Hollow plastic side member and method for producing such a hollow plastic side member

Abstract

The invention relates to a hollow plastic side member (19), which is produced in a fluid-assisted internal pressure injection moulding process, in which, in an injection moulding step, a molten injection moulding compound of the plastic can be injected under pressure and heat into a mould cavity (33) of an injection mould (35), and in an internal pressure moulding step a fluid (G) is introduced into the tool cavity (33), by means of which step a molten plastic core is displaced and a hollow channel (23) is formed in the hollow plastic side member (19). According to the invention, a hollow profile insert (21) is embedded in the plastic material of the hollow plastic side member (19) to increase the component stability, which insert directly or indirectly annularly encloses the hollow channel (21) in the cross-section.

Description

[0001] Description

[0002] Plastic hollow longitudinal member and method for producing such a plastic hollow longitudinal member

[0003] The invention relates to a plastic hollow longitudinal member according to the preamble of claim 1 and claim 5 and to a method for producing such a plastic hollow longitudinal member according to claims 4 and 10.

[0004] DE 10 2019 209 326 A1 discloses a generic hollow plastic longitudinal member manufactured using a fluid-assisted injection molding process. This process comprises an injection molding step in which a molten plastic injection molding compound is injected under pressure and heat into a cavity of an injection mold. The injected injection molding compound solidifies at the mold surface bordering the cavity, while the inner plastic core is still molten. In a subsequent internal pressure molding step, a fluid is introduced into the mold cavity, displacing the molten plastic core, forming a hollow channel in the hollow plastic longitudinal member.

[0005] EP 2 347 920 A1 discloses a support for an interior trim component. DE 10 2011 112 913 A1 discloses an assembly support.

[0006] The object of the invention is to provide a plastic longitudinal hollow beam whose component stability is increased in a simple manner compared to the prior art.

[0007] The object is achieved by the features of claim 1, 4, 5 or 10. Preferred developments of the invention are disclosed in the subclaims.

[0008] The invention is based on a hollow plastic longitudinal member produced in a fluid-assisted injection molding process in which, in one injection molding step, a molten injection molding compound of the plastic is injected under pressure and heat into a cavity of an injection mold. The injected injection molding compound solidifies on the mold surface bordering the cavity, while the inner plastic core is still molten. In a subsequent internal pressure molding step, a fluid is introduced into the mold cavity, displacing the molten plastic core. In this way, a hollow channel is formed in the hollow plastic longitudinal member. According to the characterizing part of claim 1, a hollow profile insert is additionally embedded in the plastic material to increase the component stability of the hollow plastic longitudinal member. The hollow profile insert encloses the hollow channel directly or indirectly in a ring-shaped cross-section.In this way, the hollow channel in the plastic hollow longitudinal member is additionally reinforced with the help of the hollow profile insert part, so that load application points, for example hinges, cover buffers or gas spring connections, can be provided on the plastic hollow longitudinal member.

[0009] In a technical implementation, the hollow profile insert can be constructed in one or more parts, consisting of a shell-shaped insert base body and an insert cross element. The shell-shaped insert base body has a profile base and profile flanks extending upwards from it. The two profile flanks of the insert base body can be connected to each other in a force-transmitting manner via the insert cross element, which is arranged at a distance from the profile base.

[0010] During the injection molding step, the mold cavity, and in particular the inner profile space defined by the hollow profile insert, is completely filled with the molten injection molding compound. Subsequently, the internal pressure molding step is performed, which completely or partially displaces the plastic core located in the profile space of the hollow profile insert, forming the hollow channel. This results in an extremely rigid construction of the hollow plastic longitudinal member with the help of the hollow profile insert.

[0011] Alternatively and / or additionally, the hollow profile insert or any other insert embedded in the plastic material of the hollow plastic longitudinal member can be provided with an additional stiffening structure. Such a stiffening structure can prevent deformation of the insert during the injection molding process and the internal pressure molding step.

[0012] The insert part can, for example, be a flat plastic or sheet metal part. Preferably, the stiffening structure can be a stamped portion formed integrally and from the same material within the insert part.

[0013] In an alternative design variant, the insert part can be constructed from at least two individual segments joined together at a flange connection. In the flange connection, the joining flanges of the two individual segments overlap each other, forming a component-rigid double-wall structure. Preferably, the flange connection can form the stiffening structure. The stiffening structure can protrude from a base section of the insert part by a profile height. It is advantageous in terms of installation space if the stiffening structure protrudes into the hollow channel, whereby the external dimensions of the hollow plastic longitudinal member are not affected by the stiffening structure.

[0014] In a further design variant, a separate additional element can be assigned to the insert part, forming the stiffening structure. The additional element can be connected to joints on the insert part's base section. Furthermore, the additional element can be curved.

[0015] In a technical implementation, the hollow plastic longitudinal member can be part of a tailgate inner part, which is concealed by a tailgate outer part. The tailgate inner part and the tailgate outer part together form a vehicle's tailgate, with the tailgate inner part providing a load-bearing tailgate structure to which tailgate components, such as hinges, lid buffers, or gas spring connections, are attached.

[0016] Embodiments of the invention are described below with reference to the attached figures.

[0017] They show:

[0018] Figures 1 and 2 each show views of a tailgate of a vehicle;

[0019] Figures 3 to 11 each show views of a hollow plastic longitudinal member which is part of a

[0020] tailgate interior part.

[0021] Fig. 1 shows a view from the rear of a two-track vehicle with a tailgate 1. The tailgate 1 closes off a rear cargo area of ​​the vehicle and is hinged to a rear roof cross member of the vehicle at the top of the vehicle via tailgate hinges (not shown). As can be seen from Fig. 2, the tailgate 1 is constructed from an interior tailgate inner part 3 and an exterior tailgate outer part 5. The tailgate inner part 3 forms a load-bearing tailgate structure and is covered by the exterior tailgate outer part 5, concealed from view. In Fig. 2, the tailgate outer part 5 is attached to the tailgate inner part 3 via an adhesive 7. Both the tailgate inner part 3 and the tailgate outer part 5 are manufactured as plastic injection-molded parts.In addition, the tailgate inner part 3 and the tailgate outer part 5 are essentially structurally identical, as disclosed in DE 10 2019 209 326 A1. This means that both the tailgate inner part 3 and the tailgate outer part 5 are enclosed in a frame-like manner around a rear window 17, with a rear window flange 15 (Fig. 2) formed on the inner circumference of the tailgate outer part 5, on which the rear window 17 is supported.

[0022] A core of the invention lies in the special design of the tailgate inner part 2. The tailgate inner part 3 has - analogous to DE 10 2019 209 326 A1 - a plastic longitudinal hollow support 19 with a hollow channel 23 as a reinforcing structure. The plastic longitudinal hollow support 19 extends in the frame circumferential direction (continuously or with interruptions) around the rear window 17 and is shown in cross-section in Figure 2.

[0023] As can be seen from Figure 2, the plastic longitudinal hollow member 19 has a hollow profile insert part 21 that is at least partially embedded in the plastic material 20 of the plastic hollow longitudinal member 19. The hollow profile insert part 21 encloses a hollow channel 23 of the plastic hollow longitudinal member 19 in a ring-shaped cross-section. The inner side of the hollow profile insert part 21, which defines the hollow channel 23, is covered with plastic material 20, which directly defines the hollow channel 23.

[0024] According to Figures 2 or 3, the hollow profile insert part 21 is constructed in two parts, consisting of a shell-shaped insert base body 25 and an insert cross element 27. Both the shell-shaped insert part 39 and the insert cross element 27 are realized, for example, as flat, formed sheet metal parts.

[0025] The shell-shaped insert base body 25 has a profile base 29 and profile flanks 31 raised therefrom. The insert cross element 27 is joined at joints 28 to the two profile flanks 31 of the insert base body 25 (e.g., by welding), so that the two profile flanks 31 are connected to each other via the insert cross element 27 in a force-transmitting manner. Furthermore, as shown in Figure 2, a reinforcing rib 22 made of plastic material 20 is injection-molded onto the upper side of the insert cross element 27.

[0026] A method for producing the hollow plastic longitudinal member 19 shown in Figure 2 is described below with reference to Figures 3 to 7. Accordingly, the hollow profile insert part 21 is first prepared as shown in Figure 3. The hollow profile insert part 21 is inserted into a tool cavity 33 of an injection molding tool 35 in an insertion step (Figure 4). An injection molding step then starts (Figure 5), in which the tool cavity 33 and in particular also a profile space 37 delimited by the hollow profile insert part 21 (Figure 3 or 4) are completely filled with the molten injection molding compound 38. The further course of the process is followed by an internal pressure molding step (Figure 6), in which a gas filling G is introduced under pressure into the tool cavity 33. As a result, the still molten plastic core located in the profile space 37 of the hollow profile insert part 21 is at least partially displaced, forming the hollow channel 23.After the injection molding compound 38 has cured, a removal step is carried out in which the finished plastic hollow longitudinal member 19 (Figure 7) is removed from the injection mold 35.

[0027] A further exemplary embodiment of hollow plastic longitudinal members 19 is described below with reference to Figures 8 to 11. Figure 8 shows a hollow plastic longitudinal member 19 formed with a hollow channel 23, in whose plastic material 20 an insert part 39 is also embedded to increase the component stability of the hollow plastic longitudinal member 19. The shell-shaped insert part 39 is essentially structurally identical to the insert base body 25 according to Figures 2 to 7, namely with a profile base 29 and profile flanks 31 extending upwards therefrom.

[0028] As can be seen from Figure 8, the insert part 39 has an embossed portion 41 in the region of the hollow channel 23. This embossed portion acts as a stiffening structure, preventing deformation of the insert part 39 during the internal pressure forming step. In Figure 8, the embossed portion 41 is formed from the same material and integrally in the profile base 29 of the shell-shaped insert part 39.

[0029] Alternatively, in Figure 9, the insert part 39 is constructed from two individual segments 43 that are firmly connected to one another at a flange connection F (e.g., by welding). At the flange connection F, joining flanges 44 of the two individual segments 43 overlap each other, forming a component-rigid double-wall structure. Furthermore, the joining flanges 44 are angled upwards at a right angle from the profile base 29. In this case, the flange connection F forms the stiffening structure, which prevents deformation of the insert part 39 during the internal pressure forming step.

[0030] As can be further seen from Figures 8 and 9, the embossed portion 41 or the flange connection F protrudes into the hollow channel 23 by a profile height h. In this way, the outer dimension of the plastic hollow longitudinal member 19 remains unchanged despite the embossed portion 41 or the flange connection F.

[0031] In the embodiment shown in Figure 10, a separate additional element 47 is assigned to the insert part 39. The additional element 47 is connected to the insert part 39 at joints 49 and, together with the profile base 29 of the insert part 39, forms a stiffening structure by means of which deformation of the insert part 39 is prevented during the internal pressure forming step. In Figure 10, the additional element 47 is curved between the two joints 49 by a profile height h in the direction of the hollow channel 23.

[0032] In Figure 11, the insert part 39, as in Figure 9, is constructed from two individual segments 43 that are firmly connected to one another at a flange connection F (e.g., by welding). At the flange connection F, the joining flanges 44 of the two individual segments 43 overlap to form a component-rigid double-wall structure. In this case, the flange connection F forms the stiffening structure that prevents deformation of the insert part 39 during the internal pressure forming step. In contrast to Figure 9, in Figure 11 the joining flanges 44 are not angled edgewise from the profile base 29, but rather lie in a horizontal plane together with the profile base.

[0033] List of reference symbols

[0034] tailgate

[0035] Tailgate interior part

[0036] Tailgate outer part

[0037] Glue

[0038] Rear window flange

[0039] rear window

[0040] Plastic longitudinal hollow beams

[0041] plastic material

[0042] Hollow profile insert part

[0043] Reinforcing rib

[0044] hollow channel

[0045] Insert base body

[0046] Insert cross element

[0047] Joining points

[0048] Profile floor

[0049] Profile flanks

[0050] Tool cavity

[0051] injection mold

[0052] Professional Ira at

[0053] Injection molding compound

[0054] Insert part

[0055] Embossing

[0056] Individual segments

[0057] Joining flanges

[0058] Additional element

[0059] Joints F Flange connection h Profile height

[0060] G Gas filling

Claims

Patent claims Plastic hollow longitudinal member (19) which is produced in a fluid internal pressure injection molding process in which, in an injection molding step, a molten injection molding compound (38) of the plastic (20) can be injected under pressure and heat into a tool cavity (33) of an injection molding tool (35), and in an internal pressure molding step, a fluid (G) is introduced into the tool cavity (33), by means of which fluid a still molten plastic core is displaced, specifically with the formation of a hollow channel (23) in the plastic hollow longitudinal member (19), characterized in that, in order to increase the component stability, a hollow profile insert part (21) is embedded in the plastic material (20) of the plastic hollow longitudinal member (19), which insert part encloses the hollow channel (21) directly or indirectly in a ring-shaped cross-section.Plastic hollow longitudinal member according to claim 1, characterized in that the hollow profile insert part (21) is designed in one or more parts, and in particular that the hollow profile insert part (21) is constructed at least in two parts from a shell-shaped insert base body (25) with a profile base (29) and profile flanks (31) raised therefrom and from an insert cross element (27) which connects the two profile flanks (31) of the insert base body (25) to one another in a force-transmitting manner. Plastic hollow longitudinal member according to claim 1 or 2, characterized in that in the injection molding step, the tool cavity (33), in particular the profile space (37) delimited by the hollow profile insert part (21), is completely filled with the molten injection molding compound, and that in the subsequent internal pressure molding step, the plastic core located in the profile space (37) of the hollow profile insert part (21) is completely or partially displaced to form the hollow channel (23).Method for producing a hollow plastic longitudinal member (19) according to one of the preceding claims. A hollow plastic longitudinal member (19), in particular according to one of the preceding claims, which is produced in a fluid-pressure injection molding process, in which, in an injection molding step, a molten injection molding compound (38) of the plastic (20) can be injected under pressure and heat into a mold cavity (33) of an injection mold (35), and in an internal pressure molding step, a fluid (G) can be injected into the mold cavity. (33) is introduced, by means of which a molten plastic core is displaced, specifically forming a hollow channel (23) in the hollow plastic longitudinal member (19), characterized in that an insert part (39) is embedded in the plastic material of the hollow plastic longitudinal member (19) to increase component stability, and in that the insert part (39) has a stiffening structure (41; 47; F) in the region of the hollow channel (23), by means of which deformation of the insert part (39) can be prevented during the injection process and the internal pressure molding step. Hollow plastic longitudinal member according to claim 5, characterized in that the stiffening structure is an embossed portion (41) which is formed of the same material and in one piece in the insert part (39), and / or in that the insert part (39) is a flat plastic or sheet metal part.A hollow plastic longitudinal member according to claim 6, characterized in that the insert part (39) is constructed from at least two individual segments (43) that are connected to one another at a flange connection (F), at which joining flanges (44) of the two individual segments (43) overlap to form a component-stiff double-wall structure, and in that the flange connection (F) forms the stiffening structure (41). A hollow plastic longitudinal member according to claim 5, characterized in that the stiffening structure (41; 47; F) protrudes from the insert part (39) by a profile height (h), and / or in that the stiffening structure (41) protrudes into the hollow channel (23). Plastic hollow longitudinal member according to claim 5, characterized in that the stiffening structure has an additional element (47) which is connected to joints (49) on the insert part (39), and in particular that the additional element (47) is curved by a profile height (h) between the joints (49).Method for producing a plastic hollow longitudinal member (19) according to one of claims 5 to 9.

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