WO2024068814A1

WO2024068814A1 - Hollow plastic side member and method for producing such a hollow plastic side member

Info

Publication number: WO2024068814A1
Application number: PCT/EP2023/076839
Authority: WO
Inventors: Volker Gaßmann
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2022-09-30
Filing date: 2023-09-28
Publication date: 2024-04-04
Also published as: DE102022210374A1

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

Plastic hollow longitudinal beam and method for producing such a plastic hollow longitudinal beam

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.

From DE 10 2019 209 326 A1 a generic plastic hollow longitudinal member is known, which is produced in an internal fluid pressure injection molding process. This process has an injection molding step in which a molten injection molding compound of the plastic can be injected under pressure and heat into a cavity of an injection molding tool. The injected injection molding compound solidifies on the tool surface delimiting the cavity, with the inner plastic core still molten. In a subsequent internal pressure forming step, a fluid is introduced into the tool cavity, by means of which the molten plastic core is displaced, thereby forming a hollow channel in the plastic hollow longitudinal beam.

A carrier for an interior lining component is known from EP 2 347 920 A1. A mounting support is known from DE 10 2011 112 913 A1.

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.

The task is solved by the features of claim 1, 4, 5 or 10. Preferred developments of the invention are disclosed in the subclaims.

The invention is based on a plastic hollow longitudinal member which is produced in an internal fluid pressure injection molding process in which, in an injection molding step, a molten injection molding compound of the plastic is injected under pressure and heat into a cavity of an injection molding tool. The injected injection molding compound solidifies on the tool surface delimiting the cavity, with the inner plastic core still molten. In a subsequent internal pressure forming step, a fluid is introduced into the tool cavity, by means of which the molten plastic core is displaced. In this way, a hollow channel is formed in the plastic hollow longitudinal beam. According to the characterizing part of claim 1, to increase the component stability of the plastic Hollow longitudinal beam also has a hollow profile insert embedded in the plastic material. The hollow profile insert part encloses the hollow channel directly or indirectly in a ring shape in cross section. In this way, the hollow channel in the plastic hollow longitudinal beam 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 beam.

In a technical implementation, the hollow profile insert part can be constructed in one or more parts from a shell-shaped insert base body and an insert cross element. The shell-shaped insert base body has a profile base and profile flanks raised 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.

When the injection molding step is carried out, the tool cavity and in particular the inner profile space delimited by the hollow profile insert part are completely filled with the molten injection molding compound. The internal pressure molding step is then carried out, which completely or partially displaces the plastic core located in the profile space of the hollow profile insert part while forming the hollow channel. In this way, with the help of the hollow profile insert part, an extremely rigid construction of the plastic hollow longitudinal member is achieved.

Alternatively and/or additionally, the hollow profile insert part or any other insert part that is embedded in the plastic material of the hollow plastic longitudinal member can be provided with an additional stiffening structure. With the help of such a stiffening structure, deformation of the insert part can be prevented during the injection process and the internal pressure molding step.

The insert part can, for example, be a flat plastic or sheet metal part. The stiffening structure can preferably be an embossing that is made of the same material and is formed in one piece in the insert part.

In an alternative embodiment variant, the insert part can be constructed from at least two individual segments which are joined together at a flange connection. In the flange connection, the joining flanges of the two individual segments overlap each other to form a rigid double-wall structure. Preferably, the flange connection can form the stiffening structure. The stiffening structure can protrude by a profile height from a base section of the insert part. It is advantageous in terms of installation space if the stiffening structure protrudes into the hollow channel, so that the external dimensions of the plastic hollow longitudinal beam are not influenced by the stiffening structure.

In a further embodiment, a separate additional element can be assigned to the insert part, which forms the stiffening structure. The additional element can be connected to joints on the insert part base section. In addition, the additional element can be curved.

In a technical implementation, the plastic hollow longitudinal member can be part of a tailgate inner part, which is covered from view by an outer tailgate part. The tailgate inner part and the tailgate outer part together form a tailgate of a vehicle, with the tailgate inner part providing a load-bearing tailgate structure on which tailgate components, such as hinges, lid buffers or gas spring connections, are provided.

Embodiments of the invention are described below with reference to the accompanying figures.

Show it:

Figures 1 and 2 are views of a tailgate of a vehicle;

Figures 3 to 11 each show views of a hollow plastic longitudinal beam, which is part of a

tailgate interior part.

In Fig. 1, a two-lane vehicle with a tailgate 1 is shown in a view from the rear of the vehicle. The tailgate 1 closes a rear loading 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 made up of an inner tailgate part 3 inside the vehicle and an outer tailgate part 5 outside the vehicle. The inner tailgate part 3 forms a load-bearing tailgate structure and is covered by the outer tailgate part 5 outside the vehicle, so that it is not visible. In Fig. 2, the outer tailgate part 5 is attached to the inner tailgate part 3 via an adhesive 7. connected. 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 identical in construction 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 closed in a frame-like manner and enclose a rear window 17, with a rear window flange 15 (Fig. 2) being formed on the inner circumference of the tailgate outer part 5, on which the rear window 17 is supported.

A core of the invention consists 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.

As can be seen from Figure 2, the plastic longitudinal hollow beam 19 has a hollow profile insert part 21, which is at least partially embedded in the plastic material 20 of the plastic hollow longitudinal beam 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 inside of the hollow profile insert part 21 delimiting the hollow channel 23 is covered with plastic material 20, which directly delimits the hollow channel 23.

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

The shell-shaped insert base body 25 has a profile base 29 and profile flanks 31 raised from it. The insert cross element 27 is joined at joints 28 to the two profile flanks 31 of the insert base body 25 (for example by welding) so that the two profile flanks 31 are connected to one another in a force-transmitting manner via the insert cross element 27. In addition, according to Figure 2, a reinforcing rib 22 made of plastic material 20 is molded onto the top of the insert cross element 27.

A method for producing the hollow plastic longitudinal beam 19 shown in Figure 2 is described below with reference to Figures 3 to 7. Accordingly, the hollow profile insert part 21 is firstly spread out according to Figure 3. The hollow profile insert part 21 is Insertion step (Figure 4) into a tool cavity 33 of an injection molding tool 35. 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 into the tool cavity 33 under pressure. 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 while forming the hollow channel 23. After the injection molding compound 38 has hardened, a removal step is carried out in which the finished plastic hollow longitudinal member 19 (Figure 7) is removed from the injection molding tool 35.

Plastic hollow longitudinal beams 19 according to a further exemplary embodiment are described below with reference to FIGS. 8 to 11. 8 shows a plastic hollow longitudinal beam 19 formed with a hollow channel 23, in whose plastic material 20 an insert part 39 is also embedded in order to increase the component stability of the plastic hollow longitudinal beam 19. The shell-shaped insert part 39 is essentially shaped in the same way as the insert base body 25 according to Figures 2 to 7, namely with a profile base 29 and profile flanks 31 raised from it.

As can be seen from Figure 8, the insert part 39 has an embossing 41 in the area of the hollow channel 23. This acts as a stiffening structure by means of which deformation of the insert part 39 is prevented during the internal pressure forming step. In Figure 8, the embossing 41 is made of the same material and is formed in one piece in the profile base 29 of the shell-shaped insert part 39.

Alternatively, in Figure 9, the insert part 39 is constructed from two individual segments 43, which 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 one another to form a component-rigid double-wall structure. In addition, 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 by means of which deformation of the insert part 39 is prevented during the internal pressure forming step.

As can be seen from Figures 8 and 9, the embossing 41 or the flange connection F projects into the hollow channel 23 by a profile height h. This way stays the external dimension of the plastic hollow longitudinal member 19 remains unchanged despite the embossing 41 or the flange connection F.

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 joints 49 on the insert part 39 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.

In Figure 11, the insert part 39, as in Figure 9, is made up of 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 one another to form a component-rigid double-wall structure. In this case, the flange connection F forms the stiffening structure by means of which deformation of the insert part 39 is prevented 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 together with the profile base in a horizontal plane.

Reference symbol list

Tailgate

Tailgate inner part

Tailgate outer part

Glue

Rear window flange

Rear window

Plastic longitudinal hollow beams

Plastic material

Hollow profile insert part

Reinforcing rib

hollow channel

Insert base body

Insert cross element

Joining points

Profile floor

Profile flanks

Tool cavity

Injection molding tool

Professional Ira um

Injection molding compound

Insert part

Embossing

Individual segments

joining flanges

Additional element

Joining points F flange connection h profile height

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 a still molten plastic core is displaced, namely 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 encloses the hollow channel (21) directly or indirectly in a ring shape in 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 in at least 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. Hollow plastic longitudinal member (19) in particular according to one of the preceding claims, 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 injected into the tool cavity (33) is introduced, by means of which a molten plastic core is displaced, specifically by forming a hollow channel (23) in the plastic hollow longitudinal member (19), characterized in that an insert part (39) is embedded in the plastic material of the plastic hollow longitudinal member (19) to increase the component stability, and 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. Plastic hollow longitudinal member according to claim 5, characterized in that the stiffening structure is an embossing (41) which is formed of the same material and in one piece in the insert part (39), and/or that the insert part (39) is a flat plastic or sheet metal part. Plastic hollow longitudinal member according to claim 6, characterized in that the insert part (39) is constructed from at least two individual segments (43) which 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). Plastic hollow 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 between the joints (49) by a profile height (h). Method for producing a plastic hollow longitudinal member (19) according to one of claims 5 to 9.