Electronic device allowing optimized cooling of electronic components

Abstract

The invention relates to an electronic device comprising: - a printed circuit (2); - an electronic component (3) assembled on the printed circuit (2); - a cooling device (4) assembled to the printed circuit (2), the cooling device (4) comprising a cooling face (40) facing the electronic component (3); - a mounting system comprising: o a positioning device (5) assembled to the cooling device (4), the positioning device being configured to adjust the distance between an upper face (30) of the electronic component (3) and the cooling face (40) of the cooling device (4); and o a locking device (6) assembled to the printed circuit (2) and to the cooling device (4), the locking device (6) being configured to immobilize the cooling device (4) on the printed circuit (2). Figure for abstract: Fig. 4

Description

Title of the invention: Electronic device enabling optimized cooling of electronic components

[0001] The invention relates to the field of on-board electronics. It relates more specifically to that of on-board electronic devices comprising an electronic card.

[0002] On-board electronic devices are used in various fields and for various applications (aeronautics, automotive, medical equipment, etc.). These electronic devices must meet certain constraints, in particular reduced size and increasingly high power. The increase in power at constant volume makes it difficult to cool the electronic components of on-board electronic devices.

[0003] In addition, embedded electronic devices must be able to withstand the constraints of their operating environment. These environmental constraints are related to temperature, random and sinusoidal vibrations, and shocks, and vary in particular depending on the area of use. Environmental constraints can be classified into three types: very mild, intermediate, and severe or even very severe. The standards VITA 20, VITA 48.x, VITA48.8, VITA 46, IEEE 1101.x, IEEE1386.X, VITA47 define these environmental constraints.

[0004] In very mild environments, the cooling devices for the electronic components of the electronic device may be mounted on a printed circuit of the electronic device by means of flexible mountings (spring mounting type).

[0005] This type of flexible mounting is not suitable for harsh or even very harsh environments in which temperatures can vary between -40°C and +85°C, random vibrations can reach 2000Hz, sinusoidal vibrations can reach 5g, and shocks can reach 40g. It is necessary for the cooling devices to be mounted on the electronic components that are to be cooled by means of rigid mountings capable of withstanding these environmental constraints.

[0006] [Fig.l] shows an example of a rigid mounting of the prior art. This figure shows in a sectional view an electronic device comprising a printed circuit board (or PCB), an electronic component mounted on the printed circuit board, and a cooling device configured to cool the electronic component. The electronic device further comprises screws allowing rigid mounting of the cooling device on the component. electronics. The screws pass through the printed circuit board and are inserted into recesses formed in the cooling device. An internal face of the cooling device, called the cooling face, is located opposite the electronic component to be cooled. Due to this assembly, a large space is present between the cooling face and the electronic component. This space is generally filled with a thermal blanket.

[0007] This prior art solution is not satisfactory from a thermal point of view. Indeed, a temperature loss of a few degrees Celsius is observed at the level of the thermal mattress. The cooling of the electronic component is therefore not effective.

[0008] The invention aims to provide an electronic device whose assembly makes it possible to withstand any type of environment and in particular severe or even very severe environments, and in which the cooling of the electronic components is effective.

[0009] The invention proposes for this purpose an electronic device comprising: - a printed circuit; - an electronic component assembled on the printed circuit; - a cooling device assembled to the printed circuit, the cooling device comprising a cooling face facing the electronic component; - a mounting system comprising: • a positioning device assembled to the cooling device, the positioning device being configured to adjust the distance between an upper face of the electronic component and the cooling face of the cooling device; and • a locking device assembled to the printed circuit and the cooling device, the locking device being configured to immobilize the cooling device on the printed circuit.

[0010] Thanks to the mounting system, and in particular to the positioning device, the invention makes it possible to improve the thermal contact between the cooling device and the electronic component to be cooled. This makes it possible to efficiently cool electronic components with a high power density.

[0011] The mounting system is advantageously rigid. The invention is thus of particular interest for use under severe or even very severe environmental constraints, but can be used in all types of environments.

[0012] Particularly convenient preferred features of the electronic device according to the invention are presented below.

[0013] The cooling device comprises at least one housing configured to receive the positioning device.

[0014] The housing is a through hole.

[0015] The positioning device comprises at least one adjustable column configured to be inserted into said at least one housing.

[0016] The adjustable column has a thread on an external surface.

[0017] The adjustable column includes a cavity configured to receive at least part the locking device.

[0018] The locking device comprises a screw having a threaded shank, the threaded shank passing through the printed circuit. The cavity of the adjustable column comprises a female thread complementary to the threaded shank of the screw.

[0019] The cooling device comprises several housings. Each housing extends near a periphery of the electronic component. The positioning device comprises as many adjustable columns as there are housings.

[0020] The locking device is assembled to the printed circuit and the remote cooling device of the positioning device.

[0021] The cooling device comprises at least one cavity configured to at least partially receive the locking device.

[0022] The electronic device further comprises a thermal connection between the upper face of the electronic component and the cooling face of the cooling device.

[0023] Other features and advantages of the invention will become apparent in the description below with reference to the appended drawings, given as non-limiting examples: - [Fig.l] is a sectional view of an electronic device of the prior art; - [Fig.2] is a perspective view of an electronic device according to a embodiment of the invention; - [Fig.3] is an exploded view of [Fig.2]; - [Fig.4] is a sectional view of a part of the electronic device of the [Fig.2] ; - Figures 5 to 8 show steps in assembling the electronic device of [Fig.2]; and - [Fig.9] is a sectional view of the electronic device according to another embodiment of the invention.

[0024] Figures 2 to 4 represent an electronic device 1 according to one embodiment of the invention.

[0025] The electronic device 1 comprises a printed circuit 2 (or PCB from the English printed circuit board).

[0026] The printed circuit 2 comprises at least one fixing hole 20. The circuit printed circuit 2 here comprises several fixing holes 20, in particular four fixing holes 20. The fixing holes 20 are for example through holes. In the example shown, the fixing holes 20 extend in a rectangular arrangement. Of course, the number, shape and / or arrangement (or positioning) of the fixing holes may vary. For example, the printed circuit 2 may comprise three fixing holes 20. The fixing holes 20 may then extend in a triangular arrangement.

[0027] The electronic device 1 also comprises at least one electronic component 3. The electronic component 3 is assembled on the printed circuit 2, for example by soldering.

[0028] The electronic device 1 here comprises several electronic components. The electronic components are assembled on the printed circuit 2. The printed circuit 2 serves as a mechanical support for the electronic components 3 and allows them to be electrically connected.

[0029] The invention is particularly concerned with electronic components generating a lot of heat. The electronic component 3 which heats up, here called hot electronic component 3, is for example a processor (or CPU from the English central Processing unit).

[0030] The electronic component 3 is assembled on a surface of the printed circuit 2 extending between the fixing holes 20. The fixing holes 20 thus extend around the electronic component 3. More precisely, each fixing hole 20 extends close to a corner of the electronic component 3.

[0031] The electronic device 1 also comprises a cooling device 4 or heat sink. The cooling device 4 is configured to cool the hot electronic component 3. The cooling device 4 is configured to absorb the heat from the electronic component 3 and dissipate it into the ambient air, thereby maintaining an optimal operating temperature.

[0032] The cooling device 4 comprises a cooling face 40 (visible in [Fig.4]) facing the electronic component 3. The cooling face 40 is facing an upper face 30 of the electronic component 3.

[0033] The cooling device 4 here comprises cooling fins 4L. The cooling fins 41 extend vertically. The cooling fins 41 facilitate convection cooling. Of course, the cooling device 4 may have a different structure. In an exemplary embodiment not shown, the cooling device 4 may be a conduction cooling device.

[0034] The cooling device 4 comprises at least one housing 42. The cooling device 4 here comprises the same number of housings 42 as the number of fixing holes 20 of the printed circuit 2. The cooling device 4 here comprises several housings 42, in particular four housings 42. The housings 42 extend in a rectangular arrangement. The housings 42 thus extend around the electronic component 3. More precisely, each housing 42 extends near a corner of the electronic component 3.

[0035] In the embodiment of Figures 2 to 8, the housings 42 are located opposite the fixing holes 20 once the cooling device 4 is assembled to the printed circuit 2. Of course, the number, shape and / or arrangement (or positioning) of the housings may vary. For example, the cooling device 4 may comprise three housings 42. The housings 42 may then extend in a triangular arrangement.

[0036] The housings 42 may be holes, typically through or blind holes. The housings 42 have a cylindrical shape.

[0037] The electronic device 1 further comprises a mounting system. The mounting system comprises a positioning device 5 and a locking device 6. The mounting system is rigid. In particular, the positioning device 5 and the locking device 6 are rigid.

[0038] The positioning device 5 is assembled to the cooling device 4.

[0039] The positioning device 5 is configured to position the re cooling 4 relative to the electronic component 3. The positioning device 5 is configured to adjust the distance between the upper face 30 of the electronic component 3 and the cooling face 40 of the cooling device 4. The positioning device 5 makes it possible to reduce as much as possible the space between the upper face 30 of the electronic component 3 and the cooling face 40 of the cooling device 4. The positioning device 5 makes it possible to bring the cooling device 4 into contact with the electronic component 3 to be cooled.

[0040] The positioning device 5 comprises adjustable columns 51. The positioning device 5 comprises the same number of adjustable columns 51 as the number of housings 42 of the cooling device 4. The positioning device 5 here comprises four adjustable columns 51. Each adjustable column 51 has a shape complementary or similar to the shape of the housings 42. Each adjustable column 51 has a cylindrical shape. Each adjustable column 51 extends at least partly into one of the housings 42. The adjustable column 51 extending into the housing 42 may protrude partly from the housing 42 as visible in [Fig.4].

[0041] Each adjustable column 51 has a thread 510 on an external surface. Thanks to the thread system, it is possible to adjust the height position of the device. cooling 4 relative to the electronic component 3. In other words, the thread system makes it possible to adjust the distance between the upper face 30 of the electronic component 3 and the cooling face 40 of the cooling device 4.

[0042] The adjustable columns 51 make it possible to conform to the deformation of the printed circuit 2. Indeed, since the printed circuit 2 is not always perfectly flat, the height adjustment using the adjustable columns 51 makes it possible to compensate for these flatness defects of the printed circuit 2. This also avoids stressing the printed circuit since the positioning device 5 of the invention allows an adjustment in accordance with the geometry of the printed circuit 2. For example, the adjustable columns 51 can be inserted at different heights in the housings 42 in order to adapt to the geometry of the printed circuit 2.

[0043] A fastening means is used to immobilize each adjustable column 51 in the associated housing 42. The fastening means prevents the threads from loosening under the effect of vibrations or shocks.

[0044] The fixing means is for example an adhesive applied to the thread 510 of the adjustable column 51 prior to its insertion into the housing 42. The fixing means may be thread lock, preferably strong thread lock so that the assembly of the adjustable columns 51 in the housings 42 can withstand severe or even very severe environmental constraints.

[0045] The fixing means may alternatively be solder or an adhesive substance poured into the housings 42 after insertion of the adjustable columns 51 into the housings 42.

[0046] In the example shown, each adjustable column 51 comprises a cavity 511. The cavity 511 is configured to receive at least a portion of the locking device 6. The cavity 511 opens onto one end 512 of the adjustable column 51. The cavity 511 has a substantially cylindrical shape. The cavity 511 comprises a female thread or tapping (not shown in the figures).

[0047] The locking device 6 is assembled to the printed circuit 2 and to the cooling device 4.

[0048] The locking device 6 is configured to immobilize the cooling device 4 on the printed circuit 2. In other words, the locking device 6 locks the cooling device 4 in its position on the printed circuit 2.

[0049] The locking device 6 comprises at least one screw 60. The locking device 60 here comprises several screws 60, in particular four screws 60. The locking device 6 comprises the same number of screws 60 as the number of fixing holes 20 of the printed circuit 2.

[0050] Each screw 60 comprises a rod 600 and a head 601. The rod 600 of each screw 60 passes through one of the fixing holes 20 of the printed circuit 2. In the example of rea 2 to 8, the rod 600 of each screw 60 opens into one of the cavities 511 of the corresponding adjustable column 51. Once the head 60 is assembled to the printed circuit 2 and to the cooling device 4, the head 601 is located against a lower face of the printed circuit 2.

[0051] The rod 600 of each screw 60 is for example threaded. The thread of the threaded rod 600 is complementary to the female thread of the cavity 511 of each adjustable column 51.

[0052] A fastening means is used to immobilize each screw 60 in the corresponding cavity 511. The fastening means prevents the threads from loosening due to vibrations or shocks. The fastening means is for example an adhesive applied to the shank 600 of the screw 60 prior to its insertion into the cavity 511. The fastening means may be thread lock, preferably weak thread lock so as to allow easy disassembly of the screw 60 in the event of the need to intervene on the electronic device 1.

[0053] The electronic device 1 further comprises a thermal connection 7. The thermal connection 7 extends between the upper face 30 of the electronic component 3 and the cooling face 40 of the cooling device 4. The thermal connection 7 is made of a material making it possible to fill gaps or holes present on the surface of the electronic components. The thermal connection ensures good heat conduction. The thermal connection 7 is for example a layer of thermal grease, a thermal blanket, etc. The thermal connection 7 is for example applied to the upper surface 30 of the electronic component 3 prior to mounting the cooling device 4 on the electronic component 3 and the printed circuit 2.

[0054] The thermal grease offers high thermal performance, thus enabling efficient cooling of the electronic component 3. The thermal grease has the particular advantage of having an extremely low thickness (of the order of a few microns), thus reducing the thermal resistance.

[0055] In another exemplary embodiment, the electronic device 1 may not include a thermal connection 7. The cooling face 40 of the cooling device is in direct contact with the upper surface 30 of the electronic component 3.

[0056] Figures 5 to 8 show the assembly steps of the electronic device 1 according to the previously described embodiment.

[0057] As seen in [Fig.5], the adjustable columns 51 are first inserted into the housings 42 of the cooling device 4.

[0058] The printed circuit 2 and the cooling device 4 are then brought opposite each other ([Fig.6]). The cooling device 4 is positioned above the electronic component 3. In particular, in the example shown, the housings 42 are brought opposite the fixing holes 20 of the printed circuit 2.

[0059] The adjustable columns 51 are arranged at the desired height inside the housings 42 ([Fig.7]). This makes it possible to adjust the position of the cooling device 4 relative to the electronic component 3. In fact, the distance between the cooling face 40 of the cooling device 4 and the upper face 30 of the electronic component 3 is adjusted by means of the adjustable columns 51. This distance is minimized as much as possible so as to bring the cooling face 40 into contact with the upper face 30 of the electronic component or with the thermal connection 7 extending over the upper face 30 of the electronic component 3.

[0060] Thanks to the positioning device 5, the reference surface for mounting the electronic device 1 is the electronic component 3. This makes it possible to bring the cooling device 4 into contact with the electronic component 3, thus improving the cooling efficiency of the electronic component 3.

[0061] The positioning device 5 is kept stationary by the fixing means, as explained above. For example, thread lock is applied to the thread 510 of each adjustable column 51 prior to the insertion of each adjustable column 51 into the housings 42 of the cooling device 4.

[0062] The screws 60 are finally inserted into the fixing holes 20 of the printed circuit 2 ( [Fig.8]). The screws 60 are screwed into the cavities 511 of the adjustable columns 51. The cooling device 4 is thus locked and made integral with the printed circuit 2.

[0063] The mounting system of the previously described embodiment has the advantage of being compact. Indeed, the mounting system has a structure such that the positioning device 5 and the locking device 6 are assembled to each other.

[0064] In another exemplary embodiment shown in [Fig.9], the positioning device 5 and the locking device 6 are not assembled to each other. The positioning device 5 and the locking device 6 are at a distance from each other. This exemplary embodiment differs from the previous one in that the adjustable columns 51 do not include a cavity. The adjustable columns 51 are thus solid cylinders. The cooling device 4 itself includes cavities 43. The cavities 43 of the cooling device 4 allow the locking device 6 to be received. The fixing holes 20 of the printed circuit 2 are formed to be offset horizontally relative to the housings 42 when the cooling device 4 is assembled to the electronic component 3.In other words, the fixing holes 20 are not opposite the housings 42 when the cooling device 4 is assembled to the electronic component 3. The fixing holes 20 are configured to be opposite the cavities 43 of the device. cooling 4 when the cooling device 4 is assembled to the electronic component 3.

[0065] In the embodiment of [Fig.9], the locking device 6 also comprises screws 60, in particular screws 60 each comprising a head 600 and a rod 601. The rod 601 of each of the screws 60 is here not threaded. The cavities 43 of the cooling device 4 each comprise a female thread complementary to the threaded rods 501 of the screws 60.

[0066] Alternatively to the unthreaded screws of [Fig.9], the locking device 6 may comprise screws having threaded shanks. In this case, the cavities of the cooling device may comprise a female thread complementary to the threaded shanks of the screws.

[0067] Alternatively, the locking device 6 may comprise headless screws, or be formed by stops assembled to the printed circuit 2 and allowing the cooling device 4 to be locked onto the printed circuit 2.

[0068] The electronic device according to the invention allows rigid mounting of the cooling device on the hot electronic component, coming into contact with the hot electronic component so as to create a high-performance thermal interface.

[0069] The description of the present invention is made for an electronic device comprising an electronic component (in particular a hot electronic component), a cooling device configured to cool said electronic component, and a mounting system configured to allow the positioning and locking of the cooling device on the electronic component. Of course, the electronic device may comprise several electronic components to be cooled (i.e. several hot electronic components). In this case, the electronic device may comprise a cooling device associated with each electronic component to be cooled, and a mounting system associated with each pair formed by the cooling device and the associated electronic component.

Claims

Claims

1. Electronic device comprising: - a printed circuit (2); - an electronic component (3) assembled on the printed circuit (2); - a cooling device (4) assembled to the printed circuit (2), the cooling device (4) comprising a cooling face (40) facing the electronic component (3); - a mounting system comprising: • a positioning device (5) assembled to the cooling device (4), the positioning device being configured to adjust the distance between an upper face (30) of the electronic component (3) and the cooling face (40) of the cooling device (4); and • a locking device (6) assembled to the printed circuit (2) and to the cooling device (4), the locking device (6) being configured to immobilize the cooling device (4) on the printed circuit (2).

2. Electronic device according to claim 1, wherein the cooling device (4) comprises at least one housing (42) configured to receive the positioning device (5).

3. An electronic device according to claim 2, wherein the housing (42) is a through hole.

4. An electronic device according to claim 2 or claim 3, wherein the positioning device (5) comprises at least one adjustable column (51) configured to be inserted into said at least one housing (42).

5. An electronic device according to claim 4, wherein the adjustable column (51) has a thread (510) on an external surface.

6. An electronic device according to claim 4 or claim 5, wherein the adjustable column (51) comprises a cavity (511) configured to at least partially receive the locking device. (6).

7. Electronic device according to claim 6, wherein the locking device (6) comprises a screw (60) having a threaded rod (600), the threaded rod (600) passing through the printed circuit (2), the cavity (511) of the adjustable column (51) comprising a female thread complementary to the threaded rod (600) of the screw (60).

8. Electronic device according to one of claims 4 to 7, in which the cooling device (4) comprises several housings (42), each housing (42) extending close to a periphery of the electronic component (3), the positioning device (5) comprising as many adjustable columns (51) as housings (42).

9. Electronic device according to one of claims 1 to 5, wherein the locking device (6) is assembled to the printed circuit (2) and to the cooling device (4) at a distance from the positioning device (5).

10. Electronic device according to claim 9, wherein the cooling device (4) comprises at least one cavity (43) configured to receive at least in part the locking device (6).

11. Electronic device according to one of claims 1 to 10, further comprising a thermal connection (7) between the upper face (30) of the electronic component (3) and the cooling face (40) of the cooling device (4).

Images