Cover for pressing a printed circuit board against a heat sink

Abstract

A lid for pressing a printed circuit board against a heat sink is provided, the lid comprising a metal sheet and one or more domes arranged in the metal sheet, wherein each dome is associated with one or more slits of an annular segment shape in the metal sheet, the annular segment-shaped slits being arranged side by side in the metal sheet and spaced apart from each other, the annular segment-shaped slits surrounding the dome associated therewith. At least at one end of each annular segment-shaped slit, a slit extension can be provided in the metal sheet, the slit extension pointing at least partially away from the dome associated with the annular segment-shaped slit. An electronic appliance is also provided, the electronic appliance comprising such a lid, a heat sink and an electronic circuit board sandwiched therebetween.

Description

[0001] This disclosure relates to a cover for pressing a printed circuit board onto a heat sink, and to an electronic device having such a cover. The electronic device may be, for example, an amplifier that can be used in a vehicle, but is not limited thereto. Background Technology

[0002] Printed circuit boards (PCBs) used in amplifiers or other electronic devices are typically arranged between a heat sink and a cover that presses the PCB against the heat sink. The heat sink typically includes several fins to dissipate heat generated by integrated circuits (ICs), particularly power ICs, and other electronic components on the PCB. The cover typically comprises a thin metal sheet with multiple domes embossed on it. These domes point towards the PCB and are pressed / pushed onto specific points on the PCB corresponding to the locations of ICs or other heat-generating electronic components. With the domes pressed against these points, and thus against the heat-generating components on the PCB, the heat-generating components are pressed against the heat sink.

[0003] However, dimensional differences in the height of ICs and other heat-generating components, as well as variations in the size of the heatsink and the shape of the cover's metal sheet after installation, often lead to deviations in the pressure applied by the dome, and may even result in the dome not making contact with the IC and other heat-generating components. The cover and heatsink are typically mounted with screws, which can cause warping or denting of the metal sheet cover. To avoid such deformation of the cover, reinforcing ribs are usually integrated into the cover for reinforcement, thereby minimizing warping of the metal sheet. Furthermore, the height of the dome can be chosen to be greater than the height it appears to require in the unmounted state to address twisting / warping during installation. However, the achieved contact pressure is often uneven. Summary of the Invention

[0004] This disclosure relates to a cover for pressing a printed circuit board onto a heat sink. The cover includes a metal sheet and one or more domes disposed within the metal sheet. The metal sheet includes one or more domes. Each dome points in the same direction. The metal sheet and the one or more domes may be integrally formed. Each dome is associated with one or more annular slits disposed within the metal sheet. These annular slits are arranged side-by-side in the metal sheet and spaced apart from each other. The annular slits surround the dome associated with / assigned to them. That is, the annular slits are arranged on a circular object surrounding the corresponding dome. On the circular object, the annular slits are arranged at a distance from each other and may be evenly distributed on the circular object. When the annular slits are arranged at a distance from each other, spokes are disposed in the metal sheet, and the spokes connect the corresponding dome to the metal sheet (the remainder). The spokes may extend in a radial direction, may be inclined at a predefined angle, or may be bent or flexed by a corresponding design at the ends of the annular slits.

[0005] At least at one end of each annular slit, a slit extension may be disposed in a metal sheet, the slit extension being at least partially away from the corresponding dome. At each annular slit, the slit extension may be disposed at the same end.

[0006] Each annular slit extension may be formed such that it at least partially surrounds an adjacent annular slit, wherein the slit extension is spaced apart from the adjacent annular slit. The slit extension may surround less than half the length of the adjacent annular slit. Each annular slit extension may include a first slit extension and a second slit extension. The first slit extension may extend away from the corresponding dome. The first slit extension may extend radially, may be inclined at a predefined angle, or may be bent or flexed. The second slit extension may extend from the end of the first slit extension opposite the end connected to the annular slit. The second slit extension may have an annular shape and may extend parallel or spirally to the adjacent annular slit, spaced apart from it.

[0007] Alternatively, slit extensions may be provided at both ends of each annular slit. The slit extensions may extend radially away from the corresponding dome. The slit extensions may also be inclined at a predefined angle, or may be bent or flexed. Slit extensions provided at different ends of the annular slits may be mirror images of each other, i.e., they may be axially symmetrical with respect to the radial direction / axis. For example, grooves in the form of notches or channels may be provided in the sheet between two adjacent slit extensions of adjacent annular slits. The longitudinal direction of the groove may be perpendicular to the longitudinal direction of the slit extension. The groove may connect adjacent slit extensions. The groove is recessed in the same direction as the dome.

[0008] This disclosure further relates to an electronic device comprising a cover, a heat sink, and an electronic circuit board as described herein. The electronic circuit board is sandwiched between the cover and the heat sink, such that the dome of the cover presses the electronic circuit board, i.e., its integrated circuits and other heat-generating electronic components, against the heat sink for heat transfer and dissipation. Amplifiers, such as those used in vehicles, may constitute, for example, an electronic device in the sense of this disclosure. Other electronic devices are also possible.

[0009] The dome is separated from the metal sheet of the cover by an annular slit, particularly the slit extension. That is, these areas are separated from the metal sheet of the cover, which may flex when the printed circuit board of an electronic device is pushed against a heat sink. When the dome is pressed against a specific location on the printed circuit board where integrated circuits and other heat-generating electronic components reside, proper thermal contact between the integrated circuits and other heat-generating electronic components and the heat sink can be achieved, thereby supporting heat transfer and dissipation. By separating the dome from the metal sheet, warping of the metal sheet can be avoided or at least reduced.

[0010] If the integrated circuits and other heat-generating electronic components on the printed circuit board have different heights, such height differences can be compensated by appropriate spring suspension of the dome within the metal sheet of the cover. This spring suspension is achieved by providing annular slits, particularly slit extensions, within the metal sheet of the cover. Specifically, by providing slit extensions of different shapes and sizes, the spring behavior of the dome can be individually adjusted to provide individually adapted pressure / compression / spring force, thus addressing such height differences without compromising heat transfer to the heat sink. In other words, the cover of this disclosure ensures proper thermal contact between integrated circuits and other heat-generating electronic components of different heights and the heat sink.

[0011] The annular slits and slit extensions can be fully integrated into existing metal sheets with integrated domes without significantly increasing cost or workload. By separating the dome from the metal sheet, the requirements for the manufacturing and installation precision of the additional mechanical components of the cover can be relaxed; tolerances can be greater. Attached Figure Description

[0012] The embodiments are described by way of example with reference to the accompanying drawings which are not drawn to scale, wherein the same reference numerals refer to similar elements.

[0013] Figure 1 An exploded view of the electronic device is shown;

[0014] Figure 2 One embodiment of the cover is shown;

[0015] Figure 3 Another embodiment of the cover is shown;

[0016] Figure 4 Another embodiment of the cover is shown;

[0017] Figure 5 Another embodiment of the cover is shown;

[0018] Figure 6 Another embodiment of the cover is shown;

[0019] Figure 7 Another embodiment of the cover is shown;

[0020] Figure 8 Show Figure 5 A cover with a displaced dome; and

[0021] Figure 9 Showing when the dome is like Figure 8 During the shift shown, by Figures 1 to 6 A comparison of the combined pressures applied to the corresponding domes of the shown caps. Detailed Implementation

[0022] Figure 1 An embodiment of an electronic device 100 in the form of an amplifier, such as used in a vehicle lifestyle audio system, is shown. The electronic device 100 includes a printed circuit board 102 having various electronic components such as integrated circuits, a heat sink 104 having heat sinks 106 arranged on a side opposite to the printed circuit board 102, and a cover 108. The electronic components are arranged on the printed circuit board 102, opposite the cover, facing the heat sink 104. The cover 108 and the heat sink 104 are attached to the printed circuit board 102 by screws or the like. For illustrative purposes, Figure 1 Only the screws 110 used to attach the cover 108 to the printed circuit board 102 are shown. The heat sink 104 may be made of aluminum. The cover 108 may be made of stainless steel.

[0023] Cover 108 includes a metal sheet 112 and a plurality of domes 114 pointing toward a printed circuit board 102. The domes 114 are embossed into the metal sheet 112. The domes 114 are arranged in the metal sheet 112 in a manner described in more detail below. During assembly, the printed circuit board 102 is sandwiched between the heat sink 104 and cover 108 such that the domes 114 of cover 108 apply pressure to specific locations on the lower side of the printed circuit board 102, where integrated circuits and other electronic components are arranged on the upper side of the printed circuit board 102. In this document, the terms “upper,” “lower,” “topmost,” “lowest,” and similar terms relate to the presentation in the various figures. With pressure applied at these specific locations by the domes 114, the corresponding electronic components are pushed against the heat sink 104 and support heat transfer and heat dissipation to the heat sink.

[0024] Figure 2 An embodiment of the cover 200 is shown. The cover 200 includes a metal sheet 202 and a dome 204. A plurality of domes 204 may be disposed in the metal sheet 202. A plurality of annular slits 206 are disposed in the metal sheet 202. The annular slits 206 are arranged side by side (i.e., adjacent) to each other on a circular body surrounding the domes 204, while being spaced apart, particularly spaced apart by equal distances, such that spokes 208 are retained. The spokes 208 connect the domes 204 to the metal sheet 202 (the remainder). Depending on the shape of the ends of the annular slits 206, the spokes 208 may extend in the radial direction, or they may be inclined / angled, bent, or curved. Three annular slits 206 in Figure 3 As shown in the diagram. However, more or fewer than three annular slits can be provided, their lengths being individually adjustable. It is even conceivable to provide an annular slit 206 whose ends are not connected, i.e., its ends are spaced apart and form a spoke 208 through which the dome 204 is connected to the metal sheet 202. By providing the annular slit 206, the dome 204 is flexibly suspended from the metal sheet 202 via the spoke 208. The cover 200 can be made of stainless steel.

[0025] Figure 3 An embodiment of the cover 300 corresponding to the cover 200 is shown, but in which, in addition to the annular slits 306, slit extensions 310 are provided in the metal sheet 302. Slit extensions 310 are provided at both ends of each annular slit 306, specifically pointing radially away from the dome 304. The slit extensions 310 can also extend at an angle. They can also be bent or folded. The slit extensions 310 provided at different ends of the annular slits 306 can have a mirror-reversed shape, i.e., they can be axially symmetrical relative to the radial direction / axis. By providing slit extensions 310, the spokes 308 become longer (longer than...). Figure 2 The spokes 208), thus causing the spokes to be in contact with the spokes. Figure 2 Compared to the dome 204 of the cover 200 shown (see also...) Figure 9 (Comparison in the text) The dome 304 has lower suspension stiffness in the metal sheet 302.

[0026] Figure 4 It shows the relationship with Figure 3 The illustrated cover 300 corresponds to one embodiment of the cover 400, but in which a groove 412 is additionally provided between the adjacent slit extensions 410 of two adjacent annular slits 406. The groove 412 connects the adjacent slit extensions 410 of the adjacent annular slits 406. The groove 412 is provided in the metal sheet 402 in the spokes 408 between the adjacent slit extensions 410. The longitudinal direction of the groove 412 may be perpendicular to the longitudinal direction of the slit extensions 410. The groove 412 is recessed in the same direction as each dome 404 provided in the metal sheet 402. The groove 412 can be provided in the metal sheet 402 by embossing. Figure 3 Compared to the dome 304 of the cover 300 shown (see also...) Figure 9 (Comparison in the text) The groove 412 in the spoke 408 results in an even lower suspension stiffness of the dome 404 in the sheet 402.

[0027] Figure 5 It shows the relationship with Figure 2The illustrated cover 200 corresponds to one embodiment of the cover 500, but in which a slit extension 510 is provided only at one end of each annular slit 506. The end of each annular slit 506 where the slit extension 510 is provided may be the same end of each annular slit 506. The slit extension 510 points at least partially away from the dome 504. Relative to the dome 504, the slit extension 510 extends on the opposite side of the annular slit 506. Each slit extension 510 is formed such that at least a portion of it at least partially surrounds the adjacent annular slit 506 while being spaced apart from the adjacent annular slit 506. For this purpose, the slit extension 510 of each annular slit 506 may include a first slit extension portion 510a and a second slit extension portion 510b.

[0028] The first slit extension 510a may extend radially away from the dome 504. The first slit extension 510a may also extend at an angle. It may also bend or curve. The second slit extension 510b may extend from the end of the first slit extension 510a opposite to the end of the first slit extension 510a that is connected to the corresponding annular slit 506. That is, the second slit extension 510b is connected to the end of the first slit extension 510a that is not directly connected to the annular slit 506. The second slit extension 510b may have an annular shape similar to but shorter than the annular slit 506, and may extend parallel or spirally to the adjacent annular slit 506 but spaced apart from it. Figure 4 Compared to the dome 404 of the cover 400 shown (see also...) Figure 9 (Comparison in the middle) Figure 5 The cover 500 shown exhibits even lower suspension stiffness of the dome 504 within the sheet 502.

[0029] Figure 6 The cover 600 shown is Figure 5 Corresponding to the cover 500 shown, the difference is that the second slit extension 610b of the cover 600 is longer than the second slit extension 510b of the cover 500. That is, the second slit extension 610b of the cover 600 is longer than... Figure 5 The second slit extension 510b of the illustrated embodiment surrounds more adjacent annular slits 606. This results in... Figure 5 Compared to the dome 504 of the cover 500 shown (see also...) Figure 9 (Comparison in the middle) Figure 6 The cover 600 shown exhibits even lower suspension stiffness of the dome 605 within the sheet 602. Figure 6 The first slit extension 610a may correspond to Figure 5The first slit extension 510a. The slit extensions 510, 610, and especially their second slit extensions 510b, 610b, may surround a length less than half that of the adjacent annular slits 506, 606.

[0030] Figure 7 A cover 700 is shown having a plurality of domes 704 disposed in a metal sheet 702. Each dome 704 is surrounded by an annular slit 706, which may correspond to... Figure 6 The cover 600 shown has an annular slit 606. The annular slit 606 is provided with a slit extension 710, which includes a first slit extension portion 710a and a second slit extension portion 710b. The slit extension portion 710, the first slit extension portion 710a, and the second slit extension portion 710b of the cover 700 can be correspondingly combined. Figure 6 The cover 600 shown and described includes a slit extension 610, a first slit extension 610a, and a second slit extension 610b. Some domes of the cover 700 may also be provided with... Figures 3 to 5 As shown and combined Figures 3 to 5 Other combinations of the annular slit and slit extension. Furthermore, a dome 704a may be provided in the metal sheet 702, which may have an annular slit 706 without the slit extension. Additionally, a rib 712 may be provided in the metal sheet 702 to increase the rigidity of the metal sheet 702 of the cover 700.

[0031] Figure 9 The diagram illustrates the combined pressure / compression / spring force when the domes 204, 304, 404, 504, and 604 of the covers 200, 300, 400, 500, and 600 are displaced (pushed downward) by a certain amount in the z-direction, which is perpendicular to the plane of the metal sheets 202, 302, 402, 502, and 602 (assuming no warping / twisting or other displacement of the metal sheets). Figure 8 The diagram shows a cover 800 with x, y, and z axes added to a Cartesian coordinate system. Cover 800 exemplarily corresponds to... Figure 5 The cover shown from top to bottom is 500, but it can be any of the covers 200, 300, 400, 500, and 600.

[0032] exist Figure 9 In the middle, the cover 900 shown on the left corresponds to Figure 2 The depicted cover 200, while the cover 920 shown on the right corresponds to... Figure 6 The depicted cover 600. In the figure, the horizontal axis represents the degree of dome displacement in mm, and the vertical axis represents the combined pressure / compression force / spring force in N. The uppermost curve shows the dome of cover 900 (i.e., Figure 2 The dome 204 of the cover 200 shown is in Figure 9 The combined spring force (also known as "Cover 050"). The second uppermost curve shows... Figure 3 The dome 304 of the cover 300 shown (in) Figure 9 The combined spring force (also known as "Cover 030") is shown in the middle curve. Figure 4 The dome 404 of the cover 400 shown (in) Figure 9 The combined spring force (also known as "Cover 040"). The second lowest curve shows... Figure 5 The dome 504 of the cover 500 shown (in) Figure 9 The combined spring force (also referred to as "cover 010" in the text). The lowest curve shows the dome of cover 920 (i.e., Figure 6 The dome 604 of the cover 600 shown is in Figure 9 The combined spring force (also known as "Gai 020" in Chinese).

[0033] and Figures 2 to 6 Consistent with the above description, the dome of cover 900 exhibits the highest spring force, i.e., the highest stiffness, and therefore the lowest flexibility during displacement, while the dome of cover 920 exhibits the lowest spring force, i.e., the lowest stiffness, and therefore the highest flexibility during displacement. This makes cover 920 particularly suitable for pressing printed circuit boards with electronic components of varying heights against heat sinks for safe heat transfer and dissipation, while ensuring minimal or no warping of the cover's metal plates.

Claims

1. A cover for pressing a printed circuit board onto a heat sink, the cover comprising: Metal sheet; as well as One or more domes arranged in the metal sheet, Each dome is associated with one or more annular slits in the metal sheet, the annular slits being arranged side-by-side and spaced apart from each other, the annular slits surrounding the dome with which they are associated. At least at one end of each annular slit, a slit extension is disposed in the metal sheet, the slit extension being at least partially away from the annular slit and its associated dome orientation. The slit extensions are located at both ends of each annular slit. The groove is disposed in the metal sheet between two adjacent slit extensions of adjacent annular slits, the longitudinal direction of the groove being perpendicular to the longitudinal direction of the slit extension, wherein the groove connects the adjacent slit extensions and is recessed in the same direction as each dome.

2. The cover as claimed in claim 1, wherein the slit extension is disposed at the same end of the annular slit.

3. The cover of claim 2, wherein the slit extension of each annular slit is formed such that it at least partially surrounds the adjacent annular slit, the slit extension being spaced apart from the adjacent annular slit.

4. The cover of claim 3, wherein the slit extension of each annular slit surrounds less than half the length of the adjacent annular slit.

5. The cover as claimed in claim 3 or 4, wherein the slit extension of each annular slit includes a first slit extension portion and a second slit extension portion, the first slit extension portion extending away from the annular slit and its associated dome, and the second slit extension portion extending from an end of the first slit extension portion opposite to the end connected to the annular slit, the second slit extension portion having an annular shape and extending parallel or spirally to the adjacent annular slit spaced apart from it.

6. The cover of claim 1, wherein the slit extension extends radially away from the annular slit and the dome associated therewith.

7. The cover as claimed in any one of claims 1-4, wherein the metal sheet and the one or more domes are integrally formed.

8. An electronic appliance comprising a cover, a heat sink, and an electronic circuit board according to any one of the preceding claims, wherein the electronic circuit board is sandwiched between the cover and the heat sink such that the dome of the cover presses the electronic circuit board onto the heat sink.

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