Heat sink fastening assembly for electronic components

Abstract

Heatsink mounting assembly for electronic components, which has elements for positioning the heatsink (16) in the heat generating part (15) of the electronic component (14) in such a way as to ensure heat dissipation by heat transfer, as flexible support pins extending at a predetermined angle relative to the plane of the carrier (13) holding the electronic component (14) (11, 12) are formed, one end of which is mountable on the surface of the carrier (13), the other end is connected to the cooling fin (16) in a force-locking connection that secures the position ensuring heat transfer between the cooling fin (16) and the heat generating part (15) of the component (14). ŕ

Description

The invention generally relates to a heat sink mounting assembly for electronic components, which has elements for positioning the heat sink on the heat generating part of the electronic component in a manner that provides heat dissipation by heat transfer. The size of electronic components in microelectronic modules is decreasing, but at the same time the known difficulties associated with the heat dissipation of the components have not decreased. The size of the heat sinks required to cool the components used in modern electronic stages is increasing compared to the components, and both their attachment and removal are difficult for the people involved. In our description, a heat sink is any assembly, usually made of metal, that, in contact with an electronic component, absorbs heat from its heat-generating part, conducts it away, and dissipates it through its variously designed, relatively large heat transfer surfaces. In the field of microelectronics, the increase in circuit density and the decrease in the size of electronic components continuously increase the problems related to heat dissipation and heat removal. If cost is not a significant factor, these problems can be safely eliminated, but apart from this, the simplicity or complexity of assembly and its cost also appear as non-negligible factors. US Patent No. 5,384,940 describes a heat sink mounting assembly that clamps a heat sink to the surface of an electronic component that dissipates heat. The heat sink is connected to the component carrier by flexible, split retaining pins that are positioned at a defined angle, substantially perpendicular to the carrier. One end of the retaining pins is connected to the heat sink and the other end is connected to the carrier. Good thermal contact is ensured by the clamping force created by a coil spring. The retaining pins may be made of plastic and arranged symmetrically, and the heat sink contains openings for the retaining pins. The retaining pins may also be part of a single component formed as a common assembly, and the flexible element, i.e. the coil spring, providing the clamping force may be a component made of the same material as the retaining pin and manufactured in the same process as the retaining pin. However, the resulting relationship allows for only ad hoc, rough positioning that may change over time. Our goal with the invention is to be able to hold and fix a heat sink to an electronic component in a simple way, including the design of a heat sink fixing assembly that is simple, inexpensive to manufacture, and easy to install. In solving the problem, a heat sink mounting assembly for electronic components was used as a basis, which has elements for positioning the heat sink in the heat generating part of the electronic component in a manner that ensures heat dissipation by heat transfer. The elements are designed as flexible support pins extending at a predetermined angle relative to the plane of the carrier holding the electronic component, one end of which is in a force-locking connection with the heat sink, fixing the position between the heat sink and the heat generating part of the component, ensuring heat transfer. According to the invention, the other end of the support pins is mountably mounted on the surface of the carrier. According to a preferred embodiment of the heat sink mounting assembly according to the invention, the heat sink is connected to the mounting ribs in a non-positive manner. According to a further preferred embodiment of the heat sink mounting assembly according to the invention, the retaining pins are made of plastic. It is also advantageous according to the invention if the retaining pins are made of plastic containing metal parts necessary for soldering. It is also preferable if the support pins are made of metal. In addition to the above, it is advantageous if the carrier comprises four support pins arranged symmetrically in a quadrangle on its surface. It is also advantageous according to the invention if the support pins are connected to support elements extending in a rectangular shape fixed on the surface of the carrier. According to a further preferred embodiment of the heat sink mounting assembly according to the invention, a layer of heat-conducting material is arranged between the heat-generating part of the electronic component and the heat sink. In the latter case, it is advantageous if the thermally conductive material layer is a thermally conductive paste. In addition to the above, it is also advantageous if the heat sink comprises at least two openings mechanically connected to the flexible support pins. It is further preferred that the flexible support pins are made of plastic and include locking ribs at their ends mechanically connected to the heat sink. It is also advantageous according to the invention if the support pins are made of a metal allowing a soldered connection to the support elements attached to the surface of the carrier. The invention is described in more detail below with the aid of the attached drawing, which shows some exemplary embodiments of the proposed heat sink mounting assembly. In the drawing, Figure 1 is an exploded view of a possible embodiment of the proposed heat sink mounting assembly, Figures 2-4 show some embodiments of the retaining pin according to the invention, Two additional possible mounting assembly designs can be seen in Figures 5 and 6, and the Figures 7 and 8 each show a schematic side view of another possible heat sink mounting assembly design. The heat sink mounting assembly shown in Figure 1 shows two mounting elements 10, which also include retaining pins 11, 12. The number and location of the retaining pins 11, 12 depend on the size, weight, thermal conductivity, and possibly other safety factors of the heat sink 16. The design of the retaining pins 11, 12 will be described in more detail later, but it is only emphasized here that their placement does not necessarily require holes or other openings in the carrier 13 holding the retaining pins 11, 12. In our description, the carrier 13 is considered to be an element that is made of some known material. HU 221 213 Β1 carries one or more components 14, and this component has a heat generating part 15, the heat generated by which must be removed from the component 14 to the environment. The heat sink 16 contains openings 17, which are designed to fit the support pins 12 and serve to receive them. In the case of the arrangement shown in Figure 1, no holes, openings, or openings need to be made in the carrier 13, because the support pins 12 can be attached directly to the carrier 13 using a frame or support element, or they can be glued, soldered, or fixed in other known ways, for example with a self-tapping screw wound from above. When sizing and designing the support pins 12, we only need to take into account that they must be able to securely attach the heat sink 16 to the carrier 13 in the manner described in the description, and they must fit into the openings 17 of the heat sink 16. As an essential feature of our invention, the cooling fin 16 can be conveniently fixed to the component 14 and its heat-generating part 15 by means of the retaining pins 12. Figures 2, 3 and 4 show some of the preferred designs of the support pins. In Figure 2, a support pin 20 is attached to relatively shorter support legs 21, 22, which are mostly at right angles to each other. The length and thickness of the support legs 21, 22 depend on several factors, including the amount of force required for the support pins 20 to bend flexibly towards each other and hold the heat sink with sufficient force, and for the support pins 20 to be able to be bent to remove the heat sink 16. We will return to the flexibility of the support pins 20 later. The support pin 20 shown in Figure 2 has a pentagonal cross-section in order to have a fifth, substantially flat surface 25 towards the meeting edge 24 of the support legs 21,22. A certain number of fixing ribs 23 are formed on the surface 25 in a sawtooth-like manner, and the distance between two adjacent fixing ribs 23 is adjusted to the thickness of the heat sink 16 measured in the opening 17 (see Figure 1) in order to securely fix it. Thus, with the support legs 21 and 22, the support pin 20 is held in the desired position on the carrier 13, i.e. the heat sink 16 is fixed to the component 14, more precisely to its heat-generating part. In this regard, we refer to the fact known to those skilled in the art that between the heat sink 16 and the heat generating part 15, several layers of heat-conducting material serving to enhance heat transfer, such as commercially available pastes, elastomeric plates, silicone pastes, etc., can also be used. Turning to Figure 3, a support pin 30 has a rectangular cross-section, optionally a square cross-section, and is fixed perpendicularly to the support legs 31, 32 at their junction. The support pin 30 has fixing ribs 33 formed in a sawtooth-like manner, but these are not now located in the direction of the junction of the support legs 31 and 32, i.e. diagonally to the cooling fin, but extend in a substantially vertical plane parallel to the longitudinal axis of the support leg 31. A third possible design of the support pin 40 is shown in Figure 4. The figure shows support legs 41, 42, which here also extend at right angles to each other, and the support pin 40 is attached to them at their intersection. The support pin 40 is cylindrical in design to illustrate the diversity of the solution and has fastening ribs 43 running around it as a collar. The support pin 40 is connected to the connection region of the support legs 41, 42 via a flange 44 with a diameter exceeding its diameter at the bottom, and the support pin 40 is connected to the support legs 41, 42, for example, by means of the flange 44, but it is noted here that the flange 44 provides a sufficient surface area for the support pin 40 to be attached directly to the carrier 13, for example by gluing. The role of the flange 44 is essential because the support pin 40 must be relatively thin and of small diameter to ensure its flexibility. The support pins 11, 12 can be made of metal or plastic, but an essential condition is that each support pin 11, 12 must be flexible in order to be easily connected to the lower heat sink or, by bending in its openings 17, to enable the heat sink 16 to be pulled off the support pins 11, 12. Accordingly, each of the support pins 20, 30, 40 shown in Figures 2, 3, and 4 must also be flexible and can be made of any material that provides the desired flexibility. The support pins 20, 30, 40 clamp the cooling fin with sufficient force, i.e., they are actually fixed by means of a force-locking connection, and the fixing ribs 23, 33, 43 only serve to increase this frictional force. Another important feature is the arrangement of the support pins 11, 12 relative to the carrier and the heat sink 16: according to the design shown in Figure 1, the support pins 11, 12 are arranged diagonally relative to the component 14, and in all cases where only two support pins 11, 12 are sufficient to secure the heat sink, the support pins 11, 12 are arranged in this way. The specific design of the support pins 11, 12 can be any of those shown in Figures 2, 3, 4, since each support pin 20, 30, 40 is suitable for holding the heat sink 16 in the opening 17 formed in it and ensuring the necessary thermal connection between the heat sink 16 and the heat generating part 15 of the component 14. However, if four support pins 11, 12 must be used due to the required strength or some sensitive component, then the embodiment shown in Figure 5 can be used. In Figure 5, four support pins 50, 51, 52 and 53 are shown, which are located at each corner of a rectangular frame 54. The specific design of the support pins 50-53 can be any of those previously described, and it is not even necessary to assign four support pins 50-53 of the same design to a single frame 54. The retaining pins 50-53 are designed to fit, be clamped into, the cylindrical holes, notches, slots or any other suitable shaped openings 55 and 56 of the heat sink 57 (two of the four can be seen in the figure). HU 221213Β1 lake). In some cases, the support pins 50-53 are not formed vertically, but slightly apart from each other or slightly closer together, which further increases the force with which the heat sink 57 is fixed in the openings 55, 56 of the heat sink 57. In the embodiment shown in Figure 6, it can be observed that if greater force is required, or for some reason it is not possible to form openings of some shape in the heat sink 66, the ends of the support pins 50-53 can be accommodated by fastening plates 60,61 extending through the heat sink 66, in the region of the ends 62, 63,64 and 65 of which openings of appropriate size and shape (not shown in the drawing) are formed to accommodate the ends of the support pins 50-53. The fastening plates 60, 61 extend on the heat sink 66, between its ribs 67, and fix it to the heat generating part 15 with a force-locking connection as described earlier. This can be accompanied by the use of the frame 54 shown in Figure 5 to ensure the sufficient clamping force and, through it, the desired good thermal connection. However, there may be situations where a frame, such as frame 54 shown in Figure 5, presents an obstacle, for example, a component 14 is too large to fit in frame 54, or is otherwise undesirable. In this case, the support pins 50-53 are not secured to frame 54, but directly to carrier 13. Figure 7 shows a further possible embodiment in side view. The retaining pins 70, 71 of the fixing assembly according to any of the previously described designs are connected to the supporting legs 72, 73 and may even stand slightly together. At least one fixing plate 74 is assigned to the retaining pins 70, 71, the ends of which have openings suitable for receiving the retaining pins 70 and 71. In the illustrated case, the ends of the fixing plate 74 have bends 79a, 79b, so that the fixing plate 74 presses the heat sink 75 onto a flatter component 76 and its heat generating part 77 in the position shown in the figure, or by turning the fixing plate 74, the same heat sink 75 can be pressed onto a higher component 76 and its heat generating part 77. The mounting assembly shown in Figure 7 eliminates the need to form openings or holes or other mounting elements in the heat sink 75, and similarly eliminates the need to pre-form a hole or opening in the carrier 78. Our invention provides greater freedom in the selection and arrangement of components than before. For example, in Figure 8, a significantly larger heat sink 82 can be attached to a smaller component 83 and its heat generating part 84 using the retaining pins 80, 81. A further difference compared to the solutions described so far is that the retaining pins 80, 81 extend into blind holes machined into the bottom of the heat sink 82, not visible in the side view of the figure. The retaining pins 80, 81, either alone or together with another retaining pin not visible in the figure, ensure the proper attachment of the large heat sink 82, usually arranged symmetrically, for example in one corner of the heat sink 82. In the embodiment shown in Figure 8, we can also see that a component 83 with a larger horizontal extent may have a heat generating part 84 with a smaller horizontal extent, or vice versa, but this does not play a role in the method of attaching the heat sink 82. The point is that the heat sink 82 rests on the heat generating part 84 of the component 83, and the component 83 is located on the carrier 85. The invention has been described so far with the aid of some embodiments which we consider advantageous. Based on the description, it will not be difficult for a person skilled in the art to design a heat sink mounting assembly which differs in details from those presented by us, but such designs are to be considered to fall within the scope of protection set out in the patent claims.

Claims

PATENT CLAIMS 1. Heatsink fixing assembly for electronic components, which has elements for positioning the heatsink (16) in the heat-generating part (15) of the electronic component (14) in a way that ensures heat dissipation by heat transfer, where the elements are the carrier (13) holding the electronic component (14) are designed as flexible support pins (11, 12) extending at a predetermined angle to their plane, one end of which is in a force-locking connection with the heat sink (16) that secures the position ensuring heat transfer between the heat sink (16) and the heat generating part (15) of the component (14), with characterized in that the other end of the support pins (11, 12) is mountable on the surface of the carrier (13).

2. The fixing assembly according to claim 1, characterized in that the fixing ribs (23, 33, 43) are in a force-locking connection with the cooling fin (16).

3. Fixing assembly according to claim 1, characterized in that the support pins (11,12) are made of plastic.

4. Fixing assembly according to claim 1, characterized in that the support pins (11,12) are made of plastic containing metal parts necessary for soldering.

5. Fixing assembly according to claim 1, characterized in that the support pins (11, 12) are made of metal.

6. The fixing assembly according to claim 1, characterized in that it contains four support pins (11, 12) arranged symmetrically in a square shape on the surface of the carrier (13).

7. The fixing assembly according to claim 1, characterized in that the support pins (11, 12) are connected to the supporting elements fixed on the surface of the carrier (13) and extending in a square shape.

8. Fastening assembly according to claim 1, characterized in that a layer of heat-conducting material is arranged between the heat-generating part (15) of the component (14) and the cooling fin (16).

9. Fixing assembly according to claim 8, characterized in that the heat-conducting material layer is a heat-conducting paste. HU 221 213 Β1 10. The fixing assembly according to claim 1, characterized in that the cooling fin (16) contains at least two openings (17) mechanically connected to the flexible support pins (11, 12).

11. The fixing assembly according to claim 1, characterized in that the support pins (11, 12) are made of plastic and contain fixing ribs (23, 33, 43) at their ends mechanically connected to the cooling fin (16).

12. The fixing assembly according to claim 1, characterized in that the support pins (11, 12) are made of metal that enables a soldering connection to the support elements attached to the surface of the carrier (13).