to further strengthen the bottom of the sleeve and its peripheral wall to pull. The sleeve is pressed completely through the bottom die in each case and at the return movement of the punch through its lower Edge stripped from this so that it does not have an enlarged upper edge. To complete the The excess length of the sleeve must then be removed in a special operation. The described

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Procedure has i.a. the following disadvantage

The blank fed to the first die must have extremely precisely defined dimensions, since the reinforcement of the soil is not necessarily controlled during the successive operations.

There is therefore no way of precisely determining the thickness of the bottom of the sleeve in any of the dies. When the sleeve is pressed through, the matrices, which are stacked on top of each other, move their material in the axial and radial direction freely flowing to the area of the floor, so that the desired thickness of the floor only is approximately achievable by extremely precise dimensioning of the blank.

As a result of the repeated drawing process, the cylindrical part of the sleeve experiences work hardening, so that the The sleeve must be annealed before further processing.

Since the cylindrical part of the sleeve does not have a widened edge at the upper end and is repeated by the If passes through the dies have undergone work hardening, this can only be done by turning them on, for example Lathe can be shortened to the prescribed length. Because of the repeated drawing process, there is also the Risk of cracks and other defects forming on the upper part of the sleeve.

In contrast, the invention creates a method of the type mentioned, which allows an accurate determination of the soil thickness and the contours of a sleeve.

The method according to the invention does not work with the previously used, stacked Zieh'S 0 3 % 8 2/0 11 &

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⁶ 2824888

Matrices. According to the method according to the invention the sleeves pulled to a desired depth, creating an outwardly widened hand around their opening, which can then be removed before the finished sleeve is ejected.

In the process according to the invention, the metal experiences No work hardening in the edge area of the sleeve, so that the risk of cracking or splintering is reduced is. When using the method according to the invention, the upper edge of the sleeve can in a final Operation can be removed on one and the same device, so it does not need to be in one to be turned off or cut off in some other way.

In the method according to the invention, the sleeve experiences only an extremely low work hardening so that it remains relatively soft and for further processing suitable is.

The invention thus creates a method which consists of several in a predetermined relationship to one another Steps is constructed, as well as a device for performing the various method steps.

In particular, the invention provides a method for producing cup-shaped, cylindrical sleeves with a thickened base and thin wall areas, in which a cup-shaped blank is inserted into a die is used, the bottom of which is at least partially formed by a peg, whereupon a punch in the The blank is introduced and a pressure is applied to the edges of the blank by means of a bushing surrounding the punch is exerted to extrude its material so that there is the cavity between the punch and the bottom

909882/0778

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and the side walls of the die are completely filled. In a second step, the cylindrical peripheral wall using a second die without changing the thickness of the base to the desired wall thickness pulled, whereupon an outwardly protruding upper edge formed during pulling is removed by shearing off can be.

In the following an embodiment of the invention is explained with reference to the drawing. Show it:

Fig. 1 is a partially sectioned side view of the lower part of a cup-shaped Blank for the production of a sleeve,

FIG. 2 shows a sectional view of a known method arrangement with several arranged one above the other Matrices and a sleeve pressed through them by means of a punch,

Fig. 5 is a partially sectioned side view the sleeve formed in the known method according to Fig. when cutting it to length,

4 shows a sectional view of a die arrangement according to the invention with a die introducing the blank into a closed die for shaping the bottom of the sleeve to precisely predetermined values Dimensions and shape,

Fig. 5 is a sectional view of a second die assembly with a finished sleeve,

6 is a sectional view of an arrangement for removing the upper edge of the drawn sleeve;

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7 is a schematic Figv -. _R side view partially in section of the drive means for a punch and a corresponding Bruekbuchse for executing the process steps shown in Fig, 4, and

Fig. 8 is a partially sectioned side view a modified embodiment, at which the pressure socket is made in one piece with the stamp.

Fig. 1 of the drawing shows a blank 10 of a conventional type Amount of material in the bottom 11 of the blank can be calculated extremely precisely so that the finished sleeve has a bottom whose dimensions are within acceptable tolerances ..

Fig. 2 shows an arrangement of stacked: dies of decreasing diameter ^ through which the blank is pressed by means of a tapered punch, the dies 12 deform the material at the bottom of the blank both radially and axially to the dimensions indicated by 11 ' and stretch the peripheral wall 14 to reduce its diameter. In the known method, the semi-finished blank is then placed on another, almost cylindrical, punch and pressed by this through a second arrangement of matrices stacked on top of one another, the bottom 11 ″ being given the shape shown in FIG 14- ^{r is drawn} to a wall thickness that tapers to a lesser extent.The sleeve, which has been completed so far, has an irregularly shaped upper edge, which then has to be removed by means of a cutting tool 15 or the like.

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In the case of the one described above formed sleeve, the metal is work-hardened in all areas through the repeated drawing process, so that a soft annealing is necessary before further processing. The sleeve is always complete pressed through the matrices stacked on top of each other and must then be removed from the respective punch removed and transferred to a subsequent arrangement.

In the method according to the invention, a blank essentially corresponding to the blank 10 is placed in a die. 21, the cavity of which has a cylindrical area 22 and a frustoconical area 23, while its bottom 24 is formed by the slightly concave upper end of a peg 25. A punch 26 is inserted so far into the die that the space present between it and the walls 23, 24- of the cavity corresponds exactly to the amount of material required for the bottom of the sleeve and the shape of the bottom. A bushing 27 guided slidingly on the punch is guided downward under pressure onto the upper edge of the blank in order to compress its material so that it flows into the space delimited by the punch and the walls of the cavity and completely fills it.

The partially formed sleeve 29 is then transferred to a second die 31 and by means of a Stamp, the outer shape and dimensions of the Corresponds to the inner shape or the inner dimensions of the finished sleeve, pressed through the die 31. The die 31 is slightly widened below its working area 32 and above it rounded outwards, so that at the upper end of the sleeve an outwardly curved edge 53 is disfigured »

Depending on the dimensions desired for the finished sleeve Its cylindrical part may require several operations of the type described above. In this case, however, the sleeve is never pressed completely through a die, so that its edge 33 does not experience any strain hardening.

The extent completely shaped sleeve is then set to a Abscherstempel 35 and the edge 33 of the die is sheared by this forced through a die 36 _T between an edge 37 of the punch and an edge 38th This operation is the only one in which the sleeve is pressed completely through the die.

The operations described above can be performed on a multi-punch press be carried out, e.g. by means of a suitably modified Waterbury Farrel Cam Eyelet machine. In Fig. 7 one recognizes a ram 4-0 carrying the punch 26, a die 21 and a Jack 25 corresponding to the arrangement according to FIG. 4. The bushing 27 is shown as the lower end piece of a sliding sleeve 41, which under suitable Synchronization with the ram and the ram actuating cams via a rocker arm 42 from one Cam 43 is actuatable. In a preferred work sequence the sleeve or the blank is inserted into the die, the pressure bushing is in contact with the upper one Bringing the edge of the blank and the punch is inserted into the blank to hold it against the inner wall 23 of the To press die. The bush 27 is then moved further downward relative to the punch in order to insert the metal into the to press the space delimited by the punch, the pusher and the inner walls of the die.

$ 909882/077

Requires a blank to be used for the first die not, as is the case with the conventional method, to have "exact dimensions" since the sleeves The bottom is precisely shaped in a bar that is closed on all sides will*

The independently movable Bruck bushing described above enables adaptation to various Modifications of the procedure and therefore deserves preference. When using Kohlingen of more uniform However, sizes are comparable to the results in Fig. 8 achievable arrangement in which a Bruckbuehse 50 test connected to a stamp 5T and can be introduced into a matrix 52 together with the latter is to the MateriaT of the Eohling as well as in the Arrangement according to FIG. 4 to. a precisely defined form to press. The Eohling formed in this way will be then in the same way as above anftandv vöh. FIGS. 5 and 6 describe the final shape of the sleeve pulled and sheared "

All of the Bes & hreibung _r claims and the drawing features and advantages of the dung OF INVENTION ",, including design details" spatial arrangements and process steps, can be erfindunprswesentlieh both alone aucPi in any combination.

Claims (2)

Attorney file 30 172 M / process, for forming cup-shaped sleeves, characterized in that one has a closed die, two open dies and = three each one of the dies assigned punch is used, the bottom of the first punch together with the bottom wall of the closed die one of the desired shape and dimensions of the Limit the corresponding cavity at the bottom of the finished sleeve, the second punch of the desired inner shape has the shape and dimensions of the finished sleeve plus an enlarged upper end piece, the first open die has the desired outer diameter the finished sleeve plus a smooth rounded extension at the upper end Has diameter, the third punch has a tapering insertable into the upper end piece of the sleeve lower part and this upwardly limiting, annular step with an outer diameter of the Sleeve has substantially the same diameter and the second open die at the upper end one 909882/0778 has narrowed annular area, the diameter of which corresponds essentially to that of the annular step, that a cup-shaped blank is inserted into the closed die, that the first punch in, a Position is moved in which he, together with the bottom wall of the die, one of the Porm and the dimensions delimits the bottom of the finished sleeve corresponding cavity into which the material of the blank is extruded that the blank is transferred to the first open die, that the second punch is actuated, around the peripheral wall of the blank to the desired inside and outside diameter plus one outward curly upper edge to pull that the blank is transferred to the second open die, and that the third punch is actuated to shear off the curved upper edge of the blank from this. 2. The method according to claim 1, characterized in that an element associated with the stamp is moved towards the blank in order to extrude the material thereof. 3- The method according to claim 2, characterized in that the element surrounds the stamp Socket is. ■ · 909882/0778