COOLING SOCKET OF A LIGHT MODULE FOR MOTOR VEHICLES AND LIGHT MODULE FOR MOTOR VEHICLES

Description

technical field

[0001] The invention relates to the field of heat sinks for automotive lighting modules. It also relates to automotive lighting modules incorporating such a heat sink, and in particular to automotive lighting and / or signaling modules. Previous technique

[0002] Automotive lighting modules, particularly lighting and / or signaling modules, contain components, such as light sources or light source control elements, that generate heat when activated. To ensure the performance of these modules, it is essential to cool them. Overheating of these components, especially the light sources, can degrade the shape of the light beam emitted by the module.

[0003] To cool light modules, heat sinks are commonly used. In particular, heat sinks with multiple fins extending along a direction of extension from a base to a free end are known. The thickness of these fins, measured transversely to the direction of extension, decreases continuously from the base to the free end. This continuous decrease in fin thickness from the base to the free end results in a constant draft angle along each of the two transverse sides of the fins. The draft angle is defined for each of the two transverse sides of the fins by the angle formed between the respective transverse side of the fin and the direction of extension of the fin.

[0004] The draft angle typically has a value greater than or equal to 2°, which allows for a reduction in fin thickness, facilitating the injection and demolding of the heat sink. However, such a heat sink has the disadvantage of being too bulky to be integrated into certain lighting modules where space is particularly limited.

[0005] It is possible to reduce the draft angle to less than 2°, for example to 1°, while simultaneously decreasing the thickness of the fin bases and maintaining the spacing between successive fins at their bases. The fins can then be placed closer together, allowing more fins to be positioned within a smaller volume. This reduces the overall size of the heat sink while maintaining similar heat dissipation performance. However, this approach presents challenges during the injection molding and demolding of the heat sink.

[0006] Indeed, it is difficult to guarantee that the material forming the fins reaches the free ends of the fins during injection molding due to the thinness of their base and, more generally, the thinness of the fins themselves. Consequently, the fins do not conform well to the shape of the injection mold and therefore do not always have the desired form. Furthermore, due to the shallow draft angle, demolding the heat sink is delicate and can lead to wear problems on either the heat sink or the injection mold.

[0007] Documents US2020 / 018458 A1 and WO2021 / 105058 A1 both describe automotive light modules incorporating a prior art radiator. Description of the invention

[0008] The invention aims to overcome at least one of the drawbacks of the aforementioned prior art. More specifically, the invention aims to provide a compact heat sink, capable of dissipating the heat emitted by the components of the lighting module in which it is intended to be mounted, and easy to manufacture, particularly easy to injection mold and demold. The invention also aims to provide a lighting module incorporating such a heat sink.

[0009] According to a first object, the invention provides a heat sink for a vehicle lighting module according to claim 1. In particular, the heat sink comprises at least one cooling protrusion extending between a base and a free end in an extension direction, and having a thickness in a direction transverse to the extension direction, the thickness of the cooling protrusion decreasing from the base to the free end. The heat sink is notable in that the cooling protrusion comprises a first portion and a second portion, the first portion being located between the base and the second portion, and the second portion being located between the first portion and the free end, the decrease in the thickness of the cooling protrusion being greater in the second portion than in the first portion.

[0010] The term "a greater decrease in the thickness of the cooling protrusion in the second portion than in the first portion" means that, if we consider a portion of the first portion of a given height taken along the direction of extension, and a portion of the second portion of the same height as the given height of the portion of the first portion, each of the first and second portions having a lower end facing the base of the cooling protrusion and an upper end facing the free end of the cooling protrusion, then the difference between the thickness of the cooling protrusion at the lower end of the portion of the first portion and the thickness of the cooling protrusion at the upper end of the portion of the first portion is greater than the difference betweenthe thickness of the cooling protrusion at the lower end of the second portion and the thickness of the cooling protrusion at the upper end of the second portion.

[0011] Thus, the decrease in thickness of the cooling protrusion from its base to its free end is not constant. Therefore, it is possible to design a protrusion base thick enough to ensure the flow of the heat sink material into the mold during injection, while maintaining a limited overall size. Indeed, even if the protrusion base is thicker, and therefore bulkier, than a heat sink with a constant draft angle (for example, less than 2° along all transverse sides of the cooling protrusion), having a second section with a greater decrease in thickness than the first allows for a sufficient reduction in the overall thickness of the cooling protrusion as it extends from the base.

[0012] According to one variant, the heat sink has a plurality of cooling protrusions along the transverse direction.

[0013] Thanks to the invention, it is possible to position more cooling protrusions within the same footprint. Indeed, to position more cooling protrusions within the same footprint, the distance between two successive cooling protrusions at their base, measured in the transverse direction, is reduced. However, due to the greater reduction in the thickness of the cooling protrusions in the second portion compared to the first, the distance between two successive cooling protrusions in their second portion is greater than the distance between these two successive cooling protrusions in the first portion. Thus, in the second portion, and therefore closer to the free ends of the cooling protrusions, the distance between the two cooling protrusions is sufficiently large to to favorThe convection between the cooling protrusions promotes outward radiation from the heat sink. Indeed, if the cooling protrusions were too close together, this would impede convection due to pressure drop and negate outward radiation, as the radiation would be absorbed within the heat sink, between the cooling protrusions. Thanks to this invention, the heat sink's efficiency is therefore maintained in a smaller footprint than that of the prior art.

[0014] According to one variant, the bases of two successive cooling protuberances are spaced along the transverse direction by the same distance.

[0015] According to one variant, the cooling protrusion is formed by a fin or a pin.

[0016] According to the invention, the cooling protrusion comprises a third portion located between the second portion and the free end, the decrease in the thickness of the cooling protrusion in the third portion being less than the decrease in the thickness of the cooling protrusion in the second portion.

[0017] The second portion is then located between the first portion and the third portion.

[0018] For example, the decrease in the thickness of the cooling protrusion in the third part may be identical to the decrease in the thickness of the cooling protrusion in the first portion.

[0019] According to one variant, the reduction in the thickness of the cooling protrusion is constant in the first and second portions. If the cooling protrusion has a third portion, the reduction in its thickness can also be constant in that third portion.

[0020] The mold for injecting the cooling protrusion is then simpler to make.

[0021] According to the invention, the cooling protrusion comprises a first transverse side and a second transverse side, opposite to the first transverse side.

[0022] The first and second transverse sides correspond to the edges of the cooling protuberance taken on a section of the cooling protuberance by a plane including the extension direction and the transverse direction.

[0023] The first portion includes a first primary draft angle formed between the first transverse side of the cooling protrusion in the first portion and the extension direction, and the second portion includes a second primary draft angle formed between the first transverse side of the cooling protrusion in the second portion and the extension direction, with the first primary draft angle being less than the second primary draft angle. The third portion includes a third primary draft angle formed between the first transverse side of the cooling protrusion in the third portion and the extension direction, with the third primary draft angle being less than the second primary draft angle, and possibly the same as the first primary draft angle.

[0024] According to one variant, the draft angle along a second transverse side of the cooling protrusion, opposite the first transverse side, is constant. By "constant" is meant that it is identical for each portion.

[0025] Alternatively, the first transverse side is symmetrical to the second transverse side with respect to an axis of symmetry parallel to the direction of extension.

[0026] Therefore, the draft angle along the second transverse side of the cooling protuberance follows the same pattern as the draft angle along the first transverse side of the cooling protuberance. Specifically, the first portion includes a first secondary draft angle formed between the second transverse side of the cooling protuberance in the first portion and the extension direction, and the second portion includes a second secondary draft angle formed between the second transverse side of the cooling protuberance in the second portion and the extension direction. Furthermore, the first primary draft angle is identical to the first secondary draft angle, and the second primary draft angle is identical to the second secondary draft angle.If applicable, if the cooling protrusion has a third portion, then the third portion includes a third secondary draft angle formed between the second transverse side of the cooling protrusion in the third portion and the extension direction, and the third primary draft angle is identical to the third secondary draft angle.

[0027] According to one variant, the heat sink includes at least one upper cooling protrusion and one lower cooling protrusion, and the upper and lower cooling protrusions are aligned and extend in the same direction of extension, in opposite directions.

[0028] Specifically, each of the upper and lower cooling protrusions has a base and a free end, and the base of each upper and lower cooling protrusion rests on an opposite face along the extension direction of a heat sink base. The upper and lower cooling protrusions thus extend on either side of the base.

[0029] If applicable, the upper and lower cooling protrusions each have a height measured along the extension direction. In one variant, the height of the upper cooling protrusion is equal to the height of the lower cooling protrusion. In a second variant, the height of the upper cooling protrusion differs from the height of the lower cooling protrusion.

[0030] The height of the cooling protrusions is thus adapted to the available space in the light module in which the heat sink is integrated.

[0031] According to one variant, the heat sink includes a joint plane extending in a longitudinal plane, perpendicular to the direction of extension.

[0032] The parting line corresponds to the area where the two parts of the mold meet. Specifically, the upper and lower fins extend on either side of the parting line. Preferably, the base of the heat sink is located within the parting line.

[0033] According to a second object, the invention proposes a light module for motor vehicles comprising a heat sink according to the first object of the invention.

[0034] According to one variant, the lighting module includes: at least one light source configured to emit a light beam; at least one printed circuit board on which the light source is placed; at least one optical element configured to deflect and / or project the light beam emitted by the light source; and the heat sink is configured to cool said at least one light source.

[0035] In one variant, the printed circuit board is placed on the heat sink. The heat sink is thus in indirect contact with the light source(s), which allows for efficient cooling of the light source(s).

[0036] According to one variant, the heat sink's joint plane is parallel to the printed circuit board. Brief description of the drawings

[0037] Other features and advantages of the invention will become more apparent upon reading the following description, given by way of illustrative and non-limiting example, and the accompanying drawings, among which: [ Fig. 1 ] There figure 1 represents a heat sink according to a first object of the invention, comprising a plurality of fins; [ Fig. 2 ] There figure 2 represents a cross-section of a rear view of the heat sink shown in figure 1 ; Fig. 3 ] There figure 3 schematically represents the fins of the heat sink figures 1 and 2 ; Fig. 4 ] There figure 4 schematically represents an alternative fin configuration for a heat sink according to a variant of the first object of the invention; [ Fig. 5 ] There figure 5 represents a light module for a motor vehicle according to a second object of the invention comprising a heat sink as described in figures 1 to 3, a reflector and a projection lens; [ Fig. 6 ] There figure 6 represents the light module of the figure 5 in which the reflector has been removed, revealing a printed circuit board and light sources. Detailed description

[0038] In the following description, longitudinal direction L will be understood as the direction in which the vehicle moves, oriented from back to front, transverse direction T will be understood as the direction extending transversely to the vehicle and which is perpendicular to the longitudinal direction L, and vertical direction V will be understood as the direction extending from bottom to top of the vehicle and which is perpendicular to the longitudinal direction L and to the transverse direction T. These directions are represented by the trihedron L, V, T in the figures.

[0039] There figure 1represents a heat sink 10 for a light module in a motor vehicle. As will be seen later, the heat sink 10 is intended to be mounted in a light module 20, which is itself intended to be mounted in a motor vehicle. In the following description, the longitudinal orientation L, transverse orientation T, and vertical orientation V given with reference to the heat sink 10 and the light module 20 correspond to the orientation that the heat sink 10 and the light module 20 have when mounted on the vehicle.

[0040] The heat sink 10 has a plurality of cooling protrusions. In the illustrated example, the cooling protrusions are formed by fins 100. It is understood that other cooling protrusions could be used, such as studs. In the remainder of this description, the term fins will be used to refer to the cooling protrusions of the heat sink 100.

[0041] The heat sink 10 has a base 11 from which the fins 100 extend. In particular, each fin 100 extends between a base 110 and a free end 111 along an extension direction E (shown on the figure 2 ), the base 110 of the fin being located on the side of the base 11 of the heat sink 10. In the illustrated example, the extension direction E of the fins 100 corresponds to the vertical direction V.

[0042] The heat sink 10 includes a parting line P extending in a longitudinal plane, perpendicular to the extension direction E. The parting line P corresponds to the plane in which the two parts of the mold used during the injection of the heat sink 10 are joined. Preferably, the base 11 of the heat sink 11 is in the parting line P.

[0043] The fins 100 of the heat sink 10 comprise upper fins 100a and lower fins 100b. The base 110 of each of the upper fins 100a and lower fins 100b rests on an opposite face along the extension direction E of the base 11 of the heat sink 10. The upper fins 100a and the lower fins 100b thus extend on either side of the base 11 of the heat sink 10.

[0044] In particular, the upper fins 100a extend from their base 110 at the level of an upper face of the base 11 upwards in the vertical direction V to their free end 111, and the lower fins 100b extend from their base 110 at the level of an lower face of the base 11, opposite to the upper face of the base 11 in the extension direction E, downwards in the vertical direction V to their free end 111.

[0045] The upper fins 100a and lower fins 100b are aligned. In other words, each upper fin 100a extends in the same direction of extension E and in the opposite direction to a lower fin 100b. According to a variant covered by the invention, but not shown, an upper fin 100a might not be aligned with a lower fin 100b, and conversely, a lower fin 100b might not be aligned with an upper fin 100a.

[0046] In an unrepresented variant, the heat sink 10 could comprise only upper fins 100a or only lower fins 100b.

[0047] Each fin 100 has a height in the extension direction E. The height of the fins 100 depends on the available space in the light module in which the heat sink 10 is intended to be mounted. Thus, the upper fins 100a and / or the lower fins 100b may all have the same height ha. Alternatively, the upper fins 100a and / or the lower fins 100b may have different heights ha. As illustrated in the non-limiting example shown in figures 1 and 2, several upper fins 100a have the same height ha, while other upper fins 100a have a different height ha, and all lower fins 100b have the same height hb, it being understood that some lower fins hb could also have a different height.

[0048] The fins 100, and therefore the upper fins 100a and lower fins 100b, are distributed along a direction transverse to the extension direction E. In the illustrated example, the direction transverse to the extension direction E corresponds to the transverse direction T.

[0049] There figure 2 represents a rear cross-sectional view in a plane defined by the extension direction and the transverse direction, corresponding in this example respectively to the vertical direction and the transverse direction, of the heat sink 10.

[0050] Each fin 100 has a thickness e in the transverse direction. This thickness e is particularly visible on the figure 2 . This thickness e shows a decrease going from the base 110 of the fin 100 to the free end 111 of the fin 100. In particular, the thickness e of each fin 100 is greater near the base 110 of the fin 100 than near the free end 111 of the fin 100.

[0051] The fins 100 comprise a first portion 101, a second portion 102. In the illustrated example, the fins 100 further comprise a third portion 103. The first portion 101 is located between the base 110 and the second portion 102, the second portion 102 is located between the first portion 101 and the third portion 103, and the third portion 103 is located between the second portion 102 and the free end 111. In each of these portions 101, 102, 103, the variation in thickness e of the fin is different.

[0052] The decrease in thickness e of each fin 100 is greater in the second portion 102 than in the first portion 101. The decrease in thickness e of fin 100 in the third portion 103 is less than the decrease in thickness e of fin 100 in the second portion 102. In the illustrated example, the decrease in thickness e of fin 100 in the third portion 103 is identical to the decrease in thickness e of fin 100 in the first portion 101.

[0053] To illustrate these variations in thickness e of the fins 100, the fins 100 of the heat sink 10 are schematically represented in the figure 3. On each fin 100, we can consider a first part P1 of the first portion 101, a second part P2 of the second portion 102 and a third part P3 of the third portion 103, each of these first, second and third parts P1, P2, P3 having an identical height H, taken along the extension direction E of the fin 100. Each of the first, second and third parts P1, P2, P3 are delimited by an upper end P1sup, P2sup, P3sup turned towards the free end 111 of the fin 100 and a lower end P1inf, P2inf, P3inf turned towards the base 110 of the fin 100. Each upper end P1sup, P2sup, P3sup includes a thickness e1h, e2h, e3h taken in the transverse direction, and each lower end P1inf, P2inf, P3inf includes a thickness e1b, e2b, e3b taken in the transverse direction.

[0054] The decrease in thickness e of each fin 100 greater in the second portion 102 than in the first portion 101 results in the fact that the difference between the thickness e1b of fin 100 at the lower end P1inf of the first part P1 and the thickness e1h of fin 100 at the upper end P1sup of the first part P1 is greater than the difference between the thickness e2b of fin 100 at the lower end P2inf of the second part P2 and the thickness e2h of fin 100 at the upper end P2sup of the second part P2.

[0055] The decrease in the thickness e of the fin 100 in the third portion 103 is less than the decrease in the thickness e of the fin 100 in the second portion 102, which means that the difference between the thickness e2b of the fin 100 at the lower end P2inf of the second part P2 and the thickness e2h of the fin 100 at the upper end P2sup of the second part P2 is less than the difference between the thickness e3b of the fin 100 at the lower end P3inf of the third part P3 and the thickness e3h of the fin 100 at the upper end P3sup of the third part P3.

[0056] And in particular, in the illustrated example, the decrease in thickness e of fin 100 in the third portion 103, identical to the decrease in thickness e of fin 100 in the first portion 101, results in the difference between the thickness e1b of fin 100 at the lower end P1inf of the first part P1 and the thickness e1h of fin 100 at the upper end P1sup of the first part P1 is equal to the difference between the thickness e3b of fin 100 at the lower end P3inf of the third part P3 and the thickness e3h of fin 100 at the upper end P3sup of the third part P3.

[0057] The decrease in thickness e of the fins 100 from their base 110 towards their free end 110 is therefore not constant, which allows for a base 110 wide enough to ensure the passage of the material forming the heat sink 10 into the mold during injection, while reducing the thickness of the fin 100 more significantly in the second portion 102 in order to obtain a thinner fin 100 more rapidly as one approaches the free end 111 of the fin 100. Since the fins 100 become thinner more quickly due to the greater reduction in thickness in the second portion 102, it is possible to position the fins 100 closer to each other at their base 110, because ultimately, the distance between the fins 100 increases more rapidly at the second portion 102.Thus, even if it is possible that the fins 100 radiate heat towards each other at the level of the first portion 101, this radiation phenomenon will then be limited at the level of the second portion 102 and the third portion 103. At the level of the second portion 102 and the third portion 103, convection is favoured and radiation towards the outside of the heat sink is also favoured.

[0058] For each of the first, second, and third portions 101, 102, and 103, the decrease in the thickness e of the fin 100 is constant. Thus, for the first portion, regardless of the first part P1 of height H considered, the difference between the thickness e1b of the fin 100 at the lower end P1inf of the first part P1 and the thickness e1h of the fin 100 at the upper end P1sup of the first part P1 is identical. Similarly, for the second portion 102, regardless of the second part P2 of height H considered, the difference between the thickness e2b of the fin 100 at the lower end P2inf of the second part P2 and the thickness e2h of the fin 100 at the upper end P2sup of the second part P2 is identical.Similarly, for the third portion 103, whatever the third part P3 of height H considered, the difference between the thickness e3b of the fin 100 at the lower end P3inf of the third part P3 and the thickness e3h of the fin 100 at the upper end P3sup of the third part P3 is identical.

[0059] Each fin 100 comprises a first transverse side 120 and a second transverse side 130, opposite the first transverse side 120. In particular, the first and second transverse sides correspond to the edges of the fin 100 taken on a section of the fin 100 by a plane comprising the extension direction E and the transverse direction T, corresponding to the cutting plane of the figure 2 , and to the plane in which the fins 100 are schematically represented at the figure 3 .

[0060] The first transverse side 120 is symmetrical to the second transverse side 130 with respect to an axis of symmetry S parallel to the extension direction.

[0061] The decrease in the thickness e of the fin 100 constant in each of the first, second and third portions 101, 102, 103 results in the fact that the first and second transverse sides 120, 130 are formed by a straight line segment for each of the first, second and third portions. Thus, the first portion 101 includes a first primary draft angle i1 formed between the first transverse side 120 of the fin 100 in the first portion 101 and the extension direction E, the second portion 102 includes a second primary draft angle i2 formed between the first transverse side 120 of the fin 100 in the second portion 102 and the extension direction E, and the third portion 103 includes a third primary draft angle i3 formed between the first transverse side 120 of the fin 100 in the third portion 103 and the extension direction E.

[0062] The first primary draft angle i1 is less than the second primary draft angle i2, and the third primary draft angle i3 is less than the second primary draft angle i2, and in particular, in the illustrated example, the third primary draft angle i3 is identical to the first primary draft angle i1.

[0063] By symmetry, the draft angle along the second transverse side 130 of each fin 100 follows the same evolution as the draft angle along the first transverse side 120 of the fin. In particular, the first portion 101 includes a first secondary draft angle i1' formed between the second transverse side 130 of the fin 100 in the first portion 101 and the extension direction E, the second portion 102 includes a second secondary draft angle i2' formed between the second transverse side 130 of the fin 102 in the second portion 102 and the extension direction, and the third portion 103 includes a third secondary draft angle i3' formed between the second transverse side 130 of the fin in the third portion 103 and the extension direction E.

[0064] The first primary draft angle i1 is identical to the first secondary draft angle i1', the second primary draft angle i2 is identical to the second secondary draft angle i2', and the third primary draft angle i3 is identical to the third secondary draft angle i3'.

[0065] There figure 4 schematically represents an alternative shape of the fins 100 of the heat sink 10. The fins 100 shown on the figure 4 They differ from those shown in the other figures only in that the decrease in thickness e of fin 100 in the first portion 101 and in the second portion 102 is not constant. In the illustrated example, the decrease in thickness e of fins 100 is constant for the third portion 103.

[0066] Only the decrease in the non-constant thickness e in the first portion 101 and the second portion 102 will be explained in the remainder of the description, it being understood that otherwise, the description of the fins 100 made with reference to the figures 1 to 3 applies to the 100 fins of the figure 4 , and in particular, the description made of the third portion 103.

[0067] Since the decrease in thickness e of the fins 100 is not constant, for the first portion 101, the difference between the thickness e1b of fin 100 at the lower end P1inf of the first part P1 and the thickness e1h of fin 100 at the upper end P1sup of the first part P1 varies depending on the specific first part P1 considered. Similarly, for the second portion 102, the difference between the thickness e2b of fin 100 at the lower end P2inf of the second part P2 and the thickness e2h of fin 100 at the upper end P2sup of the second part P2 varies depending on the specific second part P2 considered.

[0068] The non-constant decrease in the thickness e of the fins 100 in the first portion 101 and in the second portion 102 also results in the fact that the first and second transverse sides 120, 130 are formed by a continuous curve for the first and second portions.

[0069] The first portion 101 includes a first primary draft angle i1 formed between the tangent to the first transverse side 120 of the fin 100 in the first portion 101 and the extension direction E; the second portion 102 includes a second primary draft angle i2 formed between the tangent to the first transverse side 120 of the fin 100 in the second portion 102 and the extension direction E. The first primary draft angle i1 and the second primary draft angle i2 vary along the first transverse side 120. In particular, the first primary draft angle i1 and the second primary draft angle i2 increase as the tangent to the first transverse side 120 moves away from the base 11 of the heat sink 10.

[0070] The third primary draft angle i3 is less than the second primary draft angle i2. In particular, the second portion 102 can be defined as a portion in which all the second primary draft angles i2 are less than the third primary draft angle i3. The portion then lying between the second portion 102 thus defined and the base 110 of the fin 100 forms the first portion 101.

[0071] By symmetry, the draft angle along the second transverse side 130 of each fin 100 follows the same evolution as the draft angle along the first transverse side 120 of the fin.

[0072] On the figures 5 and 6 A light module 20 for a motor vehicle is shown, in which the heat sink 10 is mounted. This light module 20 is intended to be mounted in a motor vehicle headlight.

[0073] The light module 20 comprises a plurality of light sources 201 configured to emit a light beam, and a printed circuit board 202 on which the light sources 201 are arranged. The heat sink 10 cools the light sources 201. The printed circuit board 202 rests on the heat sink 10. In this example, the parting line P of the heat sink 10 is parallel to the printed circuit board 202.

[0074] The light module 20 comprises a first optical element in the form of a reflector 203 and a second optical element in the form of a projection lens 204. The reflector 203 is designed to receive the light beam emitted by the light sources 201 and to reflect this light beam towards the projection lens 204. The projection lens 204 allows the light beam reflected by the reflector 203 to be projected onto the road on which the vehicle is traveling.

Claims

1. Heat sink (10) for a light module for a motor vehicle comprising at least one cooling protrusion (100) extending between a base (110) and a free end (111) along an extension direction (E), and having a thickness (e) in a direction transverse to the extension direction (E), the thickness of the cooling protrusion decreasing from the base to the free end, the cooling protrusion (100) comprising a first transverse side (120) and a second transverse side (130), opposite to the first transverse side corresponding to the edges of the cooling protrusion (100) taken on a section of the cooling protrusion by a plane including the extension direction and the transverse direction, and the cooling protrusion (100) comprising a first portion (101), and a second portion (102), the first portion being located between the base and the second portion, and the second portion being located between the first portion and the free end, the decrease in thickness of the cooling protrusion being greater in the second portion than in the first portion, and the first portion (101) comprises a first primary draft angle (i1) formed between the first transverse side (120) of the cooling protrusion (100) in the first portion (101) and the extension direction (E), and the second portion (102) comprises a second primary draft angle (i2) formed between the first transverse side (120) of the cooling protrusion (100) in the second portion (102) and the extension direction (E), and the first primary draft angle (i1) is less than the second primary draft angle (i2) characterized in that the cooling protrusion (100) includes a third portion (103) located between the second portion (102) and the free end (111), the decrease in thickness of the cooling protrusion (100) in the third portion (103) being less than the decrease in thickness of the cooling protrusion (100) in the second portion (102), and the third portion (103) comprises a third primary draft angle (i3) formed between the first transverse side (120) of the cooling protrusion (100) in the third portion (103) and the extension direction (E), the third primary draft angle (i3) being less than the second primary draft angle (i2).

2. Heat sink according to one of the preceding claims comprising a plurality of cooling protrusions (100) along the transverse direction.

3. Heat sink according to claim 1 or 2, wherein the cooling protrusion is formed by a fin (100) or a pin.

4. Heat sink according to one of claims 1 to 3, wherein the decrease in thickness of the cooling protrusion is constant in the first portion (101) and in the second portion (102).

5. Heat sink according to one of the preceding claims, wherein the first transverse side (120) is symmetrical to the second transverse side (130) with respect to an axis of symmetry (S) parallel to the extension direction (E).

6. Heat sink according to one of the preceding claims, comprising at least one upper cooling protrusion (100a) and one lower cooling protrusion (100b), and wherein the upper and lower cooling protrusions are aligned and extend in the same extension direction, in opposite directions.

7. Heat sink according to one of the preceding claims, comprising a joint plane (P) extending in a longitudinal plane, perpendicular to the extension direction.

8. Light module (20) for a motor vehicle comprising a heat sink (10) according to one of the preceding claims.

9. Light module (20) according to the preceding claim further comprising: - at least one light source (201) configured to emit a light beam; - at least one printed circuit board (202) on which the light source is disposed; - at least one optical element (203, 204) configured to deflect and / or project the light beam emitted by the light source; and wherein the heat sink is configured to cool said at least one light source.