US20110100598A1

US20110100598A1 - Cooling arrangement

Info

Publication number: US20110100598A1
Application number: US12/916,896
Authority: US
Inventors: Frank Gõmmel; Bernd Rexhãuser; Ralf Baier
Original assignee: Lear Corp
Current assignee: Lear Corp
Priority date: 2009-10-30
Filing date: 2010-11-01
Publication date: 2011-05-05
Also published as: DE102009044368A1; CN102186326A; DE102009044368B4

Abstract

The invention relates to an arrangement for cooling at least one electrical and/or electronic component and/or group of electrical/electronic components by means of a cooling body. The cooling body demonstrates at least one recess into which the electrical/electronic component and/or the group of electrical/electronic components to be cooled can be inserted. Introduced into the recess of the cooling body is a medium, which nearly completely surrounds the at least one electrical/electronic component and/or the group of electrical/electronic components in their state of insertion into the recess.

Description

The invention relates to an arrangement for cooling at least one electrical and/or electronic component and/or group of electrical/electronic components by means of a cooling body.
There are a large number of arrangements for cooling electronic components with a cooling body. Thus for example, a cooling body for power electronic components is known from EP 1 732 131 B1. The connection of the components to the cooling body is accomplished by shaping the cooling body so that the shape of the cooling body matches the shape and position of the components to be cooled, which are arranged on a printed circuit board, and at least partially surrounds them. A heat transfer paste, which is used for heat transmission from the components to the cooling body and also guarantees a certain distance between the cooling body and component inside the protrusion, can be introduced into the protrusion. A disadvantage of this embodiment, however, is that spacer beads, which can easily be displaced during installation and in operation and can easily bring about a short circuit between the component and cooling body in this manner, are present in the cooling paste. Furthermore, this invention can cool only components which are arranged resting on a printed circuit board. In addition, this arrangement is not able to provide thermal cooling of a component all-around, so that a portion of the waste heat continues to be dissipated to the circuit board. Moreover, a boring filled with gel must be arranged to reduce the thermal gradient between the top and bottom sides. But the essential disadvantage is that a large portion of the heat of the component continues to be dissipated to the circuit board.
A cooling body for an electronic device for cooling electronic components is known from U.S. Pat. No. 5,315,480. In this invention, the cooling body is attached to a printed circuit board to which electronic components are fastened. The cooling body is placed on the components to be cooled and, in this connection, the cooling body can be appropriately fit to the components, for example the cooling body can demonstrate depressions or corresponding forming. The cooling body consists of a first insulating layer and a second layer that cools the component. In this method, a cooling body surrounds the components. It relates to a conventional arrangement of cooling bodies on electrical/electronic components. The disadvantage of this invention is that a large portion of the heat from the electrical/electronic components is transmitted to the printed circuit board.
EP 0 340 520 discloses an arrangement for convective cooling of electronic components arranged on printed circuit boards. A cooling body that consists of two joined parts arranged over one another is used. The lower part of the cooling body is made of plastic-metal composite films and is placed on the components for cooling. Shapes which match the position and shape of the components and which are filled with a good heat-conducting flexible material are built into the cooling body for its placement onto the components. The top part of the cooling body consists of a plate which demonstrates structures with large surface on the side facing away from the components. In this embodiment, the cooling body again does not surround the component to be cooled in an all-around manner. Again, a major portion of the heat emitted by the components to be cooled is transmitted to the printed circuit board.
From EP 1 300 883 A2 there is known a cooling body which demonstrates recesses into which there is introduced a heat-conducting material that serves to improve the heat dissipation of the components to the cooling body. In this invention, however, a large portion of the heat emitted by the components is again transmitted to the printed circuit board itself.
A disadvantage in the known arrangements for cooling electrical/electronic components is that a large portion of the heat output generated by the electrical/electronic component is transmitted to the printed circuit board to which the electrical/electronic component is fastened and/or electrically interfaced, and the printed circuit board thus heats up considerably.
The object of the present invention is to exhibit an arrangement for cooling electrical/electronic components which prevents transmission of the emitted heat of the electrical/electronic component to the printed circuit board to which the electrical/electronic component is electrically interfaced.
This object is achieved on the basis of the characteristics of patent claim 1.
Advantageous embodiments of the invention arise on the basis of the further description, the dependent claims, and the figures of a concrete embodiment example and the associated description of the figures.
The arrangement according to the invention serves to cool at least one electrical and/or electronic component and/or a group of electrical/electronic components by means of a cooling body. To this end, the cooling body demonstrates at least one recess into which the electrical/electronic component and/or the group of electrical/electronic components to be cooled can be inserted. Introduced into the recess of the cooling body is a medium, which nearly completely surrounds at least one electrical/electronic component and/or the group of electrical/electronic components in their state of insertion into the recess.
Advantageous in the embodiment of the invention according to claim 2 is that the medium that is introduced into the recess in the cooling body is a heat transfer medium. The heat transfer medium is preferably liquid, viscous, gelatinous, colloidal or adhesive-like and has good thermal conductivity. But the heat transfer medium is electrically insulating, i.e. not electrically conducting, in case electrical isolation between the component and cooling body is required. If this electrical isolation between component and cooling body is not required, then an electrically conducting medium can also be used. The heat transfer medium introduced into the recess is displaced when the at least one electrical/electronic component and/or group of electrical/electronic components is inserted and surrounds the at least one electrical/electronic component and/or group of electrical/electronic components in their state of insertion into the recess. The heat transfer medium guarantees good heat dissipation from the at least one electrical/electronic component and/or group of electrical/electronic components and good heat transfer to the cooling body. The embodiment of the heat transfer medium as liquid, viscous, gelatinous, colloidal or adhesive-like guarantees on the one hand that the heat transfer medium will surround the at least one electrical/electronic component and/or group of electrical/electronic components nearly completely and all-around in their state of insertion into the recess so that a nearly optimum heat dissipation will occur. On the other hand, the embodiment of the heat transfer medium as a viscous, gelatinous, colloidal or adhesive-like medium will see to it that the heat transfer medium does not run out of the recess, but remain in it, e.g. by adhesion, and continue to surround the at least one electrical/electronic component and/or group of electrical/electronic components.
It is advantageous in the embodiment of the invention as per claim 3 that the at least one electrical/electronic component and/or group of electrical/electronic components are surrounded by a frame, wherein the frame prevents the at least one electrical/electronic component and/or group of electrical/electronic components from forming a short circuit by coming into contact with the cooling body in and/or on the recess when the at least one electrical/electronic component and/or group of electrical/electronic components are inserted into the recess of the cooling body and in their state of insertion into the recess. The frame surrounds the at least one electrical/electronic component and/or group of electrical/electronic components with positive fit and, if necessary, with non-positive fit, and thereby increases the stability of the at least one electrical/electronic component and/or group of electrical/electronic components. This increased stability is characterized by the fixation of the component. This is particularly advantageous during the soldering process, because it is possible to dispense with expensive measures such as mechanical devices to hold down the components.
In addition, the frame prevents the area of the at least one electrical/electronic component and/or group of electrical/electronic components that carries electrical potential from coming into contact with the cooling body during insertion into the recess. This prevents the formation of a short circuit.
It is advantageous in the embodiment of the invention as per claim 4 that the frame consists of non-conducting material, preferably plastic, and/or that the frame surrounds the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled on at least two edges with positive fit and/or non-positive fit and, and/or that the frame is connected to the printed circuit board and thus supports and protects the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled, and/or that the frame demonstrates an opening on the side facing toward or away from the printed circuit board into which opening the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled can be inserted into the frame, and/or that the inside of the frame demonstrates guiding mechanisms that can guide the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled during the insertion into the frame. Since the frame consists of non-conducting material, preferably plastic, a possible electrical short circuit is prevented. Since the frame surrounds the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled on at least two edges with positive and/or non-positive fit, good stabilization on and in relation to the printed circuit board is achieved. Since the frame is connected to the printed circuit board, the frame mechanically supports the connection between the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled and simultaneously protects this connection against externally acting forces so that the frame first of all compensatingly absorbs a mechanical force acting on the electromechanical connection between the printed circuit board and the at least one electrical/electronic component and/or group of electrical/electronic components. Since the frame has an opening on the side facing toward or away from the printed circuit board, the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled can easily be mounted into the frame. Since the inside of the frame has guiding mechanisms that can guide the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled during the insertion into the frame, it is possible to easily mount the at least one electrical/electronic component and/or group of electrical/electronic components.
It is advantageous in the embodiment of the invention as per claim 5 that the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled are connected at least electrically to a printed circuit board and arranged offset from the printed circuit board or fixed directly on the printed circuit board. The arrangement of the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled offset from the printed circuit board makes it possible to insert the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled sufficiently deep into the recess of the cooling body so that heat transfer medium encircles and surrounds them all-around.
It is advantageous in the embodiment of the invention as per claim 6 that the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled can be inserted into the recess of the cooling body in common with the printed circuit board with or without a frame. In this manner, it is possible to cool entire assemblies that are arranged on a printed circuit board. In addition, SMD components arranged on a printed circuit board can also be cooled.
It is advantageous in the embodiment of the invention as per claim 7 that the printed circuit board can be fastened on the cooling body and that an air gap remains between the circuit board and the cooling body when the printed circuit board is on the cooling body in its fastened state, so that a temperature transmission from the cooling body and the at least one electrical/electronic component and/or group of electrical/electronic components to be cooled to the printed circuit board is largely prevented. The printed circuit board is thus freed from the influence of temperature. The printed circuit board is no longer heated by the heat emission of a component and/or group of components arranged thereon. It is therefore also possible to arrange temperature-sensitive elements on this printed circuit board.
In another advantageous embodiment of the invention, the cooling body demonstrates spacers which are disposed at least on the side facing the printed circuit board and upon which the printed circuit board comes to rest. These spacers prevent extensive contact between the cooling body and the printed circuit board, thereby preventing heat dissipation from the cooling body to the printed circuit board. Since an air gap forms between the printed circuit board and the cooling body, there is thermal insulation between the printed circuit board and the cooling body. At the same time, the effective area of the cooling body for heat dissipation to the ambient air is increased.

In the further description below, other characteristics and details of the invention will be described on the basis of concrete embodiment examples in connection with the drawings. The characteristics and interrelationships described in the individual variants can basically be transferred to all embodiment examples. The invention is not restricted to one of the following concrete embodiment examples or of the following embodiment example. In the description of the figures, the same reference characters are used for identical elements in the all figures. This serves for better comprehensibility of the invention.

The drawing shows:

FIG. 1 a longitudinal section through an arrangement according to the invention with frame,

FIG. 2 a top view on an arrangement according to the invention with frame,

FIG. 3 an electronic component with frame arranged on a printed circuit board,

FIG. 4 an electronic component with frame arranged on a printed circuit board,

FIG. 5 an electronic component with frame arranged on a printed circuit board,

FIG. 6 a component with a surrounding frame,

FIG. 7 a frame in side view,

FIG. 8 another view of a frame,

FIG. 9 the schematic representation of a cooling body according to the invention in longitudinal section,

FIG. 10 the schematic representation of a longitudinal section through an arrangement according to the invention without frame (no insulation)—before assembly,

FIG. 11 the schematic representation of a longitudinal section through an arrangement according to the invention,

FIG. 12 the schematic representation of another longitudinal section through an arrangement according to the invention for SMD with printed circuit board,

FIG. 13 the schematic representation of another longitudinal section through an arrangement according to the invention with frame for spacing/insulation before assembly,

FIG. 14 the schematic representation of another longitudinal section through an arrangement according to the invention with frame after assembly.

FIG. 1 depicts a longitudinal section through an arrangement according to the invention. It depicts the cooling body 2 in longitudinal section. The cooling body 2 demonstrates corresponding recesses for the enlargement of its surface. A recess 3 is built into the cooling body 2 on the side facing the printed circuit board 7. The recess 3 approximately corresponds to the shape of component 1 to be cooled, which is to be cooled by means of the cooling body. The component to be cooled can relate, for example, to a power transistor or an integrated circuit. Component 1 is electrically connected to a printed circuit board 7 and, in FIG. 1, is vertically distant from it, i.e. component 1 is connected only by a simple, thin mechanical connection, which preferably can be realized alone by the electrical terminals of component 1 or alternatively is a special recess in component 1, in order to form a mechanical connection with the printed circuit board 7. A heat transfer medium 4 is introduced into recess 3. The heat transfer medium 4 is preferably liquid, viscous, gelatinous, colloidal or adhesive-like and has good thermal conductivity. But at the same time, the heat transfer medium is not electrically conducting. The heat transfer medium 4 must be introduced into recess 3 before the component 1 to be cooled is mounted, wherein component 1 may relate to a single component, a group of components, an integrated circuit or a printed circuit board with a plurality of electrical/electronic components disposed thereon.
The heat transfer medium is introduced into recess 3. Component 1, which is arranged on the printed circuit board, is now inserted into recess 3. When component 1 is inserted into recess 3, component 1 displaces the heat transfer medium 4 situated in recess 3 so that the heat transfer medium 4 surrounds it all-around when component 1 is in its inserted state in recess 3. In an advantageous embodiment, the amount of heat transfer medium 4 in recess 3 is dosed in such a manner that the heat transfer medium 4 forms a slight superelevation vis-à-vis printed circuit board 7 at the opening of recess 3 when component 1 is in its inserted state in recess 3, so that the heat transfer medium 4 surrounds component 1 completely and all-around within recess 3. In another advantageous embodiment of the invention, the heat transfer medium 4 is chosen so that it remains in recess 3 and adhesively adheres when the cooling body 2 is tipped over or turned over.
In another advantageous embodiment of the invention, the heat transfer medium 4 hardens and thus simultaneously fixes the component in recess 3.
In another advantageous embodiment, a frame 5 surrounds component 1. Frame 5, which surrounds component 1 and, in a preferred embodiment, is mechanically connected to the printed circuit board 7, guarantees a stable connection between component 1 and printed circuit board 7. The frame 7 is also embodied so that it prevents the component 1 from coming into contact with the cooling body 2 when component 1 is inserted into the recess 3. This prevents a short circuit during the electrical commissioning of component 1.
In the inserted state of component 1 into recess 3, the printed circuit board 7 comes to rest on elevation points 11 of cooling body 2. An air gap 12 will remain between the printed circuit board 7 and cooling body 2 through skillful choice of elevations 11 of cooling body 2. The air gap 12 prevents an all-around and large transfer of heat from cooling body 2 and/or from component 1 to the printed circuit board 7.
The all-around envelopment of component 1 with heat transfer medium 4 in recess 3 provides for an extensive transmission of the heat production of component 1 to the cooling body 2. Since the binding of component 1 to the printed circuit board 7 is small in terms of volume and area, the printed circuit board 7 is almost entirely decoupled from the heat emission of component 1.
FIG. 2 depicts a top view onto the printed circuit board 7, which rests on the cooling body 2 and elevation 11. It is evident that component 1 has electrical connections to the printed circuit board 7 and that the frame 5 is mechanically connected to the printed circuit board 7.
FIG. 3 depicts an embodiment of a frame 5. Frame 5 is mechanically connected to the printed circuit board 7 by anchor points. The frame 5 preferably consists of plastic and/or non-conducting material. In another embodiment, the frame may also be manufactured of metal or metallic materials. But then it is necessary to take extra precautions that no electrical connection will exist between the frame 5 and component 1. The frame 5 provides for the stabilization of component 1 on printed circuit board 7 and also makes it possible to arrange component 1 on and slightly offset from printed circuit board 7.
FIG. 4 depicts another view of frame 5 on printed circuit board 7. The component 1 is set within the frame 5. Frame 5 contains guiding mechanisms 10 which guide component 1 when it is inserted into the frame 5.
In another embodiment of the invention, frame 5 is attached directly onto component 1 in a separate work step.
FIG. 5 provides another view of frame 5 with component 1 fastened therein. Frame 5 is mechanically connected to printed circuit board 7. Component 1 is electrically connected to the printed circuit board by terminals 15. FIG. 5 illustrates the anchor points 14 between the printed circuit board 7 and frame 5. The terminals 15 of component 1 are electrically connected to the printed circuit board 7.
FIG. 6 depicts another frame 5 with the component 1 inserted, the shape of frame 5 being very evident. Moreover, the electrical terminals 15 of the component, by means of which component 1 is electrically connected to the printed circuit board 7, are very recognizable.
FIGS. 7 and 8 depict various views of the frame 5 without component 1. It is very evident that there are frame recesses 16 through which the electrical terminals 15 of component 1 are guided when same is inserted into the frame 5. The anchor points 14 are embodied in the shape of a hook. The frame 5 can thus be connected to the printed circuit board 7 by means of a clip fastener, which then projects into the opening provided on the printed circuit board. In an advantageous embodiment, the frame 5 also demonstrates feet 17, which support the frame 5 on the printed circuit board 7 when the frame 5 is put into or onto the printed circuit board 7.
FIG. 9 depicts a longitudinal section through a cooling body 2. The recess 3 is built into cooling body 2. The recess 3, for example, is built into the cooling body in the form of a blind hole bore or else a quadratic or rectangular countersinking. A defined amount of heat transfer medium 4 is introduced into the recess 3, by means of a silk-screen technique for example, or by injection. The respective elevations 11, which guarantee that the printed circuit board 7 (not illustrated in FIG. 9) does not rest directly on the cooling body 2, are arranged on the cooling body 2.
FIG. 10 depicts the cooling body 2. It is illustrated in the state in which a printed circuit board 7 is introduced onto the cooling body 2 and component 1 is introduced into the recess 3 within which the heat transfer medium 4 is situated, wherein component 1, which in the embodiment as per FIG. 10 is arranged standing vertically on the printed circuit board 7, is mounted on the printed circuit board.
FIG. 11 depicts the printed circuit board 7 with the component 1 arranged standing upon the printed circuit board 7. Component 1 is introduced into the recess 3 of the cooling body 2. The elevations 11 of the cooling body 2 hold the printed circuit board 7 at a defined distance to the cooling body 2. An air gap 12 forms between the cooling body 2 and printed circuit board 7. The heat transfer medium 4, which is present in the recess 3, is displaced by the insertion of component 1 and now surrounds component 1, which is almost completely inserted into recess 3, all-around. This ensures a good heat transfer from component 1 to the heat transfer medium 4 and across the heat transfer medium 4 to the cooling body 2.
FIG. 12 again depicts a longitudinal section through a cooling body 2. The recess 3 is again built into the cooling body 2. In FIG. 12, a component 1, an SMD component in this embodiment, is mounted directly on the printed circuit board 7. The component 1 is jointly introduced into the recess 3 with the printed circuit board 7. The heat transfer medium 4, which was already present in the recess 3 before the introduction, will now surround the component 1 with the printed circuit board 7 in the recess 3. There is an all-around cooling of component 1 together with printed circuit board 7.
In FIG. 13, the component 1 is also arranged directly on a printed circuit board 7. The frame 5 surrounds component 1 and especially the electrical terminals 15. Frame 5 guarantees that there will be no contact between component 1, especially the potential-carrying and/or electricity-conducting parts of component 1, and the cooling body 2 during the introduction and placement of component 1 into the recess 3.
FIG. 14 depicts the arrangement of FIG. 13 in such a manner that the component 1 is introduced into the recess 3 of cooling body 2 together with the surrounding frame 5. The heat transfer medium 4 now surrounds the frame 5 and the component 1 all-around. The printed circuit board 7 comes to rest on the elevations 11 of cooling body 2 and the air gap 12 develops between the printed circuit board 7 and cooling body 2.

LIST OF REFERENCE CHARACTERS

- 1 component
- 2 cooling body
- 3 recess
- 4 medium (heat transfer medium)
- 5 frame
- 7 printed circuit board
- 9 opening
- 10 guiding mechanism(s)
- 11 elevation
- 12 air gap
- 14 anchor point
- 15 terminals
- 16 recess
- 17 feet

The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.

Claims

1-7. (canceled)

8. An arrangement for cooling at least one electronic component by means of a cooling body characterized in that the cooling body demonstrates at least one recess into which the electronic component to be cooled can be inserted and that a medium, which nearly completely surrounds the at least one electronic component in their state of insertion into the recess, is introduced into the recess.

9. Arrangement according to claim 1, characterized in that the medium is a heat transfer medium, that the heat transfer medium is liquid, viscous, gelatinous, colloidal or adhesive-like, and that the heat transfer medium has good thermal conductivity.

10. Arrangement according to claim 1, characterized in that the at least one electronic component to be cooled is connected at least electrically to a printed circuit board and arranged offset from the printed circuit board or fixed on the printed circuit board.

11. The arrangement according to claim 10, characterized in that the at least one electronic component to be cooled can be inserted into the recess of the cooling body in common with the printed circuit board.

12. Arrangement according to claim 11, characterized in that the printed circuit board is adapted to be fastened on the cooling body such that an air gap remains between the printed circuit board and the cooling body.

13. Arrangement according to claim 1, characterized in that the at least one electronic component is surrounded by a frame, wherein the frame prevents the at least one electronic component from forming a short circuit by coming into contact with the cooling body when the at least one electronic component is inserted into the recess of the cooling body and in the state of insertion of the at least one electronic component into the recess.

14. Arrangement according to claim 13, characterized in that the at least one electronic component to be cooled is connected at least electrically to a printed circuit board and arranged offset from the printed circuit board or fixed on the printed circuit board.

15. Arrangement according to claim 14, characterized in that the printed circuit board is adapted to be fastened on the cooling body such that an air gap remains between the printed circuit board and the cooling body.

16. Arrangement according to claim 14, characterized in that the frame consists of non-conducting material, the frame surrounds the at least one electronic component to be cooled on at least two edges, the frame is connected to the printed circuit board and supports the at least one electronic component to be cooled.

17. The arrangement according to claim 16, characterized in that the frame demonstrates an opening into which the at least one electronic component to be cooled can be inserted into the frame, and that the inside of the frame demonstrates guiding mechanisms that guide the at least one electronic component to be cooled during the insertion into the frame.

18. The arrangement according to claim 17, characterized in that the opening is on a side of the frame facing away from the printed circuit board.

19. The arrangement according to claim 17, characterized in that the opening is on a side of the frame facing toward the printed circuit board.

20. Arrangement according to claim 17, characterized in that the printed circuit board is adapted to be fastened on the cooling body such that an air gap remains between the printed circuit board and the cooling body.

21. The arrangement according to claim 18, characterized in that the at least one electronic component to be cooled can be inserted into the recess of the cooling body in common with the printed circuit board.