Control unit housing comprising a shield with push elements having elastic arms parallel to the edge

Abstract

The invention relates to a control unit housing for a motor vehicle headlight, the housing comprising a cover (2), a shield (3), a printed circuit board assembly (PCBA) and a heat sink. The shield, interposed between the cover and the PCBA, comprises a set of electrically conductive push elements (28), each push element comprising one or preferably two arms (32, 34) inclined toward the PCBA, the free end (33, 35) of each arm coming into resilient bearing contact with the ground strip of the PCBA when the housing is assembled, these arms being oriented longitudinally relative to the ground strip. The cover preferably comprises rods (21), which, when the housing is assembled, pass through openings (39) in the shield and bear against a base (31) of the push elements so as to press them against the PCBA.

Description

CONTROL UNIT HOUSING FEATURING A SHIELD WITH PUSH-PUSHER ELEMENTS AND ELASTIC ARMS PARALLEL TO THE EDGE TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a control unit housing for the functions of a motor vehicle headlight.

[0002] More specifically, the invention relates to the constituent parts of this housing and in particular its shield which includes on its peripheral edge a set of metallic push elements with elastic arms parallel to this edge, intended to come to rest against the ground belt of the printed circuit board. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] In the automotive field, control unit boxes (called "drivers" in English) are used to electronically control the various functions of the headlights, for example high beams, low beams, position lights, hazard lights, fog lights…

[0004] Control unit housings typically consist of a metal cover, a printed circuit board (PCB) on which electronic components are assembled (the board is then designated by the acronym PCBA, meaning Printed Circuit Board Assembly), and an aluminum heat sink that dissipates the heat generated by the electronic components via fins extending along its underside. In this case, the metal cover acts as a shield against electromagnetic interference that could affect the electronic components (electromagnetic compatibility, or EMC).

[0005] Control unit housings with plastic covers are also known. In this case, it is necessary to add a separate shield, in the form of an additional metal plate inserted between the cover and the PCBA board, to protect the electronic components from electromagnetic interference.

[0006] The invention relates to this type of control box with a shield independent of the cover.

[0007] In order to achieve satisfactory grounding of the various components of the case, it is important to ensure permanent electrical contact between the ground belt of the PCBA board and the other metal parts of the case, namely the shield and the heat sink.

[0008] Because the shield is simply sandwiched between the cover and the PCBA board, without being fixed to the board, the electrical contact between these two components may be faulty, particularly due to vibrations experienced during vehicle operation. This can lead to headlight malfunctions.

[0009] To avoid this and ensure contact between the metal shield and the ground belt of the PCBA board, shields equipped with metal tabs, located on the periphery of the shield and extending downwards towards the PCBA board, were developed in the prior art.

[0010] When the shield is mounted on the PCBA, these tabs are designed to make elastic contact with the PCBA's grounding band at their ends. They must therefore ensure electrical contact between the shield from which they originate and the grounding band on which they rest. Because they are compressed between the shield and the PCBA, these tabs are subjected to elastic stress and exert a pushing force against the PCBA to maintain electrical contact despite vibrations. Furthermore, this pushing force exerted by the tabs must also press the PCBA against the heat sink, thus ensuring electrical contact between these two components as well.

[0011] Although this earlier achievement appears promising because it seems in theory to solve the technical problem, in reality it presents drawbacks that make it unsuitable from a practical point of view.

[0012] Indeed, the support of the pins against the PCBA's grounding ring is not always guaranteed. Due to manufacturing tolerances of these pins, or in the event of a flatness defect in the shield or the PCBA, it frequently happens that some pins are too short to make contact with the PCBA, or that they barely touch it without being compressed under elastic stress. Consequently, they do not establish electrical contact or do not maintain this contact in the event of vibrations. Furthermore, since they do not exert any thrust against the PCBA, they do not press it against the heatsink and therefore cannot guarantee electrical contact at that point.

[0013] For this reason, this achievement, known from previous art, is not satisfactory.

[0014] There is therefore a need, not yet met, for a more efficient and safer device to ensure electrical contact between the different metallic elements of a headlight control unit housing, even when it is subjected to vibrations related to the operation of the vehicle in which it is installed.

[0015] The invention aims to solve this problem by proposing a control unit housing that does not have these drawbacks.

[0016] To this end, the invention teaches a lighting projector control unit housing comprising a cover, an electromagnetic shield (hereinafter referred to as the shield), and an assembled printed circuit board (also referred to as the PCBA) having a grounding belt, in which the shield is interposed between the cover and the assembled printed circuit board, and in which the shield has at least one electrically conductive, elastic-effect push element, which is in elastic support contact with the grounding belt when the housing is assembled.

[0017] According to the invention, said pusher element comprises at least a first arm, which is inclined towards the assembled printed circuit board and includes a first free end coming into elastic support contact with a first contact area of ​​the ground belt when the housing is assembled, said first arm being oriented longitudinally with respect to the direction of the ground belt at the level of the first contact area.

[0018] Since the pusher element of the invention has an inclined arm oriented longitudinally with respect to the direction of the grounding belt, its bearing area moves longitudinally along the grounding belt in the event of vibrations. It therefore always remains on the grounding belt and does not leave it despite its movement. Electrical contact is thus always maintained.

[0019] Furthermore, because the end of the angled arm moves along the ground belt, it does not approach the center of the PCBA board and is not likely to cause short circuits or damage the electronic components of the PCBA board.

[0020] Finally, since the pusher element is in elastic contact with the PCBA board, it can be compressed to bring the shield closer to the board during case assembly, which facilitates the engagement of the two parts of the cover assembly clips to the heat sink and allows the cover to be easily mounted onto the rest of the case.

[0021] Once this assembly is complete, with the two parts of the cover's mounting clips fully engaged, the pusher element, through spring action, forces the shield and the card apart, and consequently the cover and the heatsink. This force pulls on the two parts of the clips, effectively ensuring a secure closure by eliminating any potential play in the clips.

[0022] Advantageously, said first arm can be a metal blade, preferably made of stainless steel. Such a configuration makes it possible to produce, in a simple and economical manner, a pusher element according to the invention, which is both efficient and durable.

[0023] Advantageously, this metal blade can have a thickness of between 0.3 and 0.6 mm. Such a thickness gives the blade particularly advantageous mechanical properties of flexibility and elasticity to ensure elastic support of its free end on the ground belt despite vehicle vibrations.

[0024] Advantageously, the first free end can be curved in a rounded manner. This creates a linear bearing area, ensuring a large contact surface. Furthermore, the rounded shape maintains contact and provides a consistent linear bearing area, even if vibrations cause the pusher element to tilt along the curve in either direction.

[0025] However, other shapes can obviously be imagined for the first free end of the first inclined arm according to the invention, as long as they allow contact with the ground belt when the housing is assembled, this contact being able to be point, linear or surface depending on the variants.

[0026] Advantageously, the pusher element may include a second arm, which is inclined towards the assembled printed circuit board and which includes a second free end coming into elastic support contact with a second contact area of ​​the grounding belt when the housing is assembled, said second arm being oriented longitudinally with respect to the direction of the grounding belt at the level of the second contact area and extending in the opposite direction to the first inclined arm.

[0027] The pusher element can then advantageously have a symmetrical configuration, with the first arm being axially symmetrical with respect to the second arm.

[0028] With two angled arms extending in opposite directions, the pusher element is more stable and provides better support against the PCBA board. Furthermore, this design allows for two contacts with the ground strap, thus minimizing the risk of electrical connection loss. Indeed, even if vibrations cause the pusher element to tilt and lose one contact with the ground strap, the second contact ensures the continuity of the electrical connection.

[0029] Advantageously, said push element preferably comprises a plate from which the first inclined arm originates and the second inclined arm when the push element comprises them.

[0030] The pusher element can thus be manufactured simply and economically. Furthermore, this plate provides a good, flat, and large bearing surface for the distal end of a rod extending from the cover, if the housing includes one.

[0031] Indeed, the cover may advantageously include a rod extending towards the shield and having a free distal end, this distal end bearing against the plate of the pusher element and pushing it towards the printed circuit board assembled when the housing is assembled.

[0032] By pressing against the pusher element's mounting plate, the rod extending from the cover pushes the pusher element towards the PCBA board, placing the angled arm(s) under elastic stress with their free ends pressed against the grounding ring. Thanks to this push from the rod in the cover, the contact of the free end of the angled arm(s) against the PCBA's grounding ring is guaranteed regardless of manufacturing or assembly tolerances of the various components of the housing (particularly the pusher element). Furthermore, this push from the rod on the pusher element ensures that this contact is maintained even under vibrations, a phenomenon frequently encountered in driving, and a permanent electrical connection is guaranteed.

[0033] In addition, the support of these rods increases the pushing force exerted by the pusher element against the PCBA board and thus ensures that the PCBA board is pressed against the heat sink, thereby also ensuring electrical contact between the grounding belt and the heat sink.

[0034] Advantageously, thanks to this plating, it may even be possible to eliminate the crimp pins that are traditionally placed between the PCBA board and the heat sink.

[0035] When the cover has such a rod, the shield may advantageously have an opening, located above the plate, through which the rod passes when the case is assembled.

[0036] This configuration makes the mounting plate accessible to the rod, even if the pusher element is located under the shield. The rod extending from the cover can thus press against the pusher element's mounting plate even if the shield is interposed between the two, and the advantages mentioned above can be achieved.

[0037] In one embodiment, the cover includes at least one assembly clip comprising a female portion carried by the cover that cooperates with a male portion carried by the heat sink. When the housing is assembled, the pusher element exerts, by spring effect, a force tending to separate the shield from the PCBA board; this force is transmitted to the cover and the heat sink to separate them from each other.

[0038] Indeed, once the case is assembled, with the male and female parts of the assembly clips fully engaged, the push-button elements exert a spring-like force that pulls the shield away from the PCBA board. This force is transmitted to the cover and the heat sink, pushing them apart. This pulling force has the technical advantage of applying pressure to the male and female parts of the assembly clips, thus ensuring a secure closure by eliminating any potential play in the clips. This configuration improves the stability of the assembly and maintains the integrity of the case, even under significant vibrations.

[0039] Advantageously, the pusher element can be a single piece with the shield. Since the shield is metallic, the pusher element can easily be manufactured simultaneously and from the same material as the shield, as an extension of it. No further assembly is required.

[0040] The shield may then include, for example, a linking extension with the pusher element, in the form of a metal strip which starts from a peripheral edge of the shield and is folded downwards and into the inside of the shield, before ending at the pusher element.

[0041] However, a design with an independent push element, added and fixed to the shield, is also conceivable.

[0042] Advantageously, the housing according to the invention can include several push-button elements, distributed over all the peripheral edges of the shield.

[0043] The presence of several push-button elements multiplies the number of contact points between the shield and the ground belt of the PCBA board and ensures the permanence of the electrical connection.

[0044] Furthermore, their distribution around the shield provides good stability and balance to the shield, which rests on the PCBA board in a horizontal, planar arrangement. This distribution also ensures a consistent and even pressure around the perimeter of the PCBA board, guaranteeing effective contact between the PCBA board and the heat sink along its entire circumference.

[0045] Preferably, the push-in elements are evenly distributed around the perimeter of the shield. This even distribution offers the significant technical advantage of providing optimal stability and even balance to the shield relative to the PCBA. This arrangement allows the shield to rest on the board in a perfectly flat and horizontal position, thus preventing any risk of tilting or inclination that could compromise the quality of the electrical contact. Furthermore, this peripheral distribution ensures a uniform and constant pressing force around the entire perimeter of the PCBA, guaranteeing effective and even contact between the board and the heat sink along its entire edge.This uniformity of pressure is particularly advantageous for maintaining the integrity of the electrical contact despite the vibrations to which the housing may be subjected during vehicle operation, thus contributing to the overall reliability of the lighting system.

[0046] The invention and its various variants will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0047] The figures are presented for illustrative purposes only and are in no way limiting to the invention.

[0048] is a schematic perspective view of an example control unit housing in the assembled state.

[0049] is a schematic exploded perspective view of the casing in which the main components of the casing have been shown disassembled and separated from each other.

[0050] is a schematic perspective view of the shield which has been turned over to expose its underside.

[0051] is an enlargement of the framed area of ​​the.

[0052] is a schematic perspective view from below of the lid and shield assembled with each other.

[0053] is an enlargement of the framed area of ​​the.

[0054] is a schematic top view of the PCBA board assembled on the heat sink, on which the contact areas with the push-elements have been shown.

[0055] These are schematic cross-sectional views that illustrate the interaction between a pusher element, the corresponding stem of the cover and the PCBA board during housing assembly, respectively before and after contact between the stem and the pusher element. DETAILED DESCRIPTION

[0056] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0057] For the purposes of this application, the terms "top," "bottom," "upper," and "lower" will be defined according to the orientation of the components on the control unit housing, with the cover being the "highest" part and the heat sink the "lowest" part. It is understood that this orientation will not necessarily be maintained during operation.

[0058] Similarly, a "horizontal" plane will be defined as a plane parallel to the general plane of a room, and "external" or "internal" directions to a room will be defined as directions contained in a horizontal plane and moving away from or towards that room respectively.

[0059] Figures 1 and 2 show an example of a control unit housing 1, in the assembled state on the and disassembled state on the.

[0060] As shown, this case 1 includes a cover 2, a shield 3, a PCBA board 4 and a heat sink 5.

[0061] The various components of the housing 1 are shown schematically in the figures. Certain parts, unrelated to the invention, have been omitted for the sake of simplicity. This is the case, for example, for the electronic components mounted on the PCB (PCBA 4) and the connection devices for these electronic components, which are not shown.

[0062] When the case 1 is assembled, the cover 2 and the heat sink 5 form the outer shell of the case 1, in which the shield 3 and the PCBA board 4 are housed.

[0063] The housing 1 also includes a perimeter seal 6 (also called peripheral seal 6), shown between the PCBA board 4 and the heat sink 5 in the figure. This seal 6 is designed to be housed in a peripheral groove 7 of the heat sink 5, and to be interposed between the peripheral rim 8 of the heat sink 5 and the peripheral rim 9 of the cover 2 to ensure the sealing of the housing 1.

[0064] To close the housing 1 and keep it in the assembled state, external clipping devices, called assembly clips 10, are provided on all the lateral faces 11 of the housing 1. In the example shown, there are two of these assembly clips 10 per lateral face 11 and they include a female part 12 carried by the cover 2 which cooperates with a male part 13 carried by the heat sink 5.

[0065] The female part 12 of the assembly clips 10 shown is in the form of a U-shaped loop 14 which originates from the rim 9 of the cover 2 and extends downwards towards the heat sink 5. The male part 13 includes a projecting wedge 15 with a triangular cross-section which extends over the lateral face of the rim 8 of the heat sink 5 and forms a progressive engagement ramp for the loop 14.

[0066] The cover 2 shown has a main wall 16, substantially flat and rectangular, which forms the upper face of the case 1. At the periphery, this wall 16 is surrounded by an edge 17 which extends downwards and is extended laterally outwards by the rim 9.

[0067] A cylindrical chimney 18, with an opening 19 on its top, rises from the main wall 16 and extends upwards. This chimney 18, preferably surrounded by an annular seal 20, is designed to engage with a complementary opening in a lighting projector (not shown) to establish a connection for controlling its functions. The connection devices necessary for this control (not shown) can be inserted through the opening 19 to connect with the electronic components of the PCBA board 4.

[0068] The lid 2 also includes a set of rods 21, visible in Figures 5, 6 and 7, 8, the function of which will be explained below with reference to these figures. These rods 21 originate on the underside of the main wall 16, extend downwards towards the shield 3, and terminate in a free distal end 22. They are preferentially arranged around the periphery of the main wall 16 and are regularly distributed all around it.

[0069] Advantageously, the cover 2 is made from a single piece of plastic. The loop 14 of the assembly clips 10 is thus slightly deformable, allowing it to be engaged on the triangular protruding wedge 15 of the heat sink 5.

[0070] Shield 3 is a metal part that protects the electronic components of board 4 from electromagnetic interference. It is preferably made from a single piece of sheet metal, preferably stainless steel, cut and bent.

[0071] It comprises a main wall 23, substantially flat and rectangular, surrounded by a peripheral edge 24 extending downwards and preferably formed of a set of juxtaposed and downwardly folded metal returns 25.

[0072] It also includes a central opening 26, for example rectangular, cut in the main wall 23 to allow the passage of the connection devices introduced through the cover 2, and preferably bordered by metal returns 27 extending downwards, intended to separate the electronic components from the connection devices on the PCBA board 4.

[0073] The shield 3 shown also includes a set of push-button elements 28 according to the invention, which are more visible in figures 3 and 4.

[0074] These push-type elements 28 are arranged under the main wall 23, around its periphery. They are advantageously distributed around the entire perimeter of the shield 3 and are, for example, four or five in number per lateral face 11.

[0075] The pusher elements 28 are preferably made in one piece with the peripheral edge 24, each being connected to it by a connecting extension 29. This connecting extension 29 is for example, as shown in figures 3 and 4, a metal strip 30, which starts from the lower end of a metal return 25 and is folded downwards and into the inside of the shield 3, preferably in a rounded way, before ending at the pusher element 28.

[0076] The push-button elements 28 shown include a plate 31, for example rectangular, which extends in line with the connecting extension 29 in a manner substantially parallel to the main wall 23 of the shield 3 which surmounts it.

[0077] A first arm 32 inclined downwards, i.e. in the direction of the PCBA 4, originates from one side of the plate 31 and extends longitudinally with respect to the direction of the edge 24 on which this pusher element 28 is mounted. It terminates in a first free end 33, preferably curved upwards in a rounded manner.

[0078] A second arm 34, inclined downwards (towards the PCBA 4), originates on the other side of the board 31 and runs in the opposite direction to the first arm 32, longitudinally with respect to the direction of the edge 24 on which the pusher element 28 is mounted. It terminates in a second free end 35, also curved upwards in a rounded manner.

[0079] When the housing 1 is assembled, the first free end 33 of the first arm 32 and the second free end 35 of the second arm 34 come into elastic support contact with the ground belt 36 of the PCBA 4 board at the level of a first contact zone 37 and a second contact zone 38 respectively as shown in figures 7 to 9.

[0080] As arms 32 and 34 extend longitudinally from the edge 24 of the shield, they are oriented longitudinally with respect to the part of the mass belt 36 located at the level of these contact zones 37, 38.

[0081] The shield 3 also includes a series of openings 39, provided in the main wall 23 or, for example, as in the example shown, at the junction between the main wall 23 and the peripheral edge 24, so as to be positioned each above the plate 31 of one of the pusher elements 28.

[0082] As can be seen in figures 5, 6 and 8, 9, these openings 39 are also positioned opposite the rods 21 which descend from the main wall 16 of the cover 2. When the shield 3 is engaged in the cover 2, each of these rods 21 passes through one of the openings 39 and is supported by its distal end 22 against the plate 31 of one of the pusher elements 28.

[0083] When all the components of the housing 1 are assembled, the rods 21 push the pusher elements 28 towards the PCBA board 4 and press them against the grounding band 36 by means of their distal ends 22, which bear against the plates 31. As shown in the figure, the arms 32 and 34 of the pusher elements 28 spread apart and flatten due to their inclination and the natural elasticity of the metal bands. The pusher elements 28 are thus placed under elastic bearing stress.

Claims

A lighting projector control unit housing (1) comprising a cover (2), an electromagnetic shield (3) and an assembled printed circuit board (4) having a grounding belt (36), in which the shield (3) is interposed between the cover (2) and the assembled printed circuit board (4), and in which the shield (3) has at least one electrically conductive, elastic-effect push element (28) which is in elastic support contact with the grounding belt (36) when the housing (1) is assembled, characterized in that said push element (28) has at least one first arm (32) which is inclined towards the assembled printed circuit board (4) and includes a first free end (33) coming into elastic support contact with a first contact area (37) of the grounding belt (36) when the housing (1) is assembled,said first arm (32) being oriented longitudinally with respect to the direction of the mass belt (36) at the level of the first contact zone (37). Housing (1) according to claim 1 characterized in that the first arm (32) is a metal blade, preferably made of stainless steel. Housing (1) according to claim 2 characterized in that the metal blade has a thickness between 0.3 and 0.6 mm. Housing (1) according to any one of the preceding claims characterized in that the first free end (33) is curved in a rounded manner. Housing (1) according to any one of the preceding claims characterized in that said pusher element (28) comprises a second arm (34), which is inclined towards the assembled printed circuit board (4) and includes a second free end (35) coming into elastic support contact with a second contact area (38) of the grounding belt (36) when the housing (1) is assembled, said second arm (34) being oriented longitudinally with respect to the direction of the grounding belt (36) at the level of the second contact area (38) and extending in the opposite direction to the first inclined arm (32). Housing (1) according to claim 5 characterized in that said push element (28) comprises a plate (31) from which originates the first inclined arm (32) and the second inclined arm (34) when the push element (28) has them. Housing (1) according to claim 6 characterized in that the cover (2) includes a rod (21) which extends in the direction of the shield (3) and which has a free distal end (22), and in that said distal end (22) bears against the plate (31) of the pusher element (28) and pushes it in the direction of the assembled printed circuit board (4) when the housing is assembled. Housing (1) according to claim 7 characterized in that the shield (3) has an opening (39), located above the plate (31), which is traversed by the rod (21) when the housing (1) is assembled. Housing (1) according to any one of the preceding claims, characterized in that the cover (2) has at least one assembly clip (10) comprising a female part (12) carried by the cover (2) which cooperates with a male part (13) carried by the heat sink (5), and in that when the housing is assembled, said push element (28) exerts, by spring effect, a force tending to move the shield (3) away from the PCBA board (4), this force being transmitted to the cover (2) and the heat sink (5) to move them away from each other. Housing (1) according to any one of the preceding claims characterized in that said pusher element (28) is one piece with the shield (3). Housing (1) according to claim 10 characterized in that the shield (3) has a linking extension (29) with the pusher element (28), in the form of a metal strip (30) which starts from a peripheral edge (24) of the shield (3) and is folded downwards and into the interior of the shield (3), before ending at the pusher element (28). Housing (1) according to any one of the preceding claims characterized in that it comprises several push-button elements (28), distributed over all the peripheral edges (24) of the shield (3). Housing (1) according to the preceding claim, characterized in that the push elements (28) are distributed regularly over all the peripheral edges (24) of the shield (3).

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