Method for manufacturing a plastic control unit housing for a motor vehicle and associated control unit housing

Abstract

The invention relates to a method for manufacturing a plastic control unit housing for a motor vehicle and a corresponding control unit housing. A printed circuit board (1) is placed between two housing parts (5, 6), and the two housing parts (5, 6) are connected to each other in a media-tight manner with respect to the printed circuit board (1) housed inside. Furthermore, at least one housing part equipped with an external connector housing (5a) is fitted with a connector (7) engaging therein for the peripheral electrical connection of the printed circuit board (1). For this purpose, the connector (7) is received in the external connector housing (5a) and sealed to the outside together with the two housing parts (5, 6) in a media-tight manner. According to the invention, an inner opening (10) remains in the external connector housing (5a) to the interior of the two housing parts (5, 6), which is closed by means of the connector (7) in the installed state.

Description

[0001] The invention relates to a method for manufacturing a control unit housing made of plastic for a motor vehicle, wherein a circuit board is placed between two housing parts and the two housing parts are connected to each other in a media-tight manner with the circuit board received inside, and wherein at least one housing part equipped with an external connector housing can receive a connector engaging therein for the peripheral electrical connection of the circuit board and is sealed media-tight to the outside together with the two housing parts.

[0002] Plastic control unit housings are widely used in or on motor vehicles. Inside, the housing contains a circuit board, which in turn carries a control unit, a controller, or more generally, a control device. In this way, control functions can be implemented, either within the separate control unit housing itself, or by integrating the housing, for example, as a vehicle lock housing, in addition to the circuit board and control unit, also incorporating mechanical components within the housing.In addition to motor vehicle lock housings, the term control unit housing also includes, for example, locking mechanisms for charging plugs and their housings, window regulator drives and their housings, sliding door drives with housings, opening devices or their housings, electromechanical drives for door opening including housings, drives for tailgates including housings, motor vehicle seat drives with housings, to name just a few examples and without limitation.

[0003] The term "plastic control unit housing" is therefore to be understood and interpreted broadly as per the application and is ultimately characterized by the printed circuit board (PCB) placed between the two housing parts, which in turn carries the control unit. The control unit does not necessarily have to be designed as an electronic (integrated) circuit, but can, in principle, be quite simply a switch. A discrete control unit on the PCB is also conceivable in this context.

[0004] In a method for manufacturing a control unit housing according to the prior art defined in DE 197 55 407 C1, the control unit housing comprises a base and a cover, as well as a connector strip. At least two openings are provided in the base and / or cover. At least one of these openings accommodates the connector strip, which is connected to the circuit board. The openings not occupied by connector strips are closed with a cover. A plastic welding process is used for this purpose, by means of which the cover is tightly bonded to the base and the cover. Plastic welding processes, and in particular laser welding, can be used for this purpose.

[0005] The established procedure has generally proven effective, but still offers room for improvement. For example, the hermetic sealing of the housing after manufacturing means that if the welding is incomplete, the entire control unit housing becomes scrap. Considering the internal, and in some cases expensive, electronic components, this is unacceptable from a cost perspective and also violates resource conservation guidelines. The invention aims to remedy this situation.

[0006] The invention is based on the technical problem of providing such a method for manufacturing a control unit housing as well as a control unit housing made of plastic, in which it is possible to carry out a test for media tightness before installation.

[0007] To solve this technical problem, the invention proposes, in a generic method for manufacturing a control unit housing made of plastic, that an inner opening to the interior of the two housing parts remains in the outer connector housing, which is closed by means of the connector in the installed state.

[0008] That is, according to the invention, when the two housing parts are joined in a media-tight manner, the inner opening remains in the outer connector housing. This inner opening is provided and open to the interior of both housing parts, even after the media-tight joining of both housing parts. This allows a plug dummy to be inserted into the outer connector housing instead of the actual plug when it is installed or closed. The plug dummy does not perform the function of the plug and is therefore not equipped with electrical leads. Rather, the plug dummy has the same external dimensions and external routing, if required, as the plug inserted into the outer connector housing when installed.

[0009] Additionally, the dummy connector is typically connected to a pressure line, allowing the interior between the two housing parts to be pressurized (e.g., positive or negative pressure) via the inner opening in the outer connector housing. This enables a leak test of the control unit housing and, in particular, the verification of a consistently tight seal between the two housing parts. In other words, any leaks between the two housing parts can be easily detected and, if necessary, located by applying pressure through the dummy connector.

[0010] In this way, a comprehensive leak test of the plastic control unit housing is possible, reliably preventing any malfunctions during operation, whether immediately or after potentially several years of operation. This is because the leak test ensures that the media-tight connection between the two housing parts exists and that, according to the invention, any moisture ingress through a previously undetected leak is expressly prevented. This applies even, and especially, over long periods.

[0011] Since the circuit board inside the two media-tightly connected housing parts typically contains more or less sensitive electronic components, it is possible to effectively prevent these electrical or electronic components from coming into contact with moisture and thus avoid malfunctions or even complete failure. This increases operational reliability and prevents potential complaints. Furthermore, any defective control unit housings can be rejected outright, and the circuit board and its components can be reused after the housing is opened. This results in a particularly resource-efficient approach and also saves costs.

[0012] In any case, the inner opening remaining in the outer connector housing for the described pressure test, leading to the interior of the two housing parts, is sealed media-tight at the latest when the connector engages in the outer connector housing in its installed state. Using the connector and the conductors connected to it, the circuit board located inside between the two housing parts, with its electrical / electronic components, is contacted, for example, with peripheral components.Since the outer connector housing generally has an internal and circumferential seal to ensure a tight fit of the connector within the housing, it is guaranteed that the connector, when installed, not only seals the housing to the outside but also closes the internal opening between the two housing parts. This is where the main advantages lie.

[0013] To implement this in detail, the housing part equipped with the outer connector housing is usually also equipped with an inner connector that engages with the outer connector housing. This means that, when installed, the connector engaging with the outer connector housing is contacted with the circuit board via this inner connector. The inner connector is generally connected to the outer connector housing, for example, by snapping or clipping it into place. With this connection, the inner opening in the outer connector housing to the interior between the two housing parts remains uncovered, or rather, is defined by this process.

[0014] This means that the inner connector, when connected to the outer connector housing, defines the relevant inner opening. The connection between the inner connector and the circuit board can be made in virtually any way. For example, the circuit board can be connected to the inner connector's contacts. This can generally be done without soldering. That is, the inner connector's contacts advantageously form a solderless connection with the circuit board. Connections between the inner connector's contacts and the circuit board, for example, in the form of an insulation displacement connection (IDC), have proven particularly advantageous. Such an IDC connection is created immediately when the circuit board is inserted into the outer connector housing.

[0015] This simplifies assembly because, to produce the control unit housing, only the remaining housing part, the cover housing part, needs to be adhesively bonded to the outer connector housing part. This adhesive bond can be a plastic welding joint. This can be achieved by applying heat, similar to a plastic welding process, which is generally limited to the edges between the two housing parts being joined.

[0016] Typically, the outer connector housing and the cover housing are adhesively bonded together using laser radiation. For this purpose, the outer connector housing is generally transparent (to laser radiation), whereas the cover housing, due to its opaque nature, largely absorbs the laser radiation, thereby bringing it into a meltable state, at least superficially. In other words, the transparent outer connector housing usually absorbs little or no laser radiation, while the opaque cover housing absorbs the majority of the laser radiation, thus bringing it into a meltable state, at least superficially.

[0017] In this way, the cover housing part, at least along its circumferential edge, transitions to a meltable state on the surface and is thus adhesively bonded to the transparent outer connector housing part. This allows for a completely media-tight design.

[0018] To verify the leak-tight connection between the two housing parts, the assembled control unit housing is tested for leaks. This is done by inserting the previously mentioned dummy connector into the outer connector housing and pressurizing it.

[0019] This means that, via a hose connected to the dummy connector, the interior of the two housing parts is pressurized with either positive or negative pressure relative to the surrounding atmospheric pressure, and the pressure profile is simultaneously measured as a function of the pressure (positive or negative pressure) supplied by a positive or negative pressure source. Based on this pressure profile, it can then be determined relatively reliably whether the media-tight connection between the two device housing parts is sealed or leaks.

[0020] In the event of any leaks, the two housing parts are generally opened, the circuit board inside is removed, and it is installed in a different plastic control unit housing. This prevents potential malfunctions from the outset and ensures the continued functionality of the control unit housing and, in particular, the control circuitry or control unit located on the circuit board. This is where the main advantages lie. - The invention also relates to the control unit housing itself, as described in independent claim 10.

[0021] The invention will now be explained in more detail with reference to a drawing that illustrates only one embodiment; the drawing shows: Fig. 1 the control unit housing according to the invention in the assembled state from a perspective view, Fig. 2A to 2C different process steps for manufacturing the control unit housing, Fig. 3A and Fig. 3B Different views of the outer connector housing part in the area of ​​the outer connector and the inner connector built into it, Fig. 4 the process of welding both housing parts together, Fig. 5A to 5C the assembly process of the inner plug into the outer plug housing part as well as the attachment of the plug dummy for pressure testing and Fig. 6. Pressure testing of the finished plastic control unit housing.

[0022] The figures show a plastic control unit housing for a motor vehicle. Specifically, in this exemplary embodiment, the plastic control unit housing for a motor vehicle is a motor vehicle lock housing, which internally accommodates not only the necessary lock mechanism but also, and in particular, a circuit board 1, which is best viewed in the Fig. 2B can be understood. The circuit board 1 is equipped, for example, with a control unit 2, with the help of which individual lock functions are controlled in the case of the motor vehicle lock and the illustrated motor vehicle lock housing, for example the "electrically opening" function of a locking mechanism 4. In fact, the locking mechanism 4 may be arranged in a vertical leg of the motor vehicle lock housing, whereas the circuit board 1 is arranged in a horizontal leg.

[0023] It can be seen that, in addition to the electronic control unit 2, the circuit board 1 also accommodates an emergency power source 3 in the form of two capacitors, according to the exemplary embodiment. With the aid of the emergency power source 3, an emergency opening of the lock 4 can be triggered in the event of a failure of a vehicle battery or accumulator. The control unit 2 on the circuit board 1 may also be responsible for this. The lock 4 itself, as is generally the case, consists of a rotary latch and a pawl interacting with it. Furthermore, an electric motor drive, not explicitly shown, which can be actuated by the control unit 2, is provided inside the lock housing. This drive allows the lock 4 to be opened electrically or in an emergency. In the latter case, the necessary energy is supplied by the emergency power source 3.

[0024] The lock housing, or more generally the control unit housing, made of plastic according to the invention comprises two housing parts 5 and 6. One housing part 5 is equipped with an outer connector housing 5a. An inner connector 7 can be plugged into the outer connector housing 5a when installed. For this purpose, the outer connector housing 5a is equipped with a connector located only in the Fig. 3B is equipped with the internal and circumferential seal 8 shown. Since the two housing parts 5, 6 are connected to each other in a media-tight manner – as will be described in more detail below – when the plug 7 is inserted into the external connector housing 5a in the installed state, it is ensured that the control unit housing is sealed in a media-tight manner. This is because, on the one hand, the two housing parts 5, 6 are connected to each other in a media-tight manner, usually by plastic welding, and on the other hand, the external connector housing 5a is also sealed in a media-tight manner by the plug 7, when inserted in the installed state, together with the circumferential seal 8. According to the exemplary embodiment, the external connector housing 5a, like the plug 7, is designed in two parts, which is of course only an example and is in no way a limitation.

[0025] Plug 7, in turn, only shows in the Fig. 1. Electrical lines are visible, by means of which the control unit 2 on the circuit board 1 inside the vehicle lock housing can communicate with a body-side control unit. For example, the body-side control unit sends corresponding release signals to the lock-side control unit 2 on the circuit board 1 when a user wishing to gain access and authorized approaches a vehicle equipped with the vehicle lock and the vehicle lock housing.

[0026] The electrical connection between connector 7 and circuit board 2 is established via an inner connector 9 that engages in the outer connector housing 5a. The inner connector 9 can be easily adapted to specific requirements because it is a plug-in or add-on component. This allows for the realization and implementation of vehicle-specific features, enabling virtually any vehicle to be equipped with the corresponding vehicle lock housing and lock designed in this way. The inner connector 9, which engages in the outer connector housing 5a, serves for the peripheral electrical connection of the circuit board 2 and is sealed to the outside, together with the two housing parts 5 and 6, in a media-tight manner. This is ultimately ensured by the internal connector 9 in its installed state, as shown in the diagram. Fig. 1 Plug 7 inserted into the external plug housing 5a together with the circumferential seal 8 provided inside the external plug housing 5a.

[0027] According to the exemplary embodiment, the design is such that an inner opening 10 remains in the outer connector housing 5a even after the installation of the inner connector 9 and the media-tight connection of the two housing parts 5, 6. This inner opening 10 is realized in or on the inner connector 9 and ensures that, even when the inner connector 9 is installed in the outer connector housing 5a, the interior between the two housing parts 5, 6 can communicate with the exterior or the ambient air, namely via the inner opening 10, which opens towards the interior of the two housing parts 5, 6. However, this inner opening 10 is closed off by means of the connector 7 in the installed state, as shown in the illustration. Fig. 1. Closed. Because in this installed state, the plug 7, in conjunction with the circumferential seal 8 in the outer plug housing 5a, ensures that the outer plug housing 5a is sealed media-tight and hermetically from the outside. This also applies to the inner opening 10.

[0028] To realize and implement this in detail, the procedure is as described in the individual sections. Fig. The process steps 2A to 2C are illustrated in detail. First, the housing part 5, equipped with the outer connector housing 5a, is additionally fitted with the inner connector 9, which engages in the outer connector housing 5a. For this purpose, the inner connector 9 is connected to the outer connector housing 5a. According to the exemplary embodiment, the connection is made such that the inner connector 9 is positioned as shown in the supplementary illustration in the Fig. 5A is first inserted into a recess of the outer plug housing part 5 adjacent to the outer plug housing 5a.

[0029] The inner connector 9 is then moved towards the outer connector housing 5a, as can be seen when transitioning from the Fig. 5A to Fig. 5B and can be traced by the arrow there. This causes the inner connector 9 to snap or clip into the outer connector housing 5a. In principle, other connections between the inner connector 9 and the outer connector housing 5a are also conceivable, for example, a plastic weld. However, a simple and quick-to-install snap-fit ​​or clip connection is usually used, especially since this also makes it easy to define the inner opening 10 in or on the inner connector 9. In the exemplary embodiment, the inner opening 10 is a slot-like opening in the inner connector 9. In principle, however, the inner opening 10 can also be defined on the edge between the inner connector 9 and the outer connector housing 5a during or after the installation of the inner connector 9 into the outer connector housing 5a.

[0030] In either case, the inner plug 9, when connected to the outer plug housing 5a, defines the inner opening 10. Thus, as shown in the illustration, Fig. 5C or according to the Fig. 6. The possibility exists to subsequently insert a plug dummy 7' into the outer connector housing 5a instead of the plug 7. The plug dummy 7' corresponds to the plug 7 in its external dimensions, so that when the plug dummy 7' is inserted into the outer connector housing 5a, a media-tight connection is observed between the plug dummy 7' and the outer connector housing 5a. If positive or negative pressure is now supplied to the interior of the housing between the two housing parts 5, 6 from a pressure source 12 via a hose 11 connected to the plug dummy 7', it can be easily determined, depending on the pressure profile, whether the media-tight welded connection between the two housing parts 5, 6, which will be described in more detail below, is properly executed and has no leaks.

[0031] In fact, returning to Fig. 5B or to Fig. 2A After mounting the inner connector 9, the circuit board 1 is first placed inside the outer connector housing part 5. During this process, the circuit board 1 is simultaneously connected to the inner connector 9. For this purpose, the inner connector 9 has plug contacts 13, which, according to the exemplary embodiment, are designed to be raised and are connected to corresponding mating plug contacts 15 of the circuit board 1. This can be done via a respective insulation displacement connection or generally without soldering. A soldered connection between the plug contacts 13 of the inner connector 9 and the mating plug contacts 15 of the circuit board 1 is also possible and conceivable.In addition to these plug contacts 13, the inner plug 9 also has front-side plug contacts 14, which are contacted with mating plug contacts inside the plug 7 (not explicitly shown) as soon as the plug 7 is inserted into the outer plug housing 5a in the installed state, as shown in the figure. Fig. 1 is plugged in.

[0032] Following the assembly of the circuit board 1 inside the outer connector housing part 5 according to the illustration in the Fig. 2B, the additional housing part 6, the cover housing part 6, is connected to the outer connector housing part 5 and adhesively coupled to it. This is done via a plastic weld between the two housing parts 5 and 6, specifically in their respective edge regions. This plastic weld between the two housing parts 5 and 6 is described in detail in the Fig. 4 reproduced.

[0033] The plastic weld between the two housing parts 5 and 6 is manifested in a weld contour 16, which, according to the exemplary embodiment, is designed as a laser weld contour. The laser weld contour 16 is implemented such that a laser, for example an infrared laser, can penetrate the outer connector housing part 5, which is transparent to the laser radiation. In contrast, the cover housing part 6 is opaque to the laser radiation and consequently absorbs the infrared radiation emitted by the laser. Since the laser radiation is sharply focused on the connection area or edge area between the two housing parts 5 and 6 and defines the weld contour 16, the two housing parts 5 and 6 can be coupled together in a media-tight manner by moving the laser along the weld contour 16 using a 3D movement unit, following the outline of the outer connector housing part 5, according to the exemplary embodiment.As a result, along the weld contour 16, at least the opaque cover housing part 6 melts locally in the area of ​​the weld contour 16 and both housing parts 5, 6 are joined together in a media-tight manner.

[0034] To verify or ensure that the two housing parts 5, 6 are indeed media-tightly coupled to each other, the control unit housing is assembled according to the illustration in the Fig. 2C the plug dummy 7' according to the Fig. 5C or Fig. 6 is inserted into the outer connector housing 5a in a sealing manner. If the connector dummy 7' is then subsequently pressurized or vacuumed via the pressure source 12 and the hose 11, and thus through the inner opening 10, the area between the two housing parts 5, 6 can be pressurized or vacuumed, any leaks that indicate a faulty media-tight connection between the two housing parts 5, 6 can be easily detected.

[0035] As an example, when the interior space between the two housing parts 5 and 6 is pressurized, the pressure is measured using a measuring device (not shown). Alternatively, the pressure source 12 could first pressurize the interior of the two housing parts 5 and 6 with overpressure or underpressure, then be switched off, and subsequently measure whether and for how long the overpressure or underpressure is maintained inside between the two housing parts 5 and 6 using the measuring device. Either way, this allows conclusions to be drawn as to whether the media-tight plastic weld or the weld contour 16 has been produced correctly. If not, the two housing parts 5 and 6 can be separated, and the circuit board 1 inside, with its electrical / electronic components, at least the control unit 2 and the emergency power source 3, can still be used. This is where the main advantages lie. Reference symbol list 1 circuit board 2 Control unit 3 Emergency power source 4 locks 5, 6 housing parts 5a External connector housing 7 internal plugs 7' Plug dummy 8 Seal 9 internal plugs 10 Inner opening 11 hose 12 Pressure source 13 plug contacts 14 plug contacts 15 mating contacts 16 Laser welding contour QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 197 55 407 C1

[0004]

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