DE102014201032A1 - Electric control unit, transmission with an electric control unit and method for producing an electrical control unit - Google Patents

Abstract

The invention relates to an electrical control unit and a transmission with an electrical control device comprising a circuit carrier (4) having a first surface (4a) and a second surface (4b) opposite the first surface (4a), at least one surface (4a, 4b ), at least one electrical component (7, 8) is arranged, wherein the circuit carrier (4) in a mold housing (3) is arranged from a molding compound and wherein at least one electrical component (7) is associated with a heat conductor (6) for the removal of heat from the at least one electrical component (7) to the environment and wherein the heat conductor (6) from a circuit carrier (4) facing away from the surface (7a) of the electrical component (7) through the mold housing (3) to the outside of the mold housing (3) is guided and a manufacturing method for an electrical control unit.

Description

The present invention relates to an electrical control device, in particular to an electrical control device with a directed heat dissipation of heat-generating electrical components and to a transmission with such a control device and to a method for producing such a control device.

Electrical control units are used in a wide variety of applications. One area of application for controllers is found e.g. in motor vehicles as transmission control units again. These controllers are often subject in their operation thermal and / or mechanical loads. To protect the ECU electronics from the environment, especially against electrically conductive and aggressive media, the circuit elements are in a housing.

From the DE 10 2011 083 002 A1 is known a Mold housing, in which a circuit carrier and its electronics can be included. In such mold housings, however, because of the hot components, such as, for example, MOSFETs, semiconductors, etc., in operation mode, rapid generation of heat due to waste heat of the components can quickly occur. The heat development of the electronic components is distributed to the circuit board and the molding compound. The circuit board and the molding compound expand due to the heating. In order to ensure uniform thermal expansion of the printed circuit board and the mold housing and to prevent damage to the mold housing, a type of symmetrical arrangement of the printed circuit board and its components in the molding compound is described.

The JP 2003115681 discloses an electronic arrangement, wherein individual heat-producing elements are arranged on a cooling plate and the cooling plate protrudes at least partially from the extrusion coating, whereby the heat of the extrusion coating can be led out.

The JP 2001237353 shows a molded on one side populated circuit board whose circuit board is connected via Wärmeleitpins to the outside environment.

The invention has for its object to provide a technique for the improved dissipation of heat from a device. The invention achieves this object by means of an electronic control device and a method having the features of the independent claims. Subclaims give preferred embodiments again.

An electrical control device according to the invention comprises a circuit carrier having a first surface and a second surface opposite the first surface, wherein at least one electrical component is arranged on at least one surface and wherein the circuit carrier is arranged in a mold housing of a molding compound. Furthermore, it comprises a heat conductor assigned to at least one electrical component for removing heat from the at least one electrical component to the environment. The heat conductor is designed such that it is guided by a circuit carrier remote from the surface of the electrical component through the mold housing to the outside of the mold housing.

With the arrangement according to the invention, in the case of a closed mold housing, the heat of the electronic components within the mold housing can be dissipated to the outside. Due to the rapid heat dissipation in the heat conductors prevents the mold housing absorbs the heat emitted by the electronic components and cause it due to the low heat conduction of the mold housing to its damage. With the arrangement according to the invention it is achieved that the heat is distributed homogeneously and thereby it can not lead to different heating and expansion of the circuit board and / or the mold housing. Damage to the housing e.g. Crazing, are avoided. Consequently, it is ensured that the mold housing is media-tight and avoided that oil could creep to the electrical components.

With the arrangement according to the invention it is achieved that the heat of the electronic components is not absorbed by the circuit board or passed through the circuit board to a heat sink, but that the heat is passed directly through a heat conductor to the outside, ie to a heat sink outside the mold housing. This prevents the circuit board from being inadvertently expanded by the thermal stress and disproportionately from the molding compound.

A heat conductor is characterized in that it transports heat from a first location to a second location, the heat always flowing in the direction of the lower temperature according to the second law of thermodynamics. A good conductor of heat is in this case e.g. a metal. The material and the dimension of a heat conductor can be adapted to the expected heat flow.

A mold housing refers to a housing which has been produced by an encapsulation process or by a potting process. Moldings are in particular by the encapsulation or Vergießung a circuit board by means of a Thermosets or a thermoplastic formed. However, mold housings also designate housings for, for example, a printed circuit board, which are characterized in that a printed circuit board primarily has a thermoset coating which is surrounded by a secondary thermoplastic encapsulation.

The environment here refers to the area outside of the electrical control unit.

In one embodiment of the invention, the heat conductor is in thermal contact with the electrical component and abuts against the surface of the electrical component. As a result, an optimal heat transfer between the surface of the electrical component and the heat conductor is ensured.

In a further embodiment of the invention, the heat conductor is at a distance from the surface of the electrical component and is in thermal contact with the electrical component via a heat-conducting medium present in the region between the electrical component and the heat conductor. This ensures that the heat conductor exerts no force on the electrical component, which could lead to possible damage to the component. On the other hand, the heat-conducting medium, which ideally has elastic properties, ensures that optimum heat transfer is present between the surface of the electrical component and the heat conductor.

In a further embodiment of the invention, the heat conductor is connected to a heat sink for emitting heat to the environment and the heat sink is spaced from the mold housing or at least partially against the mold housing. As a result, the area is increased with the heat emitted by the electrical components to the environment, whereby the heat transfer to the outside of the mold housing can be increased. At the same time it is ensured that the heat sink does not give off heat to the mold housing, whereby it is unnecessarily heated.

In a further embodiment of the invention, the heat conductor is connected to a heat sink for emitting heat to the environment and the heat sink is at least partially surrounded by the mold housing. This ensures that the overall height of the electrical control unit is reduced.

A heat sink is a spatially limited area or body that delivers stored or supplied thermal energy to an adjacent medium outside of the electrical controller. Adjacent media may be solid objects, liquids, e.g. Oil or gases, e.g. Be ambient air. The heat sink may in particular be a metal plate.

Suitably, the heat conductor and the heat sink are integrally formed. But it is also possible that the heat conductors are screwed or used in the form of heat pins to the heat sink.

In a further embodiment of the invention, the heat conductor in the region of the mold housing on its circumference executed surveys and / or cuts. As a result, an optimal connection between the heat conductor and molding compound is achieved. The elevations and / or cuts in the heat conductor results in a good stability of the heat conductor in the molding compound. Suitably, the elevations and / or cuts in the heat conductor can be achieved by roughening the surface of the heat conductor.

In a further embodiment of the invention, spacers are provided which are guided from a surface of the circuit carrier to the heat sink. These spacers may in this case be attached to the heat sink and rest on the surface of the circuit carrier or the spacers are fastened to the circuit carrier and serve as a support for the heat sink. The spacers are expediently designed such that they are longer than the heat conductors which are present between the heat sink and the electrical components on the circuit carrier. This essentially serves to ensure that the contact pressure of the injection molding tool on the heat sink is not conducted via the heat conductors to the electrical components when casting the circuit carrier.

In another embodiment of the invention, heat conductors are associated only with electrical components having an operating temperature above a predetermined threshold, e.g. 60 ° C have. As a result, the production cost is reduced, since only such electrical components, a heat conductor is assigned, which have a critical operating temperature, which can lead to thermal stresses within the mold housing or the circuit board.

• – Bereitstellen eines Schaltungsträgers mit einer ersten und einer der ersten Oberfläche gegenüberliegenden zweiten Oberfläche,
• – Anordnen mindestens eines elektrischen Bauelements an mindestens eine Oberfläche,
• – Positionieren von Wärmeleitern über wenigstens einem elektrischen Bauelement,
• – Vergießen des Schaltungsträgers mit einer Moldmasse, wobei die erste und zweite Oberfläche des Schaltungsträgers sowie ein Abschnitt des Wärmeleiters in direktem thermischem Kontakt mit der Moldmasse sind.

The method according to the invention for producing an electrical control device comprises the following method steps:

• Providing a circuit carrier with a first surface and a second surface opposite the first surface,
• Arranging at least one electrical component on at least one surface,
• Positioning heat conductors over at least one electrical component,
• - Potting the circuit substrate with a molding compound, wherein the first and second surfaces of the circuit substrate and a portion of the heat conductor are in direct thermal contact with the molding compound.

Suitably, the lengths of the individual heat conductors are adapted to the height of the individual electrical components, so that after the casting of the circuit substrate, the electrical control unit has the lowest possible height.

The invention will be explained in more detail with reference to figures. Show it

1 FIG. 2: a schematic representation of an electrical control unit with a housing and heat conductors connected to a heat sink, FIG.

2 - 5 : further schematic representations of an electrical control unit with heat conductors,

5 : Another schematic representation of an electrical control device with two opposing heat sinks.

1 shows an electrical control unit 1 with a circuit carrier 4 , eg a printed circuit board, with electrical components 7 . 8th which are on a first surface 4a of the circuit board 4 are arranged. The electrical control unit 1 has a mold housing 3 on which the circuit carrier 4 and the electrical components 7 . 8th completely surrounds. Some electrical components 7 . 8th are heat conductors 6 assigned by the mold housing 3 run and which in contact with the surface 7a , the electrical components 7 . 8th stand. A heat conductor 6 connects the surface 7a an electrical component 7 . 8th with an area outside the mold housing 3 , The heat conductors 6 are with a heat sink 5 , For example, a metallic Wärmeleitplatte or a cooling plate connected. The heat conduction plate 5 has cooling fins 9 can be discharged to increase the surface of the heat to the environment. This heat sink 5 lies on the mold housing 3 on. But it is also possible that the heat sink 5 from the mold housing 3 through a gap 16 is complained of ( 3 . 5 ).

1 shows that only individual electrical components 7 a heat conductor 6 assigned. Ideally, only such electrical components 7 , eg MosFets, semiconductors or freewheeling diodes a heat conductor 6 assigned, which have an operating temperature above a predetermined threshold, for example 60 ° C. The electrical components 8th which are not heat conductors 6 is assigned, their waste heat by heat spreading in the circuit board (PCB) 4 and partly about the molding compound 3 to distribute. The electrical components 8th which are not heat conductors 6 is assigned, for example, capacitors or chip components.

The main waste heat is thus directly over the expedient metallic executed heat conductors 6 discharged and to the surface of the molding compound 3 formed control unit 1 brought. On the surface, the heat conductors give 6 the heat to a heat sink 5 from. The heat sink 5 is about cooling fins 9 so that it offers the largest possible surface for heat distribution. 4 shows an electrical control unit 1 in which the heat conductors 6 from the mold mass 3 protrude and deliver the transported heat directly to the environment. This embodiment thus differs from the embodiments shown in the other figures in that in 4 no heat conduction plate 5 is available. This variant is to be preferred in particular when a low overall height and a low weight are required.

The heat conductors 6 can be designed for example as Wärmeleitpins. These pins 6 and the heat conduction plate 5 in which the pins 6 screwed, plugged, etc. may be made of a thermally conductive material. It is also conceivable that the heat conducting pins 6 and the heat conduction plate 5 can be designed as a one-piece component. This one-piece heat dissipating component is based on the nature of the printed circuit board 4 adapted to production technology, in particular to the height of the individual electrical components 7 ,

The molding compound 3 , which at the same time the housing 3 of the control unit 1 is preferably a thermosetting plastic, since its properties enclose metallic inserts very tight. So the oil can not over the Wärmeleitpins 6 to the sensitive electronic components 7 . 8th to crawl. For a better hold of the Wärmeleitpins 6 to ensure their surface 14 roughened or with rough elevations, as in 3 - 5 represented, provided. These surveys 14 form a kind of variety of barbs that use the heat conducting pins 6 still firmly with the Moldmasse 3 connect. Thus, the fixed positioning of the pins 6 , additionally guaranteed against external influences.

On the circuit board 4 are electrical contacts 10 attached for connecting the circuit board 4 with outside the electrical control unit 1 existing assemblies. This electrical contact 10 could also be a plug, etc. By a partially uninsulated area of the electrical connection 10 , in particular one Stranded wire, here too, ensures that the molding compound 3 meets the metal and thus prevents the creeping of the oil.

On the heat conduction plate 5 are additional spacers 11 attached, which on the surface 4a of the circuit board rest. These spacers 11 can also be made of a thermally conductive material and thus for cooling of the circuit substrate 4 serve. The spacers 11 are designed to be directly on the surface during the manufacturing process 4a of the circuit board 4 , ie next to the electronic components 7 . 8th be positioned. This ensures that during the manufacturing process no pressure on the heat conductors 6 on the electronic components 7 is exercised. The length of the heat conductor 6 over the electronic components 7 is expedient production technology adapted so that when assembling the circuit substrate 4 and the heat conducting plate 5 with attached heat conducting pins 6 and spacers 11 the heat-conducting pins 6 the surface 7a the electronic components 7 just touch or with a given distance 12 over the electronic components 7 lie ( 2 ).

2 shows such an embodiment in which the Wärmeleitpins 6 not directly on the hot electronic components 7 rest. For sensitive electronic components 7 can be a given distance 12 less than 1 mm between Wärmeleitpin 6 and component 7 be provided. That's the component 7 Protected against possible metallic vibrations and can by the small distance 12 the heat still on the Wärmeleitpin 6 dissipate. The molding compound 3 serves as damping. In addition, by the distance 12 formed space with a flexible heat transfer medium 13 , Eg be filled with a thermal grease.

For fixing the electrical control unit 1 on eg a hydraulic plate 15 are holders 2 present, which through the mold housing 3 are guided and the circuit carrier 4 with the hydraulic plate 15 connect. 1 shows that the hydraulic plate 15 a depression 15a in which the electrical control unit 1 can be introduced. As a result, a compact construction of a control device on, for example, a transmission part can be achieved. The hydraulic plate 15 This represents essentially a wall of a transmission.

5 shows an electrical control unit 1 with a circuit carrier 4 which is on the first surface 4a and on the second surface opposite the first surface 4b with electronic components 7 . 8th is equipped. Every surface 4a . 4b is a heat conducting plate 5 associated with which several heat conductors 6 is connected to the cooling of the respective associated electronic components 7 ,

6 shows the process steps for the production of an electrical control device. The method has the following method steps. In the first step 17 becomes a circuit carrier 4 with a first and a first surface 4a opposite second surface 4b provided. On at least one surface 4a . 4b this circuit carrier 4 will be in a second step 18 at least one electrical component 7 . 8th arranged. In the third step 19 become heat conductors 7 via at least one electrical component 7 positioned. In the fourth step 20 becomes the circuit carrier 4 with the molding compound 3 potted, with the first and second surface 4a . 4b of the circuit board 4 and a section of the heat conductor 6 in direct thermal contact with the molding compound 3 are.

LIST OF REFERENCE NUMBERS

1

electrical control unit

2

fastening device

3

Molded housing / molding compound

4

circuit support

4a

first surface

4b

second surface

5

heat conduction

6

heat conductor

7

electrical component

7a

Surface of the electrical component

8th

electrical component

9

cooling fins

10

electrical connection

11

spacer

12

Distance between electrical component and heat conductor

13

heat transfer medium

14

Surface of the heat conductor

15

hydraulic plate

15a

deepening

16

Distance between mold housing and heating plate

17

Step 1

18

step 2

19

step 3

20

Step 4

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011083002 A1 [0003]
• JP 2003115681 [0004]
• JP 2001237353 [0005]

Claims (11)

Electric control device comprising a circuit carrier ( 4 ) with a first surface ( 4a ) and one of the first surface ( 4a ) opposite second surface ( 4b ), wherein on at least one surface ( 4a . 4b ) at least one electrical component ( 7 . 8th ), wherein the circuit carrier ( 4 ) in a mold housing ( 3 ) is arranged from a molding compound and wherein at least one electrical component ( 7 ) a heat conductor ( 6 ) is assigned to the removal of heat from the at least one electrical component ( 7 ) to the environment, characterized in that the heat conductor ( 6 ) from a circuit carrier ( 4 ) facing away from the surface ( 7a ) of the electrical component ( 7 ) through the mold housing ( 3 ) to the outside of the Moldgehäuses ( 3 ) is guided. Electrical control device according to claim 1, characterized in that the heat conductor ( 6 ) in thermal contact with the electrical component ( 7 ) and on the surface ( 7a ) of the electrical component ( 7 ) is present. Electrical control device according to claim 1, characterized in that the heat conductor ( 6 ) from the surface ( 7a ) of the electrical component ( 7 ) and above, in the area ( 12 ) between the electrical component and the heat conductor existing Wärmeleitmedium ( 13 ) with the electrical component ( 7 ) is in thermal contact. Electrical control unit according to one of the preceding claims, characterized in that the heat conductor ( 6 ) with a heat sink ( 5 ) is connected to the dissipation of heat to the environment and the heat sink ( 5 ) of the mold housing ( 3 ) ( 16 ) is or at least partially on the mold housing ( 3 ) is present. Electrical control device according to one of the preceding claims 1-3, characterized in that the heat conductor ( 6 ) with a heat sink ( 5 ) is connected to the release of heat to the environment, and the heat sink ( 5 ) at least partially from the mold housing ( 3 ) is surrounded. Electrical control device according to claim 4 or 5, characterized in that the heat conductor ( 6 ) and the heat sink ( 5 ) are integrally formed. Electrical control device according to one of the preceding claims, characterized in that the heat conductor ( 6 ) in the region of the mold housing ( 3 ) surveys and / or cuts ( 14 ) having. Electrical control unit according to one of the preceding claims, characterized in that spacers ( 11 ), which from a surface ( 4a . 4b ) of the circuit carrier ( 4 ) to the heat sink ( 5 ) are guided. Electrical control unit according to one of the preceding claims, characterized in that heat conductors ( 6 ) the electrical components ( 7 ), which have an operating temperature above a predetermined threshold value. Transmission with an electrical control device according to one of the preceding claims, characterized in that the wall of the transmission has a recess ( 15a ) into which the electrical control unit ( 1 ) is introduced and fixed. Method for producing an electrical control device according to one of the preceding claims 1 to 9 comprising the following method steps: - providing a circuit carrier ( 4 ) with a first and a first surface ( 4a ) opposite second surface ( 4b ), - arranging at least one electrical component ( 7 . 8th ) to at least one surface ( 4a . 4b ), - positioning of heat conductors ( 6 ) via at least one electrical component ( 4a ), - Potting the circuit carrier ( 4 ) with a molding compound ( 3 ), wherein the first and second surfaces ( 4a . 4b ) of the circuit carrier ( 4 ) and a section of the heat conductor ( 6 ) in direct thermal contact with the molding compound ( 3 ) are.

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