Device for dissipating heat from an electronic component of a motor vehicle, and method for producing the device

Abstract

The invention relates to a device for dissipating heat from an electronic component (26) of a motor vehicle and to a method for producing said device, the device comprising: at least one heat-conducting element (12) having at least one attachment face (16) designed such that heat can be dissipated, via the attachment face (16), from the electronic component (26) arranged on a circuit board (24), wherein a desired gap (x) is formed between the attachment face (16) of the heat-conducting element (12) and the surface of the electronic component (26), and a thermally conductive material (28) is arranged in said gap; and at least one housing (18) which at least partly encloses the circuit board (24), wherein the housing (18) has at least one housing opening (19), at least a part of the heat-conducting element (12) projects out of said housing opening (19), at least one fastening (32, 14, 37) is provided which durably connects the heat-conducting element (12) to the housing (18) with the desired gap (x), and at least one fixing means (33, 34) is provided for fixing the heat-conducting element (12) relative to the housing (18) with the desired gap (x) for the purposes of implementing the durable fastening (14, 32, 37).

Description

[0001] Description

[0002] title

[0003] Device for cooling an electronic component of a motor vehicle and method for producing the device

[0004] The invention relates to a device for cooling an electronic component of a motor vehicle and a method for producing the device according to the preamble of the independent claims.

[0005] State of the art

[0006] DE 102013206999 A1 discloses a control unit for a motor vehicle with a heat-conducting housing wall formed from a heat-conducting sheet metal and forming a heat sink. The heat-conducting housing wall is detachably connected to the housing and has an embossing in a region opposite the power semiconductor. The embossing brings the housing wall closer to the power semiconductor, so that a distance, in particular a gap dimension, between the housing wall and the power semiconductor before embossing is greater than a distance, in particular a distance between the housing wall and the surface area, after embossing.

[0007] The invention is based on the object of ensuring reliable heat dissipation of the electronic component. This object is achieved by the features of the independent claims.

[0008] Disclosure of the invention

[0009] By providing a fixing device for securing the heat-conducting element relative to the housing at the desired gap, the permanent attachment between the heat-conducting element and the housing can be reliably established in the desired position. This ensures sufficiently reliable fixation during the manufacturing process to compensate for movements or vibrations in the line until the end of production. The fixation also ensures that the permanent attachment does not lead to a change in the desired gap, especially if, for example, a screw connection of the permanent attachment presses the heat-conducting element against the housing.

[0010] In a practical development, the fixing device is designed to allow adjustment to different gap sizes. This increases flexibility for different applications.

[0011] In a useful further development, the fixing means is designed as a spacer, in particular as a locking screw and / or as a fastening means in cooperation with an elongated hole on the heat-conducting element or on the housing, in particular as an elongated hole extending along a mounting direction of the heat-conducting element and / or via a holding device influencing the relative movement of the heat-conducting element to the housing and / or via a curable fastening means. If the fixing means is designed as a locking or spacer screw, these can be inserted through through holes in the heat-conducting element and screwed into the housing. These then press the heat-conducting element onto the tips of the locking screws or spacer screws, resulting in a closed force path for permanent fastening, for example in the form of screw connections.When using elongated holes in conjunction with fastenings that protrude through them, the heat-conducting element can be connected to the housing in any position.

[0012] In a practical development, a connection, in particular a tab, is provided between the heat-conducting element and the housing. This allows any additional forces that may still be acting, such as transverse forces, to be absorbed, which further increases the stability of the connection. In a practical development, it is provided that the heat-conducting element has at least one projection that at least partially covers the opening in the housing, with at least one seal and / or the fixing means and / or the fastening means being arranged between the projection and the housing. This reliably protects the interior of the housing from environmental influences. The projection can be used to introduce the fixing means and / or the fastening means, which facilitates assembly.

[0013] Furthermore, a method for producing a device for cooling an electronic component of a motor vehicle is proposed, in which the housing with the printed circuit board, on which at least one electronic component to be cooled is arranged, and the heat-conducting element are provided, wherein the thermally conductive material is applied to the connection surface of the heat-conducting element and / or to the electronic component, the heat-conducting element is introduced into the housing opening, the connection surface of the heat-conducting element is moved relative to the electronic component until the desired gap is established between the connection surface and a surface of the electronic component, wherein the heat-conducting element is fixed relative to the housing so that the desired gap is maintained in order to carry out the permanent attachment of the heat-conducting element to the housing.This manufacturing process ensures reliable attachment of the heat-conducting element to the housing.

[0014] In a practical development, the desired gap is achieved when a maximum force is reached, which acts as a counterforce on a device moving the heat-conducting element relative to the housing. Corresponding forces can be easily measured and, depending on the flexural rigidity of the circuit board, the type of thermally conductive material, etc., provide reliable correlations to the resulting desired gap without having to measure it directly. It is particularly expedient for this purpose that the connection surface of the heat-conducting element is moved relative to the electronic component in a force-controlled and / or displacement-controlled and / or speed-controlled manner until the desired gap is achieved.In a suitable further development, a particularly curable adhesive, in particular a UV-curable adhesive, and / or a fastening means, in particular a screw connection or a rivet connection, or a material-to-material connection, in particular welding, is used as the permanent fastening. The appropriate permanent fastening method can be selected depending on the application, requirements, or geometry.

[0015] Further useful developments arise from further dependent claims and from the description.

[0016] Short description of the drawing

[0017] They show:

[0018] Figure 1 shows steps 1 and 2 in the pre-assembly of a control unit,

[0019] Figure 2 Step 3 in the pre-assembly of a control unit,

[0020] Figure 3 shows steps 4 and 5 in the pre-assembly of a control unit,

[0021] Figure 4 Step 6, in which thermally conductive material is applied to a thermally conductive element,

[0022] Figure 5 Step 7, where the heat-conducting element is rotated,

[0023] Figure 6 Step 8, in which the heat-conducting element is inserted into an opening in the housing of the control unit,

[0024] Figure 7 Step 9 a measure for fixing the heat-conducting element in the desired position,

[0025] Figure 8 Step 10 for fastening the heat-conducting element to the housing in the desired position, Figure 9 an alternative embodiment with lateral screwing or riveting in steps 9 and 10 and

[0026] Figure 10 shows another alternative embodiment with a welded joint in steps 9 and 10.

[0027] Embodiment of the invention

[0028] The invention is illustrated schematically using an embodiment and is described in detail below with reference to the drawing.

[0029] Figure 1 shows a control unit 10 in a side view as a section. At least one electronic component 26 to be cooled is arranged on a printed circuit board 24. For example, further electronic components 26 to be cooled can also be arranged on the printed circuit board 24. For example, a further printed circuit board 24 is provided which is arranged parallel to the other printed circuit board 24 and which carries at least one electronic component 26 to be cooled. The electronic component 26 can be, for example, a so-called SIP (System-In-Place) or a component thereof and / or a so-called System-On-Chip SOC or another semiconductor or electronic component with high power dissipation. A connector 42 is arranged on the side of the printed circuit board 24.

[0030] The printed circuit board 24 can be at least partially enclosed by a housing 18. For this purpose, the printed circuit board 24 can be connected to the housing 18 via fastening means 14 such as screws or the like. The housing 18 has at least one opening 19. A heat-conducting element 12 is subsequently at least partially received in this opening 19. The heat-conducting element 12 protrudes slightly outwards, beyond the surface of the housing 18, thus enabling particularly good heat dissipation. The housing 18 can be, for example, a die-cast housing, but also a sheet metal housing or a plastic housing, etc. Figures 1-3 show the five steps of pre-assembly. In step 1, the printed circuit board 24 populated with electronic components 26 to be cooled is prepared.In the exemplary embodiment, there is another circuit board 24 on the one base circuit board 24 with electronic components 26 to be cooled via the heat-conducting element 12. However, this configuration is shown only as an example.

[0031] In step 2, optionally thermally conductive material 28 is applied to specific locations on the inside of the housing 18. The corresponding locations on the housing 18 are matched to the respective component height of at least one electronic component 26 to be cooled, which can be cooled via the housing 18. The thermally conductive material 28 can, for example, be applied in liquid form. Alternatively, a flexible but solid thermally conductive material 28 (for example a cushion or pad) could also be applied. The housing 18 is preferably made of a thermally conductive material in order to dissipate the heat from the electronic components 26 to be cooled via the housing 18 to the environment and / or via the housing 18 to a thermally conductive element 12 or cooler.

[0032] In step 3 according to Figure 2, the printed circuit board 24 is placed in the housing 18. If necessary, centering pins can ensure the correct position of the printed circuit board 24 relative to the housing 18. Typically, the printed circuit board 24 is pressed against the housing 18 or any screw bosses that serve to accommodate the fastening elements 14, such as screws, until it stops. In this process, the electronic components 26 to be cooled via the housing 18 press the already applied thermally conductive material 28 together to a previously calculated gap, which depends significantly on the tolerances of the interacting electronic components 26 and the housing 18.

[0033] In step 4 (see Figure 3), a cover 25 is mounted for the housing 18. The cover 25 can be centered via the housing 18 or a housing edge, or via a centering pin on the housing 18 or similar. Step 5 completes the process by the fasteners 14 pressing and securing the cover 25 of the housing 18 and the circuit board 24 against the housing 18. The fasteners 14 are screwed, for example, into corresponding receptacles in the housing 18 that protrude into the interior of the control unit 10. This completes the standard pre-assembly process according to steps 1-5.

[0034] The housing 18 has a large opening 19 above at least one electronic component 26 that requires special cooling and is to be cooled via the heat-conducting element 12 or the cooler. For example, further electronic components 26 that are to be cooled via the heat-conducting element 12 can be provided. In the exemplary embodiment, these are arranged on the additional circuit board 24, for example. However, the provision of a single circuit board 24 on which the electronic component 26 is arranged is also possible. Such electronic components 26 that become particularly hot and require special cooling via the heat-conducting element 12 can be so-called SoCs (System-on-Chip) or SIPs (System-in-Place) or other high-performance components.

[0035] The thermally conductive element 12 shown in Figure 4 serves to dissipate heat from at least one electronic component 26. To minimize thermal contact resistance, the electronic component 26 is thermally coupled to the thermally conductive element 12 via a thermally conductive material 28 (to be applied in step 6). The thermally conductive material 28 is arranged between the electronic component 26 and a connection surface 16 on the thermally conductive element 12. The thermally conductive element 12 can be part of a cooler, for example, with appropriately provided cooling fins or with a connection to a water cooler. In any case, the thermally conductive element 12 serves as a heat sink for dissipating heat from the electronic component 26. The thermally conductive element 12 acts as a heat spreader, so that individual, particularly hot spots on the electronic component 26 must be spread across the surface as quickly as possible to prevent thermal overload.Such heat-conducting elements 12, or coolers or heat spreaders, are particularly preferably made of aluminum or pure aluminum, copper (for example, in the form of a copper block), or are designed as a vapor chamber (effective heat dissipation by changing the state of aggregation of the heat transfer medium provided in the vapor chamber) or similar. For particularly effective heat dissipation, it is advantageous to provide the housing opening 19 above the electronic component 26 to be cooled, for particularly effective heat dissipation without the provision of an additional thermally conductive layer.

[0036] Thermally conductive material 28 (TIM: thermal interface materials) can include, for example, thermally conductive pastes, flexible materials in the form of a cushion or pad, etc. A gap x (so-called TIM gap) to be minimized is formed between the connection surface 16 and the surface of the electronic component 26 to be cooled. The smaller this gap x is, the better the power loss of the electronic component 26 can be dissipated. With an active adjustment of the TIM gap, as described in more detail below, the tolerance (for example, of the electronic component 26 and / or the thermally conductive element 12) is ignored and adjusted by measuring the gap. This leads to reproducibly small gaps x, which significantly improves the thermal contact resistance while maintaining the same quality of the thermally conductive material 28.Another advantage is that the applied quantity of thermally conductive material 28 remains constant and does not have to be designed for a maximum gap. Furthermore, tolerances for the housing 18, circuit board 24, electronic component 26 to be cooled, or other components can be made larger, which has a positive effect on manufacturability and price.

[0037] After assembly, the opening 19 of the housing 18 is at least partially covered by a lateral projection 13 of the heat-conducting element 12. The projection 13 can be, for example, a flange, a thinner edge area, or the like.

[0038] According to Figure 4, step 6 follows in the manufacturing process of the control unit 10. On the heat-conducting element 12 or the cooler, the thermally conductive material 28 is applied to a connection surface 16 of the heat-conducting element 12. Furthermore, the heat-conducting element 12 contains at least one, optionally several, spacers 34. The spacers 34 are designed, for example, as screws. The spacers 34 are arranged, for example, in the edge region or in the projection 13 of the heat-conducting element 12. This edge region of the heat-conducting element 12 covers the opening 19 in the housing 18 after assembly. The spacer(s) 34 can be attached or screwed in in step 6. Alternatively, the heat-conducting element 12 could be delivered pre-assembled with the spacers 34. In addition, a seal 30 is arranged or applied to the heat-conducting element 12 or to the projection 13, or dispensed if necessary.The seal 30 is arranged in such a way that the inside of the housing 18 is sealed. The seal 30 can be flexible and / or liquid or pasty and can harden during the manufacturing process. For example, the seal 30 could be designed as an EMC seal for electromagnetic shielding of the interior of the housing 18. The seal 30 can be made, for example, of FIPG (FIGP: Form in Place Gasket (liquid during assembly)), CIPG (Cured in Place Gasket (cured during assembly), FoF Fabric over Foam (fabric tube over foam core), tape, foam core, springs, etc.) and can be inserted or arranged between the heat-conducting element 12 and the housing 18 in order to fully shield or seal the housing 18 electrically. The seal 30 is preferably arranged as a circumferential seal around the part of the heat-conducting element 12 that protrudes into the interior of the housing 18, in particular in the edge region.The seal 30 can be an O-ring, for example. Alternatively, a curable seal 30 could be applied in step 6.

[0039] In step 7, the heat-conducting element 12 with applied thermally conductive material 28, seal 30, and spacer 34 is rotated as indicated by an arrow in Figure 5. The rotated heat-conducting element 12 is then inserted into the opening 19 of the housing 18.

[0040] In step 8 (see Figure 6), the heat-conducting element 12 is pressed into the housing 18 via a device (not specifically shown) (for generating a relative movement of the heat-conducting element 12 and the housing 18). To do this, the device presses the heat-conducting element 12 via the applied heat-conducting material 28, the surface of which onto the surfaces of the respective electronic components 26 to be cooled, with a defined force in the direction of the circuit board 24. This device consists of a linear unit which can determine and control the path S and the force F, as indicated in the adjacent diagram in Figure 6. If necessary, the device can generate a relative movement of the heat-conducting element 12 relative to the housing 18 in a force-controlled and / or path-controlled and / or speed-controlled manner, so that the desired gap x is established.The thermally conductive element 12 is then moved at a low speed against the electronic component 26 to be cooled (via the thermally conductive material 28) until the desired maximum force is reached. By inferring from the material data of the thermally conductive material 28 and the flexural rigidity of the circuit board 24 on which the electronic component 26 to be cooled is arranged, together with the joining speed, the desired minimum gap x (between the connection surface 16 of the thermally conductive element 12 and the surface of the electronic component 26, which is filled with the flexible thermally conductive material 28) can now be generated using the desired maximum force.

[0041] Once the desired minimum gap x has been reached, the device or linear unit stops the joining movement and remains in this position. In this position, the desired gap x has been created between the housing 18 and the heat-conducting element 12, in particular between the underside of the edge region of the heat-conducting element 12 and the top side of the housing 18. This desired gap x depends on the tolerance conditions of the heat-conducting element 12 as well as the electronic component(s) 26 and the bending of the circuit board 24. This desired and now occurring gap x must now be fixed. The goal is to achieve permanent fastening of the heat-conducting element 12 to the housing 18 in this special position, in which the desired minimum gap x has been set via the force- or displacement-controlled device.

[0042] There are various possible solutions for the precise positional fixation of the heat-conducting element 12 relative to the housing 18 using appropriate fixing means. For example, a curable fastening such as a curable adhesive, in particular a UV adhesive, could be used as the fixing means. Furthermore, it is possible to use spacers 34, for example in the form of spacer screws or counterscrews, as the fixing means, as explained in more detail in Figures 4-8. Alternatively, the fixation could also be achieved via lateral fastening or screws or rivets as possible fixing means, as shown by way of example in Figure 9. Alternatively, another fixing method such as welding or the like could be used to permanently fasten the heat-conducting element 12 to the housing 18 (see Figure 10). Further alternatives are conceivable.

[0043] In general, the fixation by the fixing means 14, 33, 34 must meet the following requirements. The fixation must sufficiently secure the heat-conducting element 12 during the manufacturing process to absorb movements or vibrations in the production line until the end of production. The permanent fastening 14, 32, 37 must also be able to permanently dissipate the vibration, shock, or drop loads of the heat-conducting element 12 or cooler into the housing 18, particularly when used in the automotive sector. Furthermore, the solution must be cost-effective, robust, and resistant to potential environmental influences.

[0044] The use of spacers 34, for example in the form of spacer screws or counterscrews, is described in more detail in step 9 as shown in Figure 7. The spacers 34 are used to fix the gap between the heat-conducting element 12, in particular the edge region, and the housing 18, as it has been set with the desired setting of the minimum gap x, for the later final fastening. In this case, for example, the spacers 34 designed as spacer screws in the heat-conducting element 12 can be rotated towards the housing 18 until they or their tip 31 touch the housing 18 (compare the right-hand detailed view of Figure 7). For this purpose, an appropriate torque control with a low limit value for screwing in the spacers 34 could be used.

[0045] Now, conventional fastening means 14 such as screws are inserted through through holes in the heat-conducting element 12 or cooler and screwed into the housing 18 (compare step 10 as shown in Figure 8). These fastening means 14 now press the heat-conducting element 12 onto the tips 31 of the spacers 34 designed as spacer screws, thus providing a closed force path. Thus, the heat-conducting element 12 rests on the housing 18 via the spacers 34 and is pulled through them by the fastening means 14. In the exemplary embodiment, a screw connection is selected as the fastening means 14; alternative fastening means 14 are possible, which in any case ensure permanent fastening of the heat-conducting element 12 in the housing 18 at the desired gap x. The desired gap x is thus permanently secured via the fastening means 14, and the manufacturing process for the control unit 10 is completed.

[0046] The alternative embodiment for fastening the heat-conducting element 12 in the housing 18 according to Figure 9 is characterized by a fixation or fastening transversely to the joining direction of the heat-conducting element 12 in the housing 18. For this purpose, fastening webs can be provided on the housing 18, which are arranged laterally from at least one edge region or projection 13 of the heat-conducting element 12. These fastening webs of the housing 18 are designed such that corresponding fastening means 14 can be brought transversely to the joining direction both through the housing 18 and through the heat-conducting element 12. The fastening webs of the housing 18 comprise, for example, elongated holes 33 for fastening in a precise position and to compensate for tolerances of the heat-conducting element 12, the electronic component 26, and the deflection of the printed circuit board 24. The elongated holes 33 are oriented parallel to the joining direction of the heat-conducting element 12.Alternatively, the elongated holes 33 could also be arranged in the heat-conducting element 12, in particular on the projection 13, with corresponding threads or receptacles on the housing 18 for receiving the fastening means 14. This allows the heat-conducting element 12 and the housing 18 to be connected to one another in different positions.

[0047] For example, to absorb transverse forces, additional connecting means 35 can be provided between the housing 18 and the heat-conducting element 12. For example, the connecting means 35 could be designed as a tab, in particular as an elastic tab. Rivets or other positive-locking geometries can also be used with this type of connection 14.

[0048] As a further alternative embodiment according to Figure 10, a material-to-material connection 37 can be provided for permanent fastening. Thus, the connecting elements 35 could slide along one another during assembly, as shown in Figure 9, and be connected to one another by locally melting them. Here, all common methods are conceivable, such as welding, in particular welding using tongs, laser welding, or the like.

[0049] As an alternative permanent fastening, the fastening 32 could be designed as an adhesive, in particular as an adhesive curable by UV rays. Using these sealing / fastening options, the heat-conducting element 12 can be joined from above through the opening 19 of the housing 18 onto the surface of the electronic component 26 to be cooled and fastened to the housing. The liquid or flexible fastening 32 then cures. For example, a UV adhesive is used as the fastening 32. The adhesive or fastening 32 is irradiated or flashed using UV light and hardens in the process. After the seal 30 and / or the fastening 32 have cured, the heat-conducting element 12 is rigidly connected to the control unit 10 and can dissipate any forces that occur, for example vibration or handling, to the housing 18. This protects solder joints from stress.At the same time, due to the seal 30, an EMC-tight connection is established between the housing 18 and the electrically conductive heat-conducting element 12, which may be necessary.

[0050] The electronic components 26 comprise, in particular, high-performance computer cores that perform particularly computationally intensive functions in the motor vehicle. These can include, for example, autonomous or semi-autonomous driving functions, infotainment, communication interfaces between different bus systems (Ethernet, CAN, LIN, etc.) or gateway functionalities, certain security applications for granting authorization, for example, to access the motor vehicle from outside, or other operations in the motor vehicle associated with particularly high computing power. The electronic components 26 are particularly preferably high-performance processors, multi-core processors, or highly integrated circuits (SoC, System-on-Chip), which are characterized by high power losses. The electronic components 26 arranged on the circuit board 24 are particularly preferably designed to be functionally redundant.If one electronic component 26 fails, the other electronic component 26 can take over the functionality of the failing electronic component 26.

Claims

Claims 1. Device for cooling an electronic component (26) of a motor vehicle, comprising at least one heat-conducting element (12) with at least one connection surface (16) which is designed such that the electronic component (26) arranged on a printed circuit board (24) can be cooled via the connection surface (16), wherein a desired gap (x) is formed between the connection surface (16) of the heat-conducting element (12) and the surface of the electronic component (26), in which gap a thermally conductive material (28) is arranged, comprising at least one housing (18) which at least partially encloses the printed circuit board (24), wherein the housing (18) has at least one housing opening (19), wherein at least a part of the heat-conducting element (12) protrudes from this housing opening (19), wherein at least one fastening (32, 14, 37) is provided which, at the desired gap (x), heat-conducting element (12) permanently connects to the housing (18),wherein at least one fixing means (33, 34) is provided for fixing the heat-conducting element (12) relative to the housing (18) at the desired gap dimension (x) in order to carry out the permanent fastening (14, 32, 37).

2. Device according to claim 1, characterized in that the fixing means (33, 34) is designed to enable adaptation to different gap dimensions (x).

3. Device according to one of the preceding claims, characterized in that the fixing means (14, 33, 34) is designed as a spacer (34), in particular as a locking screw, and / or that the fixing means (14, 33, 34) is designed as a fastening (14) in cooperation with an elongated hole (33) on the heat-conducting element (12) and / or on the housing (18), in particular as an elongated hole (33) extending along a mounting direction of the heat-conducting element (12), and / or that the fixing means (14, 33, 34) is designed via a the relative movement of the heat-conducting element (12) to the housing (18) influencing holding device and / or by a particularly hardenable fastening (32).

4. Device according to one of the preceding claims, characterized in that a connection (35) for absorbing further relative forces, in particular a tab, is provided between the heat-conducting element (12) and the housing (18).

5. Device according to one of the preceding claims, characterized in that the heat-conducting element (12) has at least one projection (13) which at least partially covers the opening (19) of the housing (18), wherein at least one seal (30) and / or the fixing means (13, 33, 34) and / or the fastening (14, 32, 37) is / are arranged between the projection (13) and the housing (18).

6. A method for producing a device for cooling an electronic component (26) of a motor vehicle, wherein the device comprises at least one heat-conducting element (12) with at least one connection surface (16), wherein the connection surface (16) is designed such that the electronic component (26) arranged on at least one printed circuit board (24) can be cooled via the connection surface (16), wherein a desired gap (x) is formed between the connection surface (16) of the heat-conducting element (12) and the surface of the electronic component (26), wherein a thermally conductive material (28) is arranged between the connection surface (16) of the heat-conducting element (12) and the surface of the electronic component (26), comprising at least one housing (18) which at least partially encloses the printed circuit board (24), wherein the housing (18) has at least one housing opening (19), wherein at least one fastening (32, 14, 37) is provided,which permanently connects the heat-conducting element (12) to the housing (18) at the desired gap size (x), with the following steps: Providing the housing (18) with the printed circuit board (24) on which at least one electronic component (26) to be cooled is arranged, Providing the heat-conducting element (12), Applying the thermally conductive material (28) to the connection surface (16) of the heat-conducting element (12) and / or to the electronic component (26), Inserting the heat-conducting element (12) into the housing opening (19), Moving the connection, connection surface (16) of the heat-conducting element (12) relative to the electronic component (26) until the desired gap dimension (x) is established between the connection surface (16) and a surface of the electronic component (26), fixing the heat-conducting element (12) relative to the housing (18) so that the desired gap dimension (x) is maintained in order to carry out the permanent fastening (14, 32, 37) of the heat-conducting element (12) to the housing (18).

7. Method according to the preceding method claim, characterized in that the desired gap dimension (x) is established when a maximum force is reached which acts as a counterforce on a device moving the heat-conducting element (12) relative to the housing (18).

8. Method according to one of the preceding method claims, characterized in that the connecting surface (16) of the heat-conducting element (12) is moved relative to the electronic component (26) in a force-controlled manner and / or in a path-controlled manner and / or in a speed-controlled manner until the desired gap dimension (x) between the connecting surface (16) and the electronic component (26) is established.

9. Method according to one of the preceding method claims, characterized in that the maximum force depends on a rigidity of the circuit board (24) and / or the thermally conductive material (28) between the connection surface (16) and the surface of the electronic component (26) and / or on a joining speed with which the thermally conductive element (12) is moved relative to the housing (18).

10. Method according to one of the preceding method claims, characterized in that when the desired gap dimension (x) is reached, a spacer (34), in particular a locking screw, is moved or screwed in until a tip of the spacer (34) touches a counter surface, in particular on the housing (18), in order to fix the desired gap dimension (x). 11 . Method according to one of the preceding method claims, characterized in that when the desired gap dimension (x) is reached, the fastening (14) is brought through an elongated hole (33) and fixed and / or permanently fastened.

12. Method according to one of the preceding method claims, characterized in that a particularly curable adhesive (32), in particular an adhesive curable by UV light (34), and / or a fastening means (14), in particular a screw connection (14) and / or a rivet connection, or a material connection (37), in particular welding, is used as the permanent fastening.

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