Joining connection, motor vehicle lighting device and joining process

Abstract

A joining connection (1000) between a support frame and a module frame of a motor vehicle lighting device, wherein the support frame forms a first component (1) and the module frame forms a second component (2), wherein the first component (1) and the second component (2) comprise a plastic, wherein the joining connection (1000) comprises a metallic solder (3), wherein the first component (1) has a receiving section (11) with a cavity (10) and the second component (2) has a pin-shaped joining section (21), wherein the solder (3) is at least partially received in the cavity (10) and the joining section (21) extends at least partially into the cavity (10) and the solder (3), wherein the joining section (21) has a positive-locking section (22) such that a positive-locking connection is formed between the second component (2) and the solder (3), and wherein the receiving section (11) has at least one rib (15) has,which extends at least partially into the cavity (10) and the solder (3).

Description

[0001] The present invention relates to a joining connection between a support frame and a module frame of a motor vehicle lighting device, wherein the support frame forms a first component and the module frame forms a second component, wherein the first component and the second component comprise a plastic. Furthermore, the invention relates to a corresponding joining method and a motor vehicle lighting device. STATE OF THE ART

[0002] When installing lighting assemblies in a motor vehicle lighting system, high demands are placed on the precise alignment of the assemblies to one another, which is crucial for the light impression produced by the motor vehicle lighting system. The lighting assemblies, for example a light module or an optical assembly, are connected to a support frame of the motor vehicle lighting system via associated module frames. The adjustment of the lighting components relative to one another is carried out by appropriately positioning the module frames relative to the support frame. In particular, during the positioning of the module frames, the light impression produced by the lighting system is observed on a test screen, and the target position of the module frames is determined based on the achievement of a desired light impression.A joint connection must then be created between the module frame and the supporting frame, which fixes the module frame precisely in the desired position and also has a high level of strength and long-term stability.

[0003] Since module frames and support frames are typically made of plastic, they are bonded together using adhesives in the prior art. A key challenge is compensating for the shrinkage that inevitably occurs during the curing of the adhesive in such a way that no significant deviation of the module frame's position from its target position results. Such adhesive bonds are therefore realized in the prior art using complex, multi-stage processes, for example, using a variety of different adhesives, such as a UV-curing adhesive and additional fixing elements for pre-fixing the module frame, combined with a heat-curing adhesive to achieve the necessary final strength.Such multi-stage bonding processes are disadvantageously error-prone and time- and cost-intensive. In addition, they can potentially impose restrictive boundary conditions on the geometry of the components to be bonded, for example, to ensure sufficient accessibility of an adhesive gap for UV light.

[0004] The document DE 827164 B discloses a fuel tank for small motor vehicles comprising two tank halves which are connected to one another with the interposition of a seal, wherein in particular the edges of the tank halves are undercut and the connection is effected by introducing a casting compound made of easily meltable metal between the edges.

[0005] US 3144710 A discloses a method for joining two metal parts to form a container, comprising the following steps: forming a circular groove in the first metal part and a circular edge in the second metal part, inserting a ring made of a metal with a lower melting point into the groove, rotating the two metal parts relative to each other, pressing the circular edge of the second metal part into the groove in the first metal part until at least the ring in the groove becomes plastic due to frictional heat, stopping the relative rotation of the metal parts, and cooling the metal of the ring in the groove, thereby forming at least one mechanical connection between the metal parts. In particular, the circular groove can be undercut, and the circular edge has a widened end portion.

[0006] Further relevant prior art can be found in US 2 255 184 A and US 6 612 360 B1. DISCLOSURE OF THE INVENTION

[0007] It is therefore the object of the present invention to propose a joint between a support frame and a module frame of a motor vehicle lighting device, wherein the support frame forms a first component and the module frame forms a second component, wherein the first component and the second component are made of a plastic, which ensures high positional accuracy of the joining partners and a high connection strength. Furthermore, the object of the present invention is to propose a method for constructing such a joint that is less prone to errors and can be carried out in a comparatively short process time.

[0008] This object is achieved based on a joint according to claim 1, a motor vehicle lighting device according to claim 6, and a method according to claim 7. Advantageous developments of the invention are specified in the dependent claims.

[0009] The invention includes the technical teaching that the joint comprises a metallic solder.

[0010] The invention is based on the idea of ​​replacing the adhesive used to create joints according to the prior art with a metallic solder, which ensures significantly higher final strength and, in particular, significantly faster processing. Typical solders, for example, low-melting metallic alloys based on lead and / or tin, solidify from their molten state within a few seconds after the heat source is switched off. This advantageously allows the process time for creating such a joint based on a metallic solder to be drastically reduced compared to prior art processes based on the use of adhesives.An inductive heating process is particularly suitable for melting the metallic solder. This process minimizes thermal stress on the plastic joining components and also allows for heating of any joint geometry. Solidified solder also exhibits significantly higher strength than cured adhesives, so that, in principle, a much more robust joint can be created.

[0011] According to the invention, the first component has a receiving section with a cavity, and the second component has a joining section, wherein the solder is at least partially received in the cavity and the joining section extends partially into the cavity and the solder. The receiving section represents the interface on the first component for establishing the connection, wherein the cavity serves to receive the solder and the joining section, which according to the invention has the shape of a pin. During the formation of the joint, the liquid solder is contained within the cavity, thus minimizing contamination of the surrounding component sections or the work area.

[0012] According to the invention, the joining section has a form-fitting section such that a form-fitting connection is formed between the second component and the solder. Such a form-fitting section can, for example, be shaped like an anchor or be realized by introducing one or more blind holes into the joining section. The form-fitting connections between the solder and the first component, on the one hand, and between the solder and the second component, on the other hand, result in an overall joint connection between the first component and the second component.

[0013] According to the invention, the receiving portion has at least one rib, which extends at least partially into the cavity and the solder. The use of one or, in particular, several such ribs serves to maintain the positional accuracy of the two components relative to each other with respect to the adjusted target position when forming the joint. Upon solidification from the liquid phase, the solder undergoes shrinkage, whereby compressive stresses build up in the region of the ribs in the solder, which leads to clamping and securing the position of the solder body and thus of the joining portion of the second component received therein.

[0014] The receiving section preferably has an undercut section such that a positive connection is formed between the first component and the solder. Since the metallic solder cannot establish a resilient, materially bonded connection with a plastic component, it is expedient to establish a positive connection using geometric undercuts. The undercut section can, for example, be shaped such that the cavity takes on the shape of a truncated cone, or the undercut section can have a plurality of blind holes into which the liquid solder penetrates during the formation of the joint and subsequently solidifies.

[0015] In a further advantageous embodiment, the receiving section has a bottom section adjacent to the cavity and having at least one opening, wherein the opening connects an upper side of the bottom section adjacent to the cavity to a lower side of the bottom section, wherein the solder fills the opening and covers the upper side and the lower side of the bottom section, such that a positive connection is formed between the first component and the solder. This embodiment represents an alternative or supplement to the use of a receiving section with an undercut section. The construction of such a joining connection requires the use of a specially shaped counterholder, which is explained in more detail in the description of the associated method according to the invention.

[0016] In an alternative embodiment, the receiving section has a bottom section adjacent to the cavity with at least one opening, wherein the opening has an undercut and connects an upper side of the bottom section adjacent to the cavity to a lower side of the bottom section, wherein the solder fills the opening such that a positive connection is formed between the first component and the solder. In this embodiment, the process also requires the use of a counterholder to close the opening from below while the solder cools.

[0017] The solder preferably has a liquidus temperature within a temperature range of 140°C to 450°C and / or a temperature range of 140°C to 330°C. Solders with liquidus temperatures below approximately 450°C are referred to as soft solders and are usually based on lead, tin, silver, and / or copper alloys. Tin solders typically have liquidus temperatures below 330°C. The use of such low-melting solders is advantageous within the scope of the present invention because it minimizes the thermal stress on the components to be joined, particularly plastic components, and the heating process for melting the solder is less energy- and time-intensive.For the application of the joint according to the invention in a motor vehicle lighting device, the liquidus temperature of the solder used should be at least 140°C, since it must be prevented that the solder undesirably softens during the temperatures of up to 120°C that typically occur during operation of the motor vehicle lighting device.

[0018] The invention also relates to a motor vehicle lighting device comprising a module frame for receiving a light module or an optical module, further comprising a support frame, wherein the module frame and the support frame are connected to one another by means of a joining connection according to one of the aforementioned embodiments.

[0019] Furthermore, the invention relates to a method for joining a support frame to a module frame of a motor vehicle lighting device, wherein the support frame forms a first component and the module frame forms a second component, wherein the first component and / or the second component comprise a plastic, wherein at least the following method steps are carried out: - Providing the first component with a receiving portion, wherein the receiving portion has a cavity, and the second component with a pin-shaped joining portion, wherein the joining portion has a form-fitting portion, and wherein the receiving portion has at least one rib which extends at least partially into the cavity, - positioning the first component relative to the second component, wherein the joining section is at least partially guided into the cavity, - Filling a metallic solder into the cavity, - liquefying the solder by heating it to a temperature above the liquidus temperature, and - cooling the solder and obtaining a joint connection between the first component and the second component, wherein a positive connection is formed between the second component and the solder, and wherein the at least one rib extends into the solder.

[0020] In an advantageous embodiment of the method according to the invention, the first component is provided with a receiving section which has a bottom section adjacent to the cavity and has at least one opening, wherein the opening connects an upper side of the bottom section adjacent to the cavity to a lower side of the bottom section, wherein after the positioning of the first component relative to the second component, a counter-holder is positioned on the receiving section, wherein a cavity is formed between the counter-holder and the lower side of the bottom section, which cavity is connected to the cavity through the opening in the bottom section, such that the solder flows into the cavity after liquefaction.

[0021] In a further embodiment of the method according to the invention, the first component is provided with a receiving section which has a bottom section adjacent to the cavity and has at least one opening, wherein the opening has an undercut and connects an upper side of the bottom section adjacent to the cavity to a lower side of the bottom section, wherein after the positioning of the first component relative to the second component, a counterholder is positioned on the lower side of the bottom section, wherein the counterholder closes the opening to the lower side in such a way that the solder does not flow out of the opening after liquefaction. PREFERRED EMBODIMENT OF THE INVENTION

[0022] Further measures improving the invention are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures: It shows: Fig. 1a a first cross-sectional view of a joint according to the invention, Fig. 1b a second cross-sectional view of the joint connection Fig. 1a, Fig. 1c a top view of the joint connection Fig. 1a, Fig. 2a-e representations of the method according to the invention, and Fig. 3 Representation of a further embodiment of the joining connection according to the invention and of the method according to the invention.

[0023] The Fig. 1a-c show a joint connection 1000 according to the invention, wherein the Fig. 1c a top view and the Fig. 1a,b show corresponding cross-sectional views taken along the Fig. 1c entered section lines AA' ( Fig. 1a) and BB' ( Fig. 1b).

[0024] The joint connection 1000 between the first component 1 and the second component 2 comprises the solder 3. In particular, the first component 1 is formed by a support frame of a motor vehicle lighting device, and the second component 2 by a module frame for receiving a light module or an optical module of the motor vehicle lighting device. Only the sections of the components 1, 2 required to construct the joint connection 1000 are shown here, namely the receiving section 11, which forms the cavity 10, and the joining section 21, which projects into the cavity 10 and the solder 3 received therein. The cavity 10 is delimited by the undercut section 12 and has a substantially frustoconical shape, which is modified by the four radially projecting ribs 15.Due to this undercut shape of the receiving section 11, a positive connection in all spatial directions is established between the first component 1 and the solder 3. Due to the radially projecting ribs 15, the solder 3 is also secured against twisting within the cavity 10. Furthermore, a positive connection in all spatial directions is also established between the second component 2 and the solder 3, since the joining section 21 of the second component 2 has the plate-shaped positive-locking section 22. In the . Fig. Lot 3 is not shown in Figure 1c for the sake of clarity.

[0025] The Fig. 2a-e show schematic representations of the method according to the invention for constructing a further embodiment of the joining connection 1000 according to the invention. Cross-sectional views of the parts and components involved are shown in each case.

[0026] Fig. 2a shows the positioning 100 of the first component 1 relative to the second component 2, wherein the components 1, 2 are to be joined to one another in the illustrated target position. When using the method according to the invention for connecting a module frame to a support frame of a motor vehicle lighting device, this is the lighting target position which is necessary to produce the desired light impression. The first component 1 has the, for example, cylindrical opening 14 in the bottom section 13 of the receiving cutout 11. The bottom section 13 comprises the upper side 13a, which borders on the cavity 10, and the underside 13b. The cup-shaped receiving section 11 according to the invention also has the Fig. 1b-c. From the second component 2, the pin-shaped joining section 21 with the plate-shaped form-locking section 22 protrudes into the cavity 10.

[0027] Fig. Figure 2b shows the positioning 101 of the counterholder 4 below the base portion 13 on the receiving portion 11 of the first component 1. The counterholder 4 has an end portion with a bowl-shaped configuration, which is brought into contact with the base portion 13 at the front end, so that the cavity 40 is formed below the underside 13b of the base portion 13. The cavity 40 is preferably accessible only through the opening 14, which represents a connection between the cavity 40 and the cavity 10.

[0028] Fig. Figure 2c shows the filling 200 of solder 3 into the cavity 10, with the solder 3 here being in the form of granules 31, for example. Alternatively, the solder 3 can also be introduced in the form of a paste or a wire. The granules 31 fill the cavity 10 and trickle through the opening 14 into the cavity 40.

[0029] Fig. Figure 2d shows the liquefaction 300 of the solder 3. The liquefaction 300 occurs by heating the solder 3 to temperatures above its liquidus temperature, preferably by inductive heating or alternatively by laser or infrared irradiation or furnace heating. In the molten state, the liquid solder 30 fills the cavity 40, the opening 14, and a portion of the cavity 10, with the mold closure section 22 and a portion of the joining section 21 of the second component 2 also being enclosed by the liquid solder 30.

[0030] Fig. 2e shows the formation 400 of the joint 1000, which is formed after the solder 3 has cooled and the counterholder 4 has been removed. The counterholder 4 serves exclusively to shape the mushroom-shaped section of the solder 3 below the cavity 10 and is not a component of the joint 1000. Due to the mushroom-shaped section of the solder 3, a positive connection is formed in the vertical direction between the first component 1 and the solder 3, and via the positive-locking section 22 enclosed in the solder 3, a positive connection also exists between the second component 2 and the solder 3. The joint 1000 has a significantly higher strength than adhesive joints from the prior art.The cooling of the solder 3 from the molten phase 30 typically takes place within a few seconds after the heat source is switched off, which results in the advantage according to the invention of an extremely short process time for establishing the joint 1000 compared to adhesive methods used in the prior art.

[0031] Fig. Figure 3 shows a schematic representation of another embodiment of the joining connection 1000 according to the invention and of the method according to the invention. It again shows a cross-sectional view of the parts and components involved. The difference to the Fig. 2a-e lies in the formation of the positive connection between the first component 1 and the solder 3. The opening 14 has an undercut in the form of a truncated cone-shaped contour, whereby a positive connection is formed between the first component 1 and the solder 3, in particular in the vertical direction. The counterholder 4 has a flat upper side, so that when the counterholder 4 is in contact with the base section 13 as shown, the opening 14 is closed on the underside. This prevents the liquefied solder from flowing out of the opening 14, so that after the solder 3 has cooled, the joint 1000 shown results. Preferably, the base section 13 has a plurality of openings 14 with undercuts. The embodiment with an undercut opening 14 offers the advantage of a lower material usage of solder 3 compared to the Fig. Variant shown in 2a-e. List of reference symbols 1000 joints 1 first component 10 Cavity 11 Recording section 12 Undercut section 13 floor section 13a top 13b bottom 14 Opening 15 ribs 2 second component 21 Joining section 22 Form-fitting section 3 lots 30 liquid solder 31 Lot Granule 4 counterholders 40 cavity 100 Positioning the components 101 Positioning the counterholder 200 Filling the solder 300 Liquefying the solder 400 Preservation of the joint connection

Claims

[1] Joining connection (1000) between a support frame and a module frame of a motor vehicle lighting device, wherein the support frame forms a first component (1) and the module frame forms a second component (2), wherein the first component (1) and the second component (2) comprise a plastic, wherein the joining connection (1000) comprises a metallic solder (3), wherein the first component (1) has a receiving section (11) with a cavity (10) and the second component (2) has a pin-shaped joining section (21), wherein the solder (3) is at least partially received in the cavity (10) and the joining section (21) extends at least partially into the cavity (10) and the solder (3), wherein the joining section (21) has a form-fitting section (22) such that a form-fitting connection is formed between the second component (2) and the solder (3), and wherein the receiving section (11) has at least one rib (15),which extends at least partially into the cavity (10) and the solder (3). [2] Joint connection (1000) according to claim 1, characterized by that the receiving section (11) has an undercut section (12) such that a positive connection is formed between the first component (1) and the solder (3). [3] Joint connection (1000) according to claim 1 or 2, characterized by in that the receiving section (11) has a bottom section (13) adjacent to the cavity (10) and having at least one opening (14), wherein the opening (14) connects an upper side (13a) of the bottom section (13) adjacent to the cavity (10) to a lower side (13b) of the bottom section (13), wherein the solder (3) fills the opening (14) and covers the upper side (13a) and the lower side (13b) of the bottom section (13) in such a way that a positive connection is formed between the first component (1) and the solder (3). [4] Joint connection (1000) according to claim 1 or 2, characterized by in that the receiving section (11) has a bottom section (13) adjacent to the cavity (10) and having at least one opening (14), wherein the opening (14) has an undercut and connects an upper side (13a) of the bottom section (13) adjacent to the cavity (10) to a lower side (13b) of the bottom section (13), wherein the solder (3) fills the opening (14) in such a way that a positive connection is formed between the first component (1) and the solder (3). [5] Joint connection (1000) according to one of the preceding claims, characterized by that the solder (3) has a liquidus temperature from a temperature range of 140°C to 450°C and / or from a temperature range of 140°C to 330°C. [6] Motor vehicle lighting device comprising a module frame for receiving a light module and / or an optical module, further comprising a support frame, characterized bythat the module frame and the support frame are connected to one another by means of a joining connection (1000) according to one of the preceding claims. [7] Method for joining a support frame to a module frame of a motor vehicle lighting device, wherein the support frame forms a first component (1) and the module frame forms a second component (2), wherein the first component (1) and the second component (2) comprise a plastic, wherein at least the following method steps are carried out: - Providing the first component (1) with a receiving portion (11), wherein the receiving portion (11) has a cavity (10), and the second component (2) with a pin-shaped joining portion (21), wherein the joining portion (21) has a form-fitting portion (22), and wherein the receiving portion (11) has at least one rib (15) which extends at least partially into the cavity (10), - positioning (100) the first component (1) relative to the second component (2), wherein the joining section (21) is at least partially guided into the cavity (10), - filling (200) a metallic solder (3) into the cavity (10), - liquefying (300) the solder (3) by heating to a temperature above the liquidus temperature, and - cooling the solder (3) and obtaining (400) a joint connection (1000) between the first component (1) and the second component (2), wherein a positive connection is formed between the second component (2) and the solder (3), and wherein the at least one rib (15) extends into the solder (3). [8] Method according to claim 7, characterized byin that the first component (1) is provided with a receiving section (11) which has a bottom section (13) adjacent to the cavity (10) and has at least one opening (14), wherein the opening (14) connects an upper side (13a) of the bottom section (13) adjacent to the cavity (10) to a lower side (13b) of the bottom section (13), wherein after the positioning (100) of the first component (1) relative to the second component (2), a counter-holder (4) is positioned (101) on the receiving section (11), wherein a cavity (40) is formed between the counter-holder (4) and the lower side (13b) of the bottom section (13), which cavity is connected to the cavity (10) through the opening (14) in the bottom section (13) in such a way that the solder (3) flows into the cavity (40) after liquefaction (300). [9] Method according to claim 7, characterized byin that the first component (1) is provided with a receiving section (11) which has a bottom section (13) adjacent to the cavity (10) and has at least one opening (14), wherein the opening (14) has an undercut and connects an upper side (13a) of the bottom section (13) adjacent to the cavity (10) to a lower side (13b) of the bottom section (13), wherein after the positioning (100) of the first component (1) relative to the second component (2), a counter-holder (4) is positioned on the lower side (13b) of the bottom section (13), wherein the counter-holder (4) closes the opening (14) to the lower side (13b) in such a way that the solder (3) does not flow out of the opening (14) after the liquefaction (300).

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