EP3578017A1

EP3578017A1 - Control unit and method for production thereof

Info

Publication number: EP3578017A1
Application number: EP18702221.5A
Authority: EP
Inventors: Simon Green; Thomas Fellner; Udo Hennel; Matthias Lausmann; Stefan Doehren
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-02-01
Filing date: 2018-01-26
Publication date: 2019-12-11
Also published as: WO2018141641A1; DE102017201582A1

Abstract

The invention relates to a control unit (10), having a circuit carrier (11), on which at least one heat generating component (15) is arranged, wherein the circuit carrier (11) is covered, at least in regions, at least on the side facing the at least one component (15) by a plastic compound (42), having a plug connection element (12) for electrically contacting the circuit carrier (11), and having a cooling element (25), which is arranged in at least indirect operational connection to the at least one heat generating component (15).

Description

Description title

Control device and method for its production prior art

The invention relates to a control device according to the preamble of claim 1. Furthermore, the invention relates to a method for producing a

Control device according to the invention.

A control device with the features of the preamble of claim 1 is known from DE 10 2010 030 170 A1 of the applicant. The known control unit is characterized by a circuit carrier, on the upper side of which a plurality of (electronic) components are arranged. The circuit carrier is in turn connected to a wiring carrier in the form of coated flex films or a printed circuit board. The circuit carrier is from a

Frame element surrounded by a distance, which in turn with the

Wiring carrier is connected. Within the frame member, a plastic mass is arranged, which surrounds the circuit substrate with its components or covers and thereby protects. For heat dissipation by the heat generated by the components, the control device described so far can be connected to a heat sink as a cooling element, which is arranged in operative connection or in contact with the plastic compound and the frame member. Further details regarding the coupling of the controller to the

Heat sink and the formation of the heat sink can not be removed from the cited document.

Furthermore, it is known from EP 1 677 583 B1 to connect electrically conductive regions of the conductor foil to plug connections in the form of connection pins or similar elements of a plug connection element in the case of a flexible conductor foil. Disclosure of the invention

The control unit with the features of claim 1 has the advantage that the control unit in a particularly simple and elegant way to a

Carrier element can be attached. For this purpose, it is analogously provided that the cooling element not only serves to dissipate heat of at least one heat-generating component, but additionally at least indirectly as a fastening element for attaching the control device to a

Carrying member. For example, the support member may also be configured to form another heat path for dissipating heat, i. be thermally conductively connected to the cooling element. This is the case, for example, when the carrier element is part of a vehicle body. Thus, in particular, a particularly simple and mechanically advantageous design of the control device results because the control device is in an immediate

Coupling of the cooling element to a support element itself must absorb or transmit no forces or mechanical stresses during attachment to a support member, but only has to be ensured that a sufficiently strong connection between the control unit and the cooling element is present. This is therefore particularly advantageous because a standing for discussion cooling element, for example in the form of a

Aluminum existing, produced by extrusion profile section may be formed and thus has a relatively high strength or rigidity. In contrast, it may be provided in the control unit that the circuit carrier in the form of a flexible conductor foil or a flexible printed circuit board o.ä. is formed, so that a direct connection of the circuit substrate, for example, with a carrier element to a

Vehicle body requires additional, the construction cost, the size or the cost of the circuit board causing measures. However, the invention should also include the case in which the cooling element with a plug connection body or a plug connection element

mechanically firmly connected, for example, by a latching connection, wherein the plug connection body in turn serves the attachment to the support element. In this case, only an indirect attachment of the

Circuit carrier over the cooling element instead. However, even in this case, a lower mechanical load of the circuit substrate is possible. Advantageous developments of the control device according to the invention are listed in the subclaims.

A mechanically particularly good or firm connection of the control device to a carrier element is achieved when the cooling element laterally engages over the circuit carrier and in the out-of-cover with the circuit carrier sections has several attachment points for attachment to the support element. Such a design is therefore also useful or advantageous because then the cooling element has a relatively large extent (since it surmounted the lateral edge regions of the circuit substrate) and thus also allows a particularly good or effective heat dissipation. Preferred is an embodiment in which the cooling element is formed in cross section in approximately U-shaped, so that the circuit carrier can be arranged in the region between the short legs of the profile. From these short legs can in turn from the circuit carrier wegragende

Be formed sections provided with holes, by means of screws or similar fasteners of the attachment of the cooling element to the support member. A particularly safe and easy installation of the cooling element on the

Circuit carrier, which also allows the exact adjustment or positioning of the cooling element to the circuit carrier, provides that the

Cooling element by means of at least one spacer element with the

Circuit carrier is connected to form a latching connection. This spacer element may, for example, in the form of an injection molded part

Plastic consist of the one hand by its shape the defined or

desired distance between the circuit carrier and the cooling element adjusts, and on the other hand has the required locking elements in order to form the latching connection with the circuit carrier, for example in the region of a hole of the circuit carrier. It is also alternatively conceivable that the at least one spacer element consists of conductive material and is connected to the circuit carrier with low resistance. In this case, the cooling element is used in addition to EMC shielding. Instead of electrically conductive spacer elements, an electrical coupling between the circuit carrier and the cooling element or the like by metallic latching hooks. between the cooling element and the circuit carrier. Furthermore, it is preferably provided according to the invention that at least the intermediate space between the at least one heat-generating component and the cooling element is filled with the plastic compound. As a result, the transmission of the heat generated by the component via the plastic compound to the cooling element is ensured. Furthermore, a mechanical decoupling between the cooling element and the component is achieved. In addition, it is preferred that the cooling element is surrounded not only on the side facing the component of the plastic mass or is arranged in operative connection, but also on the side facing away from the component. As a result, an optimization of the heat input is effected in the cooling element and at the same time the cooling element against the influence of external media, such as moisture or the like, protected by the plastic compound. A further preferred embodiment of the control device described so far provides that the plastic mass consists of several plastic layers. In particular, it may be provided that the material of the plastic layers differs in their physical and / or chemical properties and / or their layer thicknesses. Thus, for example, the case is encompassed by the invention, in which at first a (first) plastic layer made of low-viscosity material is in operative connection with the

Circuit board or the components is arranged to fill any existing gap or take an underfill function on the components and at the same time electrical insulation of the components or the

To effect circuit carrier. By way of example, this first plastic layer is surrounded by a second layer of plastic consisting of highly viscous material, this plastic layer, for example, serving, in particular, to effect a mechanically good protection of the control device against external influences. For this purpose, it can also be provided, for example, that the plastic material of the second layer fillers or similar materials are added, either to increase the strength or other

physical properties, for example, for E MV shielding, for better thermal conductivity or, for example, for reasons of better manufacturability or an optimized manufacturing process. It is also possible that the plastic mass is colored to increase the thermal radiation of heat. Furthermore, it is explained that it is the coating with the Plastic mass may be locally limited, so that in particular (only) a thermal connection with the cooling element is achieved. In this case, it may be advantageous for the circuit carrier by a separate

Protect protective housing mechanically.

A first type of control device provides that the circuit carrier is designed in the form of a printed circuit board, and that contact pins of the

Plug connection element are connected by press-fitting and / or cohesive connections with electrically conductive areas of the circuit board (conductors). Such a cohesive connection consists in particular in the formation of solder joints.

Alternatively, it is also possible that the circuit carrier is designed in the form of a flexible conductor foil, and that electrically conductive surface regions of the conductor foil are electrically conductively connected to connection elements of the plug connection element.

The invention also includes a method for producing a control device according to the invention described so far. The method provides that the plastic mass is applied to the circuit carrier in the dipping process. The use of a dipping method has the particular advantage that, in contrast to the prior art mentioned in the introduction according to DE 10 2010 030 170 A1, a frame element connected to the circuit carrier or wiring carrier can be dispensed with, so that the control unit in the area of the circuit carrier has a particularly compact design Design has. In addition, it allows the dipping process in a particularly simple and elegant way, for example, at the same time to provide or cover the bottom and top of the circuit substrate with the plastic mass.

In development of the manufacturing process, it is envisaged that the

Plastic compound is applied by forming a plurality of plastic layers each in the dipping process with the interposition of at least one physical intermediate treatment on the circuit substrate. This physical intermediate treatment can be in the form of a

Heat treatment or UV curing of each last applied Plastic layer to optimize the manufacturing process or

to achieve desired properties of the individual plastic layers.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing.

1 shows a perspective view of a plug connection element of a control device connected to a circuit carrier in a pre-assembly step,

FIG. 2 shows the arrangement according to FIG. 1 in a cooling element mounted to the circuit carrier, likewise in perspective view, FIG.

Fig. 3 is a perspective view of a mounted on a printed circuit board

Spacer element, Fig. 4 is a longitudinal section of a fastening between the

Circuit carrier and the cooling element at the edge region of a printed circuit board,

Fig. 5 shows the arrangement of FIG. 2 after wrapping the

Circuit carrier with plastic mass in perspective view and

6 is a perspective view of a control unit, wherein the

Circuit carrier is designed in the form of a flexible conductor foil.

The same elements or elements with the same function are provided in the figures with the same reference numerals. In Fig. 1 during a pre-assembly step, a circuit substrate 1 1 and a plastic existing connector body or a Plug connection element 12 shown as part of a control unit 10. The controller 10 preferably, but not by way of limitation, is for use in a motor vehicle. The circuit carrier 1 1 is in the form of a known circuit board 14, and has on at least one side a number of components 15, wherein at least one of the components 15, during operation of the control unit 10 gives off heat from the area of

Control unit 10 is to be derived. The plug connection element 12 is mechanically firmly connected to the circuit carrier 11 or the circuit board 14 by means of technologies known per se, for example by means of a latching connection. Furthermore, the plug connection element 12, also in a known manner, not shown electrical connection elements in the form of connector pins, which is the at least indirect electrical

Contacting of the components 15 and an electronic circuit of the circuit substrate 1 1 serve. For this purpose, the connection pins are connected, for example via press-fit technology and / or integral connections with electrically conductive regions or conductor tracks of the circuit substrate 11.

Furthermore, the plug connection element 12 in the region of the two opposite side edges 16, 17 of the circuit board 14 on the

Components 15 on the upper side of the circuit board 14 side facing away from the connector element 12 in the direction of the circuit board 14 protruding latching hooks 18, of which in Fig. 1, only one latching hook 18 can be seen. The latching hooks 18 project beyond the respective side edge 16, 17 of the printed circuit board 14 with a latching hook section 19.

Furthermore, the circuit carrier 11 or the printed circuit board 14 is connected by way of example to eight spacer elements 20. In particular, the

Spacer elements 20 arranged approximately in the region of the heat-emitting components 15. The spacer elements 20 are components produced in the plastic injection molding process, which may be electrically conductive. The spacer elements 20 each have two elastically deflectable snap hooks 21, 22 (FIG. 3) projecting away from the printed circuit board 14. The spacer elements 20 serve to form a latching connection 24 with a cooling element 25. The cooling element 25, which can be seen particularly well in FIG. 2, is preferably designed as a section of an extruded profile and consists in particular of aluminum. The cooling element 25 engages over the printed circuit board 14 on the

Components 15 side facing up over both side edges 16, 17 away. The cooling element 25 has in the area between two side legs

26, 27 a U-shaped receptacle 28, in the region of the printed circuit board 14 is arranged or received. The side legs 26, 27 cooperate with the latching hook portions 19 of the plug connection element 12 and in particular prevent tilting of the cooling element 25 to the circuit board 14.

Depending on the constructive design, it can also be provided that a mechanically rigid or fixed connection, in particular a latching connection, is formed between the plug connection element 12 and the cooling element 25. In this case, it may further be provided that the

Plug connection element 12 of the attachment of the control unit 10 to a

Carrier element 40 is used.

Between the two side legs 26, 27, the cooling element 25 has a base portion 29 which in the area or in overlap with the

Spacer elements 20 each in cross section in approximately U-shaped, groove-like recesses 31 has. In the region of the recesses 31, the cooling element 25 cooperates with the snap hooks 21, 22 of the spacer elements 20 to form the latching connection 24. 4, the snap hooks 21, 22 cooperate with undercuts 32 in the region of the depressions 31. Furthermore, the base section

29 projecting from the circuit board 14, fin-like, arranged perpendicular to the plane of the circuit board 14 radiating surfaces 33 to increase the surface of the cooling element 25 on. On the side facing away from the base portion 29 side of the side legs 26, 27, the cooling element 25 each have a protruding from the circuit board 14 mounting portion 34, 35, for example, two through holes 36 for attachment of the cooling element 25 and thus also of the control unit 10 to a only symbolically represented surface of the

Carrier element 40 (Fig. 4). The attachment is preferably via mounting screws (not shown) For the production of the control unit 10, this is at least partially surrounded by a plastic mass 42 in the region of the circuit substrate 1 1 together with the pre-assembled cooling element 25. The

Plastic compound 42 consists of at least one, preferably a plurality of layers 43, 44 of plastic material, wherein the material of the individual layers 43, 44, in particular with regard to their viscosity, their chemical composition and other physical properties differs. For example, the first applied layer 43 may be made of epoxy resin.

In order to protect the circuit carrier 11 and the components 15 arranged on the circuit carrier 11, the circuit carrier 11 is provided with the plastic compound 42 or layers 43, 44 together with the cooling element 25 in at least one method step. It may be provided that the cooling element 25 is arranged either in direct contact with the at least one heat-emitting component 15, or preferably that between the heat-emitting component 15 and the heat-emitting component 15 side facing the

Cooling element 25, a gap 48 is formed (Fig. 3). The application of the layers 43,44 preferably takes place under a defined atmosphere

(For example, under a pressure of 1 Ombar to 50mbar).

When applying the plastic compound 42 or the layers 43, 44 to the circuit carrier 1 1, wherein the region of the plug connection element 12 is in particular only partially covered by the plastic compound 42, penetrates the plastic mass 42 in possibly between the components 15 and the

Circuit board 1 1 located gaps or gaps and fills these, for example, to the cooling element 25, so that this example, on the side facing away from the components 15 side is also at least partially covered by plastic material 42.

Between the application of the individual layers 43, 44 can

Intermediate treatment steps, in particular (pre-) curing steps can be provided. Such curing steps consist for example in the application of UV light for curing according to suitable plastic materials. The Plastic compound 42 and the layers 43, 44 effect in particular a mechanical protection of the circuit substrate 1 1 and a protection against ingress of media such as moisture in the region of the components 15, which affect the functioning of the control unit 10. After this

Applying the layers 43, 44 may be followed by a final curing in an oven.

In Fig. 5 it is shown that the plastic mass 42 with a high-viscosity layer 44, the circuit substrate 1 1 on the base portion 29 of the

Cooling element 25 opposite side partially surrounds, so that in particular can be dispensed with a separate housing. A low-viscosity layer 43 completely surrounds the circuit carrier 11.

FIG. 6 shows the case in which the circuit carrier 11 is designed in the form of a flexible conductor foil 45, on which the components 15 are arranged. In the illustrated embodiment are not only components 15 on the cooling element 25 and the base portion 29 facing side of the conductor foil 45, but also on the

Furthermore, it can be seen that a portion 46 of the conductor foil 45 is deformed approximately at right angles from the other regions of the conductor foil 45. In the region of section 46, electrically conductive surface regions 47 in the form of contact points which are electrically contacted with the connection pins arranged in the plug connection element 12 and not visible in FIG.

Regarding the use of plastic compound 42 is on the in the

Connection with the printed circuit board 14 Described reference.

The control unit 10 described so far can be modified or modified in many ways, without departing from the spirit of the invention. For example, it may be provided to use a flexible printed circuit board 14 instead of a flexible conductor web foil 45. It is also conceivable, for example, to apply only the (first) layer 43 by means of a dipping method, and possibly a further layer 44 in other methods. Also, the invention is generally not on exchange method for applying individual

Layers 43, 44 be limited. Rather, methods such as dipping,

Spraying, powder coating, the lamination of foils or the like conceivable.

Claims

claims

1 . Control device (10), with a circuit carrier (1 1), on which at least one heat-generating component (15) is arranged, wherein the circuit carrier (1 1) at least on the at least one component (15) side facing at least partially by a plastic material ( 42) is covered, with a plug connection element (12) for electrically contacting the circuit carrier (1 1), and with a cooling element (25) which is arranged in at least indirectly operative connection with the at least one heat-generating component (15), characterized in that the cooling element (25) is formed at least indirectly as a fastening element for fastening the control device (10) to a carrier element (40).

2. Control device according to claim 1,

characterized,

in that the cooling element (25) overlaps lateral edges (16, 17) of the circuit carrier (11) and has a plurality of fastening sections (34, 35) in the sections out of registration with the circuit carrier (11), which are designed to be connected to the carrier element (40) to be connected.

3. Control device according to claim 1 or 2,

characterized,

the cooling element (25) is connected to the circuit carrier (11) by means of at least one spacer element (20) to form a latching connection (24).

4. Control device according to one of claims 1 to 3,

characterized, in that at least one gap (48) between the at least one

heat generating component (15) and the cooling element (25) with the

Plastic compound (42) is filled.

Control device according to one of claims 1 to 4,

characterized,

that the plastic mass (42) of several, preferably good

thermally conductive layers (43, 44).

Control device according to claim 5,

characterized,

the material of the layers (43, 44) differs in their physical and / or chemical properties and / or their layer thicknesses.

Control device according to one of claims 1 to 6,

characterized,

in that the circuit carrier (11) is in the form of a printed circuit board (14), and in that electrical connection elements of the plug connection element (12) are connected by press-fitting technology and / or bonded connections to electrically conductive regions of the printed circuit board (14).

Control device according to one of claims 1 to 6,

characterized,

in that the circuit carrier (11) is in the form of a flexible conductor foil (45) or a flexible printed circuit board (14), and in that electrically conductive surface regions (47) of the conductor foil (45) are connected to the

Plug connection element (12) are electrically connected.

Method for producing a control device (10), which is designed according to one of Claims 1 to 8,

characterized,

the plastic compound (42) is applied to the circuit carrier (11) in the dipping process.

10. The method according to claim 9,

characterized,

in that the plastic compound (42) is applied to the circuit carrier (11) by forming a plurality of layers (43, 44) in the dipping process with the interposition of at least one physical intermediate treatment.