US20090083980A1

US20090083980A1 - Cooling Body for Electronics Housing

Info

Publication number: US20090083980A1
Application number: US12/066,273
Authority: US
Inventors: Viktor Pfeuffer; Karl Smirra; Robin Zich
Original assignee: VDO Automotive AG
Current assignee: VDO Automotive AG
Priority date: 2005-09-09
Filing date: 2006-07-26
Publication date: 2009-04-02
Also published as: DE102005043055B3; EP1922177A1; JP2009508328A; WO2007028672A1

Abstract

A method for producing a cooling body including cooling ribs for an electronic housing, in particular for the automotive industry, includes producing extruded profile slabs having cooling ribs which extend in a parallel manner. The profile slabs are disposed next to each other in relation to a surface which includes cooling ribs that are disposed in parallel. The profile slabs are cut to length by a profile circular saw having step profiles. In this way, the production process for producing a cooling body from extruded aluminum is variable for the first time in relation to the shape of the cooling body in such a way that the individual requirements in the electronic housing in relation to heat which is to be withdrawn, sealing between the housing and cooling body, and size of the cooling body, are taken into account. It is particularly suitable for use in the automotive industry.

Description

The invention relates to a method for producing a cooling body with cooling fins for an electronics housing, particularly for the automotive industry.
Housing concepts which impose high requirements on the three-dimensional flexibility of shape of the housing or which have to be adapted to very specific three-dimensional spaces are implemented as a rule using an injection molded die-cast aluminum or plastic housing. If a good transfer of heat out of the housing is to be enabled, a sealed housing system should be developed made entirely of aluminum die-cast parts or embodied in plastic in only some areas.
To create a seal between the edge of the cooling body and the plastic housing which it surrounds a sealable component configuration with encapsulating means of with a dispensed or sprayed-on seal must be produced for both parts to be sealed. A parts geometry suitable for this has flange-like circumferential surfaces which are then easy to provide with a suitable sealing configuration. Such a configuration suitable for sealing is relatively easy to implement for the plastic housing and for the cooling body in a respective die-casting concept.
To embody a cooling body so that the greatest possible diversity of designs is possible as regards the housing for accepting a circuit, a cooling body with a housing for an electronic circuit emitting heat is known from DE 100 14 459 A1, in which at least the side walls of the housing consist of plastic and are permanently connected by overmolding the upper section of the cooling body to said section. This layout achieves a separation of the functions. The cooling body itself basically consists of any given heat-conducting material; it is expediently a die-cast aluminum part or an extruded aluminum part.
Disclosed in DE 198 15 110 A1 is a heat dissipation arrangement with a cooling body for removal of heat from a housing containing electrical components with an electrically-conductive surface, which has a mechanical connection between the cooling body and the housing which is provided by a layer of adhesive. An electrically-conductive connection between the cooling body and the housing is made by a connecting element, which is connected to the electrically-conductive surface area of the cooling body and the housing.
DE 102 47 828 A1 describes a heat-dissipating and heat-emitting housing made of plastic with overmolded cooling body. The housing features two plastic housing shells and a cooling body arranged in the housing, which is permanently connected to one of the two plastic housing shells by overmolding of a part of the cooling body and which features a non-overmolded section as a component mounting surface, with the housing acting as a cooling body for the components mounted there. In this case the cooling body is embodied as a die-cast or extruded aluminum part.
The disadvantage of the prior art is that the heat transfer coefficient is not optimum for cooling bodies made of die-cast aluminum and that a flexible shape of the cooling body tailored to the respective requirements is not possible with an extruded version. The alternate use of extruded aluminum profiles and the cost benefits arising from this realization compared to die-cast aluminum designs for specific three-dimensional shapes could not previously be realized, since processes did not allow structures across the direction of extrusion to be produced at low cost.
Using this as its starting point, the underlying object of the present invention is to create an easy-to-produce cooling body, which has a better heat transfer coefficient by comparison with the prior art, can be flexibly arranged as regards its three-dimensional shape and makes possible a easy-to-handle seal between housing and cooling body, and does all this cost-effectively.
This object is achieved by a method for producing a cooling body with the method steps as claimed in claim 1. Advantageous embodiments and developments of the method, which can be used individually or in combination with one another, are the object of the dependent claims.
The method in accordance with the invention for producing a cooling body with cooling fins for an electronics housing, particularly for the automotive industry, comprises the following steps: Production of extruded profile slabs with cooling fins running in parallel to each other; Arranging the profile slabs alongside one another in relation to a surface with cooling fins arranged in parallel; cutting the profile slabs to length using a profile circular saw with a step profile. Cooling bodies made from extruded aluminum have an appr. 30% better heat transfer coefficient than cooling bodies made from die-cast aluminum. In addition the inventive production method provides the option of varying the embodiment and the number of cooling fins so that they can be tailored to the respective requirements, i.e. the cooling fins can be longer, thinner and closer together or be shaped with microprofiling. Cutting the profile slabs to length with a profile circular saw forms step profiles across the direction of extrusion, which have a flat flange structure which serves as a sealing interface to the cooling body. The advantage of the profile circular saw lies in its ability to produce a large number of cooling bodies cost-effectively in one simple step, which normally could only be created by a machining process with extruded components with flange planes across the direction of extrusion. As a rule this is an individual process which is excluded for high volumes for cost reasons. The “cutting to length” step also performs the step “produce transverse profile on extruded part” in the inventive method. This means that the process sequence is shorter.
Preferably profile slabs are used with flange-type profiling arranged in parallel the cooling fins. Overall this produces a cooling body which features a circumferential profiling on all four sides, which makes a simple seal between housing and cooling body possible.
It is preferable to extrude profile slabs with a different number of cooling fins, so that different requirement profiles for cooling intensity can be fulfilled. The embodiment of the cooling body or of the cooling fins can thus be varied and tailored individually to the conditions obtaining in the electronics housing.
The inventive method makes it possible to produce cooling bodies with different geometry in respect of length, width and profile depth, so that an adaptation to the conditions demanded in the housing is possible.
Preferably the profile slabs are bent to form different lengths of cooling body, so that it is possible, to provide individually shaped housings with suitable cooling bodies.
Preferably the profile slabs are extruded from a heat-conduction material such as aluminum for example, which has an particularly good heat transfer coefficient in extruded form.
It is preferable to undertake the process of cutting the slabs to length with a profile circular saw which allows a variable configuration of the circular saw blades, so that flange-type profiles running across the direction of extrusion which serves as the sealing interface between housing and cooling body can be tailored individually to the conditions in the housing. The individual configuration of the circular saw blades of the profile circular saw means that no individually manufactured tools have to be provided. In addition no delays arise in the production process, since the circular saw blades can be exchanged without problems.
A further advantage of the invention is that the cutting-off and profile step can be undertaken in one operation, so that process execution is also simplified and is more cost-effective overall.
The present invention advantageously creates for the first time a production process for a cooling body made of extruded aluminum, which is variable in relation to the shape of the cooling body such that the individual requirements in the electronics housing in respect of heat to be withdrawn, seal between housing and cooling body and size of the cooling body can be taken into account. It is particularly suitable for applications in the automotive industry.
Further advantages and embodiments of the invention will be explained below with reference to exemplary embodiments as well as with reference to the drawing.

The figures show the following schematic diagrams:

FIG. 1 an exploded view of an electronics housing in which the cooling body mounting conditions are illustrated with reference to a typical housing;

FIG. 2 a perspective view of an inventive cooling body in the mounted state;

FIG. 3 a sectional view of the inventive cooling body in a mounted state;

FIG. 4 a sectional view of the electronics housing with inventive cooling body;

FIG. 5 a sectional view of a circular saw in the process of sawing through a profile slab;

FIG. 6 a perspective view of the profile slabs according to FIG. 5 after the sawing process;

FIG. 7 a perspective view of a process of sawing profile slabs arranged next to each other with a circular saw;

FIG. 8 a sectional view of a profile circular saw in the process of sawing through a profile slab;

FIG. 9 a perspective view of the profile slabs according to FIG. 8 after the sawing process;

FIG. 10 a perspective view of a process of sawing profile slabs arranged next to each other with a profile circular saw;

FIG. 11 a perspective view of the profile circular saw and

FIG. 12 a perspective view of a process of sawing through a hollow slab profile.

FIG. 1 shows an exploded view of an electronics housing with a cooling body 2. The electronics housing 1 is preferably formed in two parts and has an upper housing part 3 and a lower housing part 4. A preferably rectangular recess 5 is arranged in the upper housing part 3 in which the cooling body 2 is supported. The cooling body 2 has cooling fins 6 arranged in parallel to each other and sealing interfaces on all four circumferential sides. Electrical carrier components, such as printed circuit boards 7 for example are arranged in the electronics housing 1.
FIG. 2 shows a perspective view of the inventive cooling body 2 in the mounted state. The cooling body 2 lies in the recess 5 of the upper housing part 3, with the cooling fins 6 of the cooling body 2 protruding out of the upper part of the housing 3.
FIG. 3 shows a sectional diagram of the cooling body 2 in the mounted state. The cooling 2 is designed in this exemplary embodiment so that it preferably has circumferential profiles 8 at the sides running in parallel and across the cooling fins 6. The circumferential profiles 8 are embodied so that they protrude sideways over the area 9 in which the cooling fins 6 are arranged. This produces an easily-accessible sealing option with a sealing mass 10 e.g. based on encapsulation or with a dispensed seal between the cooling body 2 and the upper section of the housing 3 at the sides of the circumferential profile 8 running parallel to and across the cooling rubs 6.
FIG. 4 shows a further option for enabling a secure seal between the upper part of the housing 3 and the cooling body 2. In such a case the sealing mass 10 is applied to contact surfaces 11 which are produced by the circumferential profile 8. An insert seal or a molded-on seal can also be placed here between contact surface 11 and a surrounding shoulder 3 a of the upper section of the housing 3. These contact surfaces 11 run in parallel and across the cooling fins 6 of the cooling body 2 and are pressed down on by the upper section of the housing 3. The sealing effect is promoted by the fact that there is a compression force between the upper section of the housing 3 and the lower section of the housing 4 when the sections are pressed together, which promotes the distribution of the sealing mass 10 and thereby the sealing effect.
FIG. 5 shows a cross section of a circular saw 12 during the process of cutting through a profile slab 13.
FIG. 6 shows a perspective view of the profile slab 13 depicted in FIG. 5 after the sawing process. The cooling body 2 separated from the profile slab 13 by the sawing process has the circumferential profiling 8 running in parallel to the cooling fins 6.
FIG. 7 shows a perspective view of the sawing process of profile slabs 13 arranged next to each other with a circular saw 12.
FIG. 8 shows a sectional view of a profile circular saw 14 during the process of sawing through a profile slab 13. By using the profile circular saw 14 with a cutting blade arranged centrally 15 and two cutting blades 16 arranged to the sides of the cutting blade 15 cooling bodies 2 are produced during the sawing process which also have a circumferential profiling 17 running across the direction of extrusion.
FIG. 9 shows a perspective view of the profile slab 13 depicted in FIG. 8 after the sawing process. The cooling body 2 separated from the profile slab by the sawing process has circumferential profiling 8, 17 on all four circumferential surfaces.
FIG. 10 shows a perspective view of a sawing process of profile slabs 13 arranged next to one another with a profile circular saw 14.
FIG. 11 shows a perspective view of the profile circular saw 14. The profile circular saw 14 has a large cutting blade 15 at the sides of which are arranged two smaller cutting blades 16. The cutting blades 15, 16 of the profile circular saw 14 can be assembled matched individually to the requirement profile, i.e. in respect of their diameter and their profile. A shaft element 18, on which the cutting blades 15, 16 are placed and attached is used for this purpose.
FIG. 12 shows a perspective view of a process of sawing through a hollow profile slab 19. The method in accordance with the invention is suitable both for full profiles and for hollow profiles.
The present invention advantageously creates for the first time a production process for a cooling body (2) made of extruded aluminum, which is variable in relation to the shape of the cooling body (2) such that the individual requirements in the electronics housing (1) in respect of heat to be dissipated, sealing between housing (1) and cooling body (2) and size of the cooling body (2) can be taken into account. It is particularly suitable for applications in the automotive industry.

Claims

1-8. (canceled)

9. A method for producing a cooling body with cooling fins for an electronics housing, the method comprising the following steps:

producing extruded profile slabs with cooling fins running parallel to each other;

aligning the profile slabs alongside each other relative to a surface with the cooling fins disposed in parallel; and

cutting the profile slabs to length with a profile circular saw having a step profile.

10. The method according to claim 9, which further comprises providing the profile slabs with flange-type profiling disposed parallel to the cooling fins.

11. The method according to claim 9, which further comprises extruding the profile slabs with a different number of cooling fins.

12. The method according to claim 9, which further comprises producing the cooling body with a different length, width and profile depth geometry.

13. The method according to claim 9, which further comprises bending the profile slabs to form cooling bodies of different sizes.

14. The method according to claim 9, which further comprises extruding the profile slabs from aluminum.

15. The method according to claim 9, which further comprises carrying out the step of cutting to length with the profile circular saw by using a profile circular saw permitting a variable configuration of circular saw blades.

16. The method according to claim 9, which further comprises performing the step of cutting the slabs to length and cutting a profile in one step.

17. The method according to claim 9, wherein the electronics housing is an automotive industry housing.