Method for producing press-hardened door ring and at least one further press-hardened component for motor vehicle

Abstract

The invention relates to a method for producing a press-hardened door ring (210) and at least one further press-hardened component (220) for a motor vehicle, comprising: providing a forming blank having a first region with a door opening cut-out and a second region from which the door ring (210) is formed, forming a further component (220) from the second region, the second region being arranged within the door opening cutout; heating the shaped blank; the heated forming blank is introduced into a press-hardening tool, and a press-hardening process is carried out, in which both the door ring (210) and the further component (220) are shaped into the respectively set final geometry and hardened, and wherein a separate cut is also carried out in the press-hardening tool, said separate cut severing the door ring (210) and the further component (220).

Description

Technical Field

[0001] The present invention relates to a method for producing a press-hardened ( A method of forming a press-hardened (or die-hardened) door ring and at least one further press-hardened component. Background Art

[0002] In so-called press hardening, the steel sheet material suitable for press hardening is heated to the austenitizing temperature and pressed in a cooled tool (press hardening tool ( Sometimes referred to as press hardening, the process involves forming (geformt) in a die and cooling simultaneously, wherein the hardness or strength increases due to the martensitic hardening effect (hardness and strength are typically correlated). Press hardening itself is known from the prior art, for which reference is made below to the corresponding patents and technical literature.

[0003] A so-called door ring is a side wall body component which completely surrounds at least one door opening, namely the front door opening and / or the rear door opening. Such a door ring can be assembled from a plurality of sheet metal molded parts. In addition, such a door ring can also be produced as a one-piece sheet metal molded part, which is accompanied by many advantages, such as, for example, the elimination of tolerance-sensitive joining steps, reduced production time, reduced weight (by eliminating the joining flange) and improved dimensional stability.

[0004] DE 112017003027 T5 describes a method for producing a door ring comprising a plurality of columns and beams surrounding at least one door opening. The method first comprises providing a door ring blank, which defines at least one door opening section. The door ring blank further comprises at least one reinforcement section, which extends through the at least one door opening section. The method continues by heating the door ring blank and arranging the heated door ring blank in a punching die. The method then continues by hot punching the door ring blank in the die to construct the door ring and the at least one reinforcement. During the hot punching step, the at least one reinforcement is in the free space between the column and beam sections of the door ring blank. After the hot punching step, the method continues by removing the punched door ring and reinforcement from the punching die and transferring the constructed component to a separate station for removing the at least one reinforcement from the door ring, for example by laser or cutting. After removing the at least one punched reinforcement, the method continues by placing the at least one reinforcement at the door ring at a desired location.

[0005] Therefore, in the method previously known from DE 112017003027 T5, the door cutout ( Sometimes referred to as door blanking or door cutouts) in the area of ​​the joint molding reinforcement. As explained in DE 112017003027T5, this is accompanied by many advantages. In addition, but also improve or increase material utilization. Summary of the invention

[0006] Starting from the prior art explained above, the object of the present invention is to specify an improved and, in particular, economically optimized method for producing a press-hardened door ring and at least one further press-hardened component.

[0007] This object is achieved by the method according to the invention according to patent claim 1. Advantageous developments and embodiments of the invention are apparent from the dependent patent claims, the following description of the invention (which explicitly also includes the features described by way of example and optionally) and the figures.

[0008] The method according to the invention for producing (ie for co-producing) a press-hardened door ring for a motor vehicle and at least one further press-hardened component for a motor vehicle comprises at least the following steps:

[0009] - Providing a form blank (Formplatine, sometimes called a form plate blank) having a door opening cutout ( a first region (sometimes referred to as a door opening blank or door opening cutout) from which the door ring is formed and a second region from which (at least one) further component is formed, wherein the second region is arranged within the door opening cutout;

[0010] - Heating the shaped blank;

[0011] - The heated shaped blank is placed in a press-hardening tool and a press-hardening process is carried out, in which not only the door ring but also the (at least one) other component is modified (umformen, sometimes called deformed or formed) into its respectively set final geometry (so that no further modification is performed thereafter) and is also hardened or press-hardened, wherein separate cuts for cutting off the door ring and the other components are also carried out or introduced in the press-hardening tool.

[0012] The door ring thus produced and the further component produced almost simultaneously (hereinafter referred to as at least one further component) can be removed from the press-hardening tool as separate components and can be processed further immediately and independently of one another. Therefore, a station specially provided for separating the components is no longer necessary. This reduces production time and equipment costs. In addition, however, energy savings are also achieved. The method according to the invention is therefore particularly economical and has many further advantages.

[0013] According to the invention, the door ring and the further component are manufactured almost simultaneously from the same blank (molded blank; see below). The door ring is a one-piece (i.e. manufactured in a single piece) press-hardened sheet metal molded part, which has at least one door opening which is completely surrounded or closed around, the door opening being in particular a front door opening. The door ring can also have two door openings which are completely surrounded or closed around (front door opening and rear door opening) (double door ring). The further component is likewise a one-piece press-hardened sheet metal molded part, which is in particular a body or running gear component (Fahrwerksbauteil, sometimes referred to as a chassis component). However, the further component can also be a supplementary component for the door ring.

[0014] The blank is a so-called profiled blank, which is constructed in one piece and has a contour geometry (Umrissgeometrie, sometimes referred to as contour geometry) determined by the component or sheet metal profile to be manufactured (see below). The profiled blank is formed from a steel sheet material suitable for press hardening (e.g. 22MnB5 or CR1500), which may also have an oxide scale and / or a corrosion protection coating (e.g. AlSi or Zn coating). The profiled blank is preferably constructed flat. The profiled blank is preferably constructed in an integral manner (monolithisch, sometimes referred to as a single piece) (i.e., it consists of a single sheet metal part without joints) and in particular also has a uniform or uniform sheet metal quality and sheet metal thickness. (Sheet metal quality refers in particular to the mechanical properties of the steel sheet metal material, such as, for example, strength and strain characteristics). Therefore, the door ring and other components are not only one-piece but also integral sheet metal profiles. Therefore, the disadvantages associated with welded blanks (Tailored Welded Blanks, sometimes referred to as Tailored Welded Blanks or TWBs) do not occur in the present invention.

[0015] The profiled blank can also have different sheet thicknesses in some areas, so that the door ring and / or other components produced therefrom can have corresponding areas with different sheet thicknesses, which can achieve particularly advantageous matching to locally different strength and / or crash requirements on the one hand and weight optimization on the other hand. Such profiled blanks can be formed by so-called flexible rolling. Flexible rolling and flexible rolled sheet materials are known from the prior art, for example, reference is made to DE 10 2012 110 972 B3 (and to the prior art mentioned elsewhere therein). The blanks or profiled blanks produced by flexible rolling can also be referred to as tailor-made rolled blanks (TRB).

[0016] The molded blank has a first region from which the door ring is molded or produced, wherein the first region comprises at least one door opening cutout corresponding to a completely enclosed door opening of the door ring. In other words, the door opening cutout is provided for forming a completely enclosed or encircling closed door opening of the door ring and is therefore also designed to completely enclose or be closed in itself. Preferably, the perimeter geometry of the first region (i.e. the outer perimeter and also the inner perimeter of the door opening cutout) corresponds at least approximately to the perimeter geometry of the flat extension of the door ring to be produced.

[0017] The shaped blank furthermore has a second region from which the further component is shaped or produced, wherein the second region is arranged completely within the door opening cutout (of the first region) or is located within the door opening cutout. Preferably, the circumferential geometry of the second region corresponds at least approximately to the circumferential geometry of the flat extension of the further component to be produced.

[0018] The first region and the second region of the profile blank are connected to one another. Preferably, the profile blank has a plurality of connecting webs or the like connecting the first region and the second region, wherein in particular at least three, at least four or at least five connecting webs are provided.

[0019] Preferably, the shaped blank is produced in a preceding manufacturing or production step by cutting out from a sheet metal semi-finished product, such as a sheet metal block or sheet metal strip, in particular a flexibly rolled sheet metal semi-finished product. The cutting out can be carried out by mechanical cutting, for example in a cutting or forging press with a correspondingly configured tool, or by means of a laser, for example in a laser cutting station.

[0020] First, the forming blank is heated, which means heating to the austenitizing temperature, which can be carried out in a furnace, for example. The heated and not yet deformed or flat blank is then placed in a press hardening tool, where it is then reshaped (hot reshaped) and hardened within the scope of the press hardening process. This preferred approach is also called direct press hardening. However, the present invention can also be applied to indirect press hardening, in which pre-forming of the blank is first carried out. Preferably, the method according to the invention is implemented in such a way that not only the door ring but also other components are completely press hardened and therefore have a basically martensitic structure. However, the method according to the invention can also be implemented in such a way that different material structures or organizational components are produced by locally different heating (of the forming blank) and / or by locally different cooling in the press hardening tool and / or by other measures, so that different mechanical property values ​​(especially strength and strain property values) appear in partial areas in the manufactured door ring and / or other components. The method according to the invention can also be implemented in such a way that only partial or one-sided (sometimes referred to as local) press hardening takes place, in particular with the aim that the manufactured door ring and / or another component has at least one partial region which is designed to be soft and ductile (so-called soft region). In particular, it is provided that the strength or hardness in such a soft region corresponds to the original strength or hardness of the steel sheet material of the profile blank, i.e. no hardening or press hardening takes place. This can be achieved, for example, by heating the press hardening tool in the relevant tool region.

[0021] According to the invention, a separating cut is also carried out in the press hardening tool, i.e. a separating operation is performed, whereby the door ring and the further component are separated from one another and thus separated. The separating cut can include a plurality of separation locations, in particular all the connecting tabs (see above), wherein the connecting tabs are preferably cut off in such a way that they remain on the door ring or the further component and can then possibly also be cut off in a later contour cutting operation. Furthermore, it can be provided that the connecting tabs are cut off or cut off not only on the door ring but also on the further component and then removed from the press hardening tool as waste parts via a fall well or the like. The separating cut is preferably carried out before the sheet material (steel sheet material) has completely cooled at the at least one separation location or at the plurality of separation locations, or as long as the sheet material (at the at least one separation location) is still hot and in particular still has a temperature of 100° C. to 200° C., so that the strength is lower than in the cooled state. This can be achieved, for example, by the hot press hardening tool not being cooled or even (actively) being heated locally in the region of the at least one separating point or the separating web.

[0022] The separating cut can be carried out after the door ring and the further components have been reshaped. However, the separating cut can also be carried out before the door ring and / or the further components have been reshaped or completely formed, which means in particular that the separating cut is carried out during the reshaping process, preferably at the end of the reshaping process, in particular when more than 90% and less than 100% of the reshaping has been achieved. This can be used to influence the further or remaining reshaping processes in a targeted manner, for example by promoting the material flow at specific locations through the separating process. It is then preferably also provided that, after the introduction or implementation of the separating cut, at least the further components are fixed in the press-hardening tool in order to prevent slippage during the further reshaping. This can be achieved, for example, by means of a spring-loaded clamping device, for example in the form of a die or the like.

[0023] It is furthermore preferably provided that contour cutting, in particular outer contour cutting, of the door ring and / or another component is also carried out or implemented in the press hardening tool, wherein contour cutting (inner contour cutting) of the at least one door opening at the door ring can also be provided. Likewise, perforation (for producing a hole) can also be carried out in the press hardening tool. This is carried out in particular with the aim that no further cutting operations are required at the door ring or another component after removal from the press hardening tool. Contour cutting and / or perforation can be carried out before the sheet material has completely cooled down at the cutting line or perforation line, or as long as the sheet material (at the cutting line or perforation line) is still hot and in particular still has a temperature of 100° C. to 200° C., analogously to the previous explanations. This can also be referred to as hot cutting or hot perforation.

[0024] The press-hardening tool for carrying out the method according to the invention has at least one first cutting device, with which the separating cuts are carried out. The press-hardening tool can optionally have a second cutting device, with which the contour cutting and / or the opening are carried out. The cutting devices of the press-hardening tool can each include at least one conventional cutting blade and an associated cutting die. Preferably, the press-hardening tool has a tool bottom part and a tool top part that can be moved relative to it and is installed in a press. The cutting device can be controlled by means of a gas pressure spring depending on the closing stroke.

[0025] It is preferably provided that during the shaping of the (steel sheet material) in the press hardening tool, the separation point or the plurality of separation points (at which the separation cuts are made) are oriented in such a way that the steel sheet material is oriented perpendicularly or substantially perpendicularly (i.e., for example, 90°+ / -10°) to the tool closing direction (of the press hardening tool) at the separation point, which refers to the local surface orientation of the steel sheet material at the separation point. This also applies in particular if the connection between the first region and the second region (of the profiled blank), in particular the connecting web, is at least partially jointly shaped during shaping. The perpendicular orientation enables a relatively simple design of the first cutting device without a slide and promotes a long service life of the cutting device and an optimal cutting result.

[0026] Alternatively, as described in DE 112017003027 T5, the door ring and / or another component can be locally reinforced by at least one reinforcement element. Such a reinforcement element can be applied to the molded blank before press hardening or can also be applied to the press hardened door ring or the press hardened other component after press hardening and fixed in a materially bonded manner. This is also called "repairing".

[0027] Within the scope of the invention, not only the features described above but also the features explained below can be used not only in the respectively specified feature combination but also in other feature combinations or alone. This also applies to the features shown in the figures (see below). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention is explained in more detail below with reference to schematic (not to scale) drawings. The features shown in the drawings and / or explained below can also be general features of the invention independently of a specific feature combination and improve the invention accordingly.

[0029] Figure 1 Shown are shaped blanks for producing press-hardened door rings and other press-hardened components according to the invention.

[0030] Figure 2 Shown by Figure 1 Door knockers and other components are manufactured from shaped blanks. DETAILED DESCRIPTION

[0031] Made of steel plate material S Figure 1 The flat shaped blank 100 shown in FIG. 1 is constructed in one piece and in one piece and is constructed with a uniform sheet thickness (eg 1.7 mm) and a uniform sheet quality. The shaped blank 100 has a first region 110 from which the Figure 22. The door ring 210 is a crash-relevant structural component of the vehicle body, which is not visible in the installed state. The door ring 210 has a front door opening 215 which is completely surrounded or closed all around. The first region 110 of the molded blank 100 has a (front) door opening cutout 115 corresponding to the front door opening 215 at the door ring 210, which is illustrated by means of the dot-dash line of the perimeter. The door opening cutout 115 is almost completely surrounded or enclosed by the first region 110. The molded blank 100 also has a second region 120, which is shown with hatching, from which the door opening is generated. Figure 2 2. The second region 120 is arranged in the door opening cutout 115 and is connected to the first region 110 by means of a plurality of connecting webs 130. The profile blank 100 has a contour geometry that is matched to the component or sheet metal profile 210, 220 to be produced.

[0032] In order to produce the components 210, 220, the provided shaped blank 100 is first heated and placed in the heated state into a press hardening tool. A press hardening process is then carried out in the press hardening tool, in which press hardening process both the door ring 210 and the further component 220 are almost simultaneously (i.e. typically within one press stroke) transformed into their correspondingly provided final geometry and hardened or press hardened. Due to the relative position of the two components 210, 220, simultaneous production can also be referred to as piece-in-piece production. A separating cut is then also carried out in the press hardening tool, in which the connecting tab 130 is cut or cut open, thereby separating or separating the door ring 210 and the further component 220.

[0033] Figure 2 The press-hardened door ring 210 and the further press-hardened component 220 are shown in their tool position after press hardening. (The cut or cut connecting tab 130 is not shown). Both the door ring 210 and the further component 220 are of one-piece and integral design and have approximately the same sheet thickness as the profiled blank 100 (e.g. 1.7 mm). The two separate components 210, 220 can be easily removed from the press-hardening tool. This can be done with the aid of a gripper, which holds the two components 210, 220 separately. It is also possible to produce a plurality of further components simultaneously in the manner explained above, instead of just one further component 220.

[0034] The door ring 210 also has a rear door opening 217 that is not completely surrounded, wherein the molded blank 100 is constructed with a corresponding (rear) door opening cutout 117 that is not completely surrounded. Similar to the above explanation, this door opening cutout 117 can also be used to produce at least one other press-hardened component. The rear door opening 217 can also be completely surrounded or closed around (double-door-ring). In this case, at least one other component 220 can be produced together not only in the corresponding front door opening cutout but also in the corresponding rear door opening cutout.

[0035] The one-piece and integrally constructed door ring 210 can also have at least one soft region W in which the sheet steel material S is soft and ductile, at least softer and more ductile than in adjacent regions. In the illustrated embodiment, the soft region W is in the transition between the B-pillar and the door sill and simultaneously forms a partial section of the boundary of the front door opening 215 and also the rear door opening 217, which is associated with many advantages. The press-hardened door ring 210 can have additional soft regions. The additional component 220 can also have at least one such soft region.

[0036] Reference Numbers List

[0037] 100 Molding Blanks

[0038] 110 First Area

[0039] 115 Door opening cutout

[0040] 117 Door opening cutout

[0041] 120 Second Area

[0042] 130(s) connecting tabs

[0043] 210 Door knocker (first component)

[0044] 215 Door Opening

[0045] 217 Door Opening

[0046] 220 Another component (second component)

[0047] S steel plate material

[0048] W soft area

Claims

1. A method for producing a press-hardened door ring (210) and at least one further press-hardened component (220) for a motor vehicle, comprising the following steps: - providing a shaped blank (100) having a first region (110) with a door opening cutout (115), from which a door ring (210) is formed, and a second region (120), from which the further component (220) is formed, wherein the second region (120) is arranged in the door opening cutout (115); - heating the shaped blank (100); - The heated forming blank (100) is placed in a press-hardening tool and a press-hardening process is carried out, during which both the door ring (210) and the other component (220) are transformed into respectively set final geometric shapes and hardened, wherein a separating cut is also carried out in the press-hardening tool to cut off the door ring (210) and the other component (220).

2. The method according to claim 1, It is characterized in that The separating cut is performed before the sheet material (S) cools down.

3. The method according to any one of the preceding claims, It is characterized in that The separating cut is performed before the door ring (210) and / or the additional component (220) are reshaped.

4. The method according to claim 3, It is characterized in that After the separating cut has been carried out, the further component (220) is fixed in the press-hardening tool.

5. The method according to any one of the preceding claims, It is characterized in that The door ring (210) and / or the further component (220) is also contour cut in the press-hardening tool.

6. The method according to any one of the preceding claims, It is characterized in that The formed blank (100) has uniform plate quality and plate thickness.

7. The method according to any one of the preceding claims, It is characterized in that The shaped blank (100) is produced in a preceding step by cutting out from a sheet metal semi-finished product.

8. The method according to any one of the preceding claims, It is characterized in that The manufactured press-hardened door ring (210) has at least one soft area (W).

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