EP1712307A2 - Method of producing a sheet metal part with at least one at least partially rolled edge and product obtained by this method. - Google Patents

Abstract

Production of a workpiece (10) in the form of a sheet (12) with at least one partially rolled edge (14) where the edge to be rolled has a section (16) with a bend involving:preparation of the workpiece with the partially rolled section, and a material extension (17) in the longitudinal direction over part of the edge to be rolled, so that the edge to be rolled in the material extension region projects transverse to the longitudinal direction of edge (14) and the flash of the material projection is then rolled. An independent claim is included for a workpiece in the form of a sheet.

Description

The invention relates to a method for producing a workpiece in the form of a sheet with at least one at least partially rolled edge, wherein the at least one edge to be rolled has a curvature in at least one section, with the steps of providing the workpiece and at least partially rolling the at least one edge of the workpiece.

The invention further relates to a workpiece produced by the above-mentioned method in the form of a sheet with at least one at least partially rolled edge.

A method of the type mentioned is, for example GB-A-403 594 well known.

It is known to roll edges of sheets, for example, to obtain a reinforced edge of the sheet, or to produce, for example, a hinge eye on the sheet.

For rolling an edge of the workpiece in the form of a sheet, the workpiece is placed in a special rolling tool, which has a tool upper part and a lower tool part. The upper tool part and the lower tool part are movable relative to one another. In one of the two tool parts a part-circular in cross-section trough is present, in which the workpiece is pressed with the edge to be rolled forward by the relative movement between the lower part of the tool and the upper part of the tool. As the edge pushes into the part-circular trough, the edge curls along the inner wall of the part-circular trough. Rolling of the edge may, for example, be done only partially, for example over a roll angle of 90 ° to 180 °, or over 180 °, until a roll angle of nearly 360 °, i. a complete curl of the edge is achieved.

In the above document GB-A-403 594 a method for rolling edges of sheets is described. There, the technical problem is described that a rolled by about 360 ° edge in a subsequent bending of the sheet either further rolls in or unrolls. To avoid this problem of further curling or unrolling during bending of the sheet after rolling, it is proposed there to roll the edge by more than 360 ° so that the curled edge has at least a region of a double material layer.

On the other hand, the technical problem underlying the present invention is another which arises when the edge to be rolled, i. before its rolling, has a curvature or bend.

Namely, not only those workpieces whose rolling edge is straight can be rolled, but also those whose rolling edge has a curvature in at least one section, which also includes the case that the edge to be rolled over its entire length to be rolled Has curvature or bending.

For sheet edges that have such a curvature, it has been found that when rolling the edge in the curvature of an undesirable kink arises, ie after rolling the edge, the workpiece in the curvature of the curvature in the edge has a kink on the usability of the workpiece for its later purpose, for example, as a component in the automotive industry, reduced or even completely excludes. Such a kink can affect not only the aesthetic appearance of the tool thus produced, but also its strength or stability, since the resulting kink can continue buckling under load or stress of the workpiece.

The invention is therefore based on the object to improve a method of the type mentioned in that when rolling the edge of the workpiece, the risk that a kink in the rolled edge is formed, avoided or at least reduced.

According to the invention, this object is achieved with respect to the method mentioned above in that the workpiece is provided in the at least one section which has the curvature, with at least one material extension extending in the longitudinal direction of the edge over a partial region of the at least one edge to be rolled so that the edge to be rolled protrudes in the area of the material extension over the edge adjoining the material extension transversely to the longitudinal direction of the edge, and that the edge, including that of the material extension, is subsequently rolled.

It has been found that when rolling the risk of kinking in the edge in the region of the curvature can be avoided or at least reduced if the workpiece in the region of curvature of the edge has additional material in the form of the aforementioned material extension, which in the rolling process together with the remaining edge is rolled up with. The extent to which the material extension protrudes beyond the edge adjacent to the material extension transversely to the longitudinal direction of the edge, is expediently chosen so that the material extension does not or does not substantially reduce the roll angle to be achieved. This is not a problem when a roll angle of about 180 ° is selected, that is, the rolling edge is rolled about 180 °, as in this case for the material extension still sufficient space within the rolled edge is available. The inventively provided material extension preferably extends in the longitudinal direction of the edge to be rolled over a portion of the edge to be rolled, which corresponds approximately to the length of the portion of the edge in which the curvature is present.

According to a preferred embodiment, the at least one material extension extends beyond the smallest radius of the curvature.

This measure is particularly advantageous if the edge to be rolled has a curvature whose radius of curvature is not constant over the curvature, but rather changes. This may for example be the case when the workpiece has a straight portion and a curved portion, wherein the curved portion merges into the straight portion. From the transition of the straight section into the curved section, the radius of curvature initially decreases continuously until a region of the smallest radius of curvature is reached. In such a constellation, the at least one material extension is preferably arranged in the region of the smallest radius of curvature and preferably extends over the smallest radius of the curvature.

In a further preferred embodiment, the edge of the at least one material extension passes smoothly over into the edge adjoining the material extension.

This measure has the advantage that in the transition region from the edge of the material extension into the material extension adjacent edge or edge notch effects or cracking when rolling the edge can be avoided.

In this context, it is further preferred if the edge of the at least one material extension transitions obliquely straight or in a convex or concave line into the edge adjoining the material extension.

The aforementioned embodiments represent advantageous examples of a smooth transition of the edge of the material extension into the edge adjoining the material extension.

In a further preferred embodiment, the material extension is formed integrally with the remaining material of the workpiece.

This measure has the advantage that the production cost of the workpiece compared to the conventional method, in which no material extension, as described above, is provided is not increased because in a one-piece design of the material extension this already in the prefabrication of the workpiece to be rolled with can be taken into account, ie does not have to be added as an additional component to the workpiece.

In this context, it is preferably provided to provide the workpiece together with the material extension as a one-piece stamped part.

This represents a manufacturing technology particularly simple and thus advantageous cost option, the material extension integrally formed with the remaining material of the workpiece.

An inventively produced according to one or more of the aforementioned embodiments workpiece in the form of a sheet having at least one at least partially rolled edge has the advantage that it is kink-free in the region of curvature or in the region of the curvatures of the edge or a possible kink less pronounced is than with the conventionally produced workpieces.

Further advantages and features will become apparent from the following description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Fig. 1a)-1f)

ein Verfahren zum Herstellen eines Werkstückes in Form eines Bleches mit einer teilweise gerollten Kante in drei schematisch dargestellten Verfahrensstufen, wobei Fig. 1a) das Werkstück in Seitenansicht in einer ersten Verfahrensstufe und Fig. 1b) das Werkstück zusammen mit dem Werkzeug in einer Stirnansicht zeigt, Fig. 1c) und 1d) das Werkstück in Seitenansicht bzw. das Werkstück und das Werkzeug in Stirnansicht in einer zweiten Verfahrensstufe und Fig. 1e) und 1f) das Werkstück in Seitenansicht und das Werkzeug in Stirnansicht in einer dritten Verfahrensstufe zeigen; wobei Fig.1 den Stand der Technik darstellt; und

Fig. 2a)-2f)

den Fig. 1) bis 1f) entsprechende Darstellungen eines Verfahrens zum Herstellen eines Werkstücks in Form eines Blechs mit einer zumindest teilweise gerollten Kante gemäß der vorliegenden Erfindung.

An embodiment of the invention is illustrated in the drawing and will be described in more detail with respect to hereafter. Show it:

Fig. 1a) -1f)

a method for producing a workpiece in the form of a sheet with a partially rolled edge in three schematically illustrated process steps, wherein Fig. 1a) shows the workpiece in a side view in a first process stage and Fig. 1b) shows the workpiece together with the tool in an end view, Fig. 1c) and 1d) the workpiece in side view and the workpiece and the tool in front view in a second process stage and Fig. 1e) and 1f) show the workpiece in side view and the tool in front view in a third process stage; wherein Fig.1 represents the prior art; and

Fig. 2a) -2f)

1) to 1f) corresponding representations of a method for producing a workpiece in the form of a sheet with an at least partially rolled edge according to the present invention.

First, with reference to Fig. 1, a method for manufacturing a workpiece in the form of a sheet with an at least partially rolled edge according to the prior art will be described.

In Fig. 1a) a provided with the general reference numeral 100 workpiece is shown, which is provided in the form of a sheet 102. The sheet 102 has an edge 104 which is to be rolled. Rollers is a forming operation in the context of non-cutting production, in which a sheet metal edge is generally bent so that the bent edge seen in cross section occupies a substantially part-circular shape. However, the shape of the bent edge does not have to have a circular shape, but may also have a different shape in cross section.

The workpiece 102 according to FIG. 1 a) has a section 106 in which the workpiece 102 and in particular the edge 104 has a curvature.

According to FIG. 1 b), the sheet 102 is brought into a rolling tool 108, which has a tool upper part 110 and a tool lower part 112. The tool upper part 110 can be moved toward the tool lower part 112 in accordance with an arrow 114.

Of course, it can also be provided that the tool upper part 110 is stationary, and the tool lower part 112 is movable against the direction of the arrow 114 toward the tool upper part 110.

In the tool top 110 there is a semicircular trough or cavity 116 which serves to roll the edge 104. Usually, the edge 104 to be rolled, contrary to the illustration in FIG. 1b), is slightly tilted before rolling.

In the lower tool part 112, the sheet 102 is firmly clamped.

In Fig. 1c) and 1d), a second stage of the rolling process is shown. The edge 104 has now been rolled by pressing the sheet 102 with the edge 104 to be rolled into the tool upper part 110 in front by approximately 90 °. Fig. 1c) shows the sheet 102 in side view in this intermediate stage of the rolling process.

Fig. 1e) and 1f) now show the third stage of the rolling process, in which the edge 104 has been rolled by about 180 °. In Fig. 1e) it is shown that the further rolling of the edge 104 starting from Fig. 1c) to Fig. 1e) in the portion 106 in which the sheet 102 has the curvature, an undesirable kink 116 has formed, the usability the workpiece 102 is reduced or even completely eliminated for its further processing or its later intended use. With the conventional method, it is not guaranteed to roll a curved edge of a workpiece kink-free.

With reference to Fig. 2, a method according to the invention will now be described which remedies the problem of buckling previously described with reference to Fig. 1.

Fig. 2a) shows a workpiece 10 in the form of a sheet 12 having an edge 14 which is to be at least partially rolled. The shape of the workpiece 12 corresponds to the shape of the workpiece 102 in Fig. 1a), and this has a corresponding section 16, in which the workpiece 12, but in particular the edge 14 has a curvature.

In contrast to the sheet 102 in Fig. 1a), the sheet 12 is now provided so that in the portion 16 having the curvature, a material extension 17 is present, extending in the longitudinal direction of the edge 14 (x-direction) over a Part of the rolling edge 14 extends. In the region of the material extension 17, the edge 14a protrudes beyond the edge 14b or 14c adjoining the material extension 17 transversely to the longitudinal direction of the edge 14, ie in the y-direction. The material extension 17 extends over a point 19 of the smallest radius of the Curvature of the portion 16 on both sides of the point 19 away. In this case, the edge 14a of the material extension 17 merges smoothly into the edge 14b or 14c adjoining the material extension 17, specifically in the embodiment shown with a respective oblique straight line 21 or 23. Instead of a straight transition between the edge 14a and the edge 14c or 14b, however, a curved, for example convexly curved or concavely curved transition can be selected.

The material extension 17 is in particular integrally formed with the remaining material of the workpiece 10 and the sheet 12. The workpiece 10 is preferably punched together with the material extension 17 previously in a punching process from a flat product, the punching tool (not shown) correspondingly has a shape that is cut out during punching of the material extension 17 together with the remaining part of the sheet 12 from the flat product ,

2 b) shows, corresponding to FIG. 1 b), a rolling tool 18 with a tool upper part 20 and a tool lower part 22, the tool upper part 20 being movable on the tool lower part 22 according to an arrow 24 or the tool Lower part 22 opposite to the arrow 24 to the tool upper part 20 is movable.

In the tool lower part 22, the sheet 12 is clamped.

In the tool upper part 20, a trough 26 is formed, which corresponds to the trough 116 of the tool upper part 110 in Fig. 1. At this point it should be noted that both the trough 116 and the trough 26 in the longitudinal direction of the edge 104 and the Edge 14 or perpendicular to the plane in Fig. 1b) and Fig. 2b) corresponds to the curve or line shape of the edge 104 and the edge 14.

If, according to FIG. 2d), the sheet 12 is pressed into the depression 26 by the relative movement between the tool upper part 20 and the tool lower part 22, initially only the material extension 17 or its edge 14a with the depression 26 of the tool shell comes 20 engaged and is rolled. The remaining edge 14 of the sheet 12, however, remains initially out of engagement with the tool shell 20. In Fig. 2c), the workpiece 10 is shown in this intermediate stage of the rolling process, in which only the material extension 27 partially (according to Fig. 2d) via a roll angle of about 90 °) is rolled while the remaining edge 14 of the sheet 12 is not rolled yet.

When rolling further according to FIG. 2f), the remaining edge 14 now comes into engagement with the trough 26 of the tool upper part and is rolled, as shown in FIG. 2f) over a roll angle of approximately 180 °. In this case, the material extension 17 according to FIG. 2f) was rolled further, specifically by about 270 °. As shown in Fig. 2e), now arises in contrast to the method of FIG. 1 in the edge 14 of the sheet 12 when rolling in the section 16 no kink. The material extension 17 has avoided the formation of a kink, but at least reduced the risk of such kinking.

It is understood that in the context of the invention, a curvature can be present not only in one plane but also in two or three planes.

In particular, the workpiece 10 made with a rolled edge may be a backrest portion of a motor vehicle seat having a curvature such as shown in FIG. With the method according to the invention for producing the workpiece 10 with a rolled edge 14, a workpiece 10 suitable for further use and processing or processing is obtained for such a backrest part, which is difficult or impossible to produce with the conventional method.

Claims (7)

A method of manufacturing a workpiece (10) in the form of a sheet (12) having at least one at least partially rolled edge (14), the at least one rolled edge (14) having a bend in at least one portion (16), with the steps Providing the workpiece (10) and at least partially rolling the at least one edge (14) of the workpiece (10), characterized in that the workpiece (10) in the at least one section (16) having the curvature with at least one in the longitudinal direction of the edge (14) over a partial region of the at least one edge (14) to be rolled material extension (17) is provided, so that the rolling edge (14a) in the region of the material extension (17) on the material extension (17 ) adjacent edge (14b, 14c) projects transversely to the longitudinal direction of the edge (14), and that the edge (14) including that of the material extension (17) is subsequently rolled. A method according to claim 1, characterized in that the at least one material extension (17) extends over the smallest radius of curvature away. Method according to claim 1 or 2, characterized in that the edge (14a) of the at least one material extension (17) merges smoothly into the edge (14b, 14c) adjoining the material extension (17). A method according to claim 3, characterized in that the edge (14a) of the at least one material extension (17) transitions obliquely straight or in a convex or concave line into the material extension (17) adjacent edge (14b, 14c). Method according to one of claims 1 to 4, characterized in that the material extension (17) is formed integrally with the remaining material of the workpiece (10). A method according to claim 5, characterized in that the workpiece (10) is provided together with the material extension (17) as a one-piece stamped part. Workpiece in the form of a sheet (12) with at least one at least partially rolled edge (14), produced by a method according to one of claims 1 to 6.

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