Method for producing adhesive connection

Abstract

The invention relates to a method for producing an adhesive connection (100) between a first component (1) and a second component (2), comprising the following steps in an unfixed sequence:-providing the first component (1) with a pin (10),-providing the second component (2) with a cavity (20), the cavity (20) having an upper opening (21) and a lower opening (22), -positioning the second component (2) at the first component (1), in which the pin (10) is inserted into the cavity (20) through the lower opening (22),-injecting a first adhesive (3) into the cavity (20),-orienting the components (1, 2) relative to each other such that the second component (2) assumes a target position relative to the first component (1),-inserting the second component (2) into the cavity (20) through the lower opening (22). -curing the first adhesive (3), and-obtaining the adhesive connection (100).

Description

Field of the Invention

[0001] The present invention relates to a method for establishing an adhesive connection between a first component and a second component, in particular as components of a motor vehicle lighting device. Background Art

[0002] In modern motor vehicle lighting devices, especially in headlamps, there are high requirements for the precise positioning and orientation of optical components such as lenses or reflectors relative to the associated light-emitting device unit. Here, on the one hand, these high tolerance requirements have to be taken into account during manufacturing, and in addition, the orientation of the optical components must also be kept within the tolerance range during the actual and continuous operation of the lighting device. The optical components or the associated holding parts are usually fixed to the carrier in their target position by means of an adhesive connection, in which, in particular, an adhesive connection is established in which a component-side pin extends as a connecting pin into an adhesive-filled cavity on the carrier. This type of adhesive connection provides the possibility of fine adjustment during the orientation of the optical component, typically when operating the light-emitting device unit and observing the light impression created on the projection surface.

[0003] In the case of using an adhesive connection, it is disadvantageous that the adhesive shrinks in volume during curing, which can cause a change in the adjusted position of the optical component and a corresponding undesired change in the light impression produced by the lighting device. In the prior art, solutions for avoiding the effects associated with adhesive shrinkage are known; for example, WO2021 / 115581A1 and WO2021 / 115582A1 disclose methods for constructing an adhesive connection between a pin and a cavity in the case of using rigid or flexible spacer holders in the bottom of the cavity and pre-fixing the adhesive connection with a rapidly curable ultraviolet (UV) adhesive. Summary of the Invention

[0004] The object of the present invention is to provide an improved solution for a method for establishing an adhesive connection, in which an adhesive connection is constructed between a pin of a first component and a cavity of a second component.

[0005] This object is solved by the method according to claim 1. Advantageous refinements of the invention are given in the dependent claims.

[0006] The present invention includes the following technical teaching, that the method for establishing an adhesive connection comprises the following steps in an unfixed order:

[0007] - Providing a first component having a pin,

[0008] - Providing a second component having a cavity, wherein the cavity has an upper opening and a lower opening,

[0009] - Position the second component at the first component, wherein a pin is inserted into the cavity through the lower opening.

[0010] - Inject a first adhesive into the cavity.

[0011] - Orient the components relative to each other such that the second component assumes a target attitude relative to the first component.

[0012] - Cure the first adhesive, and

[0013] - Obtain the adhesive joint.

[0014] The present invention is based on the idea of inverting a joining assembly known from the prior art having a pin extending into a cavity from above, by providing a cavity having a second lower opening for inserting the pin. The second component is thus positioned above the first component, wherein the pin extends into the cavity from below. This results in particular in the advantage that the amount of adhesive required for constructing the connection can be less than in the adhesive joints of the prior art. In the latter case, there is always a dead volume between the bottom of the cavity and the pin extending into the cavity from above that has to be filled with adhesive. Due to the smaller amount of adhesive and the specific connection geometry, in the adhesive joint established by the method according to the invention, the volume shrinkage of the adhesive during curing is also smaller, thereby achieving improved positional accuracy, i.e., the shrinkage-induced deviation of the second component relative to the pre-adjusted target attitude of the first component is smaller than in the methods of the prior art. In the case of applying the method according to the invention for establishing an adhesive joint between components, the pin or the cavity has a characteristic dimension on the order of 10 millimeters, and the position change of the cavity relative to the pin due to adhesive shrinkage is typically less than 10 micrometers.

[0015] Another advantage of the method according to the invention is the better accessibility of the cavity even after positioning the second component at the first component, since, unlike in the joining assemblies of the prior art, the upper opening of the cavity is not covered by the first component. Thus, the first adhesive and optionally other adhesives can be injected into the cavity through the upper opening without problems after positioning the second component at the first component. Alternatively, the first adhesive can already be injected before positioning the second component at the first component, i.e., before inserting the pin into the cavity.

[0016] The term "cavity" in the present context denotes a suitable receiving space which is suitable for receiving at least one section of an adhesive and a pin. Such a receiving space can be constructed, for example, by a pit-shaped (grubenförmige) recess or a cup-shaped raised molding on the second component. The term "pin" in the present context denotes an element which projects suitably from the first component, in particular in the shape of a dowel, and which is suitable for insertion into the cavity of the second component.

[0017] The method according to the invention is in principle not limited to a specific type of adhesive, and in the present context in particular the term "curing" encompasses any process which causes the adhesive to harden, without restricting generality, in particular all processes of chemical curing (polymerization, addition polymerization, etc.) or physical solidification (drying, cooling, etc.).

[0018] In an advantageous embodiment, the first adhesive is provided as a highly viscous or viscoelastic adhesive. Here, the fluidity of the adhesive is low such that the adhesive does not flow out through the lower opening of the cavity during a process-specific period between injection into the cavity and curing.

[0019] In another embodiment, after the first adhesive has cured, a second adhesive is injected into the cavity and cured. In particular, the first adhesive can only be used to pre-fix the adjusted target attitude of the second component, and the final strength of the adhesive connection is only produced by the second adhesive. For example, the second adhesive is constructed as a two-component adhesive based on polyurethane.

[0020] Advantageously, the first adhesive is cured by irradiation with ultraviolet light (UV). UV curing enables rapid process guidance and can be achieved without problems due to the free access to the cavity via the upper opening for UV radiation.

[0021] For example, the first component and the second component are provided as components of a motor vehicle lighting device, in particular a headlamp, where the first component is provided as a carrier and the second component is provided as an optical component for a light-emitting device unit, in particular a reflector or a lens. In particular, when orienting the components relative to one another, the light-emitting device unit is operated and the resulting light impression is monitored, such that the target attitude of the second component relative to the first component is indicated by obtaining the target light impression. Description of the Drawings

[0022] Other measures for improving the invention are shown below together with the description of preferred embodiments of the invention with the aid of the drawings. In a schematic cross-sectional view:

[0023] Figure 1 A joining assembly with an adhesive connection established according to the invention is shown, and

[0024] Figures 2a to 2d Shows successive steps when establishing an adhesive connection according to the present invention. Detailed description

[0025] Figure 1 Shows a schematic cross-sectional view of an engagement assembly composed of a first member 1 and a second member 2, which are interconnected by means of (at least) two adhesive connections 100 established according to the present invention. As components of a light module of a motor vehicle lighting device, the first member 1 is configured as a carrier and the second member 2 is configured as a lens system. A light-emitting device unit 5 is arranged on the first member 1, and the light-emitting device unit includes a matrix arrangement of LEDs. For the desired efficiency of the light module, a high-precision adjustment of the lens relative to the LEDs (correspondingly outside the shown cross-section) is required, and thus the attitude (i.e., position and orientation) of the second member 2 relative to the first member 1 must correspond as accurately as possible to the relevant target attitude without deviation.

[0026] To construct the two adhesive connections 100, the first member 1 has two pins 10 and the second member 2 has two cavities 20. The cavities 20 are configured as receiving spaces of cup-shaped integrally formed parts on the second member 2 and each have an upper opening 21 and a lower opening 22. The pins 1 respectively extend into the cavities 20 through the lower openings 22, and the adhesive connections 100 are formed by a first adhesive 3 and a second adhesive 4. The position change of the cavities 20 relative to the pins 10 caused by the shrinkage of the adhesive during curing is typically less than 10 micrometers when using the method according to the present invention.

[0027] To illustrate the method according to the present invention, Figures 2a to 2d Shows during Figure 1 successive steps when establishing the adhesive connection 100 in an exemplary engagement assembly.

[0028] Figure 2a Shows the state after the second member 2 is positioned at the first member 1, where the pins 10 are inserted into the cavities 20 through the lower openings 22. The second member 2 is typically held on a manipulator (not shown) and is in an initial attitude, from which the target attitude is adjusted in another method.

[0029] Figure 2bShows the state after the first adhesive 3 is injected into the cavity 20. As shown, the lower opening 22 is geodesically below the upper opening 21 when establishing the adhesive connection, such that gravity pushes the first adhesive 3 in the direction towards the lower opening 22. Therefore, it is preferred to provide the first adhesive 3 as a highly viscous or viscoelastic adhesive such that it does not flow out of the cavity 20 via the lower opening 22 or at least not in a significant amount until it cures.

[0030] Figure 2c Shows the curing of the first adhesive 3 immediately after the members 1, 2 are oriented relative to each other. In the shown state, the second member 2 is in the target attitude relative to the first member 1. When orienting the members 1, 2, in order to find the target attitude, the light emitting device unit 5 is operated (see Figure 1 ) and the resulting light impression is monitored, for example on a spaced-apart projection screen. The target attitude of the second member 2 relative to the first member 1 is indicated by obtaining the target light impression. The curing of the first adhesive 3 is carried out via the upper opening 21 by irradiation with ultraviolet light UV.

[0031] Figure 2d Shows the final adhesive connection 100, wherein after the first adhesive 3 has cured, the second adhesive 4 is injected into the cavity 20 via the freely accessible upper opening 21 and cured. The second adhesive 4 is configured, for example, as a chemically curable two-component adhesive and ensures the required final strength of the adhesive connection 100. Compared to the pin-cavity adhesive connections known in the prior art, the adhesive connection 100 established according to the invention requires a smaller amount of adhesives 3, 4 because in the present case the dead volume at the bottom of the cavity does not have to be filled with adhesive, but rather the layer of the first adhesive 3 directly above the lower opening 22 has already come into contact with the inserted pin 10. Therefore, the shrinkage of the adhesive volume during curing is also smaller than in the adhesive connections of the prior art, thereby achieving a particular precision of the adhesive connection 100 established according to the invention with respect to the adjusted target attitude of the second member 2 relative to the first member 1.

[0032] The invention in its embodiments is not limited to the preferred embodiments given above. On the contrary, various variants are conceivable, which also use the described solution in essentially different types of embodiments. All features and / or advantages derivable from the claims, the description or the drawings (including structural details, spatial arrangements and method steps) can be essential to the invention not only in themselves but also in various different combinations.

[0033] List of reference numerals

[0034] 100 Adhesive connection

[0035] 1 First component

[0036] 10 Pin

[0037] 2 Second component

[0038] 20 Cavity

[0039] 21 Upper opening

[0040] 22 Lower opening

[0041] 3 First adhesive

[0042] 4 Second adhesive

[0043] 5 Light-emitting device unit

[0044] UV ultraviolet light

Claims

1. A method for establishing an adhesive connection (100) between a first component (1) and a second component (2), the method comprising the following steps in an unfixed order: - providing a first component (1) having a pin (10), - Provide a second member (2) having a cavity (20), wherein, The cavity (20) has an upper opening (21) and a lower opening (22), - positioning the second component (2) at the first component (1), wherein the pin (10) is inserted into the cavity (20) through the lower opening (22), - injecting a first adhesive (3) into the cavity (20), - orienting the components (1, 2) relative to each other such that the second component (2) assumes a target attitude relative to the first component (1), - curing the first adhesive (3), and - obtaining the adhesive connection (100).

2. The method according to claim 1, characterized in that, The first adhesive (3) is provided as a highly viscous or viscoelastic adhesive.

3. The method according to claim 1 or 2, characterized in that, After the first adhesive (3) has cured, a second adhesive (4) is injected into the cavity (20) and cured.

4. The method according to any one of the preceding claims, characterized in that, The first adhesive (3) is cured by irradiation with ultraviolet light (UV).

5. The method according to any one of the preceding claims, characterized in that, The first component (1) and the second component (2) are provided as parts of a motor vehicle lighting device, the first component (1) is provided as a carrier and the second component (2) is provided as an optical component for a light-emitting device unit (5), in particular a reflector or a lens.

6. The method according to claim 5, characterized in that, When orienting the components (1, 2) relative to each other, the light-emitting device unit (5) is operated and the resulting light impression is monitored, so that the second component (2) assumes a target attitude relative to the first component (1) by obtaining a target light impression.

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