Method for manufacturing a component with a film hinge and component with film hinge

Abstract

Method for manufacturing a component (2) with a film hinge (3), wherein the component (2) and the film hinge (3) are made of fiber-reinforced plastic, and wherein the component (2) and the film hinge (3) are simultaneously injection molded in an injection mold (1), characterized in that an ultrasound source (7) acts on the film hinge (3) to be formed during injection.

Description

[0001] The invention relates to a method for manufacturing a component with a film hinge, wherein the component and the film hinge are made of fiber-reinforced plastic and wherein the component and the film hinge are simultaneously injection molded in a mold.

[0002] The invention further relates to a correspondingly manufactured component.

[0003] Such components are known in themselves and are used, for example, as housings or packaging. In automotive engineering, for instance, accelerator pedals, which are designed as so-called upright pedals, are equipped with a film hinge that is arranged between a base plate and a control plate.

[0004] The disadvantage of known components with film hinges is that bending stress causes the fibers to break, leading to a relatively rapid failure of the film hinge.

[0005] This can be overcome, for example, by manufacturing the film hinge as a separate component, inserting it into the injection mold, and then overmolding it with the fiber-reinforced plastic as the component is formed.

[0006] German patent application DE 10 2013 020 494 B4 discloses a method for manufacturing a fiber-reinforced plastic component with a film hinge, in which a plastic melt containing the fibers is foamed by means of a gas or a blowing agent before being injected into a mold. This is intended to achieve higher stability and lower weight of the component. The process is relatively complex; a high flexural strength of the film hinge, as required for many components in automotive engineering, is not guaranteed in the long term.

[0007] DE 10 2020 105 907 A1 describes a method for manufacturing a fiber-reinforced plastic component with a film hinge, in which the film hinge is fiber-free. For this purpose, a filter is arranged in a sprue channel associated with the film hinge, which separates the fibers.

[0008] For further information on the state of the art, reference is made to publications US 2022 / 0 144 525 A1, EP 3 083 184 B1 and JP H02- 286 312 A.

[0009] The first objective of the invention is to provide a method for manufacturing a fiber-reinforced plastic component with a film hinge that is simple and inexpensive to implement and guarantees a permanently stable film hinge.

[0010] The problem is solved by the features of claim 1. The component and the film hinge are simultaneously injection-molded in a mold, and during injection molding, an ultrasound source acts on a region of the film hinge being formed. The ultrasound source and the sound waves emitted from it are aligned such that fibers in the aforementioned region align themselves parallel to the bending axis. This prevents the fibers in the film hinge from bending or kinking during use, thus preventing breakage and ensuring the required elasticity and stability over the long term. This means that the film hinge has high strength parallel to the bending axis, and its strength perpendicular to it is not compromised by broken fibers.Because the component outside the film hinge itself is not affected by the ultrasound source, the glass fibers remain randomly arranged here, so that the usual high stability is maintained.

[0011] The dependent claims relate to the advantageous embodiment of the invention.

[0012] In one embodiment, the injection mold is fed with the fiber-reinforced plastic from two sides during operation, with the feed rate on the side of the film hinge being lower than on the opposite side. This allows for the precise positioning of a weld line; this is an interface within the component between an area with an ordered arrangement of the glass fibers and an area with a random arrangement. The weld line is intended to be located between the film hinge and an operating element.

[0013] In a further embodiment, the cross-sectional area of ​​the conductor leading to the side of the film hinge to be formed is smaller than on the opposite side. This allows for a simple way to achieve the lower feed rate due to the higher conductor resistance.

[0014] In another form, the fibers are glass fibers. These are inexpensive, possess the required strength, and are easy to process.

[0015] In a further embodiment, the frequency of the ultrasound source is tuned to the glass fiber reinforced plastic. This results in particularly effective alignment of the fibers.

[0016] The invention is particularly well suited for accelerator pedals of motor vehicles.

[0017] A second objective of the invention is to provide a fiber-reinforced plastic component with a film hinge that is easy and inexpensive to manufacture and has a permanently stable film hinge.

[0018] The second problem is solved by the features of claim 6. The statements made regarding the method apply accordingly.

[0019] The invention is explained in more detail below with reference to the accompanying schematic drawing. The drawing shows: Fig. 1 a longitudinal section through an injection mold for a component and Fig. 2. A representation of fibers in the area of ​​a film hinge.

[0020] As from the Fig. As can be seen, an injection mold 1 for forming a component 2 with a film hinge 3 comprises a mold 4, a feed line 5 which here divides into two partial feed lines 5A, 5B, and means (not shown) for melting plastic, adding fibers 6, here glass fibers, and conveying the mixture of the molten plastic and the fibers 6 to the mold 4. Furthermore, at least one, here two, ultrasonic sources 7 are arranged at one end of the mold 4, which is associated with the film hinge 3.

[0021] Form 3 is designed here in such a way that component 2 can be a standing accelerator pedal for a motor vehicle with a control plate 8, the film hinge 3 and a connecting element 9 to a base plate of the motor vehicle.

[0022] The two partial feed lines 5A and 5B, branching off from feed line 5, are connected to the mold 3. The first of the partial feed lines 5A, which is assigned to a connecting element-side end of the mold 3, has a smaller cross-section than the second of the partial feed lines 5B, so that the respective feed quantities to the mold 3 differ. A weld line 10 is formed in a transition area from the film hinge 3 to the operating plate 8.

[0023] To manufacture component 2, the plastic is melted, mixed with the fibers 6, and pumped into the feed line 5 at a predetermined pressure. From the feed line 5, the flowable plastic containing the fibers 6 is distributed to the sub-feed lines 5A and 5B according to their cross-sections. The ultrasonic sources 7 are switched on. The plastic containing the fibers 6 is distributed evenly within the mold 4; the distribution is chosen such that the connecting element 9 and the film hinge 3 are formed essentially via the first feed line 5A, and the operating plate 8 is formed simultaneously via the second feed line 5B. As a result of the waves emitted by the ultrasonic sources 7, the fibers 6 align themselves parallel to a bending axis of the film hinge 3 in the area of ​​the film hinge 3, as shown in the Fig.The structure is shown very schematically in Figure 2, with only a few fibers 6 indicated. In contrast, the fibers 6 in the control plate 8 are randomly and randomly oriented. The weld line 10 is formed at a transition area between the film hinge 3 with its ordered fibers 6, i.e., those aligned parallel to the bending axis, and the control plate 8 with its randomly arranged fibers 6. Once the mold 4 is filled, the ultrasonic sources 7 are switched off. The mold 2 is cooled as usual so that the plastic solidifies and the finished component 2 can be removed. Reference symbol list 1 injection mold 2 components 3 film hinges 4 Form 5 Supply line / Partial supply line 6 fiber 7 Ultrasound source 8 Control panel 9 Connecting link 10 Binding suture

Claims

[1] Method for manufacturing a component (2) with a film hinge (3), wherein the component (2) and the film hinge (3) are made of fiber-reinforced plastic, and wherein the component (2) and the film hinge (3) are simultaneously injection molded in an injection mold (1), characterized by , that during injection an ultrasound source (7) acts on the film hinge (3) to be formed. [2] Method according to claim 1, characterized by , that a form (4) of the injection mold (1) is fed with the glass fiber reinforced plastic from two sides, wherein the feed quantity to the side of the film hinge (3) is less than to an opposite side. [3] Method according to claim 2, characterized by , that a conductor cross-section leading to the side of the film hinge (3) is smaller than on the opposite side. [4] Method according to any one of claims 1 to 3, characterized by, that the fibers (6) are glass fibers. [5] Method according to any one of claims 1 to 4, characterized by , that a frequency of the ultrasound source (7) is tuned to the glass fiber reinforced plastic. [6] Component (2) with film hinge (3) made of fiber-reinforced plastic, characterized by that it is manufactured according to the method of claims 1 to 5. [7] Component (2) according to claim 6, characterized by , that in an area of ​​the film hinge (3) fibers (6) are aligned parallel to a bending axis. [8] Component (2) according to claim 6 or 7, characterized by , that the fibers (6) are glass fibers. [9] Component (2) according to any one of claims 6 to 8 characterized by that it is an accelerator pedal for a motor vehicle.

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