Electronic subassembly with improved heat sink mounting

Abstract

An electronic subassembly with improved heat sink mounting has a printed circuit board with a component side. The electronic unit is arranged on the component side and has, on its side remote from the printed circuit board, a cooling surface extending parallel to the printed circuit board. The subassembly has a heat sink placed on a cooling surface of the electronic unit with a contact surface. The subassembly has a clip that overlaps the heat sink on a side of the heat sink remote from the unit and is connected to the printed circuit board. The subassembly has an auxiliary structure made of an electrically insulating material and placed on the component side. The auxiliary structure has a clip receptacle for the clip into which the clip can be introduced before the auxiliary structure is placed on the component side. The auxiliary structure has a heat sink receptacle into which the heat sink can be introduced before the auxiliary structure is placed on the component side, and in which the heat sink is held and guided.

Description

Technical Field

[0001] The present invention starts with the electronic subassembly,

[0002] - wherein the subassembly has a printed circuit board with a component side,

[0003] wherein an electronics unit is arranged on the component side, the electronics unit having a cooling surface extending parallel to the printed circuit board on a side of the electronics unit facing away from the printed circuit board,

[0004] - wherein the subassembly has a heat sink which is placed with a contact surface on a cooling surface of the electronic unit,

[0005] - wherein the subassembly has a clip which overlaps the heat sink on its side facing away from the unit and is connected to the printed circuit board. Background Art

[0006] Such subassemblies are well known. For example, the conventional main board of a PC is implemented in this way. Other subassemblies used in the industrial sector, such as control subassemblies, often have this structure.

[0007] The placement of the heat sink and the clip and the connection of the clip are usually carried out manually. Therefore, the heat sink and the clip are placed on the heat sink one by one by hand. Thereafter, the clip is also connected to the printed circuit board manually.

[0008] The methods of the prior art are mainly disadvantageous because the cooling surface of the electronic unit is usually relatively small. Therefore, it can easily happen that the contact surface of the heat sink is oriented at a certain angle relative to the cooling surface of the electronic unit, so that the contact surface of the heat sink is inclined relative to the cooling surface of the unit. The thermal contact between the electronic unit and the heat sink is thus deteriorated, making it possible to only perform poor cooling of the electronic unit. Therefore, the electronic unit is only cooled insufficiently. The insufficient cooling cannot be improved sufficiently by the thermal paste introduced between the cooling surface and the contact surface. As a result of this situation, the electronic unit can only be operated at a reduced capacity (for example, in the case of a processor, it can only be operated at a reduced clock frequency), or even damage and failure of the electronic unit and thus the electronic subassembly as a whole can occur relatively quickly. Summary of the invention

[0009] The object of the invention is to create a possibility by which a parallel or at least almost parallel orientation of the contact surface of the heat sink relative to the cooling surface of the electronic unit can be achieved relatively easily.

[0010] This object is achieved by an electronic subassembly having the features of the invention. Advantageous embodiments of the electronic subassembly are the subject of the invention.

[0011] According to the invention, an electronic subassembly of the type mentioned in the introduction is embodied as follows:

[0012] - the subassembly has an auxiliary structure made of an electrically insulating material and placed on the component side,

[0013] the auxiliary structure has a clip receptacle for a clip, into which the clip can be introduced before the auxiliary structure is placed on the component side,

[0014] the auxiliary structure has a heat sink receptacle into which the heat sink can be introduced before the auxiliary structure is placed on the component side and in which the heat sink is held and guided,

[0015] the heat sink receiving portion has a retaining hook, by means of which the movement of the heat sink in the direction of the printed circuit board is limited, and

[0016] After the clip has been connected to the printed circuit board, the heat sink is spaced apart from the retaining hooks, or the heat sink is pressed onto the retaining hooks by means of the clip and the auxiliary structure is bent by this pressing.

[0017] The electronic subassembly can in particular be a control unit of an industrial control, for example a programmable control or a digital control or a motion control.

[0018] The subassembly can have a plurality of electronic units, which are cooled by means of corresponding heat sinks. It is important that there is at least one such unit. The electronic unit can be, for example, a processor.

[0019] As is generally the case, the heat sink has cooling ribs on the side of the heat sink facing away from the contact surface. A heat conducting component can be located between the electronic unit and the heat sink, the component previously being applied to the cooling surface or the contact surface. The heat conducting component can be, for example, a thermally conductive paste or a plurality of small thermally conductive pads (PADs). The heat conducting component can also include a phase change material (PCM = phase change material).

[0020] Usually, the electronic unit is soldered to the printed circuit board. However, it is also feasible to plug the electronic unit into a socket, which itself is soldered to the printed circuit board.

[0021] The clip can be connected to the printed circuit board, in particular by means of fixing screws.

[0022] Typically, the material constituting the auxiliary structure is a plastic material, in particular, it can be a thermoplastic.

[0023] The embodiment of the clip receiving part can be as desired. In particular, the clip receiving part can contact the sections of the clip on their sides facing each other and / or on their sides facing away from each other, which sections are oriented substantially perpendicular to the component side when the auxiliary structure is placed on the component side.

[0024] When the heat sink is inserted into the heat sink receptacle, essentially only a linear movement of the heat sink is still possible. This also applies when the auxiliary structure has not yet been placed on the component side. The movement direction corresponds to the direction towards the printed circuit board when the auxiliary structure is placed on the component side.

[0025] A movement of the heat sink in the direction away from the circuit board when the auxiliary structure is placed on the component side is possible only to a small extent. This movement, i.e. the movement away from the retaining hooks, is limited by the clip or by elements of the auxiliary structure.

[0026] In many cases, when the auxiliary structure is placed on the component side, the contact surface of the heat sink comes into contact with the cooling surface of the electronic unit. In this case, the heat sink is lifted from the retaining hooks when the auxiliary structure is placed on the component side. From this point in time, after the clip is connected to the printed circuit board, the heat sink is therefore spaced apart from the retaining hooks. The spacing of such heat sinks from the retaining hooks is usually very small, at most 2 mm. Alternatively, the auxiliary structure can have a weak configuration so that when the clip is connected to the printed circuit board, in combination with the accompanying pressing of the heat sink onto the retaining hooks, the heat sink is lowered onto the retaining hooks again, but the auxiliary structure is bent.

[0027] Preferably, the clip receptacle is embodied such that the clip can be introduced into the clip receptacle from the side of the auxiliary structure which faces the printed circuit board (and only from this side) when the auxiliary structure is placed on the component side. This circumstance simplifies the construction of the auxiliary structure.

[0028] Preferably, when the clip is in the clip receptacle, the clip is securely held in the auxiliary structure even before the heat sink is introduced into the heat sink receptacle and before the auxiliary structure is placed on the component side. This leads in particular to improved reliability during the production of the electronic subassembly. Because when, for example, the auxiliary structure is transported from mounting station A to mounting station B after the clip has been introduced into the clip receptacle, wherein, for example, the heat sink is inserted into the heat sink receptacle, the clip cannot be lost during this transport.

[0029] Preferably, the heat sink receptacle is designed so that the heat sink can be introduced into the heat sink from that side of the auxiliary structure which faces the printed circuit board when the auxiliary structure is placed on the component side (and only from this side). This simplifies the construction of the auxiliary structure.

[0030] Preferably, the auxiliary structure has a spacer which protrudes from the component side of the printed circuit board and protrudes beyond the heat sink in the protruding direction.

[0031] The advantage of this embodiment is that the auxiliary structure can be handled simply when the clip is introduced into the clip receptacle and the heat sink into the heat sink receptacle before the auxiliary structure is placed on the component side. This is because the auxiliary structure can be placed on a flat base (e.g. the surface of a table) so that the auxiliary structure with the spacers stands on the base (so to speak "from the back to the front"). With this positioning and orientation of the auxiliary structure, the clip and the heat sink can then be introduced into the auxiliary structure one after the other from above. After the clip and the heat sink have been introduced into the auxiliary structure, the clip and the heat sink are pre-fixed in the auxiliary structure so that the auxiliary structure together with the clip and the heat sink can be placed on the component side of the printed circuit board.

[0032] Preferably, the auxiliary structure has a stop by which the movement of the heat sink in a direction away from the printed circuit board is limited. Thus, the heat sink can be pre-fixed in the auxiliary structure, in particular independently of the exact positioning of the clip in the auxiliary structure and independently of the configuration of the clip.

[0033] The positioning of the retaining hook and the stop can be matched in particular to the heat sink so that the heat sink can move a maximum of 5 mm in the heat sink receiving part. Generally, in such a connection, the higher the reliability with which the contact surface of the heat sink is oriented parallel (or almost parallel) to the cooling surface of the electronic unit, the less likely the heat sink is to move in the heat sink receiving part. On the other hand, in order to be able to compensate for tolerances, a certain minimum value of movement is usually possible. In many cases, it is sufficient for the heat sink to be able to move less than 5 mm in the heat sink receiving part, for example a maximum of 4 mm, a maximum of 3 mm or a maximum of 2 mm. In some cases, values ​​below 2 mm are feasible, but generally not necessary.

[0034] Preferably, before the auxiliary structure is placed on the component side, when the clip is inserted into the clip receiving portion, the heat sink arranged in the heat sink receiving portion is pressed onto the retaining hook by the clip. Thus, before the auxiliary structure is placed on the component side, a defined position of the clip and the heat sink is obtained in the auxiliary structure.

[0035] Preferably, the auxiliary structure has positioning pins, which are introduced into recesses of the printed circuit board. When the auxiliary structure is placed on the component side, the positioning pins are introduced into the recesses. The positioning pins facilitate the precise positioning of the auxiliary structure.

[0036] Preferably, the auxiliary structure is latched to the printed circuit board via latching hooks overlapping the outer side of the printed circuit board. This type of connection is particularly easy to realize. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above characteristics, features and advantages of the present invention and the manner in which they are achieved will become clearer and easier to understand in the context of the following description of the embodiments explained in more detail in conjunction with the accompanying drawings. A schematic diagram is shown here:

[0038] Figure 1 shows the components of the electronic subassembly from the side,

[0039] Figure 2 Shown from above Figure 1 Components of electronic subassemblies,

[0040] Figure 3 Shows the heat sink and clip from below,

[0041] Figure 4 An electronic subassembly is shown with an auxiliary structure placed on the component side of a printed circuit board,

[0042] Figure 5 The auxiliary structure is shown in a perspective view,

[0043] Figure 6 Shown is a clip with an inserted Figure 5 The auxiliary structure of

[0044] Figure 7 Shown with inserted clip and inserted heat sink Figure 5 The auxiliary structure of

[0045] Figure 8 The front clip is shown.

[0046] Fig. 9 Shown from above Figure 8 The clamp,

[0047] Fig.10 Shown from the side Figure 8 The clamp,

[0048] Fig.11 Shows part of the heat sink, clips and auxiliary structures,

[0049] Fig.12 Shows part of the heat sink, clips and auxiliary structures,

[0050] Fig.13 shows the electronic subassembly, and

[0051] Fig.14 Shown are portions of the heat sink, clips and auxiliary structures. DETAILED DESCRIPTION

[0052] according to Figure 1 and Figure 2, the electronic subassembly has a printed circuit board 1. The printed circuit board 1 has a component side 2. An electronic unit 3 is arranged on the component side 2.

[0053] Typically, a large number of electronic units 3 are arranged on the component side 2. However, in the present case only a single unit marked with reference numeral 3 will be considered in more detail.

[0054] The electronic unit 3 can be, for example, a processor. Independently of the type of unit 3, on its side facing away from the printed circuit board 1, the electronic unit 3 has a cooling surface 4. The cooling surface 4 extends parallel to the printed circuit board 1, more precisely parallel to the component side 2.

[0055] The heat sink 5 of the subassembly is placed together with the contact surface 6 on the cooling surface 4 of the electronic unit 3. Figure 1 The spacing between the contact surface 6 and the cooling surface 4 shown in the figure does not actually exist. A heat conducting component (not shown) can be arranged between the cooling surface 4 and the contact surface 6. The clip 7 overlaps the heat sink 5 on the side facing away from the unit 3 (and the printed circuit board 1). The clip 7 is connected to the printed circuit board 1, for example, by means of schematically shown connecting screws 8. The cooling ribs of the heat sink 5 are Figure 2 , but without providing a reference numeral.

[0056] Figure 3 By way of example, a possible embodiment of the heat sink 5 and the associated cooperation with the clip 7 is shown, seen from the bottom side, ie from the printed circuit board 1 .

[0057] In order to fix the heat sink 5 and the clip 7, according to Figure 4 The electronic subassembly in the embodiment has an auxiliary structure 9. The auxiliary structure 9 is made of an electrically insulating material. Figure 4 As shown by the arrow in , the auxiliary structure is placed on the component side 2. Before placement on the component side 2, the heat sink 5 and the clip 7 are arranged in the auxiliary structure 9. After the auxiliary structure 9 is placed on the component side 2, the clip 7 is connected to the printed circuit board 1 and the contact surface 6 of the heat sink 5 is thus pressed onto the cooling surface 4 of the electronic unit 3 by means of the clip 7.

[0058] The following will first combine Figures 5 to 7 To explain the structural design of the auxiliary structure 9. The auxiliary structure 9 with the heat sink 5 and the clip 7 will also be combined with Figures 5 to 7 Provide explanation.

[0059] From About Figures 5 to 7It can be seen from the subsequent description that the auxiliary structure 9 is configured to receive two heat sinks 5 and two associated clips 7. The auxiliary structure 9 will be explained in conjunction with this specific design below. It is also sufficient if the auxiliary structure 9 is configured to receive only a single heat sink 5 and a single clip 7. Similarly, the auxiliary structure 9 can also be configured to receive more than two heat sinks 5 and correspondingly receive more than two associated clips 7.

[0060] according to Figures 5 to 7 The auxiliary structure 9 has a clip receiving portion 10 for each clip 7. The clip receiving portion 10 matches the clip 7. The clip receiving portion 10 for the corresponding clip 7 matches the clip 7 so that the corresponding clip 7 can be introduced into the corresponding clip receiving portion 10 before the auxiliary structure 9 is placed on the component side 2 of the printed circuit board 1.

[0061] There are many feasibility of the specific design of the clip 7 and the clip receiving portion 10. In this example, for example, according to Figures 8 to 10 The clamp 7 is designed in such a way that it has a pressure region 11 in the central region. Figure 1 and Figure 2 In the mounted state (ie when the clip 7 is connected to the printed circuit board 1), the pressure area 11 is pressed against the upper side of the heat sink 5. The pressure area 11 can in particular be warped or angled so that when the clip 7 is in Figure 8 When descending in the direction indicated by 12, the central area of ​​the pressure area 11 first contacts the heat sink 5, and then the clip 7 bends under the accumulation of compressive force.

[0062] The fixing region 13 adjoins the pressure region 11 on both sides, via which the respective clip 7 is connected to the printed circuit board 1. For example, the fixing region 13 can have a recess 14 for the penetration of the connecting screw 8. The fixing region 13 is connected to the pressure region 11 via a transition section 15. In the mounted state of the respective clip 7, the transition section 15 is oriented substantially orthogonally to the printed circuit board 1, while the pressure region 11 and the fixing region 13 extend substantially parallel to the printed circuit board 1. The end region 16 adjoins the fixing region 13 on the outside. In the mounted state of the respective clip 7, the end region 16 is likewise oriented substantially orthogonally to the printed circuit board 1. The end regions 16 can each have, for example, one elongated hole 17. In this case, the respective clip 7 can be mounted on the auxiliary structure 9 at the ends of the clip by means of two elongated holes 17.

[0063] In the case of a specific design of the clip 7, the auxiliary structure 9 can, for example, have a web 18 as a clip receptacle 10, the faces of which come to rest on the mutually facing sides (alternatively: on the mutually facing sides) of the end region 16 when the clip 7 is inserted into the clip receptacle 10. In this case, the web 18 can, for example, be designed to be slightly elastic and have, for example, projections 19 on the corresponding faces, which are introduced into the corresponding slots when the corresponding clip 7 is inserted into the corresponding clip receptacle 10. Figure 6 The corresponding state of the auxiliary structure 9 is shown.

[0064] according to Figure 6 As shown, the clamps 7 each have a longitudinal recess in the region of the respective pressure region 11. This design of the clamp 7 is preferred, but is of secondary importance in the context of the present invention.

[0065] The side of the auxiliary structure 9 which subsequently (after the auxiliary structure 9 has been placed on the component side 2) faces the component side 2 is located at Figures 5 to 7 The corresponding clip 7 is also introduced from above into the corresponding clip receiving portion 10 (at Figures 5 to 7 ). Thus, when the auxiliary structure is placed on the component side 2, the corresponding clip 7 is inserted into the clip receiving portion 10 from the side of the auxiliary structure 9 facing the printed circuit board 1. This embodiment is preferred.

[0066] Furthermore, the respective clip 7 is securely held in the auxiliary structure 9 due to the projection 19 when the clip is in the respective clip receptacle 10. This applies to the introduction of the respective clip 7 into the respective clip receptacle 10 and, therefore, in particular, also before the introduction of the respective heat sink 5 into the respective heat sink receptacle 20 (to be explained below) and also before the placement of the auxiliary structure 9 on the component side 2.

[0067] according to Figures 5 to 7 The auxiliary structures 9 also respectively have the aforementioned radiator receiving parts 20 for the radiators 5. The radiator receiving parts 20 match the radiators 5. The radiator receiving parts 20 for the respective radiators 5 match the respective radiators 5 so that the respective radiators 5 can be introduced into the respective radiator receiving parts 20 before the auxiliary structures 9 are placed on the component side 2, and the radiators 5 are held and guided in the respective radiator receiving parts 20.

[0068] The heat sink receptacle 20 has, for example in a corner region, retaining hooks 21 . The displacement of the respective heat sink 5 in the direction of the printed circuit board 1 is limited by means of the retaining hooks 21 .

[0069] Therefore, in Figures 5 to 7, the corresponding heat sink 5 is also introduced from above into the corresponding heat sink receptacle 20. Therefore, when the auxiliary structure 9 is placed on the component side 2, the corresponding heat sink 5 is inserted into the corresponding heat sink receptacle 20 from the side of the auxiliary structure 9 facing the printed circuit board 1. This design requires in particular that the corresponding heat sink 5 is introduced into its heat sink receptacle 20 only after the associated clip 7 has been introduced into the corresponding clip receptacle 10.

[0070] The design explained above is preferred. Figure 7 The corresponding state of the auxiliary structure 9 is shown. In this state (i.e., in particular even before the auxiliary structure 9 is placed on the component side 2), the corresponding heat sink 5 is pressed onto the retaining hook 21 by the corresponding clip 7. As previously described, in this connection, the corresponding heat sink 5 is inserted into the corresponding heat sink receptacle 20 and the corresponding clip 7 is also inserted into the corresponding clip receptacle 10. Fig.11 This state is shown in a rather simplified manner.

[0071] After the clip 7 has been introduced into the clip receiving portion 10 and the heat sink 5 has been introduced into the heat sink receiving portion 20, the auxiliary structure 9 is provided. Figure 4 ) is placed on the component side 2 of the printed circuit board 1. During placement, the auxiliary structure 9 is Figures 5 to 7 The upper side of the auxiliary structure 9 faces the component side 2. In order to fix the auxiliary structure 9 to the printed circuit board 1, the auxiliary structure 9 preferably has a Figures 5 to 7 The hook 22 overlaps the printed circuit board at the outer side of the printed circuit board 1. The auxiliary structure 9 cooperates with the support 23 of the auxiliary structure 9 and is locked to the printed circuit board 1 through the hook 22.

[0072] During the placement of the auxiliary structure 9 on the component side 2 (i.e. even before the placement of the auxiliary structure 9 on the component side 2 is completed), the contact surface 6 of the respective heat sink 5 is preferably in contact with the cooling surface 4 of the respective electronic unit 3. When the placement of the auxiliary structure 9 on the component side 2 is completed, the respective heat sink 5 is thus spaced apart from the retaining hooks 21 of the respective heat sink receiving portion 20. Fig.12 The corresponding state is shown in FIG. The cooling ribs of the radiator 5 are Fig.12 In the embodiment of the present invention, the web is not oriented longitudinally but transversely. This fact is of secondary significance in the context of the present invention.

[0073] Preferably, the auxiliary structure 9 (see again Fig.11) has a stopper 24, by means of which the movement of the corresponding heat sink 5 is limited, that is, the corresponding heat sink 5 retreats in the corresponding heat sink receiving portion 20 in a direction away from the printed circuit board 1. The positioning of the retaining hook 21 and the stopper 24 can be particularly matched with the corresponding heat sink 5, so that the corresponding heat sink can move at most 5mm in the corresponding heat sink receiving portion 20.

[0074] The stopper 24 is Fig.11 and Fig.13 21. The design is feasible, but generally not preferred. Figures 5 to 7 Corresponding to the illustration in FIG. 2 , it is preferred that, in the design, the stopper 24 is an independent element, which is arranged next to the retaining hook 21 .

[0075] When the clip 7 is subsequently connected to the printed circuit board 1 , the heat sink 5 is usually lowered slightly onto the printed circuit substrate 1 again. Fig.13 The electronic subassembly is shown after the auxiliary structure 9 has been placed on the component side 2 .

[0076] Typically, after the clip 7 is attached to the printed circuit board 1, the corresponding heat sink 5 is located inside the corresponding heat sink receiving portion 20. Fig.11 and 12 between the two extreme positions shown in Fig.14 Therefore, preferably, after the corresponding clip 7 is connected to the printed circuit board 1, the corresponding heat sink 5 is also spaced apart from the holding hook 21.

[0077] Alternatively and not shown in the figures, the respective heat sink 5 can be pressed again onto the retaining hooks 21 by means of the respective clips 7. In this case, however, the retaining hooks 21 must not prevent the respective heat sink 5 from being pressed onto the associated electronic unit 3. Therefore, in this case, the auxiliary structure 9 must be designed to be telescopic, so that the auxiliary structure 9 bends by pressing the respective heat sink 5 onto the retaining hooks 21, i.e. the auxiliary structure 9 yields.

[0078] In order to simply assemble the auxiliary structure 9, according to Figures 5 to 7 The auxiliary structure 9 preferably has a spacer 25. In the mounted state, the spacer 25 protrudes from the component side 2 of the printed circuit board 1. Typically, the spacer 25 is arranged at least in the region of the corners of the auxiliary structure 9. Furthermore, the spacer 25 protrudes over the heat sink 5 (or in the case of a plurality of heat sinks 5, over the heat sink 5) in the direction (i.e. away from the component side 2 of the printed circuit board 1). Thus, as Figures 5 to 7 As shown, the auxiliary structure 9 with the spacers 25 can be placed on a surface of a table or the like and equipped with the clips 7 and the heat sink 5 without any problems.

[0079] In order to easily position the auxiliary structure 9 when placing it on the component side 2, according to Figures 5 to 7 The auxiliary structure 9 can also have positioning pins 26. The positioning pins 26 are introduced into corresponding recesses (not shown) of the printed circuit board 1 in this case. Therefore, it is guaranteed that the lateral positioning of the auxiliary structure 9 relative to the printed circuit board 1 is correct.

[0080] In summary, the present invention therefore relates to the following facts:

[0081] The electronic subassembly has a printed circuit board 1 with a component side 2. An electronic unit 3 is arranged on the component side 2, which has a cooling surface 4 extending parallel to the printed circuit board 1 on the side of the electronic unit facing away from the printed circuit board 1. The subassembly has a heat sink 5, which is placed on the cooling surface 4 of the electronic unit 3 with a contact surface 6. The subassembly has a clip 7, which overlaps the heat sink 5 on the side of the heat sink facing away from the unit 3 and is connected to the printed circuit board 1. The subassembly has an auxiliary structure 9, which is made of an electrically insulating material and is placed on the component side 2. The auxiliary structure 9 has a clip receptacle 10 for the clip 7, into which the clip 7 can be introduced before the auxiliary structure 9 is placed on the component side 2. The auxiliary structure 9 has a heat sink receptacle 20, into which the heat sink 5 can be introduced before the auxiliary structure 9 is placed on the component side 2, and the heat sink 5 is held and guided in the heat sink receptacle. The heat sink receiving portion 20 has a retaining hook 21, by means of which the movement of the heat sink 5 in the direction toward the printed circuit board 1 is limited. After the clip 7 is connected to the printed circuit board 1, the heat sink 5 is spaced apart from the retaining hook 21 or the heat sink 5 is pressed onto the retaining hook 21 by means of the clip 7, and the auxiliary structure 9 is bent by this pressing.

[0082] The invention has many advantages. The mounting of the heat sink 5 on the electronic unit 3 is simpler and more reliable. The heat dissipation is reliable. In particular, a very good orientation of the contact surface 6 relative to the cooling surface 4 is achieved by the spacing of the retaining hooks 21 and the stop 24, which spacing significantly exceeds the dimensions of the cooling surface 4 and the contact surface 6, as seen in the plane defined by the printed circuit board 1. The heat sink receptacle 20 also holds the heat sink 5 in its position when the connecting screws 8 are tightened, and tilting of the heat sink 5 is completely or at least almost completely prevented. The mounting can even be automated.

[0083] Although the present invention has been illustrated and described in more detail through the preferred embodiments, the present invention is not limited to the disclosed embodiments and those skilled in the art can derive other variations therefrom without departing from the scope of the present invention.

Claims

1. An electronic subassembly, in, The subassembly comprises a printed circuit board (1) with a component side (2), wherein an electronic unit (3) is arranged on the component side (2), the electronic unit having a cooling surface (4) extending parallel to the printed circuit board (1) on a side of the electronic unit remote from the printed circuit board (1), The subassembly comprises a heat sink (5) which is placed on a cooling surface (4) of the electronic unit (3) with a contact surface (6). The subassembly comprises a clip (7), the clip overlaps the heat sink (5) at a side of the heat sink away from the electronic unit (3) and the clip is connected to the printed circuit board (1), It is characterized in that The subassembly has an auxiliary structure (9) made of an electrically insulating material and the auxiliary structure is placed on the component side (2), The auxiliary structure (9) has a clip receptacle (10) for the clip (7), into which the clip (7) can be introduced before the auxiliary structure (9) is placed on the component side (2), The auxiliary structure (9) has a radiator receptacle (20) into which the radiator (5) can be introduced and in which the radiator (5) is held and guided before the auxiliary structure (9) is placed on the component side (2), The heat sink receiving portion (20) has a retaining hook (21), by means of which the movement of the heat sink (5) in the direction toward the printed circuit board (1) is limited; and After the clip (7) is connected to the printed circuit board (1), the heat sink (5) is spaced apart from the retaining hook (21), or the heat sink (5) is pressed onto the retaining hook (21) by means of the clip (7) and the auxiliary structure (9) is bent by the pressing.

2. The electronic subassembly according to claim 1, It is characterized in that The clip receptacle (10) is configured such that, when the auxiliary structure (9) is placed on the component side (2), the clip (7) can be introduced into the clip receptacle (10) from the side of the auxiliary structure (9) facing the printed circuit board (1).

3. The electronic subassembly according to claim 1 or 2, It is characterized in that When the clip (7) is located in the clip receptacle (10), the clip is securely held in the auxiliary structure (9) even before the heat sink (5) is introduced into the heat sink receptacle (20) and before the auxiliary structure (9) is placed on the component side (2).

4. An electronic subassembly according to claim 1, 2 or 3, It is characterized in that The heat sink receiving portion (20) is configured such that when the auxiliary structure (9) is placed on the component side (2), the heat sink (5) can be introduced into the heat sink receiving portion (20) from a side of the auxiliary structure (9) facing the printed circuit board (1).

5. An electronic subassembly according to any one of the preceding claims, It is characterized in that The auxiliary structure (9) has a spacer (25) which protrudes from the component side (2) of the printed circuit board (1) and protrudes beyond the heat sink (5) in a protruding direction.

6. An electronic subassembly according to any one of the preceding claims, It is characterized in that The auxiliary structure (9) has a stopper (24), by means of which the movement of the heat sink (5) in a direction away from the printed circuit board (1) is limited.

7. The electronic subassembly according to claim 6, It is characterized in that The positioning of the retaining hook (21) and the stopper (24) matches the heat sink (5) so that the heat sink (5) can move a maximum of 5 mm in the heat sink receiving portion (20).

8. An electronic subassembly according to any one of the preceding claims, It is characterized in that Before placing the auxiliary structure (9) on the component side (2), when the clip (7) is inserted into the clip receptacle (10), the heat sink (5) arranged in the heat sink receptacle (20) is pressed onto the retaining hook (21) by the clip (7).

9. An electronic subassembly according to any one of the preceding claims, It is characterized in that The auxiliary structure (9) has a positioning pin (26) which is introduced into a recess in the printed circuit board.

10. An electronic subassembly according to any one of the preceding claims, It is characterized in that The auxiliary structure (9) is locked to the printed circuit board (1) via a hook (22) overlapping the outer side of the printed circuit board (1).

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