WO2014083254A1

WO2014083254A1 - Electronic assembly comprising a component having a plurality of heat dissipation surfaces

Info

Publication number: WO2014083254A1
Application number: PCT/FR2013/052688
Authority: WO
Inventors: Damien Morin; Nejoua BENHAMOUDA
Original assignee: Valeo Systemes De Controle Moteur
Priority date: 2012-11-28
Filing date: 2013-11-08
Publication date: 2014-06-05
Also published as: FR2998761A1; FR2998761B1

Abstract

The invention relates to an electronic assembly (1), especially for a module for controlling an electric motor, comprising: at least one electronic power component (2) comprising outer surfaces (21); and a housing (12) for receiving the electronic power component; characterised in that said housing (12) defines a receiving element having at least one side wall (131, 132), and in that said component (2) is designed so as to be held in said receiving element by pressing at least part of the surfaces (21) thereof on the side wall (131, 132) of the receiving element.

Description

ELECTRONIC ASSEMBLY COMPRISING A COMPONENT WITH FACES OF

MULTIPLE THERMAL DISSIPATION

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to an electronic assembly, in particular for an electronic control module of an electric motor, in particular an electric motor of a vehicle used for electric or hybrid motor vehicles. More particularly, the invention is directed to power electronics having multiple heat dissipation faces.

It will be understood by component with multiple heat dissipation faces, in the context of the present application, any electronic component whose heat dissipation is non-planar, in contrast to so-called planar power components. In these components, the heat dissipation is effected by several faces that extend in different planes.

Curved surface, in the context of the present application, any non-planar surface having a plane of tangency at any point.

By internal side of the side wall of the housing, the face of said wall facing towards the inside of the housing, i.e. the space where the power component will be positioned.

An angle of inclination substantially equal to another angle of inclination will be understood, in the context of the present application, any inclination angle whose value in degrees is equal to the value of the other angle of inclination. inclination to plus or minus ten percent.

[0006] By central axis of the housing, in the context of the present application, it will be understood that any axis perpendicular to the bottom of a housing such that the side walls of the housing are symmetrical to one another with respect to said axis.

STATE OF THE PRIOR ART

The power components see their efficiency and their service life decrease because of their heating in operation. The more a power component is required to withstand high power, the more it heats up. It is necessary to ensure a cooling of these components, in order to obtain a good performance of the component and to improve its service life. As illustrated in Figure 1, it is known to deposit a power component 72 on a water box that serves as a cooling means, and hold together by clamping and resealing. For power components with multiple heat dissipation faces, since the heat dissipation is not planar, the cooling of such a component deposited on a water box is not effective. In the example shown in FIG. 1, the power component 72 is of the coil type 721 and comprises a ferromagnetic core 75 and a winding 74. The coil 72 is deposited on a casing 71 made of a thermally conductive material, of the aluminum type, itself disposed above a cooling means (not shown). The winding 74 is not fully in contact with the housing 71. Only a portion (not visible in the figure) of the windings 74 may be in contact with the bottom 71 1 of the housing 71 and can be effectively cooled. The portion of the coil 74 located above the coil is not effectively cooled because it is not in contact with any heat transfer means. The heat exchange between all the active parts of the coil and the cooling means is not sufficiently effective. In a coil, the active parts include the coil which is the seat of an electric current.

Typically, the coil 721 is wound on a support 76. The retention of the coil 721 against the housing 71 is achieved by screws inserted in holes 760 arranged in the support 76 and corresponding threaded holes in the housing 71. However, vibrations experienced by the assembly can cause stresses between the housing 71 and the support 76. Deformations or breaks in the support 76 may occur, which can cause a failure of the coil 721. The coil 72 can be held by resin 77. But the resin casting process is constraining because it requires polymerization furnaces. In addition, once the component held by the resin, it is permanently secured to the housing 71 and unmountable.

US20090201648 discloses an assembly in which a non-planar heat dissipation face component is introduced into a cooling medium. The component bears on a horizontal surface of the support. SUMMARY OF THE INVENTION

The invention aims to remedy all or part of the disadvantages of the state of the art identified above, and in particular to propose means for positioning a component with multiple heat dissipation faces so as to improve the recooling.

In this purpose, one aspect of the invention relates to an electronic assembly, in particular for a control module of an electric motor, comprising:

at least one electronic component of puissance having external faces;

a housing for receiving the electronic power component;

characterized in that said housing defines a housing having at least one side wall, and in that said component is configured to be held in said housing by pressing at least a portion of its faces on the side wall of the housing .

In other words, when the electronic component is held in the housing, the component rests on the sidewall ite. Thanks to the side walls, the component can be held in the housing without using resin. When the component is inserted into the housing, faces of the component bear against the side wall of the housing, the power component is thus easily positioned in the housing defined by the housing. In the assembly according to the invention, the component placed in the housing, is not cooled only at its lower part but can be cooled also on its faces in contact with the side wall, for example by means of contact areas of the faces with the side wall of the housing.

Thus, the housing being in a thermally conductive material, alumin ium for example, a component placed in the led it housing of said housing can be naturally, and effectively cooled by heat transfer if the housing is brought into contact with a means of cooling.

In addition to the main features which have just been mentioned in the preceding paragraph, the electronic unit of pu issance according to the invention may have one or more additional characteristics among the following, considered individually or according to the technically possible combinations.

According to one embodiment, the inner face of said side wall of the housing is configured to correspond with the shape of the faces of the component. When the component is in the housing, the component faces conform to the inner face of the sidewall. The heat exchange surface is optimized thanks to this match between the shapes.

According to one embodiment, the housing comprises an opening through which the component is adapted to be introduced into the housing. The side wall extends from said opening to a bottom of the housing so that the section of the housing with a transverse plane gradually decreases. Thus, the housing is substantially funnel-shaped. In particular, the plane is transversal to a direction of insertion of the component into the housing. The component, simply deposited on the side wall, can be maintained in the housing by gravity alone.

According to one embodiment, the housing has a shape in a direction of insertion of the component which is substantially frustoconical, conical, or rounded. In particular, the frustoconical or conical shape is prismatic or revolution. This direction is in particular a direction from the opening of the housing to the bottom of the housing.

According to a mode of real isation, a thermal interface is dposposed between the faces of the component and the side wall. These faces of the component being supported on the side walls of the housing, the thermal interface optimizes heat exchange between the housing and the component. The thermal interface makes it possible to fill the air cavities which can result from the manufacture of the elements, the air being a very bad thermal conductor. The thermal interface also makes it possible to avoid short circuits at the crankcase / component interface, the component often being under high voltage, in the case of use in a motor vehicle.

According to one embodiment, the assembly comprises a wedge between the faces and the side wall, said wedge being adapted to limit the compression of the thermal interface between the faces of the component and the side wall of the housing. The wedge can be a part of the component or a groove on the internal faces of the side walls of the housing or an additional part separate from the housing and the component;

According to a real isation mode, the assembly comprises a plating member bearing on one side of the component so as to exert a plating force on said component. Once the component positioned in the housing, the plating member advantageously secures the positioning of the component in the housing partially exerting a plating force on said component. This plating member may be a clamping member, for example of the tongue type, disposed above the component (opposite a bottom of the housing). The plating member ensures the position of the component in case of reversal of the assembly to which the component belongs.

According to one embodiment, a first face of the component is configured to bear on a first side wall of the housing and a second face of the component is configured to bear on a second side wall of the housing so as to maintain the component in said housing. The first and second faces of the component being supported on the first and second side walls of the housing, the power component is easily positioned in the defined housing.

According to one embodiment, the side walls respectively have a first internal face and a second internal face converging towards each other so that the electronic component is held in the housing by bearing on the faces. internal. In particular, the first and second side walls of the housing extend from an opening for introducing the component into the housing towards the bottom of the housing, forming a slope and approaching a central axis of the housing. The central axis of the housing corresponds in particular to a bearing direction of the component in the housing. For example, the housing has substantially a rail shape extending in a first direction. The housing has a substantially V-shaped or U-shaped section in a second direction perpendicular to the first direction.

According to one embodiment, the inner faces of the side walls are flat or curved. In particular, the flat internal faces have an angle of inclination with respect to a central axis of the housing. For example, the angle tilt is greater than 0.5 °. This minimum value of the angle of inclination makes it easier to mount the component in the housing.

According to one embodiment, the electronic power component is a coil having a winding, the support faces of the component comprising at least a portion of the outer face of said winding. The outer face of the winding is the surface formed by the winding at the periphery of the coil. In a coil, the winding is the seat of an electric current which is a source of heating of the coil. By bearing on a side wall of the housing, the outer face of the winding allows a retention of the coil in the housing, while transmitting its heat to the housing, and cooling of the coil is improved.

According to a mode of real isation, the winding is formed around a coil support; the shape of said coil support being adapted so that the outer face of said winding matches the shape of the side wall of the housing. In other words, the shape of said coil support is adapted so that the outer face of the coil matches the shape of the side wall of the housing. The support may in particular be a plastic part positioned between the core of the coil and the winding. The support may be shaped so as to give a flat or curved shape to the outer face of the winding which corresponds to a flat or curved shape of the side wall. In this way, the winding support gives shape to the windings of the coil in adequacy with the side walls of the housing, which improves a heat removal of the coil by the housing. In particular, in a variant comprising the wedge, it may be secured to the support. The shim can then correspond to a portion of the support defining the width of the winding.

According to a mode of real isation, the assembly comprises a plurality of electronic power components juxtaposed in the housing along the side wall of the housing.

According to one embodiment, said casing is made of a thermally conductive material. This improves the cooling of the component by the housing.

According to one embodiment, once the component introduced into the housing, an interval separates the component from the bottom of the housing. This interval allows to improve the maintenance of the component in the housing by allowing to exert a vertical force (that is to say in a direction of support of the component) on the component towards the bottom of the housing to drive the component into the housing.

According to a particular embodiment, the first and second side walls are respectively shaped wall rising from the bottom of the housing. Thus, the housing has a small footprint. Preferably, these walls are profiled so that the width of the wall increases gradually from the end of the wall which is opposite the bottom to the end of the wall near the bottom. This profiling walls provides a more effective seating for the electronic component when inserted into the housing, the component then being held in the housing at least partially, if not completely, thanks to its support on the side walls.

The invention also relates to a system comprising an electronic assembly according to the invention and a cooling means in contact with the housing of the assembly. The cooling means may comprise, for example, channels for the circulation of a cooling fluid, and / or cooling fins, etc. The cooling means may be in contact with, for example, a bottom wall of the housing and / or with an outer face of the side wall of the housing. By being in contact with the cooling means, the casing, itself in contact with the faces of the component, allows efficient cooling of the power component.

In particular, the bottom of the casing preferably has a first face facing the electronic component and a second face opposite to the first face, said second face being intended to come into contact with a cooling fluid. More particularly, the bottom of the housing can be shaped to define channels when the second face of the bottom comes into contact with a corresponding surface. These channels define passageways for the cooling fluid.

BRIEF DESCRIPTION OF THE FIGURES Other features and advantages of the invention will emerge on reading the description which follows, with reference to the appended figures, which illustrate:

Figure 1 is a schematic view of an electronic assembly of the prior art;

FIG. 2 is a diagrammatic view of a casing of an electronic assembly according to one embodiment of the invention;

Figure 3 is a schematic view of an electronic assembly according to one embodiment of the invention;

Figure 4 is a schematic sectional view of an electronic assembly according to one embodiment of the invention;

Figure 5 is a schematic sectional view of an electronic assembly according to one embodiment of the invention;

Figure 6, an enlargement of the assembly illustrated in Figure 5;

Figure 7 is a schematic sectional view of an electronic assembly according to one embodiment of the invention;

FIG. 8, a schematic view of a system comprising a plurality of power components according to one embodiment of the invention;

Figure 9 is a perspective view of a coil used in an assembly according to the invention;

FIG. 10, a front view of the coil of FIG. 9.

For clarity, identical or similar elements are identified, unless otherwise specified, by identical reference signs throughout the figures. DETAILED DESCRIPTION OF AN EMBODIMENT

In Figure 2 is illustrated a housing 12 of an electronic assembly according to the invention. The housing 1 2 defines a housing 13 having a bottom 133 of which rise a first side wall 131 and a second side wall 132. The first side wall 131 and the second side wall 132 are not necessarily identical. The housing 13 further comprises an opening 134 (delimited in the figure by dotted lines) allowing the introduction of a power component into the housing 13, for example as illustrated in FIG. casing 12 is for example made of a thermally conductive material, preferably homogeneous in order to optimize heat transfer within said casing 12. It may for example be made of aluminum. The casing 12 is disposed on a cooling means 1 January. The casing 12 is for example in contact with the cooling means 1 1 by the bottom 133, heat from the first 131 and second 132 side walls being communicated to the cooling means 1 1 by thermal conduction. The cooling means 1 1 may comprise channels 1 10 containing cooling fluid in contact with the casing 12. In the example shown, the channels 1 10 are formed by walls coming from the casing 12. However, the channels could be formed by a different element of the housing 12.

The introduction of the component can be done in the embodiment illustrated in Figure 1 by the top of the housing or the front or rear.

The housing 12 is configured to receive an electronic component 2 as shown in Figure 3. The volume power component 2, here shown, is a coil 24 having a ferromagnetic core 241 around which is wound a winding 242. The winding 242 represents the electrically active portion of the component 2. The winding 242 is connected to an electrically conductive element 5 in order to be electrically connected to an electrical circuit (circuit not shown in the figure).

Figure 4 shows a half of the electronic assembly 1 when the power component 2 is positioned in the housing 12. The first side wall 131 of the housing 13 defined by the housing 12 is visible in this figure. The internal faces 1310, 1320 of the side walls 131, 132 extend from the opening 1 34 towards the bottom 133 of the housing, forming a slope and approaching a central axis Xc of the housing 13. The internal faces 1310, 1320 of the side walls 131, 132 are flat and inclined at an angle of inclination with respect to the central axis Xc of the housing. The angle of inclination a is preferably greater than zero point five degrees to facilitate the molding / demolding of the housing. Thus, the housing 13 forms a funnel in which can be positioned the power component 2. A first face 21 and a second face 22 (visible in FIG. 5) of the power component 2 respectively bear on the first 131 and the second 132 side walls. of the housing 13. The faces 21, 22 of the component 2 correspond with the shapes of the side walls 131, 132. In particular, the faces 21, 22 are flat and inclined at the same angle as the angle with which the internal faces 1310 are inclined. 1320 of the side walls 131, 132. Thus, the power component 2 is positioned by adjustment when inserted into the housing 13 defined by the housing 12. The thermal contact surface between the component 2 and the housing 12 comprises both lateral faces 21, 22. This improves the heat dissipation with respect to a set of the prior art in which the dissipation is effected by a single face of the component. The housing 12 itself being in contact with a cooling means January 1, the component 2 can be effectively cooled.

An additional thermal interface 31, 32 is positioned between the faces 21, 22 of the component 2 and the internal faces 131 0, 1320 of the side walls 131, 132. This will be better understood with reference to FIG. a sectional view of an electronic assembly 1 and a cooling means 1 1. A first thermal interface 31 is disposed between the first face 21 of the component and the first side wall 132 of the housing 13; and a second thermal interface 32 is disposed between the second face 22 of the component and the second side wall 131 of the housing 13. In this embodiment, the first 31 and second thermal interfaces are the same. It could be a different thermal interface for each of the first 21 and second face 22 of the component 2, both in terms of their composition and their shape. The thermal interface 31, 32 may be, among others, gap gap type, electrical insulating film, thermal conductive mat, thermal grease or thermal conductive glue. The thermal interface can then be deposited on the component 2 or on the housing 12 before assembly. The thermal interface may also be a thermal resin cast in assembly 1 after assembly, in a process with or without evacuation and comprising a polymerization with or without an oven. The thermal interface 31, 32 may be phase-shifted. In this case, it can be deposited on the component 2 or on the housing 12 before assembly. Then, once assembly 1 assembled, it is put in an oven so that the interface adapts to the respective shape of the two parts.

The thermal interface 31, 32 makes it possible to fill the air cavities which penalize the heat exchange between the faces 21, 22 of the component and the walls. These cavities may result inter alia from the manufacture of the housing 1 2 (whose faces are not perfectly smooth) and the coil 24, the outer surface of the winding 242 is not perfectly smooth.

In order to imitate the com pression of the first 31 and second 32 thermal interfaces between the faces 21, 22 of the component 2 and the side walls 1 31, 1 32 of the housing 13, a first wedge 81 may be advantageously arranged to provide a space between the first face 21 of the power component 2 and the first 1 31 side wall of the housing 1 3; and a second shim 82 may advantageously be arranged to provide a space between the second face 22 of the power component 2 and the second 132 side wall of the housing 13. The first shim 81 is better visible in Figure 6 which has an enlargement 5. The shims 81, 82 provide a space between the faces 21, 22 and the inner faces 31 0, 1320 in which the thermal interfaces 31, 32 can be intercalated. avoids that a thermal interface 31, 32 is too compressed and can not escape due to the compression resulting from the pressing of the faces 21, 22 on the side walls 1 31, 1 32. A shim can be for example a groove or protrusion of a side wall of the housing. The shim may also be an additional piece, separate from the casing 12 and the component 2, which is interposed between the casing 12 and the component 2. Alternatively, the shim can be an element 81, 82 of the power component 2, for example as 6. In particular, the shim 81, 82 protrudes in length from the face 21, 22 of the component 2. In fact, in the component 2, it is shown in FIG. 5, which is a coil 24 comprising a winding 242, it is observed that the shim 81 exceeds the outer surface of the winding 242.

In the case where the power component is a coil 24, a part 6 can be inserted between the ferromagnetic core 23 and the winding 242 during the manufacture of the coil 24. This part 6, which is a support 243 Coil ("coil-former" in English), is preferably selected plastic material to facilitate the realization and for its good electrical insulation properties. The shaped part 6, 243 makes it possible to obtain a lateral peripheral surface of the component 2 which corresponds with the shape of the internal faces 1310, 1320 of the side walls 131, 132. In the example illustrated in Figure 5, the part 6 provides ir ir faces 21, 22 at an angle with the central axis Xc of the housing. Thus, the first 21 and second 22 faces of the component 2 are inclined at an angle substantially equal to the angle of inclination of the first 131 and second 131 side walls of the housing 13 relative to the central axis of the housing Xc.

[0043] FIG. 7 illustrates an alternative embodiment of an electronic assembly of puissance 1. In this alternative embodiment, the internal faces 1310, 1320 of the side walls 131, 132 are curved, as are the faces 21, 22 of the component 2 which bear on these internal faces 1 310, 1320. The power component 2 , shown here, is a coil 24 whose first face 21 and the second face 22 are curved. In the example shown, it is the winding 242 in combination with the plastic part 6 which gives their curved shape to the first 21 and second 22 faces of the component 2. However, the curved shape could have been given only by a process of FIG. particular winding or only by a curved shape of the piece 6.

A plating member, for example of the retaining tongue type (not visible in the figures), can be disposed above the component on a third face 23 of the component, opposite the bottom 133 of the housing 13, in order to keep the component 2 in position in the housing 1 2. Between the bottom 133 of the housing and the power component 2, a gap 126 may be provided. This gap 126 makes it possible to drive the power component 2 into the casing 12 in order to ensure a secure hold of the component 2 in the casing 12 by the side walls 131, 132.

FIG. 8 illustrates a system comprising a cooling means 11 and an electronic assembly 1 comprising a plurality of volume components 2 of the coil type. These components 2 are juxtaposed in the housing 1 3. Each component 2 has at least a portion of its outer face which bears on a side wall 1 31, 1 32 of the housing 12. The power components 2 could also have been arranged next two by two. In this case, only one of their first or second face would have been in contact with a side wall of the housing defined by the housing. Figures 9 and 10 show a perspective view and a front view of another exemplary coil 25 usable in the assembly 1 according to the invention. The coil 24 shown in FIGS. 3 to 8 has a ferromagnetic core 241 having two branches 241 a, 241 b facing each other. The winding 242 is wrapped around these branches 241 a, 241 b. The coil 25 of FIGS. 9 and 10 has a ferromagnetic core 75 divided into a central branch 241c and two lateral branches 241a, 241b. The winding 242 is made on the central branch 241 c. The coil 25 of FIGS. 9 and 10 may be disposed in the housing 1 2 as previously described for the coil 24 of FIGS. 3 to 8. In these two examples 24, 25 of coils the ferromagnetic core 241 can be formed from a combination of several elements 26. The element 26 can comprise a first substantially flat portion and two portions extending substantially perpendicular to the first portion from two opposite ends of the first portion.

The invention is not limited to the embodiments described above with reference to the figures and variants could be envisaged without departing from the scope of the invention. In particular, the faces 21, 22 of the component 2 could be directly in contact with the inner faces 1310, 1320 of the housing 1 3 without a thermal interface 31, 32. In this case, the shims 81, 82 would not be provided to allow a contact between the faces 21, 22 of the component and the inner walls 1 310, 1 320. In addition, all the figures have been described with reference to a power component, with multiple heat dissipation faces, of the coil type, but it can be any type of power component such as capacitance (in this case, the winding is in a housing, the shape of the housing can be modified to make it curved or inclined by a angle a) or a transformer (coiled elements also, in this case, the winding support is modified in order to tilt or bend it) etc.

In a particular example, the side walls 131, 132 are in the form of a wall as illustrated in the figures.

Claims

An electronic assembly (1), in particular for a control module of an electric motor, comprising:

at least one electronic power component (2) having external faces (21; 22);

a housing (12) for receiving the electronic component (2) power;

characterized in that said housing (12) defines a housing (13) having at least one side wall (131, 132), and in that said component (2) is configured to be held in said housing (13) by a in support of at least a portion of its faces (21; 22) on the side wall (131, 132) of the housing.

An electronic assembly (1) according to claim 1, wherein the inner face (1310, 1320) of said housing side wall (132, 131) is configured to correspond with the shape of the component faces (21, 22) ( 2).

3. Electronic assembly (1) according to claim 1 or 2, wherein the housing (13) comprises an opening (134) through which the component (2) is adapted to be introduced into the housing (13), and in wherein the side wall (131, 132) extends from said opening (134) to a bottom (133) of the housing (13) so that the section of the housing (13) with a transverse plane gradually decreases.

An electronic assembly (1) according to any one of the preceding claims, wherein the housing (13) has a shape in a direction of insertion of the component which is substantially frustoconical, conical, or rounded.

5. Assembly (1) according to any one of the preceding claims, characterized in that a thermal interface (31, 32) is disposed between the faces (21, 22) of the component and the side wall (131, 132).

6. Electronic assembly (1) according to claim 5, characterized in that it comprises a shim (81, 82) between the faces (21, 22) and the side wall (131, 132), said shim (81, 82 ) being adapted to limit the compression of the thermal interface (31, 32) between the faces (21, 22) of the component and the side wall (131, 132) of the housing (13).

7. Electronic assembly (1) according to any one of the preceding claims, characterized in that it comprises a plating member (4) bearing on one face (23) of the component so as to exert a plating force on said component.

8. Electrical assembly (1) according to any one of the preceding claims, wherein a first face (21) of the component is configured to bear on a first side wall (132) of the housing (13). and a second face (22) of the component is configured to bear on a second side wall (131) of the housing (13) so as to hold the component (2) in said housing (13).

9. Electronic assembly (1) according to claim 8, wherein the side walls (131; 132) respectively have a first internal face.

(1310) and a second inner face (1320) which converge towards each other so that the electronic component (2) is held in the housing (13) bearing on the inner faces (1310; 1320) .

10. Assembly (1) according to claim 9, wherein the inner faces (1310; 1320) are flat or curved.

1 1. Assembly (1) according to any one of the preceding claims, wherein the electronic power component (2) is a coil (24) comprising a winding (242), the bearing faces (21, 22) of the component (2 ) comprising at least a portion of the outer face of said winding (242).

12. The assembly (1) according to claim 11, wherein the winding (242) is formed around a coil carrier (243); the shape of said coil support (243) being adapted so that the outer face of said winding (242) corresponds to the shape of the side wall (131, 132) of the housing (13).

13. Assembly (1) according to any one of the preceding claims, comprising a plurality of electronic components (2) power juxtaposed in the housing (12) along the side wall (131, 132) of the housing (12).

14. Electronic assembly (1) according to any one of the preceding claims, wherein said housing (1 2) is a thermally conductive material.

15. System comprising:

an assembly (1) according to one of claims 1 to 14; and

a cooling means (1 1) in contact with the housing (12).